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Polybrominated diphenyl ethers (PBDEs) levels in environmental media have increased over the last 20-25 years in the world. In aquatic environments PBDEs were found to be accumulated along food chain and Endocrine disruptors toxicity. In this study PBDEs were investigated in sediment and fish tissues from Lake Chaohu in central eastern China. There were 10 PBDEs congeners detected out of all 41 PBDEs. BDE-47 was of the highest with 5.17 ng/g in sediment and 58.47 ng/g in fish. PBDEs were evenly distributed across the surface sediment in the whole lake. It implied that the main source of PBDEs may not be an inflow river like Nanfei. Tissue distribution patterns of PBDEs in four fish species were in the order of BDE-47 > BDE-99 > BDE-100 > BDE-66 > BDE-138 > BDE-183 > BDE-154 > BDE-153. Octa- and deca-BDEs were below the detection limit. The concentrations of all PBDE congeners were higher in gills, livers, and kidneys than those in muscles and adipose tissue. Furthermore, PBDEs in different tissues had some different distribution patterns with fish size. Those discrepancies appeared to be correlated with the PBDEs pollution fluxes varying with the change of the year and their metabolism divergences in fish tissues.

Hexabromocyclododecane (HBCD) is a brominated flame retardant used throughout the world. It has been detected in various environmental media and has been shown toxic to aquatic life. The toxic effects of HBCD to aquatic organisms in Chinese freshwater ecosystems are discussed here. Experiments were conducted with nine types of acute toxicity testing and three types of chronic toxicity testing. After comparing a range of species sensitivity distribution models, the optimal model of Bull III was used to derive the safety thresholds for HBCD. The acute safety threshold and the chronic safety threshold of HBCD for Chinese freshwater organisms were found to be 2.32 mg/L and 0.128 mg/L, respectively. Both values were verified by the methods of the Netherlands and the United States. HBCD was found to be less toxic compared to other widely used brominated flame retardants. The present results provide valuable information for revision of the water quality standard of HBCD in China. [ABSTRACT FROM AUTHOR]

Abstract: Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are two widely used perfluorinated compounds. They have been detected in various environmental media and have harmed aquatic life and systems. The toxic effects of PFOS and PFOA on freshwater organisms were explored with the goal of protecting aquatic ecosystems in this study. Data from acute toxicity tests using nine aquatic species and chronic toxicity tests using three species were analyzed, along with PFOS and PFOA toxicity data for representative Chinese aquatic biota that have been published in the Chinese and international literature. Using the method recommended by the United States Environmental Protection Agency (US EPA), the criterion maximum concentration (CMC) for PFOS was calculated to be 3.78mg/L, and the criterion continuous concentration (CCC) was calculated to be 0.25mg/L. For PFOA, the CMC was calculated to be 45.54mg/L, and the CCC was calculated to be 3.52mg/L. The criteria derived in this study provide the scientific basis for development of water quality standards and aquatic ecosystem risk evaluation. [Copyright &y& Elsevier]

Abstract: The adsorption of on lake sediments has an important influence on the transport, degradation, and ultimate fate of P in lake ecosystems. Organic matter in sediment strongly affects adsorption, with light fraction organic matter (LFOM), the labile fractions representing only a small proportion of the total organic matter, playing a key role in nutrient cycling in lakes. However, little is known about the effect of LFOM on adsorption by sediments. This study examined the effects of LFOM removal on adsorption by lake sediments with different trophic status. Results showed that the removal of LFOM did not significantly affect adsorption kinetics, which was greatest during the first 0.5h and reached an equilibrium state thereafter. The amount of adsorbed decreased due to LFOM removal from the sediments, especially in the first 0.5h. The adsorption rates for the sediments from Gonghu Lake, Wuli Lake and Yuehu lake decreased from 302.44mg (kgh)−1 to 138.93mg (kgh)−1, 322.88mg (kgh)−1 to 149.21mg (kgh)−1 and 415.36mg (kgh)−1 to 46.77mg (kgh)−1, respectively. The removal of LFOM accelerated release from sediments to the overlying water, and adsorption efficiency decreased by 83.75%, 70.90% and 66.75% for Gonghu Lake, Wuli Lake and Yuehu Lake, respectively. Two plausible explanations contributed to the decrease, one was the replacement of which was in the form of Fe/Al-bound P in the sediment by OHhe increased pH, and the other is the destruction of LFOM colloids by the carboxyl group ( hydroxyl (–OH). [Copyright &y& Elsevier]