Polychlorinated dibenzo-p-dioxins and dibenzofurans in water and six fish species from Dongting Lake, China

Abstract

There have been few studies of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in environmental water because of the large volume of water required for PCDD/Fs analysis. Water quality directly affects aquatic organisms, and little is known about how PCDD/Fs are transported in aquatic environments. PCDD/Fs were analyzed in eight water samples from Dongting Lake, China, which was contaminated with PCDD/Fs because of sodium pentachlorophenate use between the 1960s and the 1980s. The total PCDD/F concentrations in the samples were 36–345pgL−1, and the mean was 191pgL−1. Octachlorodibenzo-p-dioxin was the most abundant PCDD/F congener in every sample, contributing 67–95% of the total 2,3,7,8-chlorinated PCDD/F concentrations. The toxic equivalent (WHO-TEQ) concentrations in the samples were 0.17–0.37pgL−1, and the mean was 0.28pgL−1, which is higher than the Canadian environmental quality guideline (0.038pgL−1 WHO-TEQ for freshwater) and the United States Environmental Protection Agency water quality criterion (0.014pgL−1 WHO-TEQ). PCDD/Fs were also determined in six fish species collected from Dongting Lake, to assess the concentrations, accumulation patterns, and potential for toxic effects. The total 2,3,7,8-chlorinated PCDD/F concentrations in the fish samples were 2.2–17.9pgg−1 (wet weight), and the dominant congeners were octachlorodibenzo-p-dioxin, 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin, 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin, and 2,3,4,7,8-pentachlorodibenzofuran. The PCDD/F WHO-TEQs were 0.10–0.92ww (3.3–65.3lw) pgg−1 in different species of fish. PCDD/F congener patterns in fish may be affected by food chain biomagnification and the lipid content of the species.