AGRICULTURAL CHEMICAL-SCREENING AND DETECTION OF CHLORPYRIFOS IN FISHES FROM THE APURE DRAINAGE, VENEZUELA

To evaluate aquatic effects of large-scale agricultural operations, we determined agricultural chemical concentrations in muscle tissues fro m nine fish, representing important food species, taken in December 19 93 from the Apure River drainage, Venezuela. In a series of screenings that included carbamates, herbicides, and other pesticides (organopho sphates and chlorinated hydrocarbons), the only chemical detected was the organophosphate chlorpyrifos (=Dursban), in six of seven samples. Chlorpyrifos concentrations in fish flesh were generally 3 to 10 ppb w et weight. These preliminary results suggest that fishes from this are a of the Apure River drainage are not heavily contaminated with persis tent pesticides and do not appear at present to pose a serious food sa fety or human health hazard. However, future monitoring of a broad ran ge of fish species for environmental contaminants is recommended.