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Rare Earth Elements (REEs) are used in increasing amounts in technical applications and consumer products. However, to date, the contribution of industrial sources to the loads of individual REEs in wastewater streams have not been quantified. Here, we determine the REE contents in sludge collected from 63 wastewater treatment plants (WWTPs) across Switzerland. To quantify the industrial fraction of individual REEs in the sewage sludge, we develop two complementary approaches, based on REE ratios and REE pattern fitting. Unspecific (background) inputs, with REE patterns similar to the averaged REE pattern of soils collected across Switzerland, dominate the REE budget of most WWTPs. A few WWTPs receive significant REE inputs from specific industrial sources. Based on population equivalents of Switzerland, we estimate a total annual load of 4200 kg Cerium (Ce, 0.5 g Ce year-1 capita-1), with an industrial contribution of 2000 kg year-1. The latter agrees with estimates of probabilistic mass flow models for engineered nanoscale CeO2 particles discharged to the sewer network. About 7 kg year-1 of Samarium (Sm,total for Switzerland: 184 kg year-1 or 0.02 g Sm year-1 capita-1) and 3 kg year-1 of Europium (Eu,total for Switzerland: 44 kg year-1 or 0.005 g Eu year-1 capita-1) are assigned to industrial inputs from single WWTPs. Gadolinium (Gd) is used in the form of a stable complex as contrast agent in magnetic resonance imaging. Assuming 10% removal of Gd during wastewater treatment, we calculate an annual discharge of 90 kg of Gd from one individual WWTP to surface waters. WWTPs with exceptionally high industrial inputs of specific REEs warrant detailed investigations to identify the respective sources and to assess whether REE concentrations in effluents are elevated to the same degree., Water Research X, 11, ISSN:2589-9147

Mercury (Hg) pollution threatens ecosystems and human health. Wastewater treatment plants (WWTPs) play a key role in limiting Hg discharges from wastewaters to rivers and lakes, but large-scale studies to estimate Hg loads and discharge at national levels are scarce. We assessed the concentration, flux, speciation, and removal of Hg in municipal wastewater throughout Switzerland by investigating 64 WWTPs in a pre-study and a subset of 28 WWTPs in the main study. We also studied the behavior and pathways of Hg along the various treatment steps in a state-of-the-art WWTP. The resulting dataset, representative of industrialized countries, provides an overview of (i) current Hg concentration ranges, (ii) average per capita loads, and (iii) wastewater Hg inputs into surface waters. The results allowed estimation of a total Hg (THg) load in Swiss wastewater of 130 ± 30 kg THg/year (15.7 mg/capita/y), of which 96 ± 4% is retained in sewage sludge. About 4.7 ± 0.5 kg THg/year (0.57 mg/capita/y) is discharged with the treated wastewater into surface waters. This corresponds to only 1.5–3% of the THg load carried by the major Swiss rivers, indicating that >95% of riverine Hg originates from other sources. Extrapolation to the population of Europe would yield a total amount of 11,700 kg THg/year in raw wastewater, with some 480 kg THg/year discharged to surface waters. Monomethyl mercury on average accounted for 0.23% of THg, and its fraction remained constant along the different treatment steps. ISSN:0043-1354 ISSN:1879-2448

The number and quantities of trace elements used in industry, (high-tech) consumer products, and medicine are rapidly increasing, but the resulting emissions and waste streams are largely unknown. We assessed the concentrations of 69 elements in digested sewage sludge and effluent samples from 64 municipal wastewater treatment plants as well as in major rivers in Switzerland. This data set, representative of an entire industrialized country, presents a reference point for current element concentrations, average per-capita fluxes, loads discharged to surface waters, and economic waste-stream values. The spatial distribution of many individual elements could be attributed either to predominant geogenic or to anthropogenic inputs. Per-capita element fluxes ranged from 1 mg day–1 (e.g., Zn, Sc, Y, Nb, and Gd) and >1 g day–1 (e.g., for P, Fe, and S). Effluent loads of some elements contributed significantly to riverine budgets (e.g., 24% for Zn, 50% for P, and 83% for Gd...

