摘要
在酸挥发性硫化物AVS存在的情况下,水体沉积物中的重金属的生物有效性将显著降低,同步提取金属SEM与AVS的比值SEM/AVS可作为判定重金属生物有效性的良好指标。本文通过研究东湖三个不同富营养化水平的站点的AVS的季节、深度变化特征及相关的影响因子,发现AVS的含量夏季要高于冬季,并随深度的加深呈先增高后降低的分布特征,SEM/AVS随深度的变化则呈现出先降低后升高的分布特征。研究结果为正确应用SEM/AVS指标判定沉积物中重金属的生物有效性提供了依据。
Acid-volatile sulfides (AVS), which can form insoluble sulfides complexes with minimal biological availability with a number of cationic metals, is a key partitioning phase controlling metal activity in the sediments. The ratio of simultaneous extracted metal (SEM) to AVS is promising to predict metal toxicity. It was found that the sediments with SEM/AVS≤1 were of no metal toxicity and may be toxic with SEM/AVS > 1. The authors investigated the seasonal and vertical distribution of AVS and SEM in the sediments cores of Lake Donghu. It was found that AVS is higher in summer than that in winter. It increases early and then decrease during the top 20cm layer of the sediments. This variation in AVS levels is attributed to temperature and sulfide oxidation in the suboxic top layer and sulfate reduction in the underlaying anoxic sediment layer. Comparison with AVS, SEM vertical distribution is not obvious. Thus, the SEM/AVS ratio first drops from 1 to less than 1, and then increases at greater depthes, even higher than one in same case. The results indicate that SEM/AVS ratios in mixed homogenized and single seasonal samples are generally not suitable for the assessment of potential metal toxicity of sediments.
出处
《水生生物学报》
CAS
CSCD
北大核心
2002年第3期239-245,共7页
Acta Hydrobiologica Sinica
基金
中国科学院重大项目A(KE951-A1-202)
