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The electrochemical corrosion of ductile pipes (DPs) in drinking water distribution systems (DWDS) has a crucial impact on cement-mortar lining (CML) failure and metal release, potentially leading to drinking water quality deterioration and posing a risk to public health. An in-situ scanning vibrating electrode technique (SVET) with micron-scale resolution, microscopic scale detection and water quality analysis were used to investigate the corrosion behavior and metal release from DPs throughout the whole CML failure process. Metal pollutants release occurred at three different stages of CML failure process, and there are potential risks of water quality deterioration exceeding the maximum allowable levels set by national standards in the partial failure stage and lining peeling stage. Furthermore, the effects of water chemistry (Cl−, SO 4 2−, NO 3 −, and Ca2+) on corrosion scale growth and iron release activity, were investigated during the CML partial failure stage. Results showed that the CML failure process in DPs was accelerated by the autocatalysis of localized corrosion. Cl− was found to damage the uncorroded metal surface, while SO 4 2− mainly dissolved the corrosion scale surface, increasing iron release. Both the oxidation of NO 3 − and selective sedimentation of Ca2+ were found to enhance the stability of corrosion scales and inhibit iron release. [ABSTRACT FROM AUTHOR]

There have been several attempts in enhancing corrosion jar testing methods to better mimic realworld conditions found in drinking water distribution systems. A key feature that is generally omitted in such studies is zero headspace and the lack of interaction with the atmosphere within the jars as well as the flow interactions which affect total metal release. This work proposes a modified method to typical corrosion jar testing protocols to better simulate distribution system conditions. Modified separatory funnels with the addition of a rubber stopper and coupon holder were set-up to allow an in-flow and out-flow for water replacement every three to 4 d. The results demonstrated the effectiveness and reproducibility of the modified method, specifically with the analysis of variance conducted. A synthetic water test using both the modified and original methods showed a statistical difference between the two, and decreased variability in the metal release with the new procedure. Enhanced dissolved oxygen depletion was also observed with the modified method. The results of another study conducted, using actual waters, was used to create an empirical model with the water quality parameters measured, and the total metal release. This model was a good fit, with a 0.81 R-squared value and a 0.71 linear slope between the predicted and measured copper concentrations. In addition, first-order rate law models were created for fitting the metal release observed. The resultant equations were not good fits the batch testing conducted, however, the first-rate models created for the direct-connection study resulted in up to a 0.98 R-squared value with slopes close to unity when plotting the calculated vs. measured metal release. [ABSTRACT FROM AUTHOR]

• HTC treatment sanitizes sewage sludge and greatly facilitates P recovery. • HTC temperature and extraction time largely influenced efficiency of P extraction. • Oxalate ions achieved the highest rate of P release at pH > 0. • Ca, Zn, Cu and Pb release with oxalate ions was notably reduced at pH > 1. • Ca and Fe oxalate precipitate was confirmed by XRD. Hydrothermal carbonization (HTC) is a treatment technique with great potential for sanitizing digested sewage sludge (SS) and converting it into valuable products. In particular, phosphorus (P) recovery from hydrothermally carbonized SS has attracted special attention in recent years. This work aims to examine the leaching efficiency of P and the consequent release of metals and heavy metals from SS hydrochars (at 180, 215 and 250 °C) using organic acids (oxalate and citrate) over a range of pH values (0–4) and extraction times (5 min-24 h). Both organic acids triggered P extraction efficiencies exceeding 75 % at the lowest pH, but only oxalate reached a nearly complete P release from hydrochars at pH > 0 and for all carbonization temperatures. Low HTC temperature (180 °C) and short extraction time (5 min) were the optimal conditions treatment for P recovery when reacted in oxalate solutions of maximal pH buffering capacity (pH = 1.4). However, oxalate leaching also transferred metals/heavy metals into the P-leachate, with the exception of Ca being retained in the solid residue from HTC as Ca-oxalate precipitate. Different characterization methods confirmed the presence of this precipitate, and provided information about the surface and morphological changes of the SS hydrochars following acid treatment. The results suggest that HTC not only a promising technique to sanitize and reduce the volume of SS, but also an efficient means for P recovery using oxalic acid, thus contributing to the circular economy of P. [ABSTRACT FROM AUTHOR]

The aim of this study was to devise a modification of a temporary anchorage device (TAD) by coating titanium mini screw implants with yttrium stabilized zirconia and to evaluate the insertion torque and surface integrity of it. Five titanium implants (Absoanchor, Dentos, South Korea) from each of the four groups comprising of 6 SH 13-08, 6 SH 13 -10 cylindrical and 6 SH 1312-08, 6 SH 1312-10 tapered mini screw implants were selected to be in the experimental group (Zr Ti) of implants, wherein they were coated with yttrium stabilised zirconia using a RF/DC magnetron sputtering unit. One mini screw implant from each of the four groups remained without coating to serve as control (Ti). After the coating of the titanium mini screw implants, scanning electron microscope (SEM) study was performed to evaluate the thickness and uniformity of the coating obtained. The insertion torque of all implants were evaluated by inserting the implant into bone sample using a manual torque wrench (ADIN). The implants were retrieved from the bone sample and a post insertion SEM study was performed to evaluate any changes in the surface of the Zr-Ti and Ti implants. X-ray diffraction (XRD) analysis was done to confirm the presence of Zirconia in the implants from the experimental group. There was no statistically significant difference between the insertion torque for the zirconia coated mini screw implants and the titanium mini screw implants, where the P value < 0.05 was considered as statistically significant. The values for insertion torque for Zr Ti cylindrical group of 8 mm length ranged from 19-20 N-cm and that for the tapered group of 8 mm length ranged from 15-17 N-cm. The insertion torque for the Zr Ti tapered group of 8 mm ranged from 21-22 N-cm and that of the tapered group ranged from 16-18 N-cm.The insertion torque values for the Ti cylindrical implant for length of 8 mm was 20 N-cm and 21 N-cm for length of 10 mm. The insertion torque values for the Ti tapered implant was 15N-cm for 8 mm length and 16N-cm for 10 mm length. The Zirconia coating on the Titanium mini screw implants was of 2.6 µm in thickness. There was no statistically significant difference in the insertion torque of the Zirconia coated mini screw implants and the non-coated titanium mini screw implants which retained their structural integrity. • Zirconia coated titanium mini screw implants were developed. • Maximum insertion torque and surface characteristics were evaluated. • There observed no change in surface thickness of 2.6 μ between as-received and retrieved zirconia coating over titanium miniscrews. • Maximum insertion torque was higher with cylindrical than tapered ones for both 8 and 10 mm length mini screws. [ABSTRACT FROM AUTHOR]

Stormwater treatment systems such as biofilters could intercept and remove pollutants from contaminated runoff in wildfire-affected areas, ensuring the protection of water quality downstream. However, the deposition of wildfire residues such as ash and black carbon onto biofilters could potentially impair their stormwater treatment functions. Yet, whether and how wildfire residue deposition could affect biofilter functions is unknown. This study examines the impact of wildfire residue deposition on biofilter infiltration and pollutant removal capacities. Exposure to wildfire residues decreased the infiltration capacity based on the amount of wildfire deposited. Wildfire residues accumulated at the top layer of the biofilter, forming a cake layer, but scraping this layer restored the infiltration capacity. While the deposition of wildfire residues slightly changed the pore water geochemistry, it did not significantly alter the removal of metals and E. coli. Although wildfire residues leached some metals into pore water within the simulated root zone, the leached metals were effectively removed by the compost present in the filter media. Collectively, these results indicate that biofilters downstream of wildfire-prone areas could remain resilient or functional and protect downstream water quality if deposited ash is periodically scraped to restore any loss of infiltration capacity following wildfire residue deposition. [Display omitted] • Deposited wildfire residues formed a cake layer that could clog biofilters. • Removing the cake layer can restore biofilter infiltration capacity. • Exposure to wildfire residues did not affect pore water quality parameters. • Deposited residues did not significantly affect the removal of metals, and E. coli. • Deposited wildfire residues did not release metals into treated effluent. [ABSTRACT FROM AUTHOR]