Per- and polyfluoroalkyl substances (PFASs) are man-made chemicals that contain at least one perfluoroalkyl moiety, [Formula: see text]. To date, over 4,000 unique PFASs have been used in technical applications and consumer products, and some of them have been detected globally in human and wildlife biomonitoring studies. Because of their extraordinary persistence, human and environmental exposure to PFASs will be a long-term source of concern. Some PFASs such as perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) have been investigated extensively and thus regulated, but for many other PFASs, knowledge about their current uses and hazards is still very limited or missing entirely. To address this problem and prepare an action plan for the assessment and management of PFASs in the coming years, a group of more than 50 international scientists and regulators held a two-day workshop in November, 2017. The group identified both the respective needs of and common goals shared by the scientific and the policy communities, made recommendations for cooperative actions, and outlined how the science-policy interface regarding PFASs can be strengthened using new approaches for assessing and managing highly persistent chemicals such as PFASs. https://doi.org/10.1289/EHP4158.

The time-dependent stock of PBDEs contained in in-use products (excluding building materials and large vehicles) was estimated for the U.S. and Canada from 1970 to 2020 based on product consumption patterns, PBDE contents, and product lifespan. The stocks of penta- and octaBDE peaked in in-use products at 17,000 (95% confidence interval: 6000-70,000) and 4,000 (1,000-50,000) tonnes in 2004, respectively, and for decaBDE at 140,000 (40,000-300,000) tonnes in 2008. Products dominating PBDE usage were polyurethane foam used in furniture (65% of pentaBDE), casings of electrical and electronic equipment or EEE (80% of octaBDE), and EEE and automotive seating (35% of decaBDE for each category). The largest flow of PBDEs in products, excluding automotive sector, to the waste phase occurred between 2005 and 2008 at ∼10,000 tonnes per year. Total consumption of penta-, octa-, and decaBDE from 1970 to 2020 in products considered was estimated at ∼46,000, ∼25,000, and ∼380,000 tonnes, respectively. Per capita usage was estimated at 10-250, 10-150, and 200-2000 g·capita(-1)·y(-1) for penta-, octa-, and decaBDE, respectively, over the time span. Considering only the first use (no reuse and/or storage) of PBDE-containing products, approximately 60% of the stock of PBDEs in 2014 or ∼70,000 tonnes, of which 95% is decaBDE, will remain in the use phase in 2020. Total emissions to air of all PBDEs from the in-use product stock was estimated at 70-700 tonnes between 1970 and 2020, with annual emissions of 0.4-4 tonnes·y(-1) for each of penta- and octaBDE and 0.35-3.5 tonnes·y(-1) for decaBDE in 2014.

Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants but they are of concern and are currently being phased-out because of their environmentally hazardous properties and their potential to cause adverse health effects. We analyzed PBDEs in Zurich, Switzerland, and applied a multi-media environmental fate model to back-calculate the rate of PBDE emission to air. PBDE concentrations in ambient air were measured in summer 2010 and winter 2011 in the city center of Zurich. Concentrations were higher in summer (sum PBDEs 118-591 pg m(-3)) than in winter (sum PBDEs 17-151 pg m(-3)), and are on the upper end of concentrations reported in literature for urban sites with no point sources of PBDEs. The emissions derived from our measurements (summer: 53-165 μg capita(-1) d(-1), winter: 25-112 μg capita(-1) d(-1)) and extrapolated to annual emissions for Switzerland (114-406 kg a(-1)) lie in the middle of ranges reported on the basis of substance flow analyses and emission inventories. The difference between summer and winter emissions is small compared to the difference that would be expected from the temperature dependence of PBDE vapor pressure, which would be consistent with emissions occurring to a large extent from flame-proofed materials located indoors under nearly constant temperature conditions and/or emissions to air occurring by suspension of particles containing PBDEs. Compared to previous studies in Switzerland, concentrations and emissions of PBDEs appear to have increased during the last five years with an increasing contribution of decabromodiphenyl ether, despite the addition of PBDEs to national and international regulations.

