Abstract
Surface-water, groundwater, and suspended- and bedsediment
samples were collected in three targeted-use areas
in the United States where potatoes were grown during 2009
and analyzed for an extensive suite of fungicides and other
pesticides by gas chromatograph/mass spectrometry and liquid
chromatography with tandem mass spectrometry. Fungicides
were detected in all environmental matrices sampled during
the study. The most frequently detected fungicides were
azoxystrobin, boscalid, chlorothalonil, and pyraclostrobin.
Other pesticides that were detected frequently included
amino phosphonic acid (AMPA), atrazine, metolaclor, and
the organochlorine insecticide p,p’-DDT and its degradates
p,p’-DDD and p,p’-DDE.
A greater number of pesticides were detected in surface
water relative to the other environmental matrices sampled,
and at least one pesticide was detected in 62 of the 63 surfacewater
samples. The greatest numbers of pesticides and the
maximum observed concentrations for most pesticides were
measured in surface-water samples from Idaho. In eight surface-
water samples (six from Idaho and two from Wisconsin),
concentrations of bifenthrin, metolachlor, or malathion
exceeded U.S. Environmental Protection Agency freshwater
aquatic-life benchmarks for chronic toxicity to invertebrates.
Thirteen pesticides, including seven fungicides, were
detected in groundwater samples. Shallow groundwater
samples collected beneath recently harvested potato fields
contained more pesticides and had higher concentrations of
pesticides than samples collected from other groundwater
sources sampled during the study. Generally, pesticide concentrations
were lower in groundwater samples than in surfacewater
or sediment samples, with the exception of the fungicide
boscalid, which was found to have its highest concentration in
a shallow groundwater sample collected in Wisconsin.
Thirteen pesticides, including four fungicides, were
detected in suspended-sediment samples. The most frequently
detected compounds were the fungicides boscalid,
pyraclostrobin, and zoxamide, and the degradates p,p’-DDD
and p,p’-DDE. Twenty pesticides, including six fungicides,
were detected in bed-sediment samples. The most frequently
detected compounds were pyraclostrobin, p,p’-DDT,
p,p’-DDD, and p,p’-DDE.