Evaluation and Treatment

*Resources of Water*

2014. 103 p

2014. 11 p

Horizon 2035; Rapport Final: Volume I;

[36] AFD. Programme d'urgence pour la sécurisation de l'alimentation en eau potable de Dakar. Note de communication publique d'opération république du Sénégal: CSN1446;

[37] Ndour N. Etat d'avancement du processus de suivi de l'ODD6 de l'initiative GEMI au Sénégal. Conférence internationale sur les Objectifs de Développement Durable (0DD): Quel agenda pour le Sénégal ?12-13 octobre 2016, Dakar, Sénégal; 2016. 14 p

**120**

**Chapter 9**

Yemen

**Abstract**

*and Driss Belghyti*

GIS and Statistical Evaluation of

of Upper Rasyan Aquifer, Taiz,

*Ramzy Saeed Mahbob Naser, Mohammed El Bakkali*

water, the arid climatic and the activities agriculture.

upper Wadi Rasyan, Taiz and Yemen

**1. Introduction**

**123**

Fluoride Content in Southern Part

Fluorosis continues to be an endemic problem in Yemen. More areas are being affected by fluorosis in different parts of this country. The present study aims to identify the intensity and the spatial extent of fluoride concentration in groundwater of the southern part of the upper Wadi Rasyan, Taiz, Yemen. 93 sampling points were selected; the sampling included all types of sources of groundwater and all types of aquifers. The results show that 71% of samples exceed the WHO drinking water guidelines value of 1.5 mg/l, and there are wide variation for groundwater's content of fluoride in the same aquifer (whether, volcanic and alluvial) and in the same of groundwater type, and these variations between the different water types or between the different depths of water (alluvial and volcanic aquifers) are not significantly different. The high concentration of fluoride in groundwater of the volcanic aquifer is likely because of the nature of geology formations by the waterrock interaction result of long-time residence of water in contact with the geology formation. The high concentration of fluoride in the alluvial aquifer likely resulting the waste of urban and industrial activates sources, the over exploration of ground-

**Keywords:** fluoride, spatial distribution, GIS, Al-Burayhi and Hedran, Al-Hawban,

Fluorine has the highest chemical reactivity among all known elements and occurs mainly as free fluoride ions in natural waters, although some fluoride complexes also exist under specific conditions [1]. In groundwater, the natural concentration of fluoride depends on the geological, chemical and physical characteristics of the aquifer, the porosity and acidity of the soil and rocks, the temperature and the action of other chemical elements [2]. Fluoride ion in drinking water is known for both beneficial and detrimental effects on health. Fluoride in small amounts is
