渤海湾近岸人工鱼礁区表层沉积物重金属分布特征及生态风险评价

Distribution characteristics and ecological risk assessment of heavy metals in surface sediments around artificial reefs in offshore area of Bohai Bay

目的了解渤海湾近岸不同年份构建的人工鱼礁区表层沉积物重金属空间分布特征及其潜在的生态风险。方法分别在2010、2012、2014年构建的人工鱼礁区及附近未投放人工鱼礁的海域(对照区)各设三个站位共采集12个沉积物样品,运用电感耦合等离子体质谱法测定沉积物中Cu、Pb、Zn、Cd、As、Cr 6种重金属元素的含量,并运用地累积指数(I_(geo))和潜在生态风险指数(RI)对沉积物重金属污染状况和生态风险进行评价。结果沉积物中Cu、As、Pb含量顺位为对照区>2014年人工鱼礁区>2012年人工鱼礁区>2010年人工鱼礁区;Zn,Cr,Cd的含量顺位为对照区>2014年人工鱼礁区>2010年人工鱼礁区>2012年人工鱼礁区。Igeo指数表明Cd达到严重污染程度,Cu,As为轻度偏中度污染,其他重金属无污染。RI指数表明2010年和2012年人工鱼礁区潜在生态风险程度均为中度,2014年人工鱼礁区与对照区均为重度。结论本次调查的人工鱼礁区表层沉积物中Cd的污染应引起关注,投礁年限长的鱼礁区表层沉积物重金属污染较轻。

Objective To explore the distribution characteristics and ecological risk assessment of heavy metals in surface sediments around artificial reefs in offshore area of Bohai Bay used to analyze the horizontal distribution of six heavy metals Methods Inductively coupled plasma-mass spectrometry was （Cu, Pb, Zn, Cd, As, Cr） in surface sediments around artificial reefs buih in different years in offshore area of Bohai Bay. The geo-accumulation index （Igeo） and the Hakanson potential ecological risk index （R1） were applied for assessing the status of heavy metals enrichment in surface sediment and the extent of potential ecological risk. Results The average contents of heavy metals Cu,As,Pb followed the order, blank area 〉2014 artificial reefs（established in 2014） 〉2012 artificial reefs （established in 2012）〉2010 artificial reefs （established in 2010）. The average contents of heavy metals Zn, Cr, Cd followed the order, blank area 〉2014 artificial reefs〉2010 artificial reefs〉2012 artificial reefs. The Igeo, result showed that the pollution extent and potential ecological risk of Cd was the most serious among all heavy metals, Cu, As came after Cd. Analysis showed that heavy metals pollution and the potential ecological risk in the four area followed order： blank area 〉2014 artificial reefs〉2012 artificial reefs〉2010 artificial reefs. Conclusion The contamination by Cd in the investigated surface sediments of artificial reefs should be paid more attention to.