The release of certain metallic constituents within some dental implants could contribute to peri-implantitis and mucositis. While the release rate into surrounding bones and tissues may be dependent on the biocompatibility of dental materials and their designs, the patient's oral hygiene and even the prevalence of certain resident oral bacteria may also affect the service lives of these dental implants by altering their gross corrosion rates. In this study, the levels of Fe, Cr, and Ni released during microbiologically induced intergranular corrosion of medical grade 316L stainless-steel dental material are measured across defined culture durations. Porphyromonas gingivalis , a prominent component of the oral microbiome known to associate with periodontitis and peri-implantitis, is the test bacterium in this study. From the evidence obtained from electrochemical and surface investigations in artificial salivary culture media, dental substates corroded significantly upon maturation of bacterial growth. Corrosion was accompanied by higher levels of metal ion release at extended culture duration. About 1.5 and 9.5 μg/cm2 of Ni and Cr were leached from the metal alloy after a 30-day exposure to the bacterial culture relative to the control; Fe was released 30 times more in the former. This study highlights how oral metal contact influences the corrosion of metallic dental implants (e.g., stainless-steel crowns) in patients infected by certain resident oral bacterium. • Higher amounts of metallic leachants released from dental substrates in salivary culture. • Higher levels of Fe were observed in the culture compared to Ni and Cr. • The above trend continued with and without bacterial inoculation. • Bacterial growth accelerated MIC accompanied by increased j corr and lowered R p. • Intergranular corrosion intensified with evolving volatile sulfur compounds. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the resistance to impingement damage of three different artificially aged UHMWPE materials used for total hip joint replacement. The results obtained can be used as a basis for an acceptance criterion for testing according to ASTM F2582-20. Three different polyethylene liner materials, standard polyethylene (UHMWPE), moderately crosslinked (XLPE) and vitamin E stabilized crosslinked (XLPE-VE) polyethylene of the same design and manufacturer were tested up to one million impingement cycles according to ASTM F2582-20. The liners were artificially oxygen aged for two and three weeks according to ASTM F2003-02. The wear volumes of the liner, acetabular shells, and hip endoprosthesis stems were determined. Each of the six impingement test groups consisted of three samples. For each test group, a reference group was subjected to the same conditioning and loading conditions but without impingement between the hip stem and the liner. The force needed to disassemble the liner from the acetabular shell (push-out force) was determined according to ASTM F1820-22 for the test and the reference groups. XLPE and XLPE-VE polyethylene groups showed less impingement wear when compared to the standard UHMWPE material. Similarly, the protective function of the liner against direct metal-on-metal contact was greater, resulting in less wear on the acetabular shell and the stem neck. The three weeks aged standard UHMWPE group showed early onset of fatigue delamination wear. The push-out values remained unchanged for all XLPE liners and the 3-week aged XLPE-VE liners. The aged UHMWPE liners showed low push-out strength due to component shrinkage caused by aging in combination with the tapered fixation used for this specific design. The largest polyethylene wear volume measured of XLPE and XLPE-VE polyethylene aged for two and three weeks was 15.05 mm³ (SD 0.56 mm³). The corresponding metal wear volume was 1.23 mm³ (SD 0.19 mm³) for the acetabular cup and 1.33 mm³ (SD 0.20 mm³) for the stem neck. Those values can support the definition of an acceptance criteria for impingement testing. The results of the push-out test required by ASTM F2582-20 should be evaluated with respect to geometry changes caused by aging. The protective effect of the polyethylene liner against metal-on-metal contact should be considered in the implant design phase in order to avoid implant failure due to metal debris. [Display omitted] • Cross-linked polyethylene has better wear resistance under impingement conditions than standard polyethylene. • Artificial aging did not deteriorate the impingement resistance of the crosslinked polyethylene. • Three weeks of artificial aging of standard UHMWPE results in early onset of fatigue delamination wear. • Progressive impingement wear can lead to metal abrasion. [ABSTRACT FROM AUTHOR]

Abstract Stainless steel is an important transport and processing contact material for bovine milk and dairy products. Release (migration) of metals, ions, complexes or wear debris/particles, and metal-induced protein aggregation in such environments are hence important to consider both from a corrosion and food safety perspective. This study aims on investigating the release of iron (Fe), chromium (Cr), and nickel (Ni) from AISI 316L stainless steel in contact with whey protein solutions relevant for protein drinks, and on how the whey proteins are influenced by stirring with a magnetic stir bar and metal release. Mechanistic insight is gained by parallel investigations of metal release from two reference non-protein containing solutions, a metal-complexing (citrate-containing) simulated milk solution (SMS) and a low complexing phosphate buffered saline solution (PBS). All immersion exposures were conducted at pH 6.8 for 0.5, 4, 24 and 48 h at room temperature at static and stirring conditions. All solutions and samples were investigated using different chemical, spectroscopic, microscopic, and electrochemical methods. Significantly higher amounts of Fe, Cr, and Ni were released into the whey protein solution (80 g/L) as compared to SMS and PBS. Strong enrichment of Cr in the surface oxide and reduction of the surface oxide thickness were associated with a higher amount of Ni release in the metal-complexing solutions (SMS and whey protein) compared with PBS. Stirring conditions resulted in higher amounts of metal release, enrichment of Cr in the surface oxide, and clear signs of wear of the 316L surface in all solutions compared to static conditions. The wear mechanism in the whey protein solution was different as compared to corresponding processes in SMS and PBS, involving an etching-like process and larger-sized wear debris. Electrochemical measurements at static conditions confirmed observed differences between the solutions, with the lowest corrosion resistance observed for coupons exposed in the whey protein solution, followed by SMS and PBS. Released metals in solution from the 316L coupons in contact with the whey protein solution resulted in enhanced rates of protein aggregation and precipitation of protein aggregates from solution. Further studies should be made to investigate other relevant test conditions and assess toxicological risks. Highlights • Stainless steel – whey protein interactions at static and stirred conditions. • Increased metal release from stainless steel in the presence of whey proteins. • Metal-complexation suggested to contribute to combined degradation mechanisms. • Highest corrosion, metal release, and wear when stirred with whey proteins. • Released metal ions or wear debris/particles induced whey protein aggregation. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Long-term atmospheric corrosion and metal release studies of Sn-bronze and Cu metal at urban and marine environments. • The presence of Sn oxides in the native Cu 2 O rich surface oxide of Sn-bronze improves its barrier properties. • Sn alloying reduces the corrosion rate of Sn bronze at urban conditions. • No beneficial corrosion effects of Sn alloying at chloride-rich marine conditions. • Metal release marginally influenced by Sn alloying. Abstract The role of Sn on the atmospheric corrosion performance of binary Cu-Sn bronze alloys (4–6 wt.% Sn) compared with Cu metal used in outdoor architecture is elucidated in terms of microstructure, native surface oxide composition, patina evolution, corrosion rates, appearance and metal release. Results are presented for non-exposed surfaces and surfaces exposed at different urban and marine sites in Europe up to 5 years and based on multi-analytical findings from microscopic, spectroscopic, electrochemical and chemical investigations. Alloying influenced the corrosion, aesthetic appearance and patina evolution, differently for urban and marine sites, whereas no effects were observed on the release pattern. [ABSTRACT FROM AUTHOR]

Abstract The impact of mechanical disturbance and oxygen induced acidification on the concentration and size fractionation of the 12 metal(loid)s As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sb, Tl, V and the polyatomic nonmetals C, P and S in the pore water was studied. Using the meso profiling and sampling system (messy) 12 pore water depth profiles were sampled from two incubation experiments undertaken in parallel, which were both mechanically disturbed in the lab and subsequently exposed to a different air supply. In parallel to the low invasive, automated sampling process the redox potential, the pH value and the O 2 concentration were detected. Simultaneous quantification of all analytes by inductively coupled plasma-triple quad-mass spectrometry in the two different size classes dissolved (<0.45 μm) and colloidal (0.45–16 μm) showed: i) the predominant influence of the pH on the mobility of metals; ii) the mobility of metalloids was strongly impacted by the mechanical disturbance; and iii) the colloidal release is less important except for Fe, P, and Ni. Graphical abstract Unlabelled Image Highlights • Mobility of 12 metal(loid)s, C, P and S, during disturbances at the SWI was studied • Except for As, Sb, V, mobility of all analytes was more affected by acidification • Mechanical disturbance promoted the mobility of As, Sb, and V • Except for Ni, colloids (0.45–16 μm) were not significant for metal(loid)s mobility • All analytes were quantified by ICP-QQQ-MS in a single run multi-element approach [ABSTRACT FROM AUTHOR]

