Environmental Health

MPH Ist Year
Prabesh Ghimire
Environmental Health

Environmental Health MPH 1st
Year
Table of Contents
UNIT 1: ENVIRONMENT AND HEALTH .......................................................................................................... 4
Concept of Environment and Health ........................................................................................................ 4
Ecosystem Approach to Health (Eco-Health) Concept .............................................................................4
UNIT 2: WATER AND HEALTH........................................................................................................................ 6
Types and Status of Water Sources, Concept of Water Quality, Guidelines, Standard and Indicator
Parameters, National and Transboundary Levels.....................................................................................6
Water Quality Monitoring......................................................................................................................... 8
Water Quality Surveillance ..................................................................................................................... 10
Water Related Diseases .......................................................................................................................... 12
Arsenic contamination, impact and mitigation measures in the context of Nepal................................13
Types of water purification and disinfection system in Nepal................................................................16
Slow Sand and Rapid Sand Filtration ..................................................................................................17
Water Quality and Quantity Situation in Nepal......................................................................................22
Concept of Water Sanitation and Hygiene .............................................................................................25
Overall Scenario of Water Sanitation and Hygiene ................................................................................26
Water and Sanitation Policies and Act/ Treaties Undertaken in Nepal..................................................30
UNIT 3: WASTE MANAGEMENT..................................................................................................................31
Solid Waste Generation, composition and existing mechanism of its management.............................31
Generation of Solid Wastes ................................................................................................................31
Composition of Solid Wastes ..............................................................................................................31
Existing Mechanism of Solid Waste Management in Nepal ...............................................................32
Types of hazardous wastes ..................................................................................................................... 33
Concept of Health Care Waste and its management status...................................................................33
Classification of Health Care Wastes ..................................................................................................33
Health care waste management in Nepal...........................................................................................34
Management of Health Care Wastes (Based on HCW management guidelines, Nepal) ...................34
UNIT 4: FOOD.............................................................................................................................................. 36
Concept of Food Security........................................................................................................................ 36
Food Quality Situation of Nepal..............................................................................................................36
Food Borne Diseases............................................................................................................................... 37
Mycotoxins.............................................................................................................................................. 38
©Prabesh Ghimire Page | 2

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Legal provisions of food quality..............................................................................................................39
UNIT5: AIR POLLUTION AND ITS IMPACT....................................................................................................41
Status of Air Pollution in Indoor and Outdoor Levels .............................................................................41
Status of Indoor Air Pollution..............................................................................................................41
Status of Outdoor Air Pollution...........................................................................................................41
Major Sources of Air Pollution................................................................................................................43
Types of Pollutants.................................................................................................................................. 43
Assessment of Environmental Burden of Disease Due to Indoor/Outdoor Air Pollution.......................47
Assessment of Disease Burden Due to Ambient Air Pollution............................................................47
Assessment Methods of Disease Burden due to Indoor Air Pollution................................................48
Indicator Parameter, Guideline, Standard for Measuring Air Pollutants, Prevention and Control........50
UNIT 6: HOUSING AND SETTLEMENTS........................................................................................................53
Urban Settlements.................................................................................................................................. 53
Rural Settlements.................................................................................................................................... 54
UNIT 7: OTHER ENVIRONMENTAL ISSUES ..................................................................................................55
Pesticides and Health Hazard .................................................................................................................55
Climate Change and Human Health........................................................................................................58
Concept of Environmental Risk Assessment...........................................................................................66
Environmental Impact Assessment.........................................................................................................70
Environmental Auditing .......................................................................................................................... 74
UNIT 8: INFECTIOUS AND TROPICAL DISEASE CONTROL............................................................................75
List of Some Vector Borne Diseases........................................................................................................75
Status of Vector Borne Diseases Prevalent in Nepal ..............................................................................75
Vector Borne Diseases Control Measures in Nepal ................................................................................76
Integrated Vector Management (IVM) ...................................................................................................77
Integrated Pest Management.................................................................................................................77

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UNIT 1: ENVIRONMENT AND HEALTH
Concept of Environment and Health
Concept of Environment: According to J. M Last’s Dictionary of Epidemiology, environment is all that
which is external to the individual host. It can be divided into physical, biological, social and cultural
factors, any or all of which can influence health status in populations.
Components of environment
i. Physical: Noise, health, ionizing and non-ionizing radiation
ii. Chemical: Pollutants, toxic wastes, pesticides, volatile organic compounds
iii. Biological: Microorganisms present in food and water, insect and animals
iv. Socio-economic: Access to safe and sufficient health care, culture, etc.
Environmental health comprises those aspects of the health, including quality of life, that are determined
by physical, chemical, biological, social and psychological factors in the environment. It also refers to the
theory and practice of assessing, correcting, controlling and preventing those factors in the environment
that can potentially affect adversely the health of present and future generations. (WHO, 1993)
Facets/ Multi-disciplines of environmental health
i. Environmental epidemiology: Associations between exposure to environmental agents and
subsequent of disease.
ii. Environmental toxicology: Causal mechanisms between exposure and subsequent development of
disease.
iii. Environmental engineering: Factors that govern and reduce exposure.
iv. Preventive medicine: Factors that govern and reduce disease development.
v. Environmental Law: Development of appropriate legislation to protect public health
Ecosystem Approach to Health (Eco-Health) Concept
- Eco-health is an emerging field of study researching how changes in the earth’s ecosystems affect
human health.
- It examines changes in the biological, physical, social and economic environment relates these
changes to human health. Example: increase in ARI rates due to air pollution.
- Eco-health strives to provide innovative, practical solutions to reduce or reverse the negative health
effects of ecosystem change.
- Eco-health brings multiple specialist disciplines (epidemiologists, physicians, ecologists, economists,
social scientists, planners and others) together to study and understand how ecosystem changes
affect human health.
Key principles of Eco-health: (According to Dominique Charron)
i. System thinking
- The components parts of a system should be understood in the context of their relationships with
each other and with other systems, rather than in isolation.
ii. Transdisciplinarity:
- Transdisciplinarity implies an inclusive vision of ecosystem-related health problems from multiple
disciplines such as researchers, community representatives and decision makers

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iii. Participation
- Eco-health approach aims to achieve consensus and cooperation among community, scientific and
decision-making groups.
iv. Gender and social equity
- Eco-health recognizes that the respective roles of men and women and various social groups should
be analyzed.
v. Sustainability
- Eco-health research should aim to make ethical, positive, and lasting changes which are
environmentally sound and socially acceptable.
vi. Knowledge to action
- Knowledge generated by research should be used to improve health and well-being through an
improved environment.
Advantages of eco-health approach
- Helps understand and make changes to complex environmental health problems.
- Reframes health issues in the context of ecosystems, people and their livelihoods.
- Involves multi-disciplinary teams.
- Has impact because it involves local people and responds to their needs.
- Promotes social justice for women and other marginalized groups.
Concept of Environment Health and Sustainable Development
- It is very essential to understand the key linkages between environmental health and sustainable
development objectives. After the Rio +20 UN Conference on Sustainable Development, the agenda
of sustainable development has become a guiding principle for environmental policy and international
development.
- Sustainable development is often viewed as a development that meets the needs of the present
without compromising the ability of future generations to meet their own needs.
- Poor health which is often a consequence of environmental exposures traps populations in poverty,
and therefore must be addressed to achieve development goals.
- Avoiding unintended consequences of development on the environmental health is essential to
achieving sustainability objectives.
- The environmental health community can make three major contributions to achieving sustainable
development objectives:
o Supporting efforts to reduce modifiable environmental exposures that contribute to perpetuate
poverty.
o Characterizing the environmental impacts of existing industries, technologies and land use
patterns that are harmful to human health and
o Foreseeing potential unintended health effects of green technologies, industries and occupation
that will evolve out of efforts to promote sustainability.
Linkages between environmental health and sustainable development
i. Environmental health affects development
- Poor public health due to environment exposures constraints development works
- Estimated 25% of global burden of disease is attributable to modifiable environmental risk factors.

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ii. Development affects environmental health
- Environmental contamination and rise of disease burden attributable to environment.
- Exploitation of natural resources
- Adverse land-use
UNIT 2: WATER AND HEALTH
Types and Status of Water Sources, Concept of Water Quality, Guidelines, Standard and
Indicator Parameters, National and Transboundary Levels
Safe and Wholesome Water
Drinking water should be safe as well as wholesome. Water is termed safe when it does not harm the
consumer even when ingested over prolonged periods. Safe and wholesome water thus, must be
 Free of pathogenic organisms
 Free from harmful chemical substances
 Acceptable to taste and appearance
 Usable for domestic purposes
Pressures for the deterioration of water quality
The contamination of water bodies take place due to
- Domestic waste water
- Solid waste
- Industrial waste
- Change in land use patterns
- Increase in use of agro-chemicals
- Man-made natural disasters
Health Impacts due to exposure of biological and physical agents in water
SN Agents Impact on health
A Physical
1 Manganese Adverse neurological effects
2 Arsenic Arsenicosis disease, skin cancer
3 Cadmium Kidney damage, bone demineralization
4 Chromium Damage to the nasal mucosa and lower respiratory tract
5 Fluoride Low concentration leads to dental caries while higher concentration with
thyroid malfunction, arthritis, dementia etc.
6 Lead Toxic and neurological diseases
7 Copper GI ulcerations and bleeding, CNS manifestations, including dizziness,
headache, convulsions
8 Aluminium Alzheimer’s disease or senile dementia
9 Mercury Harm to the brain, heart, kidney, lungs and immune system
B Biological
1 E. coli Diarrhoea
2 Shigella spp. Dysentery
3 Vibrio cholera Cholera
4 Cryptosporidium parvum Diarrhoea, cryptosporidiosis
5 Legionella Pneumonia (via inhalation)

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Water Quality Standards and Guidelines
The National Drinking Water Quality Standards, 2062 of Nepal includes a total of 27 parameters which
consists of six physical, 19 chemical and 2 microbiological parameters.
The suggested parameters and their guideline values are summarized in the table below:
SN Parameters Units Concentration Limits
A Physical Parameter
1 Turbidity NTU (Nephelometric Turbidity units) 5 (10)
2 pH 6.5-8.5
3 Color TCU (Total Color Units) 5(15)
4 Taste and Odor Non-objectionable
5 TDS (Total dissolved solids) Mg/L 1000
6 Electrical conductivity (EC) µs/cm 1500
B Chemical Parameters
7 Iron Mg/L 0.3 (3)
8 Manganese Mg/L 0.2
9 Arsenic Mg/L 0.05
10 Cadmium Mg/L 0.003
11 Chromium Mg/L 0.05
12 Cyanide Mg/L 0.07
13 Fluoride Mg/L 0.5-1.5
14 Lead Mg/L 0.01
15 Ammonia Mg/L 1.5
16 Chloride Mg/L 250
17 Sulphate Mg/L 250
18 Nitrate Mg/L 50
19 Copper Mg/L 1
20 Total hardness Mg/L as CaCO3 500
21 Calcium Mg/L 200
22 Zinc Mg/L 3
23 Mercury Mg/L 0.001
24 Aluminium Mg/L 0.2
25 Residual Chlorine Mg/L 01-0.2
C Microbiological Parameters
26 E.Coli MPN/ 100 ml 0
27 Total Coliform MPN/100ml 0 in 95% samples

