Laboratory of Ecology and Physiology of Phytoplankton, Department of Plant Biology, University of Rio de Janeiro State, Rua São Francisco Xavier 524-PHLC Sala 511a, Rio de Janeiro 20550-900, Brazil.
Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo 05508-900, Brazil.
Toxins (Basel). 2021 Jun 8;13(6):405. doi: 10.3390/toxins13060405.
Combining coagulants with ballast (natural soil or modified clay) to remove cyanobacteria from the water column is a promising tool to mitigate nuisance blooms. Nevertheless, the possible effects of this technique on different toxin-producing cyanobacteria species have not been thoroughly investigated. This laboratory study evaluated the potential effects of the "Floc and Sink" technique on releasing microcystins (MC) from the precipitated biomass. A combined treatment of polyaluminium chloride (PAC) with lanthanum modified bentonite (LMB) and/or local red soil (LRS) was applied to the bloom material (mainly and ) of a tropical reservoir. Intra and extracellular MC and biomass removal were evaluated. PAC alone was not efficient to remove the biomass, while PAC + LMB + LRS was the most efficient and removed 4.3-7.5 times more biomass than other treatments. Intracellular MC concentrations ranged between 12 and 2.180 µg L independent from the biomass. PAC treatment increased extracellular MC concentrations from 3.5 to 6 times. However, when combined with ballast, extracellular MC was up to 4.2 times lower in the top of the test tubes. Nevertheless, PAC + LRS and PAC + LMB + LRS treatments showed extracellular MC concentration eight times higher than controls in the bottom. Our results showed that Floc and Sink appears to be more promising in removing cyanobacteria and extracellular MC from the water column than a sole coagulant (PAC).
将混凝剂与压载物（天然土壤或改性粘土）结合起来，从水柱中去除蓝藻是一种很有前途的方法，可以减轻有害藻类的爆发。然而，这种技术对不同产毒蓝藻物种的可能影响尚未得到彻底研究。本实验室研究评估了“絮凝和沉降”技术从沉淀生物量中释放微囊藻毒素（MC）的潜在影响。采用聚合氯化铝（PAC）与镧改性膨润土（LMB）和/或当地红土（LRS）联合处理热带水库的水华材料（主要是 和 ）。评估了细胞内和细胞外 MC 和生物量的去除情况。单独使用 PAC 不能有效地去除生物量，而 PAC + LMB + LRS 是最有效的，比其他处理方法去除的生物量多 4.3-7.5 倍。细胞内 MC 浓度在 12 到 2.180 µg L 之间，与生物量无关。PAC 处理使细胞外 MC 浓度增加了 3.5 到 6 倍。然而，当与压载物结合时，在试管顶部的细胞外 MC 浓度降低了 4.2 倍。然而，PAC + LRS 和 PAC + LMB + LRS 处理在底部的细胞外 MC 浓度比对照组高 8 倍。我们的结果表明，与单独使用混凝剂（PAC）相比，絮凝沉降法更有希望从水柱中去除蓝藻和细胞外 MC。
