Presented at the “Geological Society of America (GSA ...



Presented at the “Geological Society of America (GSA) Annual Meeting and Exposition”, Portland, Oregon, USA (October 20, 2009)

Session number 174: Geochemistry of Arsenic and Other Toxic Elements and Assessment of Environmental Risks in Global Groundwater Systems

Title: FLUOROSIS AND ARSENICOSIS – A Review

KODALI, Lakshmi Narasimha Rao

Professor & Chair (Retired), Dept. of Geology

S. V. University, Tirupati-517502, India

Email: kodalinarasimha@

PREAMBLE: Water is vital for survival and sustainable development of any civil society. People's lives and livelihoods depend on water. People in many areas of the world lack the fresh, drinkable water for their survival. Over 1 billion people around the world still use unsafe drinking water sources, leading to health disorders. Globally between 1,085.000 and 2,187,000 deaths due to diarrhoeal diseases can be attributed to the 'water, sanitation and hygiene' risk factor,90% of them among children under five(6,000 children die each day from preventable water-related diseases).Improvements in safe water supply, and in particular in hygiene and sanitation could reduce the number of deaths due to diarrhoea by more than 50%.Polluted water can transmit diseases and carry poisonous chemicals, which can make people sick and even kill. In some areas, groundwater may contain enhanced levels of natural substances that can restrict its use. Groundwater may also contain soluble natural substances like arsenic, fluorine, nitrate or sulphate, which restrict or even prevent its direct use because of health concerns. Although several sources of fluorine have been mentioned, only fluoride content in ground waters, beyond toxic limits, known as fluorosis, have been studied, taking a case study from Anantapur District, South India; and arsenicosis -- the two endemic disorders crippling millions of people in India and Bangladesh. In the present report, an attempt has been made to review the status of fluorosis (dental and skeletal) and arsenicosis.

FLUOROSIS:

Fluoride is a component of human and animal tissue developed mostly on bones and teeth. While fluoride in very limited quantities is desirable for the healthy growth of bones and teeth in human beings, it would have toxic effects, if present in excess quantities in water and foods taken by them. This toxicity would be reflected as a disease called fluorosis. Ever since Eager, in 1901, reported mottled enamel of teeth among the emigrants from Pozzuli, Italy, such reports came from many other parts in the world, viz., Pennsylvania and Arizona(in USA),China, India, West Indies, Spain, Holland, Mexico, and several other North African and South American countries. This disorder was observed in children drinking high fluoride water. If fluoride content is around 1.5 mg/l and 2.5 mg/l, mild dental fluorosis/mottling (later renamed as dental fluorosis) may develop. A more severe type of fluorosis called “Skeletal Fluorosis or Osteofluorosis”, (if the fluoride content of drinking water is more than 2.5 mg/l ) may develop , among adults under Indian conditions, affecting bones and joints, was first discovered by Moeller and Gudjonsson in 1932,as to ingestion of water of still higher concentration of fluoride for several years . The work of the King's Institute of Preventive Medicine from Chennai (Madras) revealed for the first time in1937, the occurrence of both dental and skeletal fluorosis on an endemic scale from a cluster of villages around Podili and Darsi of Prakasam District in Andhra Pradesh, India. The work of the National Institute of Nutrition at Hyderabad in 1977 revealed the spread of endemic 'Genu Valgum (knock-knee)’ crippling lower limbs right from childhood in association with fluorosis in most parts in India. This is just the opposite of rickets (bow legs), caused by deficiency of D-vitamin and calcium (feet are apart when knees are together). Genu valgum was not found even in the fluorosis areas of India till around 1977. It is not reported to have been associated with the fluorosis-endemic areas in other parts of the world. Although preliminary work revealed that genu valgum is caused by drinking waters poor in calcium and rich in molybdenum, efforts should be taken up to know its exact cause and prevent its widespread occurrence in the fluorosis areas in India. The work of several investigators has revealed that fluorosis spreads now among 67 million people in the entire arid and semi-arid tracts of India.

The authors work revealed that the fluorine content of rocks in India at most places are much less than that in most developed countries. Despite that the fluoride content of ground water in India is much higher than in most developed countries. As a result, fluorosis caused by excess fluoride in water is widespread in India. The authors' study revealed, based on the distribution pattern of fluoride toxicity in waters of Anantapur District , South India, that the severity of the problem is more acute, as only 30% of the villages have the fluoride content in drinking waters within the permissible limit (1.5 mg/l),and 70% of the villages above the permissible limit (> 1.5 mg/l). The governmental efforts to eradicate these disorders by supplying low-fluoride water to the communities could not so eradicate the problem. In the present report, an attempt has been made to review the status of fluorosis (dental & skeletal) and genu valgum, and solving the problem in a cost-effective way, through an interdisciplinary approach, which includes identification of local low-fluoride sources of ground water, creation of individual sources of drinking water through rainwater harvesting and selection of locally available foods of high nutritive value. Geochemists have established that the fluorine content of the Earth's crust is 950 mg/ton, while chlorine content is over 7 times less than that. Despite that, seawater contains 1.3 mg/l fluoride as against 19,500 mg/l chloride. This indicates that the natural environment of the Earth is highly unfavorable for the mobility of fluoride. Fluoride however becomes mobile in shallow ground water through alkalization. This happens in the vicinity of minor surface water bodies such as tanks in regions having hot arid/ semiarid climate and poor drainage. Under such conditions groundwater gets enriched in Na HCO3 CO3 and F and impoverished in Ca. There is a need for hydro geologists to take up reclamation of alkaline groundwater through gypsum treatment and thereby immobilize HCO3 CO3 and F as calcite and fluorite.