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Water Quality Monitoring
According to National Drinking Water Quality Standards and Directive, 2005, the responsibility of water
quality monitoring has been entrusted to water supplier themselves.
The parameter and frequency of monitoring are as follows:
- For urban water supply system, the parameters and frequency will be as per the table below:
SN Parameter Monitoring Frequency
A Physical Parameter
1 Turbidity Daily
2 pH Daily
3 Color Daily
4 Taste and Odor Daily
5 TDS (Total dissolved solids) Monthly
6 Electrical conductivity (EC) Quarterly
B Chemical Parameters
7 Residual chlorine Daily
8 Ammonia Monthly
9 Chloride Monthly
10 Nitrate Monthly
11 Total Hardness Monthly
12 Calcium Monthly
13 Other parameters from National guidelines Yearly
C Microbiological Parameter
14 E.coli Monthly
16 Total coliform Monthly
- For rural water supply system, the microbiological parameters listed in the above table will be
monitored at least thrice a year (pre-monsoon, during monsoon and post monsoon season).
Monitoring frequency for other parameter will be same as mentioned in the above table.
Major tasks of water supplier during monitoring
- Controlling regularly the quality to ascertain that the water supplied complies with the National
drinking water quality standards.
- Periodic monitoring of all the components (from source to consumers) of the water supply system
from the perspective of sanitation and risk to health.
- Provide supervision, inspection and maintenance as part of operation of the water supply systems.
- Development of necessary infrastructures such as water quality testing laboratory and manpower for
quality control.
Scope of monitoring
Following factors should be considered while monitoring
- Type of water supply sources such as surface water, springs, dug-wells, shallow wells, deep wells etc
and quality of water.
- Type and size of the water supply system (pipe system treatment facilities)
- Local environmental settings (physical infrastructures, geography, etc.)
- Sanitation and hygienic condition surrounding the water supply system.

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- Socio-economic environment at the local level
- Site specific conditions for complying with the standards
- User’s opinion and suggestions regarding water quality
- Health and hygiene information (information on water related diseases)
Frequency of sampling and analysis for unpiped supplies
The minimum frequency of sampling and analysis for unpiped supplies is given in the table below:
Source and mode of
supply
Minimum frequency of sampling and analysis Remarks
Bacteriological Physical/ Chemical
Open wells for
community supply
Sanitary protection
measures; bacterial
testing only if situation
demands
Once initially for
community wells
Pollution usually
expected to occur
Covered dug wells and
shallow tube wells with
hand pumps
Sanitary protection
measures; bacterial
testing only if situation
demands
Once initially, thereafter
as situation demands
Situation requiring
testing: change in
environmental
conditions, outbreaks of
waterborne diseases or
increase in incidence of
waterborne diseases
Deep tube wells with
hand pumps
Protected springs Once initially, thereafter
Periodically for residual
chlorine if water was
contaminated and has
been disinfected
Selection of sampling points
- The sample should be representative in terms of temporal and spatial variability of quality.
- The sampling points should be uniformly distributed throughout the distribution system taking into
account of the population and number of branches.
- The samples should be taken from the reservoir and storage tanks.
- With due attention to the contamination risk, samples should be taken from source, low pressured
zones of the distribution pipeline and pipe joints.
Frequency of sampling and analysis for piped water supply system
The minimum frequency of sampling and analysis in the distribution pipelines for piped water supply
system should be as follows:
- For <5000 population served, the number of sampling is 1
- For 5000 to 100,000 population served, 1 per 5000
- For >100,000 population served, 1 per 10,000 population, plus 10 additional samples

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Water Quality Surveillance
The surveillance of drinking water quality includes continuous and vigilant public health assessment and
overview of the safety and acceptability of drinking water supplies.
According to National Drinking Water Quality Standards and Directives, 2005, the water quality
surveillance in Nepal includes the following
i. Tasks to be performed prior to surveillance:
In order to make surveillance simple, following tasks should be performed prior to surveillance
- Make an inventory of existing water supply schemes with population coverage, scheme types. Sizes/
condition, location specifics, etc.
- Investigate means for effective participation of local people in surveillance activities.
- Organize training programs for those who participate in surveillance works at various levels.
- Develop data collection forms applicable for all types of water supply schemes.
- Plan preliminary and then routine surveys
- Data collection and analyses of field works
- Develop regular site visit plans to all schemes
Parameter for monitoring and surveillance
The important parameters for monitoring and surveillance of drinking water quality, especially in, small
community water supply schemes are as follows:
- E. coli as microbiological parameter
- Turbidity, residual chlorine and pH if chlorine is used
Sanitary survey has been considered as one of the activities under monitoring and surveillance. For the
purpose of evaluating regular supply of safe and adequate water, a sanitary survey should be done with
onsite inspection of source, facilities, equipment, operation and maintenance of water supply schemes.
Sanitary survey should be done by water suppliers.
Following places and situations should be selected for sanitary survey and inspection:
- Sources and reservoirs
- Treatment systems
- Low pressure zones in pipeline
- Pipeline special joints
- Distribution system
- Pumps, pump facilities and controls
- Monitoring reporting and data verification
- System management and operation
Situation of Water Quality Surveillance in Nepal
The National Drinking Water Quality Standards and Implementation Directive 2005 have made the
Ministry of Health and its line agencies responsible for surveillance of drinking water quality in Nepal.
Even though a decade has passed since NDWQS was effective, the responsible agencies have not been
successful in establishing sustainable water quality surveillance and monitoring system.
In 2014, National Water Quality Surveillance Guidelines was prepared by MOHP to effectively implement
water quality surveillance activities. This guideline has established EDCD as a focal point and has set the
roles of various agencies in water surveillance. However due to several limitations, the implementation of
water quality surveillance activities is very poor.

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Water Quality Surveillance Activities of EDCD in 2071/72
• Water Quality Monitoring and Surveillance in 14 earthquake affected districts.
• Water Quality surveillance in water safety plans (WSP) implemented projects
• Capacity building of community member and health workers in water safety plants implemented
districts(Tanahu, Kaski, Nawalparasi and Gulmi)
Weakness
• No regular programs and budgets are available for water quality surveillance activities at
implementation level.
• Lack of trained human resources and technical expertise within MOHP and its implementing agencies
for surveillance works.
• Water Quality Surveillance Committee is almost non-existent and non-functional.
Strengths
• District level program implementation guidelines of EDCD for FY 2072/73 has provisioned D(P)HOs
for surveillance of water sources and surveillance and inspection of water samples at sources in
coordination with Division for Water Supply and Sanitation. This is expected to accelerate the
activities of surveillance at district and sub district levels.
• Water quality monitoring and surveillance has recently started from 14 earthquake affected districts.
• Capacity building of health workers done in four districts.
Role of water quality surveillance in reducing water borne disease in Nepal
- Coliforms in drinking water may indicate problems with water treatment or problems in the distribution
system. Surveillance requires public water systems to monitor for indicators of fecal contamination
and when coliforms are found, takes corrective action thereby reducing risk to water-borne diseases.
- Early detection of violations of national water standards via surveillance helps initiate timely corrective
actions ranging from upgrading water treatment to the distribution system including source protection.
- Water supply systems in Nepal are uniquely different and involve variable sources. So there is
likelihood that the risk and nature of outbreak may also differ between supply systems. In such
scenarios, surveillance can play an important role to assess the risk of outbreaks and then apply
controls to prevent such outbreaks from occurring.
- Surveillance program intends to establish the behavior of regular inspection of water quality. Such
behavior can help prevent water-borne diseases resulting from contamination of sources.
Process of Water Quality Surveillance in Nepal (According to Water Surveillance Guidelines)
Current water quality surveillance activities are guided by Water Surveillance Guidelines of MOH.
Surveillance is being conducted in areas where water safety plans are being implemented. The process
of water surveillance in Nepal includes three major approaches:
i. Auditing
- This includes auditing of water quality monitoring reports, appraisal of residual chlorine in treated
water, appraisal of water safety measures as provisioned in the water safety plan.
ii. Direct Assessment
- In this method, field inspections of water supply projects are done through direct observation of
pollution, contamination and other environmental status of water sources.
- It also includes testing of water samples to measure different parameters as directed in the NDWQS,
2005.

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- Where water tests are not feasible, sanitary inspections are done to collect necessary information.
Sanitary inspections are also preferred in cases where results of water tests cannot be obtained
immediately.
- A surveillance program based on direct assessment includes
o Sanitary inspections by qualified personnel
o Water sampling by qualified personnel
o Water quality testing using suitable methods at laboratory or using approved field testing
equipment.
o Reporting findings and follow up to ensure that they have been acted on
iii. Indirect Assessment
- In this approach, regular monitoring of water borne diseases (diarrhoea, cholera, typhoid, dysentery,
viral hepatitis, etc.) is done and once outbreak of such disease are found to occur, immediate
inspection of water supply systems for that particular area is conducted.
- Sanitary inspection is done to identify the cause of contamination and feedback provided to water
supply agencies for quality improvements.
Water Related Diseases
Water related diseases can be classified into four main categories:
Categories Causes Disease examples Control measures
Water borne
diseases
Caused by the ingestion of water
contaminated by human or animal
faeces or urine containing
pathogenic, bacteria , viruses or
parasites.
Cholera, typhoid,
amoebic and bacillary
dysentery, viral
hepatitis, leptospirosis,
giardiasis
- Improve water quality
and sanitation
Water Washed
Diseases
Caused due to lack of water or
poor personal hygience
Scabies, skin sepsis &
ulcers, yaws, trachoma,
conjunctivitis, flea, lice
and tick borne diseases,
soil transmitted
helminthes
- Increase water
accessibility
- Improve hygiene
practices
Water based
diseases
Caused by parasites found in
intermediate organisms living in
water. Infecting agents spread by
contact or ingestion of water. An
essential part of life cycle of agent
takes place in aquatic animal eg.
Snails, cyclops etc.
Schistosomiasis,
dracunculiasis and
some other helminthes
- Control aquatic
animals like snails
- Reduce surface water
contamination
Water related
diseases
Transmitted by insect vectors
which breed in water
Yellow fever, dengue,
encephalitis, filariasis,
malaria, onchocerciasis,
trypanosomiasis,
sleeping sickness
- Destroy breeding
sites
- Use personal
protection from insect
vectors (e.g. bed
nets)

