胶州湾海水中悬浮颗粒对溶解态微量元素的影响

Effect of the suspended particulate materials on the dissolved trace elements in Jiaozhou bay

运用离子色谱离线螯合结合ICP-MS的方法,对胶州湾海水中的微量元素(V,Co,Ni,Cu,Mo,Cd,Pb,U,REEs)进行了精确的定量分析。在测试前对在同一站位不同层位采集的平行海水样品进行了两种不同的酸化处理:一份采取先过滤后酸化的方式,以获得海水中溶解态微量元素的含量;另一份采取直接酸化后分析的方式,以评估悬浮颗粒中的可交换态微量元素对溶解态微量元素测定结果可能造成的影响。通过对比研究发现,不同处理方法得到的V、Ni、Cu、Co、Pb以及稀土元素(REEs)的质量浓度存在很大差异,说明悬浮颗粒物质可能对海水中相应元素的测定产生较大的影响。各种微量元素之间的差异和相应离子或离子团的电荷性质、在海水中的配位作用以及悬浮颗粒物质的表面电荷性质有关。初步研究结果表明,在类似于胶州湾这样的近海海域,悬浮颗粒物质是控制微量元素分布特征的一个重要因素。

An off line chelation system combined with ICP-MS technique was employed for quantitative determination of trace elements, namely V, Co, Ni, Cu, Mo, Cd, Pb, U and rare earth elements（REEs） in seawater of Jiaozhou Bay. Two different pretreatments were involved to treat the parallel seawater samples from different depths at the same site, one is acidified the sample after filtering with a 0.45 μm filter, the other is acidified the sample with ultra pure nitric acid directly. Thus the effect of suspended particulate materials on the dissolved trace elements was evaluated. We have found that there are great differences in the concentrations of V, Ni, Cu, Co, Pb and REEs between the same seawater samples that were treated by different pretreatments, which indicate that the suspended particulate materials have a great effect on the analysis of those trace elements in seawater. The differences were caused by the different electric characters, coordination chemistry of the ion or ionic group and the surface charge character of the suspended particulate materials. The primary study indicates that the suspended particulate materials are one of the most important factors that control the distribution of the trace elements in seawater.