• Effect of surface finish on corrosion and metal release from Ti6Al4V studied. • Ti6Al4V was produced by laser powder bed fusion using biomedical protocols. • Nitric acid passivation had a negligible effect on metal release and corrosion. • Effect of surface finish (sandblasted, polished) explained by true surface area. • More proteins were adsorbed on rough (sandblasted) surfaces. The biomedical titanium alloy Ti6Al4V has excellent corrosion resistance and biocompatibility and is, therefore, widely used in orthopedic and orthodontic implants. Biomedical implants are increasingly fabricated by additive manufacturing, such as laser powder bed fusion (LPBF). These manufacturing protocols often include sandblasting, surface finish, and passivation. This study aims to investigate the effect of different surface finishes and the commonly used ASTM F86–13 nitric acid passivation for LPBF Ti6Al4V on its corrosion resistance, metal release, and surface changes in benign (bovine serum albumin in a pH 7.4 buffer) and harsh (hydrochloric acid at pH 1.5) solutions using various electrochemical and spectroscopic techniques. Electrochemical, solution and surface analysis showed an insignificant effect of passivation. Smooth surfaces exhibited a slightly better corrosion resistance than rough surfaces due to a 10–20 % smaller true surface area and lower protein adsorption. Implanted ceramic beads from the sandblasting procedure remained on the surface even after the mirror-polishing and passivation procedures. [Display omitted] [ABSTRACT FROM AUTHOR]

Despite being corrosion-resistant, plastic potable water pipes might accumulate heavy metals on their surface if they convey metal-contaminated tap water. This study examined the influence of water pH and flow conditions on lead (Pb) release from new and biofilm-laden potable water pipes to provide insights regarding decontamination. For this purpose, biofilms were grown onto new crosslinked polyethylene (PEX-A), high-density polyethylene (HDPE), and copper pipes for three months. Lead was then deposited onto the new and biofilm-laden pipes through 5 d exposure experiments under flow conditions. After that, lead release experiments were conducted by exposing the lead-accumulated pipes to lead-free synthetic tap water for 5 d, under both stagnant and water flow conditions. The metal accumulation study showed no significant difference in lead uptake by new pipes and their biofilm-laden counterparts under flow conditions. This could be attributed to the detachment of biofilms that have accumulated lead as water flows through the pipes. Water flow conditions significantly influenced the lead release from new and biofilm-laden water pipes. A lower water pH of 5.0 increased the release of lead from plastic pipes into the contact water, compared to pH 6.0 and 7.8. The greatest percentage of lead was released from biofilm-laden HDPE pipes (5.3%, 120 h) compared to biofilm-laden copper pipes (3.9%, 6 h) and PEX-A (3.7%, 120 h) and after exposure to lead-free synthetic tap water at pH 5.0, under stagnant conditions. On the other hand, under water flow conditions, the greatest lead release was found for new PEX-A pipes (4.4%, 120 h), new HDPE pipes (2.7%, 120 h), and biofilm-laden copper pipes (3.7%, 2 h). [Display omitted] • Pb depositions on new and biofilm-laden water pipes were not different under flow conditions. • The lower pH promoted lead release from new plastic and copper potable water pipes. • Biofilm-laden plastic pipes released more Pb than new pipes under stagnant conditions. [ABSTRACT FROM AUTHOR]

The sulphide-rich mine wastes accumulated in tailing dumps of La Concordia Mine (Puna of Argentina) have been exposed to the weathering action for more than 30 years. Since then, a series of redox reactions have triggered the generation of a highly acidic drainage -rich in dissolved metals-that drains into the La Concordia creek. The extent of metal and acid release in the site was analysed through field surveys and laboratory experiments. Static tests were conducted in order to predict the potential of the sulphidic wastes to produce acid, while Cu-, Zn-, Fe- and Pb-bearing phases present in the wastes were identified by XRD, SEM/EDS analysis and sequential extraction procedures. Finally, the release of these metals during sediment-water interaction was assessed in batch experiments carried out in a period of nearly two years. Field surveys indicate that the prolonged alteration of the mine wastes led to elevated electrical conductivity, pH values lower than 4 and metal concentrations that exceed the guide values for drinking water in the La Concordia stream regardless of the dominating hydrological conditions. The highly soluble Fe and Mg (hydrous)sulphates that form salt crusts on the tailings surfaces and the riverbed sediments play an important role in the control of metal mobility, as they rapidly dissolve in contact with water releasing Fe, but also Cu and Zn which are scavenged by such minerals. Another important proportion of the analysed metals is adsorbed onto Fe (hydr)oxides or form less soluble hydroxysulfates. Metals present in these phases are released to water more slowly, thus representing a potential long term source of heavy metal pollution. The obtained results are a contribution to the understanding of long term metal transformations and mobility in mine waste-impacted sites. [ABSTRACT FROM AUTHOR]

The potential release of toxic metals from damaged emerging photovoltaic (PV) cells has raised concerns about the safe use of these new types of PVs. In this study, this concern was addressed by analysing the life cycle toxicity of metals (cadmium, copper, lead, nickel, tin and zinc) that are commonly used in emerging PVs. In estimating the potential metal release, a new model that incorporates field conditions (crack size, time, and glass thickness) and physiochemical properties (diffusion coefficient and solubility product) was introduced. The results show that the use phase toxicity of copper and lead can be higher than the extraction phase toxicity. Thus, precautionary loss limits to manage toxic impacts from the use phase were proposed. Also, the toxicity from different layers of perovskite, copper zinc tin sulphide (CZTS), and quantum dot (QD) type of solar cells was compared. It was found that cadmium sulphide (compared to zinc oxide and tin oxide) and lead (II) sulphide (compared to lead (II) iodine and CZTS) were less toxic alternatives for the electron selective layer and light absorber, respectively. Finally, in comparing the toxic metal releases of the PVs to today's coal power plants, it was seen that the metal emissions from PVs are expected to be several times less than the emissions from coal. [ABSTRACT FROM AUTHOR]

This manuscript evaluates the potential application of active nanocomposite films based on soy protein isolate (SPI)-montmorillonite (MMT)-clove essential oil (CEO) to the preservation of muscle fillets of bluefin tuna ( Thunnus thynnus ) during refrigerated storage, and furthermore analyzes whether the clay diffuses from the package to food. SPI films with: CEO (SPI-CEO), MMT (SPI-MMT), or both CEO and MMT (SPI-MMT-CEO), were prepared and used to cover tuna fillets during 17 days of storage at 2 °C. Polyethylene films were also used as control. Protein films nanoreinforced with 10 g MMT/100 g SPI and activated with CEO were able to decrease microbial growth (evaluated by TVBN and microorganism counts) and lipid autooxidation (evaluated according to the TBA index, FTIR and color parameters) of tuna fillets during the storage period studied. The presence of clay seemed to favor the release of the active principles of clove oil by prolonging its antimicrobial (especially effective to inhibit Pseudomonas spp.) and antioxidant activity over time without observing the diffusion of the clay's own metals (Si and Al) from the nanocomposite materials to the muscle of fish. These results are encouraging for the use of nanocomposite films in food packaging. [ABSTRACT FROM AUTHOR]

