胶州湾沉积物柱状样重金属垂向分布特征及其控制因素

于2011年在胶州湾采集一根沉积物柱状样，分析了0～1 m不同层次沉积物样品中汞（Hg）、砷（As）、镉（Cd）、铬（Cr）、铜（Cu）、镍（Ni）、铅（Pb）和 锌（Zn）等8种重金属含量并计算富集因子指数（enrichment factors, EF，代表元素富集程度）。结果表明，多数重金属在次表层20 cm左右浓度和EF值都达到峰值或有一个高值区，这可能主要是由上世纪八九十年代胶州湾周边区域高强度人为排放的重金属导致的。进一步通过Pearson相关分析和多元线性回归分析探讨了控制胶州湾沉积物重金属垂向分布的关键因素，结果发现8种重金属的关键控制因素不同。采用沉积物潜在生态风险指数法评估了胶州湾重金属的生态风险及历史变化趋势，发现8种重金属中Hg风险较高，整体处于中等风险水平，且近年来风险还呈一定增大趋势，应列为胶州湾优先控制重金属。

The vertical distribution patterns of heavy metals in a sediment core of the Jiaozhou bay and their controlling factors

A sediment core was collected in the Jiaozhou bay in 2011. The concentrations of eight heavy metals mercury (Hg), arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn)] in the sediment core from 0 m to 1 m were measured. These raw data were then utilized to calculate the enrichment factors (enrichment factors, EFs, represents the enrichment status of elements) of these metals. The results showed that both concentrations and EFs of these heavy metals presented a peak or had the highest value in the subsurface layer (at around 20 cm) of the sediment core. The age of sediment at such depth was estimated to be around 20 years using the reported sediment settlement rate. This indicates that the contamination of heavy metals in Jiaozhou bay sediment may be significantly affected by the high-intensity anthropogenic discharge of heavy metals into the Jiaozhou bay in the late 1980s and 1990s. Pearson correlation and multiple regression analyses were further performed to investigate the primary controlling factors for heavy metals in Jiaozhou bay sediment. The results suggest that the inter-annual variations of the eight common heavy metals may be controlled by different environmental factors in Jiaozhou bay sediment. In addition, the potential ecological risk index was calculated to evaluate the potential risks of these heavy metals in Jiaozhou Bay sediment and their historical variation trends. Mercury generally had a moderate risk in the Jiaozhou bay, and its risk has been increasing in recent years. This finding suggests that Hg should be put in the priority metal to be controlled in the Jiaozhou bay.