Starting from the Source: Methods and Priorities for Explaining Lead Exposure

Lead is a dangerous neurotoxin, and lead poisoning remains one of the most serious and neglected public health challenges in the developing world, with major negative impacts on global health, education, and overall economic development. There is now growing international momentum to mitigate lead pollution, with the goal of dramatically reducing human lead exposure and consequent adverse effects. Yet before lead exposure can be effectively mitigated, it is essential to understand why humans are being exposed to lead in the first place and therefore how policymakers can intervene to stop further exposure. To date, such research into the major sources of lead exposure—broadly referred to as source assessment—in developing countries has been limited. Thus, there is limited information and no global scientific consensus about the most important causes of global lead exposure. Given growing global interest in addressing lead poisoning, there is an urgent need to better understand the major sources of lead exposure in different settings by increasing the volume and quality of related research. Tailored to a policy audience, this paper offers a state-of-the-science review of methods for doing so. First, it provides background for understanding lead exposure—that is, how and why lead enters the environment, how it behaves once there, and how environmental lead results in elevated blood lead levels for humans. Second, it outlines basic principles for source assessment, including a discussion of objectives and terminology. Third, it details the range of methods available for understanding the sources of lead exposure and describes how such methods can be used in combination to understand major sources of lead exposure in a given context. Finally, it considers major policy-relevant gaps in the literature base about sources of global exposure and offers suggestions for a research agenda in this space.