Approach toward In Vitro-Based Human Toxicity Effect Factors for the Life Cycle Impact Assessment of Inhaled Low-Solubility Particles.

Today's scarcity of animal toxicological data for nanomaterials could be lifted by substituting in vivo data with in vitro data to calculate nanomaterials' effect factors (EF) for Life Cycle Assessment (LCA). Here, we present a step-by-step procedure to calculate in vitro-to-in vivo extrapolation factors to estimate human Benchmark Doses and subsequently in vitro-based EFs for several inhaled nonsoluble nanomaterials. Based on mouse data, the in vitro-based EF of TiO2 is between 2.76 · 10-4 and 1.10 · 10-3 cases/(m2/g·kg intake), depending on the aerodynamic size of the particle, which is in good agreement with in vivo-based EFs (1.51 · 10-4-5.6 · 10-2 cases/(m2/g·kg intake)). The EF for amorphous silica is in a similar range as for TiO2, but the result is less robust due to only few in vivo data available. The results based on rat data are very different, confirming the importance of selecting animal species representative of human responses. The discrepancy between in vivo and in vitro animal data in terms of availability and quality limits the coverage of further nanomaterials. Systematic testing on human and animal cells is needed to reduce the variability in toxicological response determined by the differences in experimental conditions, thus helping improve the predictivity of in vitro-to-in vivo extrapolation factors.

Prospective Dynamic and Probabilistic Material Flow Analysis of Graphene-Based Materials in Europe from 2004 to 2030.

As industrial demand for graphene-based materials (GBMs) grows, more attention falls on potential environmental risks. The present article describes a first assessment of the environmental releases of GBMs using dynamic probabilistic material flow analysis. The model considered all current or expected uses of GBMs from 2004 to 2030, during which time there have already been significant changes in how the graphene mass produced is distributed to different product categories. Although the volume of GBM production is expected to grow exponentially in the coming years, outflow from the consumption of products containing GBMs shows only a slightly positive trend due to their long lifetimes and the large in-use stock of some applications (e.g., GBM composites used in wind turbine blades). From consumption and end-of-life phase GBM mass flows in 2030, estimates suggest that more than 50% will be incinerated and oxidized in waste plants, 16% will be landfilled, 12% will be exported out of Europe, and 1.4% of the annual production will flow to the environment. Predicted release concentrations for 2030 are 1.4 ng/L in surface water and 20 µg/kg in sludge-treated soil. This study's results could be used for prospective environmental risk assessments and as input for environmental fate models.

Size-Specific, Dynamic, Probabilistic Material Flow Analysis of Titanium Dioxide Releases into the Environment.

Most of the existing exposure models for engineered nanomaterials (ENMs) do not consider particle size, crystalline forms, and coating materials that all may influence the material's fate, transport, and toxicity. Our work aimed to incorporate particle size distributions into a material flow analysis (MFA) to develop a size-specific, dynamic, probabilistic MFA model (ss-DPMFA). Using titanium dioxide (TiO2) as a first case study, we aimed to determine the contribution of conventional TiO2 pigments to the total amount of nanoscale TiO2 released into the environment. Besides providing information on mass flows, the new model used particle size distributions and crystalline forms to describe the stocks and flows of TiO2. The most striking modeling result to emerge was that before TiO2 ENMs came onto the market as such in 2000, 22,400 tons of nanosized (<100 nm) TiO2 particles had already been released into the environment, originating from conventional TiO2 pigments. Even in 2016, 50% of the nanosized TiO2 particles released into wastewater came from the nanosized fraction of TiO2 particles in pigments. Quantitative data on the particle size distribution of TiO2 particles released into the environment can be used as input for environmental fate models. Our new ss-DPMFA model's additional insights about crystalline forms and coatings could pave the way for advanced size- and form-specific hazard and risk assessments for other nanomaterials in ecological systems.

Characterization of Nanoplastics, Fibrils, and Microplastics Released during Washing and Abrasion of Polyester Textiles.

