Aquatic pollution

1. BRIJESH CHAHAR
PhD Scholar
b0001chahar@gmail.com
CCS Haryana Agricultural University, Hisar
AEM 302 Course
Aquatic Pollution
Agricultural wastes- organic detritus,nutrients, Adverse effect of oxygen demanding
wastes, importance of dissolved oxygen,BOD,COD,Excessive plant
nutrients,Eutrophication,Red tides, Algal blooms

2. Agricultural wastes
• Agricultural waste is defined as unwanted waste produced as a result
of agricultural activities (i.e., manure, oil, silage plastics, fertilizer,
pesticides and herbicides; wastes from farms, poultry houses
and slaughterhouses; veterinary medicines, or horticultural plastics).
• Agricultural wastes from agro-based industries, such as palm oil,
rubber, and wood processing factories have increased by more than
threefold.
• Common agricultural wastes include:
-Packaging and processing of agro products, Silage plastics,
Redundant machinery, Tyres, Netwrap, Oils, Batteries, Old fencing,
Scrap metal, Building waste.
• Other less common wastes include unused pesticides and veterinary
medicines, horticultural plastics.

3. Nutrient content in agricultural wastes
• In addition to meat, livestock and poultry operations produce another
valuable commodity—manure. Manure is a by-product containing
many plant nutrients and organic matter.
• Manure provides valuable macro- and micronutrients to the soil. It
also supplies organic matter to improve the soil’s physical and
chemical properties.
• Manure also increases infiltration of water and enhances retention of
nutrients, reduces wind and water erosion, and promotes growth of
beneficial organisms. It can also be used as a fertiliser.
• The actual nutrient value of manure from a particular operation will
differ considerably with the method of collection, storage facilities,
and the species of animal.
• Factors Affecting Nutrient Composition of Manure
a)Nutrients in waste may be lost or converted to other forms during
treatment or storage and handling, affecting their availability for use by
growing plants..

4. b) Bedding and water have a diluting effect on the final nutrient
concentration of waste and result in less nutrient value per unit quantity.
c) In addition, the type of housing and waste handling system can
decrease the final nutrient composition of waste materials. For instance,
there can be considerable loss of nitrogen to the air, and there is a
potential for runoff and leeching when animal waste is exposed to
weather conditions in an open lot system. In contrast, there is
considerably less nitrogen loss from a completely covered feedlot with
manure pack or a liquid lagoon.
Factors Affecting Nutrient Composition of Manure

5. • Plant nutrients in commercial fertilizers are mostly water soluble and
readily available for plant uptake.
• Not all the nutrients in manure are available to crops during the year
of application because some are in their organic form, while others
can be lost during application. Therefore, an availability factor
(percent of nutrients available) is used for rate calculations based on
the quantities of nutrients available during the first year.
• The availability of nitrogen can vary from 30 to 80 percent depending
on the type of manure and application method. Most of the nitrogen in
lagoon effluent is in the ammonium form and is more subject to
volatilization loss during storage and land application.
• The greatest response from animal manure application can be obtained
by promptly incorporating the waste into the soil either by injection or
cultivation. The practice of injecting, chiseling, or knifing liquid
animal waste beneath the soil surface minimizes loss of nitrogen to air
or runoff. Therefore, use a lower availability factor if manure is
Nutrients in Manure and Commercial Fertilizers

6. • The time of manure application also affects the quantity of nutrient
available to a crop. Higher availability is expected when manure
application matches the crop nutrient uptake.
• The availability of phosphorus and potassium in manure is considered
similar to that in commercial fertilizer since the majority of
phosphorus and potassium in manure is in the inorganic form. For all
manure types, 90% of phosphorus and potassium is considered to be
available during the first year of application and 10% for future years.

