Bibliography Tag: occupational exposure

Bibliography Index

Chester, 1993

Chester, G.; “Evaluation of agricultural worker exposure to, and absorption of, pesticides;” Annals of Occupational Hygeine, 1993, 37(5), 509-523; DOI: 10.1093/annhyg/37.5.509.

ABSTRACT:

The evaluation of the occupational exposure of agricultural workers to pesticides is an integral part of the risk assessment for product safety and regulatory purposes. At present, there is no internationally accepted, harmonized approach to this exposure evaluation. This paper reviews the currently available methods for the measurement of exposure to, and absorption of, pesticides by workers involved in their use and in associated agricultural activities. Biological monitoring is recommended as the most precise means of estimating the absorbed dose of a pesticide, particularly if supported by human metabolism and pharmacokinetic data. A ‘whole-body’ sampling method is recommended for the measurement of dermal exposure. For concurrent exposure and biological monitoring a refined ‘whole-body’ method is recommended which involves the use of clothing representing that which workers normally wear under the prevailing conditions. A personal air sampling method is recommended for the measurement of inhalation exposure, to collect the ‘inspirable’ fraction (and/or, where necessary, vapour component) of pesticide. These ambient exposure monitoring methods may be conducted simultaneously with biological monitoring. Guidelines are proposed for the conduct of field studies to evaluate exposure to, and absorption of, pesticides to satisfy the requirements of regulatory authority and other organization

Henderson et al., 1993

Henderson, P. T., Brouwer, D. H., Opdam, J. J., Stevenson, H., & Stouten, J. T.; “Risk assessment for worker exposure to agricultural pesticides: review of a workshop;” Annals of Occupational Hygeine, 1993, 37(5), 499-507; DOI: 10.1093/annhyg/37.5.499.

INTRODUCTION:

Pesticides are unusual among occupational chemical hazards, because they are designed to injure or to kill living organisms and are intrinsically toxic. Ideally they would be non-injurious to non-target organisms including man, but most are not highly selective. Therefore, their use should be regulated so that the health and safety of agricultural workers are assured. The key question is: “Are actual exposures safe?” The confidence with which this question can be answered depends on the knowledge of the toxicological properties of the pesticide followed by an assessment of the exposure that may be considered safe. Toxicological evaluation derives the ‘no observed-adverse-effect-levels’ (NOAEL) from experimental studies. The actual exposure must also be known. Comparing this with the NOAEL gives an insight to the risks experienced by the workers. There are several ways to estimate or assess exposure of the field worker. For the levels of exposure many factors are important, including physico-chemical properties of the pesticide, agricultural conditions, working procedure and environmental conditions. The central theme of the present Workshop was to achieve consensus about the optimum approach to:
—measurement of exposure of the agricultural worker, in which both ‘external’ and ‘internal’ exposure, in particular the role of biological monitoring, is considered;

—predictive exposure modelling;

—risk assessment and risk management of occupational exposure to pesticides.
Therefore four papers which follow this review were prepared. During the workshop, which was attended by 28 invited experts (see the List of Participants at the end of this review), the manuscripts were presented and each was critically reviewed by two or three invited respondents. This was followed by in-depth discussions. The present review summarizes the workshop discussions on the different subjects. The various recommendations and proposals that were presented, will be considered as starting points for deriving a harmonized approach to exposure and risk assessment.

 

Alavanja et al., 2004

Alavanja, M. C., Hoppin, J. A., & Kamel, F.; “Health effects of chronic pesticide exposure: cancer and neurotoxicity;” Annual review of public health, 2004, 25, 155-197; DOI: 10.1146/annurev.publhealth.25.101802.123020.

ABSTRACT:

Pesticides are widely used in agricultural and other settings, resulting in continuing human exposure. Epidemiologic studies indicate that, despite premarket animal testing, current exposures are associated with risks to human health. In this review, we describe the routes of pesticide exposures occurring today, and summarize and evaluate the epidemiologic studies of pesticide-related carcinogenicity and neurotoxicity in adults. Better understanding of the patterns of exposure, the underlying variability within the human population, and the links between the animal toxicology data and human health effects will improve the evaluation of the risks to human health posed by pesticides. Improving epidemiology studies and integrating this information with toxicology data will allow the human health risks of pesticide exposure to be more accurately judged by public health policy makers. FULL TEXT

Blair et al., 1985

Blair, A., Malker, H., Cantor, K. P., Burmeister, L., & Wiklund, K.; “Cancer among farmers. A review;” Scandinavian Journal of Work, Environment, & Health, 1985, 11(6), 397-407; DOI: 10.5271/sjweh.2208.

