Aquatic Ecosystem Risk Assessment Generated by Accidental Silver Nanoparticle Spills in Groundwater.

This paper aims to create a new model for assessing the ecosystem risk in rivers and wetlands that are linked to accidental spills of silver nanoparticles (AgNPs) in soil/groundwater. Due to the uncertainty of the modeling inputs, a combination of two well-known risk assessment methodologies (Monte Carlo and fuzzy logic) were used. To test the new model, two hypothetical, accidental AgNP soil spill case studies were evaluated; both of which were located at the end of the Llobregat River basin within the metropolitan area of Barcelona (NE Spain). In both cases, the soil spill reached groundwater. In the first case, it was discharged into a river, and in the second case, it recharged a wetland. Concerning the results, in the first case study, a medium-risk assessment was achieved for most cases (83%), with just 10% of them falling below the future legal threshold concentration value. In the second case study, a high-risk assessment was obtained for most cases (84%), and none of the cases complied with the threshold value. A sensitivity analysis was conducted for the concentration and risk. The developed tool was proven capable of assessing risk in aquatic ecosystems when dealing with uncertain and variable data, which is an improvement compared to other risk assessment methodologies.

Functionalization of Screen-Printed Electrodes with Grape Stalk Waste Extract-Assisted Synthesized Silver and Gold Nanoparticles: Perspectives of Electrocatalytically Enhanced Determination of Uranyl Ion and Other Heavy Metals Ions.

Recently, nanotechnology and nanoparticles (NPs) such as AgNPs and AuNPs have become important in analytical chemistry due to their great potential to improve the performance of electrochemical sensors. In this work, Ag and Au nanoparticles have been synthesized using a green route in which a grape stalk waste extract is used as a reducing agent to obtain metallic nanoparticles. These NPs were used to customize the surface of commercial screen-printed electrodes (SPCNFEs). The spin-coating method was used to modify commercial SPCNFEs under a nitrogen atmosphere. The resulting electrodes were used in a determination study of Cd(II), Pb(II), and U(VI) with differential pulse anodic stripping voltammetry (DPASV). The customized green AgNPs and AuNPs electrodes presented higher sensitivity and electroanalytical performance than the non-modified SPCNFE. The results showed that the best analytical parameters were obtained with the green, silver nanoparticle SPCNFEs, with a LOD of 0.12 µg L-1 for Pb(II), which is a lower value compared to the most restrictive regulation guidelines. Additionally, the U(VI) ion was successfully determined using the developed G-AgNPs-SPCNFE in spiked tap water, showing comparable results with the ICP-MS technique.

Direct As(V) Determination Using Screen-Printed Electrodes Modified with Silver Manoparticles.

Carbon-nanofiber-based screen-printed electrodes modified with silver nanoparticles (Ag-NP-SPCNFEs) were tested in a pioneering manner for the direct determination of As(V) at low µg L-1 levels by means of differential pulse anodic stripping voltammetry. Screen-printed electrodes were modified with two different types of Ag-NPs, nanoseeds (NS), and nanoprisms (NPr) and characterized both microscopically and electrochemically. Furthermore, after optimizing the direct voltammetric determination of As(V), the analytical performance of considered sensors was compared for the direct determination of As(V). These results suggest that Ag-NS offer a better analytical response compared to Ag-NPr, with a detection and quantification limit of 0.6 and 1.9 µg L-1, respectively. The proposed methodology was validated using a spiked tap water sample with a very high reproducibility and good agreement with inductively coupled plasma - mass spectrometry (ICP-MS) measurements.

Design of Stripping Columns Applied to Drinking Water to Minimize Carcinogenic Risk from Trihalomethanes (THMs).

The aim of this study is the application of a software tool to the design of stripping columns to calculate the removal of trihalomethanes (THMs) from drinking water. The tool also allows calculating the rough capital cost of the column and the decrease in carcinogenic risk indeces associated with the elimination of THMs and, thus, the investment to save a human life. The design of stripping columns includes the determination, among other factors, of the height (HOG), the theoretical number of plates (NOG), and the section (S) of the columns based on the study of pressure drop. These results have been compared with THM stripping literature values, showing that simulation is sufficiently conservative. Three case studies were chosen to apply the developed software. The first case study was representative of small-scale application to a community in Córdoba (Spain) where chloroform is predominant and has a low concentration. The second case study was of an intermediate scale in a region in Venezuela, and the third case study was representative of large-scale treatment of water in the Barcelona metropolitan region (Spain). Results showed that case studies with larger scale and higher initial risk offer the best capital investment to decrease the risk.

Assessment of the water chemical quality improvement based on human health risk indexes: Application to a drinking water treatment plant incorporating membrane technologies.

A methodology has been developed in order to evaluate the potential risk of drinking water for the health of the consumers. The methodology used for the assessment considered systemic and carcinogenic effects caused by oral ingestion of water based on the reference data developed by the World Health Organisation (WHO) and the Risk Assessment Information System (RAIS) for chemical contaminants. The exposure includes a hypothetical dose received by drinking this water according to the analysed contaminants. An assessment of the chemical quality improvement of produced water in the Drinking Water Treatment Plant (DWTP) after integration of membrane technologies was performed. Series of concentration values covering up to 261 chemical parameters over 5 years (2008-2012) of raw and treated water in the Sant Joan Despí DWTP, at the lower part of the Llobregat River basin (NE Spain), were used. After the application of the methodology, the resulting global indexes were located below the thresholds except for carcinogenic risk in the output of DWTP, where the index was slightly above the threshold during 2008 and 2009 before the upgrade of the treatment works including membrane technologies was executed. The annual evolution of global indexes showed a reduction in the global values for all situations: HQ systemic index based on RAIS dropped from 0.64 to 0.42 for surface water and from 0.61 to 0.31 for drinking water; the R carcinogenic index based on RAIS was negligible for input water and varied between 4.2×10(-05) and 7.4×10(-06) for drinking water; the W systemic index based on the WHO data varied between 0.41 and 0.16 for surface water and between 0.61 and 0.31 for drinking water. A specific analysis for the indexes associated with trihalomethanes (THMs) showed the same pattern.

