Pesticides - Used in Agriculture & at Home


Man-made chemicals intended to prevent, destroy, or repel pest organisms. The chemicals include herbicides, insecticides and fungicides. The pests include plants, insects (and other animals) and fungi.


Why does it cause pollution?

Pesticides cause pollution because they sometimes destroy or injure non-target species. They work by altering the way a creature's body works. For example, some insecticides prevent the production of cholesterol in the insect's body. Cholesterol is a building block of vital chemicals in both insects and mammals. Toxic levels can result in the death of the organism or a change in the way it grows. Pesticides are harmful to animals that live in the water when the pesticide ends up in the water, because animals that live there are in direct contact with these chemicals.

Humans can also be at risk, particularly if they get their drinking water from surface water. In the Barataria-Terrebonne Basin, we get a lot of our water from surface waters. Some cities that get their water from surface water include Houma, Thibodaux, and New Orleans


How does it get into the water?

Pesticides are sprayed onto plants or around houses. Many plants are soluble in water. So, when it rains, the pesticides dissolve in the rainwater and move off the land as runoff into bayous and streams. Pesticides that are insolublemay be mixed with some sort of oil. This means they may have a lower density than water and will float on top of water when it rains, just like an oil slick.


What land uses are the source of this type of pollution in the B-T Basin?

  • Agricultural Runoff
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