Impact of Hydrogen Peroxide and Copper Sulfate on the Delayed Release of Microcystin
Open Access
- 13 April 2020
- Vol. 12 (4), 1105
- https://doi.org/10.3390/w12041105
Abstract
Algicides, like hydrogen peroxide and copper sulfate, are commonly applied to recreational waters and drinking water sources to mitigate cyanobacterial blooms. In this work, the effects of hydrogen peroxide and copper sulfate were evaluated in two natural bloom samples (collected from Canadian and American waterbodies) and one lab-cultured Microcystis aeruginosa suspended in Colorado River water. Five algicide to dissolved organic carbon (DOC) dose ratios were evaluated during an initial exposure period of 24 h. One dose ratio (0.4 H2O2:DOC or 0.25 CuSO4:DOC) was then evaluated during stagnation after quenching (hydrogen peroxide) or extended exposure (copper sulfate) for up to 96 or 168 h. During the initial hydrogen peroxide exposure, the CA bloom had no release of intracellular microcystins (MCs) and the USA bloom only released MC at 4 H2O2:DOC. The reverse occurred with copper sulfate, where the CA bloom released MCs at 0.6 CuSO4:DOC but the USA bloom had no detectable extracellular MCs. Extracellular MC was released from the lab-cultured Microcystis at the lowest hydrogen peroxide and copper sulfate doses. In the hydrogen peroxide stagnation experiment, intracellular MC decreased in the USA bloom after 168 h despite the low dose applied. Similarly, the extended copper sulfate exposure led to intracellular MC decreases in both bloom samples after 168 h, despite showing no impact during the initial 24 h monitoring period. The lab-cultured Microcystis was again less resistant to both algicides, with releases observed after less than 2 h of stagnation or exposure. The damage to cells as measured by pigments during these experiments did not match the MC data, indicating that blooms with depressed pigment levels can still be a risk to nearby drinking water sources or recreational activities. These results provide insight on the timeline (up to one week) required for monitoring the potential release of MCs after algicide application.This publication has 36 references indexed in Scilit:
- Diagnosing water treatment critical control points for cyanobacterial removal: Exploring benefits of combined microscopy, next-generation sequencing, and cell integrity methodsWater Research, 2019
- Cyanobacterial bloomsNature Reviews Microbiology, 2018
- Multihapten Approach Leading to a Sensitive ELISA with Broad Cross-Reactivity to Microcystins and NodularinEnvironmental Science & Technology, 2014
- A review of current knowledge on toxic benthic freshwater cyanobacteria – Ecology, toxin production and risk managementWater Research, 2013
- Toxin-producing cyanobacteria in freshwater: A review of the problems, impact on drinking water safety, and efforts for protecting public healthJournal of Microbiology, 2013
- Harmful Cyanobacterial Blooms: Causes, Consequences, and ControlsMicrobial Ecology, 2013
- Eco-physiological adaptations that favour freshwater cyanobacteria in a changing climateWater Research, 2012
- Climate change: Links to global expansion of harmful cyanobacteriaWater Research, 2012
- CHANGES IN TURBULENT MIXING SHIFT COMPETITION FOR LIGHT BETWEEN PHYTOPLANKTON SPECIESEcology, 2004
- Effects of experimentally induced cyanobacterial blooms on crustacean zooplankton communitiesFreshwater Biology, 2003