A study of the impact of lead in the environment on school children in the Cape Town area

Bibliography: p.124-137.The present study was designed to provide information on lead absorption amongst school children in Cape Town. The primary aim of the study was to determine the degree of lead absorption in part of the community. Further secondary and tertiary aims were to briefly investigate possible sources of lead exposure in children identified with increased lead levels and to determine whether an evidence of behaviour disorder was apparent. The evidence presented in the study suggests that a significant proportion of the population, primarily children living in urban-industrial areas, may have increased lead levels and may be suffering certain metabolic and behavioural impairments due to lead. It is suggested that prudent precautions be taken to limit exposure to lead in the environment

Lead exposure in adult males in urban Transvaal Province, South Africa during the apartheid era

Human exposure to lead is a substantial public health hazard worldwide and is particularly problematic in the Republic of South Africa given the country’s late cessation of leaded petrol. Lead exposure is associated with a number of serious health issues and diseases including developmental and cognitive deficiency, hypertension and heart disease. Understanding the distribution of lifetime lead burden within a given population is critical for reducing exposure rates. Femoral bone from 101 deceased adult males living in urban Transvaal Province (now Gauteng Province), South Africa between 1960 and 1998 were analyzed for lead concentration by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Of the 72 black and 29 white individuals sampled, chronic lead exposure was apparent in nearly all individuals. White males showed significantly higher median bone lead concentration (ME = 10.04 µg·g−1), than black males (ME = 3.80 µg·g−1) despite higher socioeconomic status. Bone lead concentration covaries significantly, though weakly, with individual age. There was no significant temporal trend in bone lead concentration. These results indicate that long-term low to moderate lead exposure is the historical norm among South African males. Unexpectedly, this research indicates that white males in the sample population were more highly exposed to lead

Environmental lead exposure among inner-city Cape Town children : a study of associated risk factors

Bibliography: pages 284-306.Risk factors for lead exposure among children in South Africa have not been well documented. This study elucidated important factors which co-vary with lead in increasing children's risk of exposure. Two study designs were used. First, a cross-sectional analytical study involving first grade school children was executed. Venous blood samples from children were analysed for lead using atomic absorption spectrophotometry. In addition other haematological and anthropometric measurements were conducted. A pre-tested questionnaire administered to parents identified risk factors for lead exposure. Statistical analyses, including log-linear models, were used to determine the relationships between biological, environmental, social factors and blood lead. In an environmental study, daily air and dust samples were collected over a year from several sites in the study area, contemporaneously with the blood and questionnaire surveys. Spatial and temporal variations in atmospheric lead were determined. In stage two a case control study was carried out to determine whether risk factors for lead exposure differed among cases (blood lead ≥ 24 ug/dl) and controls (blood lead ≤ 14 ug/dl). Levels of lead in air, water, paint and dust samples from children's homes were determined and the state of housing evaluated. Home interviews were conducted with parents to assess the role of economic, demographic, cultural, and behavioural factors in increasing children's risk. 13% of coloured children, but no white children were identified with blood lead levels ≥ 25 ug/dl. Air lead levels ranged from 1.5 ug/m³ and dust lead levels from 3 000 ppm. Environmental lead levels were significantly elevated near heavy traffic, particularly during winter months. Baseline exposure was of significance in influencing blood lead levels of children attending schools in direct proximity to heavy traffic, where blood lead levels were elevated. In cases, direct inhalation of aerosols, and ingestion of lead in water were not found to be important risk factors. Hand contamination and mouthing were associated with increased risk. Sources of elevated lead were found in the homes of both cases and controls, but were not accessible in the homes of controls. A conceptual framework for lead exposure in children is proposed, to illustrate how social and environmental factors may act to increase risk. The results have implications for primary and secondary prevention strategies aimed at the community

The role of the South African Medical Research Council in reducing lead exposure and preventing lead poisoning in South Africa

Even at low levels in blood, lead has been associated with reduced IQ scores, behavioural problems, learning impediments, aggression and violent behaviour. Since the 1980s, the South African Medical Research Council (SAMRC) has been investigating the sources of exposure to lead in South Africa (SA), the groups at highest risk of lead poisoning and a selection of the myriad associated health and social consequences. SAMRC research evidence contributed to the phasng out of leaded petrol, restrictions on lead in paint and other interventions. Subsequently, childhood blood lead levels in SA declined significantly. More recent studies have revealed elevated risks of lead exposure in subsistence fishing and mining communities, users of arms and ammunition, those ingesting certain traditional medicines, and users of certain ceramicware and artisanal cooking pots. Lead-related cognitive damage costs the SA economy ~USD17.7 (ZAR261.3) billion annually, justifying further SAMRC investment in lead exposure research in the country

Estimating the burden of disease attributable to four selected environmental risk factors in South Africa

