Lake Notes Pesticides Everything applied to your yard has the potential to contaminate ground and surface waters. This is particularly true with homes located close to lakes and streams. Pesticides, for instance, are chemicals intended to kill or repel pests and include herbicides, insecticides, fungicides and rodenticides.
Some pesticide residues can contaminate freshwater ecosystems for generations.
As pesticides decompose the breakdown products produced can sometimes be more toxic and affect more organisms than the original pesticide. Some pesticides can bio-accumulate. This means the toxic level of the pesticide increases as it is consumed by each link in the food chain. DDT, which the U.S. banned in 1972, is one of the most famous examples of bioaccumulation. Many of our prized gamefish are considered top predators, making humans who consume contaminated fish at potential risk from bioaccumulation.