摘要
随着纳米银的广泛使用,纳米银和重金属共同暴露的环境风险也逐渐增加。六价铬(Cr(Ⅵ))是污水处理厂主要存在的重金属之一,为了阐明纳米银和Cr(Ⅵ)的复合效应和环境影响,采用不同浓度的纳米银和Cr(Ⅵ)共同暴露于污水生物处理系统中,通过考察其对污水生物处理的复合影响,揭示二者潜在的生态风险。结果表明:(1)当纳米银≤1.0 mg/L、Cr(Ⅵ)为20.0 mg/L时,二者共同暴露对生物去除污水中有机物和氨氮没有产生复合毒性效应,但降低了污水的生物除磷效率和减缓了污泥粒径的增长速率;(2)当Cr(Ⅵ)为20.0 mg/L时,出水中总铬急剧升高,在20 d后达到14.6 mg/L,而出水中总银没有出现趋势性变化。因此,纳米银和Cr(Ⅵ)共同暴露对污水生物处理产生了不利的复合影响。鉴于自然条件下污染物赋存环境的多样性,纳米银和Cr(Ⅵ)共同暴露所引起的复合生态风险不容忽视。
With the widespread use of silver nanoparticles(AgNPs),the environmental risk caused by the co-exposure of AgNPs and heavy metals is gradually increased.Cr(Ⅵ)is one of major heavy metals in the sewage treatment plants.In order to demonstrate the synergistic effect and environmental influence,the sewage biological treatment system was exposed in the different concentrations of AgNPs and Cr(Ⅵ),which was used to investigate the synergistic effect on the sewage biological treatment,and further revealed the potential ecological risks.The results showed:(1)the co-exposure of AgNPs and Cr(Ⅵ)did not have a synergistic toxic effect on the removal of organic matter and ammonia nitrogen under the operating conditions as the amounts of AgNPs and Cr(Ⅵ)were≤1.0 and 20.0 mg/L,respectively,but it could decrease the phosphorus removal efficiency,and retard the growth rate of sludge particle size.(2)The concentration of total chromium was sharply increased in the effluent due to the exposure of 20.0 mg/L Cr(Ⅵ),the concentration could reach 14.6 mg/L after 20 d exposure.However,the trend change of total silver was not found in the effluent.Therefore,the co-exposure of AgNPs and Cr(Ⅵ)brought about a negative synergistic effect on sewage biological treatment.In view of the diversity of pollutant occurrence environments under natural conditions,the composite ecological risks caused by the co-exposure of AgNPs and Cr(Ⅵ)cannot be ignored.
作者
周婷婷
宋晓梅
郑煜铭
苑志华
ZHOU Tingting;SONG Xiaomei;ZHENG Yuming;YUAN Zhihua(CAS Key Laboratory of Urban Pollutant Conversion,Institute of Urban Environment,Chinese Academy of Sciences,Xiamen Fujian 361021;University of Chinese Academy of Sciences,Beijing 100049;School of Earth and Environment,Anhui University of Science and Technology,Huainan Anhui 232001)
出处
《环境污染与防治》
CAS
CSCD
北大核心
2022年第4期431-437,共7页
Environmental Pollution & Control
基金
国家自然科学基金资助项目(No.21407142)
厦门市科技计划资助项目(No.3502Z20203076)。
关键词
纳米银
六价铬
污水生物处理
复合毒性
silver nanoparticles
Cr(Ⅵ)
sewage biological treatment
synergistic toxicity
