AQUATIC POLLUTION

V. Kunjukrishna Pillai and P. G. Jacob Central Marine Fisheries Research Institute. Cochin - 11

What is pollution? of the world. It is true that nature does its own adjustments by purifying the Today the world is faced with an Envir onments to maintain an ecological unprecedented menace o f growing balance. But , certainly there is a limit pollution" of its air, la nd and water. upto which this purification process can These three have been termed as the go. When the quantity of impurities world's major environments. The exceeds a limit, pollution is the out­ technological advances of the nations come. That is exactly what is happen- have been largely achieved as a result mg around us. . of great strides which the industry has made. Pollution of the environments When seen from the black depths thus seems a prize which mankind is of space, the earth appears to be a love­ paying for achieving affluence. , ly blue and white object with three­ which is on the threshold of industrializ­ fourths of its surface covered with water. ation, must make a serious note of the Next to air, water is the most important dlngerous consequences associated substance for all living objects on earth. with pollution and take lessons from The total quantity of water on earth has those countries which are faced with a been estimated to be about 1574 million formidable task of pollution control. cubic kilometers. The magnitude of The awareness towards pollution this figure will become clearer when is so alarming that International agencies one b e gins to realize that 1 cubic kilo­ like the FAO have already started a meter contains 34047 million litres of number of programmes for fighting en­ water. Of this, 97% is sea water, 2% is vironmental pollution. The environment frozen water in glaciers and ice caps :in which we live, the air we breathe, and the remaining 1% is what is .the water we drink and the food we eat, available on land. The term 'marine is polluted everywhere, varying only in pollution' is defined as "introduction by degree and intensity in different parts man of substances into the marine en­ vironment resulting in such deleterious -. The word pollution comes from the latin root effects as harm to living resources, . Lutum ' meaning . mud' and ' silt', hazards to human health, hindrance to

May, 1972 19 marine achvltle s including fishing , im­ le ad 'and many other mate rials are p airme nt of quality fo r use of sea water periodically d ischa rged into th e water, a nd reduction of amenities" (FAO. Fish. m ainly fr om factories . Se a water, Rep. No. 99. Conf. on p ollution, Ro me, ho wever, has a c()llsiderable buff ering Dec. 1970) . In general this definition capacity ; it can a bsorb relatively large c overs all aqua tic pollution. amounts of acids and alkalis which undergo little change in pH. Inorganic Causes and effects e ffl uents therefore, within limits, have only a localized effect. Fish and sm~ll Strong acids, other che micals and crustaceans are able to detect con­ to)(ic mineral wastes, pollute the once centrations of acids dnd alkalis much pristine rivers and s treams. Agri­ below the lethal (toxic) limit and will cultural pesticides poison and kill thus avoid these concentrations. The millions of fish and other forms of toxic action of both acids and alkalis is aquatic life. The r ole of the oceans and largely associated with the effect that seas as vital links in the life-giving cycle they produce on the transfer of oxygen on the earth may one day end if they and carbon dioxide across the g ill continue to be polluted at the present surface. At higher concentrations these rate. s ubstances corrode the gills which eventually will prove to be lethal. Domestic se wage lar gely includes dissolved organic and suspended con­ Phosphate enters the sea via rivers stituents. These give it a high 1;>io­ and from the sewage. Nitrate is in­ chemical oxygen demand (BOD*) and a high concentration of nutrients troduced into the sea from rainfall and (phosphorus and nitrogen compounds land runoff. Am onia is made available etc.). This type of pollution, to a certain to the marine environment either degree, gives rise to enrichment of through nitrogen fixation in the sea or water or eutrophication. *. by denitrification. Both these nutrients (nitrates and phosphates) are essential Pesticides like DDT, Dialdrin, Mala­ for increasing the productivity of the thion and Parathion are h armful to marine environment. But over-abund­ aquatic animals. Crustaceans are parti­ ance of these can le.d to situations CUlarly sensitive to these chemicals, when blooms of phytopla nkto n appear which in concentrations as low as and these are generally followed by 0 .003 ppm have often been found to be deoxygenation and anae orobic con­ lethal to shrimps. Fish have been found ditions. to tolerate even higher concentrations of these chemicals for short periods. The major sources of pollution by industrial wastes are the effluents from [norganic wastes such as acids, alkalis, ammonia, phosphorus, mercury, chemical factories and refineries. [n many cases these are discharg ed direct­

