The threat of nanoparticles in the environment takes a new twist. A report from researchers at the admirable Project on Emerging Nanotechnologies (PEN) at the Woodrow Wilson International Center for Scholars in Washington, DC, assesses the use of free nanomaterials as clean-up agents for contaminated land (pdf of the report here).

The science makes sense – to clean up contaminated land, reactive nanoparticles can be injected underground and because of their tiny size should be able to penetrate places where other particles can’t reach. Nanoparticles can have their outer shells tagged with reactive chemical groups to start reactions that break down toxic waste.

According to PEN’s press release, “Most of the materials discussed are a form of nano-scale zero-valent iron that are injected into the ground in a slurry which provide a reducing environment that enables the breakdown of contaminants.”

But the message we’ve been getting from those concerned about regulation for many years is that until the long terms potential risks of these teeny particles are known it is irresponsible to allow them to be released into the environment.

This latest report doesn’t offer the answer, merely highlights the pros and cons of such a system. But nanoremediation, as it is called, is already being used across parts of the world, particularly in the United States. To accompany the review article, Nanotechnology and in situ remediation: a review of the benefits and potential risks by Barbara Karn, Todd Kuiken and Martha Otto from PEN and the US Environmental Protection Agency (EPA), PEN has produced a map showing the 45 known sites where nanoremediation is already being used.

Apparently, a 2004 EPA report but the price tag at $250 billion to clear up the US’s hazardous waste sites, and operation they estimate will take 30 – 35 years. “Nanoremediation has the potential not only to reduce the overall costs of cleaning up large scale contaminated sites, but it also can reduce cleanup time, eliminate the need for treatment and disposal of contaminated dredged soil, reduce some contaminant concentrations to near zero, and can be done in situ,” says the PEN website.

The bottom line remains, though that until the impact of using these nanoparticles is assessed and understood they shouldn’t be used on a large scale. And proper large-scale testing of the technology is what the report recommends should be the next step. Report author Todd Kuiken: “Despite the potentially high performance and low cost of nanoremediation, more research is needed to understand and prevent any potential adverse environmental impacts, particularly studies on full-scale ecosystem-wide impacts. To date, little research has been done.”