How long does it take pesticides to break down?
How long a pesticide lasts in the environment is determined by a number of factors including (1) how much is introduced and how it is distributed (2) its reactivity in the environmental media, and (3) the conditions of the media. Pesticide persistence is often expressed in terms of half-life. This is the time required for one-half the original quantity to break down. Pesticides can be divided into 3 categories based on half-lives: non persistent — less than 30 days; moderately persistent — 30 to 100 days; and persistent — greater than 100 days. Because half-life values can vary considerably depending on environmental conditions, they are often reported as a range for each media.
