Spatial Distribution of Atmospheric PCBs in Zurich, Switzerland: Do Joint Sealants Still Matter?

Passive air samplers were deployed at 23 sites across the city of Zurich, Switzerland to investigate the spatial distribution of polychlorinated biphenyls (PCBs) in air. Concentrations of the six indicator PCBs (iPCBs) in air ranged from 54 to 3160 pg·m^–3 in the two sampling campaigns (spring 2011 and spring 2013). Measurements at two sampling sites were significantly higher than the median in both years, because of the proximity to primary PCB sources. Concentrations at most other stations were in a narrow range, suggesting that atmospheric PCB concentrations in Zurich are mainly caused by a high number of rather small sources. A correlation of iPCB concentrations in air with the number of buildings constructed between 1955 and 1975 in the surrounding areas of the sampling sites was observed. This demonstrates that PCB-containing building materials, such as joint sealants, influence PCB levels in urban air. Additionally, atmospheric iPCB concentrations were measured in the surrounding of a housing complex with PCB-contaminated joint sealants. Using a Gaussian diffusion model, annual iPCB emissions of 110−190 g were calculated for this housing complex. This appreciable amount released by a single building points out that more efforts are required to further eliminate remaining PCB stocks

A review of the environmental fate and effects of hazardous substances released from electrical and electronic equipments during recycling: examples from China and India

With the increasing global legal and illegal trade of waste electrical and electronic equipment (WEEE) comes an equally increasing concern that poor WEEE recycling techniques, particularly in developing countries, are generating more and more environmental pollution that affects both ecosystems and the people living within or near the main recycling areas. This review presents data found in the scientific and grey literature about concentrations of lead (Pb), polybrominated diphenylethers (PBDEs), polychlorinated dioxins and furans as well as polybrominated dioxins and furans (PCDD/Fs and PBDD/Fs) monitored in various environmental compartments in China and India, two countries where informal WEEE recycling plays an important economic role. The data are compared with known concentration thresholds and other pollution level standards to provide an indication of the seriousness of the pollution levels in the study sites selected and further to indicate the potential negative impact of these pollutants on the ecosystems and humans affected. The review highlights very high levels of Pb, PBDEs, PCDD/Fs and PBDD/Fs in air, bottom ash, dust, soil, water and sediments in WEEE recycling areas of the two countries. The concentration levels found sometimes exceed the reference values for the sites under investigation and pollution observed in other industrial or urban areas by several orders of magnitude. These observations suggest a serious environmental and human health threat, which is backed up by other studies that have examined the impact of concentrations of these compounds in humans and other organisms. The risk to the population treating WEEE and to the surrounding environment increases with the lack of health and safety guidelines and improper recycling techniques such as dumping, dismantling, inappropriate shredding, burning and acid leaching. At a regional scale, the influence of pollutants generated by WEEE recycling sites is important due to the long-distance transport potential of some chemicals. Although the data presented are alarming, the situation could be improved relatively rapidly by the implementation of more benign recycling techniques and the development and enforcement of WEEE-related legislation at the national level, including prevention of unregulated WEEE exports from industrialised countries

Studying the fate of non-volatile organic compounds in a commercial plasma air purifier

Degradation of non-volatile organic compounds-environmental toxins (methyltriclosane and phenanthrene), bovine serum albumin, as well as bioparticles (Legionella pneumophila, Bacillus subtilis, and Bacillus anthracis)-in a commercially available plasma air purifier based on a cold plasma was studied in detail, focusing on its efficiency and on the resulting degradation products. This system is capable of handling air flow velocities of up to 3.0m s(-1) (3200Lmin(-1)), much higher than other plasma-based reactors described in the literature, which generally are limited to air flow rates below 10Lmin(-1). Mass balance studies consistently indicated a reduction in concentration of the compounds/particles after passage through the plasma air purifier, 31% for phenanthrene, 17% for methyltriclosane, and 80% for bovine serum albumin. L. pneumophila did not survive passage through the plasma air purifier, and cell counts of aerosolized spores of B. subtilis and B. anthracis were reduced by 26- and 15-fold, depending on whether it was run at 10Hz or 50Hz, respectively. However rather than chemical degradation, deposition on the inner surfaces of the plasma air purifier occured. Our interpretation is that putative "degradation" efficiencies were largely due to electrostatic precipitation rather than to decomposition into smaller molecules

