Better than Eating Worms?
Children's Dietary Exposure to OP Pesticides
Widespread agricultural use of organophosphate (OP) pesticides
frequently leads to low-level exposures in adults and children who eat
conventionally grown foods. The frequently used one-time measurement of
OP metabolites reveals only short-term exposures, thereby providing
little evidence on long-term low-level exposures. A new article
presents longitudinal evidence that foods grown in conventional
fashion—that is, with the use of pesticides—may be a predominant source
of exposure in children
[
EHP 116:537–542; Lu et al.].
The article sprang from the Children's Pesticide Exposure Study,
which focused on two groups of children (3–11 years of age) in the
Seattle and Atlanta areas from July 2003 to May 2004. For the present
study, the researchers examined 23 children in Seattle (19 of whom
completed the study) who normally consumed conventional diets. Parents
tracked food consumption during the study and collected urine samples
twice daily.
During interventions over the course of the study, the children's
conventional diets were replaced with organic diets and the differences
in urinary metabolites of OP pesticides were measured. The organic
diets substituted conventionally produced grain, fruit, juice, and
vegetables with those produced without pesticides; meat and dairy
products rarely contain OP pesticides and were not substituted. During
the summer and fall 2003 intervention periods (15 and 12 days,
respectively), the children consumed their regular diets from days 1 to
3 and organic diets from days 4 to 8. After day 8, the children resumed
their regular diets. There was no organic diet intervention during the
winter and spring 2004 sampling periods.
Urine samples were analyzed for metabolites of malathion,
chlorpyrifos, diazinon, coumaphos, and methyl pirimiphos; only
chlorpyrifos and malathion metabolites were detected frequently enough
for statistical analysis. These metabolite levels fell to nearly or
fully nondetectable levels within days of the children beginning an
organic diet intervention and rose when the children returned to
conventional diets.
Given that OP pesticides were reported by parents not to have been
used in the home and that urinary metabolites were clearly affected by
diet, the researchers conclude that conventionally produced foods were
the primary source of OP pesticide exposure for the children in this
study. They also attribute higher dietary exposures to imported produce
eaten in the winter and spring when domestic produce is not available.
This finding is supported by a 2006 Environmental Protection Agency
report showing that OP residues on imported produce have risen since
1996 even as residues on domestically grown produce have fallen.
The authors caution, however, that their findings do not promote
limiting fresh produce or eating only organic items, as it is unknown
whether the observed exposures are harmful. Additionally, the study
group did not represent the general population. However, the findings
do provide a basis for more accurate assessment of exposure and
associated efforts to determine the effects of OP pesticides on
children's health.
Originally published on http://www.ehponline.org