*800 - number of parts of OXyg~D absorbed by ly into the rivers, estuaries and the se~. 10,00,000 parts of water in five days. A variety of organic compounds thrown U Eutrophication - The term (e utrophication) refers as wastes become toxic to marine or­ to natural or artificial add ilions of nutrients ganisms. [n pulp mill wastes there are to bodies of water and to the effects of added nutrients. usually sulphur-containing compounds,

20 Seafood Export Journa L arising from the wood digestion process solubility of oxygen in water and thus and chlorinated phenolic compounds as increases the metabolic activities of a result of bleaching of the pulp. A microflora and fauna . This in turn may high BOD is characteristic of untreated lead to high BOD and eutrophication. sulphite pulp effluents, and organic Special care is therefore needed in wastes. Many instances of fish mortality e recting power stations which employ have been reported because of the water for cooling, particularly in tropical depletion of oxygen in waters receiving areas where animals and plants have effluents with a high BOD load. The a rather narrow range of temperature effects of industrial organic wastes are tolerance. often of a long-term nature. These inter­ fere at various trophic levels of the food Aquatic poliution in India chain, and ultimately lead to a gradual depletion of the coastal marine re­ Our country has a coast line of more sources, than 5000 km with a number of rivers and estuaries that periodically enrich Oil and oil-products enter the marine the coastal waters with essential nutri­ environment from shipping operations, ents and minerals. The rivers, estuaries both on the high seas and at ports, and and backwaters serve as nursery also by the discharge of oil products grounds for many of our fishes and into the rivers, se wers and finally to the prawns. Lately, there have been com­ sea (upto 5 milliotl tonnes per annum). plaints that our rivers, backwaters, In general, oil is lighter than water and est~ries and bays are getting polluted, spreads fairly rapidly, forming a thin resulting in considerable decline of film, which moves over the surface by fishery in these waters. It may be true wind, waves and tides. The accident that pollution of our waters is not so which occurred to the giant oil-tanker, serious as in the industrially advanced Torrey Canyon, polluted vast stretches countries, but a complacent attitude of water and beaches with crude oil. should not be taken before the problem Such extensive films of oil affect the becomes too far advanced. The rapid floating plankton and also the marine urbanization and industrialization with­ life along the beach. Much of the earth's out proper planning are the main causes .supply of oxygen is produced by the of pollution in our waters. Most of our -phytoplankton of the sea, which are factories do not have proper waste easily killed by the floating oil. treatment plants to control pollution. Most of our cities also lack sewage Thermal pollution or warm water treatment plants. -discharge from industries and power plants also has a deleterious effect on Almost every river in India is to the aquatic life. The worst offenders some extent contaminated or polluted. seem to be the atomic reactors, fertilizer It can adversely affect the use of water and rayon factories . Besides killing the for our domestic ne eds, industrial use, fish and smaller aquatic animals, the pisciculture and recreational activities. solubility of the salts present in water Cholera, typhoid and dysentery have increases and when evaporation takes long been known to be associated with place, the concentration of dissolved polluted water. Org'anic matter con­ salts increases. It also dereases the sumes oxygen of water, kills the fish

