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# Degradation

Pesticides in both the particulate and dissolved forms are subject to degradation. The amount of pesticide that is removed from the sediment via degradation is:

            $$pst\_{deg,sed} = k\_{p,sed} \*pst\_{rchsed}$$                                                              7:4.2.8

​where $$pst\_{deg,sed}$$ is the amount of pesticide removed from the sediment via degradation (mg pst), $$k\_{p,sed}$$ is the rate constant for degradation or removal of pesticide in the sediment (1/day), and $$pst\_{rchsed}$$ is the amount of pesticide in the sediment (mg pst). The rate constant is related to the sediment half-life: 

            $$k\_{p,sed} =\frac{0.693}{t\_{1/2,sed}}$$                                                                                 7:4.2.9

where $$k\_{p,sed}$$ is the rate constant for degradation or removal of pesticide in the sediment (1/day), and $$t\_{1/2,sed}$$ is the sediment half-life for the pesticide (days).