DDT Dichlorodiphenyltrichlorethane

One of the dirty dozen chemicals called POPS (persistent organic pollutants). The first, most famous, most successful, and most notorious of the synthetic insecticides. It was first synthesised chemically in 1873 but its insecticidal properties were not discovered until 1939, by the Swiss entomologist Paul Müller, who was awarded the 1948 Nobel Prize in Medicine. DDT proved to be of enormous value in the control of insect vectors of human diseases, such as malaria, typhoid, and cholera. Scientists still speculate whether DDT or penicillin has saved the most human lives. DDT also controlled the vectors of many animal diseases, as well as numerous crop pests. The latter included major pests such as Colorado beetle of potato, boll worms of cotton, and codling moth of apples. It should be remembered that these pests had previously been treated with compounds of lead, arsenic, mercury, and cyanide. DDT was both cheap and persistent. The peak production in the USA was in 1961 when 175 million pounds were produced. However, its widespread abuse led to serious environmental damage and fears for human health. Because DDT is water-insoluble, but fat-soluble, it accumulates in body fat, and a phenomenon called biomagnification leads to increasing concentrations of DDT up the food chain. Humans, as well as many carnivorous birds are at the top of their food chains and accumulate the highest levels. A further problem was the development of DDT-resistance in target insects. This was the first example of an unstable insecticide. Another problem concerned the killing of non-target and beneficial insects, such as pollinating bees, and the agents of biological control. In 1973, its use in the USA was banned, and many other countries followed this example. It is now banned by international treaty except in areas where its use is essential for the control of malaria. Death

In systems terminology, death is a loss of behaviour, while decay is a loss of structure. Life is an emergent property, and death is the irrevocable loss of that emergent.

Growing Soilless

Growing Soilless

This is an easy-to-follow, step-by-step guide to growing organic, healthy vegetable, herbs and house plants without soil. Clearly illustrated with black and white line drawings, the book covers every aspect of home hydroponic gardening.

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