Control of Lead Sources in the United States, 1970-2017: Public Health Progress and Current Challenges to Eliminating Lead Exposure

Abstract

Context: During the past 45 years, exposure to lead has declined dramatically in the United States. This sustained decline is measured by blood and environmental lead levels and achieved through control of lead sources, emission reductions, federal regulations, and applied public health efforts.

Objective: Explore regulatory factors that contributed to the decrease in exposure to lead among the US population since 1970.

Design/setting: We present historical information about the control of lead sources and the reduction of emissions through regulatory and selected applied public health efforts, which have contributed to decreases in lead exposure in the United States. Sources of lead exposure, exposure pathways, blood lead measurements, and special populations at risk are described.

Results: From 1976-1980 to 2015-2016, the geometric mean blood lead level (BLL) of the US population aged 1 to 74 years dropped from 12.8 to 0.82 μg/dL, a decline of 93.6%. Yet, an estimated 500 000 children aged 1 to 5 years have BLLs at or above the blood lead reference value of 5 μg/dL established by the Centers for Disease Control and Prevention. Low levels of exposure can lead to adverse health effects. There is no safe level of lead exposure, and child BLLs less than 10 μg/dL are known to adversely affect IQ and behavior. When the exposure source is known, approximately 95% of BLLs of 25 μg/dL or higher are work-related among US adults. Despite much progress in reducing exposure to lead in the United States, there are challenges to eliminating exposure.

Conclusions: There are future challenges, particularly from the inequitable distribution of lead hazards among some communities. Maintaining federal, state, and local capacity to identify and respond to populations at high risk can help eliminate lead exposure as a public health problem. The results of this review show that the use of strong evidence-based programs and practices, as well as regulatory authority, can help control or eliminate lead hazards before children and adults are exposed.

Figure 1:

Selected Lead Control Measures, United States, 1970-2012

Figure 2.. Consumption of Leaded Gasoline and Average Air Lead Concentrations, U.S., 1975-2016

Note: Air lead concentration data are based on 122 ambient air quality monitoring stations during 1977-79, 216 stations during 1980-89, 175 stations during 1990-2000, 125 stations during 2001-2009, and 108 stations during 2010-2016. The increase in air lead concentration between 2000 and 2001 is likely due to changes at sites near stationary industrial sources. The decline in air lead concentrations between 2001 and 2002 is likely due to lower lead concentrations at sites in Herculaneum, Missouri. Sources: personal communication, Jim Caldwell, USEPA, 1996; USEPA, 1998; USEPA, 2001; USEPA, 2003; USEPA, 2018 (https://www.epa.gov/air-trends/lead-trends)