Assessment of hydrogeochemical characteristics of groundwater in parts of Hindon-Yamuna interfluve region, Baghpat District, western Uttar Pradesh

Distribution, health risk assessment, and anthropogenic sources of fluoride in farmland soils in phosphate industrial area, southwest China

The high concentration of fluoride (F) in soils has become a rising concern for its toxicity to microbes, plants, animals and human health. In the present study, the spatial and vertical distribution, health risk assessment and anthropogenic sources of F in farmland soils in an industrial area dominated by phosphate chemical plants were studied. Concentrations of total fluoride (TF) and water soluble fluoride (WSF) in the surface soils decreased with distance within the range of 2500 m at the prevailing downwind of the industrial area. The soil TF and WSF concentrations in 0-40 cm profiles were higher than those in 40-100 cm layers in the industrial area. At the prevailing downwind of the industrial area within 700 m, the hazard quotient values of human exposure to surface soils were higher than 1, indicating that a potential risk may exist for human health in this area. The main exposure pathway for children and adults was oral ingestion and particulate inhalation, respectively. The source apportionment model of soil F was modified based on years' historical data and experimental data. The results showed that the proportion of anthropogenic sources of soil F was dustfalls (69%) > irrigation water (23%) > air (5%) > chemical fertilizers (3%) in the industrial area. The high F concentration of dustfalls was mainly due to the phosphate rock, phosphogypsum, and surface soils with high F contents from the factories. In order to safeguard human health and alleviate hazards of F to surroundings, the control of pollutants emission from factories was a basic and vital step to reduce F in the soils in industrial areas.

Fluoride distribution and contamination in the water, soil and plants continuum and its remedial technologies, an Indian perspective- a review

Fluorine is an essential element required in trace amounts but gets toxic for human beings at levels more than 1.5 mg F^- L^-1 primarily through drinking contaminated water. It is the 13th most abundant element and constitutes about 0.06-0.09% in the earth crust. It is electronegative in aqueous medium forming fluoride ion (F^-). Fluoride contamination in the environment occurs mostly due to anthropogenic and geogenic sources. Fluoride is widely distributed in all components of environment, air (0.1-0.6 μg L^-1) soils (150-400 mg Kg^-1) rocks (100-2000 mg Kg^-1), plant (0.01-42 mg Kg^-1) and water (1.0-38.5 mg L^-1). Human beings and animals are being exposed to F^- primarily from water (0.2-42.0 mg L^-1) and plants (0.77-29.5 μg g^-1). Fluorosis, a health hazard due to F^- is a major problem in many countries across the world affecting about 200 million people globally. In India, > 62 million people in twenty states are facing problem due to F^-. The most affected states are Rajasthan (7670 habitations), Telangana (1,174 habitations) and Karnataka (1122 habitations). To mitigate this problem, there is an urgent need to understand the current status and brief knowledge of F^- geochemistry. The objective of this review is to highlight different sources of F^- that contaminate different environmental matrices including plants, the extent of contamination level in India, uptake, translocation and toxicity mechanism in plants. The review also highlights currently available mitigation methods or technologies through physio-chemical and biological means.