Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička c. 54, 10000, Zagreb, Croatia.
Environ Geochem Health. 2018 Feb;40(1):489-503. doi: 10.1007/s10653-017-9935-4. Epub 2017 Mar 14.
On small and medium karstic coastal islands in the Adriatic Sea, brackish lakes are often the only source of freshwater. Therefore, it is important to adequately evaluate the biogeochemical processes occurring in these complex water systems, as well as to determine the origin of contaminants present. In this study, the distribution and origin of trace metals (Tl, Hg, Cd, Pb, Cu, Zn, Ni, Co) and organic matter in the water column, sediment, and surrounding soil of the brackish lakes on Mljet Island, South Adriatic Sea, Croatia, were evaluated. Thallium and mercury concentrations in the lake water were up to two orders of magnitude higher compared to ranges found in the adjacent coastal sea water. Elevated thallium concentrations were of anthropogenic origin resulting from previous use of rodenticide, while elevated mercury content was naturally enhanced. Levels for the other metals were characteristic of uncontaminated water systems. Speciation modelling showed that dissolved trace metals such as Cu, Pb, and Zn were mostly associated with organic matter, while Tl, Co, and Ni were present predominantly as free ions and inorganic complexes. The presence of organic matter (OM) clearly influenced the speciation and distribution of some trace metals. OM was characterised by the determination of the complexing capacity for Cu ions (CuCC), surface active substances, and catalytically active compounds. Reduced sulphur species (glutathione and other thiols) representing significant Cu-binding ligands were determined and discussed as well.
在地中海亚得里亚海的小型和中型岩溶沿海岛屿上，微咸水湖通常是唯一的淡水来源。因此，充分评估这些复杂水系中发生的生物地球化学过程以及确定存在污染物的来源非常重要。在这项研究中，评估了克罗地亚亚得里亚海南部 Mljet 岛上微咸水湖中水柱、沉积物和周围土壤中痕量金属（Tl、Hg、Cd、Pb、Cu、Zn、Ni、Co）和有机物的分布和来源。与相邻沿海海水中发现的范围相比，湖水的铊和汞浓度高达两个数量级。铊浓度升高是人为的，是由于先前使用灭鼠剂造成的，而汞含量升高则是自然增强的。其他金属的水平是无污染水系统的特征。形态建模表明，溶解的痕量金属（如 Cu、Pb 和 Zn）主要与有机物有关，而 Tl、Co 和 Ni 主要以游离离子和无机络合物存在。有机物（OM）的存在明显影响了一些痕量金属的形态和分布。通过测定铜离子的络合能力（CuCC）、表面活性剂和催化活性化合物来表征有机物。还确定并讨论了代表重要 Cu 结合配体的还原硫物种（谷胱甘肽和其他硫醇）。
