22/2/2016 - Urgent research is needed to assess the possible risks to human health and ecosystems from the ever-increasing amounts of engineered nanomaterials going into household waste and ending up in the environment, according to a new OECD report.
Nanomaterials in Waste Streams: Current Knowledge on Risks and Impacts says engineered nanomaterials are entering landfill sites, incinerators, and wastewater treatment facilities that are not designed to filter out particles as tiny as a millionth of a millimetre in size. Nanoparticles are thus ending up in sewerage sludge used as agricultural fertiliser and in sewage plant effluent that flows into rivers and lakes, as well as in recycled goods.
Existing research suggests the distinctive properties of nanomaterials – which can more easily penetrate skin and cells than larger compounds – may carry health and environmental risks including cancer causing properties in lungs, toxic effects to the nervous system and antibacterial properties that could harm ecosystems. Despite this, waste containing engineered nanomaterials is disposed of along with conventional waste, with no special precautions or treatment.
“Nanomaterials are revolutionising everyday products, with benefits to society, but there are many unanswered questions about the risks some may pose to our health and the environment,” said OECD Environment Director Simon Upton. “We urgently need a better understanding of these risks so we can assess whether our waste treatment systems should be adapted to contain them.”
Engineered nanomaterials are valued for the novel properties caused by their near-atomic size. The number of products containing them leapt fivefold from 2006 to 2011 as manufacturers used them to improve performance in more than 1,300 products from car tyres and tennis rackets to smartphone batteries, deodorant and hair conditioner.
The report says that while state-of-the-art waste treatment plants may collect a large share of nanomaterials from waste, less efficient processes used in much of the world mean a significant amount is likely released into the environment as exhaust gas from incineration, as ash applied on roads, as treated wastewater or leaches into soil and water sediment.
Most concerning is the existence of nanomaterials in the dried and composted wastewater sludge that is often spread on farmland as fertiliser. In France, for example, half the national wastewater sludge is used for agricultural fertilisation. The potential transformation of engineered nanomaterials in soil, their interactions with plants and bacteria and their transfer to surface water has never been studied in depth.
The report calls for research into the type and amount of nanomaterials entering waste streams, what happens to it inside treatment facilities and the potential impacts of residual waste containing nanomaterials. It recommends greater safety measures for workers at recycling facilities.
The report draws on four case studies contributed by Canada, France, Germany and Switzerland. For further information, or to speak to one of the authors, journalists are invited to contact Catherine Bremer in the OECD Media Office (+33 1 45 24 97 00).
Read more on the OECD’s work on waste
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