Requiring Clinical Diagnostic Tools and Biomonitoring of Exposures to Pesticides

Related Policies
APHA policy statement 2005-06: Reducing occupational exposure to benzene in workers and their offspring¹ 
APHA policy statement 2006-5: Addressing potential environmental and occupational health and safety risks of nanotechnology²
APHA policy statement 2002-5: Preserving right-to-know information and encouraging hazard reduction to reduce the risk of exposure to toxic substances³
APHA policy statement 2009-6: Elimination of Asbestos⁴ 
APHA policy statement 90-06: Occupational lead poisoning⁵
APHA policy statement 88-07: Surveillance of occupational disease and injury⁶ 
APHA policy statement 87-26: Toxic chemicals in agricultural products⁷ 
APHA policy statement 88-15: Emergency temporary standard for worker exposure to ethylene oxide⁸ 
APHA policy statement96-06: The precautionary principle and chemical exposure standards for the workplace⁹
APHA policy statement 2007-7: Calling on the US congress to restructure the Toxic Substances Control Act of 1976¹⁰ 
APHA policy statement 2000-11: The precautionary principle and children’s health¹¹ 
APHA policy statement 89-09: Reducing health risks related to environmental lead exposure¹²

The American Public Health Association (APHA) has a long history of supporting measures to improve worker protection from occupational exposure to toxic substances and surveillance of occupational injury and disease.^1–9 APHA also has established prior policy in the area of chemical safety for children and the general public.^10–12 This policy affirms the need to protect workers from occupational exposure to toxic substances; improve surveillance of occupational injury and disease; and provide stronger protection of farmworkers, their family members, and the general public from exposure to pesticides.

Pesticides are widely used tools in the production of the world’s food supply, in the protection of structures, in the prevention of illness transmission, and in the control of vector-borne diseases. As a group, however, pesticides contain some of the most toxic chemical products produced by modern chemistry. They are also unique among toxic environmental contaminants found in our environment; like no other chemicals except war gases, pesticides are purposefully released into our environment with the intention of doing harm to living beings. The World Health Organization (WHO) estimates that each year 3 million people are poisoned and 200,000 people die from pesticide exposure in the world; these figures reflect only a fraction of the real problem. Other estimates suggest that 25 million agricultural workers in developing countries suffer from pesticides poisonings each year.¹³

In the United States, the US Environmental Protection Agency (EPA) is responsible for the welfare of workers exposed to pesticides in the agricultural workplace, farmworker families, and the health of the public with respect to pesticides in food and the environment.^14–16 The EPA’s authority to oversee farmworker protection from pesticide exposure can be found in its regulatory authority under the Federal Insecticide Fungicide and Rodenticide Act of 1972 (FIFRA).¹⁴ FIFRA mandates that EPA, and not the Occupational Safety and Health Administration (OSHA), promulgate the regulatory standards to protect workers and their families from pesticide exposure.^14,17 Consequently, EPA and its designated state regulatory agencies oversee the worker protection standard (WPS), the primary regulatory standard that mandates workplace protection for hired agricultural laborers. The WPS involves pesticide safety training, notification of pesticide applications, use of personal protective equipment, restricted entry intervals after pesticide application, decontamination supplies, and emergency medical assistance.⁶ It is notably weaker than similar regulatory standards for occupations other than agriculture, and the WPS is poorly enforced.^18,19

Unlike OSHA, which in multiple standards requires that employers conduct medical monitoring of workers exposed to harmful substances,²⁰ EPA has no requirements for monitoring of workers exposed to pesticides. An essential component of the information that EPA uses to make decisions about the removal or restriction of use of a pesticide once on the market is information from surveillance systems.²¹ Several toxic pesticides have lost registration in the United States largely because of the information available to EPA through surveillance of pesticide poisonings. Examples include ethyl parathion and mevinphos.²² However, the ability of clinicians to report exposures through pesticide illness surveillance systems depends on their ability to diagnose pesticide poisonings. With the introduction to the marketplace of new pest-specific chemicals , diagnosis of human overexposure becomes even more difficult, because no human data on the health effects of these chemicals exist.²³ Cholinesterase activity, a marker of overexposure to organophosphate and carbamate pesticides, offers the only easily available confirmatory test for pesticide poisoning, and this marker is nonspecific. Washington and California require cholinesterase biomonitoring for pesticide applicators. These biomonitoring programs have been of substantial value in reducing overexposure by removing workers from ongoing exposure^24,25 and identifying flaws in the system of worker protection.²⁵

