Occurrence of Current-Use Pesticides in Paired Indoor Dust, Drinking Water, and Urine Samples from the United States: Risk Prioritization and Health Implications

Despite
being regarded as safer alternatives to legacy pesticides,
current-use pesticides (CUPs) are now identified as emerging contaminants
with growing evidence of their toxicity to wildlife and humans. In
this study, we collected matched samples of indoor dust, drinking
water, and urine from 81 households in Indiana, United States, and
analyzed these samples for 82 CUPs, including 48 insecticides, 25
herbicides, and 9 fungicides. Of these, 47 CUPs were identified across
samples of indoor dust, drinking water, and urine with median total
CUP (∑CUP) concentrations of 18 300 ng/g, 101 ng/L,
and 2.93 ng/mL, respectively. Notably, concentrations of neonicotinoids
(NEOs) in indoor dust were higher than those reported in other studies.
Herbicides were the most abundant CUPs detected in drinking water,
constituting 55% of the ∑CUP concentrations. Insecticides were
the most abundant CUP group detected in urine (median total insecticide
concentration: 2.30 ng/mL), followed by herbicides (median: 0.409
ng/mL) and fungicides (median: 0.0531 ng/mL). The highest estimated
daily intake (EDI) from drinking water and dust exposure was found
for imidacloprid, with a median value of 1.00 ng/kg of body weight/day.
Our results show that indoor dust is a significant exposure pathway
for most insecticides and fungicides, while herbicides are mainly
consumed through drinking water. In addition, the toxicity equivalent
factor model, incorporated with data retrieved from the ToxCast database,
indicated that imidacloprid poses the greatest health risk based on
its high exposure levels and toxicity. This study underscores the
importance of monitoring CUPs in indoor environments and sheds light
on their potential health risks.