Year
Arsenic contamination, impact and mitigation measures in the context of Nepal
Arsenic is a poisonous element naturally present at high levels in the groundwater of many countries like
Bangladesh, India, China and some parts of Nepal.
- Arsenic is highly toxic in its organic form.
- Contaminated water used for drinking, food preparation and irrigation of food crops poses the
greatest threat to public health from arsenic poisoning.
- Long-term exposure to arsenic from drinking water and food can cause arsenicosis leading to cancer
and skin lesions. It has also been associated with developmental effects, cardiovascular disease,
neurotoxicity and diabetes.
- The maximum permissible limit recommended by WHO in groundwater is 10 μg/L; however, in India,
Bangladesh, the accepted level is <50 μg/L in the absence of an alternative source of potable water
in the affected area
Arsenicosis
Arsenicosis is defined by the World Health Organization (WHO) working group as a “chronic health
condition arising from prolonged ingestion (not less than 6 months) of arsenic above a safe dose, usually
manifested by characteristic skin lesions of melanosis and keratosis, with or without involvement of
internal organs” (WHO Regional Office for South-East Asia 2003).
Arsenicosis is also called Arsenicism, blackfoot disease or black skin fever.
Characteristic cutaneous lesions of arsenicosis includes melanosis and keratosis
i. Melanosis
- It is characterized by diffuse and generalized hyper pigmentation, raindrop pigmentation,
leukomelanosis, localized or patchy pigmentation generally on the body or pigmentation of mucous
membranes.
ii. Keratosis
- Mild keratosis- Slight thickening or minute papules (<2 mm) of palms and soles, often associated with
a grit like texture.
- Moderate- Multiple, raised keratosis (>2 to 5 mm) appearing mainly or exclusively in symmetric
distribution of palms and soles.
- Severe- Large discrete of confluent keratotic elevations (>5mm) on palms and soles with nodular,
wart like or horny appearance.
Probability of Arsenicosis
The World Health Organization contends that a level of 0.01 mg/L poses a risk of 6 in 10,000 chance of
lifetime skin cancer risk and contends that this level of risk is acceptable.
From a 1988 study in China, the UD protection agency quantified the lifetime exposure of arsenic in
drinking water at concentrations of 0.0017 mg/L, 0.00017 mg/L and 0.000017 mg/L are associated with a
lifetime cancer risk of 1 in 10,000, 1 in 100,000, 1 in 1,000,000 respectively.
Prevalence of Arsenicosis in Nepal
- In Nepal, there is a serious problem with arsenic contamination particularly in Terai region, worst
being in Nawalparasi and other districts (Rautahat, Kailali and Siraha).

Year
- The overall prevalence of arsenicosis symptomatic patients among the risk regions is found to be
15.3% with 84.21% melanosis in trunk and 15.79% keratosis in sole and palm.
- It is estimated that about 2.6% of the total population, exposed to arsenic contaminated water with a
concentration more than 50 ppb, have a prevalence of arsenicosis.
- In the regions, namely Nawalparasi, Bara, Parsa, Rautahat, Rupandehi and Kapilvastu, the
prevalence of arsenicosis is, on average 2.2%.
- Research estimated that approximately 12.5 disability adjusted life years (DALYs) per 1000
population in Nepal is due to excess arsenic in the drinking water.
Health Effects of Arsenic Exposure
Acute Effects
- The immediate effects of acute arsenic poisoning include vomiting, abdominal pain and diarrhea.
- These are followed by numbness and tingling of the extremities, muscle cramping and death, in
extreme cases.
Long-term effects
- Cutaneous symptoms: pigmentation changes, skin lesions and hard patched on the palms and soles
of the feet (hyperkeratosis). These may be a precursor to skin cancer.
- In addition to skin cancer, long-term exposure to arsenic may also cause cancer of the bladder and
lungs.
- The International Agency for Research on Cancer (IARC) has stated that arsenic in drinking water is
carcinogenic to humans
- Other adverse effect that may be associated with long-term exposure includes developmental effects,
neurotoxicity, diabetes, pulmonary disease and cardiovascular disease.
- Arsenic-induced myocardial infarction, in particular can be a significant cause of excess mortality.
- In China, arsenicosis has been linked to “blackfoot disease”, which is a severe disease of blood
vessel leading to gangrene.
- Arsenic is also associated with adverse pregnancy outcomes and infant mortality.
Detection of Arsenic at Field Levels in Nepal
The detection of Arsenic at field level can be done by using very simple testing field-kits. Although the test
resulting from field kits are not precise, field-testing is considered best option for Nepal, where there are
only a few laboratories with competent personnel and equipments.
- Most arsenic test kits rely on the reduction of inorganic arsenic to arsine gas (AsH3) using zinc metal
and hydrochloric acid.
- The gas is allowed to pass through the mercury bromide indicator paper and the intensity of colour
indicates the concentration of arsenic.
- Many field kits including two Nepali kits are available in Nepal listed as follows:
o AAN kit (Japan)
o E- Merck Kit (Germany)
o NIPSOM Kit (Bangladesh)
o ENPHO Kit (Nepal)
o Modified AAN Kit (Nepal)
Diagnosis of Arsenicosis at field level
The accurate diagnosis of Arsenicosis requires both clinical and laboratory assessments. In Nepal where
laboratory measures are not uniformly available, the presence of arsenicosis at field levels can be
confirmed clinically. The case definition of Arsenicosis however uses two major diagnostic criteria:

Year
i. The presence of pigmentary and keratotic skin lesions
ii. Evidence of exposure to elevated levels of arsenic established by history of intake of arsenic
contaminated water, or by arsenic concentration in hair or nails.
The first diagnostic criteria require the presence on any of the pigmentary or keratotic skin signs.
We use a diagnostic algorithm for case definition in order to implement the case definition and classify
patients under field conditions.
i. Suspected case:
- A case is classified as suspected if a subject shows characteristic skin lesions or pigmentary changes
or keratosis on first presentation.
- The suspected case should be reclassified as probable, confirmed or non-arsenic after further clinical
examination.
ii. Probable case
- A suspected case is classified as probable if it belongs to one of the two categories on further clinical
examination:
o Showing melanosis and bilateral keratosis involving palms and soles
o Showing unilateral melanosis or keratosis after excluding other skin lesions mimicking arsenicosis
iii. Clinically confirmed cases
- A probable case is clinically confirmed if the presence of other arsenicosis stimulating skin lesions
has been ruled out by differential in-depth skin examination by either a trained dermatologist or an
arsenic expert.
iv. Non-arsenic case
- Non-arsenic case is a suspected or probable case in which specialist finds that the patient’s skin
condition is due to a cause other than arsenic exposure.
Once the cases are clinically confirmed, they may be subjected to laboratory tests for laboratory
confirmation of arsenicosis. However, due to limited resources, the cases can only be clinically confirmed
at field levels.

Year
Mitigation measure in Nepal
i. Installing Arsenic Removal Systems
- Technologies for arsenic removal may include oxidation, coagulation-precipitation, adsorption, ion
exchange and membrane techniques.
- Environment and Public Health Organization (ENPHO) has been promoting arsenic mitigation
options, such as Kanchan Arsenic Filter (KAF) in various arsenic affected districts.
- Filtration techniques such as three Gagri filters, arsenic biosand filters, using salts of aluminium and
iron are also in practice.
- A chemical packet containing ferric chloride (coagulant), sodium hypochlorite (oxidant) and charcoal
(adsorbent) are also mixed with water and filtered using ceramic filter.
ii. Substitution
- Substituting high-arsenic sources such as ground water with low arsenic sources such as rain water
and treated surface water.
- Low arsenic water can be used for drinking, cooking and irrigation, whereas high-arsenic water can
be used for other purposes such as bathing, washing clothes, etc
- Deep tube well, dug/ring well, pipe water supply can be safe and preferred options.
iii. Behaviour Change Communication
- Developing and implementing information and communication strategies to develop public awareness
on dangers of arsenic poisoning and use of practical mitigation technologies.
iv. Arsenic Testing
- Testing tube wells and hand pumps for arsenic and painting them with different colors can be
effective to reduce exposure to arsenic contaminated water if accompanied by effective awareness.
Types of water purification and disinfection system in Nepal
Water purification can be done in two scales:
i. Purification on a large scale
a. Storage of Water
- Physical: 90% suspended particles get settled down in 24 hrs.
- Chemical: Oxidation by aerobic bacteria; free ammonia reduced
- Biological: Decrease in bacterial counts by 90% in 5-7 days
b. Filtration of water
- Slow sand filtration
- Rapid sand filtration
c. Disinfection in large scale
- Chlorination
- Ozonation
- Ultraviolet radiation
ii. Purification on a small scale
a. Household purification
- Boiling

Year
- Chemical disinfection: Bleaching powder, chlorine solution, high test hypochlorite (HTH), Chlorine
(Halozone) tablets, iodone, potassium permanganate
- Solar disinfection (SODIS)
- Filtration: Ceramic filters, aquaguard and reverse osmosis treatment
b. Disinfection of wells:
- Chemical: Bleaching powder
The choice of purification methods depends upon the size of impurities/particles
Particle types Size of particle Purification methods
Dissolved 10-5
to 10-3
µm Precipitation
Adsorption
Colloidal 10-3
to 1 µm Chemical coagulations
Suspended or non-filterable 1 to 1000 µm Filtration
Sedimentation
Screening
Slow Sand and Rapid Sand Filtration
Slow Sand Filtration
Elements of a slow sand filter essentially consists of
i. Supernatant water
ii. Sand bed
iii. Under-drainage system
iv. A system of filter control
i. Supernatant water
- The supernatant water above the sand bed should be 1 to 1.5 meter
- The raw water during the waiting period of 3 to 12 hours, undergo partial purification by
sedimentation, oxidation and particle agglomeration.
ii. Sand bed
- The thickness of the sand bed should be about 1 meter.
- The effective diameter of the sand particle should be 0.2 to 0.3 mm
- The sand should be rounded, clean and free from organic matter.
- The sand bed is supported by a layer of graded gravel (30-40 cm deep)
- Water percolates through the sand bed very slowly (0.1 to 0.4 m3
/hr/m2
of sand surface) and it is
subjected to a no. of purification process such as mechanical straining, sedimentation, adsorption,
oxidation and bacterial action.
Vital layer
- This is slimy & gelatinous layer on sand bed which consists of thread like algae including planktons,
diatoms and bacteria.
- This layer is also called Schmutzdecke, zoogleal layer or biological layer.
- The formation of biological layer is known as “ripening of the filter”
- This is the heart of the filter.
- It removes organic matter, holds back bacteria and oxidizes ammoniacal nitrogen into nitrates.
- It helps in yielding bacteria free water.
iii. Under-drainage system

