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Pesticides That Cause Water Pollution

Pesticides are commonly used in agriculture to protect crops from the damaging effects of insects. These pesticides get into the soil and eventually into the underground water, streams, and lakes. However, the agriculture industry isn̵7;t the only source of water pollutants. People living and working in urban areas also contribute to pesticide pollution when they use pesticides in their homes or in public places. The three common classes of pesticides that end up in water are organophosphates, pyrethroids, carbamates, and triazines.

Organophosphates
- Organophosphates are chemical insecticides that contain phosphorus. The way they work is to block the activity of an enzyme that degrades a neurotransmitter called acetylcholine. Releasing acetylcholine so it binds to another cell is how nerves communicate with each other and with muscles. A build-up of acetylcholine results in nerve damage and death. The organophosphates diazinon and chlorpyrifos were widely used in the 1990s, but have been withdrawn since the discovery that they cause health problems in children.
Carbamates
- Carbamates are another class of insecticides that works by inhibiting acetylcholinesterase, the enzyme that degrades the neurotransmitter acetyl choline. They are nerve poisons. Common carbamates are aldicarb, carbofuran, and oxamyl. Aldicarb is used to protect potatoes. Carbamates are soluble in water and so are not good at staying in the soil. If they are not degraded in the top soil, they will trickle down and eventually get into groundwater. Carbamates are the most common chemical pollutants in groundwater wells.
Pyrethroids
- Pyrethroids are a class of insecticides that work by inhibiting the sodium channels on nerve cells. Nerve cells, or neurons, communicate by releasing neurotransmitters that bind to a neighboring cell. Binding of a neurotransmitter to the target cell causes protein channels on the membrane of that cell to open, which allows sodium ions to flow into the cell. This flow is the first step of receiving a signal from a neighbor. Pyrethroids are not as toxic to humans and other mammals are they are to fish and invertebrates. Pyrethroids are found in insecticides used in homes for ant control, on lawns and gardens.
Atrazine
- Another pesticide that pollutes water is atrazine. It is a common weed killer, or herbicide. Atrazine is in the triazine class of herbicides. It kills plants by disrupting the proteins required for photosynthesis, so that plants cannot produce their own food. In Hawaii, atrazine was widely used on thousands of acres of sugar cane fields. In humans, atrazine exposure has been linked to cancer, alterations in sex hormones, and birth defects. Atrazine can stay in water for years.

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