摘要
养殖废水同时含有重金属、抗生素等污染物.为明确微藻净化此类复合污染废水的潜力,需要系统研究抗生素与重金属对微藻的毒性作用,以及抗生素对微藻重金属富集规律的影响.基于此,以养殖废水中的典型重金属铜(Cu)、锌(Zn)以及抗生素四环素(tetracycline,TC)处理小球藻4 d,测定藻细胞的生长、叶绿素和胞外聚合物(extracellular polymeric substances,EPS)荧光类物质含量、以及对Cu、Zn的去除、吸附与吸收等指标.结果表明:Cu(0.1、0.5、1 mg/L)、Zn(0.5、5 mg/L)抑制了小球藻生长与叶绿素合成,诱导了EPS荧光类物质的分泌.1、5、10 mg/L的TC没有抑制小球藻生长,并且缓解了Cu、Zn对小球藻的毒性,使EPS中酪氨酸类蛋白物质的荧光强度降低.TC对小球藻去除Cu、Zn的影响存在差异:TC、Cu复合处理1 d后,相较于单一Cu处理,Cu的去除率由25.9%显著上升至43.5%,而TC对Zn的去除率无显著影响.TC也影响了Cu、Zn富集方式:Cu、Zn单一处理下,Cu、Zn吸附占富集的比例分别为16.89%、51.6%,TC的添加使两者增加至44.49%、86.73%.本研究表明,TC改变了Cu、Zn在小球藻细胞内外的分布,通过增加Cu、Zn的胞外吸附促进了小球藻对Cu的去除,通过减少Cu、Zn的胞内吸收降低了Cu、Zn对小球藻的毒性.
Livestock wastewater contains pollutants such as heavy metals and antibiotics.To clarify the potential of microalgae to clean up such wastewater with combined pollution,it is necessary to systematically study the joint toxicity of antibiotics and heavy metals on microalgae and the effects of antibiotics on heavy metal accumulation.As such,Chlorella sp.was exposed to 4-day treatments of two heavy metals-copper(Cu)and zinc(Zn),and antibiotics-tetracycline(TC),which are typical pollutants found in livestock wastewater.We measured the algal growth,chlorophyll contents,and fluorescent substances in extracellular polymeric substances(EPS)and the removal,adsorption,and absorption of Cu and Zn by Chlorella sp.The results showed that Cu(0.1,0.5,and 1 mg/L)and Zn(0.5 and 5 mg/L)inhibited the algal growth and chlorophyll synthesis and induced the secretion of EPS fluorescent substances.In contrast,TC(1,5,and 10 mg/L)did not inhibit the growth of the Chlorella sp.,alleviated the toxicity of Cu and Zn to the algae,and reduced the fluorescent intensity of tyrosine protein-like substances in the algal EPS.There are differences in the effects of TC on Cu and Zn removal rates.Under the single Cu treatment,the Cu removal rate by Chlorella sp.was 25.9%.It increased significantly to 43.5%under the combined treatment of TC and Cu for one day.However,the coexistence of TC and Zn did not influence the Zn removal rate by the algal cells.Meanwhile,TC affected the Cu and Zn accumulation pattern by Chlorella sp.Upon the single treatment of Cu and Zn,the adsorption ratio in the accumulation of Cu and Zn was 16.89%and 51.6%,respectively.After adding TC,these values increased to 44.49%and 86.73%.In summary,TC changed the accumulation pattern of Cu and Zn and promoted the removal of Cu by Chlorella sp.by increasing the extracellular adsorption of Cu and Zn,and alleviated the toxicity of Cu and Zn to algal cells by reducing the intracellular absorption of Cu and Zn.
作者
相满城
于清男
葛滢
张春华
XIANG Mancheng;YU Qingnan;GE Ying;ZHANG Chunhua(College of Resources and Environmental Sciences,Nanjing Agricultural University,Nanjing 210095,China;Life Science Experimental Center,Nanjing Agricultural University,Nanjing 210095,China)
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2024年第1期144-150,共7页
Chinese Journal of Applied and Environmental Biology
基金
国家自然科学基金项目(32171623)资助。
关键词
小球藻
铜
锌
四环素
毒性
富集
Chlorella sp.
copper
zinc
tetracycline
toxicity
accumulation
