Exposures of Aquatic Organisms to the Organophosphorus Insecticide, Chlorpyrifos Resulting from Use in the United States - Reviews of Environmental Contamination and Toxicology - page 85

2.3 Chlorpyrifos Marine Monitoring Data

Only the WA-EIM database (WDOE 2012 ) contained marine monitoring data.
No CPY was detected in any of the 42 samples of water collected after 2001, which
had method reporting limits of 0.002-0.0023 μg L −1 . No sediment samples were
analyzed.

2.4 Occurrence of Chlorpyrifos Oxon

Though not a listed USEPA contaminant (USEPA 2012), the NAWQA (NAWQA
2012 ), NASQAN (NASQAN 2012 ), CA-SWD (CDPR 2012a ), and WA-EIM
(WDOE 2012 ) databases also contained data on detections of CPYO and concentra-
tions that provide some insight into the possible earlier distribution of CPY. The
NAWQA database included results of 7,098 analyses for CPYO in surface waters
between 1999 and 2012. CPYO was detected in 16 samples, a rate of 0.23%. These
detections, however, were all estimated concentrations, which were less than the
LOQ, which ranged from 0.011 to 0.054 μg L −1 . The LODs were 0.007 to 0.34 μg L −1 .
In instances when CPY was sampled at the same time as CPYO was detected, con-
centrations of CPY were less than the MDLs of 0.005 to 0.006 μg L −1 in 75% of
samples (i.e., 9 of 12).
In the NASQAN database, CPYO was an analyte in 2,025 surface water sam-
ples collected between 2001 and 2012, and was detected in 9 samples-a detection
rate of 0.44%. Estimated concentrations (<LOQ) ranged from 0.011 to 0.036 μg L −1
and the detection limits were from 0.016 to 0.34 μg L −1 . In all cases when samples
were analyzed for CPY at the same time as CPYO (nine samples), concentrations
of CPY were less than the MDL of 0.005 to 0.006 μg L −1 . Neither the CA-SWD
(CDPR 2012a ) nor the EIM (WDOE 2012 ) databases contained any detections for
CPYO in surface waters. The CA-SWD included results of 288 analyses from 2005
to 2010 (LOQ = 0.05 to 0.06 μg L −1 ), while the EIM database contained results of
964 analyses (MDL = 0.048 to 0.1 μg L −1 ) from 2009 to 2011.

2.5 Exposures in Relation to Changes in Use-Pattern

Three different United States Geological Survey (USGS) studies used the same
pesticide concentration dataset (Martin and Eberle 2009 ) to examine trends in pes-
ticide concentrations in corn-belt streams (Sullivan et al. 2009 ), urban streams
(Ryberg et al. 2010 ), and streams of the western U.S. (Johnson et al. 2011 ). The
dataset containing concentrations of insecticides was compiled in the same manner
as the Martin et al. ( 2011 ) dataset, which included data only from 1992 to 2008.