Department of Limnology and Bio-Oceanography, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria.
Department of Chemistry, Maseno University, P.O. Box 333, Maseno, 40105, Kenya.
Arch Environ Contam Toxicol. 2020 May;78(4):589-603. doi: 10.1007/s00244-020-00715-0. Epub 2020 Feb 4.
This is the first comprehensive report on the accumulation of Cr, Ni, As, and Ag in the fish species Nile tilapia Oreochromis niloticus and Nile perch Lates niloticus from Lake Victoria, complemented with recent data on Cu, Zn, Cd, and Pb. This also is the first report on Cr, Ni, As, and Ag levels in invertebrates: the shrimp Caridina nilotica, gastropod Pila ovata, and bivalve Mutela bourguignati. The study was conducted at five sites in the Kenyan part of Lake Victoria: four sites in Winam Gulf influenced by various anthropogenic pressures, including a site near Kisumu City, and one in the main lake, with lesser direct anthropogenic influence. Apart from Cu and Ag, which were highest in O. niloticus liver, the invertebrates had higher levels of trace elements than fish. Contamination of the gulf with trace elements was best mirrored by the invertebrates, whose mobility is limited; they accumulated Cr, Cd, Ag, and Pb corresponding to the levels in the surface sediment. The accumulation of trace elements in fish species and their bioindicative potential corresponded to their habitats and feeding behaviour. The tissue contents of most trace elements were higher in the inshore-dwelling, omnivorous O. niloticus compared to the pelagic, piscivorous L. niloticus. Cu (465 ± 689 mg/kg dw) and Ag (3.45 ± 1.49 mg/kg dw) in the liver of O. niloticus were up to 10 and 119 times higher than in L. niloticus, respectively. Oreochromis niloticus therefore has bioindicative potential for Cu and Ag contamination. Both the invertebrates and fish showed positive correlations between Cu and Ag concentrations, indicating similar source and/or uptake route. The target hazard quotients (THQ) show that there is no human health risk associated with the consumption of these fish. However, the levels of Zn, Cd, and Pb in P. ovata surpassed maximum food safety limits and are hence potentially unsafe for human consumption.
这是第一篇关于维多利亚湖尼罗罗非鱼和尼罗河鲈鱼中 Cr、Ni、As 和 Ag 积累的综合报告，补充了最近关于 Cu、Zn、Cd 和 Pb 的数据。这也是关于无脊椎动物 Cr、Ni、As 和 Ag 水平的第一篇报告：虾 Caridina nilotica、腹足纲 Pila ovata 和双壳纲 Mutela bourguignati。该研究在维多利亚湖肯尼亚部分的五个地点进行：温亚马湾的四个地点受到各种人为压力的影响，包括基苏木市附近的一个地点和一个主要湖泊的一个地点，人为影响较小。除了 Cu 和 Ag 在罗非鱼肝脏中含量最高外，无脊椎动物的痕量元素含量高于鱼类。无脊椎动物反映了海湾的痕量元素污染最好，因为它们的移动性有限；它们积累的 Cr、Cd、Ag 和 Pb 与表层沉积物中的水平相对应。鱼类中痕量元素的积累及其生物指示潜力与其栖息地和摄食行为相对应。大多数痕量元素的组织含量在近海栖息的杂食性 O. niloticus 中高于远洋掠食性 L. niloticus。O. niloticus 肝脏中的 Cu（465±689 mg/kg dw）和 Ag（3.45±1.49 mg/kg dw）分别比 L. niloticus 高 10 倍和 119 倍。因此，O. niloticus 具有 Cu 和 Ag 污染的生物指示潜力。无脊椎动物和鱼类的 Cu 和 Ag 浓度之间呈正相关，表明具有相似的来源和/或吸收途径。目标危害商数 (THQ) 表明，食用这些鱼类不存在与人类健康相关的风险。然而，P. ovata 中的 Zn、Cd 和 Pb 水平超过了最大食品安全限值，因此对人类食用可能不安全。
