Exposure risks to pesticide applicators posed by the use of electric backpack sprayers and stretcher-mounted sprayers in orchards

Abstract

The introduction of the pesticide registration system in pesticide risk assessments has promoted the scientific and safe use of pesticides, and the assessment of occupational exposure risk. In the present study, we performed an experiment in a citrus orchard subject to normal orchard management practices. By measuring the exposure of applicators’ (farmers and technicians) body parts to 45% malathion emulsifiable concentrate during its application using electric backpack sprayers (0.25 KPa) and stretcher-mounted sprayers (1.5 KPa), the unit exposure (UE) was determined. The risks of exposure for pesticide applicators who adopted five different protective measures (A: no personal protective equipment (PPE), i.e., no clothes, no gloves, no caps, and no socks; B: short-sleeved top and shorts; C: short-sleeved top, shorts, and a single pair of gloves; D: short-sleeved top, shorts, a single pair of gloves, and a cap; E: long-sleeved top, long pants, a single pair of gloves, and a cap) were also assessed. The results were as follows: 1) The total levels of exposure for pesticide applicators using electric backpack sprayers and stretcher-mounted sprayers were 3613.63 µg and 5654.28 µg, respectively. When electric backpack sprayers were used, the body parts that had the highest exposure were the head (13.8%), hands (19.9%) and back (14.0%), and when stretcher-mounted sprayers were used, the hands (32.5%) and lower legs (21.1%) had the highest level of exposure; 2) In the absence of PPE, the UE values for farmers who used electric backpack sprayers and farmers who used stretcher-mounted sprayers were significantly different. However, when PPE was used, the difference in UE values between the farmers using the two different types of sprayers was not significant; 3) When protective measure A was adopted, the risk quotient (RQ) values of the farmers and technicians who used electric backpack sprayers for the application of malathion were 1.44 and 0.54, respectively; the corresponding RQ values when protective measure B was adopted were 0.97 and 0.28, respectively. When stretcher-mounted sprayers were used for the application of chlorpyrifos, the RQ value of the farmers who adopted protective measure E was 0.43 while other types of PPE use resulted in RQ values greater than 1. In contrast, the RQ value for technicians was 1.62 when protective measure A was used and 1.02 when protective measure B was adopted, whereas other types of PPE use resulted in RQ values less than 1. Therefore, besides increasing the awareness of personal protection among pesticide applicators, improvement in the management of pesticide use and the enhancement of standard operations are of practical significance for controlling occupational exposure to pesticides.

Keywords:

• Pesticide application
• operator exposure
• unit exposure
• risk assessment

Additional information

Funding

This study was supported by National Natural Science Foundation of China (21607134).