Protecting our food from mercury contamination

One size does not fit all when it comes to using biochar for soil remediation, according to researchers who used the Canadian Light Source (CLS) at the University of Saskatchewan.

Mercury is used in a variety of industries, including textile manufacturing and gold and silver mining. When released into the environment, this highly toxic element causes widespread contamination of soil. As mercury enters rivers, lakes and oceans, it is converted to methylmercury, a neurotoxin that moves into the food chain through fish and seafood, posing a serious risk to human health.

Conventional methods of remediating mercury-contaminated soil – such as adding activated carbon – can be quite expensive to apply on a large scale. However, recent research has found that biochar, a charcoal produced by superheating agriculture or forestry waste in the absence of oxygen, holds promise as a low cost, “green” alternative.

Read more on the Canadian Light Source website

Image: The experimental set-up. Credit: Canadian Light Source

Plant roots police toxic pollutants

X-ray studies reveal details of how P. juliflora shrub roots scavenge and immobilize arsenic from toxic mine tailings.

Working in collaboration with scientists at the U.S. Department of Energy’s Brookhaven National Laboratory and SLAC National Accelerator Laboratory, researchers at the University of Arizona have identified details of how certain plants scavenge and accumulate pollutants in contaminated soil. Their work revealed that plant roots effectively “lock up” toxic arsenic found loose in mine tailings—piles of crushed rock, fluid, and soil left behind after the extraction of minerals and metals. The research shows that this strategy of using plants to stabilize pollutants, called phytostabilization, could even be used in arid areas where plants require more watering, because the plant root activity alters the pollutants to forms that are unlikely to leach into groundwater.

The Arizona based researchers were particularly concerned with exploring phytostabilization strategies for mining regions in the southwestern U.S., where tailings can contain high levels of arsenic, a contaminant that has toxic effects on humans and animals. In the arid environment with low levels of vegetation, wind and water erosion can carry arsenic and other metal pollutants to neighboring communities.

>Read more on the National Synchrotron Light Source II (NSLS-II) website

Image: Scientists from the University of Arizona collect plant samples from the mine tailings at the Iron King Mine and Humboldt Smelter Superfund site in central Arizona. X-ray studies at Brookhaven Lab helped reveal how these plants’ roots lock up toxic forms of arsenic in the soil.
Credit: Jon Chorover