Risks to Aquatic Organisms from Use of Chlorpyrifos in the United States - Reviews of Environmental Contamination and Toxicology - page 126

Episodic exposures of aquatic organisms to CPY in fl owing waters were assessed
for several scenarios that were selected to represent typical situations (Williams
et al. 2014 ) and reasonable worst-case exposures, relative to times necessary for
arthropods and fi sh to recover during intervals between exposures. In addition,
responses and recoveries in microcosms were compared to modeled and measured
exposures.

3 Characterization of Effects

The toxicity of CPY to non-target organisms was extensively reviewed in 1995
(Barron and Woodburn 1995 ) and this review was used as an initial reference source.
Toxicity data from acute studies in aquatic organisms also were obtained from the
USEPA ECOTOX database (USEPA 2007 ), from studies conducted by Dow
AgroSciences, and from the open literature (SI Table 1 ).

3.1 Evaluation and Selection of Data

Studies were assessed for appropriateness by using criteria (Table 1 ) similar to those
recommended for assessing studies for inclusion in the International Uniform
Chemical Database (IUCLID) (Klimisch et al. 1997 ), except that numerical values
were assigned to the individual criteria. Scores used to characterize studies are
described below, and these were mostly used to assess data from the open literature.
Guideline studies conducted under Good Laboratory Practice (GLP) with full
Quality Assurance/Quality Control (QA/QC) were given the maximum score unless
they had <5 concentrations of exposures, the recommended number for guideline
studies such as those of OECD.
Applied experimental procedures were scored from 1 to 5 (Table 1 ). A score of
1 was assigned if the design was inadequately described or incorrect and a 5 if it was
complete, such as a guideline study conducted under GLP and with a clear protocol.
Examples of factors considered when judging study quality were: incomplete
description of the methods, inappropriate designs such as pseudoreplication and
lack of appropriate controls, lack of information about test organisms, replicates, or
number of test subjects per replicate, lack of an adequate description of the purity or
form of the test substance, inappropriate statistical comparisons, lack of details
about husbandry of organisms, lack of details on analytical methods, etc.
The use of QA/QC was scored from 1 to 5 (Table 1 ). If there was full QA/QC,
the score was 5. Scores of 2-4 were assigned based on the amount of QC, such as,
for example, measurements of exposure concentrations at the start of the study only
(score = 2) or measurements of exposures and other parameters at regular intervals
(score = 3).