Nanoplastics (defined here as plastic particles smaller than 1000 nm) released during the daily use of plastic products are gaining increasing attention due to their potential effects on human and environmental health. Formation of nanoplastics has been reported so far for diverse plastic products under varying conditions of use. The washing of synthetic textiles has been identified as an important source of microplastic fibers (MPF) released to the environment. In addition, abrasion of textiles was shown to induce further fragmentation of fibers and subsequent formation of much smaller and shorter fibrils. The aim of this work was to identify whether washing and wearing of textiles also results in the formation of nanoplastics. We designed washing and abrasion experiments to investigate the morphology, number, and size of micro- and nanoplastics released from polyester textiles. Using a combination of techniques including scanning transmission X-ray microspectroscopy (STXM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA), we were able to quantify nanoplastics (average hydrodynamic diameter 173-188 nm), microplastic fibrils (diameter 3 ± 1 µm, length 20-160 µm), and MPFs (diameter 16 ± 7 µm, length up to 5 mm). The presence of polyester nanoplastics was confirmed by the near edge X-ray absorption fine spectra (NEXAFS) of the nanoparticles in the abrasion and washing samples for particles larger than 100 nm. We estimated that in the abraded samples, 1 g of fleece textile released an average of 2.1× 1011 nanoplastic particles (1.4 mg), 1.4 × 104 MPFs (1.0 mg), and 5.3 × 105 fibrils (0.5 mg) based on SEM images and NTA. In the nonabraded samples, 1 g of textile released an average of 3.3 × 1011 nanoplastic particles (2.1 mg), 2.8 × 103 MPFs (0.2 mg), and no fibrils. The present study is the first to show a significant release of polyester nanoplastics during the washing and abrasion of synthetic textiles.

Formation of Fiber Fragments during Abrasion of Polyester Textiles.

Fiber fragments are one of the dominant types of microplastics in environmental samples, suggesting that synthetic textiles are a potential source of microplastics to the environment. Whereas the release of microplastics during washing of textiles is already well studied, much less is known about the release during abrasion processes. The abrasion of textiles may induce fibrillation of fibers and therefore result in the formation of much finer fiber fragments. The aim of this study was to investigate the influence of abrasion of synthetic textiles on the formation of microplastic fibers and fibrils. Fleece and interlock textile swatches made of polyester were abraded using abrasion tests with a Martindale tester. The microplastic fibers and fibrils formed during abrasion were extracted from the textiles and characterized in terms of number, length, and diameter. The microplastic fibers demonstrated the same diameter than the fibers found in the textiles (fleece: 12.3 µm; interlock: 12.7 µm), while fibrils with a much smaller diameter (fleece: 2.4 µm; interlock: 4.9 µm) were also found. The number of fibrils formed during abrasion in both textiles was higher than the number of microplastic fibers. The majority of the extracted microplastic fibers had a length between 200 and 800 µm, while most fibrils were between 30 and 150 µm, forming two distinct fiber fragment morphologies. The number of microplastic fibers formed during abrasion was 5 to 30 times higher than the number of microplastic fibers that could be extracted from non-abraded samples. The number of fibrils increased after abrasion by more than a factor of 200 for both fabric types. The fibrils formed during abrasion have diameters that fall within the inhalable size for airborne particles. The potential release of fibrils into air during wear of textiles thus raises questions about the human exposure to these materials. Since the Martindale tester can simulate a daily application scenario of textiles over a prolonged period only in a limited way, future studies are needed to establish the correlation between the test results with a real-world scenario.

Systematic Study of Microplastic Fiber Release from 12 Different Polyester Textiles during Washing.

