Microcystins in potable surface waters: toxic effects and removal strategies

Abstract

In freshwater, harmful cyanobacterial blooms threaten to increase with global climate change and eutrophication of surface waters. In addition to the burden and necessity of removal of algal material during water treatment processes, bloom-forming cyanobacteria can produce a class of remarkably stable toxins, microcystins, difficult to remove from drinking water sources. A number of animal intoxications over the past 20 years have served as sentinels for widespread risk presented by microcystins. Cyanobacterial blooms have the potential to threaten severely both public health and the regional economy of affected communities, particularly those with limited infrastructure or resources. Our main objectives were to assess whether existing water treatment infrastructure provides sufficient protection against microcystin exposure, identify available options feasible to implement in resource-limited communities in bloom scenarios and to identify strategies for improved solutions. Finally, interventions at the watershed level aimed at bloom prevention and risk reduction for entry into potable water sources were outlined. We evaluated primary studies, reviews and reports for treatment options for microcystins in surface waters, potable water sources and treatment plants. Because of the difficulty of removal of microcystins, prevention is ideal; once in the public water supply, the coarse removal of cyanobacterial cells combined with secondary carbon filtration of dissolved toxins currently provides the greatest potential for protection of public health. Options for point of use filtration must be optimized to provide affordable and adequate protection for affected communities.

Regulation of Microcystin-LR-Induced Toxicity in Mouse Spermatogonia by miR-96

“…Furthermore, this concentration has not only been used in the literature by others, 30,31 but also is relevant for environmental accumulation of MC in the lake water with blue algae blooms where the concentration of MC may range from as low as less than 20 nM to more than 100 μM as reported. 32 Interestingly, of the 25 miRNAs, the expression of miR-34, miR-122 and miR-181a was found to be modulated in the semen samples from infertile patients in a previous study. 33 However, the origins of these miRNA in semen are still unclear.…”

Microcystins Alter Chemotactic Behavior in Caenorhabditis elegans by Selectively Targeting the AWA Sensory Neuron

“…Total MCs exceeding 2000 µg/L have been detected in surface water bodies, and these levels are associated with toxicity [70]. The concentrations of MCs, tautomycin and okadaic acid taken up by C. elegans neurons in this study are unknown, as are the metabolism, distribution and excretion rates of these PP inhibitors once taken up by the worm.…”

Cyanobacterial water bloom of Limnoraphis robusta in the Lago Mayor of Lake Titicaca. Can it develop?

“…Much attention is paid to cyanobacterial water blooms because of their dangerous toxicity, their mass production often evoking anoxia connected with adverse impacts upon fish stocks and basic changes in water quality. Problems associated with toxins (which can be present both in the biomass and water) are especially important when the water body is used as a source of drinking water (Chorus & Bartram, 1999;Roegner et al, 2014).…”