Fluoride is known to occur at elevated concentrations in a number of parts of the world where it can be a significant cause of disease. The primary focus of Fluoride in Drinking Water is the prevention of adverse health effects from excessive levels of fluoride in drinking water. The book fills the urgent need, identified for updating the WHO Guidelines for Drinking-water Quality, for information on the occurrence of fluoride, its health effects, ways of reducing excess levels and methods for analysis of fluoride in water. The draft document, produced by a working group of experts convened to consider protection from fluoride and its control, was issued for extensive review and consultation. The resultant book, which incorporates the comments received, was further peer review by experts in developed and developing countries. It is aimed at a wide range of individuals, including health workers and sanitary engineers who may require a broad introduction to the subject with more detailed guidance in some specific areas. Fluoride in Drinking-water will be an invaluable reference source for all those concerned with the management of drinking-water containing fluoride and the health effects arising from its consumption, including water sector managers and practitioners as well as health sector staff at policy and implementation levels. It will also be of interest to researchers, students, and development workers and consultants. Contents Introduction Environmental occurrence, geochemistry and exposure Human health effects Guidelines and standards Removal of excessive fluoride Analytical methods Country data on dental and skeletal fluorosis associated with exposure to fluoride through drinking water Appendix: Indices of severity of dental fluorosis

Fluoride in Drinking-Water

The element fluorine has long been recognised to have benefits for dental health: low-fluoride intake has been linked to development of dental caries and the use of fluoride toothpastes and mouthwashes is widely advocated in mitigating dental health problems. Fluoridation of water supplies to augment naturally low fluoride concentrations is also undertaken in some countries. However, despite the benefits , optimal doses of fluoride appear to fall within a narrow range. The detrimental effects of ingestion of excessive doses of fluoride are also well documented. Chronic ingestion of high doses has been linked to the development of dental fluorosis, and in extreme cases, skeletal fluorosis. High doses have also been linked to cancer (Marshall 1990), although the association is not well-established (Hamilton 1992).

Fluoride in Natural Waters

Sources, behaviour, and environmental and human health risks of high-technology rare earth elements as emerging contaminants.

Fluoride contamination in water is a major problem across the globe, with health hazards such as dental and skeletal fluorosis. Most earlier studies are confined to local or regional scales. As the problem has serious socioeconomic implications, there is a need for a global perspective. Thus, here we review worldwide research for nearly a century on fluoride contamination in water. We investigated the distribution of fluoride contamination in water, its sources, mobilization and association. The major findings are: (1) Anomalous fluoride concentration in groundwater is mainly confined to arid and semiarid regions of Asia and North Africa. (2) The geogenic sources of fluoride in water are mainly fluorine-bearing minerals in rocks and sediments, whereas anthropogenic sources of fluoride in water are mainly pesticides and industrial waste. (3) Fluoride mobilization from geogenic sources is mainly controlled by alkalinity and temperature. (4) Fluoride occurrence in water is associated with ions such as sodium, arsenic chloride and bicarbonate. There are few associations of fluoride in water with calcium and magnesium.

Worldwide contamination of water by fluoride

Controls on elevated fluoride and arsenic concentrations in groundwater from the Yuncheng Basin, China

The geographic distribution of fluoride in surface and groundwater in Ethiopia with an emphasis on the Rift Valley.

Back ground: The practice of traditional medicine for the control of fertility in rural Ethiopia is based on folk use of numerous antifertility herbs and Achyranthes aspera is one of these used for this purpose. Many plants are known to possess anti-fertility effect through their action on hypothlamo-pituitary-gonadal axis or direct hormonal effects on reproductive organs resulting in inhibition of ovarian steroidogenesis. Objectives: The present study focused to investigate the effect of methanolic leaves extract of Achyranthes aspera L. on some indicators for anti-fertility activities such as abortifacient, estrogenesity, pituitary weight, and ovarian hormone level and lipids profile in female rats, in attempt to validate the traditional claim. Methods: The abortifacient effect of the methanolic extract of the leaves of Achyranthes aspera was determined by counting the dead fetuses in vivo. Effect on estrogenesity was assessed by taking the ratio of the uterine weight to body weight. The ratio of the pituitary weight to body weight was also calculated. The effect of the extract on the level of ovarian hormones and lipid profile was evaluated using electrochemiluminescence immunoassay. Results: The extract showed significant (p<0.05) abortifacient activity and increased pituitary and uterine wet weights in ovarectimized rats. The extract, however, did not significantly influence serum concentration of the ovarian hormones and various lipids except lowering HDL at doses tested. Conclusion: The methanolic leaves extract of Achyranthes aspera possesses anti-fertility activity, which might be exploited to prevent

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Effect of achyranthes aspera L. on fetal abortion, uterine and pituitary weights, serum lipids and hormones

Antipyretic properties of the aqueous and ethanol extracts of the leaves of Ocimum suave and Ocimum lamiifolium in mice

Phytochemical screening and pharmacological evaluations for the antifertility effect of the methanolic root extract of Rumex steudelii.

Objective: To investigate the anti-fertility effect of Ricinus communis seed extract. Design: Laboratory-based experiment. Setting: Laboratory of the Department of Pharmacology, Faculty of Medicine, Addis Ababa University, Addis Ababa, Ethiopia in 1996. Results: The seed extract was found to possess anti-implantation and abortifacient effects. It was also observed that the seed extract prolonged the oestrus cycle of guinea pigs. The dioestrus phase was significantly prolonged as well. After stopping administering the extract, however, the normal dioestrus phase and oestrus cycle started to resume. The seed extract also reduced the weight of the uterus without affecting that of the ovaries significantly. Conclusion: Ricinus communis possesses an anti-fertility effect in female guinea pigs, which might be extrapolated in human beings. These findings might support the accredited claim of its traditional use to avoid unwanted pregnancies. Further studies, however, should be pursued.

Legesse Zerihun

Papers

The geographic distribution of fluoride in surface and groundwater in Ethiopia with an emphasis on the Rift Valley.

Effect of achyranthes aspera L. on fetal abortion, uterine and pituitary weights, serum lipids and hormones

Antipyretic properties of the aqueous and ethanol extracts of the leaves of Ocimum suave and Ocimum lamiifolium in mice

Phytochemical screening and pharmacological evaluations for the antifertility effect of the methanolic root extract of Rumex steudelii.

Antifertility activity of Ricinus communis seed in female guinea pigs.