This study aimed to characterise the damage mechanisms present on the metal components used in various contemporary total ankle replacements. Twenty-seven explanted total ankle replacements comprising 8 different designs (3 fixed bearing and 5 mobile bearing) were analysed using various explant analysis techniques. Pitting and scratching were the most commonly observed wear features. Microscopic analysis revealed metallic pitting on 52% of tibial components and 95% of talar components. Pitting was identified on more cobalt-chromium than titanium alloy tibial components (63% versus 0%). Non-contact profilometry confirmed the presence of pitting, with significant (p < 0.05) differences in the measured average surface roughness values of pitted and unpitted areas for tibial and talar components. There was macroscopically visible sliding plane scratching, indicating the presence of hard third body particles, on 78% of talar components. Changes to the non-articulating surfaces coatings in terms of coating loss and/or changes in reflectivity was identified visually on 80% of metal components. Scanning electron microscopy with energy dispersive X-ray spectroscopy identified metallic embedded debris in 19% of polyethylene inserts. This explant study demonstrates the release of metal debris from both the metallic tibial and talar component articulating surfaces and non-articulating surface coatings of various contemporary total ankle replacements. Metal particulate debris release from total ankle replacements may be more common than previously recognised. Metal debris should be considered in further study into the aetiology of failed total ankle arthroplasty. [Display omitted] • Pitting is common in cobalt-chromium alloy components. • Third body particles are present in the bearing. • Particulate debris from porous coatings is released. [ABSTRACT FROM AUTHOR]

Seafloor massive sulphide samples from the Trans-Atlantic Geotraverse active mound on the Mid-Atlantic Ridge were characterised and subjected to leaching experiments to emulate proposed mining processes. Over time, leached Fe is removed from solution by the precipitation of Fe oxy-hydroxides, whereas Cu and Pb leached remained in solution at ppb levels. Results suggest that bulk chemistry is not the main control on leachate concentrations; instead mineralogy and/or galvanic couples between minerals are the driving forces behind the type and concentration of metals that remain in solution. Dissolved concentrations exceed ANZECC toxicity guidelines by 620 times, implying the formation of localised toxicity in a stagnant water column. Moreover, concentrations will be higher when scaled to higher rock-fluid ratios and finer grain sizes proposed for mining scenarios. The distance at which dilution is achieved to meet guidelines is unlikely to be sufficient, indicating a need for the refinement of the mining process. [ABSTRACT FROM AUTHOR]

A modified Community Bureau of Reference (CBR) sequential extraction method was tested to assess the composition of untreated pyrogenic carbon (biochar) and oil sands petroleum coke. Wood biochar samples were found to contain lower concentrations of metals, but had higher fractions of easily mobilized alkaline earth and transition metals. Sewage sludge biochar was determined to be less recalcitrant and had higher total metal concentrations, with most of the metals found in the more resilient extraction fractions (oxidizable, residual). Petroleum coke was the most stable material, with a similar metal distribution pattern as the sewage sludge biochar. The applied sequential extraction method represents a suitable technique to recover metals from these materials, and is a valuable tool in understanding the metal retaining and leaching capability of various biochar types and carbonaceous petroleum coke samples. [ABSTRACT FROM AUTHOR]

The weathering process of seafloor massive sulphide (SMS) deposits can be considered analogous to weathering of terrestrial volcanogenic massive sulphides (VMS) deposits. However, in the context of SMS deposits, the process occurs in chemically buffered waters of near neutral pH, resulting in the formation of insoluble Fe oxy-hydroxide minerals including goethite and hematite as well as sulphates such as jarosite. As a result of this precipitation, it is commonly assumed that any SMS deposit is unlikely to exhibit a significant loss of metals (dissolution and release of heavy metals) into the water column. However, galvanic interactions have never been considered in this seafloor context, whilst they have already been shown to have the ability to increase dissolution significantly in terrestrial deposits. If heavy metal release is not temporally balanced by precipitation of oxide phases, there is the potential that these metal occurrences lose economic value. This is specifically significant if there is an industrial focus on exploiting deposits associated with hydrothermal vents that have been inactive for some time. Not only this, but the geochemistry of weathering products – ‘gossans’ – that are formed have the potential to be used as tools for exploration. Furthermore, it is unknown what impact galvanic coupling may have with regards to anthropogenic release of heavy metals during seafloor mining of deposits associated with either active or inactive vents (disturbance of sediment, plume generation and dewatering process). This environmental impact needs to be addressed prior to the formulation of regulations for deep-sea mining by the International Seabed Authority. The present review examines our current understanding of oxidation and dissolution of a mixed sulphide ore, bringing together lines of evidence from a range of literature sources. Based on this review, different seafloor sulphide ore deposits will dissolve by oxidation and release a variety of different metals (economic and/or toxic), all at different rates, with galvanic cells playing a role by increasing dissolution rates. While precipitation of oxide and oxy-hydroxide phases will occur, it is unknown in both a natural weathering and anthropogenic (mining) context whether heavy metal release (including economic and toxic metals) is temporally balanced by this precipitation and any subsequent adsorption. Based on our current understanding, certain sites will be more predisposed to oxidation as a result of their mineralogy (those containing significant pyrrhotite, marcasite, galena and secondary copper sulphides) and/or environment (higher temperatures and oxygen concentrations, lower pH’s). Furthermore, certain sites pose more of an environmental risk (in terms of toxicity) than others, with arc-related SMS deposits associated with higher concentrations of As, Pb, Sb, Cd and Hg and ultra-mafic hosted SMS deposits associated with high concentrations of Co and Ni. The review highlights the need for subsequent studies that investigate the natural weathering process of seafloor sulphide ore deposits, including how this process impacts their economic value and consequent geochemical signature of oxides that are produced over time. Moreover, this review underlines the necessity for experiments to elucidate the oxidative dissolution of ore throughout any mining process. [ABSTRACT FROM AUTHOR]

Studded tyres made of tungsten carbide cobalt (WC-Co) are in the Northern countries commonly used during the winter time. Tungsten (W)-containing nano- and micron-sized particles have been detected close to busy roads in several European countries. Other typical traffic wear particles consist of copper (Cu). The aims of this study were to investigate particle stability and transformation/dissolution properties of nanoparticles (NPs) of WC-Co compared with NPs of tungsten carbide (WC), cobalt (Co), and Cu. Their physicochemical characteristics (primarily surface oxide and charge) are compared with their extent of sedimentation and metal release in synthetic surface water (SW) with and without two different model organic molecules, 2,3- and 3,4-dihydroxybenzoic acid (DHBA) mimicking certain sorption sites of humic substances, for time periods up to 22 days. The WC-Co NPs possessed a higher electrochemical and chemical reactivity in SW with and without DHBA molecules as compared with NPs of WC, Co, and Cu. Co was completely released from the WC-Co NPs within a few hours of exposure, although it remained adsorbed/bonded to the particle surface and enabled the adsorption of negatively charged DHBA molecules, in contrast with the WC NPs (no adsorption of DHBA). The DHBA molecules were found to rapidly adsorb on the Co and Cu NPs. The sedimentation of the WC and WC-Co NPs was not influenced by the presence of the 2,3- or 3,4-DHBA molecules. A slight influence (slower sedimentation) was observed for the Co NPs, and a strong influence (slower sedimentation) was observed for the Cu NPs in SW with 2,3-DHBA compared with SW alone. The extent of metal release increased in the order: WC < Cu < Co < WC-Co NPs. All NPs released more than 1 wt-% of their metal total mass. The release from the Cu NPs was most influenced by the presence of DHBA molecules. [ABSTRACT FROM AUTHOR]

Due to the ignorance by many researchers on the influence of starting microstructure on the metal release of biomedical materials in human body after implant, in this study, the effect of surface friction treatment on the in vitro release of the constituent elements of the biomedical Co–29Cr–6Mo–0.16N (CCM) alloy is investigated for the first time by immersion test in lactic acid solution combined with electron backscatter diffraction, transmission electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, and inductively coupled plasma atomic emission spectroscopy (ICP-EOS). The results indicate that friction treatment on the as-annealed CCM alloy sample surface leads to a planar strain-induced martensitic transformation (SIMT) on sample surface; this greatly accelerates the release of all the constituent elements and, in particular, that of Co as indicated by the ICP-EOS analysis. This increase can be ascribed to a localized deformation that occurred over the entire sample surface, with the dislocation density being high within the SIMTed phase and low in the alloy matrix. [ABSTRACT FROM AUTHOR]

