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Nanotech: A history lesson

We're living in a chemical soup, exposed to multiple hazards that we cannot see, hear or feel. Ecosystems are also suffering from this recipe of human-made materials. Historically, our response to chemical hazards--whether as ingredients or mixtures--has been slow at best.

It took 30-plus years to ban DDT since its first use as a pesticide. And pollution continues to seep into the water from the Bhopal disaster, which happened more than a quarter-century ago at a pesticide plant in India. Lawsuits associated with that tragedy are still pending.

Lack of political will, economic agendas, and uncertainties over environmental risk assessment are among the challenges to addressing environmental pollution before it's too late. Now, history seems to be repeating itself with the newest addition to the soup mix: engineered nanomaterials (ENMs).

Nanotechnology involves the manipulation of matter at the atomic scale, 1 to 100 nanometers (1 billionth of a meter), to create new products and processes with novel properties. It's being used in material engineering, consumer products, food production, agriculture, health care, environmental remediation and medicine.

Many portray nanotechnology as today's greatest revolutionary force. More than a thousand consumer products currently on the market contain nanomaterials, from dental fillers, fuel cells and tires to electronics, clothing and cosmetics. Nanotechnology could help improve human drugs, pesticide delivery, renewable energy systems, and the quality and safety of food.

At the nanoscale, matter takes on increased reactivity, unique electrical and physical properties, and the ability to penetrate biological and environmental systems. Some of these properties can be harnessed for environmental benefit. Superfund sites, where hazardous waste is located, are being remediated with iron nanoparticles. In addition, solar cells developed with ENMs are proving to be more efficient with the use of fewer materials.

However, these special properties also allow nanoparticles to cross the blood-brain barrier in the central nervous system, among other physical separations in organisms. And nano-versions of existing chemicals are more toxic to animals at lower concentrations than their larger cousins.

In other words, nanotechnology presents a double-edged sword. While it has potential to benefit society, it also has potential to increase risk.

The United States has yet to see a coordinated approach to environmental regulation of ENMs, even though their manufacturing, use and disposal have occurred for more than a decade. Our laws and regulatory processes are not designed to capture nano-versions of existing products. Moreover, there's little information on where nanomaterials are produced or in what quantities. No mandatory reporting requirements exist. There is also little pre-market testing for the ENMs used in most products.

Washing machines with silver nanoparticles illustrate just one crack in the regulatory system. The machines allow clothes to last longer without smelling (i.e. bacterial growth is prevented by the particles), but the associated ENMs end up in surface and ground water--despite the fact that their toxicity to microorganisms has already been established.

After intense pressure from non-governmental organizations, the U.S. Environmental Protection Agency is just now starting to consider the regulation of silver ENMs as pesticides. But if the manufacturer does not claim that the product is a pesticide, the regulatory process is not triggered. For example, some silver ENM products are now marketed as "fresher longer" instead of germ-killing.

To date, about only 1 percent of federal government spending on nanotechnology research has been devoted to environmental risk-relevant research. A new bill to increase this percentage has been drafted, but has yet to pass the House and Senate.

At the same time, laboratory studies on the toxicity of ENMs to several indicator organisms are accumulating. Bans on the most toxic ENMs, such as certain carbon nanotubes with asbestos-like properties, should be considered until more studies are gathered and interpreted.

These bans may not be purely "science-based" decisions, in the sense that the damage hasn't been explicitly seen, at least not yet. Considering our history of chemical usage and environmental impacts, a cautious approach makes sense. Given its "newness," nanotechnology presents an opportunity for us to do better this time.

- Associate Professor Jennifer Kuzma

(Reprinted from the Institute on the Environment's Momentum magazine.)

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