A new study has shown that children from the African nation of the Congo have an increased risk of lead exposure from a number of sources that contaminate soil, dust and indoor air. Elevated lead levels were found in almost all children under age 3 and half between ages 3 and 5. More than three times as many city as rural kids had elevated levels. The higher lead levels measured in the youngsters’ blood and the lack of prevention information indicates a widespread public health concern for developing countries. Children in developing countries continue to be exposed to lead levels that are high enough to permanently affect their long-term wellbeing, report researchers who studied exposures in the Democratic Republic of Congo (DRC). Leaded gas, car battery recycling and eating fired clay during pregnancy contributed the most to the high lead levels measured in the children. The findings highlight the extent and magnitude of the problem. Virtually every child under 3 years old and half between the ages of 3 and 5 tested in the study had elevated lead levels. More than three times as many city kids had elevated levels when compared to those living in rural areas. Average concentrations in dust from the children’s homes were more than 60 percent higher than the concentration used in standards for the home environment in the United States. While a prior study reported blood lead levels in the DRC, this study went a step further by determining the prevalence of lead exposures in urban and rural communities and at different ages. Understanding how much and where lead comes from can pave the way for effective public health programs to reduce exposures and their associated health effects. This is important because about 15 to 18 million children in developing countries suffer permanent brain damage due to high exposures to lead. In these areas of the world, basic information about sources and effects of lead exposure is lacking. Lead has wide-ranging health effects that can impact the brain and the nervous, cardiovascular and reproductive systems. Children are particularly vulnerable to its effects because of their rapid growth and development. Very high exposures can be toxic, but recent studies indicate that even low exposures can affect cognition and long-term health. In the United States, the Centres for Disease Control (CDC) recently lowered the level of concern that prompts intervention and community education programs to 5 micrograms per decilitre of blood (?g/dL). During the present study, the researchers measured blood lead levels in 335 people aged 1 to 70 years old in the capital city of Kinshasa and nearby rural areas. They used questionnaires to identify sources of lead exposure in young children. Household dust, soil and air samples were analysed to characterise and pinpoint the childrens lead exposures at home. The researchers report that almost all children younger than 3 and more than half of those between 3 and 5 years old had elevated lead levels. About 71 percent of children had levels above 10 ug/dL CDCs prior level for intervention in the United States and 22 percent had levels above 20 ug/dL – the level at which the CDC recommends medical evaluations. City dwellers had a higher prevalence of elevated blood lead levels than those who lived in the rural communities. Lead dust levels in the homes were up to 26 times higher than those recommended by the U.S. Environmental Protection Agency. Lead from gasoline and car battery recycling contaminated the indoor dust and air, which is breathed in or eaten by children. A third big source of exposure was fired clay, which naturally contains lead. Pregnant women use the clay to treat nausea during pregnancy. Children whose mothers had eaten the clay while pregnant had significantly higher levels of lead in their blood. Elevated blood lead levels in the DRC remain despite the country’s efforts to control lead pollution by phasing out leaded gasoline more than seven years ago. The results suggest that public health education and interventions may be warranted to minimise these exposures.
Environmental Health News, 28 August 2012 ;