Short-Chain Chlorinated Paraffins in Zurich, SwitzerlandAtmospheric Concentrations and Emissions

Short-chain chlorinated paraffins (SCCPs) are of concern due to their potential for adverse health effects, bioaccumulation, persistence, and long-range transport. Data on concentrations of SCCPs in urban areas and underlying emissions are still scarce. In this study, we investigated the levels and spatial distribution of SCCPs in air, based on two separate, spatially resolved sampling campaigns in the city of Zurich, Switzerland. SCCP concentrations in air ranged from 1.8 to 17 ng·m^–3 (spring 2011) and 1.1 to 42 ng·m^–3 (spring 2013) with medians of 4.3 and 2.7 ng·m^–3, respectively. Both data sets show that atmospheric SCCP levels in Zurich can vary substantially and may be influenced by a number of localized sources within this urban area. Additionally, continuous measurements of atmospheric concentrations performed at one representative sampling site in the city center from 2011 to 2013 showed strong seasonal variations with high SCCP concentrations in summer and lower levels in winter. A long-term dynamic multimedia environmental fate model was parametrized to simulate the seasonal trends of SCCP concentrations in air and to back-calculate urban emissions. Resulting annual SCCP emissions in the city of Zurich accounted for 218–321 kg, which indicates that large SCCP stocks are present in urban areas of industrialized countries

Emissions of Polychlorinated Biphenyls in Switzerland: A Combination of Long-Term Measurements and Modeling

Ambient air concentrations of polychlorinated biphenyls (PCBs) in Zurich, Switzerland, are reported for the years 2011–2013. These measurements reveal a distinct seasonal trend with PCB concentrations in air during the summer that were three to five times higher than in the winter. We used a long-term dynamic multimedia model to analyze the seasonal trend and to back-calculate urban emissions of PCBs. In contrast to previous short-term studies that considered time periods of several days to months to extrapolate annual emissions, the use of long-term field data and the corresponding model reduces the uncertainty in these extrapolations. Comparison with measured PCB concentrations in air shows that our model is able to reproduce seasonal trends of the six indicator PCBs (iPCBs). The good agreement of the model results with measurements over a time period of three years provides confidence in model outputs and allows us to estimate the total annual PCB emissions of Zurich (86 μg capita^–1 d^–1). The resulting summer emissions are nine times higher than emissions during winter. Interestingly, this factor corresponds to the expected increase in PCB volatilization due to the effect of temperature on vapor pressure. This finding implies that PCBs in Zurich are probably released mainly by volatilization from sources that are directly exposed to ambient air temperature (i.e., outdoor sources). The derived emissions are in accordance with previous studies performed at the same location and are also in agreement with an existing emission inventory

Emissions of Polychlorinated Biphenyls, Polychlorinated Dibenzo‑<i>p</i>‑dioxins, and Polychlorinated Dibenzofurans during 2010 and 2011 in Zurich, Switzerland