Ecological screening indicators of stress and risk for the Llobregat river water.

The objective of this article is to develop and apply several simple and rough indicators for river aquatic ecosystems assessment in order to screen potential chemical stressors. Several indicators, based on toxicity (PNEC) and on legislation levels (EQS) have been developed. All these indicators are ratios that were calculated by using public and private data of concentrations of a large list of compounds during a period of five years, including metals and organic compounds in the lower part of the Llobregat river basin at the intake of the drinking water treatment plant. Additionally, new campaigns were executed for increasing the information available on the presence of compounds not routinely analyzed, such as some other pesticides and pharmaceuticals. In the case of inorganic pollutants, the indicators obtained in this river section showed significant risk especially for zinc, but also for copper, nickel and barium. For organic pollutants, the pesticides terbuthylazine, diazinon, 2-methyl-4-chlorophenoxyacetic (MCPA), and in a few cases, chlorpyrifos and lindane, also showed indexes above the threshold. Among the pharmaceuticals, the antibiotics clarithromycin and ciprofloxacin were the only ones with risk indicators adverse to ecosystems. The specific values of the indexes obtained rely on the quantity and quality of the data available, so their interpretation should take into account that some values can be high due to the use of too conservative toxicological information.

Comparación de la tasa de reestenosis entre stents convencionales y stents farmacoactivos en la enfermedad vascular del injerto / Comparison of restenosis rate of bare-metal and drug-eluting stents in cardiac allograft vasculopathy

Fundamento y objetivo: Evaluar si existen diferencias en la tasa de reestenosis entre stents convencionales (SC) y stents farmacoactivos (SFA) implantados para el tratamiento de la enfermedad vascular del injerto (EVI).Pacientes y método: Estudio retrospectivo que describe las características basales, evolución clínica y angiográfica de una muestra de pacientes con trasplante cardíaco y EVI sometidos a implantación de stents coronarios. Resultados: Se analizó el seguimiento de 40 stents (17 SC y 23 SFA), siendo este de media (DE) de 28 (18) meses (extremos 12 a 84). El grupo SFA presentaba menor tasa de tabaquismo activo, mayor porcentaje de estenosis residual y mayor uso de inhibidores de la enzima conversora de la angiotensina/antagonistas del receptor de la angiotensina de tipo II. Se realizó control angiográfico de 33 stents (82%). En el grupo SC (n=15) se identificaron 8 reestenosis (53%) y 2 (11%) en el grupo SFA (n=18) (p=0,02). Conclusión: En esta serie se observa menor tasa de reestenosis en el grupo de SFA, atribuible al efecto del fármaco liberado localmente por el stent (AU)

Background and objective: To assess whether there are differences in the rate of restenosis between bare metal stents (BMS) and drug eluting stents (DES) implanted for the treatment of cardiac allograft vasculopathy (CAV). Patients and methods: This retrospective study describes the baseline characteristics, clinical and angiographic evolution of a sample of heart transplant patients treated with coronary stent implantation due to CAV. Results: We analyzed the follow-up of 40 stents (17 BMS and 23 DES). Mean follow-up was 28±18 months (range 12 to 84). The DES group had a lower rate of active smoking, a higher percentage of residual stenosis and an increased use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers. Control angiography was performed in 33 stents (82%). In the BMS group (n=15), 8 restenosis were identified (53%) whereas 2 (11%) were seen in the DES group (n=18) (P=.02). Conclusion: In this series a lower rate of restenosis was observed in the DES group, attributable to the effect of the drug released locally by the stent (AU)

[Comparison of restenosis rate of bare-metal and drug-eluting stents in cardiac allograft vasculopathy]. / Comparación de la tasa de reestenosis entre stents convencionales y stents farmacoactivos en la enfermedad vascular del injerto.

BACKGROUND AND OBJECTIVE: To assess whether there are differences in the rate of restenosis between bare metal stents (BMS) and drug eluting stents (DES) implanted for the treatment of cardiac allograft vasculopathy (CAV). PATIENTS AND METHODS: This retrospective study describes the baseline characteristics, clinical and angiographic evolution of a sample of heart transplant patients treated with coronary stent implantation due to CAV. RESULTS: We analyzed the follow-up of 40 stents (17 BMS and 23 DES). Mean follow-up was 28 ± 18 months (range 12 to 84). The DES group had a lower rate of active smoking, a higher percentage of residual stenosis and an increased use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers. Control angiography was performed in 33 stents (82%). In the BMS group (n=15), 8 restenosis were identified (53%) whereas 2 (11%) were seen in the DES group (n=18) (P=.02). CONCLUSION: In this series a lower rate of restenosis was observed in the DES group, attributable to the effect of the drug released locally by the stent.