Orthopaedic implants are mostly fabricated by Stainless Steel, Titanium, and Ni-Cr Alloys that consist of Chromium (Cr), Cobalt (Co), Nickel (Ni) and Molybdenum (Mo). 10-15% of population are affected by metals (Ni, Co, Cr, Mo) hypersensitivity reaction. Multilayer coating by Physical Vapour Deposition (PVD) has been applied onto orthopedic implants to prevent metallic ions leaching into human body. This paper aims to study the metal ions leaching of Cr, Ni, Mo, and Co from multilayer coatings of Chromium (Cr), Chromium Nitride (CrN), Chromium Carbonitride (CrCN) and Zirconium Nitride (ZrN) by Physical Vapour Deposition (PVD). Cr, CrN, CrCN and ZrN have been successfully deposited onto stainless steel substrates by CAPVD. XRD analysis detected major peak in preferred orientation of (200) and other peaks with (111), (220), (311) for CrN cubic phase. For CrCN, XRD analysis detected only low intensity peaks of Cr7C3 and ZrN peaks with preferred orientation of (111), (200) with other peak (220), (311) and (222). A seven days metal released test by ICP-MS showed that generally all ions concentration for Ni, Co, Mo decreased from uncoated substrate to multilayer coatings except for Cr. Metal released showed higher concentration for coatings deposition with longer deposition time at 10 minutes. [ABSTRACT FROM AUTHOR]

Pulsed electric field (PEF) technology is an alternative to traditional food processing because this application can ensure good product quality and energy use efficiency. In PEF applications, the functional compounds extracted from food products can be enhanced, and the microorganisms contaminating the food products during processing can be inactivated. These properties are considered advantageous by alcoholic beverage producers. In this review, studies on the PEF treatment of wine, beer, and rice wine are summarized. The PEF technology is used in the pretreatment in grape wine and control of microbial growth in grape wine, beer, and rice wine. In grape wines, the PEF pretreatment can increase phenolic compound and anthocyanin contents and can enhance color intensity; this pretreatment slightly influences the organoleptic characteristics of samples. The PEF technology is also an effective tool to sterilize grape wine, beer, and rice wine. With this application, the quality of these three alcoholic beverages can be ensured because the PEF technology can be applied in the absence of heat. In addition, the main negative effect of PEF technology is discussed as well. [ABSTRACT FROM AUTHOR]

In the study, the microstructure, mechanical property and metal release behavior of selective laser melted CoCrW alloys under different solution treatment conditions were systemically investigated to assess their potential use in orthopedic implants. The effects of the solution treatment on the microstructure, mechanical properties and metal release were systematically studied by OM, SEM, XRD, tensile test, and ICP-AES, respectively. The XRD indicated that during the solution treatment the alloy underwent the transformation of γ-fcc to ε-hcp phase; the ε-hcp phase nearly dominated in the alloy when treated at 1200 °C following the water quenching; the results from OM, SEM showed that the microstructural change was occurred under different solution treatments; solution at 1150 °C with furnace cooling contributed to the formation of larger precipitates at the grain boundary regions, while the size and number of the precipitates was decreased as heated above 1100 °C with the water quenching; moreover, the diamond-like structure was invisible at higher solution temperature over 1150 °C following water quenching; compared with the furnace cooling, the alloy quenched by water showed excellent mechanical properties and low amount of metal release; as the alloy heated at 1200 °C, the mechanical properties of the alloy reached their optimum combination at UTS=1113.6 MPa, 0.2%YS=639.5 MPa, and E %=20.1%, whilst showed the lower total quantity of metal release. It is suggested that a proper solution treatment is an efficient strategy for improving the mechanical properties and corrosion resistance of As-SLM CoCrW alloy that show acceptable tensile ductility. [ABSTRACT FROM AUTHOR]

Sunscreens contain ZnO particles used as a UV filter cause adverse effects in the marine environment through the release of this metal into seawater and its bioaccumulation in organisms. A mathematical model using sunscreen colloidal residues, seawater and R. philippinarum clams as differentiated compartments, is proposed in order to interpret both the kinetic pattern and the bioaccumulation of Zn in clams. Two kinetic laboratory experiments were conducted, both with and without clams exposed to sunscreen concentrations from 0 to 200 mg L−1. Both the lowest value of uptake rate coefficient obtained when 5 mg L−1 of sunscreen is added (0.00688 L g−1 d−1) and the highest obtained at sunscreen addition of 100 mg L−1 (0.0670 L g−1 d−1), predict a lower bioavailability of Zn in a complex medium such as the seawater-sunscreen mixtures, in comparison to those studied in the literature. The efflux rate coefficient from clams to seawater increased from 0 to 0.162 d−1 with the sunscreen concentrations. The estimated value of the inlet rate coefficient at all studied concentrations indicates that there is a negligible colloidal Zn uptake rate by clams, probably due to the great stability of the organic colloidal residue. An equilibrium shift to higher values of Zn in water is predicted due to the bioconcentration of Zn in clams. The kinetic model proposed with no constant Zn (aq) concentrations may contribute to a more realistic prediction of the bioaccumulation of Zn from sunscreens in clams. [Display omitted] • Kinetic model of bioconcentration in clams under varying Zn concentrations • Sunscreen colloidal residues, seawater and clams as three model compartments • The model predicts sharp bioaccumulation rates at sunscreen additions up to 200 mg L−1 • Obtained model parameters contribute to ecotoxicological research [ABSTRACT FROM AUTHOR]

Metals are released during nitrification in drinking water distribution systems; therefore, the release of metal due to nitrification and the relationship between pipe material and water quality variation have been investigated in this research by rotating disk reactors (RDRs). As a result, the extent of nitrification depended on the pipe material; nitrifiers grown on metal surfaces would be unfavorable relative to inert surfaces because of metal toxicity. Results implicate that nitrification could affect water quality and metal release. In RDR with Cu coupons, copper release was accompanied by a decrease in pH and an increase in the nitrite concentration resulting from nitrification. Fe and Zn ions from galvanized steel followed a pattern similar to that of Cu coupons. Stainless steel was identified as the material that was the least influenced by nitrification. As for other metal ions, metal coupons generally released more metal ion when nitrification existed, moreover, it released more metal than plastic pipe whether nitrification exists or not. Electrochemical reactions and acidic environments that result from nitrification may induce these differences. Surprisingly, iron and manganese released from steel material were found to be highly correlated (R = 0.9373), and iron-to-manganese ratio precisely conform to their composition. [ABSTRACT FROM AUTHOR]

In this work, a Multiphysics model based on the Finite Element Method (FEM), was used to study the effect of different electrical parameters as well as chemical composition of the treatment medium on the metal release from the stainless steel (type AISI 316L) electrodes of a PEF chamber. A total of 15 processing conditions obtained by coupling different field strength (12–31 kV/cm) and total specific energy input (20–100 kJ/kg) were simulated with two model liquid food solutions with the same pH (7) and electrical conductivity (2 mS/cm at 25 °C) but different halides concentration. The results showed that the concentration of metallic elements (Fe, Cr and Ni) increased with decreasing the field strength applied or increasing the total specific energy input. These results were attributed to the predominant effect of the pulse frequency, rather than the applied voltage, on the average Faradaic current density values which, in turn, determine the extent of the metal release. Moreover, it was shown that the presence of halides in the composition of the processed product, may lower the breakdown potential and increase the Faradaic current density value which lead to an intense localized metal release from the electrode’s surface. [ABSTRACT FROM AUTHOR]

