Exposure of Workers to Pesticides

Abstract

Values for dermal and respiratory exposure and for total exposure in terms of fraction of toxic dose were determined for 31 different work activities involving 10 different pesticides. There were wide ranges in exposure level for a given work activity with a specific pesticide, depending on the environmental conditions, particularly wind and technique of the operator; but other factors could not be excluded. Also, for a given pesticide there was a significant variation in hazard depending upon the type of work activity involved. Various phases of an operation often produced different levels of exposure. Generally, the loading operation was the most hazardous part of the spraying or dusting cycle. Exposure also depended upon the method of application. Not only was the hazard related to the length of time worked, but the use of dusts or fine aerosols rather than sprays greatly increased respiratory exposure. As reported in previous exposure studies, the potential dermal exposure to each compound in every work situation studied was much greater than the potential respiratory exposure. However, the practical importance of this potential difference must be viewed in light of the fact that chemicals given at equivalent doses are absorbed more rapidly and more completely from the respiratory tract than through the skin. The results from the present study were generally in good agreement with those published previously in those instances in which direct comparisons were possible. The present results indicate that, in general, workers using pesticides in agriculture and public health vector control are exposed to relatively small fractions of the toxic dose each day. These findings are consistent with the idea that pesticides can be used safely provided recommended precautions are followed. However, the relatively high exposure values associated with a few of the more toxic pesticides (such as endrin, parathion, and TEPP [tetraethyl pyrophosphate]) indicate that even minor lapses in adherence to safety precautions might be sufficient to allow poisoning to occur.