7. • Measures of dissolved oxygen (DO) refer to the amount of oxygen
contained in water, and define the living conditions for oxygen-
requiring (aerobic) aquatic organisms. Oxygen has limited solubility
in water, usually ranging from 6 to 14 mg/l.
• DO concentrations reflect an equilibrium between oxygen-producing
processes (e.g. photosynthesis) and oxygen-consuming processes (e.g.
aerobic respiration, nitrification, chemical oxidation), and the rates at
which DO is added to and removed from the system by atmospheric
exchange (aeration and degassing) and hydrodynamic processes (e.g.
accrual/addition from rivers and tides vs. export to ocean) .
 What causes dissolved oxygen concentrations to change?
• Solubility of oxygen varies inversely with salinity, water temperature
and atmospheric and hydrostatic pressure.
• Dissolved oxygen consumption and production are influenced by
plant and algal biomass, light intensity and water temperature
(because they influence photosynthesis), and are subject to diurnal and
What is dissolved oxygen

8. • DO concentrations naturally vary over a twenty-four hour period due
to tidal exchange, and because there is net production of oxygen by
plants and algae during the daytime when photosynthesis occurs. By
comparison, plants and algae only respire at night time, and this
process consumes oxygen. Highly productive systems are expected to
have large diurnal DO ranges.
• Nutrient enrichment stimulates plant and algal growth (and algal
blooms) and often results in a mass influx of particulate organic
matter to the sediments (eutrophication). The decomposition of this
labile organic matter by aerobic microorganisms leads to a rapid
acceleration of oxygen consumption, and potential depletion of
oxygen in bottom waters.
• Stratification can isolate bottom waters from oxygen enriching
processes and can give rise to anoxic and hypoxic events. This
problem is most acute in wave-dominated coastal systems (e.g. deltas,
estuaries and strandplains and lagoons) because these systems

9. • Coastal discharges of wastes rich in organic carbon (e.g. from sewage
treatment plants, paper manufacturing, food processing and other
industries) are produced in large quantities in urban population
centres, and can substantially reduce dissolved oxygen concentrations.
• The oxidation of pyrite found in acid sulfate soils can rapidly strip
oxygen from the water, and gives rise to acid drainage. Acid drainage
may result from natural processes but in many cases the draining of
coastal wetlands (e.g. mangroves and salt marshes) is the cause.

10.  Significance of dissolved oxygen
• Most aquatic organisms require oxygen in specified concentration
ranges for respiration and efficient metabolism, and DO concentration
changes above or below this range can have adverse physiological
effects. Even short-lived anoxic & hypoxic events can cause major
"kills" of aquatic organisms.
• Exposure to low oxygen concentrations can have an immune
suppression effect on fish which can elevate their susceptibility to
diseases for several years. Moreover, the toxicity of many toxicants
(lead, zinc, copper, cyanide, ammonia, hydrogen sulphide and
pentachlorophenol) can double when DO is reduced from 10 to 5
mg/l.
• The death of immobile organisms and avoidance of low-oxygen
conditions by mobile organisms can also cause changes in the
structure and diversity of aquatic communities.

11. • In addition, if dissolved oxygen becomes depleted in bottom waters
(or sediment), nitrification, and therefore denitrification, may be
terminated, and bioavailable orthophosphate and ammonium may be
released from the sediment to the water column.
• These recycled nutrients can give rise to or reinforce algal blooms.
Ammonia and hydrogen sulphide gas, also the result of anaerobic
respiration, can be toxic to benthic organisms and fish assemblages in
high concentrations.

