The European Commission’s environmental news service is edited by the University of the West of England. In Issue 482 they reported on another piece of research into the impact of nanosilver.
Silver nanoparticles are increasingly being used in household products, including appliances. But concern about their eventual release into the wild, particularly via waste water treatment plants, has prompted various research projects.
The recent study looked at silver nanoparticles in sewage sludge which was treated and then applied to soil from agricultural land from Queensland (Australia).
The researchers found that almost all the silver added to the sludge reactors stayed in the sludge, most of it being converted to silver sulphide which is stable in soil and has a low availability to plants which diminishes over time. They also found that the bioavailability of silver increased considerably in soils with higher levels of chlorine, though this did not seem to affect plant growth.
The study concludes that silver nanoparticles entering soils via sewage sludge pose a low risk to plants, but their bioavailability (and, therefore, risk) might increase in saline soils (of which there are over 20 million hectares in Europe) or those irrigated by poor-quality water (which might include chlorine).
Still on nanoparticles, a recent report from the Institute of Occupational Medicine expressed concern about the OECD’s dossiers on manufactured nanomaterials being used for regulatory risk assessment purposes.
The European Commission is currently preparing to include nanomaterials in annexes to the REACH Regulation.