Konrad Hungerbühler

Assessment of the environmental persistence and long-range transport of endosulfan

Concentrations of the insecticide endosulfan (α- and β-isomer) and its degradation product endosulfan sulfate in air, seawater and soil are calculated with the global environmental fate model CliMoChem. As model input, physicochemical properties of all three compounds were assembled and a latitudinally and temporally resolved emission inventory was generated. For concentrations in air, model and measurements are in good agreement; a bimodal seasonality with two peaks in spring and fall as it is observed in Arctic air is reproduced by the model. For seawater, the agreement of model and measurements depends on the values of the hydrolysis activation energy of endosulfan used in the model; with relatively high values around 100 kJ/mol, model results match field data well. The results of this assessment of the levels, persistence, and global distribution of endosulfan are also relevant for the evaluation of endosulfan as a Persistent Organic Pollutant under the Stockholm Convention.

What determines PCB concentrations in soils in rural and urban areas? Insights from a multi-media fate model for Switzerland as a case study

Polychlorinated biphenyls (PCBs) are banned worldwide under the Stockholm Convention on Persistent Organic Pollutants. However, PCBs are still emitted in appreciable amounts from remaining primary sources in urban areas or landfills and are ubiquitous environmental contaminants, inter alia in soil and air. Concentrations of PCBs have been measured in various media by numerous studies worldwide. However, monitoring data do not always provide quantitative information about transport processes between different media, deposition fluxes to ground, or distribution of PCBs between environmental compartments. Also future trends in environmental contamination by PCBs cannot be predicted from monitoring data, but such information is highly relevant for decision-makers. Here, we present a new regionally resolved dynamic multimedia mass balance model for Switzerland to investigate the origin of PCBs in air and to investigate their long-term fate and mass balance in the environment. The model was validated with existing field data for PCBs. We find that advective inflow of PCBs from outside Switzerland into the atmospheric boundary layer is responsible for 80% of PCBs present in air in Switzerland, whereas Swiss emissions cause the remaining 20%. Furthermore, we show that the atmospheric deposition of the higher-chlorinated PCBs is dominated by particle-bound deposition, whereas the deposition of the lower-chlorinated PCBs is a combination of particle-bound and gaseous deposition. The volume fraction of particles in air is in both cases an important factor driving the deposition of PCBs to ground and, thus, contributing to the higher concentrations of PCBs generally observed in populated and polluted areas. Regional emissions influence the deposition fluxes only to a limited extent. We also find that secondary emissions from environmental reservoirs do not exceed primary emissions for all PCB congeners until at least 2036. Finally, we use our model to evaluate the effect of chemical regulation on future environmental contamination by PCBs.

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.

Occurrence and mass balance of isoflavones on an experimental grassland field.

Isoflavones and coumestrol (COU) are estrogenic compounds that are naturally produced by plants (e.g., red clover, soybeans). Although these compounds have been extensively studied in food and feed, only little is known about their environmental fate. Therefore, we investigated the occurrence of isoflavones (formononetin, daidzein, equol, biochanin A, and genistein) and COU over 3.5 years in red clover, manure, and soil of a grassland field with and without manure application, as well as their emission via drainage water. Isoflavones were regularly quantified in plant (≤ 15 × 10(6) ng/g(dry weight (dw))), manure (≤ 230 × 10(3) ng/g(dw)), soil (≤ 3.4 × 10(3) ng/g(dw)), and drainage water samples (≤ 3.6 × 10(3) ng/L). In contrast, COU was observed only in manure and soil. Cumulative isoflavone loads emitted via drainage water were around 0.2 × 10(-3) kg/ha/y, which is very little compared to the amounts present in red clover (105-220 kg/ha/y), manure (0.5-1.0 kg/ha/y), and soil (0.1-5.1 kg/ha/y). Under good agricultural practice, no additional emission of isoflavones into drainage water was observed after manure application. With calculated 17β-estradiol equivalents up to 0.46 ng/L in drainage water, isoflavones can constitute a dominant and ecotoxicological relevant portion of the total estrogenicity in small rural river catchments.

Investigating the use of path flow indicators as optimization drivers in batch process retrofitting

Abstract Improvement of batch processes has gained much attention in industry due to the competitive market and stricter environmental legislation. This paper focuses on a process flowsheet decomposition based methodology resulting in path flow indicators which are able to highlight process alternatives with an improved performance. The novel aspects introduced in this methodology are the implementation of a new path flow indicator category that focuses on unit occupancy time and the multi-objective process assessment in order to reveal sustainable retrofitting actions. Furthermore, the retrofit alternatives are not only classified according to the diverse objective functions but also to the differences observed in the path flow indicator matrix of the generated retrofit alternatives compared to the base case. This classification enables a more detailed analysis of the retrofit alternative impact and illustrates the potential of path flow indicators as optimization drivers. The methodology is exemplified in an industrial batch process case study.

