Carbaryl, Carbofuran, and Methomyl - National Marine Fisheries ...

citation. We located the data report and confirmed that embryo hatchability was not affected by
the dose regime tested: 0, 57, 113, 254, 395, and 972 μg/L (measured concentrations).
Assessment endpoint: Fish growth
Assessment Measure: Growth rate, weight, length, or biomass of second generation as
measured in chronic toxicity tests
The carbaryl BE (EPA 2003) did not report any effects on growth for either freshwater or
estuarine/marine species, although reduced growth is listed as the affected endpoint in a fathead
minnow (Pimephales promelas) study referenced in the Science Chapter (EPA 2003). For this
study, the NOAEC is given as 210 μg/L and the LOAEC as 680 μg/L However, the fathead
minnow study discussed within the reproductive endpoints summary measured growth of fathead
minnow larvae (length) at 30 and 60 days (Carlson 1971). Although statistical tests were not
used, no differences in growth were apparent between exposed and control fish at the
concentrations tested: 8, 17, 62, 210, and 680 μg/L (Carlson 1971).
The carbofuran BE (EPA 2004) reports larval rainbow trout (O. mykiss) exposed to 56.7 and 88.7
μg/L carbofuran had significantly reduced lengths and reduced survival at 60, 75, and 90 d
compared to unexposed trout in a partial life cycle test. Additionally, trout weight was
significantly reduced after 75 d of exposure to 56.7 and 88.7 μg/L. Although, no definitive
reference was provided for these data, NMFS obtained the study report to verify study results.
Upon review, several additional adverse effects to fry were noted throughout the experiment. At
day 20, trout exposed to 57.8 and 88.7 μg/L respired rapidly compared to control fish and were
hyperactive at 88.7 μg/L. These effects continued for the remainder of the experiment (~ 70
days). Following 75 d of exposure to carbofuran at 56.7 and 88.7 μg/L, 23 and 35% of the fish,
respectively, had curved spines. The Science Chapter (EPA 2005) reports growth was the most
sensitive endpoint in two sheepshed minnow studies (Cyprinodon varigatus, MRIDs 40818401
and 42697401), but notes that neither of these tests produced a definitive NOAEC or LOAEC.
The methomyl BE (EPA 2003) lists a NOAEC of 76 μg/L and a LOAEC of 142 μg/L based on
growth endpoints for fathead minnow (Pimephales promelas), a freshwater species. It also lists a
NOAEC of 260 μg/L and a LOAEC of 490 μg/L for sheepshead minnow (Cyprinodon
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