Hi all…as this year’s cyanotoxin season draws near, a review article entitled “Toxic cyanobacteria and drinking water: Impacts, detection, and treatment” has just appeared in print. The authors state “this paper synthesizes and updates a number of previous review articles on various aspects of this multi-barrier approach in order to provide a holistic resource for researchers, water managers and engineers, as well as water treatment plant operators.” At a quick glance it looks like a good paper if you have an interest in cyanotoxins.

Bill

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Toxic cyanobacteria and drinking water: Impacts, detection, and treatment

Xuexiang He, Yen-Ling Liu, Amanda Conklin, Judy Westrick, Linda K. Weavers, Dionysios D. Dionysiou, John J. Lenhart, Paula J. Mouser, David Szlag, Harold W. Walker

Harmful Algae Volume 54, April 2016, Pages 174–193

http://www.sciencedirect.com/science/article/pii/S1568988316300038

Abstract

“Blooms of toxic cyanobacteria in water supply systems are a global issue affecting water supplies on every major continent except Antarctica. The occurrence of toxic cyanobacteria in freshwater is increasing in both frequency and distribution. The protection of water supplies has therefore become increasingly more challenging. To reduce the risk from toxic cyanobacterial blooms in drinking water, a multi-barrier approach is needed, consisting of prevention, source control, treatment optimization, and monitoring. In this paper, current research on some of the critical elements of this multi-barrier approach are reviewed and synthesized, with an emphasis on the effectiveness of water treatment technologies for removing cyanobacteria and related toxic compounds. This paper synthesizes and updates a number of previous review articles on various aspects of this multi-barrier approach in order to provide a holistic resource for researchers, water managers and engineers, as well as water treatment plant operators.”

Conclusions

  1. “While much is known about the toxicity of microcystins, significantly less information is available regarding the toxicity of other cyanotoxins…
  2. Direct methods for detecting and quantifying cyanotoxins in drinking water… are expensive and require extensive expertise. Indirect methods are valuable as a pre-screening tool but may not accurately represent cyanotoxin concentrations under some conditions…
  3. …both disinfection with chlorine and activated carbon adsorption can be modified to enhance the removal of either toxic cyanobacterial cells and/or cyanotoxins. Disinfection may result in the destruction of cyanotoxins, but generally requires a ‘‘CT’’ value higher than typically used for other treatmentobjectives. Also, one single disinfectant will not be effective for all cyanotoxins…While activated carbon can be effective, the dosages needed may be higher than for other treatment objectives (such as for T&O compounds) and the type of carbon used may be different.
  4. Microbes capable of degrading microcystin compounds are known and have shown varying degrees of success in the lab and at the field-scale reducing cyanotoxin concentrations during drinking water treatment…
  5. Reverse osmosis and tight nanofiltration membranes are effective for most cyanotoxins…While ultrafiltration and microfiltration are not capable of removing cyanotoxins via size exclusion, research is exploring how this technology can be coupled to adsorption for effective removal of both toxins and cyanobacterial cells.
  6. Advanced oxidation processes, including ultrasound, UV, UV/ H2O2, and ozone show promise for the destruction of cyanobacterial cells and/or cyanotoxins in drinking water….”