Generation of two isogenic iPSC lines from a healthy male donor of European ancestry.

We have created two isogenic iPSC lines from fibroblasts of a healthy male donor of European ancestry. The cell lines express common pluripotency markers, are free of chromosomal aberrations and are able to differentiate into cells of all three germ layers. These iPSC are now a resource for genome editing with the aim of creating models of genetic disorders without having to depend on patient cells.

Generation of an iPSC line (UMGWi001-B) from a patient with Floating-Harbor Syndrome (FLHS) carrying a heterozygous SRCAP mutation (p.Arg2444).

Floating-Harbor syndrome (FLHS) is a rare genetic disease caused by mutations in the SRCAP gene. Here, we generated an induced pluripotent stem cell line from gingival fibroblasts of a male patient with a heterozygous mutation in exon 34 of the SRCAP gene (c.7330C > T, p.Arg2444*). The iPSC colonies have an atypical morphology with diffuse borders and disintegrate quickly upon touch. Still, the cell line expresses pluripotency markers and differentiates into three germ layers. The cell line can be used as patient-specific disease model and help elucidate the molecular mechanisms involving SRCAP in the context of FLHS.

Migration of Ag- and TiO2-(Nano)particles from textiles into artificial sweat under physical stress: experiments and exposure modeling.

Engineered nanoparticles (ENP) are increasingly used to functionalize textiles taking advantage, e.g., of the antimicrobial activity of silver (Ag)-ENP or the UV-absorption of titania (TiO2)-ENP. Mobilization and migration of ENPs from the textile into human sweat can result in dermal exposure to these nanoobjects and their aggregates and agglomerates (NOAA). In this study we assessed exposure to NOAA migrating from commercially available textiles to artificial sweat by an experimental setup that simulates wear-and-tear during physical activity. By combining physical stress with incubation in alkaline and acidic artificial sweat solutions we experimentally realized a worst case scenario for wearing functionalized textiles during sports activities. This experimental approach is not limited to NOAA, but can be used for any other textile additive. Out of four investigated textiles, one T-shirt and one pair of trousers with claimed antimicrobial properties were found to release Ag <450 nm in detectable amounts (23-74 µg/g/L). Textiles containing TiO2 for UV protection did not release significant amounts of TiO2 <450 nm, but the antimicrobial T-shirt released both TiO2 and Ag <450 nm. The silver was present in dissolved and particulate form, whereas TiO2 was mainly found as particulate. On the basis of our experimental results we calculated external dermal exposure to Ag and TiO2 for male and female adults per use. For silver, maximal amounts of 17.1 and 8.2 µg/kg body weight were calculated for total and particulate Ag <450 nm, respectively. For TiO2, the exposure levels amount to maximal 11.6 µg/kg body weight for total (mainly particulate) TiO2. In comparison with other human exposure pathways, dermal exposure to NOAA from textiles can be considered comparably minor for TiO2-NOAA, but not for Ag-NOAA.

Release of titanium dioxide from textiles during washing.

Nano-TiO(2) has the highest production of all nanomaterials, and pigment-TiO(2) is a commodity used on the million tons/year scale. Information on the release of TiO(2) from consumer products is therefore an important part of analyzing the potential environmental exposure to TiO(2). For this study, we investigated the release of TiO(2) from six different functional textiles during washing. TiO(2) is used in textiles because of its UV-absorbing properties and as pigment. Analysis of fiber cross sections showed that the TiO(2) was contained in the fiber matrix. The sun-protection textiles had Ultraviolet Protection Factors that were between 58 and 6100 after washing and therefore above the labeled factor of 50+. Five of the textiles (sun-protection clothes) released low amounts of Ti (0.01 to 0.06 wt % of total Ti) in one wash cycle. One textile (with antimicrobial functionality) released much higher amounts of Ti (5 mg/L, corresponding to 3.4 wt % of total Ti in one wash cycle). Size fractionation showed that about equal amounts were released as particles below and above 0.45 µm. After 10 washings, only in two textiles significantly lower Ti contents were measured. Electron microscopy showed that the TiO(2) particles released into washing solution had a roundish appearance with primary particle sizes between 60 and 350 nm that formed small aggregates with up to 20 particles. The results indicate that functional textiles release some TiO(2) particles, but that the amounts are relatively low and mostly not in the nanoparticulate range.

