The Hidden and External Costs of Pesticide Use
A fair evaluation of the net benefits provided by pesticides is essential to feed the current debate on their benefits and adverse consequences. Pesticides provide many benefits by killing agricultural and human pests. However, they also entail several types of costs, including internal costs due to the purchase and application of pesticides, and various other costs due to the impact of treatments on human health and the environment. Here, we provide a comprehensive review of these costs and their evaluation. We define four categories of costs: regulatory costs, human health costs, environmental costs and defensive expenditures. Those costs are either internal to the market, but hidden to the users, or external to the market and most often paid by a third party. We analysed 61 papers published between 1980 and 2014, and 30 independent dataset. Regulatory costs reached very large values, e.g. US$4 billion yearly in the United States in the 2000s. However, if all regulations were respected, these costs would have jumped to US$22 billion in this country. Health costs studies generally did not take into account fatal cases due to chronic exposure such as fatal outcomes of cancers. Doing so would have increased estimates of health costs by up to tenfold, e.g. from US$1.5 billion to US$15 billion in the United States in 2005.