Microplastic fibers (MPFs) have been found to be a major form of microplastics in freshwaters, and washing of synthetic textiles has been identified as one of their main sources. The aim of this work was to use a panel of 12 different textiles of representative fibers and textile types to investigate the source(s) of the MPF during washing. Using standardized washing tests, textile swatches tailored using five different cutting/sewing methods were washed up to 10 times. The MPF quantity and fiber length were determined using image analysis. The 12 textiles demonstrated great variability in MPF release, ranging from 210 to 72,000 MPF/g textile per wash. The median MPF length ranged from 165 to 841 µm. The number of released MPF was influenced by the cutting method, where scissor-cut samples released 3-21 times higher numbers of MPF than the laser-cut samples. The textiles with mechanically processed surfaces (i.e., fleece) released significantly more (p-value < 0.001) than the textiles with unprocessed surfaces. For all textiles, the MPF release decreased with repeated wash cycles, and a small continuous fiber release was observed after 5-6 washings, accompanied by a slight increase in the fiber length. The decrease in the number of MPF released is likely caused by depletion of the production-inherited MPFs trapped within the threads or the textile structure. The comparison of MPF release from laser-cut samples, which had sealed edges, and the other cutting methods allowed us to separate the contributions of the edge- and surface-sourced fibers from the textiles to the total release. On an average, 84% (range 49-95%) of the MPF release originated from the edges, highlighting the importance of the edge-to-surface ratio when comparing different release studies. The large contribution of the edges to the total release offers options for technical solutions which have the possibility to control MPF formation throughout the textile manufacturing chain by using cutting methods which minimize MPF formation.

Polymer-Specific Modeling of the Environmental Emissions of Seven Commodity Plastics As Macro- and Microplastics.

Plastic has been identified as an emerging contaminant in aquatic and terrestrial ecosystems. Uncertainties remain concerning the amounts present in the environment and the main responsible sources. In this study, the emissions of macro- and microplastics have been mapped for seven polymers in Switzerland. The modeling is based on a complete analysis of the flows from production and use to end-of-life using probabilistic material flow analysis. We estimate that 94 ± 34 g/capita/year of low-density polyethylene, 98 ± 50 g/cap/a of high-density polyethylene, 126 ± 43 g/cap/a of polypropylene, 24 ± 13 g/cap/a of polystyrene, 16 ± 12 g/cap/a of expanded polystyrene, 65 ± 36 g/cap/a of polyvinyl chloride, and 200 ± 120 g/cap/a of polyethylene terephthalate enter the Swiss environment. All polymers combined, 540 ± 140 and 73 ± 14 g/cap/a are emitted into soil as macroplastics and microplastics, respectively, and 13.3 ± 4.9 and 1.8 ± 1.1 g/cap/a are emitted into freshwater as macroplastics and microplastics, respectively. The leading emission pathway is littering for both terrestrial and aquatic environments. Construction, agriculture, and pre- and postconsumer processes cause important emissions of microplastics into soils, and postconsumer processes, textiles, and personal care products release most of the microplastics into waters. Because mass flows into soils are predicted to be 40 times larger than those into waters, more attention should be placed on this compartment. Our work also highlights the importance of referring to specific polymers instead of just "plastics".

Environmental hazard assessment for polymeric and inorganic nanobiomaterials used in drug delivery.

BACKGROUND: The increasing development and use of nanobiomaterials raises questions about their potential adverse effects on the environment after excretion and release. Published ecotoxicological data was searched for five polymeric nanobiomaterials [chitosan, polylactic acid (PLA), polyacrylonitrile (PAN), polyhydroxyalkanoates (PHA), and poly(lactic-glycolic acid) (PLGA)] and one inorganic nanobiomaterial [hydroxyapatite (HAP)] to evaluate the environmental hazards for freshwater and soil using a meta-analysis. If enough data was available, a probabilistic species sensitivity distribution (pSSD) and from this a predicted no effect concentration (PNEC) was calculated. If only one data point was available, a PNEC was calculated based on the most sensitive endpoint. Each material was classified either as "nano" or "non-nano", depending on the categorization in the original articles. When the original article specified that the material consisted of nanoparticles, the material was classified as nano; when nothing was mentioned, the material was classified as "non-nano". RESULTS: For PLA, PHA and PLGA, no published data on ecotoxicity was found and therefore no hazard assessment could be conducted. In soils, HAP was found to have the lowest PNEC with 0.3 mg/kg, followed by PAN and chitosan. In freshwater, chitosan was found to have the lowest PNEC with 5 µg/l, followed by nano-chitosan, HAP and PAN. CONCLUSION: Compared with other common pollutants, even the most sensitive of the selected nanobiomaterials, chitosan, is less toxic than engineered nanomaterials such as nano-ZnO and nano-Ag, some common antibiotics, heavy metals or organic pollutants such as triclosan. Given the current knowledge, the nanobiomaterials covered in this work therefore pose only little or no environmental hazard.

