The History of Industrial Lead Contamination: Why Won’t It Go Away?

Lead contamination in the environment, as well as its toxic effects on humans, has been documented for millennia. The earliest sources of that contamination have been attributed to mining and smelting, which released high concentrations of industrial lead into the biosphere and caused acute lead toxicity. Unfortunately, mining and smelting operations still account for large amounts of industrial lead discharged into the environment, in spite of efforts to limit those emissions. Other efforts to reduce industrial lead contamination of the environment have been much more successful, most notably the nearly complete elimination of lead additives in gasoline and the restricted use of lead paint.

Those efforts to reduce industrial lead emissions have been correlated with measurements of reduced lead contamination in the environment – but the environmental and human health effects of industrial lead contamination persist. That persistence is a consequence of the legacy of historic lead contamination and on-going lead contamination. The former includes industrial lead deposited in (1) soils, which is remobilized by winds, erosion, and biogeochemical processes and (2) vegetation, which is remobilized by biogeochemical processes and fires – that are projected to increase dramatically with climate change. The latter includes lead emissions from fossil fuel (i.e., coal) combustion that are now quite large, even though lead concentrations in coal are relatively small, because of the amount of fossil fuel consumption is so great.

As a consequence, lead concentrations in some of the world’s most remote locations are still elevated by inputs of industrial lead. These include lead in the open ocean, polar regions, and some of the least populated terrestrial regions of the Earth. Moreover, that contamination still accounts for elevated lead levels, exceeding national and international human health standards, in some commercial products; and efforts to regulate the amount of lead in those products is complicated by their global origins and markets.