Chemical Exposure

Additional Chemical Exposure Publications

Hofmann J, Guardado J, Keifer M, Wesseling C. Mortality among a cohort of banana plantation workers in Costa Rica. Int J Occup Environ Health. 2006 Oct-Dec;12(4):321-8. PMID: 17168219.

Rodriguez T, Younglove L, Lu C, Funez A, Weppner S, Barr DB, Fenske RA. Biological monitoring of pesticide exposures among applicators and their children in Nicaragua. Int J Occup Environ Health. 2006 Oct-Dec;12(4):312-20. PMID: 17168218.

Lu C, Rodriguez T, Funez A, Irish RS, Fenske RA. The assessment of occupational exposure to diazinon in Nicaraguan plantation workers using saliva biomonitoring. Ann N Y Acad Sci. 2006 Sep;1076:355-65. PMID: 17119215.

McCauley LA, Anger WK, Keifer M, Langley R, Robson MG, Rohlman D. Free in PMC Studying health outcomes in farmworker populations exposed to pesticides. Environ Health Perspect. 2006 Jun;114(6):953-60. Review.PMID: 16760000.

Hines CJ, Deddens JA, Lu C, Fenske RA, Striley CA. Mixed-effect models for evaluating multiple measures of atrazine exposure among custom applicators. J Occup Environ Hyg. 2006 May; 3(5): 274-83. PMID: 16595379.

Lu C, Toepel K, Irish R, Fenske RA, Barr DB, Bravo R. Organic diets significantly lower children's dietary exposure to organophosphorus pesticides.Environ Health Perspect. 2006 Feb;114(2):260-3. PMID: 16451864.

Carden A, Yost MG, Fenske RA. Noninvasive method for the assessment of dermal uptake of pesticides using attenuated total reflectance infrared spectroscopy. Appl Spectrosc. 2005 Mar;59(3):293-9. PMID: 15901309.

Mancini F, Van Bruggen AH, Jiggins JL, Ambatipudi AC, Murphy H. Acute pesticide poisoning among female and male cotton growers in India. Int J Occup Environ Health. 005 Jul-Sep;11(3):221-32.

Tsai MY, Elgethun K, Ramaprasad J, Yost MG, Felsot AS, Hebert VR, Fenske RA. The Washington Aerial Spray Drift Study: Modeling Pesticide Spray Drift Deposition from an Aerial Application. Atmospheric Environment, 2005 39:6194-6203.

Wichanee S, Tianponkrang M, Jakiet M and Murphy H. Health hazards of pesticide use: studies by Thai school children. Section VI. Case studies. #17. in Children's Health and the Environment- A Global Perspective. Editor.  Pronczuk-Garbino J. WHO Press, Geneva Switzerland. 2005 pg. 332-335. Reprint available by request

Wu CF, Yost MG, Hashmonay RA, and Larson TV. Applying Open-Path FTIR with Computed Tomography to Evaluate Personal Exposures. Part 2: Experimental Studies Ann. 2005 Hyg., 49:73 - 83.

Wu CF, Yost MG, Hashmonay RA, and Larson TV and Guffey SE. Applying Open-Path FTIR with Computed Tomography to Evaluate Personal Exposures. Part 1: Simulation Studies Ann. Hyg., 2005 49:61 - 71.

Miranda J, McConnell R, Wesseling C, Cuadra R, Delgado E, Torres E, Keifer MC, and Lundberg I. Muscular strength and vibration thresholds during two years after acute poisoning with organophosphate insecticides. Occup Environ Med. 2004 January; 61(1): e4. PMCID: PMC1757809.

Ramaprasad J, Tsai MY, Elgethun K, Hebert VR, Felsot A, Yost MG, Fenske RA. The Washington Aerial Spray Drift Study: Assessment of Off-target Organophosphorus Insecticide Atmospheric Movement by Plant Surface Volatilization. Atmospheric Environment, 2004 38(33):5703-5713.

Curl CL, Fenske RA, Elgethun K. Organophosphorus pesticide exposure of urban and suburban pre-school children with organic and conventional diets. Environ Health Perspect. 2003;111:377-382

Fenske RA, Curl CL, Kissel JC. The effect of the 14-day agricultural restricted entry interval on azinphosmethyl exposures in a group of apple thinners in Washington State. Regulatory Toxicol Pharmacol. 2003;38:91-97.

