For years, scientists have known about silver's ability to kill harmful bacteria, and recently they have used this knowledge to create consumer products that contain silver nanoparticles. The study, funded by the National Science Foundation, was recently published in the journal Water Research and Environmental Science & Technology.
There are already several products on the market that contain silver nanoparticles, including socks that contain this type of nanoparticle to eliminate bacteria that cause bad odor; and high-tech, low-power washers that disinfect clothes by generating these tiny particles. Worse, the positive effects of this technology could be clouded by its possible negative impact on the environment.
“Due to the increasing use of silver nanoparticles in consumer products, the risk of this material being released into sewage lines and sewage treatment facilities and eventually reaching rivers, streams and lakes It's worrying, ”said Zhiqiang Hu, assistant professor of civil and environmental engineering at the University of Missouri School of Engineering. “We have discovered that silver nanoparticles are extremely toxic. The nanoparticles destroy the benign species of bacteria used to treat wastewater. Basically, they slow down the reproductive activity of the good bacteria. "
According to Hu, the silver nanoparticles generate more unique chemicals, known as reactive oxygen species, that produce larger forms of silver. These substances probably inhibit bacterial growth. For example, using sewage treatment “sludge” as fertilizer for soil is common practice, Hu says. If there is a high presence of silver nanoparticles in the sediment, the soil used to grow food crops could be contaminated.
Hu is launching a second study to determine at what levels the presence of silver nanoparticles becomes toxic. With this study, you will determine how silver nanoparticles affect wastewater treatment processes as the nanomaterial is introduced into wastewater and sludge. It will then measure microbial growth to determine the levels of nanosilver that impair wastewater treatment and sludge digestion.
Source: University of Missouri