Dept. of Biology, McMaster University, Hamilton, ON L8S4K1, Canada.
Comp Biochem Physiol C Toxicol Pharmacol. 2013 Aug;158(2):72-83. doi: 10.1016/j.cbpc.2013.04.004. Epub 2013 Apr 18.
Lead (Pb) EC50 values in the very sensitive early development phases (48-72h post-fertilization) of the mussels Mytilus galloprovincialis and Mytilus trossolus and sea urchin Strongylocentrotus purpuratus in 100% sea water were: M. trossolus - 45 (95% C.I.=22-72) μgL(-1); M. galloprovincialis - 63 (36-94) μgL(-1); S. purpuratus - 74 (50-101) μgL(-1). Salinity thresholds for normal development varied: M. trossolus>21ppt; M. galloprovincialis>28ppt; S. purpuratus≥30ppt. Addition of two spectroscopically distinct dissolved organic matters (DOM) from fresh water (Nordic Reservoir) and sea water (Inshore) moderately decreased the toxicity of Pb to both mussels, but not in a concentration-dependent fashion, with only an approximate doubling of EC50 over the range of 1.4-11.2mgCL(-1). Independent Pb binding capacity determinations for DOC explained the lack of a relationship between DOM concentration and toxicity. Salinity had no effect on Pb toxicity down to 21ppt in M. trossolus, and low salinity (21ppt) did not enhance the protective effect of DOC. Both DOMs increased the toxicity of Pb in developing sea urchin embryos, in contrast to mussels. Relative to Pb, the organisms were 6-9 fold less sensitive to Zn on a molar basis in 100% seawater with the following Zn EC50s: M. trossolus - 135 (103-170) μgL(-1); M. galloprovincialis - 172 (126-227) μgL(-1), S. purpuratus - 151 (129-177) μgL(-1). Nordic Reservoir and Inshore DOM (2-12mgCL(-1)) had no significant effect on Zn toxicity to mussels, in accord with voltammetry data showing an absence of any strong ligand binding for Zn by DOMs. As with Pb, DOMs increased Zn toxicity to urchin larvae. Critical Tissue Residues (CTR) based on whole body concentrations of Pb and Zn were determined for M. galloprovincialis at 48h and S. purpuratus at 72h. The median lethal CTR values (LA50s), useful parameters for development of saltwater Biotic Ligand Models (BLMs), were approximately 4-fold higher on a molar basis for Zn than for Pb. The latter were not altered by DOM exposure, despite increased EC50 values, in accord with the tenets of the BLM.
在贻贝（Mytilus galloprovincialis 和 Mytilus trossolus）和海胆（Strongylocentrotus purpuratus）受精后 48-72 小时的非常敏感的早期发育阶段，铅（Pb）的 EC50 值在 100%海水中为：贻贝 M. trossolus-45（95%置信区间=22-72）μgL(-1)；贻贝 M. galloprovincialis-63（36-94）μgL(-1)；海胆 S. purpuratus-74（50-101）μgL(-1)。正常发育的盐度阈值有所不同：贻贝 M. trossolus>21ppt；贻贝 M. galloprovincialis>28ppt；海胆 S. purpuratus≥30ppt。两种来自淡水（北欧水库）和海水（近岸）的具有明显不同光谱特征的溶解有机物（DOM）的添加适度降低了 Pb 对两种贻贝的毒性，但不是浓度依赖性的，仅在 1.4-11.2mgCL(-1)范围内 EC50 约增加一倍。DOC 的独立 Pb 结合能力测定解释了 DOM 浓度与毒性之间缺乏关系。在贻贝 M. trossolus 中，盐度在 21ppt 以下对 Pb 毒性没有影响，低盐度（21ppt）并没有增强 DOM 的保护作用。与贻贝相反，两种 DOM 都增加了发育中海胆胚胎中 Pb 的毒性。与 Pb 相比，在 100%海水中，这些生物对 Zn 的敏感性按摩尔计算低 6-9 倍，Zn 的 EC50 如下：贻贝 M. trossolus-135（103-170）μgL(-1)；贻贝 M. galloprovincialis-172（126-227）μgL(-1)，海胆 S. purpuratus-151（129-177）μgL(-1)。北欧水库和近岸 DOM（2-12mgCL(-1)）对贻贝中 Zn 的毒性没有显著影响，这与伏安法数据一致，表明 DOM 对 Zn 没有任何强配体结合。与 Pb 一样，DOM 增加了海胆幼虫中 Zn 的毒性。基于贻贝 M. galloprovincialis 在 48 小时和海胆 S. purpuratus 在 72 小时时的体内全浓度，确定了 Pb 和 Zn 的临界组织残留（CTR）。基于摩尔的中位致死性 CTR 值（LA50）对于开发海水生物配体模型（BLM）是有用的参数，Zn 的数值约为 Pb 的 4 倍。尽管 EC50 值增加，但 DOM 暴露并没有改变后者，这与 BLM 的原则一致。
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