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

Under aerobic conditions, it degrades rapidly by microbial metabolism in soil and aquatic
environments. Metabolism is much slower in anaerobic environments, with half-lives on
the order of 2 to 3 months. Carbaryl is mobile in the environment. Sorption onto soils is
positively correlated with increasing soil organic content. Because of its low
octanol/water partition coefficient (Kow values range from 65 to 229), carbaryl is not
expected to significantly bioaccumulate (EPA 2003).
The major metabolite of carbaryl degradation by both abiotic and microbially mediated
processes is 1-naphthol. This degradate represented up to 67% of the applied carbaryl in
degradation studies. It is also formed in the environment by degradation of naphthalene
and other PAH compounds. Data suggest 1-naphthol “is less persistent and less mobile
than parent carbaryl (EPA 2003).
In a field dissipation study, carbaryl was applied on 3- to 8- ft tall pine trees in an
Oregon forest. Maximum measured concentrations were 264 mg/kg on foliage at 2 d
post-treatment, 28.7 mg/kg in leaf litter after 92 days, 0.16 mg/kg in the upper 15 cm of
litter-covered soil at 62 d, and 1.14 mg/kg in the upper 15 cm of exposed soil at 2 d.
Carbaryl was detected in the leaf litter up to 365 d after treatment and in litter-covered
soil up to 302 d after treatment. Half-lives were 21 d on foliage, 75 d in leaf litter, and 65
days in soil. Carbaryl was detected at