Evaluation of using aluminum sulfate and water-soluble Moringa oleifera seed lectin to reduce turbidity and toxicity of polluted stream water

• Published in: Chemosphere (Oxford) 2016-11, Vol.163, p.133-141
• Main Authors: Freitas, José Henrique Edmilson Souza, de Santana, Keissy Vanderley, do Nascimento, Ana Cláudia Claudina, de Paiva, Sérgio Carvalho, de Moura, Maiara Celine, Coelho, Luana Cassandra Breitenbach Barroso, de Oliveira, Maria Betânia Melo, Paiva, Patrícia Maria Guedes, do Nascimento, Aline Elesbão, Napoleão, Thiago Henrique
• Format: Article
• Language: English
• Subjects: Alum Compounds - chemistry; Animals; Aquatic ecosystems; Artemia - drug effects; Artemia salina; Brassicaceae - drug effects; Brazil; Ecotoxicology; Environmental Restoration and Remediation - methods; Eruca sativa; Lactuca - drug effects; Lactuca sativa; Lectin; Moringa oleifera; Moringa oleifera - metabolism; Physicochemical analysis; Plant Extracts - chemistry; Plant Lectins - chemistry; Rivers - chemistry; Seeds - chemistry; Water - analysis; Water Pollution - analysis; Water Purification - methods; Water quality
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2016.08.019

Aluminum salts are used as coagulants in water treatment; however, the exposure to residual aluminum has been associated with human brain lesions. The water-soluble Moringa oleifera lectin (WSMoL), which is extracted with distilled water and isolated by chitin chromatography, has coagulant activity and is able to reduce the concentration of metal ions in aqueous solutions. This study evaluated the potential of using aluminum sulfate and WSMoL to reduce the turbidity and toxicity of water from the Cavouco stream located in Recife, Pernambuco, Brazil. The water sample used (called P1) was collected from the stream source, which was found to be strongly polluted based on physicochemical and water quality analyses, as well as ecotoxicity assays with Artemia salina and seeds of Eruca sativa and Lactuca sativa. The assays combining WSMoL and aluminum sulfate were more efficient than those that used these agents separately. Furthermore, the greatest reduction in turbidity (96.8%) was obtained with the treatment using aluminum sulfate followed by WSMoL, compared to when they were applied simultaneously (91.3%). In addition, aluminum sulfate followed by WSMoL treatment resulted in residual aluminum concentration (0.3 mg/L) that was much lower than that recorded after the treatment using only the salt (35.5 mg/L). The ecotoxicity of P1 was also strongly reduced after the treatments. In summary, the combined use of aluminum sulfate and WSMoL was efficient in promoting a strong reduction of turbidity and ecotoxicity of a polluted water sample, without resulting in a high residual aluminum concentration at the conclusion of the treatment. •Coagulants were evaluated for reduction of turbidity and toxicity of Cavouco stream water.•The treatments used aluminum sulfate (AS) and water-soluble Moringa oleifera seed lectin (WSMoL) both separated and together.•Treatment using AS followed by WSMoL was the most effective in reducing turbidity.•The use of WSMoL after AS treatment decreased the residual aluminum concentration.•Reduction of ecotoxicity was also detected in water treated with AS and WSMoL.