Multimedia mass balance models of chemical fate in the environment have been used for over 3 decades in a regulatory context to assist decision making. As these models become more comprehensive, reliable, and accepted, there is a need to recognize and adopt principles of Good Modeling Practice (GMP) to ensure that multimedia models are applied with transparency and adherence to accepted scientific principles. We propose and discuss 6 principles of GMP for applying existing multimedia models in a decision-making context, namely 1) specification of the goals of the model assessment, 2) specification of the model used, 3) specification of the input data, 4) specification of the output data, 5) conduct of a sensitivity and possibly also uncertainty analysis, and finally 6) specification of the limitations and limits of applicability of the analysis. These principles are justified and discussed with a view to enhancing the transparency and quality of model-based assessments.

Hintergrund, Ziel und Zweck Biozide wurden als Mikroverunreinigungen bisher weniger beachtet als beispielsweise Pestizide oder Arzneistoffe. Eine Studie zur Priorisierung der in der Schweiz eingesetzten Biozide bezuglich Gewasserbelastung ergab fur quartare Ammoniumverbindungen (QAV), die Isothiazolinone Chlormethylisothiazolinon und Benzisothiazolinon sowie Irgarol die grosten Gefahrdungspotentiale. Die QAV Benzalkoniumchlorid (BAC) und Didecyldimethylammoniumchlorid (DDAC-C10) werden in erheblichen Mengen eingesetzt und besitzen eine hohe biologische Aktivitat. Methoden In dieser Arbeit wurden mittels einer Stoffflussanalyse (SFA) fur die Schweiz die Eintrage von ausgewahlten QAV in Gewasser und in Boden modelliert und die zu erwartenden Umweltkonzentrationen abgeschatzt. Die Studie basierte auf den Eintragen im schweizerischen Produkteregister, auf Literaturdaten, Kontakten zu Herstellern und Anwendern sowie auf eigenen Annahmen. Ergebnisse und Diskussion In der Schweiz werden pro Jahr rund 90 t BAC (vier Homologen) und 30 t DDAC-C10 in bioziden Anwendungen eingesetzt. Die wichtigsten Anwendungen sind Flachendesinfektionsmittel, Desinfektionsmittel fur Lebens- und Futtermittel sowie Holzschutzmittel. Es wurde abgeschatzt, dass die jahrlichen Umweltemissionen aus bioziden Anwendungen aller funf Substanzen jahrlich rund 11 t betragen. Die PECs fur Oberflachenwasser und Sediment liegen zwischen knapp und drei Grosenordnungen unter dem PNEC (predicted no-effect concentration). In einigen Gewassern, insbesondere unterhalb von Klaranlageneinleitungen und der Regenwasserentlastung durften jedoch Konzentrationen oberhalb des PNEC moglich sein. Ein okotoxischer Einfluss auf aquatische Organismen kann daher nicht ausgeschlossen werden. Drei BAC-Homologen konnten nicht bewertet werden, da keine PNEC-Werte verfugbar waren. Schlussfolgerungen Von den Gesamtemissionen ist der aus Klaranlagen emittierte Anteil (punktformige Emissionen) heute mit rund einem Zehntel relativ bescheiden. Dies bedeutet, dass weitere Masnahmen zur Emissionsminderung, die nur in der Klaranlage mit End-of-Pipe-Losungen ansetzen, keine wesentliche Verbesserung der Emissionssituation mehr bringen. Zusatzlich muss bei der Beurteilung von Masnahmen beachtet werden, dass biozide Wirkstoffe wie die untersuchten QAV haufig auch in nicht-bioziden Anwendungen zum Einsatz kommen. Empfehlungen und Ausblick Mittels SFA konnen durch Chemikalien verursachte Umweltprobleme fruhzeitig erkannt und so zielfuhrende Masnahmen zur Belastungsreduktion in Produktion, Einsatz und Entsorgung vorgeschlagen werden. Es wird daher empfohlen, SFA schon in der Entwicklungsphase und spater zur allfalligen Erfolgskontrolle vermehrt anzuwenden. Damit konnen in komplexen Systemen auch ohne umfangreiche Messungen oder bei Abwesenheit eines stoffmengenbezogenen Chemikalienregisters anhand von Abschatzungen bzw. Szenarien die Quellen bestimmt werden, die fur das Auftreten von Substanzen in der Umwelt relevant sind.

