Aldicarb food poisonings in California, 1985-1988: toxicity estimates for humans.

Three outbreaks of food poisoning involving watermelons or cucumbers and caused by the carbamate pesticide aldicarb occurred in California between 1985 and 1988. For each outbreak, and for an outbreak of aldicarb poisoning associated with English cucumbers previously reported in the literature, dosages of aldicarb sulfoxide that caused the illnesses were estimated. Estimated dosages ranged between 0.0023 [corrected] and 0.06 mg/kg body weight, and most were well below the 0.025 mg/kg Lowest Observed Effect Level (LOEL) for subclinical blood cholinesterase depression previously reported for humans. These findings are consistent with aldicarb sulfoxide (ASO) illnesses that have occurred in other states. Aldicarb appears to be more toxic than previously suspected. Scientific and regulatory implications are discussed.