Lead Pollution : Causes and control

At the time of writing, the topic of lead pollution is the subject of an intense and sometimes heated debate. The argument centres upon possible adverse health effects arising from exposure of children to current environmental levels of lead. Such arguments now appear little closer to resolution than they did five years ago, although the development of ever more sophisticated biochemical and epidemiological techniques may eventually provide an answer. Over the past five to ten years, as the general public has become aware of the lead issue, pressure has been put upon governments to limit emissions of lead, and hence limit or reduce the exposure of the population to the metal. Govern­ ments and governmental agencies have responded in several ways, varying between those who prefer to take little or no action on the basis that they see no cause for concern, and those who have taken firm action after concluding that the scientific and medical evidence warrants this approach. Any effective control strategy for lead requires knowledge of the sources of environmental exposure and an understanding of the pathways of this metal in the environment. This book aims to provide such information and to explain the methods available for limiting emissions of lead from the most important sources. To put this information in context a chapter on the routes of human exposure to lead and the health effects is included.

1 Introduction.- References.- 2 Lead in the atmosphere.- 2.1 Introduction.- 2.2 Sources of lead in air.- 2.1.1 Industrial emissions.- 2.2.2 Fossil fuel combustion.- 2.2.3 Vehicular emissions.- 2.3 Concentrations of lead in ambient air.- 2.3.1 Airborne lead arising from industrial emissions.- 2.3.2 Airborne lead arising from vehicular emissions.- 2.3.2.1 Inorganic lead in air.- 2.3.2.2 Organic lead in air.- 2.3.2.3 Vertical profiles of lead above a street.- 2.3.2.4 Correlation of lead levels with other pollutants.- 2.4 Particle size distributions.- 2.5 Chemical properties of atmospheric lead.- 2.5.1 Smelter emissions.- 2.5.2 Vehicular inorganic lead.- 2.5.3 Organic lead.- References.- 3 Lead in water.- 3.1 Introduction.- 3.2 Sources of lead in surface waters.- 3.2.1 Point sources.- 3.2.1.1 Industrial effluents.- 3.2.1.2 Sewage effluent.- 3.2.2 Diffuse sources.- 3.2.2.1 Urban areas.- 3.2.2.2 Rural areas.- 3.3 Concentrations of lead in water.- 3.3.1 Source waters.- 3.3.2 Receiving waters.- 3.3.3 Ground water.- 3.3.4 Sediments.- 3.3.5 Lead in drinking water.- 3.4 Chemistry of lead in water.- 3.4.1 Solubility control.- 3.4.2 Suspended sediments.- 3.4.3 Organic matter.- 3.4.4 Colloidal hydrous ferric and manganese oxides.- 3.4.5 Mixing with seawater.- 3.4.6 Schemes for the determination of physico-chemical speciation.- References.- 4 Lead in soils.- 4.1 Introduction.- 4.2 Sources of lead in soil.- 4.2.1 Parent materials.- 4.2.2 Dry deposition of airborne lead.- 4.2.3 Wet deposition of airborne lead.- 4.2.4 Disposal of sewage sludge to land.- 4.2.5 Other sources of lead contamination of soils.- 4.3 Concentrations of lead in soil.- 4.4 Uptake of soil lead by living organisms.- 4.5 Chemistry of lead in soils.- 4.6 Lead in street dusts.- References.- 5 Control of lead in air.- 5.1 Industrial sources of lead.- 5.1.1 Mining, smelting and refining of non-ferrous metals.- 5.1.1.1 Primary smelting of lead.- 5.1.1.2 Primary smelting of other metals.- 5.1.1.3 Secondary smelting of lead.- 5.1.1.4 Refining of lead.- 5.1.1.5 Production of ferrous metals and alloys.- 5.1.2 Industrial processes using lead.- 5.1.2.1 Production of lead oxides and pigments.- 5.1.2.2 Storage battery manufacture.- 5.1.2.3 Lead alkyl manufacture.- 5.2 Control of industrial emissions of lead.- 5.2.1 Control of industrial emissions of particulate lead to atmosphere.- 5.2.1.1 Fabric filters.- 5.2.1.2 Electrostatic precipitators.- 5.2.1.3 Inertial collectors.- 5.2.1.4 Wet scrubbers.- 5.2.1.5 Control systems used in the lead industry.- 5.2.2 Control of industrial emissions of organic lead to the atmosphere.- 5.2.3 Chimney heights and dispersion of pollution from a point source.- 5.3 Legislative regulations affecting industrial lead emissions.- 5.3.1 United Kingdom.- 5.3.2 United States.- 5.4 Control of lead emissions from motor vehicles.- 5.4.1 Reduction of the lead content of gasoline.- 5.4.2 Removal of particulate lead from vehicle exhaust gases.- 5.4.3 Lead pollution from waste oil disposal.- 5.5 Ambient air quality standard for lead.- 5.6 Control of lead within the workplace.- 5.6.1 Industrial hygiene standards for lead.- 5.6.2 Monitoring for industrial hygiene.- 5.6.3 Control of lead exposure of workers.- References.- 6 Control of lead discharges to water.- 6.1 Introduction.- 6.2 Water quality criteria and standards.- 6.2.1 Lead in drinking water.- 6.2.2 Lead in freshwaters.- 6.2.3 Sewage works final effluent.- 6.2.4 Industrial effluent.- 6.3 Uniform emission standards versus water quality objectives.- 6.3.1 Water quality objectives.- 6.3.2 Uniform emission standards.- 6.4 Control practices for lead discharges.- 6.4.1 Industrial effluent treatment.- 6.4.1.1 Precipitation.- 6.4.1.2 Activated carbon adsorption.- 6.4.1.3 Ion exchange.- 6.4.1.4 Other removal methods.- 6.4.1.5 Practical experience of lead removal.- 6.4.2 Sewage treatment.- 6.4.3 Stormwater control.- 6.4.3.1 Best management practices.- 6.4.3.2 Structural controls.- 6.4.4 Control of lead in drinking water.- References.- 7 Human exposure to lead and its effects.- 7.1 Introduction.- 7.2 Sources and intake of lead.- 7.2.1 Food.- 7.2.2 Drink.- 7.2.3 Typical daily lead intake from food and drink.- 7.2.4 Lead in air.- 7.2.5 Miscellaneous sources.- 7.3 Uptake of lead.- 7.3.1 Ingestion.- 7.3.2 Inhalation.- 7.3.2.1 Particulate lead.- 7.3.2.2 Tetraalkyllead vapour.- 7.4 Metabolism of lead.- 7.4.1 Inorganic lead.- 7.4.2 Tetraalkyllead.- 7.5 Blood leads.- 7.5.1 Population values.- 7.5.2 Relationship to source of intake.- 7.6 Biological and adverse health effects of exposure to lead.- 7.6.1 Bloodstream.- 7.6.2 Neurobehavioural effects.- 7.6.2.1 The Needleman study.- 7.6.2.2 Conclusions.- References.- 8 Chemical analysis of lead in the environment.- 8.1 Introduction.- 8.2 Chemical analysis of lead: available techniques.- 8.2.1 X-ray fluorescence (XRF).- 8.2.2 Anodic stripping voltammetry (ASV).- 8.2.3 Colorimetric analysis.- 8.2.4 Atomic absorption spectrometry (AAS).- 8.3 Sampling and analysis of environmental media.- 8.3.1 Lead in air.- 8.3.2 Lead in water.- 8.3.3 Lead in soils and sediments.- 8.3.4 Biological materials.- 8.4 Contamination during lead analysis.- References.