Fur das Beispiel der bromierten Flammschutzmittel (BFS), einer Klasse von Substanzen, die sehr wertvolle Material-Eigenschaften besitzen, deren Vertreter aber als zukunftige POP-Substanzen gehandelt werden, wird die Bedeutung der Abfallwirtschaft und der Recycling-Prozesse aus Schadstoffsicht beleuchtet. Die Ausfuhrungen sollen dazu beitragen, dass neben dem Ressourcenmanagement (Wertstoffnutzung) auch ein Schadstoffmanagement erfolgt und mehr Wissen uber die Effizienz von Recycling-Prozessen und die Qualitat von Sekundarressourcen erarbeitet wird. Zusatzlich wird unterstrichen, dass Gesamtsystembetrachtungen zur Optimierung des Ressourcenmanagements und fur die Problemanalyse und Definition von Masnahmen zur Risikoreduktion unerlasslich sind. Dies ist wichtig, um den immer hoher werdenden Anforderungen bezuglich Qualitatsstandards an Produkte von KundInnen- und KonsumentInnenseite auch bezuglich Schadstoffgehalte gerecht zu werden. Nur so kann langfristig verhindert werden, dass Schadstoffe fur die Aufrechterhaltung von Material- oder Stoffkreislaufen im Ressourcenmanagement ein limitierender Faktor werden und langsam in die Umwelt emittieren. Statt ein potenzielles Langzeitproblem fur Mensch und Umwelt zu erzeugen, konnen Schadstoffe so in die geeigneten letzten Senken gelenkt werden.

The review article "Emergence and fate of cyclic volatile polydimethylsiloxanes (D4, D5) in municipal waste streams: Release mechanisms, partitioning and persistence in air, water, soil and sediments" by Surita and Tansel covers a relevant topic, but there are several serious issues with this paper. The inappropriate handling of data gathered from various sources has resulted in a flawed dataset. In addition, the authors performed several erroneous or meaningless calculations with the data. Their dataset leads to incorrect and misleading interpretations and should not be used.

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-p-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.

Tens of thousands of tonnes of cyclic volatile methylsiloxanes (cVMS) are used each year globally, which leads to high and continuous cVMS emissions to air. However, field measurements of cVMS in air and empirical information about emission rates to air are still limited. Here we present measurements of decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) in air for Zurich, Switzerland. The measurements were performed in January and February 2011 over a period of eight days and at two sites (city center and background) with a temporal resolution of 6-12 h. Concentrations of D5 and D6 are higher in the center of Zurich and range from 100 to 650 ng m(-3) and from 10 to 79 ng m(-3), respectively. These values are among the highest levels of D5 and D6 reported in the literature. In a second step, we used a multimedia environmental fate model parametrized for the region of Zurich to interpret the levels and time trends in the cVMS concentrations and to back-calculate the emission rates of D5 and D6 from the city of Zurich. The average emission rates obtained for D5 and D6 are 120 kg d(-1) and 14 kg d(-1), respectively, which corresponds to per-capita emissions of 310 mg capita(-1) d(-1) for D5 and 36 mg capita(-1) d(-1) for D6.

Siloxanes are used in high amounts in a wide range of applications. There is evidence that siloxanes may be persistent and bioaccumulative in the environment. Despite their high production volumes and their wide applications, only few empirical data on their physicochemical properties are available. For a selection of linear and cyclic siloxanes and siloxanols, we computed (subcooled) liquid vapor pressure, (subcooled) liquid water solubility, and the partition coefficients among air, water, and octanol with the property estimation methods, EPI Suite, SPARC, and COSMOtherm and compared the results to experimental data from the literature. The estimates obtained with the three methods generally show decent qualitative and limited quantitative agreement in the estimated trends of property data for the homologous series of linear and cyclic dimethylsiloxane oligomers. The number of measured property data available in the literature is small, but the data show considerable scatter, and their ranges exceed the differences among the three estimation methods in several cases. A strong impact of molecular configurations and conformations on substance properties could be demonstrated by means of COSMOtherm. In a case study we illustrate that these effects are large enough to greatly influence the environmental fate of the transformation products of octamethylcyclotetrasiloxane (D4).