12. • What is Biological oxygen demand and how does it affect water
quality?
• Biochemical oxygen demand (BOD) is a measure of the quantity of
oxygen used by microorganisms (e.g., aerobic bacteria) in the
oxidation of organic matter. Natural sources of organic matter include
plant decay and leaf fall.
• However, plant growth and decay may be unnaturally accelerated
when nutrients and sunlight are overly abundant due to human
influence. Urban runoff carries pet wastes from streets, nutrients from
lawn fertilizers; leaves, grass clippings, and paper from residential
areas, which increase oxygen demand.
• Oxygen consumed in the decomposition process robs other aquatic
organisms of the oxygen they need to live. Organisms that are more
tolerant of lower dissolved oxygen levels may replace a diversity of
natural water systems contain bacteria, which need oxygen (aerobic)
to survive. Most of them feed on dead algae and other dead organisms
Biological oxygen demand

13. • Chemical oxygen demand (COD) is a measure of the capacity of
water to consume oxygen during the decomposition of organic matter
and the oxidation of inorganic chemicals such as ammonia and nitrite.
COD measurements are commonly made on samples of waste waters
or of natural waters contaminated by domestic or industrial wastes.
• COD is measured as a standardized laboratory assay in which a closed
water sample is incubated with a strong chemical oxidant under
specific conditions of temperature and for a particular period of time.
• A commonly used oxidant in COD assays is potassium dichromate
(K2Cr2O7) which is used in combination with boiling sulfuric acid
(H2SO4). Because this chemical oxidant is not specific to oxygen-
consuming chemicals that are organic or inorganic, both of these
sources of oxygen demand are measured in a COD assay.
Chemical Oxygen Demand

14. • COD is related to biochemical oxygen demand (BOD), the standard
test for assaying the oxygen-demanding strength of waste waters.
However, BOD only measures the amount of oxygen consumed by
microbial oxidation and is most relevant to waters rich in organic
matter.
• It is important to understand that COD and BOD do not necessarily
measure the same types of oxygen consumption. For example, COD
does not measure the oxygen-consuming potential associated with
certain dissolved organic compounds such as acetate. However,
acetate can be metabolized by microorganisms and would therefore be
detected in an assay of BOD. In contrast, the oxygen-consuming
potential of cellulose is not measured during a short-term BOD assay,
but it is measured during a COD test.

15. • Organic matter affects both the chemical and physical properties of
the soil and its overall health. Properties influenced by organic matter
include: soil structure; moisture holding capacity; diversity and
activity of soil organisms, both those that are beneficial and harmful to
crop production; and nutrient availability.
• It also influences the effects of chemical amendments, fertilizers,
pesticides and herbicides.
• Soil organic matter consists of a continuum of components ranging
from labile compounds that mineralize rapidly during the first stage of
decomposition to more recalcitrant residues (difficult to degrade) that
accumulate as they are deposited during the advanced stages of
decomposition as microbial by-products.
• Effect of organic matter on biological properties of soil
Soil microorganisms are of great importance for plant nutrition as they
interact directly in the bio-geo-chemical cycles of the nutrients.
Effects of organic matter on soil properties

16. • Chemical properties
• Many important chemical properties of soil organic matter result from
the weak acid nature of humus. The ability of organic matter to retain
cations for plant use while protecting them from leaching, i.e. the
cation exchange capacity (CEC) of the organic matter, is due to the
negative charges created as hydrogen is removed from weak acids
during neutralization.
• Many acid forming reactions occur continually in soils. Some of these
acids are produced as a result of organic matter decomposition by
microorganisms, secretion by roots, or oxidation of inorganic
substances.
• Commonly used nitrogenous fertilizers work through the microbial
conversion of NH4
+ to NO3
-. In particular, ammonium fertilizers, such
as urea, and ammonium phosphates, such as monoammonium and
diammonium phosphate, are converted rapidly into nitrate through a
nitrification process, releasing acids in the process and thus increasing

17. Physical properties
• Organic matter influences the physical conditions of soil in several
ways. Plant residues that cover the soil surface protect the soil from
sealing and crusting by raindrop impact, thereby enhancing rainwater
infiltration and reducing runoff. Increased organic matter also
contributes indirectly to soil porosity (via increased soil faunal
activity).
• Fresh organic matter stimulates the activity of macrofauna such as
earthworms, which create burrows lined with the glue-like secretion
from their bodies and intermittently filled with worm cast material..
• Organic matter also contributes to the stability of soil aggregates and
pores through the bonding or adhesion properties of organic materials,
such as bacterial waste products, organic gels, fungal hyphae and
worm secretions and casts. Moreover, organic matter intimately mixed
with mineral soil materials has a considerable influence in increasing
the moisture holding capacity.