ABSTRACT:

During the performance of routine tasks farmers may come in contact with a variety of substances, including pesticides, solvents, oils and fuels, dusts, paints, welding fumes, zoonotic viruses, microbes, and fungi. Because some of these substances are known or suspected carcinogens, the epidemiologic literature regarding cancer risks concerning farmers has been reviewed. Farmers had consistent deficits for cancers of the colon, rectum, liver, and nose. The deficits for cancer of the lung and bladder were particularly striking, presumably due to less frequent use of tobacco among farmers than among people in many other occupational groups. Malignancies frequently showing excesses among farmers included Hodgkin’s disease, leukemia, non-Hodgkin’s lymphoma, multiple myeloma, and cancers of the lip, stomach, prostate, skin (nonmelanotic), brain, and connective tissues. The etiologic factors that may contribute to these excesses in the agricultural environment have not been identified. Detailed, analytic epidemiologic studies that incorporate environmental and biochemical monitoring are needed to clarify these associations. FULL TEXT

Blair and Zahm, 1993

Blair, A., & Zahm, S. H.; “Patterns of pesticide use among farmers: implications for epidemiologic research;” Epidemiology, 1993, 4(1), 55-62; DOI: 10.1097/00001648-199301000-00011.

ABSTRACT:

Epidemiologic studies of farmers have linked pesticides with certain cancers. Information on exposures from many of these studies was obtained by interview of farmers or their next-of-kin. The reliability and validity of data on pesticide use obtained by recall, often years after the event, have been questioned. Pesticide use, however, is an integral component in most agricultural operations, and the farmers’ knowledge and recall of chemicals used may be better than for many other occupations. Contrary to general belief, many farmers typically use only a few pesticides during their lifetimes and make only a few applications per year. Data from U.S. Department of Agriculture surveys indicate that herbicides are applied to wheat, corn, soybeans, and cotton and that application of insecticides to corn averages two or fewer times per year. In epidemiologic studies at the National Cancer Institute, the proportion of farmers ever reporting lifetime use of five or more different chemicals was 7% for insecticides and 20% for herbicides. Surrogate respondents have often been used in epidemiologic studies of cancer; they are able to recall pesticide use with less detail than the farmers themselves. The pesticides reported by surrogates were the same as reported by subjects themselves, but with less frequency. Comparison of reporting by cases and controls provided no evidence of case-response (differential) bias; thus, inaccurate recall of pesticide use by subjects or surrogates would tend to diminish risk estimates and dilute exposure-response gradients. FULL TEXT

Blair et al., 1992

Blair, A., Zahm, S. H., Pearce, N. E., Heineman, E. F., & Fraumeni, J. F., Jr.; “Clues to cancer etiology from studies of farmers;” Scandinavian Journal of Work, Environment, & Health, 1992, 18(4), 209-215; DOI: 10.5271/sjweh.1578.

ABSTRACT:

This article summarizes cancer risks among farmers to clarify the magnitude of the problem and to suggest directions for future research. Significant excesses occurred for Hodgkin’s disease, multiple myeloma, leukemia, skin melanomas, and cancers of the lip, stomach, and prostate. Nonsignificant increases in risk were also noted for non-Hodgkin’s lymphoma and cancers of connective tissue and brain. These excesses occurred against a background of substantial deficits among farmers for total mortality and mortality from many specific diseases. The tumors vary in frequency, histology, and prognosis and do not fall into any obvious grouping. Two commonalities may be important. Several of the tumors excessive among farmers appear to be rising in the general population and are excessive among patients with naturally occurring or medically induced immunodeficiencies. Therefore epidemiologic studies on specific exposures among farmers may help explain the rising trend of certain cancers in developed countries and provide clues to mechanisms of action for environmental carcinogens. FULL TEXT

 

Macfarlane et al., 2013

Macfarlane, E., Carey, R., Keegel, T., El-Zaemay, S., & Fritschi, L.; “Dermal exposure associated with occupational end use of pesticides and the role of protective measures;” Safety and Health at Work, 2013, 4(3), 136-141; DOI: 10.1016/j.shaw.2013.07.004.