Use-patterns of personal care and household cleaning products in Switzerland.

Reliable consumer use data are needed to determine health risks posed by chemicals contained in household cleaning and personal care products. Essential information includes the amount of product applied, the frequency of use, and the site of application. To obtain such data, a survey was conducted in Switzerland to assess consumer usage patterns. The use-patterns of 12 household care products, 5 laundry products, and 22 personal care products were collected among the Swiss population (Nxa0=xa0759; ages 0-91) by postal questionnaire, providing for the first time in Europe comprehensive information regarding use of household cleaning and personal care products for the same study population. Apart from the investigation of use frequency, quantity, duration, and habits, also co-use analysis was performed separately for household and personal care products. Use-patterns are presented for both genders and all age groups, including children below the age of 12, who may be more vulnerable to adverse effects attributed to certain chemicals. Also, the currently missing use factors for cosmetic/baby wet wipes were assessed. Stratification of the data by gender, age and other socio-demographic factors, such as region affiliation, allowed us to identify differences between population sub-groups, emphasizing the need for region-specific exposure factors.

Local organochlorine pesticide concentrations in soil put into a global perspective

In this work, agricultural and background soil concentrations of p,p-DDT, p,p-DDE, HCB, α-, β- and γ-HCH from 1993 to 2012 were collected from 73 peer-reviewed publications, and analysed statistically. For the period 2003-2012 and for all chemicals, the mean concentration in agricultural soil is significantly higher than the concentration in background soil. In addition to the statistical analysis, concentrations of p,p-DDT and α-HCH in soils were calculated with a global environmental fate and transport model. A decrease in the mean soil concentration from the first decade to the second was observed with the model, but this decrease is not visible in the measured concentrations, which could result from ongoing use of p,p-DDT and α-HCH Furthermore, modelled background soil concentrations are generally lower than measurements. This implies that background soil may have received p,p-DDT and α-HCH through additional routes not described by the model such as spray drift.

Data-driven tiered procedure for enhancing yield in drug product manufacturing

Enhancing efficiency of pharmaceutical batch production processes is an important challenge in times of increasing public pressure on healthcare costs and decreasing research productivity. This study presents a data-based procedure for systematic yield enhancements in drug product manufacturing, based on four steps. On the first step, production is reviewed to select relevant loss causes, which are assessed on the second step deductively with the goal of assigning measurable parameters. Descriptive Statistical Modelling of loss causes is then performed on the third step, enabling model-based enhancements of processes on the fourth step or, if necessary, a loop-back review of a given loss cause. An industrial case study was performed on production data of 88 batches and demonstrated the applicability of the procedure by prioritizing relevant loss causes, reducing required sample quantities by up to 8% and a cosmetic defect by about 70% by a process change.

Rigorous approach to scheduling of sterile drug product manufacturing

Abstract Optimizing the scheduling of liquid drug product manufacturing is paramount for pharmaceutical companies in their increasingly competitive environment and requires the modelling of industry-specific constraints. Such constraints include: (i) changing sequence-dependent setup times; (ii) maintaining a sterile production environment (e.g., through sterile holding times); (iii) periods with limited or no plant activity (e.g., no workforce during weekends); and (iv) demand timing (i.e., delivery deadline and release date constraints). In this work, an immediate precedence model is formulated to optimize the scheduling of liquid drug product manufacturing, considering the industry-specific constraints. The primary objective is to minimize the production makespan. Four case studies comprising up to 38 batches from a real multi-product facility illustrate the performance of the rigorous optimization approach. The makespan could be reduced by up to 7.9% compared to expert schedules.

Mathematical Optimization of Real-time Waste Incineration Scheduling in the Industry

Abstract This work proposes a novel approach for handling transfer activities together with storage and processing tasks in the field of waste incineration. Given a set of waste streams, a detailed plant topology, short or medium-term strategy specifications, and optimization targets, the developed model optimizes the schedule for the incineration of liquid waste along a given time horizon, from a waste transfer but also economic and sustainable point of view. Additionally, detailed waste transfer, storage, mixing and incineration assignments along with their start and processing time are provided. Tests in industry show that the obtained optimized schedules can efficiently support real-time decisions, leading to a more cost efficient and sustainable waste incineration.