Nanoparticles negative impact

For years, scientists have known about silver’s ability to kill harmful bacteria and, recently, have used this knowledge to create consumer products containing silver nanoparticles.

Now, a University of Missouri researcher has found that silver nanoparticles also may destroy benign bacteria that are used to remove ammonia from wastewater treatment systems.

Several products containing silver nanoparticles already are on the market, including socks containing silver nanoparticles designed to inhibit odour-causing bacteria and energy-efficient washing machines that disinfect clothes by generating the tiny particles. The positive effects of that technology may be overshadowed by the potential negative environmental impact.

’Because of the increasing use of silver nanoparticles in consumer products, the risk that this material will be released into sewage lines, wastewater treatment facilities, and, eventually, to rivers, streams and lakes is of concern,’ said Zhiqiang Hu, assistant professor of civil and environmental engineering in MU’s College of Engineering. ’We found that silver nanoparticles are extremely toxic. The nanoparticles destroy the benign species of bacteria that are used for wastewater treatment. It basically halts the reproduction activity of the good bacteria.’
 
Hu said silver nanoparticles generate more unique chemicals, known as highly reactive oxygen species, than do larger forms of silver. These oxygen species chemicals likely inhibit bacterial growth. For example, the use of wastewater treatment “sludge” as land-application fertiliser is a common practice, according to Hu. If high levels of silver nanoparticles are present in the sludge, soil used to grow food crops may be harmed.