ABSTRACT:

BACKGROUND: Occupational end users of pesticides may experience bodily absorption of the pesticide products they use, risking possible health effects. The purpose of this paper is to provide a guide for researchers, practitioners, and policy makers working in the field of agricultural health or other areas where occupational end use of pesticides and exposure issues are of interest.

METHODS: This paper characterizes the health effects of pesticide exposure, jobs associated with pesticide use, pesticide-related tasks, absorption of pesticides through the skin, and the use of personal protective equipment (PPE) for reducing exposure.

CONCLUSIONS: Although international and national efforts to reduce pesticide exposure through regulatory means should continue, it is difficult in the agricultural sector to implement engineering or system controls. It is clear that use of PPE does reduce dermal pesticide exposure but compliance among the majority of occupationally exposed pesticide end users appears to be poor. More research is needed on higher-order controls to reduce pesticide exposure and to understand the reasons for poor compliance with PPE and identify effective training methods.

FULL TEXT

Moore et al., 2014

Moore, C. A., Wilkinson, S. C., Blain, P. G., Dunn, M., Aust, G. A., & Williams, F. M.; “Percutaneous absorption and distribution of organophosphates (chlorpyrifos and dichlorvos) following dermal exposure and decontamination scenarios using in vitro human skin model;” Toxicology Letters, 2014, 229(1), 66-72; DOI: 10.1016/j.toxlet.2014.06.008.

ABSTRACT:

To date, there has been little research investigating low-level human exposure to chemicals, and so the aim of this study was to examine the percutaneous penetration of organophosphates (dichlorvos and chlorpyrifos) using low-level exposure scenarios in vitro. Dermal absorption of chlorpyrifos applied in different vehicles was measured at 0, 4, 8 and 24 h, after dose application for 4 and 24 h exposure (finite dose, 500 ng/cm(2)) in isopropanol (IPA), isopropyl myristate (IPM) and propylene glycol (PG). Dichlorvos was applied to the skin for 24 h (infinite dose, 1 mg/cm(2) and 10 mg/cm(2); finite dose, 5 mug/cm(2)) using the same vehicles. Human skin was mounted in flow through diffusion cells with minimum essential medium eagle pH 7.4 (supplemented with 2% BSA) as receptor fluid. Following exposure, the skin surface dose was removed by tissue swabbing, the stratum corneum removed by sequential tape stripping, and the skin digested prior to scintillation counting (chlorpyrifos), or GC/MS analysis (dichlorvos). The dermal absorption of chlorpyrifos was the greatest following application in PG (19.5% of dose), when compared with absorption from the IPA and IPM vehicles (10.3% and 1.9% absorbed respectively). However, dichlorvos showed greater dermal absorption than chlorpyrifos from all vehicles used, with greatest absorption from the IPA vehicle (38.6% absorbed). Although dichlorvos exhibited a short lag time (0.6 h from IPA and IP vehicles, and 0.4 h from PG), chlorpyrifos displayed greater propensity to accumulate in the stratum corneum and epidermis/dermis. These results demonstrate that prompt skin surface decontamination would be required for both dichlorvos and chlorpyrifos (and chemicals with similar properties) in the event of skin contact. The magnitude of the skin reservoir formed with chlorpyrifos was time dependent, therefore, prompt decontamination of this and similar chemicals would be required to reduce delayed systemic absorption.

Kezic and Nielsen, 2009

Kezic, S., & Nielsen, J. B.; “Absorption of chemicals through compromised skin;” International Archives of Occupational and Environmental Health, 2009, 82(6), 677-688; DOI: 10.1007/s00420-009-0405-x.

