Chapter 10
Environmental Fluoride
10.1 INTRODUCTION
Fluorine is the lightest element in Group VII of the periodic table, with the
atomic number 9 and the atomic weight of 18.998. It has a single isotope, and
its valence in all naturally occurring compounds is one. Although fluoride (F) is
not listed as one of the ‘‘Criteria Air Pollutants’’ regulated by U.S.
Environmental Protection Agency, it is nevertheless a very important gaseous
air pollutant. Indeed, F is the most phytotoxic air pollutant because it can
damage plants at extremely low concentrations. Additionally, adverse effects
are not limited to those caused by airborne F: high levels of waterborne F are
also hazardous to both human and animal health. For example, in China and
India millions of people are suffering from dental and skeletal fluorosis –
abnormal or poisoned tooth and bone conditions induced by F – mainly due to
consumption of high levels of F in drinking water.
This chapter begins with an introduction to the sources and forms of F
found in the environment, and then discusses the way in which F influences the
health of plants, animals, and humans. Whenever applicable, reference will be
made to the growing concerns shared by several less-developed countries that
are experiencing significant growth in their economies, such as China and
India.
10.2 OCCURRENCE AND FORMS OF FLUORIDE
10.2.1 INTRODUCTION
Fluoride is ubiquitous: it rarely occurs free in nature, but combines with a
variety of elements to form fluorides that exist in minute amounts in air, water,
minerals and soils, foods, and body tissues. Fluoride found in the environment
is derived from both natural and anthropogenic sources. Natural sources of F
include volcanism, aerosols from ocean spray, and soil particles blown into the
atmosphere, etc., while anthropogenic sources are found mostly in industrial
facilities. Fluoride emitted into the atmosphere from these sources consists of
both gaseous and particulate forms, and as such can contribute F to surface
waters.
[16:52 26/8/04 P:/CRC PRESS/4365 MING-HO.751 (1670)/4365-010.3d]
Ref: 4365 MING-HO YU Chap-010 Page: 149 149-170
149
Environmental Fluoride
10.1 INTRODUCTION
Fluorine is the lightest element in Group VII of the periodic table, with the
atomic number 9 and the atomic weight of 18.998. It has a single isotope, and
its valence in all naturally occurring compounds is one. Although fluoride (F) is
not listed as one of the ‘‘Criteria Air Pollutants’’ regulated by U.S.
Environmental Protection Agency, it is nevertheless a very important gaseous
air pollutant. Indeed, F is the most phytotoxic air pollutant because it can
damage plants at extremely low concentrations. Additionally, adverse effects
are not limited to those caused by airborne F: high levels of waterborne F are
also hazardous to both human and animal health. For example, in China and
India millions of people are suffering from dental and skeletal fluorosis –
abnormal or poisoned tooth and bone conditions induced by F – mainly due to
consumption of high levels of F in drinking water.
This chapter begins with an introduction to the sources and forms of F
found in the environment, and then discusses the way in which F influences the
health of plants, animals, and humans. Whenever applicable, reference will be
made to the growing concerns shared by several less-developed countries that
are experiencing significant growth in their economies, such as China and
India.
10.2 OCCURRENCE AND FORMS OF FLUORIDE
10.2.1 INTRODUCTION
Fluoride is ubiquitous: it rarely occurs free in nature, but combines with a
variety of elements to form fluorides that exist in minute amounts in air, water,
minerals and soils, foods, and body tissues. Fluoride found in the environment
is derived from both natural and anthropogenic sources. Natural sources of F
include volcanism, aerosols from ocean spray, and soil particles blown into the
atmosphere, etc., while anthropogenic sources are found mostly in industrial
facilities. Fluoride emitted into the atmosphere from these sources consists of
both gaseous and particulate forms, and as such can contribute F to surface
waters.
[16:52 26/8/04 P:/CRC PRESS/4365 MING-HO.751 (1670)/4365-010.3d]
Ref: 4365 MING-HO YU Chap-010 Page: 149 149-170
149