Abstract
The kinetic analyses for evaluation of the uptake and decomposition of pesticides by algae were pursued by using the green alga Selenastrum capricornutum and organophosphorus insecticides. The alga-induced disappearance rate constants (kA) of fenitrothion, diazinon and cyanophos in each exponential growth stage, steady stage and whole growth period of algae were estimated independently of other disappearance rate constants originated from light and medium (kν, and kM, respectively). The kA values in the steady stage were 1.3-2.5 times larger than those in the exponential growth stage in all chemicals. The kA values during the whole growth period were between those in the exponential growth stage and those in the steady stage, being closer to those in the steady stage. The kν and kM values were also estimated for comparison in contribution for the disappearance.
