A century of hair samples shows how environmental rules helped slash Americans’ lead exposure by up to 100 times.
Before the Environmental Protection Agency was created in 1970, lead pollution was deeply embedded in everyday American life. Communities were exposed through industrial activity, lead-based paint, aging water pipes, and most heavily through vehicle exhaust. Lead is a powerful neurotoxin that builds up in the body over time and has been linked to developmental problems in children. As environmental regulations took effect, lead levels in the environment dropped sharply, followed by a steep decline in human exposure.
The evidence of that change is still visible today.
Hair Samples Reveal a Century of Lead Exposure
University of Utah researchers analyzed hair samples and found dramatic reductions in lead levels stretching back to 1916. These samples provide a long-term biological record of environmental exposure.
“We were able to show through our hair samples what the lead concentrations are before and after the establishment of regulations by the EPA,” said demographer Ken Smith, a distinguished professor emeritus of family and consumer studies. “We have hair samples spanning about 100 years. And back when the regulations were absent, the lead levels were about 100 times higher than they are after the regulations.”
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