Thompson B, Coronado GD, Grossman JE, Puschel K, Solomon CC, Islas I, Curl CL, Shirai JH, Kissel JC, Fenske RA. Pesticide take-home pathway among children of agricultural workers: study design, methods, and baseline findings. J Occup Environ Med. 2003;44(11):42-53.

Wu CF, Yost MG, Varr J, and Hashmonay RA. Applying Open-Path FTIR with a Bi-beam Strategy to Evaluate Personal Exposure in Indoor Environments: Experimental Results of a Validation Study. Am Ind. Hygiene Assoc. J., 64(2):181-188, 2003.

Beaudet N, Brodkin C, Stover B, Daroowalla F, Flack J, Doherty D. Crab allergen exposures aboard five crab-processing vessels. AIHA Journal. 2002;63:605-609.

Durand K, Muilenberg M, Burge H, Seixas N. Effect on sampling time on the culturability of airborne fungi and bacteria sampled by filtration. Ann Occ Hyg. 2002;46:113-118.

Fenske RA, Kedan G, Lu C, Fisker-Andersen JA, Curl CL. Assessment of organophosphorus pesticide exposures in the diets of preschool children in Washington State. J Exposure Analysis Environ Epidemiol. 2002;12:21-28.

Fenske RA, Birnbaum SG, Methner MM, Lu C, Nigg HN. Fluorescent tracer evaluation of chemical protective clothing during pesticide applications in central Florida citrus groves. J Ag Safety and Health. 2002;8(3):319-331.

Lu C, Knutson DE, Fisker-Anderson J, Fenske RA. Biological monitoring survey of organophosphorus pesticide exposure among pre-school children in the Seattle metropolitan area. Environ Health Perspect. 2001 Mar;109(3):299-303.

Miranda J, McConnell R, Lundberg I, Delgado E, Cuadra R, Keifer M, Wesseling C, Torres E. Cutaneous vibrotactile thresholds after acute intoxications with organophosphate insecticides. I J Occup Environ Health. 2002;8(3):212-219. Reprint Available by Request

Moate TF, Furia M, Curl C, Muniz  JF, Jyu J, Fenske RA. Size exclusion chromatographic cleanup for GCMS determination of organophosphorus pesticide residues in household and vehicle dust. J AOAC International. 2002;85:36.

Denovan LA, Lu C, Hines CJ, Fenske RA. Saliva biomonitoring of atrazine exposure among herbicide applicators. International Arch Occup Environ Health. 2000;73(7):457-462.

Doran EM, Yost MG, Fenske RA. Measuring dermal exposure to pesticide residues with attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy. Bull Environ Contam Toxicol. 2000;64(5):666-672. 

Kissel JC, Fenske RA. Improved estimation of dermal pesticide dose to agricultural workers upon reentry. Appl Occup Environ Hyg. 2000;15(3):1-7.

Lu C, Fenske RA, Simcox NJ, Kalman D. Pesticide exposure of children in an agricultural community: evidence of household proximity to farmland and take home exposure pathways. Environ Res. 2000;84:290-302.

Simcox NJ, Camp J, Kalman D, Stebbins A, Bellamy, Lee I, Fenske RA. Farmworker exposure to organophosphorus pesticide residues during apple thinning in central Washington State. Am Ind Hyg Assoc J. 1999;60:752-761.

Fenske RA, Schulter C, Lu C, Allen E. Incomplete removal of the pesticide captan from skin by standard handwash exposure assessment procedures. Bull Environ Contam Toxicol. 1998;61:194-201. Reprint Available by Request

Karr C, Keifer M, Miller M. Field-based monitoring of agricultural workers for overexposure to cholinesterase-inhibiting pesticides: evaluation of a trial program. J of Agromedicine. 1998;5(4)35-47.

Lu C, Fenske RA. Air and surface chlorpyrifos residues following residential broadcast and aerosol pesticide applications. Env Science Technol. 1998;32:1386-1390. Online Abstract

Fenske RA. Pesticide exposure assessment of worker and their families. Occupational Medicine State of the Art Reviews. 1997;12(2):221-237. Reprint Available by Request

Loewenherz C, Fenske RA, Simcox NJ, Bellamy G, Kalman D. Biological monitoring of organophosphorus pesticide exposure among children of agricultural workers in central Washington State. Environ Health Persp. 1997;105:1344-1353. PUBMED Abstract

Methner MM, Fenske RA. Pesticide exposure during greenhouse applications, Part III. Variable exposure due to ventilation conditions and spray pressure. Appl Occ Environ Hyg. 1996;11:174-180.

