Indirect sources of herbicide exposure for families on Ontario farms

Arbuckle, Tye E.; Bruce, Dana; Ritter, Len; Hall, J. Christopher

doi:10.1038/sj.jea.7500441

Cited by 20 publications

(16 citation statements)

References 21 publications

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“…The houses from a subsample of participants in the Agricultural Health Study in Iowa had 2,4-D detected in all house dust samples, and the concentration was associated with spray applications (Curwin et al 2005). The Ontario Farm Family Health Study also reported residual contamination of several household surfaces with 2,4-D (Arbuckle et al 2006). …”

Section: Discussionmentioning

confidence: 99%

Biomonitoring of 2,4-Dichlorophenoxyacetic Acid Exposure and Dose in Farm Families

Alexander

Mandel

Baker

et al. 2007

Environ Health Perspect

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ObjectiveWe estimated 2,4-dichlorophenoxyacetic acid (2,4-D) exposure and systemic dose in farm family members following an application of 2,4-D on their farm.MethodsFarm families were recruited from licensed applicators in Minnesota and South Carolina. Eligible family members collected all urine during five 24-hr intervals, 1 day before through 3 days after an application of 2,4-D. Exposure profiles were characterized with 24-hr urine 2,4-D concentrations, which then were related to potential predictors of exposure. Systemic dose was estimated using the urine collections from the application day through the third day after application.ResultsMedian urine 2,4-D concentrations at baseline and day after application were 2.1 and 73.1 μ g/L for applicators, below the limit of detection, and 1.2 μ g/L for spouses, and 1.5 and 2.9 μ g/L for children. The younger children (4–11 years of age) had higher median post-application concentrations than the older children (≥ 12 years of age) (6.5 vs. 1.9 μ g/L). The geometric mean systemic doses (micrograms per kilogram body weight) were 2.46 (applicators), 0.8 (spouses), 0.22 (all children), 0.32 (children 4–11 years of age), and 0.12 (children ≥ 12 years of age). Exposure to the spouses and children was primarily determined by direct contact with the application process and the number of acres treated. Multivariate models identified glove use, repairing equipment, and number of acres treated as predictors of exposure in the applicators.ConclusionsWe observed considerable heterogeneity of 2,4-D exposure among farm family members, primarily attributable to level of contact with the application process. Awareness of this variability and the actual magnitude of exposures are important for developing exposure and risk characterizations in 2,4-D–exposed agricultural populations.

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Section: Discussionmentioning

confidence: 99%

Biomonitoring of 2,4-Dichlorophenoxyacetic Acid Exposure and Dose in Farm Families

Alexander

Mandel

Baker

et al. 2007

Environ Health Perspect

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“…Blue = women 17 μ g/L (RfD), women 340 μ g/L (ToxCast reverse dosimetry). Red = child 21 μ g/L (RfD), child 450 μ g/L (ToxCast reverse dosimetry) see for review [218, 221]. …”

Section: Figurementioning

confidence: 99%

A Systematic Review of Carcinogenic Outcomes and Potential Mechanisms from Exposure to 2,4-D and MCPA in the Environment

Stackelberg

2013

Journal of Toxicology

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Chlorophenoxy compounds, particularly 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylphenoxy)acetic acid (MCPA), are amongst the most widely used herbicides in the United States for both agricultural and residential applications. Epidemiologic studies suggest that exposure to 2,4-D and MCPA may be associated with increased risk non-Hodgkins lymphoma (NHL), Hodgkin's disease (HD), leukemia, and soft-tissue sarcoma (STS). Toxicological studies in rodents show no evidence of carcinogenicity, and regulatory agencies worldwide consider chlorophenoxies as not likely to be carcinogenic or unclassifiable as to carcinogenicity. This systematic review assembles the available data to evaluate epidemiologic, toxicological, pharmacokinetic, exposure, and biomonitoring studies with respect to key cellular events noted in disease etiology and how those relate to hypothesized modes of action for these constituents to determine the plausibility of an association between exposure to environmentally relevant concentrations of 2,4-D and MCPA and lymphohematopoietic cancers. The combined evidence does not support a genotoxic mode of action. Although plausible hypotheses for other carcinogenic modes of action exist, a comparison of biomonitoring data to oral equivalent doses calculated from bioassay data shows that environmental exposures are not sufficient to support a causal relationship. Genetic polymorphisms exist that are known to increase the risk of developing NHL. The potential interaction between these polymorphisms and exposures to chlorophenoxy compounds, particularly in occupational settings, is largely unknown.

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“…Biomonitoring data for 2,4-dichlorophenoxyacetic acid (2,4-D) in urine samples are now available from a number of studies of both the general population (including preschool-age children) and farm applicators and their family members [Alexander BH, et al 2007; Arbuckle and Ritter 2005; Arbuckle et al 2002, 2004, 2006; Centers for Disease Control and Prevention (CDC) 2005; Morgan et al 2008]. Such data provide an integrated measure of absorbed dose from all pathways and routes of exposure.…”

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confidence: 99%

Biomonitoring Data for 2,4-Dichlorophenoxyacetic Acid in the United States and Canada: Interpretation in a Public Health Risk Assessment Context Using Biomonitoring Equivalents

Aylward¹,

Morgan

Arbuckle

et al. 2010

Environ Health Perspect

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BackgroundSeveral extensive studies of exposure to 2,4-dichlorophenoxyacetic acid (2,4-D) using urinary concentrations in samples from the general population, farm applicators, and farm family members are now available. Reference doses (RfDs) exist for 2,4-D, and Biomonitoring Equivalents (BEs; concentrations in urine or plasma that are consistent with those RfDs) for 2,4-D have recently been derived and published.ObjectiveWe reviewed the available biomonitoring data for 2,4-D from the United States and Canada and compared them with BE values to draw conclusions regarding the margin of safety for 2,4-D exposures within each population group.Data sourcesData on urinary 2,4-D excretion in general and target populations from recent published studies are tabulated and the derivation of BE values for 2,4-D summarized.Data synthesisThe biomonitoring data indicate margins of safety (ratio of BE value to biomarker concentration) of approximately 200 at the central tendency and 50 at the extremes in the general population. Median exposures for applicators and their family members during periods of use appear to be well within acute exposure guidance values.ConclusionsBiomonitoring data from these studies indicate that current exposures to 2,4-D are below applicable exposure guidance values. This review demonstrates the value of biomonitoring data in assessing population exposures in the context of existing risk assessments using the BE approach. Risk managers can use this approach to integrate the available biomonitoring data into an overall assessment of current risk management practices for 2,4-D.

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Indirect sources of herbicide exposure for families on Ontario farms

Cited by 20 publications

References 21 publications

Biomonitoring of 2,4-Dichlorophenoxyacetic Acid Exposure and Dose in Farm Families

Biomonitoring of 2,4-Dichlorophenoxyacetic Acid Exposure and Dose in Farm Families

A Systematic Review of Carcinogenic Outcomes and Potential Mechanisms from Exposure to 2,4-D and MCPA in the Environment

Biomonitoring Data for 2,4-Dichlorophenoxyacetic Acid in the United States and Canada: Interpretation in a Public Health Risk Assessment Context Using Biomonitoring Equivalents

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