减轻暴露于淡水有害藻华(HAB)带来的健康风险的可用指导很大程度上来自温带生态系统。然而在热带生态系统中,HAB可以全年发生,依赖资源的人群面临多种接触有毒成分的途径。沿着Winam海湾,维多利亚湖,肯尼亚,渔民社区依靠被HAB的微囊藻毒素(MC)污染的湖水。在基苏木附近的城郊社区,我们测试了MC跨季节超过暴露指南的假设,和持续性HABs通过摄入最少的水处理和频繁的水处理,对渔民社区带来慢性风险,直接接触。从2015年9月到2016年5月,我们在干旱和雨季的11个社区测试了水源水。我们测量了MC,其他代谢物,物理化学参数,叶绿素a,浮游植物的丰度和多样性,和粪便指标。然后我们选择了四个社区进行关于水源的采访,用法,和治疗。超过30%的水源水样本超过了世界卫生组织的MCs饮用水指南(1μg/L),超过60%的水源水样本超过了USEPA针对儿童和免疫功能低下者的指南。50%的家庭报告仅使用原始湖水饮用和家庭使用,与替代来源,包括雨和钻孔。家庭氯化是使用最广泛的处理。在这个热带,富营养化湖泊,在资源有限的环境中,HAB对渔民社区构成全年健康风险。基苏木湾和类似受影响地区需要基于社区的解决方案和针对特定地点的指导,以解决慢性健康暴露可能随着全球气候变化的严重程度和持续时间而增加的问题。
Available guidance to mitigate health risks from exposure to freshwater harmful algal blooms (HABs) is largely derived from temperate ecosystems. Yet in tropical ecosystems, HABs can occur year-round, and resource-dependent populations face multiple routes of exposure to toxic components. Along Winam Gulf, Lake Victoria, Kenya, fisher communities rely on lake water contaminated with microcystins (MCs) from HABs. In these peri-urban communities near Kisumu, we tested hypotheses that MCs exceed exposure guidelines across seasons, and persistent HABs present a chronic risk to fisher communities through ingestion with minimal water treatment and frequent, direct contact. We tested source waters at eleven communities across dry and rainy seasons from September 2015 through May 2016. We measured MCs, other metabolites, physicochemical parameters, chlorophyll a, phytoplankton abundance and diversity, and fecal indicators. We then selected four communities for interviews about water sources, usage, and treatment. Greater than 30% of source water samples exceeded WHO drinking water guidelines for MCs (1μg/L), and over 60% of source water samples exceeded USEPA guidelines for children and immunocompromised individuals. 50% of households reported sole use of raw lake water for drinking and household use, with alternate sources including rain and boreholes. Household chlorination was the most widespread treatment utilized. At this tropical, eutrophic lake, HABs pose a year-round health risk for fisher communities in resource -limited settings. Community-based solutions and site-specific guidance for Kisumu Bay and similarly impacted regions is needed to address a chronic health exposure likely to increase in severity and duration with global climate change.