Evaluating the reliability of environmental concentration data to characterize exposure in environmental risk assessments.

Environmental risk assessments often rely on measured concentrations in environmental matrices to characterize exposure of the population of interest-typically, humans, aquatic biota, or other wildlife. Yet, there is limited guidance available on how to report and evaluate exposure datasets for reliability and relevance, despite their importance to regulatory decision-making. This paper is the second of a four-paper series detailing the outcomes of a Society of Environmental Toxicology and Chemistry Technical Workshop that has developed Criteria for Reporting and Evaluating Exposure Datasets (CREED). It presents specific criteria to systematically evaluate the reliability of environmental exposure datasets. These criteria can help risk assessors understand and characterize uncertainties when existing data are used in various types of assessments and can serve as guidance on best practice for the reporting of data for data generators (to maximize utility of their datasets). Although most reliability criteria are universal, some practices may need to be evaluated considering the purpose of the assessment. Reliability refers to the inherent quality of the dataset and evaluation criteria address the identification of analytes, study sites, environmental matrices, sampling dates, sample collection methods, analytical method performance, data handling or aggregation, treatment of censored data, and generation of summary statistics. Each criterion is evaluated as "fully met," "partly met," "not met or inappropriate," "not reported," or "not applicable" for the dataset being reviewed. The evaluation concludes with a scheme for scoring the dataset as reliable with or without restrictions, not reliable, or not assignable, and is demonstrated with three case studies representing both organic and inorganic constituents, and different study designs and assessment purposes. Reliability evaluation can be used in conjunction with relevance evaluation (assessed separately) to determine the extent to which environmental monitoring datasets are "fit for purpose," that is, suitable for use in various types of assessments. Integr Environ Assess Manag 2024;20:981-1003. © 2024 Society of Environmental Toxicology & Chemistry (SETAC). This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

What is in the fish? Collaborative trial in suspect and non-target screening of organic micropollutants using LC- and GC-HRMS.

A collaborative trial involving 16 participants from nine European countries was conducted within the NORMAN network in efforts to harmonise suspect and non-target screening of environmental contaminants in whole fish samples of bream (Abramis brama). Participants were provided with freeze-dried, homogenised fish samples from a contaminated and a reference site, extracts (spiked and non-spiked) and reference sample preparation protocols for liquid chromatography (LC) and gas chromatography (GC) coupled to high resolution mass spectrometry (HRMS). Participants extracted fish samples using their in-house sample preparation method and/or the protocol provided. Participants correctly identified 9-69 % of spiked compounds using LC-HRMS and 20-60 % of spiked compounds using GC-HRMS. From the contaminated site, suspect screening with participants' own suspect lists led to putative identification of on average ∼145 and ∼20 unique features per participant using LC-HRMS and GC-HRMS, respectively, while non-target screening identified on average ∼42 and ∼56 unique features per participant using LC-HRMS and GC-HRMS, respectively. Within the same sub-group of sample preparation method, only a few features were identified by at least two participants in suspect screening (16 features using LC-HRMS, 0 features using GC-HRMS) and non-target screening (0 features using LC-HRMS, 2 features using GC-HRMS). The compounds identified had log octanol/water partition coefficient (KOW) values from -9.9 to 16 and mass-to-charge ratios (m/z) of 68 to 761 (LC-HRMS and GC-HRMS). A significant linear trend was found between log KOW and m/z for the GC-HRMS data. Overall, these findings indicate that differences in screening results are mainly due to the data analysis workflows used by different participants. Further work is needed to harmonise the results obtained when applying suspect and non-target screening approaches to environmental biota samples.

Tracking down unknown PFAS pollution - The direct TOP assay in spatial monitoring of surface waters in Germany.

PFAS contamination of surface waters in central Europe was investigated in a spatial monitoring using suspended particulate matter and sediment samples. The samples were collected in 2021 at 171 sampling sites in Germany and at five sites in Dutch waters. All samples were analyzed for 41 different PFAS by target analysis to establish a baseline for these compounds. In addition, a sum parameter approach (direct Total Oxidizable Precursor (dTOP) assay) was used to investigate the PFAS load in the samples more comprehensively. PFAS pollution varied widely between water bodies. Target analysis detected ∑PFAS concentrations between <0.5 and 53.1 µg kg-1 dry weight (dw), while levels of <1.0-337 µg kg-1 dw were determined by dTOP assay. Associations were observed for ∑PFSAdTOP and the percentage of urban area in the vicinity of the sampling sites and, less strongly, for distances to industrial sites (i.e. galvanic/paper) and airports. PFAS hotspots were identified by setting the 90th percentile of the data sets for ∑PFAStarget or ∑PFASdTOP as a threshold. Of the 17 hotspots identified by target analysis or dTOP assay, respectively, there were only six overlaps. Thus, 11 highly contaminated sites could not be identified by classical target analysis. The results demonstrate that target analysis captures only a fraction of the actual PFAS load, while unknown precursors remain undetected. Consequently, if only the results of target analysis are considered in assessments, there is a risk that sites heavily polluted with precursors will not be identified delaying mitigation actions and risking prolonged negative impacts on human health and ecosystems. Moreover, effective PFAS management requires establishing a baseline for PFAS using target and sum parameters such as the dTOP assay, and then monitoring this baseline on a regular basis to support emission control and to inform risk management of its effectiveness.

