Effects of typical algae species（Aphanizomenon flosaquae and Microcystis aeruginosa） on photoreduction of Hg2+ in water body  

作　　者：Rongguo Sun Yafei Mo Xinbin Feng Leiming Zhang Lin Jin Qiuhua Li 

机构地区：[1]State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China [2]School of Chemistry and Material, Guizhou Normal University, Guiyang, China [3]Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, Ontario, Canada

出　　处：《Journal of Environmental Sciences》2019年第11期9-16,共8页环境科学学报（英文版）

基　　金：supported by the Science and Technology Department of Guizhou Province(No.Qiankehe LH zi [2017]7334hao);the China Postdoctoral Science Foundation(No.2017M613005);Foundation of Guizhou Educational Committee(No.Qian jiao he KY[2016]135);the National Natural Science Foundation of China(No.41563012);the Doctoral Scientific Research Foundation of Guizhou Normal University for 2014

摘　　要：Photoreduction characteristics of divalent inorganic mercury (Hg2+) in the presence of specific algae species are still not well known.Laboratory experiments were conducted in the present study to identify the effects of different concentrations of living/dead algae species,including Aphanizomenon flosaquae (AF) and Microcystis aeruginosa (MA),on the photoreduction rate of Hg2+ under various light conditions.The experimental results showed that percentage reduction of Hg2+ was significantly influenced by radiation wavelengths,and dramatically decreased with the presence of algae.The highest percentage reduction of Hg2+ was induced by UV-A,followed by UV-B,visible light and dark for both living and dead AF,and the order was dark > UV-A > UV-B > visible light for both living and dead MA.There were two aspects,i.e.,energy and attenuation rate of light radiation and excrementitious generated from algae metabolisms,were involved in the processes of Hg2+ photoreduction with the presence of algae under different light conditions.The percentage reduction of Hg2+ decreased from 15% to 11% when living and dead AF concentrations increased by 10 times (from 106 to 105 cells/mL),and decreased from11% to ~9% in the case of living and dead MA increased.Algae can adsorb Hg2+ and decrease the concentration of free Hg2+,thus inhibiting Hg2+ photoreduction,especially under the conditions with high concentrations of algae.No significant differences were found in percentage reduction of Hg2+ between living and dead treatments of algae species.The results are of great importance for understanding the role of algae in Hg2+ photoreduction.Photoreduction characteristics of divalent inorganic mercury(Hg2+) in the presence of specific algae species are still not well known. Laboratory experiments were conducted in the present study to identify the effects of different concentrations of living/dead algae species, including Aphanizomenon flosaquae（AF） and Microcystis aeruginosa（MA）, on the photoreduction rate of Hg2+under various light conditions. The experimental results showed that percentage reduction of Hg2+was significantly influenced by radiation wavelengths, and dramatically decreased with the presence of algae. The highest percentage reduction of Hg2+was induced by UV-A, followed by UV-B, visible light and dark for both living and dead AF, and the order was dark > UV-A > UV-B > visible light for both living and dead MA. There were two aspects, i.e., energy and attenuation rate of light radiation and excrementitious generated from algae metabolisms, were involved in the processes of Hg2+photoreduction with the presence of algae under different light conditions. The percentage reduction of Hg2+decreased from 15% to 11% when living and dead AF concentrations increased by 10 times（from 106 to 105 cells/mL）, and decreased from 11% to ～ 9% in the case of living and dead MA increased. Algae can adsorb Hg2+and decrease the concentration of free Hg2+, thus inhibiting Hg2+photoreduction, especially under the conditions with high concentrations of algae. No significant differences were found in percentage reduction of Hg2+between living and dead treatments of algae species.The results are of great importance for understanding the role of algae in Hg2+photoreduction.

关 键 词：APHANIZOMENON flosaquae MICROCYSTIS AERUGINOSA PHOTOREDUCTION DIVALENT inorganic mercury (Hg2+) 

分 类 号：X[环境科学与工程]