Is Nanosilver present in these dumped products a threat?

Silver nanoparticles are now the most commonly used nanomaterial in consumer products, according to an inventory listing compiled by the U.S. Woodrow Wilson Center’s Project on Emerging Nanotechnologies. Over 600 products proudly announce their use of nanomaterials, believing it is a marketing advantage.

These include washing machines, kitchenware and food containers, socks, towels and odor-resistant textiles, soaps, cosmetics, toothpaste, the Xbox 360, air filters, teddy bear stuffing, baby products, nutritional supplements, sunscreens and wound dressings.

The nanosilver is used mainly for its antimicrobial properties, but scientists are increasingly concerned that their effects on safety and the environment are not yet fully understood.
 
Silver’s antibacterial properties have been known since ancient times. The Romans kept their wines fresh by placing silver coins in the bottle; they also fixed coins on wounds to minimize infections. Silver was used in wound dressings until the advent of antibiotics. In recent years, silver in the form of nanosilver has regained its popularity as a compound to eliminate bacteria and microbes.

Scientists are concerned that nanosilver present in wash water or in products dumped into landfills will threaten the bacteria and other microorganisms that lie at the base of the entire ecosystem. Every living thing on earth depends on these microorganisms.

For instance, an Arizona State University study found that nanosilver in some socks easily washed off after a few washings. While antimicrobial socks could help some people deodorize their feet or ward off infections, there are unanswered questions about the potential environmental damage.

Some washing machines use silver ions to disinfect clothes (and remove odors) even when unheated water is used. The presence of silver helps reduce the energy requirement and detergent usage for laundry. But all the silver-laden water is flushed down the drain and into wastewater treatment plants, where it has the potential to kill the microbes that process toxic waste into harmless sludge.

Farms sometimes use the sludge from these plants as fertilizer. The silver in the sludge could have an impact on the soil systems, particularly the nitrogen-fixing bacteria inhabiting the soil. All plants depend on these bacteria: kill the nitrogen-fixing bacteria and no crop, no plant will grow.

Undoubtedly, there are benefits derived from using nanosilver. But the basic question remains: do the benefits outweigh the environmental cost and the backlash to humans and other living things?

Silver occurs naturally in the environment, usually in trace amounts. Even in bulk form, silver has been found toxic to fish, algae, crustaceans, certain plants, fungi and bacteria. In the form of nanoparticles, silver poses a more serious threat.

Nanosilver consists of extremely fine particles (1,000 times thinner than human hair). One ounce of nanosilver dust presents a surface area equivalent to one ton of bulk silver. Because they are so tiny, they provide enormous surface area and, for this reason, they are more potent killers of microbes.

Since it eliminates “pests,” the Environmental Protection Agency (EPA) classifies silver as a pesticide, and therefore within its regulatory mandate. Washing machines discharging a lot of silver-laced water may be subject to EPA regulation, but hundreds of other products using nanosilver are not even required to register with the agency.

We thus have a situation where nanosilver — a more useful but also potentially more environmentally threatening form of silver — is at once becoming more ubiquitous and at the same time falling outside the bounds of government regulation.

The National Nanotechnology Initiative Amendments Act of 2008, which will reauthorize government funding for nanotechnology research, was approved by a House science committee last May. It includes a provision for the creation of a Coordinator (in the White House Office of Science & Technology) to oversee the societal dimensions of nanotechnology.

Some scientists believe that is not enough. They tried, but could not convince, the House science committee to earmark 10 percent of the funds authorized in the bill specifically for research on the health, safety and environmental effects of nanotechnology.

There is a wide gap between nanomaterials used in various products and knowledge about their safety. There is as yet no thorough understanding of the possible risks, how to measure them, and how to manage them. And the scientists are not comfortable with that.

Consumers should not, either.

At one time or another, consumers have been inveigled into buying products made out of materials that were supposed to be safe (e.g. tobacco, asbestos, DDT). Much later, these products turned out to be hazardous to health and by then it was too late for many people.

The situation is not that there is a problem with using nanomaterials and nanosilver; rather, it is that we do not know. Shall we allow our congressmen to continue ignoring this issue until once again, it is too late?