Brief ideas about the heavy metals and their poisoning. Actual reasons behind their pollution and contamination. Which type of disease occurred by their exposure. Real scenario of the Bangladesh by the contamination and pollution of heavy metals through their exposure

1. Heavy Metal Poisoning

2. What are Heavy Metals?
Heavy metals are naturally occurring elements that have a high atomic
weight and a density at least 5 times greater than that of water (specific
gravity of more than 5gm/cm3).
They have a relatively high density and are toxic or poisonous at low
concentrations.
Heavy metal pollution can originate from natural and anthropogenic
sources
Heavy metal poisoning is caused by the accumulation of certain metals
in the body due to exposure through food, water, industrial chemicals, or
other sources.

3. Why Heavy Metals are
Poisonous?
Heavy metals are dangerous because they tend to bio-accumulate.
Bio-accumulation means an increase in the concentration of a
chemical in a biological organism over time, compared to the
chemical's concentration in the environment. Compounds
accumulate in living things any time they are taken up and stored
faster than they are broken down (metabolized) or excreted.

4. How are people exposed to Heavy
Metals?
• Heavy metal contamination may occur due to factors
including irrigation with contaminated water, the addition
of fertilizers and metal based pesticides, industrial
emissions, transportation, harvesting process, storage
and/or sale
• People may be exposed to small amounts of heavy metals
through food, water, air, and commercial products. People
can also be exposed in their workplace, as several
industries use or produce these metals. If these metals
accumulate in the body in concentrations sufficient to
cause poisoning, then serious damage may occur.

5. List of
Heavy
Metals
Al
As
Ba
Cd
Cs
Hg
Pt
Sn
Th
U
Cu
Ni

6. Chronic Effect of Heavy Metals:
 CNS/PNS: predominate
 Heme: anemias, cytopenias
 Renal: CRI/CRF
 CA: Various
 Skin: Rashes, colored lines
on nails/gums

7. Acute Effect of Heavy Metals:
 GI: Nausea/vomiting/diarrhea-most metal
ingestions
 Renal: Proteinuria, aminoaciduria, ATN
 CV: Response to volume loss, dysrhythmia,
congestive CM
 CNS: dMS; periph neuropathies in hours to days
 Hair/skin/nail changes: lag days –wks behind acute
exposure

8. Acute and chronic effect of Arsenic (As)
Acute Effect Chronic Effect
Occurs form accidental ingestion of
pesticides and less commonly suicidal
attempts
Multisystem disease : malignancy
Respiratory Effect: Respiratory failure and
pulmonary edema
Anaemia , leukopenia , Thrombocytopenia
GI Effect: nausea, vomiting, colicky
abdominal pain, and profuse watery
diarrhoea.
Cutaneous changes: initial persistent
erythematous flush slowly, over time, leads to
melanosis, hyperkeratosis, and desquamation
Hematological abnormalities:
haemaglobinuria, intravascular
coagulation, bone marrow depression,
severe pancytopenia,
non-specific symptoms : abdominal pain,
diarrhoea, and sore throat.
Renal Effect: Renal failure Interference of Anemiawith folate
metabolism and DNA synthesis may result in
megaloblastic changes.

9. Acute and chronic effect of Chromium (Cr)
Acute Effect Chronic Effect
Primary target : The respiratory tract Inflammatory changes in the respiratory tract
due to chromium (III) salts
Occupational asthma in sensitized
individuals
Nasal septum ulceration and perforation,
respiratory irritation, lung cancer and possible
renal effects by chronic inhalation of high level
of chromium (VI)
Hepatic damage Chronic dermal exposure can result in deeply
penetrating skin ulcers
Cardiovascular, gastrointestinal damage
due to ingestion of large amount of
Chromium
Chromium (VI) compounds have mutagenic
potential
Potentially death Chromium (VI) compounds are carcinogenic to
humans and Potassium dichromate may be toxic
to the reproductive system and the developing
fetus.

