The use of arsenicals to control aquatic vegetation has become widespread. A study was conducted to determine possible uptake of arsenic by fish in treated waters. Present methods for the analysis of arsenic (1,2) are reliable when applied to water and bottom samples which contain relatively small concentrations of organic matter. In the presence of larger concentrations, arsenic is lost during digestion. Recoveries of from 40-60 per cent were obtained when the method for the analysis of arsenic in food (2) was applied to fish flesh