Most studies of potentially hazardous substances focus on aspects of their occurrence and fate in the environment (monitoring and modelling studies) to estimate the environmental impact and the potential exposure of humans. In order to evaluate emission sources, to recognise environmental impacts at an early stage, and to take efficient legislative or technical measures, it is essential to know their behaviour in the anthroposphere as a function of time. So far, only very few investigations of this type exist for chemicals. In regular risk assessments, only rather limited knowledge is available concerning the behaviour of chemicals in the anthroposphere (production data, substance quantities in products, recycling rates, emissions occurring during use, etc.) or their lifecycle, and no information at all about their behaviour as a function of time. For this reason, it is these aspects that were investigated in a case study within the framework of the national research programme NRP50 for selected brominated flame retardants with endocrine-disrupting potential (pentabromodiphenyl ether, hexabromocyclododecane) or the potential to degrade to such substances (decabromodiphenyl ether). A dynamic substance flow analysis (SFA) model was performed for Switzerland for the time period 1980–2020. In this review paper (a) we present a summary of typical results (system overview, consumption trends/application patterns, anthropogenic stocks and their changes, emission trends including major sources and environmental fate), (b) we summarize the effectiveness of recent risk-reduction measures in Switzerland and (c) we indicate serious remaining data gaps and recommend further important measures for risk reduction. For the future, we suggest improving the knowledge of the lifecycle of chemicals such as brominated flame retardants by applying SFA as a suitable tool to weight the effect of substance flows with respect to environmental emissions, and to serve as the basis for planning actions and measures to reduce such emissions. This is in line with one major conclusion of the NRP50 consensus platform 'Brominated Flame Retardants'.

Short- and medium-chain chlorinated paraffins are potential PBT chemicals (persistent, bioaccumulative, toxic) and short-chain chlorinated paraffins are under review for inclusion in the UNEP Stockholm Convention on Persistent Organic Pollutants. Despite their high production volume of more than one million metric tonnes per year, only few data on their physicochemical properties are available. We calculated subcooled-liquid vapor pressure, subcooled-liquid solubility in water and octanol, Henry's law constant for water and octanol, as well as the octanol-water partition coefficient with the property calculation methods COSMOtherm, SPARC, and EPI Suite™, and compared the results to experimental data from the literature. For all properties, good or very good agreement between calculated and measured data was obtained for COSMOtherm; results from SPARC were in good agreement with the measured data except for subcooled-liquid water solubility, whereas EPI Suite™ showed the largest discrepancies for all properties. After critical evaluation of the three property calculation methods, a final set of recommended property data for short- and medium-chain chlorinated paraffins was derived. The calculated property data show interesting relationships with chlorine content and carbon chain length. Increasing chlorine content does not cause pronounced changes in water solubility and octanol-water partition coefficient (KOW) as long as it is below 55%. Increasing carbon chain length leads to strong increases in KOW and corresponding decreases in subcooled-liquid water solubility. The present data set can be used in further studies to assess the environmental fate and human exposure of this relevant compound class.

Ecological health of 15 sites in two mining areas on the West Coast of the South Island, New Zealand, was assessed using a non-invasive electrophysiological technique. The conduction velocity (CV) changes in the medial giant fibres (MGF) of the terrestrial earthworm Aporrectodea caliginosa were measured on days 0, 1, 2, 4, 7, 14, and 21 following exposure to soil and/or sediment from six acid mine drainage (AMD) sites, and aquatic oligochaete Lumbriculus variegatus at 0, 3, 6, and 24 h following exposure to water from 14 AMD sites. The colour of the soil/sediments varied from red-brown to black with pH ranging from 4.46 to 7.37. The colour of AMD water samples varied from clear, black, brown to orange, and the pH ranged from 2.99 to 7.66. The CV decreased progressively in A. caliginosa exposed to most soil and sediment samples from the AMD sites (compared with controls exposed to soil from an organic farm) and this was most evident in measurements taken at 7 days. Based on the CV measurements taken on day 7, sites 321 were significantly (P0.05) the most toxic to earthworms. The CV of L. variegatus exposed to AMD water sampled from many sites also decreased progressively and this was significantly lower than the controls in the measurements taken at 24 h from sites 39711. It is proposed that MGF CV in A. caliginosa and L. variegatus worms can be used as a non-invasive, sensitive, biomarker to monitor the toxicity of AMD sites.