Characterization of silver release from commercially available functional (nano)textiles.

Silver, both in the nano as well as in other forms, is used in many applications including antimicrobial textiles. Washing of such textiles has already been identified as an important process that results in the release of silver into wastewater. This study thus investigated the release of silver from eight different commercially available silver-textiles during a washing and rinsing cycle. The silver released was size-fractionated and characterized using electron microscopy. In addition, the antimicrobial functionality of the textiles was tested before and after washing. Three of the textiles contained nanosized silver (labeled or confirmed by manufacturers' information), another used a metallic silver wire and four contained silver in undeclared form. The initial silver content of the textiles was between 1.5 and 2925mg Ag/kg. Only four of the investigated textiles leached detectable amounts of silver, of which 34-80% was in the form of particles larger than 450nm. Microscopic analysis of the particles released in the washing solutions identified Ti/Si-AgCl nanocomposites, AgCl nanoparticles, large AgCl particles, nanosilver sulfide and metallic nano-Ag, respectively. The nanoparticles were mainly found in highly agglomerated form. The identified nanotextiles showed the highest antimicrobial activity, whereas some of the other textiles, e.g. the one with a silver wire and the one with the lowest silver content, did not reduce the growth of bacteria at all. The results show that different silver textiles release different forms of silver during washing and that among the textiles investigated AgCl was the most frequently observed chemical form in the washwater.

Engineered nanomaterials in rivers--exposure scenarios for Switzerland at high spatial and temporal resolution.

Probabilistic material flow analysis and graph theory were combined to calculate predicted environmental concentrations (PECs) of engineered nanomaterials (ENMs) in Swiss rivers: 543 river sections were used to assess the geographical variability of nano-TiO(2), nano-ZnO and nano-Ag, and flow measurements over a 20-year period at 21 locations served to evaluate temporal variation. A conservative scenario assuming no ENM removal and an optimistic scenario covering complete ENM transformation/deposition were considered. ENM concentrations varied by a factor 5 due to uncertain ENM emissions (15%-85% quantiles of ENM emissions) and up to a factor of 10 due to temporal river flow variations (15%-85% quantiles of flow). The results indicate highly variable local PECs and a location- and time-dependent risk evaluation. Nano-TiO(2) median PECs ranged from 11 to 1'623 ng L(-1) (conservative scenario) and from 2 to 1'618 ng L(-1) (optimistic scenario). The equivalent values for nano-ZnO and nano-Ag were by factors of 14 and 240 smaller.

The behavior of silver nanotextiles during washing.

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.

Comparison of manufactured and black carbon nanoparticle concentrations in aquatic sediments.

In this paper, we show that concentrations of manufactured carbon-based nanoparticles (MCNPs) in aquatic sediments will be negligible compared to levels of black carbon nanoparticles (BCNPs). This is concluded from model calculations accounting for MCNP sedimentation fluxes, removal rates due to aggregation or degradation, and MCNP burial in deeper sediment layers. The resultant steady state MCNP levels are compared with BCNP levels calculated from soot levels in sediments and weight fractions of nanosized fractions of these soot particles. MCNP/BCNP ratios range from 10(-7) to 10(-4) (w:w). This suggests that the often acclaimed effect of MCNPs on organic pollutant binding and bioavailability will likely be below the level of detection if natural BCNPs are present, even if binding to MCNP is one to two orders of magnitude stronger than to BCNPs. Furthermore, exposure and toxic effects of MCNPs in sediments and soils will be negligible compared to that of BCNPs.

Metal solubility and speciation in the rhizosphere of Lupinus albus cluster roots.

