The monitoring of pesticides in water has been carried on in various areas since World War II. Some of the monitor networks, backed by analysis laboratories, are quite extensive. The accumulated data show how and when certain pesticides move from target areas into other parts of the environment. Ponds and catch basins sometimes show measurable amounts of pesticide residues from water leaving fields. Although most organic insecticides are hydrophobic and almost insoluble in water, they can become attached to materials suspended in water; but, after these materials settle, the remaining amounts of insecticide residues usually become negligible. This confirms the ...(100 of 17649 words)