Sánchez-Marín Paula, Lorenzo J Ignacio, Blust Ronny, Beiras Ricardo
Departamento de Ecoloxía e Bioloxía Animal, Fac. Ciencias do Mar, Universidade de Vigo, Crta. Colexio Universitario s/n. E-36310 Vigo, Spain.
Environ Sci Technol. 2007 Aug 15;41(16):5679-84. doi: 10.1021/es070088h.
The presence of dissolved organic matter (DOM), as humic acids (HA), in natural waters is assumed to decrease dissolved metal bioavailability by binding metal ions and, therefore, decreasing the free ion concentration in solution. In this study, Pb complexation by HA in artificial seawater was checked by means of square wave anodic stripping voltammetry (SWASV). Uptake and toxicity of this metal in the absence and presence of HA was tested using excised gills of Mytilus edulis and the Paracentrotus lividus embryo-larval bioassay respectively. Both Pb uptake by mussel gills and Pb toxicity to sea urchin larvae increased in the presence of HA, and this increase was higher at higher HA concentrations. Since it is shown that the presence of DOM can enhance the uptake and toxicity of lead in some important marine invertebrate species, these results challenge the general applicability of the free ion activity and related models used for deriving environmental water quality criteria for metals.
天然水体中溶解有机物（DOM）以腐殖酸（HA）形式存在时，被认为会通过结合金属离子降低溶解态金属的生物可利用性，从而降低溶液中游离离子的浓度。在本研究中，通过方波阳极溶出伏安法（SWASV）检测了人工海水中HA对铅的络合作用。分别使用紫贻贝的离体鳃以及地中海海胆胚胎-幼虫生物测定法，测试了在不存在和存在HA的情况下该金属的摄取和毒性。在存在HA的情况下，贻贝鳃对铅的摄取以及铅对海胆幼虫的毒性均增加，且在较高HA浓度下这种增加更为明显。由于已表明DOM的存在会增强某些重要海洋无脊椎动物物种对铅的摄取和毒性，因此这些结果对用于推导金属环境水质标准的游离离子活性及相关模型的普遍适用性提出了挑战。
