Engineered nanomaterials (ENM) are already used in many products and consequently released into environmental compartments. In this study, we calculated predicted environmental concentrations (PEC) based on a probabilistic material flow analysis from a life-cycle perspective of ENM-containing products. We modeled nano-TiO(2), nano-ZnO, nano-Ag, carbon nanotubes (CNT), and fullerenes for the U.S., Europe and Switzerland. The environmental concentrations were calculated as probabilistic density functions and were compared to data from ecotoxicological studies. The simulated modes (most frequent values) range from 0.003 ng L(-1) (fullerenes) to 21 ng L(-1) (nano-TiO(2)) for surface waters and from 4 ng L(-1) (fullerenes) to 4 microg L(-1) (nano-TiO(2)) for sewage treatment effluents. For Europe and the U.S., the annual increase of ENMs on sludge-treated soil ranges from 1 ng kg(-1) for fullerenes to 89 microg kg(-1) for nano-TiO(2). The results of this study indicate that risks to aquatic organisms may currently emanate from nano-Ag, nano-TiO(2), and nano-ZnO in sewage treatment effluents for all considered regions and for nano-Ag in surface waters. For the other environmental compartments for which ecotoxicological data were available, no risks to organisms are presently expected.

The aim of this study was to use a life-cycle perspective to model the quantities of engineered nanoparticles released into the environment. Three types of nanoparticles were studied: nano silver (nano-Ag), nano TiO2 (nano-TiO2), and carbon nanotubes (CNT). The quantification was based on a substance flow analysis from products to air, soil, and water in Switzerland. The following parameters were used as model inputs: estimated worldwide production volume, allocation of the production volume to product categories, particle release from products, and flow coefficients within the environmental compartments. The predicted environmental concentrations (PEC) were then compared to the predicted no effect concentrations (PNEC) derived from the literature to estimate a possible risk. The expected concentrations of the three nanoparticles in the different environmental compartments vary widely, caused by the different life cycles of the nanoparticle-containing products. The PEC values for nano-TiO2 in water are 0.7--16 microg/L and close to or higher than the PNEC value for nano-TiO2 (< 1 microg/L). The risk quotients (PEC/PNEC) for CNT and nano-Ag were much smaller than one, therefore comprising no reason to expect adverse effects from those particles. The results of this study make it possible for the first time to carry out a quantitative risk assessment of nanoparticles in the environment and suggest further detailed studies of nano-TiO2.

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Not much is known so far about the amounts of engineered nanomaterials (ENM) that are produced but this information is crucial for environmental exposure assessment. This paper provides worldwide and Europe-wide estimates for the production and use of ten different ENM (TiO 2 , ZnO, FeO x , AlO x , SiO 2 , CeO 2 , Ag, quantum dots, CNT, and fullerenes) based on a survey sent to companies producing and using ENM. The companies were asked about their estimate of the worldwide or regional market and not about their company-specific production, information that they would be less likely to communicate. The study focused on the actual production quantities and not the production capacities. The survey also addressed information on distribution of the produced ENM to different product categories. The results reveal that some ENM are produced in Europe in small amounts (less than 10 t/ year for Ag, QDs and fullerenes). The most produced ENM is TiO 2 with up to 10,000 t of worldwide production. CeO 2 , FeO x , AlO x , ZnO, and CNT are produced between 100 and 1000 t/year. The data for SiO 2 cover the whole range from less than 10 to more than 10,000 t/year, which is indicative of problems related to the definition of this material (is pyrogenic silica considered an ENM or not?). For seven ENM we have obtained the first estimates for their distribution to different product categories, information that also forms the base for life-cycle based exposure analysis.

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There is scientific agreement that engineered nanomaterial (ENM) production, use and disposal lead to environmental release of ENM. However, very little is known on emissions of ENM to the environment. Currently, techniques are lacking to quantitatively monitor ENM emissions to and concentrations in the environment, and hence data on emissions and environmental concentrations are scarce. One of the few available studies reports the detection of nano-TiO(2) in water leaching from exterior facades. Some experimental evidence is available on the release of nanosized materials from commercial textiles during washing. A handful of modeling studies have investigated ENM release to the environment. These studies modeled either the release of ENMs to the environment from ENM containing products during the consumer usage, or the release throughout the whole life cycle of ENM and ENM-containing products. Sewage sludge, wastewater, and waste incineration of products containing ENM were shown to be the major flows through which ENMs end up in the environment. However, reliable data are particularly lacking on release during ENM production and on the application amounts and empirical information on release coefficients for all life cycle stages and environmental compartments. Quantitative data linking occupational exposure measurements and ENM emission flows into the environment are almost completely missing. Besides knowing the amounts of ENM released into the environment, it is equally important to investigate in what form ENMs are released. First results show that much of the ENM released from products is present in matrix-bound form, but that also some fraction is released as single, dispersed nanoparticles.

The widespread use of silver nanoparticles (Ag-NPs) in commercial products, especially textiles, will likely result in an unknown spread of Ag into the environment. The quantification and characterization of the Ag released from nano-Ag-products is an important parameter needed to predict the effect of Ag-NPs on the environment. The aim of this study was to determine the amount and the form of Ag released during washing from nine fabrics with different ways of silver incorporation into or onto the fibers. The effect of pH, surfactants, and oxidizing agents was evaluated. The results show that little dissolution of Ag-NPs occurs under conditions relevant to washing (pH 10) with dissolved concentrations 10 times lower than at pH 7. However, bleaching agents such as hydrogen peroxide or peracetic acid (formed by the perborate/TAED system) can greatly accelerate the dissolution of Ag. The amount and form of Ag released from the fabrics as ionic and particulate Ag depended on the type of Ag-incorporation into the textile. The percentage of the total silver emitted during one washing of the textiles varied considerably among products (from less than 1 to 45%). In the washing machine the majority of the Ag (at least 50% but mostly >75%) was released in the size fraction >450 nm, indicating the dominant role of mechanical stress. A conventional silver textile did not show any significant difference in the size distribution of the released silver compared to many of the textiles containing nano-Ag. These results have important implications for the risk assessment of Ag-textiles and also for environmental fate studies of nano-Ag, because they show that under conditions relevant to washing, primarily coarse Ag-containing particles are released.