Pesticide Exposure and Pesticide Health Effects

by

David F. Goldsmith

• LAST REVIEWED: 10 March 2015
• LAST MODIFIED: 10 March 2015
• DOI: 10.1093/obo/9780199756797-0147

Introduction

Pesticides are chemical agents designed to kill pests such as insects or rodents, or they are chemical products used either to prevent damage to crops or to prevent the growth of microbial agents capable of transmitting infection. In the United States, a pesticide is also any substance or mixture intended for use as a plant regulator, defoliant, or desiccant (drying agent) on a crop. Pesticides differ from other environmental contaminants, like lead or other waste products, because pesticides are manufactured to either kill or prevent harm. Pesticides have societal benefits, but can also harm public health. Because of the wide variety of information sources available for pesticide exposure and health effects, and the multiple government agencies involved with pesticide registration, enforcement, and monitoring, this paper provides a comprehensive overview of some of these sources in one document. First, this paper provides a review of information sources related to pesticide exposure, including information on annual pesticide usage in agricultural, residential, commercial, institutional, and military settings; and sources for health effects data related to pesticide exposure. Second, this review outlines sources of information relevant to environmental pesticide contamination of air, water, soil, and food supplies. This article also considers acute and chronic exposure routes, carcinogenicity, neurotoxicity, dermal toxicity of pesticides, developmental/reproductive and adult health effects of pesticides. Most of the sources are in English, but sources in other languages are also relevant to understanding the extent of the health problems; every effort is made to direct readers to those sources where we can find them. This paper would not be as insightful had it not been for the generous comments of Kristin Rury, MPH.

General Pesticide Regulation Overview

The US National Library of Medicine (NLM) is home for the Toxicology and Environmental Health Information Program (TEHIP). This site includes links to databases, tutorials, bibliographies, and other scientific and consumer-oriented resources on pesticides and on many other environmental hazards. TEHIP also is responsible for the Toxicology Data Network (TOXNET^®), an integrated system of toxicology and environmental health databases. Because TEHIP is tied to the published medical and public health literature via the NLM, it is a well-regarded source of information. Care needs to be taken because some databases are updated more (or less) frequently, and US Environmental Protection Agency (EPA) periodically cancels the registration or approves new pesticide products for the American market. There are several federal agencies in the United States with pesticide exposure, toxicology, and other health information. They include the EPA, the National Institute of Environmental Health Sciences (NIEHS), the Department of Agriculture (USDA), the Food and Drug Administration (FDA), the National Institute for Occupational Safety and Health (NIOSH), and the Centers for Disease Control and Prevention (CDC). Two federal laws govern registration and regulation of pesticide chemicals: the Federal Insecticide, Fungicide, Rodenticide Act (FIFRA) and the Food Quality Protection Act (FQPA). The EPA administers both FIFRA and FQPA. Schierow and Esworthy 2012 explains how the EPA and FDA regulate pesticide levels on fresh and processed foods. The US Department of Agriculture, through its state Agricultural Extension Service provides information on pesticide uses in relation to the production of specific crops. Under the authority of FIFRA and FQPA, the EPA regulates what pesticide active ingredients can be applied to agricultural crops, the amount of the pesticide chemical residues permitted on fresh and processed foods, the pre-harvest interval (the amount of time needed after pesticide application prior to harvest), the personal protective equipment (PPE) required by workers handling the pesticide, and the re-entry interval before workers can resume working in a treated field. In the United States, the product label contains information on the appropriate application method(s) and application rate, how much of the pesticide active ingredient is permitted on each crop, and which pests it can be used to treat or prevent. The pesticide label is a legally binding document that is extensively reviewed by pesticide manufacturers and by EPA. Any pesticide label can easily be looked up using the EPA’s Pesticide Product Label Search. It is meant to be followed exactly, and it should be clear and easy to understand for the typical applicator or user. This approach is referred to as “the label is the law.” As an example, we recommend readers examine the specimen label (Specimen Label Tempo^® 2) for a cyfluthrin insecticide called “Tempo^® 2,” manufactured by Bayer Corporation. Each product label states “(i)t is a violation of Federal law to use this product in a manner inconsistent with its labeling.” The EPA sets limits, called tolerances or maximum residue limits, for pesticide residues allowed in and on food after harvest. When setting the tolerance, EPA must determine that the pesticide can be used with “reasonable certainty of no harm” considering the toxicity of the pesticide and its metabolites, the amount and frequency of pesticide application, and the residues that will remain on the food after harvest, as determined in Setting Tolerances for Pesticide Residues in Foods. This tolerance level, if exceeded through monitoring, triggers enforcement and seizure of the food commodity by the government. In accordance with the FDA’s Inspections, Compliance, Enforcement, and Criminal Investigations, the FDA samples and monitors imported and domestic foods to ensure that pesticide residues are within established tolerances. All regulatory actions and processes, all scientific reviews of pesticide chemicals, and every related docket is available from EPA’s Pesticide Chemical Search. In the United Kingdom, a Pesticide Residues in Food committee monitors pesticide levels in food products. State enforcement agencies also check pesticide residue levels in domestic foods, and the United States Department of Agriculture (USDA) monitors residue levels in meat and milk, established in Setting Tolerances for Pesticide Residues in Foods. Before these tolerances are set, the public may comment on proposed pesticide tolerances in the Federal Register. After reviewing the comments and any additional data submitted, EPA decides whether to grant the tolerance or not. These decisions are also published in the Federal Register. All pesticide tolerances are published in the Code of Federal Regulations (CFR), Chapter 40, Part 180, which is revised annually in July.

