Environmental Toxicology

Environmental toxicology refers to the poisoning of the environment either accidentally or deliberately, leading to the term ecotoxicology being coined by R. Truhart in 1969. The idea of poisoning an environment dates back to the ancient world with the much-highlighted story of the Romans sowing salt over the fields of their defeated enemy Carthage following [Page 610]the destruction of that city in 146 b.c.e. The salinity was to ensure that no crops would grow there, but historians now doubt that the Romans would have done this, owing to the vast cost of salt in the ancient world and the fact that Carthage was refounded as a Roman city soon afterward. However, there remains the possibility that the Romans might have used seawater to destroy some of the fertile fields around Carthage.

Biological warfare has been considered early during the 20th century; however, the concept goes back to medieval and early modern times when there were attempts to pass the bubonic plague to enemies, especially in Renaissance Italy. There were also instances of the poisoning of waterholes by American and Australian settlers to kill indigenous people in their respective countries. The destruction of their food supplies, such as the killing of the vast bison herds which provided much food for the Native Americans, and the kangaroos in the case of the Australian aboriginals, are further examples of environmental destruction. During the Vietnam War, the use of Agent Orange and other defoliants with the specific aim of destroying rainforests where Vietcong guerrillas were hiding, is the most widespread recent use of poisons to deliberately destroy entire ecosystems.

However, the concept of environmental toxicology in the modern era largely came from Silent Spring by Rachel Carson. The book was published in 1962 despite attempts by pesticide companies to prevent its publication. Carson highlighted the accidental side effects from the use of toxins, especially DDT, and fertilizers, which were used by farmers and had the result of killing large amounts of wildlife. She concentrated on researching the side effects from these, which some felt might have led to higher levels of cancer in humans. First alerted to the threat of DDT by a bird sanctuary in Massachusetts whose wildlife had been killed by DDT from an aerial spraying of crops nearby, Carson was able to show that pollutants used in one area could quickly affect another neighboring area, and the destruction of a particular part of the food chain upsets the “balance of nature” and can quickly lead to the destruction of an ecosystem. Chemical companies felt that Carson's work unfairly attacked their products and a few tried to pressure the publisher to stop the book coming out.

Since Carson's book, work by people such as Dr. R. Truhart led to the establishment of the field of eco-toxicology which has been defined as the branch of toxicology which is concerned with the study of the toxic effects, caused either by natural or synthetic pollutants, to the constituents of ecosystems, animals and humans, vegetables and microbial life.

This has focused attention on industrial pollution and discharge from the mines, both deliberate and accidental. The result has been seen near many gold mines where there has been widespread use of cyanide, which has led to the poisoning of the environment, including the water table. The effects have become noticeable around some mines such as those at Kalgoorlie in Western Australia. There had also been much pollution at the Panguna Copper Mine in Bougainville, leading to the local people, including some workers at the plant, to stage a revolt and eventually take control of the island to close down the mine.

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