Question: when will scientists be able to uncontaminate land

Christine Switzer answered on 13 Jun 2011:

Hi willchristtmass! Great question!

Some contaminants are easy to remove and others are more complicated. How easy the job is depends on the contaminant and the soil conditions. When we talk about clean-ups, we describe them as site-specific. Something that works well in one site may not work as well in another. Decisions are usually made as a team because many scientists have useful skills to contribute.

The process that my team invented works really well for organics like oils and tars, but is not useful at all for metals like arsenic or lead. We can get soil very clean, so it looks like it has never been contaminated, but we may need to do some extra work afterwards to bring life back into the soils. Other methods may not get to the same pristine condition but can gradually bring life back during a “polishing” step.

With metals especially, sometimes it is not really possible to uncontaminate land. Instead we may try to trap the contaminants within the soil and keep them from coming into contact with people or getting into the groundwater. Or we can build a barrier that reacts with the contaminants so the water gets cleaned as it passes through.

As you can see, there have been a number of useful inventions to clean contaminated land, but I think we still need more.