Probabilistic Material Flow Analysis of Seven Commodity Plastics in Europe.

The omnipresence of plastics in our lives and their ever-increasing application range continuously raise the requirements for the monitoring of environmental and health impacts related to both plastics and their additives. We present a static probabilistic material flow analysis of seven polymers through the European and Swiss anthropospheres to provide a strong basis for exposure assessments of polymer-related impacts, which necessitates that the plastic flows from production to use and finally to waste management are well-understood. We consider seven different polymers, chosen for their popularity and application variety: low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), expanded polystyrene (EPS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET). We include synthetic textile products and consider trade flows at various stages of the life cycle, thus achieving a complete overview of the consumption for these polymers. In Europe, the order of consumption is PP > LDPE > PET > HDPE > PVC > PS > EPS. Textile products account for 42 ± 3% of the consumption of PET and 22 ± 4% of PP. Incineration is the major waste management method for HDPE, PS, and EPS. No significant difference between landfilling and incineration for the remaining polymers is found. The highest recycling share is found for PVC. These results can serve as a basis for a detailed assessment of exposure pathways of plastics or their additives in the environment or exposure of additives on human health.

The need for a life-cycle based aging paradigm for nanomaterials: importance of real-world test systems to identify realistic particle transformations.

Assessing the risks of manufactured nanomaterials (MNM) has been almost exclusively focused on the pristine, as-produced materials with far fewer studies delving into more complex, real world scenarios. However, when considering a life-cycle perspective, it is clear that MNM released from commercial products during manufacturing, use and disposal are far more relevant both in terms of more realistic environmental fate and transport as well as environmental risk. The quantity in which the particles are released and their (altered) physical and chemical form should be identified and it is these metrics that should be used to assess the exposure and hazard the materials pose. The goal of this review is to (1) provide a rationale for using a life-cycle based approach when dealing with MNM transformations, (2) to elucidate the different chemical and physical forces which age and transform MNM and (3) assess the pros and cons of current analytical techniques as they pertain to the measurement of aged and transformed MNM in these complex release scenarios. Specifically, we will describe the possible transformations common MNM may undergo during the use or disposal of nano-products based on how these products will be used by the consumer by taking stock of the current nano-enabled products on the market. Understanding the impact of these transformations may help forecast the benefits and/or risks associated with the use of products containing MNM.

Polyester Textiles as a Source of Microplastics from Households: A Mechanistic Study to Understand Microfiber Release During Washing.

Microplastic fibers make up a large proportion of microplastics found in the environment, especially in urban areas. There is good reason to consider synthetic textiles a major source of microplastic fibers, and it will not diminish since the use of synthetic fabrics, especially polyester, continues to increase. In this study we provide quantitative data regarding the size and mass of microplastic fibers released from synthetic (polyester) textiles during simulated home washing under controlled laboratory conditions. Consideration of fabric structure and washing conditions (use of detergents, temperature, wash duration, and sequential washings) allowed us to study the propensity of fiber shedding in a mechanistic way. Thousands of individual fibers were measured (number, length) from each wash solution to provide a robust data set on which to draw conclusions. Among all the variables tested, the use of detergent appeared to affect the total mass of fibers released the most, yet the detergent composition (liquid or powder) or overdosing of detergent did not significantly influence microplastic release. Despite different release quantities due to the addition of a surfactant (approximately 0.025 and 0.1 mg fibers/g textile washed, without and with detergent, respectively), the overall microplastic fiber length profile remained similar regardless of wash condition or fabric structure, with the vast majority of fibers ranging between 100 and 800 µm in length irrespective of wash cycle number. This indicates that the fiber staple length and/or debris encapsulated inside the fabric from the yarn spinning could be directly responsible for releasing stray fibers. This study serves as a first look toward understanding the physical properties of the textile itself to better understand the mechanisms of fiber shedding in the context of microplastic fiber release into laundry wash water.