May, 1972 21 and produces offensive smells. Exces­ harbour has become practically -devoid sive fertilizers in the water act as of any fish life. The scientists from the nutrients for weeds and algae in the Sub-station of CMFR1, Calicut, h ave re­ rivers and estuaries which may then ported fish mortality from this area due grow to alarming proportions. One of to pollution as early as 1968. Now the the best examples of this is the African situation is so serious that the paddy weed (Salvinia spp.) which has become cultivators of the area are agitating a menace in the backwaters of . against the factory management because eV3n the paddy fie Ids are affected by The river Ganga is a sacred river the polluted river. Pollution of the and for various reasons its water is con­ river because of the adjacent sidered pure and holy. But the havoc industrial belt near Al waye is becoming done to Ganga at Monghyr by the wastes more and more widely known. Tonnes from Barouni Oil Refinery is still fresh in of hydrochloric acid. phosphoric acid, our minds. What is true of Ganga is hot water and other effluents are p oured true of most of the other rivers in India. into the river every day. All these flow The conditions of Coo urn and Adayar into the backwaters enroute the Arabian rivers and the Buckingham canal in the sea, annihilating everything living. Madras city are really pathetic. Here Sometimes the pollutants are so strong the main pollutant is the sewage from that even the trees along the shores get the city. Fish have virtually disappear­ dried up. ed from these waters and the area serves as a breeding ground for mos­ The highly poisonous organo­ quitoes. The rivers and canals in and phosphorus insecticides which are com­ around Bombay city are other monly used in the paddy fields (eg. examples of the carelessness because Ekatox and Paramar, standard solution of which pollution has become a 100-200 cc/450 litres of water) remain in menace. More than 100 industries in­ the medium for a very lung ti!TIe. These cluding chemical and r"yon factories compounds affect the survival of fi sh are pouring their toxic wastes into the eggs and larvae in our estuaries and Kallu and Vlhas estuaries and these backwaters. Their affects is felt to a waters are so polluted that no fish can greater degree on crmt.ceans which live in them. Adding to this, the city's are more susceptible to th.se com· sewers are also opening into these pounds than fishes . Th is may be one . areas. It is reported that fish catch reason for the d ecline h the prawn around Bombay has cons iderably de­ fishery of backwaters in recent years. clined in recent years. The industrial growth and urbaniz­ Control and rcg :.Ilation ation is now becoming a problem for Kerala, and as a result the rivers I. Domestic sewage should never be· and Periyar with their adjoining back­ passed untreated into the river. It waters are becoming highly polluted. should at least be treated by such Once well known for its fishes, the simple methods as settling, which Ka llayi river is now a polluted stream reduces the polluting effect by because the effluence from the Mavoor about 50%. The se wage after SE di­ rayons factory is discharged into it. The mentation should be treated biologi­ area between the factory and Beypore cally and then oxidised .

21 Seafood Export Journa l' 2. Sources of industrial pollution in r·_·_·_·_· our -rivers are increasing rapidly. The most economic way of,reducing pollution is to incorporate the waste­ ~ ORIENT TO ORIENT treatment processes at the time of construction of plants. Normally it proves to be very expensive to introduce it in the p r ocess later on. TOYO SEAFOODS 3. A c~untry like India situated as it is in the tropical zone should take COMPANY, Ltd. advantage of the bright sunshine • and high ,ir temperature for purify­ ing the water used in industries. which could be utilized for irrigation or over and over again in the !IMPORT industries. FROZEN SHRIMPS 4. For better dilution it is preferable to · LOBSTER HEAD store the effluents and sewage dis­ • charge at the time when the flow of • FROG LEGS river is 10 wand then release it at • OTHER MARINE PRODUCTS the time when the flow is g r eater. I 5. Legislation for the control of pollu­ i tion is absolutely essential to avoid inter-state disputes. The formation i npOH of a high powere d body like the Pollution Control Board is very • FISHING TRAWLERS essential if the r ivers are to be kept i • FREEZING PLANTS free from pollution. • ALL KINDS OF FISHING Over and above this. it is high time GEARS AND EQUIPMENTS 10 educate the common man about the hazardous effects of aquatic pollution. I It will be of much help to create an awareness amongst the public about this man-made evil. So far. there have been I om~ I no serious efforts to assess the hazards ·caused by pollution of our waters. Even t All technical know-how thoug h marine pollution is not very serious in India as compared to in­ dustrially advanced nations . we cannot Addre"s : neglect it. There are very few agencies ISHIKAWA BLDG .. in India which have initiated some steps 20- 1. 2 CHOME. to ass ess the seriousness of this menace MISAKT' CHO, CHIYO[)A' KU in our country. A new project which ITOKYO . JAPAN. is being organized at the Central Marine Telephone: Cable Address Fisheries Research Institute for making 264 - 4370 "TOYOS£FOOD T o«:YO" an assessment of pollution and its effect on aquatic living resources should be considered a welcome move. •

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