Lead exposure dropped over the last century, hair study suggests

Researchers analyzed hair samples from 48 Utah residents dating back to 1916 and found lead concentrations were much higher before the EPA's 1970 regulations, with a steep decline in levels after that period.

Researchers published a study in PNAS that used hair clippings to track lead exposure across roughly 100 years. The team analyzed 48 samples from Utah residents, including some taken from scrapbooks, and measured elemental concentrations with mass spectrometry. The study focuses on the Wasatch Front, a region with historical industrial smelting that largely closed by the 1970s. The researchers reported much higher lead levels before the U.S. Environmental Protection Agency was established in 1970 and a pronounced decline in hair lead concentrations afterward. Key findings: - The dataset included 48 hair samples spanning about a century, with some samples dating to 1916. - Scientists used mass spectrometry to measure lead in hair; hair records environmental exposure over time but does not directly equal internal blood concentrations. - Reported lead concentrations were about 100 times higher before EPA-era regulations than after those regulations were in place. - Measured values peaked near 100 parts per million (ppm), fell to about 10 ppm by 1990, and were below 1 ppm in more recent decades. - The Wasatch Front had a history of smelting; most of the region's smelters closed by the 1970s, which the authors note is part of the local exposure context. Summary: The study's measurements align with historical reductions in lead use in gasoline, paint, and pipes that followed EPA-era regulation and show a steep fall in environmental lead recorded in hair samples after the 1970s. Undetermined at this time.