Citation:

Struewing, I., N. Sienkiewicz, C. Zhang, N. Dugan, AND J. Lu. Effective Early Treatment of Microcystis Exponential Growth and Microcystin Production with Hydrogen Peroxide and Hydroxyapatite. Toxins. MDPI, Basel, Switzerland, 15(1):3, (2023). https://doi.org/10.3390/toxins15010003

Impact/Purpose:

1) Public concern over cyanobacterial blooms has increased due to their higher frequency of occurrences and their potential ecological and health impacts. 2) Microcystis is the major cyanotoxin producer in surface freshwater ecosystems. Preventing cyanotoxin production is essential to protect aquatic ecosystems and public health. However, current harmful cyanobacterial bloom (HCB) control strategies have significant shortcomings. 3) This study that is to develop an effective HCB control approach that takes action before exponential cyanobacterial growth and massive cyanotoxin production can provide a strategy to mitigate cyanotoxin production. 4) OW, regional offices, scientists and water quality managers could be interested in the results.

Description:

Mitigating cyanotoxin production is essential to protecting aquatic ecosystems and public health. However, current harmful cyanobacterial bloom (HCB) control strategies have significant shortcomings. Because predicting HCBs is difficult, current HCB control strategies are employed when heavy HCBs have already occurred. Our pilot study developed an effective HCB prediction approach that is employed before exponential cyanobacterial growth and massive cyanotoxin production can occur. We used a quantitative polymerase chain reaction (qPCR) assay targeting the toxin-encoding gene mcyA to signal the timing of treatment. When control measures were applied at an early growth stage or one week before the exponential growth of Microcystis aeruginosa (predicted by qPCR signals), both hydrogen peroxide (H2O2) and the adsorbent hydroxyapatite (HAP) effectively stopped M. aeruginosa growth and microcystin (MC) production. Treatment with either H2O2 (10 mg·L−1) or HAP (40 µm particles at 2.5 g·L−1) significantly reduced both mcyA gene copies and MC levels compared with the control in a dose-dependent manner. While both treatments reduced MC levels similarly, HAP showed a greater ability to reduce mcyA gene abundance. Under laboratory culture conditions, H2O2 and HAP also prevented MC production when applied at the early stages of the bloom when mcyA gene abundance was below 105 copies·mL−1.

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