Definition: Organochlorines are used in certain spray pesticides; they contain chlorine and carbon amongst other elements. They are sprayed on crops to kill pests, but they also indiscriminately kill other insects in the area that are actually benign or beneficial. They also affect humans, when breathed in they can cause symptoms and general ill-health, such as headaches, dizziness, nausea or vomiting. These pesticides are also detrimental to the environment.