Geochemistry

Proceedings of the 30th International Geological Congress, Volume 19

Xie Xuejing

• Publisher: CRC Press
• Year: 2020
• eBook ISBN:
  9781000152852
• Topic: Physical Sciences
• Subtopic: Environmental Science

This book is a collection of papers presented in the 30th International Geological Congress, held in Beijing, on geochemistry. The papers deal with topics on fluid-rock interaction, geochemical kinetics, geochemical mapping, environmental geochemistry, and exploration geochemistry.

ENVIRONMENTAL
GEOCHEMISTRY

Comparative Risk Assessment of Lead Exposure in Birmingham and Shanghai

YONG WANG, IAIN THORNTON, MARGARET E. FARAGO

Environmental Geochemistry Research Group, Centre for Environmental Technology, Royal School of Mines, Imperial College of Science, Technology and Medicine, London SW7 2BP, UK

Abstract

Since the mid 1970s, environmental lead concentrations have declined significantly in most developed countries as a result of successive reductions in lead emissions. Nevertheless, low- level exposure to lead continues to threaten health of vulnerable groups, such as young children. In some developing countries, rapid economic growth and traffic increase have given rise to concern about risk associated with lead in the urban environment. However, until recently, there has been little quantitative information on exposure to lead in these areas. Birmingham, UK and Shanghai, China were chosen to represent different environmental features and provide differences in risks from exposure to lead. Surveys were implemented in and around houses within these cities between 1995 and 1996. In Birmingham, concentrations of lead measured in 85 houses showed a considerable fall over the period from 1984 to 1996. In Shanghai, whilst concentrations of lead in soils and roadside dusts remained relatively lower, elevated concentrations were found in the dusts collected from 65 houses. It was thought that the internal enrichment of lead was mainly due to the use of lead-containing paint in the decoration of floor spaces. The US-EPA Integrated Exposure Uptake Biokinetic (IEUBK 0.99d) lead exposure model for children was validated, updated, and applied to predict blood lead levels and provide comparative assessment of risks. As predicted, health risk has declined significantly in Birmingham over the period 1984-1996, while higher level of lead was predicted in Shanghai’s young children. The results suggested that the reduction of environmental lead in the developing world is of equal importance to that in developed countries.

Keyworth: Birmingham, Shanghai, Risk assessment, Blood lead, Lead concentrations, Model

INTRODUCTION

Lead is one of the earliest metal products and one of the major toxic contaminants in modern environment [6, 22]. Human activities, such as mining and smelting and the use of lead piping, solder, and cable sheathing, have increasingly given rise to concern about human exposure to environmental lead, in particular that of young children [7, 12, 17, 19, 20, 25, 30]. In light of new evidence of potential effects at levels previously believed to be safe, US-EPA and the Centres for Disease Control (CDC) lowered the level of concern for childhood blood lead from 20 μg/dl to 10 μg/dl in 1986 and 1991 respectively [23].

It’s increasingly reported that concentrations of blood lead have declined significantly in most developed counties over the last 20 years [3, 10, 13, 23]. In Britain the annual decrease was estimated as 5% over the period 1976-1984 and a further downward trend followed over the period 1984-1987 [13]. In a very recent health survey of England, blood lead concentrations was estimated to have fallen by a factor of 3.6-5.0 in children since 1984-1987 [10]. In the US, a 37% decline has been reported between 1976 and 1980. In the third national Health and Nutritional Examination Survey between 1988 and 1991, it was shown that mean blood lead concentrations of children aged 1 to 5 years declined 77% (13.7 µg/dl to 3.2 μg/dl) for non-Hispanic white children and 72% (20.2 to 5.6 µg/dl) for non-Hispanic black children [3].

Despite the success of the reduction measures implemented since the mid 1970s, some developed countries have identified fractions of population that continue to exceed national concern levels for lead. In the US, 8.9% children aged 1 to 5 years, or approximately 1.7 million, were estimated to have blood lead levels of 10 µg/dl or greater [3]. In parallel, concentrations of lead in blood in the UK have been found to be significantly higher in men, older people, heavy smokers and drinkers than in other groups, and in certain parts of the UK such as north west England [14]. Exposure to lead at low levels that may adversely affect the health of young children remains a problem, particularly for those who are from low-income families, urban areas, and minorities [3]. Therefore, future efforts in the identification of the vulnerable groups are needed to further reduce lead exposure.

Moreover, lead exposure is likely to increase in the developing countries with rapid economic growth and accelerated traffic. For example, Asian demand for lead increased by a factor of 6 during the last two decades, Asia has now become the third largest and fastest growing lead-consuming region [12]. In China, seventeen preliminary investigations reported elevated blood lead levels in children [18, 28]. It is vital to establish data for lead exposure and identify population at risk in many cities, such as Shanghai, China.

The observed decline in blood lead levels in developed countries has been ascribed to a wide range of measures taken to phase out lead emissions into the environment. The major influence is attributed to the changeover to unleaded petrol. This interpretation, however, lacks data concerning the background of changes in environmental lead which contributes to blood lead via various routes.

Risk assessment models have been increasingly used to predict the likelihood of various unwanted events and adverse effects. Despite numerous methodological uncertainties remaining, risk assessment can provide reasonably accurate predictions of human exposure to lead and relatively accurate estimates of health risk. A program was initiated and designed to provide up-to-date information about differences in the exposure of children to, health risks associated with, lead in the cities of Birmingham in the UK and Shanghai in China. It aims to examine the benefits of the policies for the reduction in emissions of lead from petrol and other sources in Birmingham and provide developing countries with valuable experience in lead reduction. In this study, the US- EPA IEUBK lead model for children (0.99d) [37]...

Table of contents

• Cover Page
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Fluid-Rock Interaction
• Geochemical Kinetics
• Crustal Abundance
• Geochemical Mapping
• Environmental Geochemistry
• Exploration Geochemistry
• Isotope Geochemistry