Clinical and biochemical changes in chronically exposed organophosphate workers

Health effects of occupational organophosphate exposure were investigated by subjecting 22 workers chronically exposed to an organophosphate pesticide, fenthion (O,O-dimethyl-O-(4-methylmercapto-3-methylphenyl)-phosphorothioate) to clinical evaluation, estimation of serum cholinesterase, serum alkaline phosphatase (SAP), serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT). The mean age of the workers was 31 years and the mean duration of fenthion exposure 8.2 years. Headache (59%), giddiness (50%), ocular symptoms (27%) and paresthesia (18%) were the commonest symptoms. Serum acetylcholinesterase and butyrylcholinesterase levels were significantly lower than in controls. After withdrawing the workers from organophosphate exposure for 3 weeks, the follow-up study revealed absence of transient symptoms. There was no change in their neurological status, and serum acetylcholinesterase and butyrylcholinesterase levels were raised significantly, whereas the other serum enzymes showed no significant change. For monitoring of occupational organophosphate exposure, the importance of both clinical and biochemical parameters is emphasised.