The objective of this study was to investigate the influence of root exudation of organic acid anions on the speciation of major and trace metal cations in the rhizosphere of Lupinus albus cluster roots. Plants were grown in rhizoboxes containing repacked weakly acidic loam. Bulk soil solutions and, during the lifetime of cluster roots, rhizosphere solutions were collected using micro suction cups. During organic acid anion exudation bursts, metals in the rhizosphere of cluster roots were strongly mobilized. The concentrations of dissolved organic carbon derived from soil organic matter increased parallel to organic acid anions. Speciation calculations revealed that, during exudation, Al, Ca, Mn, and Zn in the cluster root rhizosphere were mainly bound with citrate, while Cu and Pb were always strongly bound to soil-derived dissolved organic matter. Our results indicate that cluster root exudation led on one hand to direct mobilization and complexation of metals like Al, Fe, and Zn by citrate and on the other hand to the mobilization of soil organic matter which complexes and solubilizes Cu and Pb.

Uptake of Zn and Fe by wheat (Triticum aestivum var. Greina) and transfer to the grains in the presence of chelating agents (ethylenediaminedisuccinic acid and ethylenediaminetetraacetic acid).

A way to decrease iron and zinc deficiency in humans is to biofortify foods by increasing the bioavailable contents in these elements. The aim of this work was to study if chelating agents could be used to increase the capture of Fe and Zn by wheat grains. Zn and/or Fe in combination with the chelating agents ethylenediaminedisuccinic acid (EDDS) or ethylenediaminetetraacetic acid (EDTA) were added at various times (i.e., at flower head formation, anthesis, and postanthesis) to spring wheat ( Triticum aestivum var. Greina) grown in nutrient solution. Treatments lasted for 2 weeks, and the plants were harvested at grain maturity. The shoots of treated plants accumulated higher Zn and/or Fe concentrations than untreated plants, depending on the treatment. The plants also accumulated significant concentrations of EDDS or EDTA in their shoots. Elevated Zn and Fe concentrations in the shoots did in most cases not lead to significantly higher Zn and Fe concentrations in the grains. The grains of plants treated with EDDS during flower head formation accumulated elevated Fe and Zn concentrations but at the cost of a reduction in yield. The control plants transferred higher percentages of Fe and Zn from the shoot into the grain than the treated plants. This indicates that EDTA and EDDS inhibited in most cases the translocation of Fe and Zn from the shoots into the grains. The amounts of EDDS and EDTA found in the grains of treated plants were very small. This indicates that there was little transfer of the chelates into the symplast and that the apoplastic pathway, which is important for the transport of chelants into the shoots, is efficiently blocked between shoots and seeds.

Determination of [S,S']-ethylenediaminedisuccinic acid by high-performance liquid chromatography.

A new high-performance liquid chromatography (HPLC) method for the determination of ethylenediaminedisuccinic acid (EDDS) is presented. Free EDDS(4-) and EDDS complexes with divalent metals undergo conversion to the Fe(III) complex in the presence of Fe(III)Cl(3). Fe(III)EDDS is separated by HPLC on an ion exchange column using (NH(4))(2)SO(4) eluent with detection at 258 nm. The detection limit is 0.01 microM. The method is applied to natural waters and soil solution samples. A background of natural water results in a reduction in EDDS peak area. The method is suited for EDDS analysis in samples with well-defined, simple matrices such as those used in laboratory experiments or biodegradation studies.

Sorption of trace metals by standard and micro suction cups in the absence and presence of dissolved organic carbon.

