Methyl isocyanate animals

The other source of water pollution is toxic chemicals, of which the chemical and petroleum industries are a major source. The oil spiU from the Exxon Valdez in Alaska and the methyl isocyanate release from Bhopal, India, are the most widely known examples. Here the overall problem is that chemicals are released that are not normally found in nature, and consequently plants and animals have no defenses against them. 

Adkins, B., O Conner, R.W., Dement, J.M. (1987). Inhalation exposure system used for acute and repeated-dose methyl isocyanate exposure of laboratory animals. Environ. Health Perspect. 72 45-51. 

Nemery, B., Dinsdale, D., Sparrow, S. (1987). Toxicity of inhaled methyl isocyanate in experimental animals a review of studies published less than two years after the Bhopal disaster. Bull. Eur. Physiopathol. Respir. 23 315-22. 

Certain chemical disasters have prominent places in medical history. In 1976, a chemical reactor explosion in Seveso, Italy, released 2,3,7,8-tetrachlorodibenzo-p-dioxin, which contaminated thousands of acres, killed 100,000 animals, and caused the evacuation of hundreds of people (Melius and Binder 1989). In 1984 in Bhopal, India, a carbamate pesticide plant released 30 tons of methyl isocyanate, causing more than 3,000 deaths and 50,000-300,000 injuries (Melius and Binder 1989). The Three Mile Island and Chernobyl nuclear accidents during the 1980s were the culmination of a string of eight nuclear accidents since 1952 (Melius and Binder 1989). Other chemical disasters severely affected local communities but did not generate widespread attention (De La Paz 1997 Withers 1988). 

Methyl isocyanate exhibited toxicity in two phases 40 ppm exposure caused death of a majority of animals within 1-2 days or between 7 and 21 days after exposure. Varma et al. (1988) observed that injection of 2 mg dexamethasone/kg before exposure inhibited the toxicity within the first... 

December 2nd, 1984 Bhopal, India Release of 23 2 t of methyl isocyanate water used for cleaning initiated an exothermic reaction with temperature and pressure rise 16,000 persons killed, 170,000-600,000 poisoned >4,000 animals died... 

Other disasters at chemical plants followed in 1976 at Seveso (Italy) there was a dioxin escape which polluted over 4000 acres of farmland, killed 100 000 grazing animals and led to the evacuation of 1000 people. Later (1984) in India a release of 40 tonnes of methyl isocyanate from a batch operation at Bhopal resulted in 40 000 deaths and 100 000 injuries. Incidents such as these would have either been avoided or extensively mitigated had the processes been intensified. In the Flixborough case, a very much smaller vapour cloud would probably have been incapable of developing the shock wave which proved to be so damaging. A continuous intensified version of the Bhopal reactor may still have caused fatalities, had the contents been released, but there would have been very many less than actually CKCurred. 

---