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Total element concentrations by themselves are not always good predictors of toxicity and are therefore not suitable for eco- and/or human toxicological risk determination. In addition, despite the growing call for harmonization, countries show significant variation in risk assessment tools, screening/background values, protocols and legal management of soils. By incorporating mobility and bioaccessibility/availability into soil risk assessments, location-specific physico-chemical and geological conditions can be considered in routinely applied general risk assessment methodologies. Minette soils and rocks are a great case in point since they often are associated with high geogenic As concentrations and consequently potential risks. Minette iron ores form the world largest Fe ore deposits since the “great oxidation”. For the first time, oral bioaccessibility during direct ingestion was assessed on Minettes from Luxembourg by applying the in vitro Solubility/Bioavailability Research Consortium (SBRC) method. Out of > 180 samples, 25 representative samples were selected providing a unique dataset which showed an average gastric bioaccessibility of ∼10% (7.8 ± 4.0 mg/kg) of the total As-concentration, with a maximum of 45% (17.9 mg/kg). Of importance is that bioaccessibility of As in Minette rocks and soils are controlled by, and can be estimated from, lithology, mineralogy and total Ca content. Soils and ooid grainstones with an iron oxide or clayey matrix, are characterized by average gastric bioaccessible As concentrations

In this research, fifteen potentially toxic elements (PTEs) (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Sc and Zn) were analysed and quantified in samples collected at 44 sites in an urban area of Iran. Sources were apportioned using enrichment factors (EFs), modified pollution index (MPI), principal component analysis (PCA), multivariate linear regression of absolute principal component scores (MLR-APCS) and speciation, with a focus on anthropogenic PTEs in the urban and industrial soils of the Arvand Free Zone area, an oil-rich zone in the country. Furthermore, the bioaccessibility and the human health risks of PTEs were investigated. The EF revealed a significant enrichment for elements such as Cd, Cu, Hg, Mo, Pb, Sb and Zn. Values of MPI showed that Abadan industrial district and Abadan petrochemical complex are the most polluted sites in the study area. The PCA/MLR analysis revealed four main sources: natural sources, fossil fuel combustion, traffic and oil derivatives and petroleum waste. The relative contribution of each source to PTE concentration varied from 32.3% of the natural sources to 30.6% of traffic and from 20.1% of petroleum waste to 17% of fossil fuel combustion. The source apportionment of metals generated using MLR-APCS receptor modelling revealed that 85.0% of Hg was generated by oil products. Chemical speciation results were compatible with the results obtained from PCA. Bioaccessibility of PTEs decreased from gastric to intestinal phase except Mo and Sb due to their different geochemical characteristics. Hazard index (HI) for non-cancer risk of PTEs for both children and adults based on total element concentrations was estimated to range from 2-fold to more than 10-fold higher than that of bioaccessible phases. [ABSTRACT FROM AUTHOR]

Total element concentrations by themselves are not always good predictors of toxicity and are therefore not suitable for eco- and/or human toxicological risk determination. In addition, despite the growing call for harmonization, countries show significant variation in risk assessment tools, screening/background values, protocols and legal management of soils. By incorporating mobility and bioaccessibility/availability into soil risk assessments, location-specific physico-chemical and geological conditions can be considered in routinely applied general risk assessment methodologies. Minette soils and rocks are a great case in point since they often are associated with high geogenic As concentrations and consequently potential risks. Minette iron ores form the world largest Fe ore deposits since the "great oxidation". For the first time, oral bioaccessibility during direct ingestion was assessed on Minettes from Luxembourg by applying the in vitro Solubility/Bioavailability Research Consortium (SBRC) method. Out of > 180 samples, 25 representative samples were selected providing a unique dataset which showed an average gastric bioaccessibility of ∼10% (7.8 ± 4.0 mg/kg) of the total As-concentration, with a maximum of 45% (17.9 mg/kg). Of importance is that bioaccessibility of As in Minette rocks and soils are controlled by, and can be estimated from, lithology, mineralogy and total Ca content. Soils and ooid grainstones with an iron oxide or clayey matrix, are characterized by average gastric bioaccessible As concentrations < 6 mg/kg. Gastric As bioaccessibility is highest in Fe-bearing calcite-cemented bioclastic grainstones (∼12 mg/kg). Importantly, for all samples the maximal bioaccessible As concentrations remain below the threshold from which significant adverse non-carcinogenic and/or carcinogenic health effects are expected. These new results are in strong contrast with what total As concentrations might suggest. Considering bioaccessibilities, consequently, can help to avoid disproportionate, costly and environmentally impacting risk management strategies. Furthermore, this study illustrates the importance of cross-disciplinary collaboration between geo- and health scientists. [Display omitted] ● Human health risks nearby As-bearing Minette soils or rocks were evaluated. ● Lithology, mineralogy and Ca content proved to be good predictors of SBRC bioaccessibility. ● The maximal SBRC bioaccessible As concentration was below 17.9 mg/kg. ● Bioavailability estimation was essential to accurately assess health risks. ● Analyses indicated no significant adverse non-carcinogenic or carcinogenic health effects. [ABSTRACT FROM AUTHOR]