Improvements in Nanoparticle Tracking Analysis To Measure Particle Aggregation and Mass Distribution: A Case Study on Engineered Nanomaterial Stability in Incineration Landfill Leachates.

Numerous nanometrology techniques have been developed in recent years to determine the size, concentration, and a number of other characteristics of engineered nanomaterials (ENM) in environmental matrices. Among the many available techniques, nanoparticle tracking analysis (NTA) can measure individual particles to create a size distribution and measure the particle number. Therefore, we explore the possibility to use these data to calculate the particle mass distribution. Additionally, we further developed the NTA methodology to explore its suitability for analysis of ENM in complex matrices by measuring ENM agglomeration and sedimentation in municipal solid waste incineration landfill leachates over time. 100 nm Au ENM were spiked into DI H2O and synthetic and natural leachates. We present the possibility of measuring ENM in the presence of natural particles based on differences in particle refractivity indices, delineate the necessity of creating a calibration curve to adjust the given NTA particle number concentration, and determine the instruments linear range under different conditions. By measuring the particle size and the particle number distribution, we were able to calculate the ENM mass remaining in suspension. By combining these metrics together with transmission electron microscopy (TEM) analyses, we could assess the extent of both homo- and heteroagglomeration as well as particle sedimentation. Reporting both size and mass based metrics is common in atmospheric particle measurements, but now, the NTA can give us the possibility of applying the same approach also to aqueous samples.

Envisioning Nano Release Dynamics in a Changing World: Using Dynamic Probabilistic Modeling to Assess Future Environmental Emissions of Engineered Nanomaterials.

The need for an environmental risk assessment for engineered nanomaterials (ENM) necessitates the knowledge about their environmental emissions. Material flow models (MFA) have been used to provide predicted environmental emissions but most current nano-MFA models consider neither the rapid development of ENM production nor the fact that a large proportion of ENM are entering an in-use stock and are released from products over time (i.e., have a lag phase). Here we use dynamic probabilistic material flow modeling to predict scenarios of the future flows of four ENM (nano-TiO2, nano-ZnO, nano-Ag and CNT) to environmental compartments and to quantify their amounts in (temporary) sinks such as the in-use stock and ("final") environmental sinks such as soil and sediment. In these scenarios, we estimate likely future amounts if the use and distribution of ENM in products continues along current trends (i.e., a business-as-usual approach) and predict the effect of hypothetical trends in the market development of nanomaterials, such as the emergence of a new widely used product or the ban on certain substances, on the flows of nanomaterials to the environment in years to come. We show that depending on the scenario and the product type affected, significant changes of the flows occur over time, driven by the growth of stocks and delayed release dynamics.

Cytotoxic effects of nanosilver are highly dependent on the chloride concentration and the presence of organic compounds in the cell culture media.