18. • Aquatic plants and algae gradually fill in freshwater lakes and
estuaries over time in a natural process called eutrophication. This
process is controlled by low concentrations of certain nutrients (like
phosphate and nitrogen) that the plants and algae require to grow.
Usually, phosphorus is the limiting nutrient in freshwater and nitrogen
in estuaries and salt water.
• However, when humans release nutrients like phosphate (agriculture
~50%, human metabolism ~20%, industry ~10%, detergents ~10%
and natural erosion ~10%), the process of eutrophication is
accelerated.
• In a worst-case scenario, the excess growth of plants and algae can
smother other organisms when they die and begin to decay. An
eutrophication indictor is derived by converting the different chemical
forms of phosphorus and nitrogen into a common or equivalent form.
Then, the proportion normally found in aquatic algae is used to weigh
the phosphorus and nitrogen. These values are added into an overall
Eutrophication

19.  The major and minor plant nutrients in aquatic systems
• For terrestrial gardeners, a listing of the major or macro- nutrients of
aquarium-useful plants include nitrogen, phosphorus and potassium
and more.
• Additional major or macro-nutrients and minor/micro-nutrients follow
the same general rule; and as with land plants organic and inorganic
nutrients are provided by mineral and biological sources.
• Aquarium plant life is favored over the air outside, physical support,
moderation of the ill effects of varying water availability ,etc. But this
surfeit of water is a "double edged sword", aquatic factors often affect
the usefulness and uptake of necessary chemical species.

20.  Element form of Concentration Some Functions Absorption as a
% of dry wt.
•Nitrogen NO3
- ( NH4
+) 1-3% Amino acids, proteins, nucleic acids,
chlorophyll, coenzymes
•Phosphorus (H2PO4) 0.05-1.0% High energy molecules ATP, HPO4
2-
ADP, nucleic acids, phosphorylation of sugars, essential coenzymes,
phospholipids.
•Potassium( K+) 0.3-6% Enzymes, amino acids, protein synthesis,
enzyme activator, stomata opening/closing
•Calcium (Ca+) 0.1-3.5% Cell wall formation, enzyme cofactor, cell
permeability.
•Magnesium (Mg2+) 0.05-0.7% Part of chlorophyll, enzyme activator.
•Sulfur (SO4
2-) 0.05-1.5% Some amino acids, Coenzyme A.
•Iron (Fe2+, Fe3+) 10-1500 Chlorophyll synthesis, ferredoxins,
cytochromes

21. Nitrogen
• Nitrogen is provided readily by decomposing organic matter, from soil
and/or fish food. It is used in large quantities by aquarium plants (and
microscopic aquatic life. Commercial aquarium plant fertilizers
contain nil to a few percent nitrogen.
• Nitrogen comes in several formats (nitrates, ammonia, ammonium)
and the formation and form of nitrogen compounds is influenced by
bacterial action, pH, temperature and more. Nitrogen is rarely a/the
rate-limiting factor in aquarium plant culture, and that a stable, system
will produce sufficient nitrogen for your plants use.
• Under varying conditions, your plants are able to utilize nitrogen from
several fixed sources; high nitrates, and/ or detectable levels of
ammonia are not necessary or desirable.

22. Phosphorus and Potassium
• Phosphorus and potassium also occur in more/less usable 'forms'; like
nitrogen, they rarely have to be augmented in a 'normal' set-up.
Enough comes into a system by way of tap and fish food sources to
supply all but the most "boosted" plant arrangements.
• In highly acidic conditions phosphate "fixing" can be a problem with
this material becoming insoluble, hence the use of some carbonaceous
material as substrate. Too much phosphorus as phosphate (less than
1ppm) results in algal blooms.
• Potassium shortage shows up in older leaves as small spots and holes,
resulting in leaf loss.