Year
- At the bottom of the filter is under-drainage system which consists of porous or perforated pipes,
which serves the dual purpose of providing an outlet for filtered water and supporting the filter
medium above.
iv. Filter control
- The filter is equipped with a valve for the purpose of maintaining a constant rate of filtration.
- Venturimeter is the regulation system which measure bed resistance
- When the bed resistance increases to maximum, the supernatant water is drained off and the sand
bed is cleaned by scrapping off the top portion of sand layer. The sand bed is again maintained to its
thickness and new filtration process is again begun.
Advantages of slow sand filtration
- It is simple to construct and easy to operate
- The cost of construction is cheaper than the rapid sand filter
- The physical, chemical and biological quality of water is very high
- It reduces bacterial count by 99.9- 99.99%
Disadvantages
- Filter occupies lot of space
- Initial cost is low but maintenance cost is much more than rapid sand filter
Figure: Slow Sand Filtration Process
Rapid Sand Filtration
Following steps are involved in the purification of water by rapid sand filter
i. Coagulation
- The raw water is first treated with a chemical coagulant such as alum.
- The dose varies from 5-40 mg/ltr, depending upon the turbidity and colour, temperature and pH value
of the water.
ii. Rapid mixing
- The treated water is then subjected to violent agitation in a mixing chamber for few minutes.
iii. Flocculation
- The water is then passed into the flocculation chamber where it is slowly agitated for 30 minutes,
which forms a thick copious, white flocculent precipitate of aluminium hydroxide.

Year
iv. Sedimentation
- The coagulant water is now led into sedimentation tank where it is kept for 2-6 hours.
- It removes 95% of the impurities and bacteria.
v. Filtration
- The partly clarified water is subjected to rapid sand filter.
- The filter consists of sand bed usually about 1 m thickness. The effective size of the sand is between
0.4-0.7 mm.
- Sand bed is supported by a layer of graded gravel 30-40 cm deep.
- The rate of filtration is 5-15 m3
/hr/m2
- As the filtration proceeds, the alum floc not removed by sedimentation is held back on the sand bed.
- It forms a slimy layer comparable to the zoogleal layer (in slow sand filter). It adsorbs bacteria from
the water.
- Oxidation of ammonia also takes place during the passage of water through the filter.
- As the filtration proceeds, the suspended impurities and bacteria clogs the filters. When the loss of
head approaches 7-8 feet, filtration is stopped and filters are subjected to process known as
backwashing.
Advantages of rapid sand filter
- Rapid sand filter bed occupies less space
- Filtration is 40-50 times rapid than that of slow sand filter
- The washing of the filter is easy
- There is more flexibility in operation
Disadvantages
- Requires chemical pre-treatment
- Relatively high skill operation is required
- Costlier
Figure: Rapid sand filtration process

Year
Contrast between rapid sand and slow sand filtration
Basis of differences Slow Sand Filtration Rapid Sand Filtration
1 Pre-treatment Not required except plain
sedimentation
Coagulation, Flocculation and
sedimentation
2 Filter media Sand Sand, or sand and anthracite coal, or
sand and anthracite coal and
coagulants
3 Filtration mechanism Biological action, straining, and
adsorption
Mechanical action
4 Cleaning method Scrapping and removing
Schmutzedecke and 1.5 to 3 cm
thick sand layer
Backwashing with or without
compresses air agitation
5 Cleaning interval Three to four months One to two days
6 Effective sand size 0.2-0.3 mm 0.4 -0.7 mm
7 Rate of filtration 0.1-0.4 m3
/hr/m2
5-15 m3
/hr/m2
8 Suitability For water supply to rural areas
and small town
For public water supply to town and
cities
9 Removal of bacteria 99.99% 99.9%
Disinfection of Water
Some of the commonly used methods of disinfection are
i. Chlorination
ii. Ozonation
iii. UV radiation
iv. Potassium permanganate
v. Iodine
vi. SODIS
Chlorination
Chlorination is a useful method for disinfection of water. It kills pathogenic bacteria but it has not effect on
spores and certain viruses (viral hepatitis) except in high doses.
Action of chlorine
- The disinfecting action of chlorine is mainly due to the hypochlorous acid, and to a small extent
due to the hypochlorite ions.
H2O + Cl2 → HCL +HOCl
HOCl → H + OCl
- The hypochlorous acid is the most effective form of chlorine for water disinfection.
- It is more effective (70-80 times) than the hypochlorite ion.
- Chlorine acts best as a disinfectant when the pH of water is around 7 because of predominance
of hypochlorous acid.
- When pH value exceeds 8.5, it is unreliable as a disinfectant because about 90% of the
hypochlorous acid gets ionized to hypochlorite ions.

Year
Principle of chlorination
- The water to be chlorinated should be free from turbidity. Turbidity impeded efficient chlorination.
- Chlorine demand of water should be estimated by calculating the difference between the amount of
chlorine added to the water and the amount of residual chlorine at the end of contact period.
- The contact period should be at least 60 minutes.
- The minimum concentration of free residual chlorine for drinking purposes should be 0.5 mg/ltr.
- The sum of chlorine demand of the specific water plus free residual chlorine of 0.5 mg/ltr gives the
correct dose of chlorine required to disinfect the water.
Disinfection of Well/Tank
The most effective method of disinfecting well or tank is by bleaching powder.
Steps in disinfection
- For disinfecting well/ tank we first measure the volume of water using either of the formula
For a circular well/ tank,
Volume of water =
3.14 × d2
× h
4
m3
of water
For a rectangular well/tank,
Volume of water = l×b×h m3
of water
- One cubic metre of water = 1,000 litres of water
- Roughly 2.5 grams of good quality of bleaching powder would be required to disinfect 1 m3
or 1000
litres of water. This will give an approximate dose of 0.7 mg of applied chlorine per litre of water.
- The required amount of bleaching water is placed in a bucket and made into a thin paste. More water
is added and stirred well and allowed to sediment. The supernatant solution of chlorine is then
transferred to another bucket discarding the lime.
- The bucket containing the chlorine solution is lowered some distance below water surface and
agitated.
- A contact period of one hour is allowed before the water is drawn for use.
Coagulants in Water Purification
Some commonly used coagulants include
- Aluminium Sulphate: Al2(SO4)3 .14H2O
- Ferrous Sulphate: FeSO4 .7H2O
- Ferric Sulphate: Fe2(SO4)3 .9H2O
- Ferric Chloride: FeCL3. 6H2O
- Calcium Hydroxide (Lime): Ca(OH)2
- Calcium Oxide: CaO
Mechanism of Action
Al2(SO4)3 + 3Ca(OH)2 → 2Al(OH)3 + 3CaSO4
Alum Lime Floc
Fe2(SO4)3 + 3Ca(OH)2 → 2Fe(OH)3 + 3CaSO4
Alum Lime Floc

Year
Types of commonly used coagulants
Coagulant Advantages Disadvantages Cost Comments
Alum (Aluminium
sulphate), alum
potash
Community use;
common; simple
technology
Difficult to optimize
without training
and equipment
Moderate Proper use
requires skill
Iron salts (ferric
chlorides or
sulphates
Same as alum Same as alum Moderate Proper use
requires skill
Lime, Lime+ soda
ash, caustic soda
Same as alum Same as alum; ph
control and
neutralization a
problem;
hazardous
chemical
Moderate to high Softeners; not
applicable to many
waters
Soluble synthetic
organic polymers
Improves
coagulation with
alum and iron salts
Same as alum;
hard to dose;
hazardous
chemicals
High Use with others
coagulants; limited
availability
Water Quality and Quantity Situation in Nepal
Water Quality
According to the report on Situation Analysis of Environmental Health in Nepal, 2009, Nepal has the
poorest drinking water and sanitation coverage in South Asia. The quality of drinking water from surface
as well as ground water sources is of growing concern in urban Nepal. Water quality of all the rivers and
streams of Kathmandu valley near to that of the densely populated areas exhibit characteristics similar to
that of raw sewage. Bishnumati, Dhobikhola also show similar characteristics to that of Bagmati. Water
quality of Seti river at Kaski, Budhi river at Morang and Phewa lake at Pokhara are polluted too.
The table below shows the bacteriological and chemical quality of drinking water sources in Kathmandu
valley. It is found that the values of selected chemical parameters lie within WHO guidelines, whereas the
values of selected bacteriological parameters are not within WHO guidelines; they are contaminated
either at source or at the points of consumption.

Year
Bacteriological water quality of different water sources, Kathmandu Valley
Parameters Water Sources WHO
Guideline
Value
Private Tap
Water
Public Tap
Water
Well Stone Spout
pH 6.5-8.2 6.5-7.5 7.5 7.5 6.5-8.5
Temp (0
C) 13-18 12-15 15-18 15-18 25
Iron (mg/l) ND-0.2 0.2 0.2 0.3 .03-3.0
N-NH4 (mg/l) ND-0.2 0.2 0.2 0.2 .004-0.4
PO4-P (mg/l) 0.1 0.1 0.1 0.1 0.4-5.0
Coliform
bacteria
(source points)
+/- + + + -
Coliform
bacteria
(consumption
points)
+ -
E. coli cfu/100
ml
10-131 3-20 48-200 58 0
Source: pradhan etl al. 2005
Further, the groundwater source for drinking water is also contaminated. Arsenic contamination is found
in some groundwater, water samples especially in deep tube wells.
The degraded quality of both surface water and groundwater in the valley is due to sewage, industrial
effluents, leechate from soild wastes, and infiltration of agricultural residue.
Water Quantity
- The surface water available in the country is estimated to be about 225 billion m3 per annum
- The estimated ground water potential in the Terai is 12 billion m3 of which 5.8 to 9.6 billion m3 could
be extracted annually (estimated recharge)
- The table below shows the total water availability and use by sectors in 2001.
Description 1995a
2001b
Total annual renewable water resource (km3
/year) 224 224
Per capita renewable water resource (000 m3
/year) 11 9.6
Total annual withdrawal (km3
/year) 14 18.5
Per capita annual withdrawal (000 m3
/year) 0.69 0.8
Withdrawal (%)
Domestic
Industry
Agriculture
3.8
0.3
95.9
3.6
0.3
96.1
Source a
UNEP 2001 and b
WECS 2004
- Further, the table below summarizes the water supply and demand condition within and outside
Kathmandu valley. To date 72% of the country’s total drinking water demand has been met. Each
year the drinking water demand grows and as a result, pressure on the existing output of water is
intense.
- The groundwater level in the Kathmandu valley is lowering due to excessive use for drinking
purposes. The groundwater level has lowered from 9 meters to as deep as 68 meters.