Simcox NJ, Fenske RA, Wolz S, Lee I-C, Kalman D. Pesticides in housedust and soil: exposure pathways for children of agricultural families. Environ Health Persp. 1995;103:1126-1134. EHP Abstract

McConnell R, Keifer M, Rosenstock L. Elevated quantitative vibrotactile threshold among workers previously poisoned with methamidophos and other organophosphate pesticides. Am J Industrial Med. 1994;25(3):325-335. PUBMED Abstract

Methner MM, Fenske RA. Pesticide exposure during greenhouse applications, Part I. Dermal exposure reduction due to directional ventilation and worker training. Appl Environ Occup Hyg. 1994;9:560-566. Reprint Available by Request

Methner MM, Fenske RA. Pesticide exposure during greenhouse applications, Part II. Chemical permeation through protective clothing in contact with treated foliage. Appl Environ Occup Hyg. 1994;9:567-574.    n/a

Children's Exposure to Lead and Arsenic in Orchard Soils (NIOSH/CDC, 1989-2002)

Lead arsenate was used in large quantities in orchards in Washington State for about four decades. Although lead arsenate is no longer used in the fruit industry, residual contamination is evident in orchard soils. Several potential routes of exposure to children exist. Adult workers in the orchards may inadvertently transport soil and dust to their homes or children residing in close proximity may play in the orchards. Orchard land may also be subdivided and converted to residential property. This project measured lead and arsenic levels in orchard and residential soil, house dust, and urinary biological specimens in children of farm workers employed in orchards formerly treated with lead arsenate.

Children's Pesticide Exposure (NIOSH/CDC, 1991-2002)

This investigation focused on the measurement of pesticide exposures in children of agricultural producers and farm workers and an analysis of risks associated with such exposures. It also explored new exposure assessment methods for evaluating exposure and risk in these populations. The project demonstrated that soil and house dust concentrations in and around the homes of agricultural families are significantly higher than those found for reference families in the same community, and that such patterns continue over several years. It has also been demonstrated that children of pesticide applicators had four times higher organophosphorus pesticide metabolite levels in urine as did reference children during the spraying season.

Publication List

Communication of Pesticide Health Risks Health Care Providers for Children of Agricultural Families (WA Sate MAAF, 2004-2007)

Through educational courses and workshops, we provided health care professionals with current scientific information regarding neurodevelopmental health risks for children with exposure to OP pesticides. This information was needed to understand the known, and sometimes uncertain, health risks to their pediatric patients. Based on our audience research, PNASH developed educational formats that meet health care professionals' need for current scientific information. For the web-based CME course, Organophosphate Pesticides and Child Health: A Primer for Health Care Providers, visit: http://depts.washington.edu/opchild/.

Communication of Pesticide Health Risks Producers, Workers and their Families (WA State MAAF, 2005-2007)

We provided the farming community with educational resources to promote the understanding of current science regarding the risks of OP pesticides. Our survey of producers and pesticide handlers in Washington state showed that respondents most often obtained their information on pesticides from product labels and dealers. They expressed interest in learning more about acute pesticide illness, cancer, ChE testing, and children’s health. The survey also showed the preferred route for received information to be from conferences, recertification classes, or articles. In addition, the Spanish speakers surveyed preferred to receive their information verbally at the job site or from a medical person.

Enhancements to Cholinesterase Monitoring: Oxime Reactivation and OP-ChE Adducts (NIOSH/CDC, 2006-2011)

Scientists at PNASH and the Centers for Disease Control (CDC) conducted this project to improve the current ChE laboratory test – increasing accuracy to ensure a ChE depression is due to pesticide exposure and identify the specific pesticide involved.

Organophosphorus pesticides (OPs) have widespread commercial application in the United States and worldwide, and their primary toxicological effect is associated with inhibition of cholinesterase (ChE). In Washington State, cholinesterase activity is measured in farmworkers expected to have high exposures to OPs, and when depression in cholinesterase activity is observed, remedial actions are undertaken to reduce exposures and protect worker health. However, the cholinesterase assay lacks sensitivity and specificity, with the result that a substantial number of false-positive and false-negative measurements are obtained. Misclassification of overexposure comes with substantial economic costs to local authorities and growers, and causes unnecessary psychological distress for the farmworkers. In the case of false-negative data, exposure misclassification fails to identify and correct situations where overexposure to pesticides has occurred.

