There is a global concern regarding the increase of cyanotoxins in freshwater and their potential effects on human health. The existence of multiple toxins in freshwater can result in an increased risk of their bioaccumulation in humans from their ingestion through contaminated drinking water or recreational activities. This study, the first of its kind, was conducted to determine the occurrence of thirteen cyanotoxins namely; microcystins (-LA, -LF, -LR, -LY, -LW, -RR, -YR, -WR, dm MC-RR and dm MC-LR), anatoxin-a, nodularin and cylindrospermopsin in the freshwaters of Lake Victoria in Tanzania. A total of 23 sites were selected for water sampling. Samples were randomly collected from lakeshores (n = 54), wells (n = 66) and piped water (n = 18) in two phases, February (dry season) and December (rainy season) 2018. Samples (n = 138) were analysed using liquid chromatography mass spectrometry (UPLC-MS/MS). Cylindrospermopsin was the most abundant cyanotoxin detected in the lakeshores, with eight of the nine collection sites (89%) reporting cylindrospermopsin in phase I, compared to three out of nine (33%) in phase II. Microcystin congeners -RR, -LR and -YR were detected in phase I, with microcystins -RR and -LR detected in phase II. MC concentrations ranged from 0.003 to 0.007 μg/L for MC-RR, 0.01–0.013 μg/L for MC-LR and 0.004 to 0.01 μg/L for cylindrospermopsin, with nodularin reported once at a concentration of 0.01 μg/L. No cyanotoxins were detected in wells or in treated pipe water samples. The existence of multiple toxins in different collection sites may lead to synergistic effects and increase the toxicological risk to humans. This is the first study to report the presence of cylindrospermopsin and nodularin in the freshwaters of Lake Victoria.

全球关注的是淡水中氰毒素的增加及其对人体健康的潜在影响。淡水中多种毒素的存在会导致饮用水中污染物的摄取或娱乐活动增加其在人体中的生物蓄积风险。这项研究是同类研究中的第一项，旨在确定十三种氰毒素的存在。维多利亚湖淡水中的微囊藻毒素（-LA，-LF，-LR，-LY，-LW，-RR，-YR，-WR，dm MC-RR和dm MC-LR），抗毒素a，结瘤素和环精胺在坦桑尼亚。总共选择了23个地点进行水采样。从湖岸（n  = 54），水井（n  = 66）和自来水（n = 18）分为两个阶段，即2018年2月（旱季）和12月（雨季）。样本（n ＝ 138）用液相色谱质谱法（UPLC-MS / MS）分析。Cylindrospermopsin是湖岸中检测到的最丰富的氰毒素，九个收集地点中的八个报告了第一阶段的cylindrospermopsin，而第二阶段的九个收集地点中有三个（33％）。在第一阶段检测到微囊藻毒素同源物-RR，-LR和-YR，在第二阶段检测到微囊藻毒素-RR和-LR。MC-RR的MC浓度范围为0.003至0.007μg/ L，MC-LR的MC浓度范围为0.01–0.013μg/ L，而cysdrodrospermopsin的浓度范围为0.004至0.01μg/ L，据报道一次结节霉素的浓度为0.01μg/ L。在井中或经处理的管道水样品中均未检测到氰毒素。在不同收集位点存在多种毒素可能导致协同效应，并增加对人类的毒理学风险。