基于多元统计分析的辽东湾沉积物痕量金属地球化学特征

为研究辽东湾表层沉积物中痕量金属的地球化学特征和可能产生的生物效应,于2015年在辽东湾设置38个采样点,采集表层沉积物样品,测定其中13种痕量金属污染物的含量,并采用多元统计分析法对其地球化学特征进行研究. 结果表明:辽东湾表层沉积物中w(Al)、w(V)、w(Cr)、w(Mn)、w(Fe)、w(Co)、w(Ni)、w(Cu)、w(Zn)、w(As)、w(Cd)、w(Ba)和w(Pb)平均值分别为55 726.95、76.21、35.59、852.85、30 482.16、11.98、27.88、21.60、76.53、9.16、0.17、396.78和21.72 mg/kg；其中w(Al)最高,占63.51%；w(Fe)其次,占34.74%. 多元统计分析结果表明,痕量金属受氧化还原环境影响强烈,V、Co、Ni、Cu、Zn、As、Cd在沉积物的氧化还原循环中易被Fe氧化物吸附,与Fe氧化物产生共生关系. Ba与Pb存在共生关系,具有相似的物质来源和地球化学特征；Mn是海洋沉积物中主要化学成分；Cr一般和沉积物中的陆地碎屑相结合. 生态效应浓度评价表明,Ni和As偶尔会产生不利的生物效应,产生几率分别为97%和63%；Ni、As、Cu、Pb和Cr长期暴露会产生毒性效应,产生几率分别为100%、94%、74%、6%和3%,Zn和Cd不会产生毒性效应. 根据对生物产生负面效应和毒性效应的概率,痕量金属污染程度的排序为Ni＞As＞Cu＞Pb＞Cr＞Zn=Cd. 

Geochemical Characteristics of Trace Metals in Sediments of Liaodong Bay Based on Multivariate Statistical Analysis

Abstract: We collected 38 surface sediment samples from Liaodong Bay, the northern bay in the Bohai Sea of North China, in 2015, to investigate their geochemical characteristics and potential to cause toxic effects. The concentrations of 13 trace metals commonly found in sediments were determined. Multivariate statistics was used to establish the relationships between different parameters, and to examine the geochemical characteristics of the trace metals. The concentrations of aluminum (Al), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), barium (Ba) and lead (Pb) were 55,6.95,6.21,5.59,2.85,0,482.16,1.98,7.88,1.60,6.53,9.16,0.17,6.78 and 21.72 mg/kg, respectively. Statistical analysis results indicated that trace metal concentrations were influenced by internal redox conditions in the sediment; V, Co, Ni, Cu, Zn, As, and Cd were easily absorbed by Fe oxides in the surface sediments during redox cycling, and trace metal concentrations were closely related to Fe oxides. The relatively strong correlation between Ba and Pb suggests a common origin or similar geochemical behavior. Mn was the most plentiful metal in marine sediment, while Cr was generally associated with land debris in the sediment. The effects range-low (ERL), effects range-median (ERM), threshold effect level (TEL) and probable effect level (PEL) values reflect the toxic effects of trace metals and supports the prediction of biological effects in polluted marine sediments. Comparison of the trace metals with toxicological references indicated that there could be occasional adverse biological effects from Ni and As in surface sediments of Liaodong Bay, with probable rates of 97% and 63%, respectively. There may also be negative influences from long-time exposure to Ni, As, Cu, Pb and Cr, with probable rates of 100%, 94%, 74%, 6%, and 3%, respectively. Negative effects from Zn and Cd, however, would be rare. Based on the probable rates of negative impacts and toxic effects on organisms, the pollution potentials of the trace metals were ranked in the order:Ni>As>Cu>Pb>Cr>Cd=Zn.