NEUROPSYCHOLOGICAL EFFECTS OF LONG-TERM EXPOSURE TO ORGANOPHOSPHATES IN SHEEP DIP

Organophosphate-based pesticides are widely used throughout the world. The acute effects of over-exposure to such compounds are well known. Concern has also been expressed that long-term exposure may result in damage to the nervous system. In a cross-sectional study, we compared neuropsychological performance in 146 sheep farmers who were exposed t o organophosphates in the course of sheep dipping with 143 non-exposed quarry workers (controls). The farmers performed significantly worse than controls in tests to assess sustained attention and speed of info rmation processing. These effects remained after adjustment for covari ates. The farmers also showed greater vulnerability to psychiatric dis order than did the controls as measured by the General Health Question naire. There were no observed effects on short-term memory and learnin g. Repeated exposure to organophosphate-based pesticides appears to be associated with subtle changes in the nervous system. Measures should be taken to reduce exposure to organophosphates as far as possible du ring agricultural operations.