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 is the sediment half-life for the pesticide (days).