Field application methods for recovery of the selective lampricide, 3-trifluoromethyl-4-nitrophenol

Colorimetric methods are described for the detection of residues of the selective lampricide, 3-trifluoromethyl-4-nitrophenol (TFM), in natural waters and fish tissues. Solvent extraction and anion exchange were used to separate and concentrate the lampricide, and to reduce high background colors which often interfere with the determinations. Data from the Pentwater and Muskegon Rivers (Michigan) showed an exponential rate of disappearance of TFM from the water immediately after treatments to eradicate larvae of the sea lamprey (Petromyzon marinus). No TFM was recovered from fish exposed in their natural environment to low levels of the lampricide during treatment; residues were recovered, however, from fish exposed to high concentrations in the laboratory.