大气CO2浓度升高对砷污染水体生态风险的影响  

Elevated CO_2 levels affects the ecological risk of arsenic pollution water

作　　者：孙曙光[1] 尹颖[1] 郭红岩[1] 

机构地区：[1]污染控制与资源化研究国家重点实验室,南京大学环境学院,南京210046

出　　处：《南京大学学报（自然科学版）》2013年第3期387-393,共7页Journal of Nanjing University（Natural Science）

基　　金：水利部公益型项目(201001010)

摘　　要：本文在开顶式气室OTC(Open Top Chamber)平台下,构建水生微宇宙系统.通过向底泥中外源添加砷的方式污染水体.初步研究了当CO2浓度升高至550～650μmol/mol时,通气一段时间后,水体理化参数pH、Eh的变化规律.参照US Environmental Protection Agency慢性毒性标准测试方法,探究了不同处理组水体综合毒性的大小,并以此来指示不同大气条件下砷污染水体生态风险的变化规律.结果表明:通气一年后,与正常大气条件相比,CO2升高条件下清洁水体的pH降低了0.47,Eh降低了13.12mv;砷污染水体pH降低了0.58,Eh降低了12.68mv;底泥中pH和Eh也有降低趋势.羊角月牙藻和大型蚤慢性毒性测试结果表明:CO2升高条件下,砷污染水体对羊角月牙藻的生长抑制作用强于正常大气条件下砷污染水体,且CO2浓度的升高也加剧了砷污染水体对大型蚤繁殖能力的抑制作用,两种生物毒性测试的结果基本一致.表明CO2浓度升高加剧了砷污染水体的生态风险,但导致风险加剧的机理还有待进一步研究.With increasing global industrialization, the atmospheric COe concentration has risen from approximately 280 μ mol/mol in preindustrial times to approximately 380/,mol/mol now,and it is expected to continue increasing in the future. Increasing atmospheric CO2 causes climate warming and ocean acidification problems. It affects photosynthesis of submerged plant and floating algae in the water and changes community structure of aquatic organisms. The speciation of the minor elements together with the concentration of dissolved organic matter（DOM） in the water can also be affected, thus bioavailability of minor elements will be changed. Arsenic is a ubiquitous element, which occurs naturally in the earth＇s crust. It has been used in various fields such as medicine, electronics, agriculture and metallurgy. Human activities such as mining, the burning of fossil fuels, and pesticide application are the main sources of arsenic pollution. Arsenic is toxic to both plants and animalsand inorganic arsenicals are proven carcinogens in humans. A wide range of arsenic toxicity has been determined that depends on arsenic speciation. Recently,arsenic pollution accidents happened occasionally in China＇s lakes and rivers, which poses serious threat to the aquatic environment safety. Because of the chronic toxicity effects of arsenic,long- term exposure to low concentration arsenic is still harmful to aquatic organisms. In the future,the concentration of atmospheric CO2 will continue increasing, meanwhile, the living environment of aquatic organism, the speciation of arsenic,and the concentration of arsenic adsorbed onto the surface of DOM or metal oxides will be changed. Will these changes aggravate or alleviate the ecological risk of arsenic pollution water？ It is a question to be answered. This article simulated aquatic microcosms under Open Top Chamber（OTC）with 550~650 t^mol/mol of CO2. The ecological risk of arsenic pollution water was studied in these aquatic microcosms. The water was polluted by adding sodium

关 键 词：CO2浓度 砷污染 水生生态系统 生物毒性 

分 类 号：X52[环境科学与工程—环境工程]