Quantification and characterization of PFASs in suspended particulate matter (SPM) of German rivers using EOF, dTOPA, (non-)target HRMS.

In this study, we compare analytical methods for PFAS determination-target analysis, non-target screening (NTS), direct total oxidizable precursor assay (dTOPA) and extractable organically bound fluorine (EOF). Therefore, suspended particulate matter (SPM) samples from German rivers at different locations in time series from 2005 to 2020 were analyzed to investigate temporal and spatially resolved trends. In this study 3 PFAS mass balances approaches were utilized: (i) PFAA target vs. PFAS dTOPA, (ii) PFAS target vs. EOF and (iii) PFAS target vs. PFAS dTOPA vs. organofluorines NTS vs. EOF. Mass balance approach (i) revealed high proportions of precursor substances in SPM samples. For the time resolved analysis an increase from 94% (2005) to 97% in 2019 was observable. Also for the spatial resolved analysis precursor proportions were high with >84% at all sampling sites. Mass balance approach (ii) showed that the unidentified EOF (uEOF) fraction increased over time from 82% (2005) to 99% (2019). Furthermore, along the river courses the uEOF increased. In the combined mass balance approach (iii) using 4 different analytical approaches EOF fractions were further unraveled. The EOF pattern was fully explainable at the sampling sites at Saar and Elbe rivers. For the time resolved analysis, an increased proportion of the EOF was now explainable. However, still 27% of the EOF for the time resolved analysis and 25% of the EOF for the spatial resolved analysis remained unknown. Therefore, in a complementary approach, both the EOF and dTOPA reveal unknown gaps in the PFAS mass balance and are valuable contributions to PFAS risk assessment. Further research is needed to identify organofluorines summarized in the EOF parameter.

Environmental specimen banks and the European Green Deal.

The study highlights the potential of Environmental Specimen Banks (ESBs) for implementing the Zero Pollution Ambition and the Biodiversity Strategy of the European Green Deal. By drawing on recent monitoring studies of European ESBs, we illustrate the role ESBs already play in assessing the state of ecosystems in Europe and how they help to make developments over time visible. The studies reveal the ubiquitous presence of per- and polyfluoroalkyl substances, halogenated flame retardants, chlorinated paraffins, plasticizers, cyclic volatile methyl siloxanes, UV-filters, pharmaceuticals, and microplastics in the European environment. Temporal trends demonstrate the effectiveness of European regulations on perfluorooctane sulfonic acid, pentabrominated diphenylethers and diethylhexyl phthalate, but also point to the rise of substitutes such as non-phthalate plasticizers and short-chain perfluoroalkyl substances. Other studies are wake-up calls indicating the emergence of currently unregulated compounds such as long-chain chlorinated paraffins. Ecological studies show temporal trends in biometric parameters and stable isotope signatures that suggest long-term changes in environmental conditions. Studies on biodiversity of ecosystems using environmental DNA are still in their beginnings, but here too there is evidence of shifts in community composition that can be linked to changing environmental conditions. This review demonstrates the value of ESBs (a) for describing the status of the environment, (b) for monitoring temporal changes in environmental pollution and the ecologic condition of ecosystems and thereby (c) for supporting regulators in prioritizing their actions towards the objectives of the Green Deal.

Making use of apex predator sample collections: an integrated workflow for quality assured sample processing, analysis and digital sample freezing of archived samples.

