Preface

The subject of fluoride has been studied extensively by scientists around the globe. The current interest in fluoride science has, however, arisen in the context of the ongoing climate change scenarios that have aggravated fluoride pollution of natural resources, especially surface and groundwater resources and agricultural soils, with far-reaching impacts on ecosystems, public health, and water and food security.

Although significant gaps remain in the primary data on the current topic, large volumes of research data are continuously being added to the knowledge of environmental fluoride. There is a growing desire among the scientific community to consolidate the present knowledge with a view to improving a broad understanding of the global fluoride problem. A number of review papers have been published on fluoride environmental pollution, its public health impacts, and remediation and amelioration strategies. The present volume aims to contribute to the consolidation of this knowledge and improve its accessibility.

The book is therefore based on the case-study model, aiming to present, logically and concisely, selected works on various aspects of the subject of fluoride, including its occurrence and environmental sources, natural contamination, human exposure, its impacts, and their amelioration. It is hoped that readers will find this volume useful for enriching and advancing their understanding of the subject.

> **Enos Wamalwa Wambu, Grace J. Lagat and Ayabei Kiplagat** Department of Chemistry and Biochemistry, University of Eldoret, Eldoret, Kenya

**1**

**Chapter 1**

**Abstract**

Yemen Regime

*Abdulmohsen Alamry*

Origin and Hydrogeochemistry

of Fluoride in the Context of the

Groundwater is a natural resource that is used in a variety of fields, which has an impact on its quality. In many places of the world, fluoride-enriched water has become a major public health concern. It is necessary to investigate the geochemical mechanism of fluoride enrichment in drinking water. In Yemen, groundwater is the only supply of water, and its quality is critical because it determines the groundwater's usefulness for drinking and other domestic purposes. The primary goal of this chapter is to gain a better understanding of factors that influence high fluoride levels in groundwater and its impacts from selected parts of Yemen. The elevated ion concentrations in groundwater are most likely due to water-rock interaction, according to the regional hydrogeochemical investigation. The main findings of this review indicate that the children in the area who get their drinking water from wells with high fluoride levels are suffering from dental and skeletal fluorosis. The population in the research area is at high risk due to excessive fluoride intake, particularly in the

absence of knowledge about quantity of fluoride consumption.

rock-water interaction, fluorite, Yemen

continual interfacial reactivity of water with rocks.

**1. Introduction**

**Keywords:** hydrogeochemistry, fluorosis, fluoride contamination, volcanic rocks,

Groundwater's chemical composition is obtained from a variety of sources of solutes, including gases and atmospheric aerosols, below-surface replacement and precipitation reactions, weathering and erosional activities of soils and rocks, and other anthropogenic effects. The study of water chemistry can reveal a lot about the geological history of rocks as well as the velocity and direction of water flow [1]. Groundwater's chemical, physical, and bacteriological properties determine its suitability for municipal, commercial, industrial, agricultural, and domestic use [2]. To understand an aquifer's hydrogeochemistry, a detailed understanding of the rock-water interactions that influence groundwater chemical composition is required. The mineral composition of the rock is the primary component that governs a location's water chemistry [3]. The local regime differs from other sites due to the
