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

Table 71. Total number of benthic crustaceans (tanaids, cumaceans, amphipods, copepods, and
ostracods; adapted from Tufts 1990).
Date Sampling
Control Plot
(change from pretreatment)
Treated Plot
(change from pretreatment)
June 30 Pretreatment 75 33
July 16 15 days post-treatment 96 (+28%) 2 (-94%)
August 01 30 days post-treatment 136(+181%) 4 (-82%)
December 10 161 days post-treatment 2 6
Field incidents reported in EPA incident database
NMFS reviewed reported incidents of fish deaths from field observations throughout the U.S.
because the information reflects real world scenarios of pesticide applications and corresponding
death of freshwater fish. We recognize that much of the information is not described in
sufficient detail to attribute an incident to a label-permitted use leading to the death of fish, or to
make conclusions regarding the frequency of fish kills that may be associated with the use of
pesticides. NMFS uses the information as a component to evaluate a line of evidence- whether
or not fish kills have been observed from labeled uses of the three pesticide products. EPA
categorizes incidents in the database into one of five levels of certainty: highly probable,
probable, possible, unlikely, or unrelated. The certainty level indicates the likelihood that a
particular pesticide caused the observed effects. EPA uses the following definitions to classify
fish kill incidents:
• Highly probable (4): Pesticide was confirmed as the cause through residue analysis or
other reliable evidence, or the circumstances of the incident along with knowledge of the
pesticides toxicity or history of previous incidents give strong support that this pesticide
was the cause.
• Probable (3): Circumstances of the incident and properties of the pesticide indicate that
this pesticide was the cause, but confirming evidence is lacking.
• Possible (2): The pesticide possibly could have caused the incident, but there are
possible explanations that are at least as plausible. Often used when organisms were
exposed to more than one pesticide.
• Unlikely (1): Evidence exists that a stressor other than exposure to this pesticide caused
the incident, but that evidence is not conclusive.
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