Year
Water quantity situation for water supply and water treatment plants
SN Description 2001
1 Production capacity million litres per day (mld) 228
Inside Kathmandu Valley (%) 58
Outside Kathmandu Valley (%) 42
2 Water demand (mld) 275
Inside Kathmandu Valley (%) 64
Outside Kathmandu Valley (%) 36
3 Average daily production 204
Inside Kathmandu valley 55
Outside Kathmandu Valley 45
Service levels
However, the National Water Supply and Sanitation Policy 2014, define the categories of service levels
as:
Service Indicators Service Level
High Medium Basic
Quanity (Ltrs per capita
per day
≥112 ≥65 ≥45
Quality Meets National Drinking
Water Quality
Standards
Meets National Drinking
Water Quality
Standards
Potable
Accessibility ≥75% consumers
having private taps
≥50% consumers
having private taps
≥75% of consumers
dependent on public
taps
Duration of supply
(hrs/day
24 (18-24 for system
performance evaluation
purposes)
24 (12-18 for system
purposes)
24 (6-12 for system
purposes)
Continuity (months/year) 12 12 (7 days of
interruption in a year
acceptable)
12 (7-14 days of
interruption in a year
acceptable)

Year
Concept of Water Sanitation and Hygiene
According to National Water Supply and Sanitation Policy 2014, water Sanitation Services refers to the
following:
- Storage, collection, transmission, and treatment of domestic, institutional, municipal/communal,
commercial, and industrial wastewater and disposal of treated wastewater in compliance with the
National Wastewater Discharge Quality Standards including the management of such services;
- Collection, transmission and disposal of gray waters from domestic, institutional, municipal/communal
and commercial sources in aesthetical and environmentally acceptable manner including the
management of such services;
- Solid waste management in order to minimize drinking water pollution and interference with the
wastewater management; and
- Health and hygiene promotion to maximize benefits of improved water supply and sanitation services.
Improved and unimproved water sources and sanitation facilities (Source WHO/UNICEF 2006)
Status Drinking water sources Sanitation Facilities
Improved • Piped water into dwelling plot or
yard
• Public tap/ standpipe
• Tube well/ borehole
• Protected dug well
• Protected spring
• Rainwater collection
• Flush or pour-flush to
Piped sewer system
Septic tank
Pit latrine
• Ventilated improved pit latrine
• Pit latrine with slab
• Composting toilet
Unimproved • Unprotected dug well
• Unprotected spring
• Cart with small tank/drum
• Bottled water
• Tanker-truck
• Surface waters (rivers, canals)
• Flush or pour-flush to elsewhere
• Pit latrine without slab or open pit
• Bucket
• Hanging toilet or hanging latrine
• No facilities or brush or field
Bottled water is considered improved only when the household uses water from an improved source for
cooking and personal hygiene.
Community Based Sanitation Approaches
i. Community Led Total Sanitation (CLTS) Approach
- Community Led Total Sanitation (CLTS) approach recognizes that individual hygiene behavior can
affect the whole community.
- CLTS in Nepal contributes to the Rural Water and Sanitation Policy 2004 of achieving total sanitation
by 2017 through community mobilization.
- The National Hygiene and Sanitation Guideline also recognized the importance of CLTS in achieving
open defecation free village.
Features of CLTS
- CLTS focuses on stopping open defecation rather then just building latrines.
- CLTS harnesses traditional collective community action to stimulate hygiene behavior changes.
- CLTS gives no subsidies to build latrines.
- CLTS promotes low cost homemade toilets made from local materials which are easily constructed by
the households themselves.

Year
Tools used in promoting CLTS
- Defecation area transect walk: to observe current situation
- Faeces mapping/ Social mapping: to establish information on community
- Faeces calculation: to estimate total amount of faeces produced by community annually.
- Defecation site visit
- Flagging in open defecation areas
- Seasonal calendar
ii. Participatory Hygiene and Sanitation Transformation (PHAST)
- It is a seven step participatory approach to promoting hygiene, sanitation and community
management of water and sanitation facilities.
- It builds on people’s ability to address and resolve their own problems and promote health
awareness.
- It aims to empower communities to manage their water and control sanitation related diseases.
- A key strategy of PHAST is helping people to rationally perceive the risk of adverse health
consequences associated with poor sanitation conditions and hygienic practices.
iii. SARAR Technique
- SARAR stands for Self-esteem, Associative strengths, Resourcefulness, Action-planning and
Responsibility: the five human qualities that the methodology seeks to promote.
- SARAR is a participatory methodology which has shown to be effective in enabling people to identify
their problems, plan for change and implement and monitor that change.
- SARAR techniques seek to foster discussions among households and communities.
- It uses visual materials and role play to facilitate the process.
Overall Scenario of Water Sanitation and Hygiene
Burden of diarrhoeal diseases due to poor water, sanitation and hygiene coverage
Global Burden
- Water, sanitation, and hygiene was responsible for 1,902,000 deaths from diarrhoeal disease in 2012
- In the world, an estimated 5.8% of total deaths are related to water, sanitation and hygiene (WASH)
- In WHO South-East Asian Region, a total of 994,000 deaths in 2004 were related to WASH. This
accounted for 7% of total deaths in the region.
- A total of 599,000 deaths in SEARO were due to diarrhoeal diseases which accounted for 60% of all
deaths due to WASH.
- In SEARO, the burden of diarrhoeal disease- 20,088,000 DALYs were attributable to WASH.
Nepal
- In 2012, the mortality rate of from diarrhea attributed to exposure to unsafe WASH services was 12.9
per 100,000 population.
- The burden of diarrhoeal disease- 459,000 DALYs are attributable to WASH (2004 data).
- In 2004, 9.3% of all deaths were related to WASH.

Year
Estimating Diarrhoeal disease burden related to WASH
# Example 1
Calculate the attributable fraction and disease burden in the given scenario:
Coverage by improved drinking water: 51%
Coverage by improved sanitation: 30%
Solution: First determine the population distribution for the exposure scenarios
Exposure scenarios Coverage Relative Risk (global average)
Improved water supply and
improved sanitation
(Scenario IV)
30% 6.9
Improved water and no improved
sanitation
(Scenario Vb)
51%-30% = 21% 8.7
No improved water supply and
no basic sanitation
(Scenario VI)
100%-51% = 49% 11
Now, process the data to calculate impact fraction:
Using the formula,
Impact fraction, 𝐼𝐼 𝐼𝐼 =
Σ𝑃𝑃𝑖𝑖 𝑅𝑅𝑅𝑅𝑖𝑖−1
Σ𝑃𝑃𝑖𝑖 𝑅𝑅𝑅𝑅𝑖𝑖
Where, Pi = Proportion of the population in exposure category i.
RRi = Relative risk at exposure category I compared to the reference level.
So,
𝐼𝐼 𝐼𝐼 =
(30% × 6.9 + 21% × 8.7 + 49% × 11)– 1
30% × 6.9 + 21% × 8.7 + 49% × 11
𝐼𝐼 𝐼𝐼 =
9.287 − 1
9.287
IF = 0.8923 = 89.23%
Further to calculate the disease burden attributable to WASH, the total disease burden for the population
(in deaths and DALYs) is multiplied by the impact fraction.
Suppose the total deaths is 5400 and DALYs 176000, then the disease burden attributable to WASH is
obtained as
Attributable burden (AB) = Impact fraction × total burden
= 0.8923 × 5400
= 4818.54 ≅ 4819 deaths
Therefore 4819 diarrhoeal deaths are attributed to WASH.
Also in terms of DALY,
Attributable burden (AB) = Impact fraction × total burden
= 0.8923 × 176000
= 157044.8 ≅ 157045 DALYs
This means, 157045 DALYs are attributable to WASH

Year
# Example 2 from past question (2072/12)
Calculate the attributable fraction of water and sanitation coverage of 60% and 40% respectively in the
burden of diarrhoeal disease (refer RR from any reliable study)
Solution: Here, we determine the population distribution for the exposure scenarios as follows:
Exposure scenarios Coverage Relative Risk (global average)
Improved water supply and
improved sanitation
(Scenario IV)
40% 6.9
Improved water and no improved
sanitation
(Scenario Vb)
60%-40% = 20% 8.7
No improved water supply and
no basic sanitation
(Scenario VI)
100%-60% = 40% 11
Here we have referred RR (global average) taken from previous studies.
Now, process the data to calculate impact fraction:
Using the formula,
Impact fraction, 𝐼𝐼 𝐼𝐼 =
Σ𝑃𝑃𝑖𝑖 𝑅𝑅𝑅𝑅𝑖𝑖−1
Σ𝑃𝑃𝑖𝑖 𝑅𝑅𝑅𝑅𝑖𝑖
Where, Pi = Proportion of the population in exposure category i.
RRi = Relative risk at exposure category I compared to the reference level.
So,
IF =
(40% × 6.9 + 20% × 8.7 + 60% × 11)– 1
40% × 6.9 + 20% × 8.7 + 60% × 11
IF =
11.1 − 1
11.1
IF = 0.9099 = 90.99%
Therefore, 91% of the diarrhoeal diseases are attributable to WASH.
Measures for prevention and control of Water borne diseases:
i. Basic Sanitation Measure
- Use of toilets
- Hand washing with soap during critical times
- Water and food hygiene
- Management of wastes
ii. Prevention measures
- Rota virus and measles vaccination
- Promotion of early and exclusive breastfeeding and vitamin A supplementation.
- Improved water supply in terms of quantity and quality, including treatment and safe storage of
household water.
- Community wide sanitation promotion
iii. Management
- Fluid replacement to prevent dehydration (Oral rehydration)
- Zinc treatment

Year
Immediate response strategy in emergency
i. Providing minimum quantity of drinkable water
- Chlorination of existing sources (wells, pump to bladders etc.)
- Provision of clean water containers.
- Protection of water sources (e.g pumps from wells)
- Fast distribution of treatment chemicals
ii. Protecting Existing Sources
- In an emergency, people are expected to settle at places where water is accessible easily. Therefore,
the first priority is often to protect these sources from pollution by people collecting this water.
- Protection measures can include:
• Banning washing or watering near the sources
• Piping water to a location away from the source
• Separating access points for people and animals

