Bioconcentration of the insecticide pyridaphenthion by the green algae Chlorella saccharophila

A study was undertaken to examine the uptake of the organophosphate insecti cide pyridaphenthion in the chlorophyta Chlorella saccharophila, Algae cult ures were exposed to the initial nominal concentration 10.0 mg 1(-1) pyrida phention during seven days. The insecticide bioconcentrates in the biomass to the highest level of 441.5 +/- 25.9 mg kg-l on the fifth day of exposure and was followed by a decrease to 76.6 +/- 5.1 mg kg(-1) on the seventh da y. A model was constructed to describe the dynamic process, which estimated a bioconcentration factor (BCF) equal to 28. The study demonstrates the po tential of accumulation of pyridaphenthion in aquatic organisms and helps t o expand the pyridaphenthion toxicity database. The replacement of fenitrot hion by pyridaphenthion concerning their use in rice flooded cultures is di scussed. (C) 2001 Elsevier Science Ltd, All rights reserved.