In pulsed electric field (PEF) processing of liquid foods, unavoidable electrochemical reactions occur, including those involving metal release from the electrodes, which may seriously affect food safety and quality as well as the electrode’s lifetime. The aim of this paper was to set up a mathematical model describing the phenomenon of the metal release from stainless steel (type AISI 316L) electrodes of a continuous flow parallel plate PEF treatment chamber into model liquid foods. The effect of PEF processing variables such as electric field strength, total specific energy input and treatment medium composition on the dynamics of the spatial distribution of the main metallic elements (Fe, Cr and Ni) released from the electrodes in the treatment volume as well as their concentration in the bulk of the product exiting the treatment chamber were simulated. All simulations were performed using a FEM based commercial software (COMSOL Multiphysics™). A validation of the predicted results was carried out and it was demonstrated that the model set up accurately describes phenomenon of metal release at the electrode solution interface. [ABSTRACT FROM AUTHOR]

Intraoral fixed orthodontic appliances are frequently used in the clinical practice of dentistry. They are made from alloys containing different metals at various percentages. The use of these appliances leads to the long-term exposure of patients to these materials, and the potential toxic effects of this exposure raises concerns about patient safety. Thus, the biocompatibility (corrosion behaviour and toxicity) of these materials has to be evaluated prior to clinical use. In the present report, the most recent studies in the scientific literature examining metal ion release from orthodontic appliances and the toxic effects of these ions have been reviewed with a special focus on cytotoxicity and genotoxicity. Previous studies suggest that a case-by-case safety evaluation is required to take into account the increasing variability of materials, their composition and the manufacturing processes. Moreover, in vivo toxicity studies in regard to metal release, cytotoxicity and genotoxicity are still scarce. Therefore, in vitro and in vivo monitoring studies are needed to establish cause-effect relationships between metal ion release and biomarkers of cytotoxicity and genotoxicity. Further investigations could be performed to elucidate the toxic mechanisms involved in the observed effects with a special emphasis on oxidative damage. [ABSTRACT FROM AUTHOR]

Beta-phase Ti-Nb-based alloys are considered as new generation of biomaterials with improved mechanical compatibility for load-bearing implant applications. Small homogeneously dissolved In additions have a positive impact on the elastic properties of beta-type Ti-40Nb. For (Ti-40Nb)-4In the best match between low Young's modulus, high elastic energy and appropriate strength was achieved. In the present study the effect of In addition to Ti-40Nb on the corrosion and passivation behavior in Ringer's solution is assessed by means of potentiodynamic polarization, ICP-OES metal release analysis, XPS and ToF-SIMS for passive film characterization. Like Ti-40Nb, (Ti-40Nb)-4In exhibits very low corrosion rates ( i corr = 0.1–0.2 μA/cm 2 ) and stable anodic passivity ( i pass = 3–4 μA/cm 2 ). Small In additions do not have a detectable effect on the anodic response of the alloy. For both beta-phase alloys metal release rates are below the quantification limits of ICP-OES. Their strong passivating nature is governed by the formation of thin barrier-type Ti- and Nb-oxide films. Passive films on (Ti-40Nb)-4In surfaces which were formed during OCP exposure or anodic polarization comprise oxidized In species (In 2 O 3 , In(OH 3 )). From the viewpoint of corrosion stability (Ti-40Nb)-4In appears to be suitable for implant applications. [ABSTRACT FROM AUTHOR]

In this study, an experimental investigation on fabricating Ni-free CoCrW alloys by selective laser melting (SLM) for dental application was conducted in terms of microstructure, hardness, mechanical property, electrochemical behavior, and metal release; and line and island scanning strategy were applied to determine whether these strategies are able to obtain expected CoCrW parts. The XRD revealed that the γ-phase and ε-phase coexisted in the as-SLM CoCrW alloys; The OM and SEM images showed that the microstructure of CoCrW alloys appeared square-like pattern with the fine cellular dendrites at the borders; tensile test suggested that the difference of mechanical properties of line- and island-formed specimens was very small; whilst the outcomes from the electrochemical and metal release tests indicated that the island-formed alloys showed slightly better corrosion resistance than line-formed ones in PBS and Hanks solutions. Considering that the mechanical properties and corrosion resistance of line-formed and island-formed specimens meet the standards of ISO 22674:2006 and EN ISO 10271, CoCrW dental alloys can be successfully fabricated by line and island scanning strategies in the SLM process. [ABSTRACT FROM AUTHOR]

Mangrove forests have been reported as sinks for metals because of the immobilization of these elements in their soils. However, climate change may alter the functioning of these ecosystems. We aimed to assess the geochemical dynamics of Mn, Cu, and Zn in the soils of a mangrove forest dead by an extreme weather event in southeastern Brazil. Soil samples were collected from dead and live mangroves adjacent to each other. The physicochemical parameters (total organic carbon, redox potential, and pH), total metal content, particle size, and metal partitioning were determined. Distinct changes in the soil geochemical environment (establishment of suboxic conditions) and a considerable loss of fine particles was caused by the death of the mangroves. Our results also showed a loss of up to 93 % of metals from soil. This study highlights the paradoxical role of mangroves as potential metal sources in the face of climate change. [Display omitted] • Death of mangrove forests causes more oxidizing soil conditions. • Death of mangrove trees leads to loss of fine soil particles. • Dead mangrove forests lose up to 90 % of metals from its soils. • Extreme weather events may shift mangrove forests into metal sources. [ABSTRACT FROM AUTHOR]

To ensure the safety of metals and alloys intended for food contact, a new European test protocol (CoE protocol) using citric acid as a food simulant was published in 2013. This study investigated the influence of citric acid and exposure conditions on the metal release from an austenitic manganese stainless steel (AISI 201). Exposures in 5 g/L citric acid resulted in significantly lower metal releases compared with specific release limits set by the CoE protocol. 5 g/L (0.3 vol%) citric acid was more aggressive than 3 vol% acetic acid (Italian protocol) due to higher metal complexation. Studies on abraded surfaces revealed that most metals were released during the first 0.5 h of exposure due to surface passivation. Surface abrasion, increased temperature (40–100 °C), increased surface area to solution volume ratio (0.25–2 cm 2 /mL) and increased citric acid concentration (0–21 g/L) all resulted in increased released metal quantities. [ABSTRACT FROM AUTHOR]

This study examined the behavior of corrosion potential (Ecorr) of iron exposed to drinking water during episodes of stagnation and flow. These measurements showed that during stagnation episodes, Ecorr values decrease prominently and consistently. This decrease is initially rapid but it becomes slower as the stagnation time increases. During flow episodes, the Ecorr values increase and reach a quasi-steady state. Experiments with varying concentrations of dissolved oxygen showed that the decrease of Ecorr values characteristic for stagnation is likely to be associated with the consumption of dissolved oxygen by the exposed metal. The corrosion potential of iron and its changes during stagnation were sensitive to the concentrations of sulfate and chloride ions. Measurements of iron release showed that both the absolute values of Ecorr measured prior to or after stagnation episodes were well correlated with the logarithms of concentrations of total iron. The slope of this dependence showed that the observed correlations between Ecorr values and Fe concentrations corresponded to the coupling between the oxidant consumption and changes of Fe redox status. These results demonstrate that in situ Ecorr measurements can be a sensitive method with which to ascertain effects of hydrodynamic conditions and short-term variations of water chemistry on metal release and corrosion in drinking water. This approach is valuable practically because Ecorr measurements are precise, can be carried out in situ with any desired time resolution, do not affect the state of exposed surface in any extent and can be carried out with readily available equipment. [ABSTRACT FROM AUTHOR]

Stainless steel is widely used in biological environments, for example as implant material or in food applications, where adsorption-controlled ligand-induced metal release is of importance from a corrosion, health, and food safety perspective. The objective of this study was to elucidate potential correlations between surface energy and wettability of stainless steel surfaces and the release of iron in complexing biological media. This was accomplished by studying changes in surface energies calculated from contact angle measurements, surface oxide composition (X-ray photoelectron spectroscopy), and released iron (graphite furnace atomic absorption spectroscopy) for stainless steel grade AISI 304 immersed in fluids containing bovine serum albumin or citric acid, and non-complexing fluids such as NaCl, NaOH, and HNO 3 . It was shown that the surface wettability and polar surface energy components were all influenced by adventitious atmospheric carbon (surface contamination of low molecular weight), rather than differences in surface oxide composition in non-complexing solutions. Adsorption of both BSA and citrate, which resulted in ligand-induced metal release, strongly influenced the wettability and the surface energy, and correlated well with the measured released amount of iron. [ABSTRACT FROM AUTHOR]

