FAMOUS INCIDENTS OF WATER POLLUTION

FAMOUS INCIDENTS OF WATER POLLUTION

Coliform Bacteria

The first caussal epidemiological connection Nwon human facces and diseases was made by John Snow in 1854 when he unrevealed the men of London chlorea epidermie by abserving that the common link between all the victims in the Broad Street area was that they obtained their drinking water from the same well. Today we know that coliform bacteria make up something like one-fifth to one-third of the average person's wastes and billions of them are released to the sewage systems everyday. They cause cholera. typhoid fever and gastroenteritis. chlorination of water is the only remedy but we hould not forget that chlorination may pose health hazards of its own.

Nitrates

Nitrates occur naturally in water at low levels. However, heavy application of artificial fertilizers most of which contain nitrogen in the form of urea may become a health problem. Nitrate levels 10 mg/l in water can cause methemoglobinemia known as 'blue baby'. Nitrate levels as high as 40 mg/l have been found in some parts of Midwest.

Mercury

(Minamata Disease, Japan)

In 1956, an epidemic of organic mercury poisoning broke out in Minamata, a small town of 50,000 residents located on the coast of Kyushu, Japan's southermost Island.

The afflicting symptoms of Minamata are madness, muscle spasms, convulsions that arch the body like a taut bow, paralysis, loss of speech and vision, and in many cases the crippling of arms and legs. In the final stages.

the victims muscles waste away and they become comatose. They loose all emotional control and eventually pass from coma to death.

Arsenic Poisoning in West Bengal (India)

In a survey made from 1987 to 1996, seven districts of West Bangal-Malda, Murshidabad. Bardhaman, Nadia, Hooghli, 24-Parganas (North) and 24-Parganas (South) arsenic has been found in groundwater above maximum permissible limit (0.05 mg 1) recommended by WHO (Mandal et al., 1996). According to the estimates of School of Environmental Studies, Jadavpur University. more than 1.0 million people are drinking arsenic contaminated water and more than 2,00.000 people have arsenical skin lesions.

Leucomelanosis as white and black spots on side by side also develops in many patients. Diffuse with modular keratosis on palm and sole in another sign of moderately severe toxicity. Rough and dry skin often with palpable nodules (spotted keratosis) on dorsal surface of hands, feet and legs are symptoms of severe arsenic poisoning. Complications like liver enlargement (hepatomegaly), spleen enlargement (splenomegaly) and fluid in abdomen (ascitis) are seen in several cases. Squamous cell carcinoma, basal cell carcinoma, carcinoma of lung, uterus, bladder. genitourinary tract have also been observed in advanced neglected cases suffering for more than ten years.

Damage of Fisheries

Occurrence of fish and fish migration from polluted rivers become a regular feature. The Hooghly esturary in West Bengal was once considered as the spawning ground for the Indian salmon, Hilsha. Now Hilsha has totally vanished from these waters due to pollution of estuaries. Episodes of fish have been reported from Trombay basin and Periyar estuary in Kerala. Fish productivity has been reduced in Chalier river near Calicut, 16 rivers near Brajranagar Damoder near Asanol, Mahi near Baroda. Chambal near Kotaand Ganga at several places. Massive destruction of aquatic flora and fauna has been reported from river Kallu near Kalyan.

Pesticide Dilemma

Most of the synthetic pesticides are known to liquidate a vital function central nervous system of the target organism. The lack of specificity of persticides has given rise to a variety of ecotoxicological problems of which the most

significant one is the toxicity of insecticides a weedicides to man, domestic animals, fish, birds and wild life. They have assumed tragic dimension as was evident from the episodes of huma poisoning by parathion in Cochin in 1955, the epilepsy in Sitapur and Hardoi districts of UP in 1977 and the Handi Godu syndrome of Karnataka in 1978 resulting in paralysis of poor villagers. Other health hazards associated wit pesticides are headache, vomiting, cough, chest pain, abdomen pain, diarrhoea and depression.