A Global Analysis of the Relationship between Concentrations of Microcystins in Water and Fish

Abstract

Cyanobacteria, the primary bloom-forming organisms in fresh water, elicit a spectrum of problems in lentic systems. The most immediate concern for people and animals are cyanobacterial toxins, which have been detected at variable concentrations in water and fish around the world. Cyanotoxins can transfer through food webs, potentially increasing the risk of exposure to people who eat fish from affected waters, yet little is known about how cyanotoxins fluctuate in wild fish tissues. We collated existing studies on cyanotoxins in fish and fresh water from lakes around the world into a global dataset to test the hypothesis that cyanotoxin concentrations in fish increase with water toxin concentrations. We limited our quantitative analysis to microcystins because data on other cyanotoxins in fish were sparse, but we provided a qualitative summary of other cyanotoxins reported in wild, freshwater fish tissues. We found a positive relationship between intracellular microcystin in water samples and microcystin in fish tissues that had been analyzed by assay methods (enzyme-linked immunosorbent assay and protein phosphatase inhibition assay). We expected microcystin to be found in increasingly higher concentrations from carnivorous to omnivorous to planktivorous fishes. We found, however, that omnivores generally had the highest tissue microcystin concentrations. Additionally, we found contrasting results for the level of microcystin in different tissue types depending on the toxin analysis method. Because microcystin and other cyanotoxins have the potential to impact public health, our results underline the current need for comprehensive and uniform detection methods for the analysis of cyanotoxins in complex matrices.

Response of Fish Gut Microbiota to Toxin-Containing Cyanobacterial Extracts: A Microcosm Study on the Medaka (Oryzias latipes)

“…In recent years, massive cyanobacterial blooms increased in frequency and persistence around the world, causing serious threats to aquatic ecosystems 1,2 . Indeed, cyanobacteria produce numerous bio-active secondary metabolites, including various cyanotoxins, that remain and bioaccumulate into the environment, especially after bloom senescence [3][4][5] . The most widespread cyanotoxin is microcystin-leucinearginine (MC-LR) which can accumulate in the liver of aquatic vertebrates including fish 6,7 .…”

Review of current state of knowledge of microcystin and its impacts on fish in Lake Victoria

“…The toxin levels usually build up along the food chain. Nevertheless, there is inadequate knowledge on toxin biomagnification(Flores, Miller, & Stockwell, 2018;Kozlowsky-Suzuki et al, 2012). Although recent studies have proved fish and human accumulation of toxins is associated with the environmental concentration of particular toxins, coupled with the exposure period(Gurbuz, Uzunmehmetoglu, Diler, Metcalf, & Codd, 2016;Jia et al, 2014), the MCs concentration up the trophic level is limited because of toxin depuration(Ferrao-Filho and Kozlowsky-Suzuki, 2011;Zhang et al 2009).…”

Nuevas metodologías para el análisis de microcistinas en peces. Estudio de Astraloheros Facetus expuestos in vitro.

“…Los inmunoensayos del tipo ELISA son sencillos, rápidos, no requieren equipamiento costoso, permiten detectar MC-LR y presentan alta reactividad cruzada con las variantes más frecuentes, por lo que son altamente utilizados como metodologías de monitoreo. Sin embargo, los inmunoensayos brindan una respuesta global sin identificar las variantes químicas presentes y pueden presentar problemas de efecto matriz, especialmente en matrices biológicas complejas (Flores, et al, 2018;Font, 2016). Por estas razones, además de su comparación con métodos analíticos de alta performance se requiere una cuidadosa evaluación de su desempeño en matrices biológicas.…”

“…La elevada diversidad estructural de estas cianotoxinas implica la necesidad de utilizar métodos analíticos selectivos de alta performance, como la cromatografía líquida acoplada a espectrometría de masas en tándem (LC-MS/MS), que son de muy alto costo y complejidad (Meriluoto, et al, 2017;Flores, et al, 2018). Adicionalmente para la cuantificación se necesitan estándares de todas estas variantes químicas, de las cuales la mayoría no están disponibles comercialmente.…”