Persistence of 2,6-Dichlorobenzonitrile in aquatic environments

In two experiments 2,6-dichlorobenzonitrile was added to aquatic systems, and the residue levels were followed for about 6 months. A granular formulation applied to a farm pond at 0.6 p.p.m. produced highest residues in water and fish about 2 weeks following treatment whereas vegetation and soil samples had the highest levels within 1 or 2 days. Residues were still measurable after 188 days. In ponds treated with a wettable powder formulation at 10, 20, and 40 p.p.m., residues in water and fish were highest within 3 days after treatment. The concentration in water 11 days after treatment was about 2% of the three-day level. Fish whole-body residues dropped nearly as fast but were still measurable at 112 days.