To augment and improve cholinesterase monitoring, we developed and validated two analytical methods designed to measure the interaction of OP pesticides with cholinesterase enzyme. These assays were validated via a series of in vitro studies using human plasma, and in vivo studies in rats and in humans with occupational exposure to OP pesticides. Finally, the assays developed during this project were incorporated into the practice of OP pesticide exposure monitoring in Washington State.

Though not useful for clinical diagnosis, the oxime reactivation assay can be used to help diagnose acute poisoning with OP pesticides and guide treatment – for example, when a subject presents at an emergency clinic with symptoms consistent with pesticide poisoning. The second component of this project is the development of a process for tandem mass spectrometry (HPLC/MS/MS) of protein adducts in the blood of exposed workers. The HPLC/MS/MS method can detect exposures to OP pesticides at low levels more reliably than using the existing cholinesterase activity assays. These more sensitive adduct measurements can be combined with information about personal characteristics and workplace practices, either from surveys or intervention studies, to analyze risk factors associated with pesticide exposure. Results could be used to further educate workers and regulators regarding ways to minimize exposures.

 

Products

Farmworker OP Exposure through Protein Adducts (NIOSH/CDC 2011-2016, UW Royalty Research Fund 2012))

Organophosphorus (OP) pesticides cause illness through inhibition of cholinesterase, a critical enzyme in the nervous system. Our previous work developed an assay that provides greater sensitivity and specificity as compared to traditional cholinesterase monitoring – eliminating the need for collection of a baseline pre-exposure blood sample from each worker. We are expanding this assay to improve the understanding of worker exposures to a wide range of OP pesticides and developing it for use in field and clinic settings, providing rapid feedback to workers, clinicians, and physicians.

We have been very successful in developing the mass spectrometry based assays, and demonstrated the effectiveness of one of these in three populations with occupational exposure to OP pesticides. Further, we have begun to use these assays to identify risk factors associated with overexposure to OPs and susceptibility to the effects of OP exposure. Ultimately, utilization of these assays will help to ensure that workers are adequately protected against overexposure to OP pesticides and the associated adverse health outcomes.

FY2013 Accomplishments

  • Successfully developed immunoaffinitymagnetic bead (IMB) HPLC-MS/MS assay for sensitive determination of organophosphorus adducts to butyrylcholinesterase (BChE). A technique that simplifies sample preparation and reduces the amount of blood required.
  • Applied IMB HPLC-MS/MS assay to samples collected from pesticide handlers in Washington State. Compared performance of IMB HPLC-MS/MS assay to procainamide-gel purification of OP-BChE adducts, and to measurements of (plasma) cholinesterase depression. This comparison demonstrated that the faster and simpler IMB methods could be used in the place of the original method without compromising sensitivity.
  • Measured OP-BChE adducts and BChE activity in samples from cotton farmers and pesticide manufacturers in Pakistan. Analysis of this population of workers showed the adduct method to have good correlation with cholinesterase depression at high exposures as well as low. It also identified a group of workers who are at risk for pesticide poisoning.
Introducing a Cholinesterase Test Kit into Clinical Practice (NIOSH/CDC 2006-2011)

This project evaluated the feasibility and functionality of integrating a portable testing kit, the Test-mate ChE test system, into the existing state-wide cholinesterase monitoring program administered by Washington State OSHA (known as WISHA). The aim was to enhance and simplify worker monitoring of pesticide overexposure for certain agricultural workers. We have shown the Test-mate™ kit to be an effective, cost-efficient test that can provide rapid results for workers – important if they are shown to have a ChE depression. Mixed results were obtained from these studies. We showed it is feasible to use the test kit in place of the present commercial lab for measuring plasma ChE depression amongst pesticide handlers, but not for measurements of RBC ChE depression.

Due to the poor agreement between test-kit and State Lab data for RBC ChE, at this time we do not recommend using the test-kit to replace the state designated laboratory for RBC ChE testing. A reactivation procedure using the oxime 2-PAM was also developed and incorporated into the test kit. This procedure can provide additional evidence that a ChE depression resulted from exposure to OP pesticides, provided that blood samples are collected and analyzed within ~24 hours of exposure to pesticide. For the cohort of workers examined in the current study, too much time had elapsed between pesticide exposure and collection of blood samples and the oxime was unable to reactivate ChE activity in these samples. However, the oxime reactivation procedure would be useful for clinical diagnosis of acute poisoning with organophosphorus pesticides, and to guide patient treatment in such cases. The study provided guidance for medical clinics to evaluate clinic-specific issues that interfere with using the test kit. For example, significant barriers include: required certification, training costs, and physical space needed.