Highlights: [•] Influence of low-temperature carburising (LTC) on metal release in acetic acid 3vol.%. [•] LTC-treated steel releases higher alloying metal amounts than untreated steel. [•] Fe, Cr, Ni and Mn release higher than the WHO guideline values for drinking-water quality. [ABSTRACT FROM AUTHOR]

This study provides a better knowledge of key parameters controlling the mobility of Dissolved Organic Carbon (DOC), As, Cd, Cr, Cu, Ni, Pb and Zn from contaminated marine sediment in contact with acidified seawater using static and dynamic standard leaching tests. These procedures have been modified in order to use different leaching agents, L/S ratios, contact times and pH values that simulate seawater acidification under CO2 leakages scenarios. Studied sediment from a potential area of CO2 storage, shows a high acid neutralisation capacity (ANCpH=4=3.58 eq/kg) for deionised water as well as for seawater (ANCpH=4=3.97 eq/kg). The availability control mechanism is shown by releasing Cd with seawater at pH values 6, 7 and 8 and by the releasing of Zn with seawater at pH 6; the solubility control mechanism appears for Ni release using natural seawater. Experimental results of metal release from the pH dependence leaching test are modelled with Visual MINTEQ geochemical software to predict metal release from sediment, obtaining minor differences with experimental values. An improvement in the metal release results has been obtained considering in the model the influence of the DOC, Fe- and Al-(hydr)oxides, humic acids and fulvic acids. The obtained results would be useful as a line of evidence input for the risk assessment of a Carbon Capture and Storage site where acidified seawater at different concentrations of CO2 is in contact with sediment. [ABSTRACT FROM AUTHOR]

Abstract: Size-dependent health aspects due to exposure to micro- or nano-sized particles can only be fully understood if their physicochemical properties are well characterized. The aim of this study was to explain the process of metal release from well-characterized inert gas atomized stainless steel 316L particles, sized<4µm (fine) and<45µm (coarse), in aggressive environments of relevance for inhalation and cellular uptake. This was accomplished by correlating new results from real-time metal release measurements with particle- and surface oxide characteristics. In simulated biological media with complexing properties, a complexation (ligand)-induced dissolution mechanism is dominating the metal release from fine 316L particles (having a homogeneous and amorphous Mn-rich surface oxide due to rapid cooling). At similar conditions, the coarse 316L particles show a metal release mechanism dominated by fast dissolution of surface oxide nanoparticles (rich in Mn, Fe, and some S), acting as initiation sites for metastable pitting corrosion. [Copyright &y& Elsevier]

Abstract: Objective: Selective laser melting (SLM) is increasingly used for the fabrication of customized dental components made of metal alloys such as CoCrMo. The main aim of the present study is to elucidate the influence of the non-equilibrium microstructure obtained by SLM on corrosion susceptibility and extent of metal release (measure of biocompatibility). Methods: A multi-analytical approach has been employed by combining microscopic and bulk compositional tools with electrochemical techniques and chemical analyses of metals in biologically relevant fluids for three differently SLM fabricated CoCrMo alloys and one cast CoCrMo alloy used for comparison. Results: Rapid cooling and strong temperature gradients during laser melting resulted in the formation of a fine cellular structure with cell boundaries enriched in Mo (Co depleted), and suppression of carbide precipitation and formation of a martensitic ɛ (hcp) phase at the surface. These features were shown to decrease the corrosion and metal release susceptibility of the SLM alloys compared with the cast alloy. Unique textures formed in the pattern of the melting pools of the three different laser melted CoCrMo alloys predominantly explain observed small, though significant, differences. The susceptibility for corrosion and metal release increased with an increased number (area) of laser melt pool boundaries. Significance: This study shows that integrative and interdisciplinary studies of microstructural characteristics, corrosion, and metal release are essential to assess and consider during the design and fabrication of CoCrMo dental components of optimal biocompatibility. The reason is that the extent of metal release from CoCrMo is dependent on fabrication procedures. [Copyright &y& Elsevier]

Abstract: Bare copper sheet and three commercial Cu-based alloys, Cu15Zn, Cu4Sn and Cu5Al5Zn, have been exposed to four test sites in Brest, France, with strongly varying chloride deposition rates. The corrosion rates of all four materials decrease continuously with distance from the coast, i.e. with decreasing chloride load, and in the following order: Cu4Sn>Cu sheet>Cu15Zn>Cu5Al5Zn. The patina on all materials was composed of two main layers, Cu2O as the inner layer and Cu2(OH)3Cl as the outer layer, and with a discontinuous presence of CuCl in between. Additional minor patina constituents are SnO2 (Cu4Sn), Zn5(OH)6(CO3)2 (Cu15Zn and Cu5Al5Zn) and Zn6Al2(OH)16CO3·4H2O/Zn2Al(OH)6Cl·2H2O/Zn5Cl2(OH)8·H2O and Al2O3 (Cu5Al5Zn). The observed Zn- and Zn/Al-containing corrosion products might be important factors for the lower sensitivity of Cu15Zn and Cu5Al5Zn against chloride-induced atmospheric corrosion compared with Cu sheet and Cu4Sn. Decreasing corrosion rates with exposure time were observed for all materials and chloride loads and attributed to an improved adherence with time of the outer patina to the underlying inner oxide. Flaking of the outer patina layer was mainly observed on Cu4Sn and Cu sheet and associated with the gradual transformation of CuCl to Cu2(OH)3Cl of larger volume. After three years only Cu5Al5Zn remains lustrous because of a patina compared with the other materials that appeared brownish–reddish. Significantly lower release rates of metals compared with corresponding corrosion rates were observed for all materials. Very similar release rates of copper from all four materials were observed during the fifth year of marine exposure due to an outer surface patina that with time revealed similar constituents and solubility properties. [Copyright &y& Elsevier]

Abstract: The effects of electrical parameters (field strength E, total specific energy input WT and pulse frequency) and product composition on the release of the main metallic elements (Fe, Cr, Ni and Mn) of stainless steel (type 316L) electrodes of a continuous flow parallel plate PEF chamber into the treatment medium were investigated. Experiments were carried out by subjecting two different buffer solutions (McIlvaine and Trizma-HCl) with the same values of pH (7) and electrical conductivity (σ=2mS/cm) to PEF treatments (mono-polar exponential decay pulses, lasting 3.1μs) at different intensities (E=12–21–31kV/cm, WT =20–60–100J/mL) and flow rates (2–3–4L/h). The results showed that, for each field strength applied, the concentration of metallic elements increased upon increasing the total specific energy input. At constant total energy input, it was noticed that the metal concentration decreased upon increasing the field strength applied. These results were mainly attributed to the key role played by the pulse frequency in the charging process of the double layer capacitors at the electrode–solution interface. Moreover, it was shown that the amount of metal released from the electrodes markedly depended on the presence of halides in the composition of the processed product. Industrial relevance : Electrochemical reactions at the electrode solution interfaces are unavoidable when typical conditions for PEF processing are applied. For the acceptability of PEF processing as a non-thermal method for liquid food pasteurization, the occurrence of these reactions should be avoided or minimized since they may determine undesired phenomenon of contamination of the food product, electrode-fouling and electrode corrosion. In this paper, electrode corrosion was studied, for the first time, in a continuous flow parallel plate PEF treatment chamber. The present investigation contributes to clarifying the effects of some electrical parameters and food composition on electrode corrosion or release of electrode materials under real PEF treatment conditions. [Copyright &y& Elsevier]