The Healthcare Information Portability and Accountability Act (HIPPA) and its penalties create barriers for release of protected health information by clinicians who might otherwise participate in surveillance systems. The clinician will no doubt resist reporting public health information unless diagnosis is certain and reporting is mandated. Although 30 states have rules requiring some form of clinician reporting of pesticide exposure and illness, only 11 states have a surveillance program to act on these reports.²⁶

In the United States, between 1 and 2.5 million hired farmworkers earn their living from agriculture.^23,27 Farmworkers are the working population most often affected by pesticide overexposure. In 1996, EPA estimated 10,000 to 20,000 occupational pesticide poisonings occurred among agricultural workers annually, based on extrapolation from California poisoning surveillance numbers.,28 More recent estimates are lower than that but are based on an inconsistent and incomplete surveillance system.²⁹ The majority of farmworkers are Latino; as a group, they are therefore disproportionately affected by pesticide exposures. Between 1998 and 2005, 3,281 cases of acute occupational pesticide poisonings among agricultural workers were identified through the National Institute for Occupational Safety and Health (NIOSH) supported Sentinel Event Notification System for Occupational Risks (SENSOR) Pesticides program and the

California Department of Pesticide Regulation. Of these cases, 727 (22%) had information on race or ethnicity. Of these 727 cases, 502 (69%) were Hispanic.²⁹

Farmworkers are a largely immigrant and marginalized population. They rarely have health insurance and have limited access to healthcare services. The support they receive from worker compensation claims, when state systems require the coverage of farmworkers, is essential to their ability to receive appropriate care. Accurate clinical diagnosis combines history, physical findings, and laboratory testing. In mild to moderate pesticide overexposures, a nonspecific clinical presentation is common. The availability of a diagnostic biomarker in these cases may confirm a clinical impression and may provide the objective confirmation of the work relatedness of an illness. Objective confirmation is essential to worker compensation determination.³⁰ In the absence of confirmatory tests to diagnose pesticide overexposure, farmworkers who suffer a pesticide-related illness are often denied the care they both deserve and have paid for through paycheck deduction to the workers’ compensation system.

Exposure assessment is consistently the weak link in the accuracy of results from environmental and occupational epidemiological studies.³¹ Biomarkers for exposure that could be applied in epidemiological studies would substantially improve our understanding of the health effects of pesticide exposure in both the short and long term.

The National Academy of Sciences proposed a new model for toxicity testing of chemicals that will limit the use of animals in testing and increase the use of structure activity modeling and cell-based toxicity testing systems. The new model emphasizes the critical importance of human population studies and population surveillance to validate the results of the models, provide information on host susceptibility, and help identify health risks not previously identified in toxicity testing. The ability to effectively develop useful population information will require biomarkers of exposure and confirmatory tests.³²

The US Government Accountability Office (GAO) recently produced two reports critical of EPA’s lack of use of biomarkers in estimates of health effects from commercial chemicals. Although these reports focused on chemicals covered by the Toxic Substances Control Act (TSCA) and did not address pesticides specifically, the GAO concluded that EPA should obtain legal authority from Congress to obtain and use biomonitoring data in regulating TSCA chemicals.³³

FIFRA gives EPA wide authority to require extensive information on potential health effects of pesticides from pesticide registrants. Based on this authority, EPA has a rigorous testing regimen that it mandates be completed for a company to register a pesticide. The regimen includes numerous toxicity tests on animals. It also includes metabolic fate studies and intense observation of experimental animals for subtle biological changes. EPA does not require that registrants provide either a biomarker or diagnostic tool to identify the negative health consequences of the use of its product.¹⁴

Recommendations Given: 