Year
Water and Sanitation Policies and Act/ Treaties Undertaken in Nepal
SN Act/ Regulation/ Policies/
Strategies
Areas Addressed
1 Constitution of Nepal 2015 • Establishes access to safe water and sanitation as a human
right:
• Article 35(4) states that every citizen shall have the right of
access to safe water and sanitation.
2 Water Resource Act 1992 • Umbrella act governing water resource management
• Declares the order of priority of water use
• Prohibits water pollution
3 Environment Protection Act
1996
• Requires certain persons/bodies to conduct EIA or IEE
• Deals with the prevention and control of pollution
4 National Drinking Water
Quality Standards and
Implementation Directives
2005
• Sets national parameters and guidelines for water quality
• Makes service providers responsible for monitoring water quality
standards.
• MOHP and its agencies made responsible for water quality
monitoring and surveillance.
5 Rural Water Supply and
Sanitation National Policy
2060 (2004) and Rural
Water Supply and
Sanitation National Strategy
2060 (2004)
• Aimed to set targets to provide safe, reliable and affordable
water supply with basic sanitation facilities to 100 percent of the
population on priority basis specially targeting the backward
people and ethnic groups, reduce water borne diseases and
save the time and labour of men, women and children from
fetching the water.
• The policy focused on massive renovation, rehabilitation,
improvement and expansion works of the existing system and
on increasing the quality of service.
6 Urban Water Supply Policy
2009
• The Policy sets the cost recovery principles, public private
partnership and sector effectiveness for improved service
delivery in proper perspectives according to the need of the day.
• The Policy had identified four major initiatives at the
implementation level:
o Small Towns Water Supply and Sanitation Sector Project
(STWSSSP);
o Kathmandu Valley Water Supply Sector Development
Program (KVWSSSP);
o Urban Environment Improvement Project (UEIP) and
o Integrated Urban Development Projects (IUDP)
7 Sanitation and Hygiene
Master Plan 2010
• Focuses to Open Defecation Free (ODF) with universal access
to toilet in both the urban and rural context through the total
sanitation approach.
8 National Water Supply and
Sanitation Sector Policy
2014
• Merges Rural Water Supply and Sanitation National Policy
(2004) and Urban Water Supply and Sanitation Policy (2009)
• Sets policies and strategies to ensure the availability of safe and
adequate water supply and sanitation services to all population.
9 Water Quality Surveillance
Guidelines 2070 BS
• Establishes roles of different agencies within MOHP with EDCD
as a focal point for water quality surveillance activities
• Sets guidelines for effective implementation of water safety plan.
• Identifies methods and processes for water quality surveillance

Year
UNIT 3: WASTE MANAGEMENT
Solid Waste Generation, composition and existing mechanism of its management
Generation of Solid Wastes
Study of Municipal Solid Waste Management in Nepal presents the following data on generation of solid
wastes
i. Generation of Household Solid Wastes
- The study for 58 municipalities shows that the average household waste generation was 170 g/per
capita/day
- The study also shows that the household waste generation rates varied depending on economic
status. Households with monthly expenditures of NRs40,000 ($417) and above generate 1.25
kilograms (kg)/household/day on average, which is more than twice as much as the 0.57
kg/household/day generated by households with monthly expenditures of less than NRs5,000 ($52)
- Terai municipalities generate the largest amount of per capita daily waste (0.88 kg/household/day).
ii. Generation of Institutional and Commercial Solid Wastes
- Study of solid waste generation in shops, hotels, and restaurants, shows an average waste
generation rate for commercial establishments as 1.4 kg per shop and 5.7 kg per hotel or restaurant.
- The average daily waste generation rate of schools and office are 4.0 kg and 1.4 kg respectively.
Summary:
- It is estimated that household waste in general contributes to about 50%–75% of the total municipal
waste generated.
- From the survey results, the average MSW generation can be estimated at 317 g/capita/day.
Composition of Solid Wastes
The characteristics of solid wastes collected from any area depend on various factors such as consumer
patterns, food habits, the cultural traditions of inhabitants, lifestyles, climate, and economic status. The
composition of solid wastes is changing with increasing use of packaging materials and plastics.
i. Composition of household solid wastes
- The average composition of household waste in municipal areas of Nepal can be classified in the
following categories
SN Waste categories Composition
1 Organic Waste 66%
2 Plastics 12%
3 Paper and paper products 9%
4 Glass, metals, textiles, rubber, leather and other wastes 13%
- The high organic content indicates a need for frequent collection and removal, as well as good scope
for organic waste resource recovery.
- The content of major reusable and recyclable materials (i.e., plastic, paper and paper products, metal,
glass, rubber and leather, and textiles) comprises 29% on average.

Year
ii. Composition of institutional wastes
- The solid wastes in office, schools and colleges are composed of the following wastes categories
1 Paper and Paper products 45%
2 Organic Waste 22%
3 Plastics 21%
4 Glass, metals, textiles, rubber, leather and other wastes 12%
iii. Commercial waste Composition
- The composition of waste from commercial establishments such as shops, hotels and restaurants are
as follows:
1 Organic Waste 43%
2 Paper and Paper products 23%
3 Plastics 22%
4 Glass, metals, textiles, rubber, leather and other wastes 13 %
Summary
- If all sources of solid wastes are combined, the average composition consists of organic waste (56%),
plastics (16%), paper and paper products (16%) and rest includes glasses, metals, textiles, rubber
and leather, etc.
Existing Mechanism of Solid Waste Management in Nepal
i. Collection and Segregation
- Various studies have found out that only about one third of households in the municipalities of Nepal
practice segregation of waste at source. This means that waste generate from about 70% of
households in municipalities goes to the stream for collection and disposal by municipalities in the
form of mixed waste.
- Even if waste segregation are done at sources, at many instances they are mixed again during
collection and transport due to the lack of separate collection and treatment methods.
- Citizens often dispose waste within or outside their compound either by unscientific compositng, open
burning, or throwing the waste in the surrounding open space.
- City cleaning and sweeping are irregular and often limited to main markets, main roads and some
residential areas.
- Container service, door to door collection and roadside pickup from open pile or containers are the
types of collection services generally practiced in municipalities.
ii. Transport and final disposal
- The wastes from primary collection are often transferred to processing centers or final disposal sites
in a vehicle (rickshaw, carts, tractors, dump trucks).
- The major problem in current solid waste system in Nepal is that sites for treatment facilities and
sanitary landfill have not yet been identified and wastes are currently being disposed of without
treatment in crude dumping sites.
- Open dumping, including riverside dumping and roadside dumping are most common practices of
waste disposal by many VDCs and municipalities.
- Only six municipalities in Nepal have a sanitary landfill.

Year
iii. Resource Recovery Methods
- The resource recovery activities such as recycling and composting are minimal in Nepal.
a. Recycling
- There are no formal system for reuse and recycle in VDCs and municipalities of Nepal.
- Small proportions of recyclable materials are recovered by households at source and sell them to
the household scrap collectors.
- Large amount of recyclable materials are disposed of on the streets.
- 32 municipalities in Nepal have waste minimization programs, such as reuse and recycling
activities via small entrepreneurs.
b. Composting
- Studies have found that only around 30% households in municipalities practice composting, most
of which are rural households and practice traditional composting methods.
iv. Special Waste Management
- Special waste includes categories of waste such as dead animals, construction and industrial waste,
and hazardous or infectious waste from health institutions
- For medical waste, incineration is practiced by hospitals in most municipalities.
- In some municipalities, medical waste is mixed with municipal waste, and in some cases it is burned
or crudely dumped.
- There are no proper systems for management of medical waste.
Types of hazardous wastes
Hazardous wastes are waste with potential to cause hazard to health and life of human beings. These
includes, cotton, gauze, soiled bandages, cotton used for dressing, blood bags, human and animal tissue,
body parts, chemicals, drugs, wastes generated by cleaning spills of hazardous waste, and any other
soiled materials that has been used for treatment.
Types of Hazardous Waste: See health care waste classification
Concept of Health Care Waste and its management status
Health-care waste includes all the waste generated by health-care establishments, research facilities, and
laboratories. In addition, it includes the waste originating from minor or scattered such as that produced in
the course of health care undertaken in the home (dialysis, insulin injections, etc.).
Classification of Health Care Wastes
Between 75% and 90% of the waste produced by health-care providers is non-risk or general health-care
waste, comparable to domestic waste. The remaining 10-25% of healthcare waste is regarded as
hazardous and may create a variety of health risks.
SN Waste Category Description and categories
1 Infectious Waste Waste suspected to contain pathogens
e.g. laboratory cultures, waste from isolation wards, tissues (swabs),
materials, or equipment that have been in contact with infected patients,
excreta

Year
2 Pathological Waste Human tissues or fluids
e.g. body parts, blood and other body fluids, fetuses
3 Sharps Sharp wastes
e.g. needles, infusion sets, scalpels, knives, blades, broken glass
4 Pharmaceutical
Waste
Waste containing pharmaceuticals
e.g. pharmaceuticals that are expired or no longer needed; items
contaminated by or containing pharmaceuticals (bottles, boxes)
5 Genotoxic Waste Waste containing substances with genotoxic properties
e.g. waste containing cytostatic drugs (often used in cancer therapy);
genotoxic chemicals
6 Chemical Waste Waste containing chemical substances
e.g. laboratory reagents; film developer; disinfectants that are expired or
no longer needed; solvents
7 Wastes with high
content of heavy
metals
Batteries, broken thermometers, blood-pressure gauges, etc.
8 Pressurized
containers
Gas cylinders, gas catridges, aerosol cans
9 Radioactive wastes Waste containing radioactive substances
e.g. unused liquids from radiotherapy or laboratory research,
contaminated glassware, packages or absorbent paper, urine and
excreta from patients or tested with unsealed radionuclides, sealed
sources
Health care waste management in Nepal
- A study by ENPHO on Health care waste management practices in selected hospital of Kathmandu in
2001 has found out an average health care waste generation of 1.7 kg/person/day and 0.48
kg/person/day of Health care risk waste (HCRW) at an average bed occupancy rate of around 65%.
- Many studies have revealed that majority of health care institutions do not practice safe waste
handling, storage and disposal methods.
- A survey report on solid waste management in Nepal by ADB in 2012 suggests that incineration is
practiced for medical waste by hospitals in most municipalities, although this essentially involves
merely burning the waste in a chamber or open burning in the hospital compound.
- In some municipalities, medical waste is mixed with municipal waste, and in some cases it is burned
or crudely dumped.
- In Kathmandu, Bir and a few other hospitals have started managing all types of hospital waste in a
safe manner.
- In Nepal, health care waste management guideline was prepared by NHRC in 2008 to guide the
management of health care wastes.
Management of Health Care Wastes (Based on HCW management guidelines, Nepal)
i. Waste Minimization
a. Reduction
- Reduction can be achieved through product substitutions, modifications and procedural changes
- Organic pigments should replace heavy metals pigments, commonly used for coloring waste
bags and sharp containers.
- There are many examples of product changes; e.g. change from solvent based products to water
based or lead based paints to less hazardous alternatives.

