Dejin Xu, Haiyan Xiong, Qiuling Wu, Wenze Xiao, Stuart L. Simpson, Qiao-Guo Tan, Rong Chen, Minwei Xie
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引用次数: 0
Abstract
Assessing the risk of metal-contaminated sediments under disturbed conditions is challenging due to the lack of methods that capture instant changes in metal bioavailability. Existing approaches provide inadequate understandings of the processes regulating metal bioavailability under nonequilibrium conditions. Experiments were conducted to improve our understanding of the metal bioavailability dynamics induced by sediment resuspension and subsequent redeposition (reequilibration). An isotopically modified bioassay, a novel stable isotope tracing technique, was used to measure metal bioavailability (assimilation rates) to clams within short time windows. Changes in metal partitioning were characterized by porewater analysis using in situ extraction and the diffusive gradients in thin-films technique. Results showed that sediment resuspension released metals into porewater, while reequilibration scavenged metals from the porewater. The assimilation rates of Ni, Cu, and Pb increased with the resuspension time, aligning with increasing porewater concentrations. Unexpectedly, during reequilibration, the metal assimilation rates did not decrease. The discrepancies between bioavailability to the clam and porewater extrapolations may be due to differing sustained conditions of metals in sediments. Overall, this study unveils the metal bioavailability dynamics in nonequilibrium sediments, which could not be accurately predicted relying solely on porewater analysis. Incorporating rapid bioassays to determine bioavailability offers a valuable tool for robust ecological risk assessment.
期刊介绍:
Environmental Science & Technology (ES&T) is a co-sponsored academic and technical magazine by the Hubei Provincial Environmental Protection Bureau and the Hubei Provincial Academy of Environmental Sciences.
Environmental Science & Technology (ES&T) holds the status of Chinese core journals, scientific papers source journals of China, Chinese Science Citation Database source journals, and Chinese Academic Journal Comprehensive Evaluation Database source journals. This publication focuses on the academic field of environmental protection, featuring articles related to environmental protection and technical advancements.