The first South African National Burden of Disease study quantified the underlying causes of premature mortality and morbidity experienced in South Africa in the year 2000. This was followed by a Comparative Risk Assessment to estimate the contributions of 17 selected risk factors to burden of disease in South Africa. This paper describes the health impact of exposure to four selected environmental risk factors: unsafe water, sanitation and hygiene; indoor air pollution from household use of solid fuels; urban outdoor air pollution and lead exposure.The study followed World Health Organization comparative risk assessment methodology. Population-attributable fractions were calculated and applied to revised burden of disease estimates (deaths and disability adjusted life years, [DALYs]) from the South African Burden of Disease study to obtain the attributable burden for each selected risk factor. The burden attributable to the joint effect of the four environmental risk factors was also estimated taking into account competing risks and common pathways. Monte Carlo simulation-modeling techniques were used to quantify sampling, uncertainty.Almost 24 000 deaths were attributable to the joint effect of these four environmental risk factors, accounting for 4.6% (95% uncertainty interval 3.8-5.3%) of all deaths in South Africa in 2000. Overall the burden due to these environmental risks was equivalent to 3.7% (95% uncertainty interval 3.4-4.0%) of the total disease burden for South Africa, with unsafe water sanitation and hygiene the main contributor to joint burden. The joint attributable burden was especially high in children under 5 years of age, accounting for 10.8% of total deaths in this age group and 9.7% of burden of disease.This study highlights the public health impact of exposure to environmental risks and the significant burden of preventable disease attributable to exposure to these four major environmental risk factors in South Africa. Evidence-based policies and programs must be developed and implemented to address these risk factors at individual, household, and community levels

The role of the South African Medical Research Council in reducing lead exposure and preventing lead poisoning in South Africa

Abstract: Even at low levels in blood, lead has been associated with reduced IQ scores, behavioural problems, learning impediments, aggression and violent behaviour. Since the 1980s, the South African Medical Research Council (SAMRC) has been investigating the sources of exposure to lead in South Africa (SA), the groups at highest risk of lead poisoning and a selection of the myriad associated health and social consequences. SAMRC research evidence contributed to the phasng out of leaded petrol, restrictions on lead in paint and other interventions. Subsequently, childhood blood lead levels in SA declined significantly. More recent studies have revealed elevated risks of lead exposure in subsistence fishing and mining communities, users of arms and ammunition, those ingesting certain traditional medicines, and users of certain ceramicware and artisanal cooking pots. Lead-related cognitive damage costs the SA economy ~USD17.7 (ZAR261.3) billion annually, justifying further SAMRC investment in lead exposure research in the country

Factors associated with elevated blood lead levels in inner ·city Cape Town children

A cross-sectional analytical study was carried out to determine risk factors for childhood lead exposure. Blood lead levels of inner-city Sub A coloured children living in Woodstock were examined in relation to information obtained by questionnaire on environmental and social factors. The mean blood lead concentration of the population was 18 ug/dl. Thirteen per cent of children had blood lead levels'≥ 25 ug/dl, the present USA 'action' level. Dusty homes and homes in a poor state of repair, over-crowding, low parental education and income, and other aspects related to family structure and socio-economic status, were associated with raised blood lead levels. It is suggested that social factors assume importance in predisposing children 'to lead in the environment. In particular, the over-crowded nature of the homes could have a direct bearing on the quality of the care-giving environment, providing opportunity for children's activities to go unsupervised. This could lead young children to be more exposed to accessible sources of lead associated with poor housing conditions. More attention needs to be given to examining the interaction of social and environmental factors in studies of childhood lead exposure

Environmental determinants of acute respiratory symptoms and diarrhoea in young coloured children living in urban and peri-urban areas of South Africa

The impact of environmental risk factors associated with housing was examined in relation to diarrhoeal disease and acute respiratory symptoms in South African coloured children. A multistage cluster sample representative of all coloured people living in the major urban and peri-urban areas of South Africa was used for the study. Interviews were conducted with respondents from 1 227 households. Overall, 8,5% children under 5 years were reported to have had diarrhoea, while 29% had experienced coughing and breathing problems in a 2-week recall period. Individual risk factors identified using the odds ratios (ORs) for diarrhoea included not having an inside tap or a flush toilet in the homes (both yielded an OR of 3,3), not owning a refuse receptacle (OR = 2,5), not being connected to an electricity supply (OR = 2,5), low household income (OR = 1,8), more than 2 people per room (OR = 2,0) and less than Standard 5 maternal education (OR = 1,6). Absence of an inside toilet, not having a refuse receptacle and overcrowding all remained as independent risk factors after logistic regression analyses. Multiple logistic regression analyses revealed that not having a refuse receptacle and the absence of electricity for heating purposes were independently associated with respiratory symptoms. The overall preventive potentials for respiratory symptoms were significantly less than those for diarrhoea. Improving physical access to essential environmental health services in urban areas and improvements in the educational status of women are urgently needed if childhood infections are to be prevented