Aquatic Organisms Laboratory Studies

The major degradation products of diflubenzuron in water are 4-chlorophenylurea and 2,6-difluorobenzoic acid these compounds are less toxic to aquatic organisms than the parent 

Diflubenzuron inhibits several enzyme systems in crab and insect larvae, resulting in disrupted glucose metabolism, reduced AGA incorporation into cuticle, and ultra-structural deformities of chitinous components of the cuticle. Specifically, diflubenzuron inhibits chitin synthetase, a magnesium-requiring enzyme that catalyzes the transfer of A-acetyl-D-glucosamine to chitin the final result is relatively large accumulations of AGAs. 

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Diflubenzuron effects on selected aquatic organisms laboratory studies... 

Table 17.4 Diflubenzuron Effects on Selected Aquatic Organisms Laboratory Studies...

The SPs have been shown to be highly toxic to fish and aquatic invertebrates, particularly arthropods, with toxicities as low as the nanogram per liter range in laboratory studies (see Sect. 3). However, due to their high lipophilicity and octanol water partition coefficient (Koc) values, they are rapidly adsorbed to suspended and bottom sediments [1], effectively limiting the exposure of water column organisms. 

The high BCF values observed for chlordecone (>60,000) indicate that the compound will be found in high concentrations in aquatic organisms that dwell in waters or sediments contaminated with chlordecone. Chlordecone has been detected in fish and shellfish from the James River, which empties into the Chesapeake Bay, at levels in the pg/g (ppm) range. There is currently a fish consumption advisory in effect for the lower 113 miles of the James River. Chlordecone residues were detected in foods analyzed from 1978-1982 and 1982-1986 as part of the Food and Drug Administration (FDA) Pesticide Residue Monitoring Studies. Chlordecone was detected in one of 27,065 food samples analyzed by 10 state laboratories, but was not detected in the more recent FDA Pesticide Residue Monitoring Studies from 1986 to 1991. No information on the specific foods in which residues were found or levels detected was located. 

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