The Brazilian symposium on computer networks and distributed systems (SBRC) reached its 30th edition as the paramount scientific event in the area of computer networks and distributed systems in Brazil. Faced with this opportune moment in the event's history, we here study the collaboration network established among authors who have jointly published in the symposium. Towards that end, we collected bibliographic data from all 30 editions, and built the co-authorship network of the event. We then analyzed the network structural features and evolution throughout its history. Our results reveal the main kind of co-author relationship among authors, show the most prominent communities within SBRC, the regions of Brazil that attracts the most authors, the researchers with central roles in the network as well as the importance of inter-state collaborations. Finally, we align our results with historical facts that may have had a key impact on the symposium success. [ABSTRACT FROM AUTHOR]

The bioaccessibility of arsenic, cadmium, chromium, copper, lead, nickel, and zinc in four National Institute of Standards and Technology (NIST) standard reference materials and two Canadian dust samples as determined using the Solubility/Bioavailability Research Consortium (SBRC)in vitroprocedure ranged from a low of 1.8% for chromium in standard reference material NIST 2711 to a high of 95.2% for cadmium in NIST 2584. The SBRC data were compared to data generated using a modified EN-71 Toy Safety protocol conducted at two different laboratories. Results for the two extraction methods compared well with differences between the means (SBRCvs.modified EN-71) generally less than 10% for the majority of the metals. These differences between the two extraction methods were negligible compared to variability caused by (a) the inherent heterogeneity of typical house dust samples and (b) differences in ICP-MS analytical approaches employed in the different laboratories. Results indicate that the modified EN-71 method is useful and appropriate as a relatively simple, rapid, and reproducible screening test for estimating metals’ bioaccessibility in soil and dust samples. [ABSTRACT FROM AUTHOR]

Abstract: The impact of soil particle size and bioaccessibility on children and adult lead (Pb) exposure via the incidental soil ingestion pathway was assessed in 16 peri-urban contaminated soils. A comparison of Pb distribution across 4 particle size fractions (<50μm, <100μm, <250μm and <2mm) found increasing Pb concentrations associated with decreasing particle size fractions. Lead enrichment in the <50μm particle size fraction was up to 5 times the concentration observed in the bulk soil. When gastric phase Pb bioaccessibility was determined in the <50, <100 and <250μm particle size fractions using the SBRC assay, Pb bioaccessibility also increased with decreasing particle size fraction for 6 of the 16 soils tested. Assessment of children and adult Pb exposure indicated that particle size and bioaccessibility had a significant influence on the contribution of incidental soil ingestion to daily Pb intake values. Although the <250μm particle size fraction is recommended for incidental soil ingestion calculations, using this fraction has the potential to underestimate Pb exposure due to the preferential adhesion of smaller particles to hands with elevated Pb concentrations. [Copyright &y& Elsevier]

Abstract: Lead (Pb) bioaccessibility was assessed in a range of peri-urban soils (n =31) with differing sources of Pb contamination, including shooting range soils, and soils affected by incinerator, historical fill, mining/smelting, and gasworks activities. A gossan soil sample was also included. Lead bioaccessibility was determined using both gastric and intestinal phases of the SBRC in vitro assay and in vitro data was then incorporated into in vivo–in vitro regression equations to calculate Pb relative bioavailability. Lead bioaccessibility ranged from 26.8–105.2% to 5.5–102.6% for gastric and intestinal phase extractions respectively. Generally, Pb bioaccessibility was highest in the shooting range soils and lowest in the gossan soil. Predictions of relative Pb bioavailability derived from in vitro data were comparable for shooting ranges soils, but highly variable for the other soils examined. For incinerator, historical fill, gasworks and gossan soils, incorporating in vitro gastric data into the in vivo–in vitro regression equation resulting in more conservative Pb relative bioavailability values than those derived using the intestinal in vitro data. [Copyright &y& Elsevier]

This study was conducted to investigate the contribution of a site-specific bioavailability of arsenic (As) to human health risk at an old abandoned smelter site in Korea. The site was contaminated with As for over 60 years with the same source (As2O3 in flue gas), but concentration and in vitro bioaccessibility (IVBA) of As differed by operable units (OU), which consequently resulted in difference in estimated risk. Soil samples collected from six OUs showed that aqua regia-extractable As concentrations ranged from 9.8 to 52.8mg/kg (average 34.1mg/kg) at OUs 1-5, which had been used as rice paddy field and farmland, and a forest region OU 6 showed much higher As concentrations (14.4-169.8mg/kg, average 85.9mg/kg). IVBA of As, determined from the ratio of Solubility/Bioavailability Research Consortium (SBRC)-extractable As to aqua regia-extractable As had a wide range of values (90th percentile values of 28.2-65.8%). Carcinogenic risk calculated with total soil As concentration was the highest (1.4×10(-4)) at OU 6 and the risk at the other OUs ranged from 3.8×10(-5) to 5.7×10(-5). In contrast, when site-specific relative bioavailability (i.e., IVBA values) was incorporated, the estimated risk was reduced by 29.5-62.0% and the decrease was the highest at OUs 1 and 5 with the lowest IVBA of 28.2%. The results demonstrate that the chemical forms of As may be different although the source of contamination is similar, and site-specific bioavailability affected by the chemical forms is an important factor in determining human health risk., (Copyright © 2014 Elsevier Inc. All rights reserved.)