23. Calcium, Magnesium and Sulphur
• Calcium, magnesium and sulphur are generally not limited as major
nutrients either; sufficient concentration are derived from tap and food
sources. In soft water, calcium and magnesium may need
supplementation, which is best achieved through the substrate.
• Calcium is necessary for plant growth, as is sulphur , magnesium is
the central atom in every chlorophyll molecule. The lack of calcium
shows in dwarfed, gnarled growth and blackened, stubby roots.
Missing magnesium may result in yellow to white, transparent leaves.
Iron
Iron crosses over the border as a macro/micro-nutrient. Ferrous matter
is necessary in only small concentration, but is often a nutrient
deficiency cause of 'yellowing'. Your tap water may well not contain
enough iron material to meet your plants needs or be too alkaline,
precipitating it out of solution.
A sound approach to iron supplementation is inclusion in soil

24. Carbon
• Carbon, should we mention this, the most abundant plant element in
dry weight. Except in plant crowded and otherwise boosted (lighting,
chemical supplemented) systems, enough carbon as CO2 enters into
aquarium systems through respiration processes and the atmosphere.
Carbon can be 'forced' to become the rate limiting "minimum nutrient"
factor, as can iron under intensive culture, or calcium or magnesium in
soft water conditions.
• Carbon dioxide infusion is useful in other ways; principally as a
bicarbonate balancer in hard waters. The pH stabilization offered by
carbon dioxide infusion goes a long way to promoting luxuriant plant
growth.
Hydrogen and Oxygen
• Hydrogen and oxygen are the remaining macro nutrients of aquarium
plants. They are obviously not in short supply.

25. The Minor Mineral Nutrients
• Chlorine Cl- 100-10,000 Osmosis and ionic balance
• Copper Cu2+ 2-75 Activator of some enzymes
• Manganese Mn2+ 5-1500 Activator of some enzymes
• Zinc Zn2+ 3-150 Activator of many enzymes
• Molybdenum MoO4
2- 0.1--5.0 Nitrogen metabolism
• Boron BO3
- or B4O7
2- Calcium utilization, nucleic acid synthesis,
membrane integrity.

26. Minor Nutrient Availability and Consequences
• All these elements are absolutely necessary to plant life, and readily
supplied from tap, soil, and fish-food sources. Excepting specially
filtered tap sources, non-soil amended set ups, systems without fishes
and feeding, the minor or micro nutrients of aquarium plants are rarely
found in limited supply, unless these are driven to being deficient by
expediting growth and making the macro-nutrients alone available
through supplementation.
• Boron deficiency results in the stilted growth appearances of calcium
deficiency.

27. What is red tide?
• Red tide is a naturally-occurring, higher than-normal concentration of
the microscopic algae Karenia brevis (formerly Gymnodinium breve).
This organism produces a toxin that affects the central nervous system
of fish so that they are paralyzed and cannot breathe.
• As a result, red tide blooms often result in dead fish washing up on the
beaches. When red tide algae reproduce in dense concentrations or
"blooms," they are visible as discolored patches of ocean water, often
reddish in colour.
• What causes red tide?
• Red tide is a natural phenomenon not caused by human beings. When
temperature, salinity, and nutrients reach certain levels, a massive
increase in Karenia brevis occurs. No one knows the exact
combination of factors that causes red tide, but some experts believe
high temperatures combined with a lack of wind and rainfall are
usually at the root of red tide blooms. There are no known ways that
Red tide

