Velez Cátia, Galvão Petrus, Longo Renan, Malm Olaf, Soares Amadeu M V M, Figueira Etelvina, Freitas Rosa
Departamento de Biologia & CESAM, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
Environ Sci Pollut Res Int. 2015 Aug;22(15):11890-904. doi: 10.1007/s11356-015-4397-7. Epub 2015 Apr 14.
The native species Ruditapes decussatus and the invasive species Ruditapes philippinarum have an important ecological role and socio-economic value, from the Atlantic and Mediterranean to the Indo-Pacific region. In the aquatic environment, they are subjected to the presence of different contaminants, such as mercury (Hg) and its methylated form, methylmercury (MeHg). However, few studies have assessed the impacts of Hg on bivalves under environmental conditions, and little is known on bivalve oxidative stress patterns due to Hg contamination. Therefore, this study aims to assess the Hg contamination in sediments as well as the concentration of Hg and MeHg in R. decussatus and R. philippinarum, and to identify the detoxification strategies of both species living in sympatry, in an aquatic system with historical Hg contamination. The risk to human health due to the consumption of clams was also evaluated. The results obtained demonstrated that total Hg concentration found in sediments from the most contaminated area was higher than the maximum levels established by Sediment Quality Guidelines. This study further revealed that the total Hg and MeHg accumulation in both species was strongly correlated with the total Hg contamination of the sediments. Nonetheless, the THg concentration in both species was lower than maximum permissible limits (MPLs) of THg defined by international organizations. R. decussatus and R. philippinarum showed an increase in lipid peroxidation levels along with the increase of THg accumulation by clams. Nevertheless, for both species, no clear trend was obtained regarding the activity of antioxidant (superoxide dismutase, catalase) and biotransformation (glutathione S-transferase) enzymes and metallothioneins with the increase of THg in clams. Overall, the present work demonstrated that both species can be used as sentinel species of contamination and that the consumption of these clams does not constitute a risk for human health.
本地物种波纹巴非蛤和入侵物种菲律宾蛤仔在从大西洋和地中海到印度 - 太平洋地区都具有重要的生态作用和社会经济价值。在水生环境中，它们会接触到不同的污染物，如汞（Hg）及其甲基化形式甲基汞（MeHg）。然而，很少有研究评估环境条件下汞对双壳贝类的影响，对于汞污染导致的双壳贝类氧化应激模式也知之甚少。因此，本研究旨在评估沉积物中的汞污染以及波纹巴非蛤和菲律宾蛤仔体内汞和甲基汞的浓度，并确定在一个存在历史汞污染的水生系统中，这两种同域分布物种的解毒策略。还评估了食用蛤仔对人类健康的风险。所得结果表明，受污染最严重地区沉积物中的总汞浓度高于沉积物质量指南规定的最高水平。本研究进一步揭示，这两种物种体内总汞和甲基汞的积累与沉积物中的总汞污染密切相关。尽管如此，这两种物种体内的总汞浓度均低于国际组织定义的总汞最大允许限量（MPLs）。随着蛤仔体内总汞积累的增加，波纹巴非蛤和菲律宾蛤仔的脂质过氧化水平有所上升。然而，对于这两种物种，随着蛤仔体内总汞含量的增加，抗氧化酶（超氧化物歧化酶、过氧化氢酶）和生物转化酶（谷胱甘肽S - 转移酶）以及金属硫蛋白的活性并未呈现出明显趋势。总体而言，目前的研究表明这两种物种都可作为污染的指示物种，并且食用这些蛤仔对人类健康不构成风险。
