Fluoride occurrence in the groundwater in a coastal region of Andhra Pradesh, India

Abstract

Fluoride (F -) content varies from 0.60 to 1.80 mg/L in the coastal region between Chirala and Ongole of Andhra Pradesh, India. It exceeds the threshold limit of 1.20 mg/L in 20 % of the total groundwater samples. The aim of the present study is to assess the controlling factors of F -content. The study area experiences a dry climate and is underlain by Charnockite Group of rocks over which the river and coastal alluvium occur. The

Worldwide contamination of water by fluoride

“…The first case of fluorosis was reported in Prakasam district of Andhra Pradesh (Fig. 2) by Shortt et al (1937). However, the effect of fluoride contamination in India is most profound in the state of Rajasthan (Fig.…”

Assessment of fluoride contamination and distribution: a case study from a rural part of Andhra Pradesh, India

“…Similar investigations using the Gibbs diagram such as Adimalla et al (2018a) have found that elevated concentrations of fluoride are associated with groundwater that plots in the "rock dominance" field in a Gibbs diagram. Similarly, observations were noticed in Kolar and Tumkur Districts of Karnataka (Mamatha and Rao 2010), Chirala and Ongole of Andhra Pradesh (Subba Rao et al 2015;Rao et al 2017), and Chimakurthy pluton, Prakasam District, Andhra Pradesh (Reddy et al 2016). However, it is also supported by the existing negative correlation between fluoride and nitrate (Fig.…”

“…Moreover, 34% of groundwater samples are found under Na + -HCO 3 − or mixed type (Na + -K + -HCO 3 − ) and cause favor to fluoride dissolution in the study region. A number of previous studies suggested that the Na + -HCO 3 − water type, decreasing calcium concentration, increasing sodium concentration, and neutral-to-alkaline pH nature of water are more favorable for fluoride dissolution process, thereby accelerating the fluoride concentration in groundwater (Rao et al 2017;Ali et al 2016;Adimalla et al 2018a, b;Narsimha and Sudarshan 2017b). Moreover, Na + -HCO 3 − water type, mainly deeper groundwater, is influenced by the ion exchange process (Saxena and Ahmed 2003).…”

“…lepidolite, montmorillonite, kaolinite, pegmatite, mica, clays, villuanite, phosphorite, and some micas weathered from silicates, igneous, and sedimentary rocks, especially shale (Adimalla et al 2018a;Ayoob and Gupta 2006;Sudarshan 2017a, 2018a, b), and high rates of evaporation and low precipitation in arid and semiarid areas can also contribute to the fluoride enrichment Venkatayogi 2017, 2018;Subba Rao et al 2015). However, fluoride is an important element for human health which has certain limits for intake (Rao et al 2017;Ali et al 2016;Narsimha and Sudarshan 2017a, b). World Health Organization (WHO 1984) has fixed a safe limit for fluoride from 0.5 to 1.5 mg/L in drinking water.…”

“…Moreover, the intake of drinking water with fluoride content less than 0.5 mg/L can cause tooth decay. Larger than 1.5 mg/L fluoride content in drinking water is risky for human consumption which leads to dental fluorosis and skeletal fluorosis when exceeds 3 mg/L (Ayoob and Gupta 2006;Rao et al 2017;Wu and Sun 2016).…”