organic input in aquatic system and their impact

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ORGANIC INPUT IN AQUATICSYSTEM & THEIR IMPACT

BY SUJIT KUMAR & UDAY KUMARFISHERIES COLLEGE& RESEARCH INSTITUTE, TUTICORIN,(TANUVAS)

Introduction:Organic input in the aquatic system & organic pollution is almost similar te

rm except that organic input may be internal ie. Indigenous but organic pollution will be always external, not caused by indigenous organism. Organic materialsare the compound that can readily decomposed by the microorganism. Organic matter in any water bodies are found in trimorphic condition i.e. three forms :-

DOM , POM & colloidal formDissolve organic matter (DOM) :-

Organic matter which can pass through 0.45 Âµm filter. It is how recognisedthat dissolve organic compounds may influence the state of inorganic substances

in the sea water & also affect sedimentary process in the water bodies. DOM canbe commonly measured as DOC in oceans.Particulate organic matter (POM) :-

Organic matter which canât pass through a 0.45Âµm filter. It is also calledas seston & is an important component of food chain in sea. POM includes both living 7 non-living suspended particles in the sea larger than 0.5Âµm diameter.Colloidal form :-

It is formed due to adsorption of the water by the organic matter. Size range is similar to DOM.All natural water bodies can oxidize organic matter without development of nuisance conditions provide that the organic matter load is within the range of oxygen resources of water. In balanced aquatic system the indigenously produced organic matter is always in amounts that allow its complete degradation by the oxygen

available in water, without disturbing its natural balance. It is only when thesystem receives organic matter in excess form outside, the oxygen tends to diminish & lead to the development of hypoxic or totally anaerobic conditions.

Both aerobic & anaerobic organisms are cosmopolitan. An increase in organic load (input) a system 1st activates the aerobic microorganisms which exhaust the O2 supply of water. When O2 supply of water is less than BOD it leads to theactivity of anaerobic microorganisms which leads to accumulation of nitrates, sulphates, amino acid etc. In aquatic system.

The overall decomposition of organic matter yield stabilised end productsincluding the plant nutrients leading to the eutrophication especially in region away from the mixing of organic wastes. All these organic inputs results intopollution of water bodies which has adverse effect on the system affecting both

biotic & abiotic factor of that ecosystem & results in destruction of that ecosystem.Nature of organic matter :-All the organic substances which can serve as food for living organism to obtaintheir energy needs and to build new cells can be termed as organic matter. Theorganic matter based on its origin can be divided into two main categories i.e.,synthesized naturally by biochemical means and synthesized chemically in the laboratory. However except for a few most synthetic compound are biologically inert to degradation and hence cannot be considered in the category of organic matter. The non biodegradable organic materials affect the ecosystem in a different way.

The most commonly found organic materials ,both in the nature and in organic wastes are the biologically originated carbohydrate , fat and proteins,which

are readily utilized by the microorganism as thelr energy source and even serveas foods for higher organisms.Carbohydrate:



Carbohydrate are the organic compounds containing C, H & O(CHO) in which the hydrogen & oxygen atoms are present in same ratio in which they occur in water(2Hydrogen:1Oxygen). A no. of industries which process wood, cotton, textile, paper &food have substantial quantities of carbohydrates in their waste water. The carbohydrates can be grouped in three main categories based on the structure1. Monosaccharides2. Disaccharides

3. Poly saccharidesMonosaccharides are the simplest sugar made up of either 5 Carbon chain(pento

ses) or of six carbon chain(Hexoses). The general formula of pentose is C5H10O5& hexoses is C6H12O6 .

Disaccharide composed of two molecule of hexose sugars with a general formulaof C12H22O11. Three main types of disaccharide sugars are sucrose, maltose andlactose.

Polysaccharides are condensation products of monosaccharide sugars. The important polysaccharides are starch cellulose & hemicelluloses. In starch(C6H10O5)xhundreds of glucose molecules are joined in definit fashion. Cellulose also have same general formula as starch, but the glucose units are joined differently.Hemicelluloses have alternate units of pentoses & hexoses.

Fat:- Fats also contain C,H,and O,but unlike carbohydrate ,the oxygen is present in much lesser quantity . they are sparingly soluble in water but get readilysoluble in organic solvent . chemically lipids are esters of glycerol .

The fatty acid present in the lipidare usually 16-18 carbon atoms , though acids with smaller carbon chains my also occur in appreciable quantities in certain fats . the lipid are called as oilwhen they are liquid at normal temperature & fats when they are solid. The oilhas predominance of unsaturated fatty acids, whereas fats usually have saturatedacids .Proteins

Proteins have C,H O&N with small quantity of S occasionally. Because of highnitrogen content of protein which varies from 15-18% they are commonly consider

ed as nitrogenous organic matters.Unit of protein is amino acids which are linked by polypeptide bonds . there

are 20 different types of amino acids which form building blocks of proteins different sequences.

