摘要
采集子牙河干流河流沉积物,分析6种重金属(Cd、Cr、Cu、Ni、Pb和Zn)的分布特征,进而通过富集系数和相关性分析探讨其来源,并采用潜在生态风险指数评价重金属的环境风险。结果表明,子牙河干流沉积物重金属呈现明显的空间差异和垂直分布差异。中游河段(即邯郸下游到献县之间)重金属质量比较高,以Zn为例,其在中游、上游和下游的质量比分别为88.77 mg/kg、19.36 mg/kg、14.08mg/kg;Cr、Cu、Pb、Zn在中游沉积物中质量比均超过上游和下游的2倍以上,呈现相似的空间分布特征。在垂直剖面上,重金属质量比在20cm深度左右以下增长趋势不明显,之上呈现逐渐增加的趋势,Cr、Cu、Pb、Zn在上层沉积物中的质量比分别超过底层的2.47倍、2.13倍、1.47倍、3.6倍。据富集系数推断,沉积物中Cd、Cr、Cu、Pb、Zn主要来源于人为活动,Ni主要来源于自然过程。中游河段沉积物重金属富集程度高于上游和下游,滏阳新河富集最严重,Cr、Cu、Pb、Zn的富集系数分别为2.27、1.21、3.97、2.88。沉积物重金属生态风险指数评价的结果表明,子牙河干流表层沉积物重金属污染处于轻微生态风险程度,而Cd累积的生态风险问题较为突出。
The paper is to present our investigation results on the dis- tributive features and risk assessment of heavy-metal pollutants in the sediments of the main stream of Ziya River. Six 50-cm-deep sediment points were sampled with each of them in the main stream area, namely, the Fuyang River. For our research purpose, we have cho- sen the six points in the main streams of the river, including Fuyang River, Beili River, Fuyang New River, the Ziya River and the Ziya New River. The six heavy metal pollutants are cadmium, chromium, copper, nickel, lead and zinc. In proceeding with our research, we have analyzed the above said samples at different depths of each sedi- ment point. We have also studied the spatial and temporal distribution characteristics, including the enrichment factors （EF） and correlative factors of Cd, Cr, Cu, Ni, Pb and Zn in detail with the sources of the six heavy metals deduced. Besides, we have conducted ecological risk assessment of such metal contaminants by using the single and aggregative potential ecological risk indexes and in turn put forward our suggestions on the river environment management in the future. The results of our investigation have shown that there exist both spa- tial difference and temporal variation in the contents of such heavy metal contaminants. The average content of Zn in the sediment sam- ples from the midstream, the upstream and the downstream of the main stream of Ziya River are 88.77 mg/kg, 19.36 mg/kg, 14.08 mg/kg, respectively, whereas those of Cr, Cu and Pb from the mid- dle reach all account for over twice as much as those from the up- stream and downstream reaches, thus, revealing that the same spatial distribution characteristics to Zn. The increasing contents of Cd, Cr, Cu, Pb and Zn in the deeper layers to surface ones of the sediment sample cores indicate a noticeable accumulation of the said heavy metals. Moreover, the average content of Cr, Cu, Pb and Zn in the subsurface sediments at the depth beneath the 20 cm were 2.47 times, 2.13 times, 1.47 times and 3.6 times of those in the bottom sediments in a depth below 20 cm. Thus, it can be inferred that Cd, Cr, Cu, Pb and Zn were mainly originated from the anthropogenic activities while Ni was originated from the natural processes, as a re- sult of analysis of the enrichment factor and the correlative analysis of the sediment contents of the said six metals. At the upper 5cm depth of the sediment samples, the enrichment degree of heavy metals from the midstream proved to be all higher than those from the upstream and downstream reaches. As to the Fuyang New River, we have no- ticed the most serious accumulation of Cr, Cu, Pb and Zn, with EFs of 2.27, 1.21, 3.97, and 2.88, respectively. The results of the above mentioned ecological risk assessment reveal that heavy metals in the surface sediments of the area under study had a slight ecologi- cal risk with the average aggregative potential ecological risk index （RI） of 47.86, however, the potential ecological risk indices （E^if） of Cd belongs to the middle level environmental risk.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2014年第1期253-257,共5页
Journal of Safety and Environment
基金
水体污染控制与治理科技重大专项(2012ZX07203-006)
关键词
环境学
子牙河
重金属
分布特征
风险评价
environmentaloogy
Ziya River
heavy metal
distribu-tion characteristics
risk assessment