Persistent organic pollutants (POPs) are ubiquitous contaminants of environmental and human health relevance, but their emissions into the environment are still poorly known. In this study, concentrations of selected POPs were measured in ambient air in Zurich, Switzerland, and interpreted with a multimedia mass balance model. The aim of the combination of measurements and modeling was to back-calculate atmospheric emission rates of POPs. Measurements were performed in summer 2010 and winter 2011 and target analytes included polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-<i>p</i>-dioxins and dibenzofurans (PCDD/Fs). Estimated emissions were higher in summer than in winter. Emission estimates for Zurich can be extrapolated to annual averages for Switzerland of 312 kg·a^–1 (39 mg·capita^–1·a^–1), 53 kg·a^–1 (7 mg·capita^–1·a^–1), and 3 kg·a^–1 (0.4 mg·capita^–1·a^–1, 94 g WHO98-TEQ·a^–1, 65 g I-TEQ·a^–1) for the six indicator PCBs (iPCBs), the twelve coplanar dioxin-like PCBs (dlPCBs), and the 17 2,3,7,8-chlorosubstituted PCDD/Fs, respectively. The emission rates of iPCBs are in agreement with existing emission inventories, whereas for PCDD/Fs the emissions are five times higher than the estimates from the Swiss national emission inventory. Emissions of dlPCBs in Switzerland are presented here for the first time. Our study also provides the first seasonally resolved emission rates of POPs, which were determined with our combined measurement and modeling approach. These findings highlight the relevance of ongoing sources of POPs, even decades after regulations aiming to reduce or eliminate sources were established

Autotransplant with and without induction chemotherapy in older multiple myeloma patients: long-term outcome of a randomized trial

Autologous transplantation is controversial for older patients with multiple myeloma. The role of age-adjusted high-dose melphalan and the impact of induction chemotherapy cycles is still unclear. A total of 434 patients aged 60-70 years were randomly assigned to 4 cycles of standard anthracycline-based induction chemotherapy or no induction. For all patients, double autologous transplantation after melphalan 140 mg/m(2) (MEL140) was planned. The primary end point was progression-free survival. Of 420 eligible patients, 85% received a first transplant and 69% completed double transplantation. Treatment duration was short with a median of 7.7 months with induction chemotherapy cycles and 4.6 months without induction. On an intention-to-treat basis, median progression-free survival with induction chemotherapy cycles (207 patients) was 21.4 months versus 20.0 months with no induction cycles (213 patients) (hazard ratio 1.04, 95% confidence interval 0.84-1.28; P= 0.36). Per protocol, progression-free survival was 23.7 months versus 23.0 months (P= 0.28). Patients aged 65 years or over (55%) did not have an inferior outcome. Patients with low-risk cytogenetics [absence of del17p13, t(4; 14) and 1q21 gains] showed a favorable overall survival and included the patients with sustained first remission. MEL140 was associated with a low rate of severe mucositis (10%) and treatment-related deaths (1%). Based on hazard ratio, the short treatment arm consisting of mobilization chemotherapy and tandem MEL140 achieved 96% of the progression-free survival, demonstrating its value as an independent component of therapy in older patients with multiple myeloma who are considered fit for autologous transplantation

Machine learning using the extreme gradient boosting (XGBoost) algorithm predicts 5-day delta of SOFA score at ICU admission in COVID-19 patients

Background: Accurate risk stratification of critically ill patients with coronavirus disease 2019 (COVID-19) is essential for optimizing resource allocation, delivering targeted interventions, and maximizing patient survival probability. Machine learning (ML) techniques are attracting increased interest for the development of prediction models as they excel in the analysis of complex signals in data-rich environments such as critical care. Methods: We retrieved data on patients with COVID-19 admitted to an intensive care unit (ICU) between March and October 2020 from the RIsk Stratification in COVID-19 patients in the Intensive Care Unit (RISC-19-ICU) registry. We applied the Extreme Gradient Boosting (XGBoost) algorithm to the data to predict as a binary out- come the increase or decrease in patients’ Sequential Organ Failure Assessment (SOFA) score on day 5 after ICU admission. The model was iteratively cross-validated in different subsets of the study cohort. Results: The final study population consisted of 675 patients. The XGBoost model correctly predicted a decrease in SOFA score in 320/385 (83%) critically ill COVID-19 patients, and an increase in the score in 210/290 (72%) patients. The area under the mean receiver operating characteristic curve for XGBoost was significantly higher than that for the logistic regression model (0.86 vs . 0.69, P < 0.01 [paired t -test with 95% confidence interval]). Conclusions: The XGBoost model predicted the change in SOFA score in critically ill COVID-19 patients admitted to the ICU and can guide clinical decision support systems (CDSSs) aimed at optimizing available resources