• The unique nature of pesticides as chemicals released into our shared environment to control or kill living creatures; 
• The importance of clinical diagnosis and exposure assessment to develop our understanding of the health effects of pesticides through surveillance and research; 
• The value demonstrated by the biomarker, cholinesterase, in surveillance efforts; 
• The essential nature of surveillance and biomonitoring in validating new models of toxicity testing; and 
• The regulatory strength of FIFRA that empowers the EPA to regulate. pesticides —

APHA recommends that EPA require pesticide registrants, as a requirement for registration, to develop and provide to the public —

• A sensitive and specific diagnostic test or biomonitoring tool to detect either chemical-specific levels in humans, the human health effects caused by their exposures, or both 
• A sensitive diagnostic test or biomonitoring tool to detect their chemical or its effects in human beings, the cost of which will be covered by the registrant

References

1. American Public Health Association. APHA policy statement 2005-06: Reducing occupational exposure to benzene in workers and their offspring. Washington, DC: American Public Health Association; 2005. Available at: http://www.apha.org/advocacy/policy/policysearch/default.htm?id=1322. Accessed June 12, 2010. 
2. American Public Health Association. APHA policy statement 2006-5: Addressing potential environmental and occupational health and safety risks of nanotechnology. Washington, DC: American Public Health Association; 2006. Available at: http://www.apha.org/advocacy/policy/policysearch/default.htm?id=1329. Accessed June 12, 2010. 
3. American Public Health Association. APHA policy statement 2002-5: Preserving right-to-know information and encouraging hazard reduction to reduce the risk of exposure to toxic substances. Washington, DC: American Public Health Association; 2002. Available at: http://www.apha.org/advocacy/policy/policysearch/default.htm?id=279. Accessed June 12, 2010. 
4. American Public Health Association. APHA policy statement 2009-6: Elimination of Asbestos. Washington, DC: American Public Health Association; 2009. Available at: http://www.apha.org/advocacy/policy/policysearch/default.htm?id=1380. Accessed June 12, 2010. 
5. American Public Health Association. APHA policy statement 90-06: Occupational lead poisoning. Washington, DC: American Public Health Association; 1990. Available at: http://www.apha.org/advocacy/policy/policysearch/default.htm?id=1217. Accessed June 12, 2010. 
6. American Public Health Association. APHA policy statement 88-07: Surveillance of occupational disease and injury. Washington, DC: American Public Health Association; 1988. Available at: http://www.apha.org/advocacy/policy/policysearch/default.htm?id=1169. Accessed June 12, 2010. 
7. American Public Health Association. APHA policy statement 87-26: Toxic chemicals in agricultural products. Washington, DC: American Public Health Association; 1987. Available at: http://www.apha.org/advocacy/policy/policysearch/default.htm?id=1155. Accessed June 12, 2010. 
8. American Public Health Association. APHA policy statement 88-15: Emergency temporary standard for worker exposure to ethylene oxide. Washington, DC: American Public Health Association; 1988. Available at: http://www.apha.org/advocacy/policy/policysearch/ default.htm?id=987. Accessed on June 12, 2010 ; 
9. American Public Health Association. APHA policy statement 96-06: The precautionary principle and chemical exposure standards for the workplace. Washington, DC: American Public Health Association; 1996. Available at: www.apha.org/advocacy/policy/policysearch/default.htm?id=124. Accessed June 12, 2010.
10. American Public Health Association. APHA policy statement 2007-7: Calling on the US congress to restructure the Toxic Substances Control Act of 1976. Washington, DC: American Public Health Association; 2007. Available at: http://www.apha.org/advocacy/policy/policysearch/default.htm?id=1350. Accessed June 12, 2010. 
11. American Public Health Association. APHA policy statement 2000-11: The precautionary principle and children’s health. Washington, DC: American Public Health Association; 2000. Available at: www.apha.org/advocacy/policy/policysearch/default.htm?id=216. Accessed June 12, 2010. 
