Settling

Pesticide in the particulate phase may be removed from the water layer by settling. Settling transfers pesticide from the water to the sediment layer. The amount of pesticide that is removed from the water via settling is:

$pst_{stl,wtr}=\frac{v_s}{depth}*F_p*pst_{rchwtr}*TT$ 7:4.1.12

where $pst_{stl,wtr}$ is the amount of pesticide removed from the water due to settling (mg pst), $v_s$ is the settling velocity (m/day), $depth$ is the flow depth (m), $F_p$ is the fraction of total pesticide in the particulate phase, $pst_{rchwtr}$ is the amount of pesticide in the water (mg pst), and $TT$ is the flow travel time (days).