Fluoride in Drinking Water

by K. Bailey, 3. Chilton, E. Dahi, M. Lennon and P. Jackson

World Health Organization Geneva 1999

CONTENTS

1. FOREWORD

2. FLUORIDE OCCURRENCE, GEOCHEMISTRY AND EXPOSURE

2.1 Occurrence and Chemistry

2.2 Fluoride Distribution in Water

2.3 Exposure

2.4 References

3. ASSESSMENT OF HUMAN HEALTH RISKS OF FLUORIDE

3.1 Fluoride Metabolism

3.2 Effects on Laboratory Animals and in vitro systems

3.3 Effects on humans

3.4 References

4. BENEFICIAL USE

4.1 Introduction

4.2 Dental effects of fluoride naturally present

4.3 Adjustment of fluoride level

4.4 Fluoridated toothpaste against a background of water fluoridation

4.5 Medical issues related to water fluoridation

4.6 References

5. GUIDELINES AND STANDARDS

5.1 Derivation of WHO Guideline Value

5.2 Application of WHO Guideline Value to Local Conditions

5.3 References

6. REMOVAL OF EXCESSIVE FLUORIDE

6.1 Introduction

6.2 Method Characterisation

6.3 Bone Charcoal

6.4 Contact Precipitation

6.5 Nalgonda

6.6 Activated Alumina

6.7 Clay

6.8 Evaluation and Selection of Method

6.9 References

7. ARTIFICIAL FLUORIDATION

7.1 Purpose and scope

7.2 Objectives of fluoridation

7.3 Fluoridation chemicals

7.4 Preparation and storage systems

7.5 Dosing systems

7.6 Point of treatment

7.7 Monitoring and control

7.8 Other issues

7.9 References

 

LIST OF TABLES

Table 4.1 The experience of dental decay among four-year-old children in

Grand Rapids, Muskegon and Aurora from 1944 to 1951. Table 4.2 The experience of dental decay among four-year-old children in

Kilmarnock and Ayr from 1956 to 1968. Table 6.1 Differences in characterisation of water treatment methods in

conventional systems as taking place in industrialised and

developing countries

Table 6.2 Critical parameters for bone charcoal preparation and quality testing Table 6.3 Comparison of the three types of bone charcoal filters illustrated in

Figure 6.1 Table 6.4 Examples of design of the bone charcoal filters illustrated in

Figure 6.1 Table 6.5 Examples of design of domestic and school brick-built plants for

contact precipitation of fluoride. Table 6.6 Some defluoridation unit prices of an NGO development project 'in

India Table 6.7 Examples of design of bucket flocculation as illustrated in Figure 6.1

and an up flow column filter illustrated in Figure 6.7 Table 6.8 General comparison of advantages of the most promising

defluoridation methods Table 7.1 Fluoridation chemicals

LIST OF FIGURES

Figure 6.1 Three most common domestic units for sorption defluoridation Figure 6.2 Contact precipitation for household use Figure 6.3 Contact precipitation of fluoride as invented in Ngurdoto Figure 6.4 The Nalgonda defluoridation as adopted for domestic use in

Tanzania Figure 6.5 The fill and draw type Nalgonda technique for domestic and

community defluoridation

Figure 6.6 Diagram of the Nalgonda process as installed in Tanzania Figure 6.7 A user friendly and technically advanced set-up of the sorption

defluoridation

Figure 6.8 Brick chips columns as used in Sri Lanka Figure 7.1 Schematic fluoridation plant Figure 7.2 Simplified process control scheme