Improper disposal of hazardous waste causes adverse effects on human health and the environment. The normal practices of waste disposal such as insanitary open dump, land filling, discharge in water courses, or open-pit burning will need modification when dealing with hazardous wastes. The principle hazard of improper waste disposal is contamination of soil and groundwater. This arises largely from the waste containing hazardous substances deposited in landfills or on the ground.
With regard to hazardous waste disposal sites, at least five different routes of human exposure are possible:
direct ingestion through drinking
inhalation of contaminants that volatilize from heated water
absorption through the skin during washing and bathing
ingestion through consumption of goods derived from plants or animals exposed to polluted groundwater, and
absorption through the skin when handling contaminated soil.
A worldwide awareness has been created amongst the public against the improper and uncontrolled dumping of hazardous wastes. Such practices have brought about the death of livestock and ill-health in humans. Some of the examples of improper disposal of hazardous wastes are given below.
During the seventies more than 250 houses were built in the Netherlands in the municipality named Lekkerkerk on a belt where hazardous and toxic waste had been dumped. After nearly ten years, the ill effects of dumped hazardous waste were noticed by the residents of that area and about 150,000 tonnes of the polluted soil had to be dug out and disposed of. The total cost of the remedial action was about 200 million Dutch guilders.
In Japan, zinc mining industry at Kamioka discharged effluents containing toxic material without treatment into the Zintsu River. Water from the river was, and continues to be, used for drinking and irrigation. In 1919, a thirty-five year old patient is said to have exhibited symptoms similar to those of Itai-Itai disease, which is now known to be caused by cadmium poisoning. In 1955, Itai-Itai disease was reported to the Society of Medicine, yet only in 1963 did the Ministry of Public Health and Welfare organise a survey committee on this pollution associated disease. It took another ten years before the Japanese Government announced official findings on Itai-Itai disease, linking it to health damage caused by cadmium
In another case, in Hamburg city of West Germany, during 1935 to 1971, about 150,000 m3 of waste oil as liquid chemical waste and 50,000 drums of solid chemical waste was dumped along with the city refuse in Georgswerder landfill site. The total area of the site is about 42 hectares and it is 40 m high. In 1983, dioxine was identified in the oily leachate from the landfill site. The cleaning up cost of this site would be more than 100 million Deustche Mark.
One of the most alarming case came into limelight in 1988 when village Bichhri of Udaipur district suffered a heavy toll because of water pollutants released from Silver Chemicals Factory. The water has become red all over from the dye stuff waste released by the factory. Drinking this water causes vomiting. It is worthless for all irrigation purposes. Grass cant grow near the pools containing this water. Today, in December 1990, the water continues to be contaminated, as the amount of pollutants is virtually 1.5 lakh times the standards of safety prescribed by an Aligarh Muslim University study. According to the Observer, the authorities have sued the culprits but procedures of court are too long to provide instant respite to residents of Bichhri village.
Cyanide is one of the raw materials used for electroplating and heat treatment operations of metals. The waste generated as sludge from these operations contains high concentration of cyanide.
A considerable number of large and small scale units, using cyanide as raw material, are located near Madras. Since at present, there is no control over the disposal of hazardous wastes, they are being disposed off indiscriminately. Recently, on 21 August 1989, an incident of cyanide dumping has come to light in Madras with the death of a number of buffaloes. Based on the police reports, the Tamil Nadu Pollution Control Board served a show cause notice to M/s. T. I. Cycles in Madras. After investigations, it was traced that the unit in question had dumped their cyanide bearing waste near Ezhilnagar canal.
This resulted in pollution of canal water and subsequently the death of buffaloes confirmed that the death was due to cyanide contamination. The unit has, however, admitted that they had handed over vast quantities of cyanide waste to the contractor for dumping into the sea at a specified distance of 7 kilometer from the sea shore. The contractor dumped the waste on. Ezhilnagar canal bank. An analysis of canal water showed that the cyanide content was as high as 210 milligrams per litre. Since the canal passes through a low income group colony, the pollution of canal water could have resulted in loss of human life, had it gone undetected.