Heavy metals exposures among Mexican farmworkers in eastern North Carolina.
BACKGROUND
Immigrant farmworkers are a population at risk for numerous environmental and occupational exposures. The metals arsenic, lead, mercury, and cadmium are known neurotoxins to which workers can be exposed both in the US and in their country of origin. Because farmworkers are exposed to neurotoxic pesticides, they may be at risk for adverse health effects from the combined exposure.


OBJECTIVE
To examine the relationship between exposure to metals, as measured in urine, with personal and work-related characteristics of Mexican migrant and seasonal farmworkers in the US.


METHODS
We analyzed data on metals found in urine of 258 farmworkers recruited from 44 camps in eastern North Carolina in 2007. Geometric means and 95% confidence intervals (CI) were used to compare data with data from the National Health and Nutrition Examination Survey (NHANES). We used multivariate regression models fitted for each metal to estimate the association of creatinine-corrected urinary metals and worker characteristics related to environmental and occupational exposures.


RESULTS
Geometric mean urinary metals concentrations (mug/g creatinine) exceeded NHANES reference values for arsenic (13.23 [CI 11.11, 15.35] vs. 8.55 [CI 7.23, 9.86]) and lead (1.26 [CI 1.08, 1.43] vs. 0.63 [CI 0.60, 0.66]). Age, being from the central region of Mexico, and pack years of cigarette smoking were significant predictors of metals exposure; being a current smoker and years worked in US agriculture were not.


CONCLUSIONS
This first study to examine indicators of worker body burdens of metals shows that workers have body burdens related to exposures other than work in the US. Further research should address their risk for adverse health outcomes due to combined exposures to neurotoxins in pesticides.
Quandt
Sara A
SA
Department of Epidemiology and Prevention, Division of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA. squandt@wfubmc.edu
Jones
Bradley T
BT
Talton
Jennifer W
JW
Whalley
Lara E
LE
Galván
Leonardo
L
Vallejos
Quirina M
QM
Grzywacz
Joseph G
JG
Chen
Haiying
H
Pharr
Kathryn E
KE
Isom
Scott
S
Arcury
Thomas A
TA
D000293:Adolescent; D000328:Adult; D000383:Agriculture / Q000706:statistics & numerical data; D001822:Body Burden; D004785:Environmental Pollutants / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D019216:Metals, Heavy / Q000652:urine*; D008800:Mexico / Q000208:ethnology; D015999:Multivariate Analysis; D009657:North Carolina; D016273:Occupational Exposure / Q000032:analysis*; D012044:Regression Analysis; D011795:Surveys and Questionnaires; D055815:Young Adult
D004785:Environmental Pollutants; D019216:Metals, Heavy