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

varigatus), an estuarine species, but the endpoint affected is described as reproduction and/or
growth, so whether or not growth was affected is uncertain. The Science Chapter (EPA 1998)
does not describe any data for estuarine/marine species.
Assessment endpoint: Habitat­ salmonid prey
Assessment measure: Aquatic invertebrate survival, growth, reproduction from acute and
chronic laboratory toxicity tests
The carbaryl BE (EPA 2003) lists a range of acute EC50 values for freshwater aquatic
invertebrate survival. Six EC50 values are given for Daphnia magna, ranging from 4.3 -13.0
μg/L (mean 7.3 μg/L). Although not specified as such, given the test organism, the fact that they
are noted as 48 h tests, and the range of percent a.i., we assume that these are guideline tests
conducted by the registrant or an acceptable government lab. EC50s were also given for three
species of stoneflies, ranging from 1.7-5.6 μg/L (mean 3.6 μg/L). An EC50 for an amphipod
(Gammarus fasciatus) of 26 μg/L was also given. There were also EC50 values for a number of
estuarine species. There were five EC50 values given for mysid shrimp (Mysidopsis bahia), a
common guideline test organism, ranging from 5.7-20.2 μg/L (mean 10.3 μg/L. EC50s for
various other shrimp species were given, ranging from 1.5-170 μg/L. All of these tests appear to
have been conducted on the a.i. An LC50 for blue crab of 320 μg/L was given. The BE also
reported a number of EC50/LC50 values for aquatic insects and other invertebrates derived from
the USEPA ECOTOX database.
The carbaryl Science Chapter (EPA 2003) used an acute value of 5.1 μg/L (stonefly, Chlorperla
grammatica) as the survival assessment endpoint for freshwater aquatic invertebrates, and
5.7 μg/L (mysid shrimp) as the survival assessment endpoint for estuarine/marine aquatic
invertebrates. The chapter also notes:
“Studies have indicated that acute exposure to carbaryl impacts
predator avoidance mechanisms in invertebrates, reduces overall
zooplankton abundance (Hanazato and Yasuno 1989; Havens
1995), and may actually promote phytoplankton growth through
reduced predation by zooplankton.”
Acute toxicity data for 1-napthol presented in the BE (EPA 2003) listed 48 h EC50s of 700-730
μg/L for D. magna, and EC50s of 200-210 μg/L for M. bahia. No additional information
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