Organic coagulants as turbidity removal in water treatment and their toxicity to freshwater fauna:Areview

Abstract

Water that is free from toxicants ('safe water') is essential to farmers and aquatic life. Globally, synthetic coagulants are issue of public health concern due to their longterm and non-biodegradable effects on human and aquatic life. The synthetic coagulants have been implicated in the causes of Alzheimer, cancer and bioaccumulation along food chain in aquatic environment. However, the world is tending towards organic products to promote her health safety due to environmental friendliness of organic based products to human and aquatic health. There has been considerable interest in the use of natural coagulants in water treatment prior to supply of water to the community. Organic coagulants are biodegradable, cost-effective and environmental friendly compare to the synthetic coagulants used in water treatment as turbidity removal. The preparation of water supply to public as potable water requires a lot of treatments which include coagulation and clarification of suspended particles. However, aquatic ecosystem is the final receiving body at risk of toxicants exposure due to their toxicity effects on fish and non-target species organs and tissues. Their toxicity level to aquatic and non-target organisms is essential for baseline information on the dosages that will not be harmful to aquatic life. This paper therefore reviewed some available organic coagulants in public water treatment, their level of toxicity to different freshwater fish species and non- target aquatic fauna, health implication on consumers of fish exposed to these coagulants. Public recommendations on their uses and health implications were addressed.