Research Product

A method for measuring fenthion in samples from the estuarine environment is described. The method was applied to samples from the field applications of fenthion to control salt-marsh mosquitos. The method offers an improvement in the silica gel cleanup of Thompson et al. and yields >85% recovery of fenthion from water, plant, fish, and shrimp tissues. Gas-liquid chromatography with thermionic detection was used to quantify fenthion residues as low as 0.010 µg/ l in seawater and 0.010 µg/g in biota. Concentration of fenthion residues ranged from undetectable to 0.68 µg/l in saltwater samples collected after truck-mounted ultra-low-volume or aerial spraying to control salt-marsh mosquitos.