Both the bioavailability of a trace metal (TM) in a soil and the risk of leaching to the ground water are linked to the metals concentration in the soil solution. Sampling soil solution by tension lysimetry with suction cups is a simple and established technique that is increasingly used for monitoring dissolved TM in soils. Of major concern, however, is the sorption of TM by the walls of the samplers. Metal sorption by different materials used in suction cups can vary widely, depending also on the chemistry of the soil solution. We compared the sorption of Cu, Zn, Cd, and Pb by different standard-size and micro suction cups in the laboratory at two pH values (4.5 and 7.5 or 8.0) in absence and presence of dissolved organic carbon (DOC). In addition, we investigated the sorption of DOC from different origins by the cup materials. At both pH values, the weakest sorption of all four TMs was exhibited by standard-size suction cups based on nylon membranes and by hollow fibers made from polyvinyl alcohol (PVA). At alkaline pH, borosilicate glass, ceramic materials, and polytetrafluorethylene (PTFE) mixed with silicate were characterized by generally strong sorption of all investigated TMs. In addition, Cu and Pb were strongly sorbed at low pH by PTFE-silicate and a ceramic material used for the construction of standard-size suction cups. On the other hand, sorption of Cu, Zn, and Cd by ceramic capillaries produced from pure aluminum oxide was negligible at low pH. Micro suction cups made of an unknown polymerous tube sorbed Cu strongly, but were well suited to monitor Zn, Cd, and Pb at low pH, and, in the presence of DOC, also at high pH. Major cations (Na+, Mg2+, K+, Ca2+) and anions (Cl-, NO3-, SO4(2-)) were not or very weakly sorbed by all cup materials, except for Mg2+, K+, and Ca2+ by borosilicate glass at pH 7.5. Trace metal sorption by suction cups was generally greatly reduced in the presence of DOC, especially at alkaline pH. The sorption of DOC itself depended on its source. Dissolved organic carbon from leaf litter extracts with a probably large hydrophobic fraction was sorbed more strongly than mainly hydrophilic DOC from a mineral soil solution.

Elevated lead and zinc contents in remote alpine soils of the Swiss National Park.

Weathering of bedrock and pedogenic processes can result in elevated heavy metal concentrations in the soil. Small-scale variations in bedrock composition can therefore cause local variations in the metal content of the soil. Such a case was found in the remote alpine area of the Swiss National Park. Soil profiles were sampled at an altitude of about 2,400 m, representing soils developed above different bedrocks. The concentration of lead in the profiles was found to be strongly dependent on the metal content in the bedrock underlying the soil and was strongly enriched in the top 10 cm. The dolomitic bedrock in the study area contains elevated lead concentrations compared with other dolomites. Dissolution of dolomite and accumulation of weathering residues during soil formation resulted in high lead concentrations throughout the soil profile. The enrichment of lead in the topsoil, however, is largely attributed to atmospheric input. The isotopic signature of the lead clearly indicates that it is mainly of natural origin and that atmospheric deposition of anthropogenic lead contributed to about 20 to 40% to the lead concentration in the topsoil on the bedrock with elevated lead concentrations. In the soils on bedrock with normal lead concentrations, the anthropogenic contribution is estimated to be about 75%. Also, zinc was very strongly enriched in the topsoil. This enrichment was closely correlated with the organic matter distribution in the profiles, suggesting that recycling through plant uptake and litter deposition was a dominant process in the long-term retention of this metal in the soil.

Determination of chlorate at low microgram/l levels by ion-chromatography with postcolumn reaction.

A new method for the determination of low concentrations of chlorate in natural waters is described. Chlorate is analyzed by ion-chromatography followed by an osmate-catalyzed postcolumn reaction of chlorate with iodide and UV-detection of triiodide. The new osmate catalysis allows to carry out the oxidation of iodide by chlorate at pH 3 instead of 6 M HCl for the uncatalyzed reaction. A detection limit of 5 nM (0.4 microgram/l) chlorate is achieved. The method also allows the simultaneous determination of chlorite, bromate, and nitrite at the low microgram/l level.

Adsorption of Phosphonates onto the Goethite-Water Interface.

The adsorption of one phosphonate, two hydroxyphosphonates, and five aminophosphonates onto the iron (hydr)oxide goethite (alpha-FeOOH) has been studied as a function of pH. At phosphonate concentrations significantly lower than the total number of available surface sites, nearly 100% adsorption is observed below pH 8.0. Adsorption decreases to negligible levels as the pH is increased to 12.0. Under the conditions just described, adsorption of nitrilotris(methylenephosphonic acid) as a function of pH is nearly independent of the ionic strength (from 1 mM to 1 M). At phosphonate concentrations close to the total number of available surface sites, adsorption decreases over a broader range in pH and reflects the number of phosphonate groups. At pH 7.2, the maximum extent of adsorption decreases as the number of phosphonate groups increases from one to five. Adsorption is modeled using a 2-pK constant capacitance model that postulates formation of a 1:1 surface complex involving one surface site and one phosphonate functional group. Denoting the fully deprotonated phosphonate ligand as La-, different protonation levels for adsorbed phosphonate species are represented by a series of equilibrium constants of the form For a phosphonate of charge a-, there are (a - 1) possible surface protonation levels. For a surface protonation level n, log betan,surf values derived from this modeling approach are related to the surface complex charge Z through the following linear relationship: Using this approach, adsorption as a function of phosphonate concentration and pH can be fully accounted for. Copyright 1999 Academic Press.

