渤海莱州湾表层沉积物中金属元素分布及环境质量

利用X-射线荧光光谱仪、等离子质谱仪或原子荧光光度计测定了莱州湾表层沉积物中金属元素的含量,探讨了它们的分布特征、来源及污染程度,结果表明,沉积物中铜、锌、铅、镉、砷、镍、铬、钴、钒、钪、铁、锰的含量由近岸向湾内递减,莱州湾北部海域的含量大于南部的。银含量高的沉积物主要分布在莱州湾中部偏西南的环流中心区。沉积物中砷和镍含量超过ERL值,潜在生态风险较高。富集系数和主成分分析显示,沉积物中铁、铜、锌、镉、砷、铬、镍、钴、锰、钒和钪为无富集,砷为轻度富集,铅和银为中度富集。铁、铜、锌、镉、铬、镍、钴、锰、钒、砷和钪主要来源于自然源,铅既有岩石和土壤风化产物硅酸盐矿物等自然源的贡献,又受到了人为活动的影响,银主要受人为活动的影响。聚类分析表明,可把莱州湾沉积物分为4类,其中黄河口西北缘沉积物中砷和镍污染生态风险最高,其次是莱州湾中部和北部。

The distribution and risk assessment of metals in surface sediments of the Laizhou Bay in the Bohai Sea

The contents of metals in surface sediments of the Laizhou Bay in the Bohai Sea were determined by the X-ray fluorescence, the inductively coupled plasma mass spectroscopy or the atomic fluorescence spectrometer. Results show that the contents of copper,zinc,lead,cadmium,nickel,chromium,cobalt,vanadium,scandium,iron and manganese decrease gradually from the coastal area to the central, and their contents are higher in the southern area than those in the northern. However, the relatively higher contents of silven were observed in the middle-southwestern sea of this area. A risk assessment of heavy metals, based on the marine sediment quality standards, indicates that adverse biological effects caused by arsenic and nickel occasionally may take place in the sediments of the Laizhou Bay. Enrichment factors were calculated to weigh whether the contents observed represented background or contaminate levels. The results reveal three groups of elements: (1)Iron,copper,zinc,cadmium,nickel,cobalt,manganese,vanadium and scandium are at background contents; (2)arsenic is the slight enriched element; and (3)lead and silven are the moderate enriched elements. A principal component analysis and EFs reveal that iron,copper,zine,cadmium,arsenic chromium,nickel,cobalt,manganese,vanadium and scandium are mainly originated from terrestrial (rock and soil)weathering, lead may have some anthropogenic sources, and silver in sediments is mainly derived from anthropogenic sources.A cluster analysis showed that the sediments from 31 stations could be divided into four groups. Two zones were identified to be relatively heavy contaminated by both arsenic and nickel in the bay. One was the northwest of the Huanghe Estuary and the other was the central-north side of the Laizhou Bay.