CAREX Canada, Faculty of Health Sciences, Simon Fraser University, Harbour Centre Campus, Vancouver, BC, Canada.
Department of Geography and Planning, University of Toronto, Toronto, ON, Canada.
Ann Work Expo Health. 2021 May 3;65(4):377-389. doi: 10.1093/annweh/wxaa109.
Certain pesticides have been associated with adverse health outcomes including cancer and reproductive harms. However, little is known about the prevalence of occupational pesticide exposure among agricultural workers in Canada. The purpose of this study was to estimate the prevalence and likelihood of occupational exposure to pesticides in Canada's agricultural industry, using three commonly used, potentially carcinogenic pesticides [chlorothalonil, 2,4-dichlorophenoxyacetic acid (2,4-D), and glyphosate] as an example.
Estimates were calculated using the Canadian Census of Population and the Census of Agriculture. The number of workers and the proportion of farms applying 'herbicides' or 'fungicides' by farm type was estimated using survey data from the Census of Agriculture. These values were multiplied to yield the potential number of workers at risk of exposure. Likelihood of exposure (i.e. exposed, probably exposed, and possibly exposed) was then qualitatively assigned using information on crop type, primary expected tasks, crop production practices, and residue transfer data. Additional agricultural workers who are at risk of exposure but not captured by the Census of Agriculture were identified using the 2016 Census of Population.
An estimated range of 37 700-55 800 workers (11-13% of agricultural workers) were exposed to glyphosate in Canada while 30 800-43 600 workers (9-11%) and 9000-14 100 (2.9-3.2%) were exposed to 2,4-D and chlorothalonil, respectively. Approximately 70-75% of workers at risk of exposure were considered probably or possibly exposed to any of the pesticides. Glyphosate exposure was most common among workers in oilseed (29% of oilseed farm workers exposed) and dry pea/bean farms (28%), along with those providing support activities for farms (31%). 2,4-D exposure was most common in corn (28%), other grain (28%), and soybean farms (27%), while chlorothalonil exposure was more likely among greenhouse, nursery, and floriculture workers (42%), workers on farms (28%, for occupations not captured by the Census of Agriculture, specifically), and those providing support activities for farms (20%). Regional variations broadly reflected differences in farm types by province.
This study estimated the prevalence of occupational exposure to three pesticides in Canada. Seasonal and temporary agricultural workers, which were captured by the Census of Agriculture, contributed to many additionally exposed workers. A large percent of the workers who were considered at risk of exposure were considered probably or possibly exposed, indicating a need for enhanced data collection and availability on pesticide use data in Canada. The study's methods can be applied to estimate workers' exposures to other pesticides within the agricultural industry.
某些农药已被证实与健康不良后果有关，包括癌症和生殖危害。然而，人们对加拿大农业工人职业性农药暴露的流行程度知之甚少。本研究旨在使用三种常用的潜在致癌农药（百菌清、2,4-二氯苯氧乙酸（2,4-D）和草甘膦）作为示例，估算加拿大农业中农药职业暴露的流行率和可能性。
使用加拿大人口普查和农业普查的数据进行估计。根据农业普查的调查数据，按农场类型估算使用“除草剂”或“杀菌剂”的工人数量和农场比例。这些数值相乘得出可能接触农药的工人人数。然后根据作物类型、主要预期任务、作物生产实践和残留转移数据，定性分配接触农药的可能性（即接触、可能接触和可能接触）。使用 2016 年人口普查数据确定了未被农业普查捕获但有接触农药风险的其他农业工人。
估计有 37700-55800 名工人（占农业工人的 11-13%）在加拿大接触草甘膦，而有 30800-43600 名工人（占 9-11%）和 9000-14100 名工人（占 2.9-3.2%）分别接触 2,4-D 和百菌清。大约 70-75%有接触农药风险的工人被认为可能接触到任何一种农药。在油籽（29%的油籽农场工人接触）和干豌豆/豆科农场（28%）以及为农场提供支持活动的工人（31%）中，草甘膦暴露最为常见。在玉米（28%）、其他谷物（28%）和大豆农场（27%）中，2,4-D 暴露最为常见，而在温室、苗圃和花卉种植工人（42%）、农场工人（28%，针对未被农业普查捕获的职业，特别是）以及为农场提供支持活动的工人（20%）中，百菌清暴露更为常见。区域差异大致反映了各省农场类型的差异。
本研究估计了加拿大三种农药的职业暴露流行率。季节性和临时农业工人，被农业普查所捕获，为许多额外的接触工人做出了贡献。被认为有接触农药风险的工人中，有很大比例被认为可能接触或可能接触，这表明需要加强加拿大农药使用数据的收集和可用性。该研究方法可用于估计农业行业内其他农药对工人的暴露情况。
