Divison for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička Cesta 54, HR-10000 Zagreb, Croatia.
Department of Geology, Faculty of Science, University of Zagreb, Horvatovac 95, HR-10000 Zagreb, Croatia.
Molecules. 2021 Nov 3;26(21):6656. doi: 10.3390/molecules26216656.
Assessing the environmental quality of coastal systems is important not only for the management and protection of such areas, but also for improving the quality of water resources. Since sediment itself can often be a source of certain toxic elements, in addition to information on the distribution of metals in the water column and in the sediment itself, it is useful to determine the bioavailable forms of individual elements, particularly toxic ones. In this study, water and sediment geochemical data were supplemented with oxyanion mobility in sediments estimated by diffusion gradients in thin film (DGTs). The data obtained indicate that the chemical composition of the water in the Raša River estuary primarily reflects the high input of suspended sediment from the catchment, the mixing of freshwater and seawater, and to a lesser extent the effects of anthropogenic activities. Although sediment composition is primarily determined by geological and hydrodynamic conditions in the catchment, it also indicates moderate enrichment in Co, Cr, Mo and Ni. In contrast, the distribution of oxyanions in sediment pore water indicates the influence of sediment as a source of some elements in the bottom water; e.g., sediment contributes to 40% of the arsenic bottom water budget. The obtained depth profiles of the oxyanion distribution in the sediment pore water indicate an early onset of suboxic to anoxic conditions in Raša Bay, which is prone to rapid sedimentation. All this demonstrates the need to consider the bioavailable forms of elements when assessing environmental quality, as the lack of such information can lead to an incomplete assessment, especially in dynamic coastal systems such as estuaries.
评估沿海系统的环境质量不仅对这些地区的管理和保护很重要，而且对提高水资源质量也很重要。由于沉积物本身通常是某些有毒元素的来源，因此除了了解金属在水柱和沉积物中的分布情况外，确定个别元素（尤其是有毒元素）的生物可利用形态也很有用。在这项研究中，水和沉积物地球化学数据补充了通过薄膜扩散梯度（DGT）估计的沉积物中含氧阴离子的迁移率。所得数据表明，Raša 河口的水化学组成主要反映了流域高悬浮泥沙的输入、淡水和海水的混合，以及人为活动的影响较小。尽管沉积物的组成主要取决于流域的地质和水动力条件，但它也表明 Co、Cr、Mo 和 Ni 有中度富集。相比之下，沉积物孔隙水中含氧阴离子的分布表明，沉积物是底水中某些元素的来源之一；例如，沉积物对砷的底水预算的贡献达到 40%。沉积物孔隙水中含氧阴离子分布的深度剖面表明，Raša 湾较早出现亚缺氧到缺氧条件，这容易导致快速沉积。所有这些都表明，在评估环境质量时需要考虑元素的生物可利用形态，因为缺乏此类信息可能会导致评估不完整，特别是在像河口这样的动态沿海系统中。