An amino acids is amphoteric in nature having two active groups the amine(-NH )& acid (-cooH ). A few amino acids like cystine & methionine also containsulphure.Phosphorus containing compounds:-

A large number of organic compounds contains phosphorus in varying amount . following are the list of compound-Nucleotides(DNA&RNA) having units of purine & pyrimidine

Polyribose nucleic acid

ATPADPAPS(adenocine phospho sulphate)NAD

The phosphorous in the compounds is mainly present as phosphate radical (PO4-)

Other organic compoundsUrea in an important organic compound present in appereciable quantity in e

xcreta of animals & man . it is a nitrogen bearing compound . Source of organic matter (organic input)

Source of organic matter to the aquatic system can be classified primarilyinto two :-

External (allochthoonous)Internal(autochthonous)

a) External (allochthoonous)



External Source of organic matter can be grouped into two on their origin1)Anthropogenic (human interference)2)Natural

1) Anthropogenic (human interference)It includes the organic matter produced due to human interference. It can b

e further studied in following heading :-a) Municipal sewage & solid waste

b) Industrial waste waterc) Agriculture State wise waste water generation in India

a) Municipal sewage & solid waste :-It include mainly the sewage released from domestic areas. It includes orga

nic material such as excreta, detergent, food material & other household organicwastes. Average raw sewage contains usually 1.0 % solid which remain both in suspended & dissolved form. Of the organic constituent 65% are nitrogenous (mainlyprotein), 25% are carbohydrate & 10% are fat(Tebbut 1977). Discharge of sewagecan put great quantities of nitrogenous organic waste in the water bodies. Even

after the conventional secondary treatment a large quantity of dissolved organicmatter remains in sewage which may be still enough to cause organic pollution.Human waste :-

It includes the excreta of alimentary canal, termed as faces.they mainlyconsist of intestinal bacteria, which comprises the most bulky portion of humanwaste. The urine of which about 1.5 l get excreted daily by human adult, has been mostly water dissolved nitrogenous wastes & salts. The urine also carried awayforeign substances like drugs & other toxins.

Detergent :-Detergent have attracted special attention in many countries because of a vari

ety of pollution problems involving their constituents. Accourding to rigorousdefinition, a detergent may be defined as anything that behaves as a cleaning a

gent.The appearance of bubbles & foams on a glass of water drawn from kitchen ta

p was the 1st indication to many people that the domestic water in some are is not very pure. The froathy âheadâ on a glass of drinking water was caused by presence of surfactant. Detergents consist of surfactant or surface active agent & a number of builders. The surfactant lowers the surface tension of the liquid in which it is dissolved by concentrating at surfaces & interfaces & its cleaning properties arises from its ability to replace dirt on surfaces by being preferentially absorbed at surfaces & by helping the dirt to be carried away as stabllizedemulsion or suspension.

The surfactants generally consists of polar or hydrophilic groups (such asCO32-, SO32-, NH4+, PO43-) that are soluble in water & oily or lipophilic groups

that are soluble in lipids .some example of surfactants are as given below :-Alkyl benzene sulfonates (A.B.S.),Linear alkyl sulfonate (L.A.S.)AMMONIUM SALTS (cationic surfactant)Polyoxyethylene (non ionic )Phosphate is one of the major component of surfactant. Sodium tripolypho

sphate , the most widely used phosphate builder in detergent , is one of a family of phosphate used extensively in detergent.

POLYPHOSPHATE builders are of great concern because they and their hydrolysis products obviously contains phosphorous ,which has been implicated in theeutrophication process.it is generally accepted that detergent use account forabout 50% of the phosphate in the waste water ; near large metropolitan areaswhere there has been little dilution of waste waters,some estimates that 70% isdetergent

Solid wasteSolid waste contains little percentage of water . it includes unused foo

d materials ,paper ,waste of vegetables,fruits , & many other inorganic both deg



radable &non degradable materials such as plastic glass bottle etc. Dumping of solid waste in water bodies leads to the addition of organic waste to the water bodies .Industrial waste water

Industrial waste waters are important source of organic matter & is of different nature . a numbr of industries like food processing industries ,dairy paper & pulp, sugar distilleries breweries tanneries textile & other have cons

iderable quantities of organic matter of varying nature besides other pollutants. the volume of waste water from these industries is relatively large & causedorganic pollution after they are diverted to municipal sewers or are directly discharged in the aquatic systems without any treatment .Table :-characteristics of some important organic wastes released from differentindustries

