LEAD AND MATERNAL CHILD HEALTH IN THE GLOBAL SOUTH
NOTE: This document borrows heavily from the Toxicological Profile for Lead, published by the Agency for Toxic Substances and Disease Registry, 2007. Except where noted, the reader can assume that this is the source of any data or facts noted.
Summary prepared by Sandra Page-Cook, MPH; Blacksmith Institute
Widespread exposure to lead can have devastating consequences for communities. The health, cognitive and behavioral effects of elevated blood lead levels can be serious, and cause suffering, excess health costs and loss of productivity, particularly challenging when coupled with the poverty prevalent in the Global South.
Lead mostly enters the body by ingestion, inhalation, or by mother-to-child transmission in-utero or via breast milk. Health effects of lead exposure include cognitive and neurobehavioral deficits, hyperactivity or attention deficit hyperactivity disorder in children, elevated blood pressure, neurobehavioral and neuropsychological effects in adults and encephalopathy, coma and death.
Children exhibit toxicity to lead at lower exposures than adults, and young children are documented to absorb lead more efficiently than adults. Special opportunities for lead exposure during childhood include:
Lead, Pregnancy and Birth: in addition to any active environmental exposure, blood lead levels increase approximately 20 percent during pregnancy in all women. This is the release of bone lead, stored over years of exposure, into the blood. Maternal blood lead freely crosses into the placenta, and infant blood lead levels are on average 19 percent higher than that of their mother at the time of birth. Health effects include the complications of maternal hypertension for mother and fetus, increased risk of miscarriage, preterm birth and low birth weight adjusted for gestational age.
Lead and Birth through Adolescence: infants and young children can be exposed to lead via breast milk or formula prepared with lead contaminated drinking water; crawling and playing on the floor, followed by hand-to-mouth activity; mouthing of objects, and indiscriminate eating of food dropped or found on the floor. Health effects include impaired neurobehavioral and cognitive development and slow growth.
While naturally present in the earth's crust, human use of lead over the past 300 - 400 years has resulted in harmful amounts coming into contact with humans. In 2009, significant sources of excess environmental lead include mining and smelting operations, gun and ammunition factories, and flaking lead based paint. In the Global South, additional sources of exposure include the production of leaded ceramic and pottery glazes and car battery recycling, the biggest use by far.
Blood lead levels are consistently higher in the Global South compared with the Global North, mostly because there are markedly more opportunities for exposure in the Global South, in particular, unsafe car battery recycling. Consisting of 70 percent lead, deteriorated car batteries can be smelted back into usable lead and metal. Formally, businesses buy batteries in bulk to reclaim the lead and other metals. Informally, high unemployment rates along with increased car ownership have lead to the proliferation of small-scale recyclers. In many cases, informal battery melting is a subsistence activity, conducted in homes using archaic melting operations to recover and sell the secondary lead to larger processors. There are many opportunities for exposure during the informal process. Despite efforts by government agencies and the industry to bring safer and more efficient practices into the informal recycling process, ignorance of the risks of lead contamination combined with a lack of viable economic alternatives has led to the systemic poisoning of many poor populations throughout the world. Informal car battery recycling operations are found throughout the Global South, most typically on the outskirts of major urban centers.
While a blood lead level of 10ug/dL remains the CDC's official level of concern (above which health intervention is recommended), it is becoming more apparent blood lead in any amount can impact cognition and behavior. Decreasing IQ across a population has a dramatic effect. Lowering the average as well as the IQ of the least and most intelligent increases the number of people that fall into the category of mildly mentally retarded, hence requiring assistance, as well as decreases the number of high IQ people who generally become the leaders and innovators of society, thus magnifying challenges to alleviating poverty and addressing the myriad health and other concerns that face the poor populations of the world.
The confluence of the large number of lead contaminated homes, and the special susceptibility of children, born and unborn represent a disaster for children of the Global South.
Apart from alleviating suffering caused by lead poisoning, there are additional two key reasons for eliminating known sources of lead exposure in the Global South:
a. It is mostly a discrete problem. That is, fixable with a single infusion of resources and effort. Organizations and governments can then move on to address other issues.
b. Chronic lead exposure contributes to many other health and development challenges.
Addressing exposure to lead in the Global South can yield fundamental and sustained improvements to future health and educational status of the world's most vulnerable communities.
Download pdf of full document; content follows:
1. Executive Summary
2. About Lead
3. How Lead Enters the Human Body
4. Health Effects of Excess Lead Exposure
5. Lead and Maternal Child Health
6. Lead Exposure in the Global North versus the Global South
7. Societal Impacts of Widespread Childhood Lead Exposure
8. The Value of Addressing Lead Exposure in the Global South