You may not always think about it when you do your laundry or flush the toilet; but whatever you eat, wear or apply on your skin ends up in wastewater and eventually reaches the environment. The use of nanoparticles in consumer products like textiles, foods and personal care products is increasing.
What is so special about nanoparticles, is their tiny size: One nanometer is one billionth of a meter. The small size gives nanoparticles unique and novel properties compared to their bigger counterparts and may for example reach locations that bigger particles cannot reach.
Further, pristine nanoparticles behave differently from nanoparticles in the environment. In the environment, nanoparticles are transformed by interacting and forming aggregates with other particles, elements or solids, and thereby obtain other physicochemical properties.
The transformation of these tiny particles in wastewater treatment processes and their effect on freshwater and marine organisms, have largely been unknown.

Increased mortality of marine crustaceans

In a study (“Ecotoxicological Effects of Transformed Silver and Titanium Dioxide Nanoparticles in the Effluent from a Lab-Scale Wastewater Treatment System”) conducted at the Norwegian Institute for Water Research (NIVA), Anastasia Georgantzopoulou and colleagues from NIVA and SINTEF investigated how silver and titanium dioxide nanoparticles behave in wastewater treatment plants, and how marine and freshwater organisms are affected by them.
The researchers made a laboratory-scale wastewater treatment plant, using sludge from a wastewater treatment plant in Norway. They added environmentally relevant concentrations of silver (Ag) and titanium dioxide (TiO2) nanoparticles over a 5-week period and used the treated wastewater to assess the effects of transformed nanoparticles on freshwater and marine organisms, as well as on gill cells from rainbow trout.
The experiment demonstrated contrasting effects on the two crustacean species. For the marine copepod (Tisbe battagliai), mortality increased by 20-45%, whereas exposure to ttreated wastewater did not have any adverse effects on the freshwater crustacean (Daphnia magna).
“These differences are probably due, at least partly, to the two species’ different feeding habits, in combination with the fact that the nanoparticles showed a strong association to solids present in the wastewater”, Georgantzopoulou says…..

Image Credit:  NIVA

Read more at nanowerk.com

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