Pesticide Exposure Pathways in Agricultural Communities (EPA/NIEHS, 2004-2014)




Children of agricultural producers and workers can be exposed to pesticides and other agricultural chemicals if workplace chemicals are inadvertently brought into their homes. The purpose of this research is to prevent or reduce take home pesticide exposure among agricultural workers and their families in Northwest farming communities. This project will result in new methods for the characterization of the take home exposure pathway, and for interventions to reduce children’s exposures to pesticides.

Publication List

Pilot Project: Farm Exposures to Deposited Arsenic and Lead on Vashon Island (PNASH Pilot 1999-2000)

Vashon Island, Washington, is situated north of the former ASARCO smelter in Ruston/Tacoma. Prevailing winds carried arsenic and lead from the smelter to the Island. Surface soils are contaminated at levels well above background for both elements. Persons living on the island are subject to potentially elevated exposures to arsenic and lead. Persons at highest risk of exposure are likely to be those who have relatively intimate contact with soil. Those who eat locally grown crops are also at risk. Island farmers and their children are obvious targets for exposure assessment. A stakeholder group, the Vashon Island Growers’ Association, requested testing of farms and farmers for evidence of smelter residue contamination. During this project we collaborated with the community to investigate an at risk population and answered some of their questions.

Pilot Project: Human Exposure to OP Pesticides: The Role of Oxidative Stress (PNASH Pilot 2000-2001)

Compelling evidence from whole-animal and tissue culture studies indicate that pesticides, especially organophosphate pesticides (OP), induce oxidative stress. While the cholinergic properties of OPs are well-established, our understanding of their oxidative stress properties (especially on humans) is limited. Given the importance of oxidative stress in disease and the widespread use of pesticides, this project studied the relationship between OP pesticides and stress in humans by analyzing oxidative stress biomarkers in urine and lymphocytes of pesticide mixer/applicators. Work histories and information on current work practices was obtained. Dialkylphosphate metabolites, and work histories were used to estimate the internal dose and the levels of exposure. The project focused on the problem of chemical exposure in the agricultural work environment and how biomarkers can be used to assess the possible health hazards associated with chronic exposure to agrochemicals.

Pilot Project: Inhibition of Cholinesterase by Pharmacological and Dietary Agents (NIOSH/CDC 2007-2009)

Organo-phosphorus pesticides (OPs) have widespread commercial application in the United States and worldwide, and their primary toxicological effect is associated with inhibition of cholinesterase (ChE). In Washington State, cholinesterase activity is measured in farmworkers expected to have high exposures to OPs, and when depression in cholinesterase activity is observed, remedial actions are undertaken to reduce exposures and protect worker health. However, the cholinesterase assay lacks specificity: there are a number of dietary and pharmacological agents that can depress cholinesterase levels. In the context of the Washington State cholinesterase monitoring rule, this would lead to an incorrect conclusion that the worker had been overexposed to pesticide. This misclassification of exposure confounds epidemiological studies of farmworker health and pesticide exposure, and undermines worker and employer confidence in the cholinesterase monitoring program.

This pilot study measured the effect of quinine and acetaminophen on cholinesterase levels in vivo in humans. Quinine is a known inhibitor of cholinesterase, and the potential for exposure to quinine is high due to its presence as an ingredient in tonic water. Quinine and its analogs are also used medicinally as prophylaxis for malaria and muscle cramping. Acetaminophen (brand names: tylenol, paracetamol) is a common over the counter and prescription medication for pain relief and fever reduction. Acetaminophen is a known hepatotoxin, and has been shown to reduce cholinesterase levels in vitro. Both compounds have been suggested as potential confounders to the use of cholinesterase measurements as a marker for pesticide exposure.

Human volunteers ingested either quinine (singe acute dose) or acetaminophen (3g/day for up to 6 days), and the effect on plasma cholinesterase and acetylcholinesterase was monitored.

Pilot Project: Investigation of the Apparent Discrepancy Between Observed Cholinesterase Depression among Pesticide Handlers in Washington and Regulatory Estimates of Exposure (NIOSH/CDC, 2008-2010)

This small project predicted expected ChE depression based on regulatory decision-making frameworks and compares those predictions with actual outcomes in Washington State’s ChE monitoring program. Scientists at PNASH and the Centers for Disease Control (CDC) are working to improve the current ChE laboratory test – increasing accuracy to ensure a ChE depression is due to pesticide exposure and identify the specific pesticide involved. Though some challenges exist, the oxime reactivation assay has been successfully applied to human and rat plasma samples providing kinetic information regarding ChE inhibition and reactivation. The second component of this project was the development of a process for tandem mass spectrometry of protein adducts in the blood of exposed workers. Once perfected, this would be the only effective tool for determining long term exposures as the protein adducts last much longer than the actual pesticides or urinary metabolites.

