纳米银对河口潮滩硝酸盐异化还原成铵过程的影响  

Effects of silver nanoparticles on dissimilatory nitrate reduction in estuarine and tidal sediments

作　　者：张梦霞 郑艳玲[2,3] 尹国宇[2,3] 董宏坡 韩平 高娟[1] 刘程[1] 常永凯 刘敏[2,3] 侯立军[1] ZHANG Mengxia;ZHENG Yanling;YIN Guoyu;DONG Hongpo;HAN Ping;GAO Juan;LIU Cheng;CHANG Yongkai;LIU Min;HOU Lijun(State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200241,China;Key Laboratory of Geographic Information Science(Ministry of Education),East China Normal University,Shanghai 200241,China;School of Geographic Sciences,East China Normal University,Shanghai 200241,China)

机构地区：[1]华东师范大学河口海岸学国家重点实验室,上海200241 [2]华东师范大学地理信息科学教育部重点实验室,上海200241 [3]华东师范大学地理科学学院,上海200241

出　　处：《华东师范大学学报（自然科学版）》2020年第3期68-77,共10页Journal of East China Normal University(Natural Science)

基　　金：国家重点研发计划(2016YFA0600904);国家自然科学基金(41725002,41671463,41130525,41322002,41601530)。

摘　　要：人类活动会导致纳米银(AgNPs)毒性污染物在河口海岸环境富集,但AgNPs赋存和累积对河口氮转化过程的影响尚不清楚.为此,以长江口作为研究区域,对不同粒径(10 nm、30 nm和100 nm)及不同浓度(0.1 mg/L、5 mg/L和10 mg/L)的AgNPs进行暴露实验,探究AgNPs对河口潮滩硝酸盐异化还原成铵(DNRA)的影响.结果表明,添加AgNPs对不同盐度沉积物DNRA速率均产生一定程度的抑制效应,但其抑制率并没有随时间增长而明显增大.受沉积物理化性质的影响,AgNPs对中盐度(8.0‰)沉积物DNRA速率抑制效应总体上高于其余盐度沉积物.沉积物环境中AgNPs的粒径及浓度均是影响其毒性的重要因素:当浓度不超过5 mg/L时,10 nm粒径AgNPs毒性大于30 nm和100 nm粒径,其在不同盐度沉积物中抑制率最高达16.03%、20.27%和15.36%;但当AgNPs浓度为10 mg/L时,30 nm和100 nm粒径的AgNPs对DNRA速率抑制程度明显增大,毒性效应大于10 nm粒径AgNPs,不同盐度沉积物中最大抑制率分别为17.48%、33.18%和26.45%.AgNPs释放的Ag+浓度与DNRA速率的抑制率未存在显著的正相关关系(p>0.05),反映AgNPs释放的Ag+对DNRA存在一定的抑制作用,但并不能完全解释AgNPs的毒性作用特征.研究结果对于客观评价金属纳米材料对河口氮循环的潜在影响具有重要科学意义.Human activity can cause accumulation of silver nanoparticles(AgNPs)in estuarine and coastal environments;however,the effects of accumulated AgNPs on nitrogen transformation remain unclear.This study investigated the effects of AgNPs on dissimilatory nitrate reduction to ammonium(DNRA)rates in Yangtze estuarine and intertidal sediments using exposure experiments with three different sizes of AgNPs(10 nm,30 nm,and 100 nm)and three different AgNPs concentrations(0.1 mg/L,5 mg/L,and 10 mg/L).The results showed that AgNPs inhibited DNRA rates of sediments with different salinity levels,but the inhibition did not increase significantly with time.AgNPs had relatively high inhibition in medium salinity areas depending on the physical properties of the respective sediments.Moreover,it was shown that both the size and concentration of AgNPs were important factors affecting their toxicity.When the concentration of AgNPs was≤5 mg/L,the inhibition of 10 nm AgNPs on the DNRA rate was greater than those of 30 nm and 100 nm AgNPs;the strongest inhibition effects among different salinities reached 16.03%(at 0.2‰salinity),20.27%(at 8.0‰salinity),and 15.36%(at 20‰salinity).However,when the concentration of AgNPs was 10 mg/L,the inhibition of 30 nm and100 nm AgNPs on the DNRA rate under the same salinities increased to 17.48%,33.18%,and26.45%,respectively;these values were larger than the inhibition of 10 nm AgNPs.There was no significant correlation between Ag+concentration and the inhibition of AgNPs on the DNRA rate(p>0.05),indicating the inhibitory effect of AgNPs on the DNRA rate could not be fully explained by the toxicity of Ag+.These results are of great significance to understand the influence of emerging pollutants on the estuarine nitrogen cycle.

关 键 词：纳米银 硝酸盐异化还原为铵 粒径 盐度 长江口 

分 类 号：X171.1[环境科学与工程—环境科学]