1Sonoda Women's University Junior College, Amagasaki, Hyogo 661-8520, 2Osaka City Institute of Public Health and Environmental Sciences, Tennoji, Osaka 543-0026, 3Otsuchi Marine Research Center, Ocean Research Institute, The University of Tokyo, Otsuchi, Iwate 028-1102, 4School of Human Sciences, Kobe College, Nishinomiya, Hyogo 662-8505, Japan
To evaluate toxicity in the aquatic environment, a new, rapid and effective screening test has been required. In the present study we describe the procedure of a screening test based on the inhibition of in vitro acetylcholinesterase activity, and report the application to some water samples from aquatic environments, which contain trace amounts of a variety of organophosphorus compounds.
A porous polystyrene cartridge PS-2 concentration system was used for preparation of water samples in the field for toxic evaluation. Dichlorvos inhibited 86％ of acetylcholinesterase activity, while fenitrothion, diazinon and iprobenfos showed either less or no inhibitory effect. Organophosphoric acid triesters which contain an aryl group, e.g. triphenyl phosphate, tricresyl phosphate and cresyl diphenyl phosphate, showed higher inhibition than those without an aryl group.
Comparison of inhibition of acetylcholinesterase in river water samples from Hyogo (an urban area) and Iwate (a rural area) indicated that the former rivers were more highly polluted in organophosphorus compounds than the latter ones. There was a high inhibitory effect on acetylcholinesterase by concentrated samples of raw sewage and this effect gave a good dose-response relationship.