Year
b. Reuse
- Reusable items should be used preferred whenever it is clinically appropriate. E.g use of
washable nappies, crockery, reusable kidney dishes, etc.
c. Recycle
- A large number of recyclable items are generated by health care institutions and should be
separated for recycling.
ii. Waste Segregation
- Every health care institution should mandatorily segregate wastes at source into sharps, hazardous
and general wastes.
- It is highly recommended that all health care institutions recycle their general waste into organic and
non-organic waste. In such case separate bins should be used to collect organic and inorganic
wastes.
- Applicable wastes should be composted or recycled within the health care institution premises or sent
to treatment sites.
- General wastes should be treated as municipal waste and sent for landfilling
iii. Waste collection and transportation
- Wastes should be collected daily by sanitary staffs and sweepers and waste collection bags should
be labeled appropriately before transportation.
- Yellow bagged hazardous waste and black bagged general waste should be collected and
transported separately.
iv. Waste Storage
- A separate central storage facility should be available for yellow bagged hazardous waste. These
wastes should be stored for no more than 24 hours before transporting for incineration.
- Containers with radioactive waste shall be stored in a specially marked area in a lead-shielded
storage room.
v. Waste treatment and disposal
- Several methods are used for health care waste treatment depending on the type of waste material.
- These treatment methods include
 Incineration – For Sharps, infectious, pathological and pharmaceutical wastes, etc.
 Chemical disinfection- For infectious wastes and sharps
 Autoclaving – For sharps
 Encapsulation- For sharps and pharmaceutical wastes
 Sanitary landfill- For infectious wastes and small quantities of pharmaceutical wastes
 Inertization- For pharmaceutical and cytotoxic wastes
- The choice of treatment system should be made carefully, on the basis of various factors.
- All sharps should be treated separately. Syringes and needles should be destroyed using a needle
destroyer and burnt in a tiny pit. The remains of hard mass should be disposed of as general waste.

Year
UNIT 4: FOOD
Concept of Food Security
Food security exists when all people, at all times, have physical and economic access to sufficient safe
and nutritious food the meets their dietary needs and food preference for an active and healthy life.
(World Food Summit, 1996)
From this dimension, four main dimensions of food security can be identified
Physical Availability - Food availability addresses the supply side of food security and is determined by
the level of food production, stock levels and net trade
Economic and
physical access to
food
- An adequate supply of food does not guarantee household level food security.
- Income, expenditure, market prices, buying capacity of households or individuals
is also concerned to food security
Food utilization - Utilization is commonly understood as the way the body makes the most of
various nutrients in the food.
- Sufficient energy and nutrient intake by individuals is the result of good care and
feeding practices, food preparation, diversity of the diet and intra-household
distribution of food.
- Combined with good biological utilization of food consumed, this determines the
nutritional status of individuals.
Stability of the other
three dimensions
over
time
- Even if one’s food intake is adequate today, it may still be considered as food
insecurity if there is inadequate access to food on a periodic basis, risking a
deterioration of nutritional status.
- Adverse weather conditions, political instability, or economic factors
(unemployment, rising food prices) may have an impact on food security status.
Food Quality Situation of Nepal
- Many food products available in the market are without appropriate food labels.
- In 2011, food adulteration rate in Nepal was 15.6%. Some of the adulterated food items identified by
DFTQC are listed in the table below
- Processed drinking water, processed milk and refined oil are the major sub-standard food products
available in the market.
- Various forms of non-edible and non-permitted colors like metanil yellow, orange G., etc. are used in
sweets and food items.
- Further, the hygienic condition of street foods is very poor. Studies have shown higher coliform
counts in street foods indicating poor food quality,
- Department of Food Technology and Quality Control is responsible for execution of food legislation in
Nepal.
- Existing food legislation is not adequate to address the present day realities of food safety issues,
because
• It is not directed by the risk assessment principles.
• Human resource in food quality control is inadequate.

Year
Types of food items and their adulterants
Food items Adulterants
Edible oils Rapeseed oil, linseed oil, soybean oil and in some cases free fatty acid
Ghee Vegetable ghee, palm oil, free fatty acid
Spices Foreign matter, volatile oil low
Grains Foreign matter like sand, gravel, straw, stems, damaged grain or insect-infested
grains beyond permissible limit.
Sweets Non-edible color
Milk Presence of extraneous water, starch, fact and deficiency in fat and non-fat solids
Flour Excess of bran, foreign starch, chalk powder
Food Borne Diseases
A food borne disease has been defined by WHO as “any disease of an infectious or toxic nature caused
by or thought to be caused by the consumption of food or water”.
Food borne diseases can be classified into two broad categories:
i. Food Borne Infection:
- A food borne infection is caused by ingestion of food contaminated by viruses, bacteria or parasites:
- Symptoms of infection usually include diarrhea, nausea, vomiting and abdominal cramps. Fever is
often associated with infection.
- Some of the major food borne infections are listed in the table below:
Category Infections
Bacterial Typhoid fever and paratyphoid fever
Other Salmonella infections
Clostridium perfringes illness caused by enterotoxin released by Clostridium
perfringes
Bacillus cereus gastroenteritis caused by enterotoxin released by Bacillus cereus
Bacillary dysentery(shigellosis)
Anthrax, brucellosis, tuberculosis
Viral and rickettsial Infectious hepatitis
Q Fever
Protozoal Amoebic dysentery
Zooparasitical Taeniasis, ascariasis, etc.
ii. Food Borne Intoxication:
- A food borne intoxication is caused by ingestion of food already contaminated by a toxin.
- Some of the major food borne intoxications are listed in the table below:
Sources Intoxications
Bacterial origin Botulism caused by toxin produced by Clostridium botulinum
Staphylococcal enterotoxin food poisoning caused by toxin produced by S.
aureus
Food borne intoxications
due to chemical poisons
Intoxications caused by fish (shellfish) and plant toxins (e.g. wild
mushroom)
Intoxications caused by inorganic and organic compounds in food
Fungal Mycotoxicosis, Ergotism
Genetically Modified Foods Food allergies, antibiotic threats, cancer, etc.

Year
Factors affecting microbial growth
i. Availability of nutrients: Water, energy source, nitrogen, vitamins and minerals.
ii. Temperature: Depends on type of bacteria; psychrophilic (0-250
C), mesophilic (30-400
C) or
thermophilic.
iii. Acidity/pH: Optimal pH for microbial growth is 6.0 to 8.0.
iv. Available water (Water activity): Foods having water activity of -.85 or above support microbial
growth.
v. Oxygen (air): Depends on whether aerobic (E. coli) or anaerobic (clostridium botulinum)
vi. Time
Role of water activity in food security
Water activity is a measure of how efficiently the water present can take part in a chemical & physical
reaction).
Water activity ranges from zero (water absent) to 1.0 (pure water).
Roles of water activity
- The concept of water activity is very useful in food preservation and on the basis of water activity
many preservation processes can be successfully adapted.
- Water activity can determine a food’s shelf stability. It can predict which microorganism will be
potential sources of spoilage.
- Stability and food security depends on water activity in the food environment. The products with
higher water activity are perishable and insecure for long-term use.
- By measuring and controlling the water activity in food, it is possible to maintain the chemical stability
of food.
- Water activity is an important factor affecting the stability of powders and dehydrated products during
storage.
Mycotoxins
Mycotoxins are poisonous chemical compounds produced by certain fungi. Since they are produced by
fungi, mycotoxins are associated with diseased or mouldy crops, although the visible mould
contamination can be superficial.
- Mycotoxins occurring in food have a great significance in the health of humans and livestock.
- The effects of some food-borne mycotoxins are acute, symptoms of severe illness appearing very
quickly. Other mycotoxins occurring in food have longer term chronic or cumulative effects on health,
including the induction of cancers and immune deficiency.
- There are five mycotoxins, or groups of mycotoxins, that occur quite often in food:
deoxynivalenol/nivalenol; zearalenone; ochratoxin; fumonisins; and aflatoxins.
- The food-borne mycotoxins likely to be of greatest significance for human health in tropical
developing countries are the fumonisins and aflatoxins.
Mycotoxin Commodity Health effects
Deoxynivalenol/ nivalenol Wheat, maize, barley Human toxicoses
Zeralenone Maize, Wheat Identified by IARC as a possible human
carcinogen.
Affects reproductive system in pigs and
livestock
Ochratoxin A Barley, wheat and many
other commodities
Suspected by IARC as human carcinogen

Year
Fumonisin B1 Maize Suspected by IARC as human carcinogen
Aflatoxin B1, B2 Maize, peanuts and many
other commodities
Chronic exposures can lead to liver
inflammation, liver cirrhosis, immune
deficiency, etc.
Aflatoxin B1and naturally occurring mixtures
of aflatoxins, identified as potential human
carcinogens.
Aflatoxin B1, B2, G1, G2 Maize, peanuts
Prevention and control of mycotoxin
i. Primary prevention
- Controlling field infestation of planting crops by fungi.
- Making schedule of suitable pre-harvest, harvest and post-harvest.
- Lowering moisture content of plant seeds after post-harvesting and during storage.
- Storing commodities at low temperature whenever possible.
- Using approved fungicides and preservatives against fungal growth.
ii. Secondary prevention
- Stopping the growth of infested fungi by re-drying the products.
- Removal of contaminated seeds by manual picking and sorting.
- Proper storage of products such that the conditions are not favorable to fungal growth.
iii. Tertiary prevention
- Complete destruction of contaminated products.
- Detoxification or destruction of mycotoxins to the minimum level.
Measures of improving food safety
- Public awareness of food safety and hygiene
- Food labeling
- Legal measures
Legal provisions of food quality
i. Food Act,1965
- The objective of the Food Act is to safeguard the health and well being of the consumers, to prevent
adulteration of food stuffs with undesirable elements or to prohibit the change of any originalities of
food and to maintain the quality standard of food.
- The main features of the act are
• Definition of food, sub-standard and adulterated food,
• Prohibition on the production, sale, export and import or keeping of any adulterant and on the
sale of falsely stated or misbranded products.
• Licensing for manufacturing, selling, distributing, storing or processing of food.
• Penal provisions: The punishment has been graded to be inflicted as per the nature of violation.
ii. Nepal Quality Standard (Quality Mark) Act 1980
- Nepal Bureau of Standards and Metrology fixes the quality standards for the products and assign
quality marks to the branded products.

