多种痕量元素对鳗草毒性的半效应浓度研究:以地上部分伸长长度和最大光量子产量为指标

Study on toxicity by half-effect concentrations of trace elements in eelgrass:aboveground elongation length and maximum light quantum yield as indexes

海草床是重要的近岸海洋生态系统之一。痕量元素污染是造成沿海海草床退化的原因之一。鳗草(Zostera marina L.)是温带海域最广泛分布的海草种。本文通过室内模拟实验,以鳗草地上部分伸长长度和最大光量子产量(Fv/Fm)为评价指标,研究了砷、铬、汞、镍、纳米银、锌6种痕量元素胁迫下对鳗草的毒性效应,并确定6种痕量元素对鳗草的半效应浓度(EC_(50))。结果表明,6种元素均对鳗草地上部分伸长长度和Fv/Fm产生了抑制作用,NaAsO_(2)、Na_(2)CrO_(4)·4H_(2)O、HgCl_(2)、AgNPs、NiSO_(4)·6H_(2)O、ZnSO_(4)·7H_(2)O对鳗草的半效应浓度分别为2.1 mg/L(As:16.0μmol/L)、89.8 mg/L(Cr:384.6μmol/L)、0.65 mg/L(Hg:2.2μmol/L)、8.1 mg/mL(Ag:75.0μmol/L)、3.0×10^(3) mg/L(Ni:1.1×10^(4)μmol/L)、7.5×10^(4) mg/L(Zn:2.6×10^(5)μmol/L),不同痕量元素对鳗草的毒性大小为Hg>As>AgNPs>Cr>Ni>Zn。本文研究结果将为受损海草床的生态修复及保护管理提供科学依据。

Eelgrass has a complete structure consisting of roots,stems,and leaves and completes its entire life cycle in seawater.In this study,the toxic effects of sodium arsenite(NaAsO_(2)),sodium chromate tetrahydrate(Na_(2)CrO_(4)·4H_(2)O),mercury chloride(HgCl_(2)),nano-silver(AgNPs),nickel sulfate hexahydrate(NiSO_(4)·6H_(2)O),and zinc sulfate heptahydrate(ZnSO_(4)·7H_(2)O)on eelgrass were studied through laboratory simulation experiments.The different concentrations used for inducing stress were NaAsO_(2)(0,1,2,4,and 8 mg/L),Na_(2)CrO_(4)·4H_(2)O(0,20,40,80,and 120 mg/L),HgCl_(2)(0,0.4,0.5,0.6,and 0.7 mg/L),AgNPs(0,1,4,7,and 10 mg/L),NiSO_(4)·6H_(2)O(0,1×10^(3),3×10^(3),5×10^(3),and 10×10^(3)mg/L),and ZnSO_(4)·7H_(2)O(0,0.01×10^(3),0.05×10^(3),0.1×10^(3),0.5×10^(3)mg/L).The partial elongation length and maximum light quantum yield(Fv/Fm)were inhibited by all six elements.The half-effect concentrations of NaAsO_(2),Na_(2)CrO_(4)·4H_(2)O,HgCl_(2),AgNPs,NiSO_(4)·6H_(2)O,and ZnSO_(4)·7H_(2)O were 2.1 mg/L(As:16.0μmol/L)and 89.8 mg/L(Cr:384.6μmol/L),0.65 mg/L(Hg:2.2μmol/L),8.1 mg/Ml(Ag:75.0μmol/L),3.0×10^(3)mg/L(Ni:1.1×10^(4)μmol/L),7.5×10^(4)mg/L(Zn:2.6×10^(5)μmol/L).The toxicity was in the order of Hg>As>AgNPs>Cr>Ni>Zn.