Velez Cátia, Freitas Rosa, Antunes Sara C, Soares Amadeu M V M, Figueira Etelvina
Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro, Portugal; CESAM - Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal; CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas 289, 450-123 Porto, Portugal.
Ecotoxicol Environ Saf. 2016 Mar;125:43-54. doi: 10.1016/j.ecoenv.2015.11.030. Epub 2015 Dec 2.
To assess the environmental impact of As and Hg, bioindicator organisms such as bivalves have been used. Nevertheless, few studies have assessed the impacts of As and Hg in Ruditapes decussatus and Ruditapes philippinarum, which are native and exotic species in Europe, respectively. The main goal of the present study was to assess elements' partitioning and detoxification strategies of R. decussatus and R. philippinarum. Both clams showed a higher capacity to bioconcentrate Hg (BCF 2.29-7.49), when compared to As (0.59-1.09). Furthermore, As accumulation in both species was similar in the soluble and insoluble fractions, while in both species the majority of Hg was found in the insoluble fraction. Clams exposed to As showed different detoxification strategies, since R. decussatus had higher ability to enhance antioxidant enzymes and metallothioneins in order to reduce toxicity, and R.philippinarum increased glutathione S-transferase Ω activity, that catalyzes monomethyl arsenate reduction, the rate-limiting reaction in arsenic biotransformation. When exposed to Hg, R. decussatus presented, higher synthesis of antioxidant enzymes and lower LPO, being able to better tolerate Hg than the exotic species R. philippinarum. Thus under relevant levels of As and Hg contamination our work evidenced the higher ability of R. decussatus to survive and inhabit coastal environments not heavily contaminated by Hg and As.
为了评估砷和汞对环境的影响，人们使用了双壳贝类等生物指示生物。然而，很少有研究评估砷和汞对欧洲本地物种波纹巴非蛤和外来物种菲律宾蛤仔的影响。本研究的主要目的是评估波纹巴非蛤和菲律宾蛤仔体内元素的分配和解毒策略。与砷（生物富集系数为0.59 - 1.09）相比，两种蛤类对汞的生物富集能力更强（生物富集系数为2.29 - 7.49）。此外，两种蛤类体内砷在可溶部分和不可溶部分的积累情况相似，而两种蛤类体内的汞大部分存在于不可溶部分。暴露于砷的蛤类表现出不同的解毒策略，波纹巴非蛤增强抗氧化酶和金属硫蛋白以降低毒性的能力更强，而菲律宾蛤仔则提高了谷胱甘肽S - 转移酶Ω的活性，该酶催化单甲基砷酸盐还原，这是砷生物转化中的限速反应。暴露于汞时，波纹巴非蛤的抗氧化酶合成量更高，脂质过氧化水平更低，比外来物种菲律宾蛤仔更能耐受汞。因此，在相关水平的砷和汞污染情况下，我们的研究证明了波纹巴非蛤在未受汞和砷严重污染的沿海环境中生存和栖息的能力更强。