• Pesticide Residues in Food UK Health and Safety Executive, Defra Expert Committee on Pesticide Residues in Food.

  In England, an expert committee monitors pesticide levels in produce, and the results are posted on this website.

• Schierow, L.-J., and R. Esworthy. Pesticide Law: A Summary of the Statutes, Congressional Research Service, 14 November 2012.

  This report clearly summarizes the major statutory authorities governing pesticide regulation: the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and Section 408 of the Federal Food, Drug, and Cosmetic Act (FFDCA), as well as the major regulatory programs for pesticide chemicals.

• Specimen Label Tempo^® 2. Bayer Corporation, 9 December 1996.

  This product label demonstrates the concept “the label is the law,” by informing both consumers and pesticide applicators what must be done to be in compliance. Furthermore, the label tells everyone what to look for if one suspects health problems or adverse environmental impacts from the use (or a spill) of this product.

• US Department of Agriculture. National Institute of Food and Agriculture.

  This site addresses safe use of pesticides by identifying alternative pest management methods and assessing the benefits and risks associated with pesticide use through research and education.

• US Environmental Protection Agency. About Pesticides.

  Because the EPA is the source of most pesticide regulations, this is the essential gateway agency for environmental and public health information on pesticide chemicals and rules governing pesticide products.

• US Environmental Protection Agency. Pesticide Product Label Search.

  One simply needs to enter the name of the pesticide product to get connected to the currently approved label from the Office of Pesticide Programs.

• US Environmental Protection Agency. Pesticide Chemical Search.

  This is “one-stop shop” for info on any pesticide product, with quick links for public involvement, product reregistration, tolerances, and label information.

• US Environmental Protection Agency. Pesticides and Food: How the Government Regulates Pesticides.

  This site provides information on how EPA and states, via authority from EPA, regulate pesticides in practice.

• US Environmental Protection Agency Setting Tolerances for Pesticide Residues in Foods.

  This is the best place to begin to understand how EPA sets tolerances and what the actual values are for common raw and processed foods.

• US Food and Drug Administration. Inspections, Compliance, Enforcement, and Criminal Investigations.

  This site provides specific information on the monitoring and compliance of pesticide levels on crops so that consumers can see what steps are taken to ensure a safe food supply.

• US National Library of Medicine. Toxicology and Environmental Health Information Program.

  This is a logical place to begin any analysis of pesticide information because the TEHIP hosts a comprehensive environmental health and toxicology web site that includes access to pesticide information produced by TEHIP and by other US government agencies.