10. Acute and chronic effect of Lead (Pb)
Acute Effect Chronic Effect
This is rare . Many reported cases of
acute poisoning may be actually be
exacerbations of chronic lead poisoning
when significant quantities of lead are
suddenly released into the bloodstream
from bone.
MILD TOXICITY (BL 40 -60 mcg/100m1) :
Fatigue ,Irritability ,Abdominal discomfort
GI effect: constipation or diarrhea(black
stool) , vomiting
MODERATE TOXICITY (BL 60-100
mcg/100m1): Arthralgia ,Headache, Tremor
,Muscular exhaustibility, Diffuse abdominal
pain ,Anorexia, metallic taste, vomiting ,
Weight loss ,Hypertension , Constipation
CNS effect: hyperactivity or lethargy
ataxia , behavioral changes ,convulsions
SEVERE TOXICITY (BL more than
100mcgiml) :Lead palsy: wrist or foot drop ,A
bluish black lead line on gums, Lead colic :
severe - abdominal cramps, Lead
encephalopathy .
Other effect: metallic taste ,abdominal
pain

11. Acute and chronic effect of Mercury (Hg)
Acute Effect Chronic Effect
Local Effects -
Oral ingestion (chiefly inorganic salts)
gastrointestinal: pain, vomiting, diarrhea,
hemorrhage Inhalation: Pneumonitis,
metal fume fever (Hg0)
Classic symptoms: tremor, gingivitis, erythrism
(Greek erethismos = irritate)
Systemic Effects - Shock Kidney
(inorganic salts) CNS: lethargy, (shock
related effects) Metallic taste, sore gums,
salivation
Renal & CNS damage
Minamata disease - neurological syndrome
caused
by severe mercury poisoning

12. Arsenic contamination in Bangladesh
 Arsenic contamination of ground water is a major public health
concern in Bangladesh
 Chronic toxicity of arsenic in humans from arsenic contaminated
drinking water occurs in 61 of 64 districts in Bangladesh. The
maximum permissible level of arsenic in drinking water is 10 µg/L
(WHO, 2008) and in Bangladesh, it has been adjusted to 50µg/L
by the local authorities
 A survey showed that arsenic related diseases resulted in 9136
deaths per year and 174 disabilities
 In Bangladesh, raw rice contains higher concentration of arsenic
compared to raw vegetables
Heavy Metal Poisoning According to Bangladesh Aspect

13. Lead contamination in Bangladesh
 A study with fish and water of Turag river found high lead in water samples
(0.1169±0.041 ppm) (Maximum allowable concentration is 0.05 ppm) and Lia
fish (3.8656 ± 1.041 mg/kg) (FAO standards-0.10 mg/kg
 Another study with samples from central market of Rajshahi, Bangladesh
found high Pb in fish "Major carp"
 A study by BRRI showed that one sample of rice collected from industrial field
of Narayanganj district have a very high amount of lead (0.242ppm)
 Another study with water and plants samples from area around Tejgaon
industrial area found the level of Pb to be much higher than the permissible
levels of WHO and USPH standard.
 A study in Jessore district found high lead level in vegetables like ghotkol,
elephant foot, bottle ground leaf and stem amaranth (1.689, 0.967, 0.987 and
0.831 µg/g respectively).

14. Mercury contamination in
Bangladesh
 It is estimated that the release of mercury from the 33 cement factories of
Bangladesh is 0.56265 million tonnes. A total of 1.44 million tonnes mercury is
released per year from paper and pulps mills in Bangladesh.
 Based on the same ESDO survey, 1.09 -6.22 million tonnes
mercury vapour is released from mercury amalgam fillings per year from
dental sector in Bangladesh.
It is estimated that potential mercury emissions from the energy sector is
3058.158kg.
 Besides, mercury release from CFL light bulb is 0.118 million tonnes. Also
Mercury release from jewellery sector was estimated to be 4.1 million tonnes.
 Bangladesh has no specific guidelines regarding the management of mercury
disposal or how to safely manage the use of products or equipments that
contains mercury or mercury compounds.

