Uptake and Metabolism of Dimethylamine Salt of 2,4-Dichlorophenoxyacetic Acid by Fish

Bluegills and channel catfish removed less than 0.5% of dimethylamine salt of ¹⁴C-ring-labeled 2,4- dichlorophenoxyacetic acid (DMA-[¹⁴C]-2,4-D) when exposed in aquaria to water containing 2 ppm of the herbicide. The maximum concentration of 2,4-D in the fish was reached within 24 h of treatment; thereafter it did not change significantly up to 7 days. Catfish removed a smaller amount of the herbicide from the water than bluegills. No evidence for bioaccumulation of 2,4-D in the fish was noted during the duration of the experiment. A major portion of the radioactivity absorbed by the fish was associated with the head and viscera portions with relatively low concentrations in the edible flesh. The fish did not metabolize 2,4-D during the 7 days following treatment. Bluegills administered DMA-[¹⁴C]-2,4-D by intraperitoneal injection excreted 90% of the herbicide within 6 h of treatment.