ARSENICOSIS

Arsenicosis is caused as a result of drinking of high-arsenic contaminated ground water, and is a major health hazard throughout the world, including India. Arsenic contamination in water has been reported from more than 30 countries in the world. It is estimated that arsenicosis spreads over 25 million people in Bangladesh, and 6 million in West Bengal of India. In addition, arsenic contamination has been found in the States of Bihar, Uttar Pradesh, Jharkhand, Assam, Chattisgarh and Andhra Pradesh. Geochemical research has shown that arsenic may be released from both reductive dissolution of Fe and Mn hydroxide, and microbial oxidation of organic matter. The effects of arsenic toxicity can be categorized into non-carcinogenic and carcinogenic effects:

NON-CARCINOGENIC EFFECTS

The minimum arsenic concentration in drinking water producing dermatologic lesions is found to be 0.00103 mg/l. Dermal lesions such as hyperkeratosis and diffuse or spotted hyperpigmentation over palms and soles are the diagnostic features of chronic arsenicosis. Non-cancerous effects may be multisystemic involving peripheral vascular, respiratory, cardiovascular, cerebrovascular diseases, diabetes, and adverse reproductive outcomes.

CARCINOGENIC EFFECTS

Epidemiologic data from regions of the world with very high levels of arsenic in drinking water (>150 ug/l) show a strong association between arsenic exposure and risk of several internal cancers. Chronic arsenic toxicity (CAT) leads to cancers of skin, liver, lungs, kidney and bladder. Malnutrition may increase risks from synergistically in causing lung cancer.

ARSENIC REMOVAL TECHNIQUES

Several low cost chemical treatments like ion exchange, filtration and adsorption along with bioremediation may be useful for arsenic removal from drinking water. In India well-head arsenic removal units are used in remote villages of West Bengal. Every component of the arsenic removal treatment system including activated alumina sorbent is procured indigenously. Each unit serves approximately 200-300 households and contains about 100 l of activated alumina. No chemical addition, pH adjustment or electricity is required for operating these units. The arsenic concentration in the influent varies from around 100 ug/l to greater than 500 ug/l. In the treated water, arsenic concentration is consistently below 50 ug/l.

Adsorptive filtration - Polystyrene and PolyHIPE coated with adsorbing agents like iron hydroxides are capable of arsenic removal.

Hydrotalcite can be used for the removal of arsenite (As (III)) and arsenate (As (V)) from the drinking water.

Cases of arsenicosis have been reported from Anantapur district, A.P., India, and further investigation is under progress. However, it has been suggested that stoppage of drinking high arsenic contaminated groundwater would be the best remedial solution. Various treatment modalities for arsenicosis are symptomatic and are not yielding the desired results.

SELECTED BIBLIOGRAPHY

Krishna Reddy, T.V. and Jagadiswara Rao, R., 2001.Fluorosis and genu valgum in India - a result of man-induced alkalization of groundwater. At IAH/ATH Conference, Munich, Germany, Aug. 2001.

Narasimha Rao, K.L. and Jagadiswara Rao, R., 2001. Role of social workers in the eradication of fluorosis and genu valgum in India. At the 3rd International Conference on Social Work in Health and Mental Health, July 1-5, 2001 Tampere, Finland.

Narasimha Rao, K.L. and Jagadiswara Rao, R., 2003. Biological and Chemical pollution: Lessons learnt from Hydrocide development in India. In SIWI Proceedings, SIWI Seminar-Towards catchment Hydrosolidarity in a World of Uncertainties, Stockholm, Sweden, 16 Aug.2003.

Narasimha Rao, K.L. and Jagadiswara Rao, R., and Padma Bharathi Devi, M., 2006. Toxins in the Water: Fluorosis and Arsenicosis in India and Bangladesh - Retrospect and Prospect. Presented at the 4th Annual Western Regional Health Conference - “Health, Human Rights and Economics: The Value of Human Life”, Feb.18, 2006, Portland, OR, USA.

Guha Mazumder, D.N., 2008.Chronic arsenic toxicity and human health, Indian J. Med. Res. 128,

pp. 436-447.

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