ABSTRACT:

Skin is an important route of entry for many chemicals in the work place. To assess systemic uptake of a chemical in contact with the skin, quantitative information on dermal absorption rates of chemicals is needed. Absorption rates are mainly obtained from studies performed with intact, healthy skin. At the work place, however, a compromised skin barrier, although not necessarily visible is common, e.g. due to physical and chemical damage. As reviewed in this article, there are several lines of evidence that reduced integrity of the skin barrier may increase dermal absorption of chemicals in the occupational setting. An impaired skin barrier might lead not only to enhanced absorption of a specific chemical, but also to entrance of larger molecules such as proteins and nanoparticles which normally are not able to penetrate intact skin. In addition to environmental influences, there is increasing evidence that some individuals have an intrinsically affected skin barrier which will facilitate entrance of chemicals into and through the skin making these persons more susceptible for local as well for systemic toxicity. This review addresses mechanisms of barrier alteration caused by the most common skin-damaging factors in the occupational settings and the consequences for dermal absorption of chemicals. Furthermore, this review emphasizes the importance of maintained barrier properties of the skin. FULL TEXT

Geer et al., 2004

Geer, L. A., Cardello, N., Dellarco, M. J., Leighton, T. J., Zendzian, R. P., Roberts, J. D., & Buckley, T. J.; “Comparative analysis of passive dosimetry and biomonitoring for assessing chlorpyrifos exposure in pesticide workers;” Annals of Occupational Hygeine, 2004, 48(8), 683-695; DOI: 10.1093/annhyg/meh056.

ABSTRACT:

Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), the US Environmental Protection Agency (EPA) has the authority to regulate the use of pesticides to prevent unreasonable adverse human health effects associated with pesticide exposure. Accordingly, the EPA requires pesticide registrants to perform studies evaluating the potential for pesticide handler exposure. Data from five such studies that included exposure measurements based on both external measurements and biological monitoring were used to examine methods of assessment, routes and determinants of exposure and dose to the pesticide chlorpyrifos. Eighty workers across four job classes were included: mixer/loaders (M/L, n = 24), mixer/loader/applicators (M/L/A, n = 37), applicators (A, n = 9) and re-entry scouts (RS, n = 10). Results showed that doses were highly variable and differed by job class (P < 0.05) with median total (inhalation and dermal combined) exposure-derived absorbed doses (EDADtot) of 129, 88, 85 and 45 microg/application for A, M/L/A, M/L and RS, respectively. Doses derived from the measurement of 3,5,6-trichloro- 2-pyridinol (3,5,6-TCP) in urine were similar in magnitude but differed in rank with median values of 275, 189, 122 and 97 microg/application for A, M/L, RS, and M/L/A, respectively. The relative contribution of dermal to inhalation exposure was examined by their ratio. The median ratios of exposure-derived absorbed dermal dose (EDADderm) (assuming 3% absorption) to exposure-derived absorbed inhalation dose (EDADinh) (assuming 100% absorption) across job classes were 1.7, 1.5, 0.44 and 0.18 for RS, M/L, A and M/L/A, respectively, with an overall median of 0.6. For 34 of 77 workers (44%), this ratio exceeded 1.0, indicating the significance of the dermal exposure pathway. Different dermal absorption factor (DAF) assumptions were examined by comparing EDADtot to the biomarker-derived absorbed dose (BDAD) as a ratio where EDADtot was calculated assuming a DAF of 1, 3 and 10%. Median ratios of 0.45, 0.71 and 1.28, respectively, were determined suggesting the DAF is within the range of 3-10%. A simple linear regression of urinary 3,5,6-TCP against EDADtot indicates a positive association explaining 29% of the variability in the 3,5,6-TCP derived estimate of dose. A multiple linear regression model including the variables EDADderm, EDADinh and application type explained 46% of the variability (R2 = 0.46) in the urinary dose estimate. EDADderm was marginally significant (P = 0.066) while EDADinh was not (P = 0.57). The EDADderm regression coefficient (0.0007) exceeded the coefficient for EDADinh (0.00002) by a factor of 35. This study demonstrates the value of the pesticide registrant database for the purpose of evaluating pesticide worker exposure. It highlights the significance of the dermal exposure pathway, and identifies the need for methods and research to close the gap between external and internal exposure measures. FULL TEXT

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