Montana Earth Science Picture of the Week

This three photos on this page show the yard replacement program that took place in East Helena to remove soils that had been contaminated with lead (also arsenic and cadmium).

Mistakes of the past . . .
For more than 100 years emissions from the ASARCO Lead Smelter caused lead to be deposited in the soils of East Helena. Microscopic lead particles were released from the tall stacks that stood on the smelter property until 2009. At the smelter, which closed in the late 1990s, tall stacks were used to put the pollution higher into the atmosphere where winds would carry it away and spread it out more. Unfortunately, a significant amount of lead ended up falling in the community of East Helena where it became part of the soil. As children played they may have inhaled some of the dust (including lead particles). Some of the lead would dissolve in the moisture in their lungs where it would be absorbed into their blood.

In 1984 East Helena was added to the EPA's (Environmental Protection Agency) Superfund Priorities List. Superfund sites are places that must be cleaned up because they pose a risk to human health and/or the environment.

Lead in the bodies of children . . .
Testing in 1975 indicated that children in East Helena had elevated levels of lead in their blood as result of inhaling dust from lead-contaminated soils. During the clean-up, which took place mostly in the 1990s, soil from over 700 yards was replaced. The soil replacement program continued to take place as children moved into houses where soils were contaminated.

Above Right: First, the soil was removed to a depth of about 6 inches. Below Left: New topsoil was brought in. Below Right: Finally, sod was placed on top of the new soil.