Abstract: Cu-containing nanoparticles are used in various applications in order to e.g. achieve antimicrobial activities and to increase the conductivity of fluids and polymers. Several studies have reported on toxic effects of such particles but the mechanisms are not completely clear. The aim of this study was to investigate the interactions between cell membranes and well-characterized nanoparticles of CuO, Cu metal, a binary Cu-Zn alloy and micron-sized Cu metal particles. This was conducted via in vitro investigations of the effects of the nanoparticles on (i) cell membrane damage on lung epithelial cells (A549), (ii) membrane rupture of red blood cells (hemolysis), complemented by (iii) nanoparticle interaction studies with a model lipid membrane using quartz crystal microbalance with dissipation monitoring (QCM-D). The results revealed that nanoparticles of the Cu metal and the Cu-Zn alloy were both highly membrane damaging and caused a rapid (within 1h) increase in membrane damage at a particle mass dose of 20μg/mL, whereas the CuO nanoparticles and the micron-sized Cu metal particles showed no such effect. At similar nanoparticle surface area doses, the nano and micron-sized Cu particles showed more similar effects. The commonly used LDH (lactate dehydrogenase) assay for analysis of membrane damage was found impossible to use due to nanoparticle-assay interactions. None of the particles induced any hemolytic effects on red blood cells when investigated up to high particle concentrations (1mg/mL). However, both Cu and Cu-Zn nanoparticles caused hemoglobin aggregation/precipitation, a process that would conceal a possible hemolytic effect. Studies on interactions between the nanoparticles and a model membrane using QCM-D indicated a small difference between the investigated particles. Results of this study suggest that the observed membrane damage is caused by the metal release process at the cell membrane surface and highlight differences in reactivity between metallic nanoparticles of Cu and Cu-Zn and nanoparticles of CuO. [Copyright &y& Elsevier]

Abstract: Weathering of sulphide minerals produces a large variety of Fe-oxide-bearing ochreous, varicoloured precipitates and efflorescences of variably soluble sulphate salts. These secondary minerals play an important role in acid mine drainage processes and, more generally, for environmental pollution, since they can be either a sink or a source for acidity and toxic metals. At Libiola mine, eastern Liguria (Italy), the secondary minerals directly form through precipitation from acid sulphate waters within waste-rock dumps and outcropping mineralized bodies as well as within streams and runoff channels. Within waste-rock dumps they are present mainly as cement, filling the inter-clast porosity, and/or as coating and ephemeral efflorescences on the outcropping surfaces. Their stability represents a major environmental issue due to the potential importance of these phases in controlling metal distribution in the surface environment. This paper presents a detailed mineralogy and geochemistry characterisation of these materials, investigating the tendency for different types of secondary minerals (hardpans, ochreous consolidated precipitates, ochreous colloids, non ochreous colloids) to release metals after a simple mixing with deionised water for 12days. Within the different types of deposits, hardpans showed the lowest tendency to release metals, in contrast to ochreous colloids and ochreous concretions that gave the highest concentrations. Nickel was the element most easily extracted by this treatment, even from non-ochreous colloids, while iron was much less readily leached. Dissolution experiments carried out on efflorescent sulphate salts demonstrated that these materials have a strong acid producing affinity which led to their complete dissolution. These results indicate that secondary phases associated with acid mine drainage can play an important role in controlling trace metal mobility, acting either as scavengers, to remove metals, from solutions or also as secondary sources of metal contamination during the interaction of these materials with surface waters. [Copyright &y& Elsevier]

Highlights: [•] Concentration and speciation of metals released from fly ash. [•] Effects of dredging and ash recovery on metals. [•] Metals speciation through recovery operations. [•] Fate and transformation in aqueous systems. [Copyright &y& Elsevier]

Abstract: Highly porous 17-4 PH stainless steel foam for biomedical applications was produced by space holder technique. Metal release and weight loss from 17–4 PH stainless steel foams was investigated in simulated body fluid and artificial saliva environments by static immersion tests. Inductively coupled plasma-mass spectrometer was employed to measure the concentrations of various metal ions released from the 17-4 PH stainless steel foams into simulated body fluids and artificial saliva. Effect of immersion time and pH value on metal release and weight loss in simulated body fluid and artificial saliva were determined. Pore morphology, pore size and mechanical properties of the 17-4 PH stainless steel foams were close to human cancellous bone. [Copyright &y& Elsevier]

The pH change and the release of organic matter and metals from sediment, due to the potential CO2 acidified seawater leakages from a CCS (Carbon Capture and Storage) site are presented. Column leaching test is used to simulate a scenario where a flow of acidified seawater is in contact with recent contaminated sediment. The behavior of pH, dissolved organic carbon (DOC) and metals As, Cd, Cr, Cu, Ni, Pb, Zn, with liquid to solid (L/S) ratio and pH is analyzed. A stepwise strategy using empirical expressions and a geochemical model was conducted to fit experimental release concentrations. Despite the neutralization capacity of the seawater-carbonate rich sediment system, important acidification and releases are expected at local scale at lower pH. The obtained results would be relevant as a line of evidence input of CCS risk assessment, in an International context where strategies to mitigate the climate change would be applied. [Copyright &y& Elsevier]

Abstract: Ultramafic rocks and their related soils and sediments are non-anthropogenic sources of metal contaminants. In the southeastern region of Sri Lanka, release of Ni and Mn into the surrounding areas and groundwater is an ecological, agricultural and human health concern. Here, we investigate the release and fate of Ni and Mn from serpentine sediment in the Ussangoda ultramafic complex by coupling interpretations garnered from chemical extractions. Sequential extraction experiments, utilized to identify ‘elemental pools,’ indicate Mn is mainly associated with oxides/(oxy)hydroxides, whereas, Ni is bound in silicates and spinels. Both Ni and Mn demonstrate rapid release rates in water (2.4×10−12 and 2.0×10−13 molm−2 s−1, respectively) and release rates increase with increasing ionic strengths. Sediments evaluated from 0.05 to 10mM with organic (citric, acetic and oxalic) and inorganic (H2SO4, HNO3 and HCl) acids show that the maximum rate of Ni and Mn release occurs with oxalic acid (10mM) at 7.11×10−11 and 3.56×10−11 molm−2 s−1, respectively. Summarizing chemical extractions, Ni and Mn release rates increase in the order of HNO3 ≈HCl≈acetic

Abstract: Corrosion-induced tin and iron release were investigated by inductively coupled plasma mass spectrometer (ICP-MS) and a novel electrochemical sensor. The sensor was used for detecting the corrosion extent of energy drink cans by techniques of electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN), and a metal release mechanism was proposed. ICP-MS results showed that tin and iron release increased with the storage time while EIS and EN results showed that coating resistance, charge transfer resistance and noise resistance decreased with the storage time, which indicated that the corrosion beneath the organic coating induced metal release. Consequently, a clear and direct relationship was obtained between the ICP-MS and the electrochemical results. Furthermore, the internal surface morphology of the cans was characterized by scanning probe microscopy (SPM). It was concluded that the novel electrochemical sensor that allowed in situ measurement could be used for the evaluation of corrosion extent and metal release in beverage cans in a more economical and rapid way. [Copyright &y& Elsevier]

Abstract: This study explores the initial release of zinc and aluminum from non-treated Galvalume and the parallel formation of corrosion products when exposed to synthetic seawater and rainwater of different chloride content. Comparisons were made with long-term field exposures at non-sheltered marine conditions. Observed release rates from short-term conditions agree qualitatively with the long-term findings with a selective release of zinc over aluminum. The release and corrosion processes were intertwined through the formation of corrosion products with properties that influence the long-term release process. Prior to exposure, Al2O3 dominated the entire surface, and was subject to local destruction upon interaction with chloride ions. As a consequence Al2O3 was gradually replaced and covered by zinc-rich corrosion products primarily in interdendritic areas during the first year of marine exposure. This was followed by the gradual formation and integration of aluminum-rich corrosion products, reflected by an increased zinc release rate during the first year, followed by a gradually decreased rate during subsequent years. The importance of Al2O3 was also evident in deaerated synthetic rainwater or seawater, where the formation of Al2O3 was presumably hindered. In synthetic rain water this resulted in a higher ratio between released aluminum and zinc compared with non-deaerated conditions. [Copyright &y& Elsevier]