Year
- Nepal Quality Standard Act specification lies usually above the minimum quality standards. NS mark
is meant for the purpose of providing a third party guarantee to the consumers.
iii. Municipality Act 1991
- This act has provisions to ban products harmful to human health, to prevent sales of meat of
diseased animals and to make arrangements for hygienic distribution.
iv. Other legal provisions
- Consumer protection Act 1998 and Rules 2000
- Slaughterhouse and meat inspection act 1998 and rules 2000
- Animal health and livestock service act 1998 and rules 2000
- Pesticide regulation act 1991
- Breastfeeding substances (sales & distribution control) act 1992 and rules 1994

Year
UNIT5: AIR POLLUTION AND ITS IMPACT
Status of Air Pollution in Indoor and Outdoor Levels
Status of Indoor Air Pollution
Indoor Air Pollution (IAP) refers to the physical, chemical, and biological characteristics of air in the indoor
environment within a home, building, or an institution or commercial facility. Indoor air pollution is a
concern in the developed countries, where energy efficiency improvements sometimes make houses
relatively airtight, reducing ventilation and raising pollutant levels
Global Status of indoor air pollution
- According to WHO, 4.3 million deaths were attributable to household air pollution in 2012.
- The South East Asian region bears most of the burden with 1.69 million deaths.
- In the year 2004, indoor air pollution from solid fuel use was responsible for almost 2 million annual
deaths and 2.7% of the global burden of disease (in Disability-Adjusted Life Years or DALYs). This
makes this risk factor the second biggest environmental contributor to ill health, behind unsafe water
and sanitation.
- In low income countries, indoor air pollution is responsible for up to 4.0% of the burden of disease
- Every year, indoor air pollution is responsible for nearly 900,000 deaths due to pneumonia among
children under five years of age.
Nepal
- According to the 2011 NDHS, 71 percent of households cook inside the house. About 66%
households of Nepal use solid fuel as primary source of energy. Use of these fuels is more common
in rural areas. So, it can be assumed that there is substantial burden of disease attributable to indoor
air pollution.
- In the 2011 survey the neonatal mortality rate among babies born in a household with indoor air
pollution was higher (at 37 deaths per 1,000 live births) than among babies born into a household
without indoor air pollution (at 27 deaths per 1,000 live births).
- A study conducted by NHRC in 2004 reveals that the indoor PM10 concentration is 2418 μg/m³ in
houses with traditional clay stoves using solid bio-fuel. Whereas, the PM10 concentration level in
kitchens using cleaner fuels (gas, kerosene) was found to be 792 μg/m³, which was about three times
lower (NHRC/WHO 2004).
- A study done by NHRC/WHO in 2008 revealed that the about 50% cases of acute lower respiratory
infections (ALRI) were attributed by indoor smoke in Dhading district and total Disability Adjusted Life
Years (DALYs) was1284 due to ARI.
- World Bank (2008) study estimated that the total cost of indoor air pollution is US4 147.3 million
which is almost 2% of Nepal’s GDP
Status of Outdoor Air Pollution
Outdoor air pollution is the condition of air in the outdoor environment that directly affects the health of the
humans and ecosystems. Outdoor pollution primarily results from the combustion of fossil fuels by
industrial plants and vehicles. This releases carbon monoxide, sulfur dioxide, particulate matter, nitrogen
oxides, hydrocarbons and other pollutants.

Year
Global Status of Ambient Air Pollution
- In 2014, 92% of the world population was living in places where the WHO air quality guidelines levels
were not met.
- Ambient (outdoor air pollution) in both cities and rural areas was estimated to cause 3 million
premature deaths worldwide in 2012.
- Some 88% of those premature deaths occurred in low- and middle-income countries, and the
greatest number in the WHO Western Pacific and South-East Asia regions.
- WHO estimates that in 2012, some 72% of outdoor air pollution-related premature deaths were due to
ischaemic heart disease and strokes, while 14% of deaths were due to chronic obstructive pulmonary
disease or acute lower respiratory infections, and 14% of deaths were due to lung cancer.
Nepal
- Background levels of some representative PAH in the air are reported to be 0.02-1.2 nanograms per
cubic meter (ng/m3
) in rural areas and 0.15-19.3 ng/m3
in urban areas. (Chen et al. 2015)
- Mortality rate attributed to household and ambient air pollution is 104.2 per 100,000 (2014).
- The air quality deteriorates drastically during the dry period (December-May), and improves during
the wet period (June-November). During December, January and February, the 24 hour average
concentration of PM10 exceeds the NAAQS of 120 μg/m³ almost everyday at the urban area stations
(Pulchowk, Ratnapark, and Putalisadak).
- In 2005, the Ministry of Population and Environment estimated that ambient air pollution was
responsible for up to 1,600 premature deaths in the Kathmandu Valley.
- A NHRC/WHO study based on the Environmental Burden of Disease (EBD) approach, estimated
1,926 cases of premature death per year (NHRC/WHO, 2009).
- The World Bank estimated that Nepal’s annual health cost attributed to urban air pollution was USD
21 million in 2007, equivalent to 0.29% of the GDP.
Why is Kathmandu Valley Vulnerable to Air Pollution?
- The unique topographic features coupled with high emissions of pollutants make the valley
particularly vulnerable to air pollution.
- The valley is surrounded by hills forming
bowl-shaped topography, which restricts wind
movement and retains the pollutants in the
atmosphere.
- This is especially bad during the winter
season (Nov- Feb) when thermal inversion
occurs in the valley late night and early
morning.
- Cold air flowing down from the mountains is
trapped under a layer of warmer air and acts
as a lid. As a result, the pollutants are trapped
close to the ground for extended periods of
time. Atmospheric inversion over Kathmandu Valley during winter

Year
Major Sources of Air Pollution
The major sources of ambient air pollution in Nepal, particularly urban centres (e.g. Kathmandu) include:
i. Mobile Sources
- Vehicle exhausts
- Road dust re-suspension
ii. Stationary Sources
- Industrial / commercial fuel
- Domestic fuel combustion
- Brick kilns
- Cement factory
- Stone crushers
- Industrial boilers
Types of Pollutants
On the basis of origin, pollutants are classified as primary and secondary pollutants:
i. Primary Air Pollutants
- Primary air pollutants are those that are emitted into the atmosphere from a source such as a factory
chimney or exhaust pipe, or through suspension of contaminated dusts by the wind.
- In principle, therefore, it is possible to measure the amounts emitted at the source itself.
Pollutants Sources Health Effects
1 Oxides of Sulphur
(SOx)
Fossil fuel combustion (power
plants), industrial boilers,
household coal use, oil refineries
- Lung impairment and respiratory
symptoms
- Precursor to particulate matter
- Contributes to acid precipitation
2 Oxides of Nitrogen
(NOx)
Anthropogenic: Fossil fuel
combustion (vehicles, electric
utilities, industry), kerosene
heaters,
Natural: Lightening and biologic
processes in soil
- Decreased lung function
- Increased respiratory infection
- Precursor to ozone
3 Carbon Monoxide
(CO)
combustion mainly from motor
vehicles
- Interferes with delivery of oxygen
- Fatigue, headache and dizziness
- Neurological damage
4 Volatile Organic
Compounds (VOCs)
– e.g. benzene,
toluene
Solvents, glues, smoking, fuel
combustion, forest fires
- Associated with range of effects
(depending on the compound)
- Irritation of respiratory tract
- Nausea and cancer
5 Particulate matters Automobile & vehicle exhaust,
fuel burning (wood stoves,
fireplaces), power plants and
industry
- Increased infant respiratory mortality
- Reduced lung function
- Elevated symptoms in asthmatics
6 Carbonaceous
Particles
Combustion sources (vehicles,
utilities, industrial boilers
- Lung toxicity
- Premature mortality
- Important precursor to particulate
matter
7 Non-carbonaceous
primary particles
Fly-ash, mechanical processes,
construction and demolition
- Lung impairment
- Elevated symptoms in Asthmatics

Year
ii. Secondary Air Pollutants
- Secondary air pollutants are those formed within the atmosphere itself.
- They arise from chemical reactions of primary pollutants, possibly involving the natural components
of the atmosphere, especially oxygen and water.
- The most familiar example is ozone, which arises almost entirely from chemical reactions that differ
with altitude within the atmosphere.
Pollutants Sources Health Effects
1 Ground Level Ozone Product of photochemical
reaction between VOC and
NOx
Reduced lung function
respiratory symptoms, such as coughing
and shortness of breath, Worsening of
asthma and other lung diseases
2 Nitrogen Compounds
(NO2 and HNO3 formed
from NO
Combustion processes
(heating, power generation,
and engines in vehicles)
- Contributes to acid precipitation
- Contributes to photochemical smog
3 Secondary Particulate
Matter
i. Sulphates and
nitrate aerosols
ii. Secondary Organic
Aersols
Chemical and physical
processes in the atmosphere
(oxidation of VOCs, oxidation
of SO2 and NOx
- Severity of respiratory symptoms
- Cardiovascular effects
Types of Indoor Air Pollutants and Its Impact
Some of the major indoor air pollutants and their impacts have been discussed below
SN Pollutants Health Effects
1 Benzene - Acute myeloid leukemia (sufficient evidence on causality)
- Genotoxicity
2 Carbon monoxide - Acute exposure-related reduction of exercise tolerance and increase in
symptoms of ischaemic heart disease
3 Formaldehyde - Sensory irritation
4 Naphthalene - Respiratory tract lesions leading to inflammation and malignancy
5 Nitrogen dioxide - Respiratory symptoms, bronchoconstriction, increased bronchial
reactivity, airway inflammation and decrease in immune defense, leading
to increased susceptibility to respiratory infection
6 Polycyclic aromatic
hydrocarbons
- Lung cancer
7 Radon - Lung cancer
- Suggestive evidence of an association with other cancers, in particular
leukemia and cancers of the extrathoracic airways
8 Trichloroethylene - Carcinogenecity (liver, kidney, bile duct and Hodgkin’s lymphoma
9 Tetrachloroethylene - Effects in the kidney indicative of early renal disease and impaired
performance.

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