Laboratory of Analysis, Treatment and Valorization of Pollutants of the Environment and Products, Faculty of Pharmacy, University of Monastir, Ibn Sina Street, 5000, Monastir, Tunisia.
University Côte d'Azur, CNRS, ECOSEAS, UMR 7035, 28 Avenue Valrose BP 71, 06108, Nice Cedex 2, France.
Arch Environ Contam Toxicol. 2020 Apr;78(3):478-494. doi: 10.1007/s00244-020-00713-2. Epub 2020 Feb 3.
In the present study, a multi-biomarker approach was used to assess the biological effects of metal pollution in the southern lagoon of Tunis, on clam Ruditapes decussatus both in "hot" (in summer) and "cold" (in winter) seasons. Clams were collected in August 2015 and February 2016 from three sites of the lagoon and from Louza considered a reference site. The concentrations of five trace metals (cadmium, copper, iron, lead, and zinc) in the soft tissues of R. decussatus were evaluated at the sampling sites. A core of biomarkers indicative of (a) neurotoxicity (acetylcholinesterase, AChE); (b) biotransformation (glutathione S-transferase, GST); (c) oxidative stress (catalase, CAT; total glutathione peroxidase, T-GPx; total glutathione peroxidase, T-GPx; selenium-dependent glutathione peroxidase, Se-GPx; glutathione reductase, GR; superoxide dismutase, SOD) (d) lipid peroxidation (malondialdhyde, MDA level), and (e) apoptotic process (caspase 3-like, CSP3) was selected for measurements of environmental effects on the populations of clams collected from the different sampling sites. The results of metal bioaccumulation in soft tissues of Ruditapes decussatus revealed a high pollution in the South Lagoon of Tunis with spatial variation and relatively high levels at the navigation channel. Anthropogenic pollutants in the lagoon led to the activation of antioxidant defense and biotransformation enzymes to oxidative damage of the membrane and activation of apoptosis, and revealed neurotoxicity. Among this core of biomarkers, the antioxidants enzymes (CAT, SOD, GR, and GPx) were very sensitive, allowing the discrimination among sites and pointing to the navigation channel as the most impacted site in the southern lagoon of Tunis. Moreover, a significant effect of season was recorded on biomarkers responses (e.g., CAT, GR, SOD, AChE, and CSP3 activities and MDA levels) with higher levels in winter than in summer, probably influenced by the reproductive stage and food availability. Finally, the measurement of the selected core of biomarkers in the whole soft tissues of clams was considered as an integrated indicator of environmental stress. Moreover, R. decussatus proved to be a remarkable sentinel species capable to establish a reliable diagnosis of the health status of the marine environment in different areas of the southern lagoon of Tunis, both in "hot" and "cold" seasons.
在本研究中，采用多生物标志物方法评估了金属污染对突尼斯南部泻湖贻贝（Ruditapes decussatus）的生物学影响，研究对象为夏季（热季）和冬季（冷季）的贻贝。2015 年 8 月和 2016 年 2 月，从泻湖的三个地点和 Louza（一个参考地点）采集了贻贝样本。评估了贻贝软体组织中五种痕量金属（镉、铜、铁、铅和锌）的浓度。选择了一组生物标志物来评估环境对贻贝种群的影响，这些生物标志物包括：（a）神经毒性（乙酰胆碱酯酶，AChE）；（b）生物转化（谷胱甘肽 S-转移酶，GST）；（c）氧化应激（过氧化氢酶，CAT；总谷胱甘肽过氧化物酶，T-GPx；硒依赖性谷胱甘肽过氧化物酶，Se-GPx；谷胱甘肽还原酶，GR；超氧化物歧化酶，SOD）；（d）脂质过氧化（丙二醛，MDA 水平）；（e）细胞凋亡过程（半胱天冬酶 3 样，CSP3）。贻贝软体组织中金属的生物积累结果表明，突尼斯南部泻湖污染严重，存在空间变异，航道处的污染水平相对较高。泻湖中人为污染物导致抗氧化防御和生物转化酶被激活，以应对膜的氧化损伤和细胞凋亡的激活，并显示出神经毒性。在这组核心生物标志物中，抗氧化酶（CAT、SOD、GR 和 GPx）非常敏感，能够区分不同的地点，并指出航道是突尼斯南部泻湖中受影响最严重的地点。此外，季节对生物标志物的反应有显著影响（例如，CAT、GR、SOD、AChE 和 CSP3 活性和 MDA 水平），冬季的水平高于夏季，这可能受到繁殖阶段和食物供应的影响。最后，测量贻贝整个软体组织中选定的核心生物标志物被认为是环境应激的综合指标。此外，Ruditapes decussatus 被证明是一种非常有价值的指示物种，能够对突尼斯南部泻湖不同地区的海洋环境健康状况进行可靠诊断，无论是在热季还是冷季。
