Exposure of spray operators to paraquat.

322-329. Two field-trials in Malaysian rubber plantations are described in which operators applied paraquat for weed control with hand-operated knapsack sprayers. The extent of systemic absorption was assessed by weekly estimation of urinary paraquat concentrations during and after a 12-week period of continuous spraying. Periodic medical examinations, including chest radiographs, were made before and during the trials and for some weeks afterwards. The conditions of continuous operation with paraquat were probably close to the extremes of exposure likely to occur in any agricultural operation, but the investigations have shown that ordinary care in personal hygiene is sufficient to prevent any hazard from surface injury or from systemic absorption.