Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Av. Ciudad Universitaria 3000, C.P. 04510, Coyoacán, Ciudad de México, Mexico.
Laboratory of Aquatic Zoology, Division of Research and Postgraduate Studies, National Autonomous University of Mexico, Campus Iztacala, Av. de Los Barrios No. 1, C.P. 54090, Los Reyes, Tlalnepantla, State of Mexico, Mexico.
Environ Pollut. 2019 Jun;249:267-276. doi: 10.1016/j.envpol.2019.03.029. Epub 2019 Mar 11.
Cyanotoxins from toxic blooms in lakes or eutrophic reservoirs are harmful to several organisms including zooplankton, which often act as vectors of these secondary metabolites, because they consume cyanobacteria, bioaccumulate the cyanotoxins and pass them on along the food chain. Microcystins are among the most commonly found cyanotoxins and often cause zooplankton mortality. Although cyanobacterial blooms are common and persistent in Mexican water bodies, information on the bioaccumulation of cyanotoxins is scarce. In this study we present data on the bioaccumulation of cyanotoxins from Planktothrix agardhii, Microcystis sp., Cylindrospermopsis raciborskii and Dolichospermum planctonicum blooms in the seston (suspended particulate matter more than 1.2 μm) by zooplankton and fish (tilapia (Oreochromis niloticus) and mesa silverside (Chirostoma jordani) samples from Lake Zumpango (Mexico City). The cyanotoxins were extracted from the seston, zooplankton and fish tissue by disintegration using mechanical homogenization and 75% methanol. After extraction, microcystins were measured using an ELISA kit (Envirologix). Concentration of microcystins expressed as equivalents, reached a maximum value of 117 μg g on sestonic samples; in zooplankton they were in the range of 0.0070-0.29 μg g. The dominant zooplankton taxa included Acanthocyclops americanus copepodites, Daphnia laevis and Bosmina longirostris. Our results indicate twice the permissible limits of microcystins (0.04 μg kg d) for consumption of cyanobacterial products in whole fish tissue of Chirostoma jordani. The data have been discussed with emphasis on the importance of regular monitoring of water bodies in Mexico to test the ecotoxicological impacts of cyanobacterial blooms and the risk that consumption of products with microcystins could promote.
湖泊或富营养化水库中的有毒水华产生的蓝藻毒素对包括浮游动物在内的多种生物都具有危害性，浮游动物常常作为这些次生代谢物的载体，因为它们会摄食蓝藻，生物累积蓝藻毒素并沿食物链传递。微囊藻毒素是最常见的蓝藻毒素之一，常常导致浮游动物死亡。虽然蓝藻水华在墨西哥水体中很常见且持续存在，但有关蓝藻毒素生物累积的信息却很匮乏。在本研究中，我们提供了浮游动物和鱼类（罗非鱼（Oreochromis niloticus）和棋盘银汉鱼（Chirostoma jordani）样本）通过摄食哲水蚤（悬浮在大于 1.2 μm 的颗粒物质中）、微囊藻、铜绿微囊藻和席藻水华体内的蓝藻毒素的生物累积数据，这些水华均来自于萨波特克湖（墨西哥城）。通过机械匀浆和 75%甲醇使哲水蚤、浮游动物和鱼类组织解体来提取蓝藻毒素。提取后，使用 ELISA 试剂盒（Envirologix）来测量微囊藻毒素。以微囊藻毒素当量表示的浓度，在哲水蚤样本中达到了 117 μg g 的最大值；在浮游动物中，浓度范围为 0.0070-0.29 μg g。主要的浮游动物类群包括桡足类的剑水蚤无节幼体、大型溞和长刺溞。我们的结果表明，棋盘银汉鱼整个鱼组织中的微囊藻毒素含量是可食用蓝藻产品的允许限量（0.04 μg kg d）的两倍。我们的数据已经过讨论，重点是强调对墨西哥水体进行定期监测的重要性，以测试蓝藻水华的生态毒理学影响以及食用含有微囊藻毒素的产品可能带来的风险。