BACKGROUND: Nanosilver shows great promise for use in industrial, consumer or medical products because of its antimicrobial properties. However, the underlying mechanisms of the effects of silver nanoparticles on human cells are still controversial. Therefore, in the present study the influence of the chloride concentration and different serum content of culture media on the cytotoxic effects of nanosilver was systematically evaluated. RESULTS: Our results show that nanosilver toxicity was strongly affected by the composition of the culture media. The chloride concentration, as well as the carbon content affected the silver agglomeration and the complex formation. But also the dissolution of nanosilver and the availability of free silver ions (Ag+) were severely affected by the compositions of the culture media. Cells, only exposed to silver particles in suspension and dissolved silver complexes, did not show any effects under all conditions. Nanosilver agglomerates and silver complexes were not very soluble. Thus, cells growing on the bottom of the culture dishes were exposed to sedimented nanosilver agglomerates and precipitated silver complexes. Locally, the concentration of silver on the cell surface was very high, much higher compared the silver concentration in the bulk solution. The cytotoxic effects of nanosilver are therefore a combination of precipitated silver complexes and organic silver compounds rather than free silver ions. CONCLUSIONS: Silver coatings are used in health care products due to their bacteriostatic or antibacterial properties. The assessment of the toxicity of a certain compound is mostly done using in vitro assays. Therefore, cytotoxicity studies of nanosilver using human cell cultures have to be undertaken under well controlled and understood cultivations conditions in order to improve the compatibility of different studies. Especially when eukaryotic versus prokaryotic systems are compared for the evaluation of the use of nanosilver as antibacterial coatings for implants in order to prevent bacterial colonization.

Dynamic Probabilistic Modeling of Environmental Emissions of Engineered Nanomaterials.

The need for an environmental risk assessment for engineered nanomaterials (ENM) necessitates the knowledge about their environmental concentrations. Despite significant advances in analytical methods, it is still not possible to measure the concentrations of ENM in natural systems. Material flow and environmental fate models have been used to provide predicted environmental concentrations. However, almost all current models are static and consider neither the rapid development of ENM production nor the fact that many ENM are entering an in-use stock and are released with a lag phase. Here we use dynamic probabilistic material flow modeling to predict the flows of four ENM (nano-TiO2, nano-ZnO, nano-Ag and CNT) to the environment and to quantify their amounts in (temporary) sinks such as the in-use stock and ("final") environmental sinks such as soil and sediment. Caused by the increase in production, the concentrations of all ENM in all compartments are increasing. Nano-TiO2 had far higher concentrations than the other three ENM. Sediment showed in our worst-case scenario concentrations ranging from 6.7 µg/kg (CNT) to about 40 000 µg/kg (nano-TiO2). In most cases the concentrations in waste incineration residues are at the "mg/kg" level. The flows to the environment that we provide will constitute the most accurate and reliable input of masses for environmental fate models which are using process-based descriptions of the fate and behavior of ENM in natural systems and rely on accurate mass input parameters.

Unraveling the Complexity in the Aging of Nanoenhanced Textiles: A Comprehensive Sequential Study on the Effects of Sunlight and Washing on Silver Nanoparticles.

The scientific understanding of nanoparticle (NP) release and transformations they undergo during the product life cycle is hampered by the narrow scope of many research endeavors in terms of both breadth of variables and completeness of analytical characterization. We conducted a comprehensive suite of studies to reveal overarching mechanisms and parameters for nanosilver transformations either still adhered to the fabric or when released after washing. Laboratory prepared nanoenhanced fabrics were investigated: three Ag variants and one Au used as an unreactive reference to separate mechanical from chemical releases. Sequential combinations of sunlight irradiation and/or washing in seven different detergent formulations was followed by NP characterization divided into two groups: (1) dissolved and particulate matter in the wash solutions and (2) the fraction that remained on the fabric. Analytical techniques included spICP-MS, XANES, TEM, SEM, and total metals analysis of fabric digests and wash water filtrates. Sunlight irradiation stabilizes metallic Ag upon washing. Detergents containing oxidizing agents assisted with Ag particle release but not Au NPs, inferring additional chemical mechanisms. While particle size played some role, the NP capping agent/fabric binder combination was a key factor in release. When particles were released, little alteration in size was observed. The use of well-controlled fabrics, unreactive reference materials, and a life-cycle based experimental regime are paramount to understanding changes in Ag speciation and release upon use of nanoenhanced textiles.

Textile Functionalization and Its Effects on the Release of Silver Nanoparticles into Artificial Sweat.