15. Chromium contamination in
Bangladesh
 In Bangladesh, among the routes of chromium eco-toxicity, feeds
and fertilizer production from tanned skin cut wastes is the most
direct one leading to food chain contamination
 A study by Bangladesh livestock research institute (BLRI) found
high chromium (0.53 to 0.96 ppm) in all milk samples of both
brand and local vendors compared to the IAEA values (0.22 to
0.29ppm)
 A study with "Stinging Catfish" of Turag river of Dhaka found
high chromium (1.46mg/Kg) in fish body
 A study with vegetable samples grown at Gazipur district showed
that the concentration of chromium (21.9-22.9µg/g) was higher
than the maximum allowable level (WHO-1.3µg/g)

16. Heavy Metal Pollution of River
Water
 In the Buriganga river fish, water and sediment are being contaminated by
industrial wastes, municipal wastes and pesticides . The heavy metal
concentrations (Pb, Cr, Mn, Co, Ni, Cu, Zn, As, and Cd) in water and sediment
were very high and in most cases, exceeded permissible limits recommended by
the Bangladesh government and other international organizations.
 The Turag River near Dhaka city is being severely polluted by industrial waste
waters and urban sewage from the Tongi municipal and industrial area. Cr, Cu,
Zn belongs to the category of moderately to highly polluted. The amount of Mn,
Fe and Cd exceeded the allowable limit set by WHO
 There are many industries close to the Karnafully river bank without any waste
management system.
Heavy metals were found above the permissible limit in pore water of salt
marsh along the Karnafully river coast.
Cd exceeded the recommended values and deliberates little sign of presence of
metal pollution in the Karnafully River.
There is a higher concentration of Pb in Chapila fish..

17. Heavy Metal Pollution of River
Water
 The Meghna river is also polluted with heavy metals because of
rapid urbanization and industrialization. The water, sediment and
fishes of the Meghna river contaminated with heavy metals. Pb
and Zn concentrations were found above the permissible limit in
15 fishes. The concentrations of Cd, Cr, Mn and Zn in the Meghna
river water are lower but Fe is higher than standard guidelines
 Due to the geographical location of the Shitalakshyaa river,
various metals were found in excess amount. The amount of Al,
Cd and Mn exceeded the recommended value set by WHO. The
concentrations of Pb, Fe, Cu and Zn were found below the
permissible limit. The concentrations of heavy metals (Cd, Cr, Ni,
Pb and Zn) are extremely higher than Bangladesh standard for
drinking water.

18. Heavy Metal Pollution
City Area
 In Dhaka, Kushtia, Gazipur, Savar,
Mymensingh, Bogra and Chittagong ,
heavy metal accumulation in the soils is a
concern of matter because of its potential
health risks and detrimental effects on
soil ecosystems .
 The maximum concentrations of heavy
metals were recorded in both soil and
grasses in the traffic congested area and
areas where rapid industrialization and
urbanization take place.
 The higher concentration of Pb and Cr
in vegetables (Green arum leaves, jute
leaves, water spinach, bottle gourd, wax
gourd and sweet gourd collected from
industrial area (Nasirabad, Agrabad,
Vatiary and Chalkbazar).
Coastal Area
 Ship breaking area in Chittagong is
highly affected by heavy metal. The
sediment samples were moderately to
heavily polluted with Pb, Cu, Zn and Cr
but the concentrations in water were
found below the permissible limit.
 Bay of Bengal coast’s sediment was
highly polluted with heavy metals that
originated mainly from domestic and
industrial discharges, gas production
plant, agriculture and shrimp farming.
 Higher concentrations of Cd (.07) and Pb
(0.75) µg/g were recorded from Bay of
Bengal coast that exceeded the
Environmental Quality Standards of
Bangladesh (Cd: 0.05 and 0.10 µg/g).
 Millions of the trees and people in
Sundarbans are being affected by heavy
metal contamination.

19. Heavy Metal concentration of
Dhaka metropolitan city