Fluorescent whitening agents: Acute fish toxicity and accumulation studies

Abstract

Four fluorescent whitening agents (FWA), three of which are currently marketed in the United States for use as ingredients in household laundry detergents, were tested to determine their acute toxicity to the bluegill (Lepomis macrochirus), as well as their potential for significant accumulation in the flesh of the bluegill and channel catfish (Ictalurus punctatus), two species of fish common to U.S. waters. Results of the acute toxicity bioassays showed that no acutely toxic effects on fish, caused by these materials, would be expected at concentrations well above their projected environmental levels. Rates of accumulation and maximum levels accumulated were evaluated in the laboratory for a period of 90–105 days, followed by an examination of the rate of elimination of these materials from the fish over a 28-day period. Under these conditions, neither species accumulated any of three anionic fluorescent whitening agents (sulfonated stilbene derivatives) when exposed to nominal concentrations of 0.125, 1.25, or 12.5 μg 1−1 in water. A nonionic FWA not currently used in the U.S. detergent formulations was significantly accumulated at the two highest concentrations tested. The nonionic FWA accumulated was rapidly eliminated by fish upon their transfer to water devoid of this chemical. Elimination of FWA was essentially complete by 14 days. No significant accumulation by fish was detected with any FWA when exposure was conducted at levels approximating projected environmental concentrations. Details of the acute toxicity tests, and the patterns of accumulation and elimination seen in this study, as well as their significance, are discussed.