Release of oil incidently or intentionally in the sea is also an important source of organic material .oil is a natural substances ,extracted usually from The upper strata of the earth,& commonly called as petroleum. Crude petroleum is a mixture of several complex hydrocarbon, including substances bearing nitrogen ,sul

phur,& oxygen. Hundreds of small or big cases of oil spill occur every year areas follows:-Torrey canyon oil tanker ship carrying 1,17,000 tons crude oil, ran aground at the western entrance of the english channel near Britain in march .the argentineship bahia paraiso wrecked near the antrtica shoresin January 1989 spreading the oil in several kilometre area. In one of the worst oil spills in the arabin sea affecting the Indian coast amaltese oil tanker puppy collided with a containervessel world quince about 550 kilometer away from bomby on june 28,1989 . it

spills nearly 5000 tons of oil into the ocean.Inspite of these incidents release of oil&grease occur fromthe fishing

vessels & other ship also aid some amount of organic matter to the sea.Huge amount of waste materials such as unused food material, excreta,

damaged net etc re directly released into the sea.

AgriculturalFor the better production different types of fertilizers are use

d which includes both organic & inorganic fertilizers. Pesticides are biologically active chemicals which are used for killing the pest . most of the chemicals used as pesticides are synthetic organic compounds .examples of pesticides are as below :-

RotenoidsNicotine alkaloidPyrethroidChlorinated hydrocarbon (DDT,DDD,BHC,aldrin )Organic phosphate chemical(malathion,parathion,TEPP,DDVP) A

long with surface runoff these pesticides and fertilizers carry to the water

Dynamics of pesticidesSurface run off :

The run-off originating from urban areas picks up large quantities of organic matter from the streets, houses, gardens and other places and reach bodies of water through municipal sewers or directly. The urban run-off is especiallyimportant at the onset of rainy season after the dry spell during which huge quantities of organic matter accumulate in the city drains.Rural run-off originates from the sparsely populated and from natural vegetatedareas. The run-off contains various quantities of organic matter derived mainlyfrom the dead plant matter from the annual and deciduous vegetation. The run-offpassing through the agricultural res my also pick up substantial quantities oforganic manure, and dried parts of the crop plants. The rural run-off, in genera

l, is of diffuse nature with no point sources.INTERNAL (autochthonous) â

Different indigenous activity such as volcanic eruption , dead decaying ani



mals ,excreta of animals etc adds organic matter in the water bodies. The organic matter produced indigenously within the water bodies is the results of primary& secondry production. The advanced stage of eutrophication often show the symptom of high organic load due to accumulation of excessive dead organic matter. The growing plant &animals also secrete a variety of trace organics in natural water. The algal and fungal growth produce several organic compounds which impartscharacteristics taste & smell to the water . some examples of these compounds ar

e as below :-Dimethyl sulphide,methyl mercaptum , butyl mercaptum etc .

Volcanic eruption adds heavy amount of organic material along with different elements.Degradation of organic compound-

There are three factors responsible for degradation1.physical2.chemical3.biological

Physical factor includes wind action, sunlight, waves, tides, etc. Chemical fact

or includes all the present ions in the water. Biological factors includes all the saprophytic & other microorganism. Among all these factors biological factorsare more responsible for degradation.

The degradation of organic matter in water is facilitated by different microorganisms that stabilized the organic matter by forming the end products usually immune to further degradation, such as CO2, H2O, NH3, H2S etc.

The degradation of organic matter is also called oxidation due to releaseof hydrogen and electron which are finally accepted by oxygen or in absence of it by some other acceptor to form water and other by-products.

The aerobic oxidation yields the end products which are usually simple andstable, but the anaerobic oxidation is always associated with accumulation of some relatively simpler but unstable compound like alcohols, ketones, acids, methane and others.

Hydrolysis is the important biochemical reaction carried out by extracellular enzyme whereupon the water is added to break down larger molecules, such as of polysaccharide, protein & fat into monosaccharide, amino acids and organicacid respectively.Degradation of carbon compounds:-

The lower molecular weight carbon compounds inside the microbial cells are degraded by intracellular enzymes. In aerobic conditions, the overall reactionis accomplished by a series of enzyme reaction that dehydrogenate each moleculesequentially and hand over the liberated hydrogen to oxygen forming water.

C6H12O6 + 6O2 â 6CO2 +6H2OAn aerobic degradation can be summarised by the following rection.

