Determination of potential dermal and inhalation operator exposure to malathion in greenhouses with the whole body dosimetry method

One of the steps during the authorization process of plant protection products (PPP) in the European Union is to evaluate the safety of the operator. For this purpose, information on the probable levels of operator exposure during the proposed uses of the PPP is required. These levels can be estimated by using existing mathematical models or from field study data. However, the existing models have several shortcomings, including the lack of data for operator exposure levels during spray applications by hand lance, especially in greenhouses. The present study monitored the potential dermal and inhalation operator exposure from hand-held lance applications of malathion on greenhouse tomatoes at low and high spraying pressures. The methodology for monitoring potential exposure was based on the whole body dosimetry method. Inhalation exposure was monitored using personal air pumps and XAD-2 sampling tubes. For the monitoring of hand exposure, cotton gloves were used in two trials and rubber gloves in another three. The total volumes of spray solution contaminating the body of the operator were 25.37 and 35.83 ml/h, corresponding to 0.05 and 0.07% of the applied spray solution, respectively, in the case of low pressure knapsack applications and from 160.76 to 283.45 ml/h, corresponding to 0.09-0.19% of the spray solution applied, in the case of hand lance applications with tractor-generated high pressure. Counts on gloves depended on the absorbance/repellency of the glove material. The potential inhalation exposures were estimated at 0.07 and 0.09 ml/h in the case of low pressure knapsack applications, based on a ventilation rate of 25 l/min. Both potential dermal operator exposure (excluding hands) and potential inhalation exposure were increased by a factor of similar to7 when the application pressure was increased from 3 to 18 bar in greenhouse trials with a tractor-assisted hand lance, the rest of the application conditions being very similar.