28. Effect of Red tide
• The eye and throat irritation caused by red tide results from high
concentrations of the algae and rough surf. These conditions cause the
red tide's irritant to become suspended in the air in the salt spray.
There is typically little or no irritation when surf conditions are
relatively calm. In most red tides , these conditions vary a lot within
the space of days or even hours. As a result, the same part of the beach
may have irritating conditions in the morning and those conditions
may be gone by afternoon.
• On a calm day, even with red tide in the surf zone, many people can
enjoy the beach because there is not a lot of salt spray from the surf
carrying irritant to the beach. The best advice for beach visitors is if
they feel effects in an area, leave that area and try another one. Some
local authorities will post signs on beaches that they manage. Be
aware of all beach warnings when visiting the beach.
• How, when and where do red tide blooms start?
Texas red tides have occurred from August through February. They typically begin

29. Is it safe to eat oysters during a red tide?
Oysters and other shellfish such as clams, mussels, whelks and scallops
can accumulate red tide toxins in their tissues. People that eat oysters or
other shellfish containing red tide toxins may become seriously ill with
neurotoxic shellfish poisoning (NSP).There are, however, other risks
associated with bacteria and other contaminants in raw oysters.
Algal blooms in Indian waters
• The red tide is not an unknown phenomenon in Indian waters. Until
1973, sporadic blooms of Noctiluca scintilans, Trichodesmium
erythraeum, Rhizosolenia sp., etc. have been reported, but none were
of HAB type. However, since 1981, cases of paralytic shellfish
poisoning (PSP) from coastal Tamil Nadu, Karnataka and Maharashtra
were reported with adverse effects. In 1981, PSP resulted in the
hospitalization of 85 people and death of three persons due to the
consumption of bloom-affected mussel Meretrix casta in Tamil Nadu.

30. • A similar incidence took place in Mangalore in 1983, but in both the
cases causative species were not identified. In 1996, Gymnodinium
catenatum, a potent PSP species both as planktonic cells and cysts in
sediment, in the coastal waters of Karnataka (off Mangalore) was
reported. but the low number of cells had no toxic effect. In
September 1997, an outbreak of PSP was reported in three villages of
Kerala, resulting in the death of seven persons and hospitalization of
over 500, following consumption of mussel, Perna indica.
• During a reconnaissance cruise in 2001, on the coastal vessel Sagar
Shukti, a toxic algal bloom by hitherto unreported dinoflagellate
Cochlodinium polykrikoides was reported by the NIO team. Though
this species is a fish-killer in Korea, the cause for fish mortality
noticed off Goa could not be confirmed. These few examples
underline the unpredictable nature of the bloom and perhaps answer
the query regarding whether India should really worry about the
blooms.

31. Algal bloom Research in India
 Despite the fact that India has a fairly good spread of institutions
dealing with marine research, technology and teaching, interest in
bloom research could translate into about 300 scientific papers over a
period of 48 years. Some of the publications were due to instant
response to the bloom episodes, but research interest did not persist
further. The obvious reasons for this are:
• Indian waters were never seen as potential sites for recurring blooms
of temperate type and hence investigations were restricted to fulfill
academic pursuits.
• Trichodesmium and Noctiluca species were most dominant members
of the blooms reported. The blooms of these non-toxic species
therefore were not a cause for worry.
• The concept of blooms either in terms of their real extent or
composition for a discernible consequence remained obscure.
Algal bloom Research in India

32. • The blooms that discoloured the waters or the occurrence of even
‘miniblooms’ as a response to nutrient pulses, normally to be ignored,
were speculated to be harmful. Some even raised warning flags based
on substantial fish mortality or fall in their catch without actually
collecting scientific data. Among the 300 or so abstracts available,
only 80 (20%) dealt with bloom aspects and only a handful on
extensive blooms as perceived now
• A lack of clear distinction on the kind of blooms was obvious, as
descriptors such as ‘toxic’, ‘noxious’ and ‘nuisance’ have been
synonymously used, at times misplacing their real potency and vice
versa.
• Universities and research institutions have limited sea observation and
laboratory facilities, and therefore explorations and studies were
sporadic.
Algal bloom Research in India

33. SYMBOL OF TRUST