C6H12O6 â

2CO2 + 2C2H5OHDegradation of nitrogen containing compounds:-The most abundant biologically important nitrogenous compounds formed

after hydrolysis of heavier molecules are amino acids,nitrogen bases (purines &pyrimidines) and urea.Anaerobic degradation Aerobic degradation The urea is degraded into carbondioxide and ammonia by the reaction of hydrolysis which is carried out by a no. of organisms. Reaction is given below:

Dynamics of nitrogen containing compoud



Degradation of sulphur containing compound:-It can be shown by following chart

Production of hydrogen sulphide

Degradation of phosphorus containing compound:-

All phosphorus containing compounds yield inorganic phosphate after decomposition as shown in the following reaction Parameters for measuring organic pollution:-

Three parameters1) Physical2) Chemical3) Biological1)physical parameters- temperature & colourTemperature:- since the BOD is based on biological activity, temp. Greatly influences the rate of oxygen consumption. To estimate the temperature effects, it has been agreed upon to measure the BOD universally at 200C.

Colour:- aquatic bodies having high organic load black in appearance.2)chemical parameter- BOD, COD, SOD & TODBOD:- All oxidizable organic matter when degraded by aerobic microorganisms consumes the oxygen present in water. The respiratory demand for oxygen exerted by microorganisms, while stabilizing the organic matter under aerobic conditions, iscalled âbiochemical oxygen demandâ(BOD). On an verage basis, the oxygen consumed bythe microorganisms is proportional to the magnitude of organic matter present in water. The amount of BOD can be determined by using following equation: BOD levels at different dilution of organic material can be measured from following table. COD:- Chemical oxygen demand is a rapid test carried out for determination of t

he total oxygen demand by organic material present in the sample. In this test organic matter is oxidized by making use of a strong chemical oxidizing agent unlike BOD where oxidation is carried out by microorganism. The COD test, though not a satisfactory substitute of BOD because of some limitation , still consideredto be the best method for organic matter estimation mainly because of its rapidity in performing the test.

The COD value do not indicate whether the organic matter present in the sample is biodegradable & rate of oxygen consumption bythe system. At the same time there may be many organic materials that are chemically oxidizable but not by biological means & vice-versa for example , organic materials like aromatic hydrocarbon , pyridine, benzene,tolune &nitrogen in the form of ammonia are not chemically oxidizable but get readily oxidized by microor

ganism.SOD:- sediment oxygen demand is the amount of oxygen required for oxidation by the sediments. Higher the organic load of sediment higher will be the SOD.TOD:- total oxygen demand refers to the total amount of oxygen required to burnthe whole sample .Other chemical parameter:-

The values of organic carbon, ammonical nitrogen , total organic phosphorus,&even oxygen can also be interpreted in terms of organic pollution, & can be taken as a measure of organic pollution.3)biological parameter:- it includes smell& microorganism.

Smell-aquatic body having high organic load have a pungent smell due excessive release of ammonia &hydrogensulphide due to degradation mechanism of microorganism.

Microorganism: there are certain type of microorganism which are indicator of certain type of organic matter as given below

E.coli-Municipal waste(more faecal matter)



Water hyacinth-phosphate input.Algae âhigh nutrient load

There are different types of biological indices of organic pollution likeShannon & weiner diveraity indicesOdums indexKothes species deficit indexGoodnight & whitley s index

Palmur s algal genus indexEutrophication , a result of high organic input : -

The process of increase in the nutrients of waters & as a result of spurt in algal productivity is called eutrophication . the present concern for eutrophication relates to the rapidly increasing quantity of nitrogen & phosphorous with organic matter & other sources. The process of eutrophication is greatlyinfluenced by the increased supply of nutrients through various human activitiessuch as discharge of domestic sewage , industrial waste , agricultural and urban run off.this increased supply of nutrients triggers the algal growth at a muchfaster rate , thus increases the speed of eutrophication . the relation of therate of eutrophication with the age of water bodies is as shown below:-

Eutrophication has adverse effect on animal of that water bodies because itreduces the available O2 & other nutrients which leads to the mass mortility ofaquatic animal.Conclusion

Although addition of organic matter to the water bodies is a part of biochemical cycle but if addition crosses its threshold it affects the ecosystem of that water bodies very badly & ultimately leads to the destruction of biodiversity of that ecosystem.Reference

Goel .P.K(1996).water pollution causes, effect and control.new age interna

tional publishers, 39-43,61-86, 88-94Mohapatra B.C. Saha C.(2000). Aquatic pollution & Management. C.I.F.A.(I.C.A.R.)Bhubaneswar. 29-34, 65 ,Chhatwal G.R. Ktyal T. Mohan Katyal, Mehra M.C.,Satake N. , Nagahiro T. , Enviaomental water pollution and its control , Anmol publication , New Delhi . 200-203,

organic input in aquatic system and their impact

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