Pilot Project: Oxygen Analogs and Worker Exposure During and Following Agricultural Spraying (NIOSH/CDC Pilot, 2009-2010)

The goal of this project was to characterize chlorpyrifos-oxon generation during pesticide applications in agricultural settings and the extent to which oxon generation is an artifact of sampling.

Pilot Project: Salivary Biomonitoring for Organophosphorus Pesticide Exposure in Children (PNASH Pilot, 1999-2000)

This project was designed to investigate the feasibility of measuring pesticide exposure using saliva in children. Conventional biomonitoring methods, such as blood and urine collections, have several, inherent practical limitations, which prohibit its application to large-scale studies or to studies involving sub-populations, such as children.  Saliva biomonitoring could provide a useful tool for researchers in determining not only the exposure to certain chemicals, such as pesticides, but the absorbed dose as well. A cohort of children who live in an agricultural community has been identified and recruited for this feasibility study. Saliva samples have been collected before and after the application of pesticides to fields close to their homes, and will be analyzed for pesticide residues.

Risk Factors for Cholinesterase Depression among Pesticide Handlers (NIOSH/CDC, 2006-2011)

This project worked in coordination with the Washington State Cholinesterase (ChE) Monitoring Program to identify the risk factors responsible for ChE depressions, including individual genetic susceptibility. 245 handlers were recruited over the course of this study in collaboration with occupational medicine clinics in agricultural regions of Washington state. A participant's risk of ChE depression is evaluated with respect to workplace, behavioral, and genetic characteristics (paraoxonase or PON1 status). Findings identified the following risk factors being associated with BuChE inhibition: cleaning spray equipment, mixing/loading pesticides and not using a locker to store PPE. Protective factors were: wearing a full-face respirator and wearing chemical-resistant footwear. Identification of genetic susceptibility (PON1 status) in farm workers exposed to organophosphate pesticides. This is the first time that a study of a working population has demonstrated the validity of the assumptions behind PON1’s effect on pesticide overexposure susceptibility.

Public Materials & Presentations:

Cholinesterase Inhibition Buena Salud La Inhibicion del Colinesteraza
Good Fruit Grower, March 2009

Risk Factors for Pesticide Exposure
Agricultural Safety Day, Yakima, WA February 20, 2008 English Session

Publication List:

Hofmann JN, Checkoway H, Borges O, Servin F, Fenske RA, KEifer MC. Development of a Computer-Based Survey Instrument for Organophosphate and N-Methyl-Carbamate Exposure Assessment among Agricultural Pesticide Handlers. Annuals of Occupational Hygiene 2010: April 22.

Hofmann JN, Keifer MC, Checkoway H, De Roos AJ, Farin FM, Fenske RA, Richter RJ, van Belle G, Furlong CE. Biomarkers of Sensitivity and Exposure in Washington State Pesticide Handlers. Advances in Exposure Medical Biology 2010:660:19-27

Hofmann JN, Keifer MC, Furlong CE, De Roos AJ, Farin FM, Fenske RA, van Belle G, Checkoway H. Serum cholinesterase inhibition in relation to paraoxonase (PON1) status among organophosphate-exposed agricultural pesticide handlers. Environmental Health Perspectives 2009 Sp;117(9):1402-08.

Hofmann JN, Keifer MC, De Roos AJ, Fenske RA, Furlong CE, van Belle G, Checkoway H. Occupational determinants of serum cholinesterase inhibition among organophosphate-exposed agricultural pesticide handlers in Washington State. Occupational and Environmental Medicine 2009.

Workplace Determinants of Take-Home Pesticide Exposure (NIOSH/CDC, 2001-2006)

This series of field-based studies has confirmed that agricultural pesticides are moving from the workplace to workers’ homes and that commuter vehicles play a role in this transmission. A major finding of the intervention development and evaluation is that vacuuming personal vehicles significantly reduces pesticide residues found in workers’ homes. PNASH will be widely promoting the practice of vehicle vacuuming and will be continuing to develop practical and effective workplace interventions designed to interrupt the take-home pathway.