Nanotech for clean water: New technology, new rules?

Emerging nanotech for purifying water at this stage should be regulated with existing laws, say Malini Balakrishnan and Nidhi Srivastava.

Around the world, dwindling water supplies and deteriorating water quality are driving innovations in water treatment technologies. Nanotechnology is a key player since it can improve applications ranging from large-scale seawater desalination systems to community based arsenic removal units to household water filters.

Because of nanoparticles’ special properties and potential applications in energy, health and agriculture, advocates of nanotechnology sometimes perceive it as a ‘silver bullet’ that will fix a spectrum of development problems.

Others argue that nanomaterials may be the next asbestos, with unknown health and environmental impacts,and that they should be strictly regulated. Such concerns are particularly relevant for developing countries, which have large potential marketsfor nanotechnology-based water treatment but may not have the capacity to cope with any unforeseenadverse effects. New regulations might seem the obvious answer, but we should look before we leap.

There is also anxiety over how used filters and media containing nanomaterials might affect the environment. If nanotechnology becomes widely used, the disposal of nanomaterials will be difficult to contain, especially where they are used in household and community-level applications. The situation would be akin to mobile phones. Unless the supplier takes responsibility for collecting and managing used nano-based products — for example while servicing water treatment systems — the material will most likely end up in local dumpsites and landfills.

Unsuspecting developing countries could suddenly face a completely new set of pollution problems. In water purification applications, the nanomaterial is typically coupled to, or embedded in, other materials like filters that keep it trapped. But this may not always be the case. For example, silver nanoparticles used as odour neutralisers in fabrics have been known to leach after soaking in water.

If nanomaterials find their way into water bodies, they could affect population and food dynamics, harming aquatic life. Studies in the United States have shown that if nanoparticles end up in sewage sludge subsequently used as fertiliser, they could damage plant growth.

First, we don’t yet know the full risks of using nanotechnology to purify water, so regulating for them is difficult and fixed rules might quickly become defunct as new risks arise. Regulation of nanotechnology in its broader senseis still in its infancy — usually emerging as a reaction to fast-paced technological developments. While risks are still being identified and defined, our priority should be to ensure that existing regulations have the flexibility needed to address new threats as and when they become known.

The regulatory regime for water treatment must anyway be flexible enough to cope with all concerns — whatever the technology or raw materials used. Imagine that we carve out a separate set of regulations for nanotechnology in water purification. Tomorrow, if a new technology with new properties is developed for treating water, we would need a whole new set of regulations. Such short sightedness would restrict the law’s ability to respond to new and emerging risks, and also create administrative overlaps.

Creating new rules for nanotechnology in water treatment is also undesirable for a more practical reason. Water treatment as a whole encompasses a number of different aspects, including treatment schemes, supply networks and waste disposal. Most of these are already governed by multiple government bodies and regulations. For example, in India, waste management is governed by hazardous materials rules, municipal solid wastes rules, and the Water Pollution Act. Adding new regulations to this list, for instance to control how filters containing nanomaterials are disposed of, will do little beyond creating confusion. Moreover, micro-segregation of waste would be difficult due to overlapping rules.

For example, requirements for labelling that indicates the quantity and type of nanomaterials used in any product,and recognising waste containing nanomaterials as potentially hazardous, can help people take adequate precautions when handling and disposing of these. Similarly, standards for permissible limits of different substances in drinking water can be updated to reflect the concerns around nanotechnology.

Fostering policymakers‘ and regulators’ will and capacity to understand and address the challenges of nanotechnology is more important than new regulation. Greater inter-ministry and department coordination, information exchange and capacity building is needed. After all, any regulation is only as good as the sincerity and success of its implementation.

Malini Balakrishnan is a bio-chemical engineer and Nidhi Srivastava is a lawyer. Both work at the Energy and Resources Institute (TERI), New Delhi, India. These are their personal comments. The authors acknowledge the IDRC supported project on capability, governance, and nanotechnology developments in India that provided the background for this article.