This study addresses the release of total silver (Ag) and silver nanoparticles (Ag-NPs) from textiles into artificial sweat, particularly considering the functionalization technology used in textile finishing. Migration experiments were conducted for four commercially available textiles and for six laboratory-prepared textiles. Two among these lab-prepared textiles represent materials in which Ag-NPs were embedded within the textile fibers (composites), whereas the other lab-prepared textiles contain Ag particles on the respective fiber surfaces (coatings). The results indicate a smaller release of total Ag from composites in comparison to surface-coated textiles. The particulate fraction determined within the artificial sweat was negligible for most textiles, meaning that the majority of the released Ag is present as dissolved Ag. It is also relevant to note that nanotextiles do not release more particulate Ag than conventional Ag textiles. The results rather indicate that the functionalization type is the most important parameter affecting the migration. Furthermore, after measuring different Ag-NP types in their pristine form with inductively coupled plasma mass spectrometry in the single particle mode, there is evidence that particle modifications, like surface coating, may also influence the dissolution behavior of the Ag-NPs in the sweat solutions. These factors are important when discussing the likelihood of consumer exposure.

Meeting the Needs for Released Nanomaterials Required for Further Testing-The SUN Approach.

The analysis of the potential risks of engineered nanomaterials (ENM) has so far been almost exclusively focused on the pristine, as-produced particles. However, when considering a life-cycle perspective, it is clear that ENM released from genuine products during manufacturing, use, and disposal is far more relevant. Research on the release of materials from nanoproducts is growing and the next necessary step is to investigate the behavior and effects of these released materials in the environment and on humans. Therefore, sufficient amounts of released materials need to be available for further testing. In addition, ENM-free reference materials are needed since many processes not only release ENM but also nanosized fragments from the ENM-containing matrix that may interfere with further tests. The SUN consortium (Project on "Sustainable Nanotechnologies", EU seventh Framework funding) uses methods to characterize and quantify nanomaterials released from composite samples that are exposed to environmental stressors. Here we describe an approach to provide materials in hundreds of gram quantities mimicking actual released materials from coatings and polymer nanocomposites by producing what is called "fragmented products" (FP). These FP can further be exposed to environmental conditions (e.g., humidity, light) to produce "weathered fragmented products" (WFP) or can be subjected to a further size fractionation to isolate "sieved fragmented products" (SFP) that are representative for inhalation studies. In this perspective we describe the approach, and the used methods to obtain released materials in amounts large enough to be suitable for further fate and (eco)toxicity testing. We present a case study (nanoparticulate organic pigment in polypropylene) to show exemplarily the procedures used to produce the FP. We present some characterization data of the FP and discuss critically the further potential and the usefulness of the approach we developed.

Effect of Variations of Washing Solution Chemistry on Nanomaterial Physicochemical Changes in the Laundry Cycle.

Engineered nanoparticle (ENP) life cycles are strongly dependent on the life-cycle of the nanoenhanced products in which they are incorporated. An important phase for ENP associated with textiles is washing. Using a set of liquid and powdered commercially available detergents that span a wide range of different chemistries, washing studies were performed with one "standard" nanoparticle suspended in wash solution to systematically investigate (changes to) particle size distribution, dissolution, reprecipitation (i.e., "new" particle formation), and complexation to particulate matter. Au ENPs were used as a "tracer" through the system. TEM and EDX analysis were performed to observe morphological and chemical changes to the particles, and single-particle ICP-MS was used to build a size distribution of particles in solution. Varying the washing solution chemistry was found to dictate the extent and rate of dissolution, particle destruction, surface chemistry change(s), and new particle formation. Detergent chemistry, dominated by oxidizing agents, was a major factor. The detergent form (i.e., powder vs liquid) was the other decisive factor, with powder forms providing available surfaces for precipitation and sorption reactions. Control experiments with AgNO3 indicated metallic Ag particles formed during the washing process from dissolved Ag, implying not all Ag-NPs observed in a textile washing study are indicative of released Ag-ENPs but can also be the result of sequential dissolution/reduction reactions.