Determination of phosphonates in natural waters by ion-pair high-performance liquid chromatography.

The paper describes a new method for the determination of phosphonates by ion-pair high-performance liquid chromatography. The phosphonates are complexed with Fe(III) and separated on a reversed-phase polymer column. The eluent consists of a bicarbonate solution at pH 8.3, tetrabutylammoniumbromide as counter-ion and 14% acetonitrile. The complexes are detected at 260 nm. The four phosphonates HEDP (1-hydroxyethylene-1,1-diphosphonic acid). ATMP (aminotris [methylenephosphonic acid]), EDTMP [ethylenediaminetetra(methylenephosphonic acid)], and DTPMP [diethylenetriaminepenta (methylenephosphonic acid)] are well separated within 20 min. The limits of detection are 5.10(-8) M for ATMP and EDTMP, 1.10(-7) M for DTPMP and 5.10(-7) M for HEDP. The method is suitable for the determination of phosphonates in the influent and effluent of wastewater treatment plants. A preconcentration of 10 is easily achieved by adsorption of the phosphonates onto freshly precipitated calcium carbonate and subsequent dissolution of the solid-phase by HCl.

Adsorption of EDTA and Metal-EDTA Complexes onto Goethite.

The adsorption characteristics of a variety of divalent and trivalent metal-EDTA complexes onto goethite (alpha-FeOOH) were examined in aqueous solution. Uncomplexed EDTA is adsorbed as a binuclear complex at low pH and as a mononuclear complex at high pH. Adsorption is ligand-like with a high extent of adsorption at low pH. The process can be described by formation of inner-sphere complexes by the surface complexation model with constant capacitance. The EDTA complexes of the divalent metals Ca, Zn, Ni, Cu, Co(II), and Pb, which are quinquedentate in solution (free donor atoms bound to the metal ion), all showed the same ligand-like adsorption behavior. Their adsorption as a function of pH and concentration can be described by the formation of one type of ternary surface complex and can be fitted with the same equilibrium constant. Pd(II)EDTA, which is bidentate or quadridentate in solution, is adsorbed more strongly, but also in a ligand-like manner. The EDTA complexes of the trivalent metals LaEDTA and BiEDTA are adsorbed very strongly over the whole pH range. The sexidentate complex of Co(III) is weakly adsorbed at low pH outer-spherically, i.e., by electrostatic interaction only. Fe(III)EDTA is weakly adsorbed over the whole pH range with a predominant nonspecific surface complex at low pH and a specific complex at high pH.

Determination of dissolved and adsorbed EDTA species in water and sediments by HPLC.

This paper describes a method for determining EDTA species in various environmental samples at low molar concentrations by high-performance liquid chromatography (HPLC). Distinction between Fe(III)EDTA and all the other species can be made. NiEDTA can be detected semiquantitatively. The fraction of EDTA adsorbed to suspended particles or to sediments can be determined after desorption with phosphate. After complexation with Fe(III), the EDTA is detected by reversed-phase ion-pair liquid chromatography as the Fe(III)EDTA complex at a wavelength of 258 nm. The behavior of a variety of metal-EDTA complexes during analysis was checked. Determination of different EDTA species (Fe(III)EDTA, NiEDTA, and adsorbed EDTA) is possible in river water, groundwater, and effluents from wastewater treatment plants. Fe(III)EDTA was found to be the main species, at 30-70%; NiEDTA was <10% in most of the samples. Adsorbed EDTA was detected in suspended particles from rivers and wastewater treatment plants and in sediment cores from a lake. The method is suitable for a variety of different samples with different concentration ranges.