Complex effects of dissolved organic matter, temperature, and initial bloom density on the efficacy of hydrogen peroxide to control cyanobacteria

Abstract

Harmful cyanobacterial blooms plague reservoirs and lakes used for a variety of purposes. Chemical controls are frequently used to mitigate the occurrence of cyanobacterial blooms given that many are fast-acting and effective at reducing cyanobacterial abundance. Recent research has identi ed hydrogen peroxide (H 2 O 2 ) as an environmentally-friendly alternative to algaecides that have typically been used, such as copper sulfate. To build on past studies, these experiments sought to further understand how well H 2 O 2 treatments reduce cyanobacteria in complex eutrophic conditions. We assessed the effectiveness of H 2 O 2 (at treatments of 2-16 mg L -1 ) under varying environmental conditions in a controlled laboratory setting, including (1) dissolved organic matter (DOM) concentrations (humic acid; 0 -60 mg L -1 ), ( 2) temperatures (20, 25, and 32 °C), and (3) initial algal biomass (82 -371 µg L -1 as chlorophyll). In contrast to our expectations, neither DOM concentration nor temperature meaningfully impacted the effectiveness of H 2 O 2 at reducing cyanobacteria. However, initial algal biomass as well as H 2 O 2 treatment greatly in uenced the effectiveness of the algaecide. Across all experiments, H 2 O 2 concentrations of 0.03 -0.12 mg H 2 O 2 L -1 /µg chlorophyll L -1 were effective at signi cantly reducing cyanobacteria. Thus, water resource managers are encouraged to consider how ambient levels of algal biomass may affect the ability of H 2 O 2 to control algal blooms prior to treatment. Highlights 1. The effect of hydrogen peroxide on cyanobacteria was assessed under varying conditions.2. Neither dissolved organic matter concentration nor temperature meaningfully reduced the e cacy of hydrogen peroxide.3. Initial algal biomass negatively in uenced the e cacy of hydrogen peroxide.

Hydrogen peroxide as a mitigation against Microcystis sp. bloom

“…In addition further studies regarding the effectiveness of H 2 O 2 when varying levels of chlorophyll, total suspended solids, and volatile suspended solids are in the water would be helpful for adjusting concentrations of H 2 O 2 for treatment purposes. Buley et al (2023) suggested that the initial algal biomass could impact the effectiveness of H 2 O 2.…”

“…Further it may be selective for killing Microcystis sp.. Many of the studies published on the efficacy of H 2 O 2 were conducted in a laboratory ( Buley et al, 2023 ; Chen et al, 2021 ; Guo et al, 2021 ; Mukai et al, 2019 ), so the effect might differ in field applications.…”

Treatment Effect of Long-Term Subsurface-Flow Constructed Wetland on Mariculture Water and Analysis of Wetland Bacterial Community

“…The results showed that the microbial diversity and richness of the substrate were significantly greater than those measured for the water sample. Under anaerobic condi- Currently, chemical measures are usually used to regulate the planktonic state of the water, such as the addition of copper sulfate [26,27]. Although the treatment effect is good, there are chemical residues and cost problems.…”