Risk assessment of fluoride in dirinking water and food chain and performance study of defluoridation unit

Abstract

Ground water is the major source for various purpose in the world. Presence of low or high concentration of certain ions is a major issue as they make the ground water unsuitable for various purposes. Fluoride is one such ion that causes health problems in people living in more than 25 nations in the world. Fluoride concentration of at least 0.6 mg/l is required for human consumption as it helps to develop stronger teeth and bones. Consumption of water with fluoride concentration above 1.5 mg/l results in acute to chronic dental fluorosis where the tooth becomes colored from yellow to brown. Skeletal fluorosis which causes weakness and bending of the bones also results due to long term consumption of water containing high fluoride. Presence of low or high concentration of fluoride in groundwater is because of natural or anthropogenic causes or a combination of both. Natural sources are associated to the geological conditions of an area. Several rocks have fluoride bearing minerals like apatite, fluorite, biotite and hornblende. But not only in tea there are so many food items that consume fluoride. Tea when mixed with water it has a high concentration of fluoride. Apart from tea in Hazmola, Hazmi Guli, Black Salt it also consume fluoride. Shrimp, blue crabs, soda, raisins also have a certain amount of water. Fluoride in limited amount is considered to be useful, but presence of high concentration of fluoride leads to a severe damage to human body. In this paper we have discussed about lots of defluoridation method. Nalgonda, Revese osmosis, Nano Technology, Electrocoagulation, adsorption. Among them here we choose a method named as adsorption method. Fluoride contamination in drinking water due to natural and anthropogenic activities has been recognized as one of the major problems worldwide imposing a serious threat to human health. Among several treatment technologies applied for fluoride removal, adsorption process has been explored widely and offers satisfactory results especially with mineral-based and/or surface modified adsorbents. In this review, an extensive list of various adsorbents from literature has been compiled and their adsorption capacities under various conditions (pH, initial fluoride concentration, temperature, contact time, adsorbent surface charge, etc.) for fluoride removal as available in the literature are presented along with highlighting and discussing the key advancement on the preparation of novel adsorbents tested so far for fluoride removal. It is evident from the literature survey that various adsorbents have shown good potential for the removal of fluoride. However, still there is a need to find out the practical utility of such developed adsorbents on a commercial scale, leading to the improvement of pollution control. This study showed that Fluoride is not only available in tea. It is also available in different types of food samples. The aim of this research work is to assess the concentration of fluoride in water & food product sample and develop a sustainable treatment methodology and evaluate its efficacy. The study results shows that the percentage of fluoride removal by adsorption process using activated alumina is 76.13 % which can used as sustainable fluoride removal methodology. Key Words: Fluoride, Fluorosis, Food, Adsorption, Fluoride removal technology, Health impact, Water quality.