12. American Public Health Association. APHA policy statement 89-09: Reducing health risks related to environmental lead exposure. Washington, DC: American Public Health Association; 1989. Available at: http://www.apha.org/advocacy/policy/policysearch/default.htm?id=1188. Accessed June 12, 2010.
13. Jeyaratnam J. Acute pesticide poisoning: a major global health problem. World Health Stat Q. 1990;43(3):139–144.
14. The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) of 1972; 7 USC §§136 et seq. (1972). Available at: http://www.epa.gov/oecaerth/civil/fifra/fifraenfstatreq.html and http://www.access.gpo.gov/nara/cfr/waisidx_01/40cfrv20_01.html. Accessed June 12, 2010.
15. Food Quality Protection Act of 1996 (FPQA). Pub L No. 104-170). Available at: http://www.epa.gov/opp00001/regulating/laws/fqpa/backgrnd.htm. Accessed June 12, 2010.
16. The Worker Protection Standard. 40 CFR §170. Available at: http://www.epa.gov/oppfead1/safety/workers/amendmnt.htm. Accessed June 12, 2010.
17. Organized Migrants in Community Action, Inc. v Brennan. 520 F.2d 1161 (1975).
18. Arcury TA, Quandt SA, Austin CK, et al. Implementation of EPA’s Worker Protection Standard training for agricultural laborers: an evaluation using North Carolina data. Public Health Rep. 1999;114(5):459–468.
19. US General Accounting Office. Pesticides: improvements needed to ensure the safety of farmworkers and their children. GAO/RCED-00-40. Washington, DC: US General Accounting Office; 2000. Available at: http://www.gao.gov/archive/2000/rc00040.pdf. Accessed March 31, 2010.
20. Silverstein M. Analysis of medical screening and surveillance in 21 Occupational Safety and Health Administration standards: support for a generic medical surveillance standard. Am J Ind Med. 1994;26(3):283–295.
21. Mevinphos. Proposed Amendment and Revocation of Tolerances. Federal Register. August 2, 1995;60(148). Available at: http://www.epa.gov/EPA-PEST/1995/August/Day-02/pr-357.html. Accessed June 14, 2010. 
22. Skeers V, Morrissey B. Acute organophosphate pesticide poisoning in Washington orchards. J Env Health. 1995;58(2):18–23.
23. Martin, P. Immigration Reform: Implications for Agriculture. Agricultural and Resource Economics Update. Davis, Calif: University of California, Giannini Foundation; 2006.
24. Ames RG, Brown SK, Mengle DC, et al. Cholinesterase activity depression among California agricultural pesticide applicators. Am J Ind Med. 1989;15(2):143–150.
25. Hofmann JN, Keifer MC, De Roos AJ, et al. Occupational determinants of serum cholinesterase inhibition among organophosphate-exposed agricultural pesticide handlers in Washington state. Occup Environ Med. 2010;67:375–386.
26. National Institute for Occupational Health and Safety. Pesticide-related illness and injury surveillance: a how-to guide for state-based programs. DHHS (NIOSH) Publication Number 2006-102. Washington, DC: National Institute for Occupational Health and Safety; 2005. Available at: http://www.cdc.gov/niosh/docs/2006-102/2006-102a.html. Accessed December 29. 2010.
27. Kandel W. Profile of Hired Farmworkers, a 2008 Update. Economic Research Report No. 60. Washington, DC: Economic Research Service, U.S. Department of Agriculture; 2008. 
28. Blondell, J. Epidemiology of pesticide poisonings in the United States, with special reference to occupational cases. Occup Med. 1997;12(2):209–220.
29. Calvert GM, Karnik J, Mehler L, et al. Acute pesticide poisoning among agricultural workers in the United status, 1998–2005. Am J Ind Med. 2008;51(12):883–898.
30. Attending Doctor’s Handbook. Olympia, Wash: Washington Department of Labor and Industries; 2005. Available at: http://www.lni.wa.gov/ipub/252-004-000.pdf. Accessed December 30, 2010.
31. Jurewicz J, Hanke W. Exposure to pesticides and childhood cancer risk: has there been any progress in epidemiological studies? Int J Occup Med Environ Health. 2006;19(3):152–169.
32. National Academy of Science. Toxicity Testing in the 21st Century: A Vision and a Strategy. Washington, DC: Committee on Toxicity Testing and Assessment of Environmental Agents, National Research Council; 2007.
33. US GAO. Biomonitoring: EPA Could Make Better Use of Biomonitoring Data. GAO-10-419T. Washington, DC: US Government Accountability Office; 2010.

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