Scientists have developed tests sensitive enough to detect and measure microscopic particles of coal ash in soil, even at concentrations so low and sizes so small that other tests would likely miss them. The four new tests complement tests previously developed at Duke to detect coal ash contamination in water and larger particles of coal ash in soil.

The tests are specifically designed to analyze soil for the presence of fly ash particles so small other tests might miss them.

Fly ash is part of coal combustion residuals (CCRs) that are generated when a power plant burns pulverized coal. The tiny fly ash particles, which are often microscopic in size, contain high concentrations of arsenic, selenium and other toxic elements, many of which have been enriched through the combustion process.

While the majority of fly ash is captured by traps in the power plant and disposed to coal ash impoundments and landfills, some escapes and is emitted into the environment. Over time, these particles can accumulate in soil downwind from the plant, potentially posing risks to environment and human health.

«Because of the size of these particles, it’s been challenging to detect them and measure how much fly ash has accumulated,» said Avner Vengosh, Distinguished Professor of Environmental Quality at Duke’s Nicholas School of the Environment. «Our new methods give us the ability to do that — with high level of certainty.»

Coal combustion residuals are the largest industrial solid wastes produced in the United States. When soil contaminated with fly ash is disturbed or dug up, dust containing the ash can be transported through the air into nearby homes and other indoor environments. Inhaling dust that contains fly ash particles with high levels of toxic metals has been linked to lung and heart disease, cancer, nervous system disorders and other ill effects.

Story Source: Materials provided by Duke University. Note: Content may be edited for style and length.