Using monitoring data from apex predators for chemicals risk assessment can provide important information on bioaccumulating as well as biomagnifying chemicals in food webs. A survey among European institutions involved in chemical risk assessment on their experiences with apex predator data in chemical risk assessment revealed great interest in using such data. However, the respondents indicated that constraints were related to expected high costs, lack of standardisation and harmonised quality criteria for exposure assessment, data access, and regulatory acceptance/application. During the Life APEX project, we demonstrated that European sample collections (i.e. environmental specimen banks (ESBs), research collection (RCs), natural history museums (NHMs)) archive a large variety of biological samples that can be readily used for chemical analysis once appropriate quality assurance/control (QA/QC) measures have been developed and implemented. We therefore issued a second survey on sampling, processing and archiving procedures in European sample collections to derive key quality QA/QC criteria for chemical analysis. The survey revealed great differences in QA/QC measures between ESBs, NHMs and RCs. Whereas basic information such as sampling location, date and biometric data were mostly available across institutions, protocols to accompany the sampling strategy with respect to chemical analysis were only available for ESBs. For RCs, the applied QA/QC measures vary with the respective research question, whereas NHMs are generally less aware of e.g. chemical cross-contamination issues. Based on the survey we derived key indicators for assessing the quality of biota samples that can be easily implemented in online databases. Furthermore, we provide a QA/QC workflow not only for sampling and processing but also for the chemical analysis of biota samples. We focussed on comprehensive analytical techniques such as non-target screening and provided insights into subsequent storage of high-resolution chromatograms in online databases (i.e. digital sample freezing platform) to ultimately support chemicals risk assessment.

Comprehensive screening of polar emerging organic contaminants including PFASs and evaluation of the trophic transfer behavior in a freshwater food web.

Bioaccumulation and trophic transfer of persistent legacy contaminants have been intensively characterized, but little is known on the contaminants of emerging concern (CECs) in freshwater food webs. Herein, we comprehensively screened CECs with a focus on polar substances and further evaluated their trophic transfer behavior in selected items from the food web of Lake Templin, Germany. Weselected one plankton, two mussel, and nine fish samples covering three trophic levels. With an effective multi-residue sample preparation method and high-resolution mass spectrometry-based target, suspect, and non-target screening, we characterized 477 targets and further screened unknown features in complex biota matrices. Of the 477 targets, 145 were detected and quantified in at least one species (0.02-3640 ng/g, dry weight). Additionally, the suspect and non-target analysis with experimental mass spectra libraries and in silico techniques (MetFrag and SIRIUS4/CSI:FingerID) enabled further identification of 27 unknown compounds with 19 confirmed by reference standards. Overall, the detected compounds belong to a diverse group of chemicals, including 71 pharmaceuticals, 27 metabolites, 26 pesticides, 16 per- and polyfluoroalkyl substances (PFASs), 4 plasticizers, 3 flame retardants, 11 other industrial chemicals and 14 others. Moreover, we determined the trophic magnification factor (TMF) of 34 polar CECs with >80% detection frequency, among which 6 PFASs including perfluorooctane sulfonic acid (PFOS), perfluorodecanoic acid (PFDA), perfluorohexane sulfonic acid (PFHxS), perfluorotridecanoic acid (PFTrA), perfluorotetradecanoic acid (PFTeA), and perfluoroundecanoic acid (PFUnA), exhibited biomagnification potential (TMF =1.8 - 4.2, p < 0.05), whereas 5 pharmaceuticals (phenazone, progesterone, venlafaxine, levamisole, and lidocaine) and 1 personal care product metabolite (galaxolidone) showed biodilution potential (TMF = 0.4 - 0.6, p < 0.05).

30 years trends of microplastic pollution: Mass-quantitative analysis of archived mussel samples from the North and Baltic Seas.

Microplastics (MP) are ubiquitous throughout the environment as a result of an ongoing, increasing, but also lavish use, of plastics over time and its inherent persistence. In contrast, there are almost no data that allow drawing conclusions about the evolution of plastic pollution in the environment over the past decades. This study investigates the MP load in blue mussels from the North and Baltic Sea archived by the German Environmental Specimen Bank in a time series covering almost 30 years. Samples were enzymatically and chemically oxidative digested for MP extraction and subsequent analyzed mass-quantitatively for nine common polymer clusters by pyrolysis gas chromatography-mass spectrometry. Seven polymer clusters were detected in mussel tissue. Summed MP levels were at ppm levels (<20 µg/g mussel, dry weight). North Sea samples reflected a gradual increase from the 1980s/90s to the 2000s whereas those from Baltic Sea showed consistently higher, rather constant MP levels similar to the North Sea site later than 2000. Polymer composition of both sites stood out by cluster (C) of C-PVC and C-PET at both sites. Mussels from Baltic Sea site had larger C-PE and C-PP proportions. Opposed polymer- and site-specific trends indicated both regional and trans-regional MP sources for different polymer clusters. The MP composition of mussels showed strong similarities with adjacent sediment and water samples. The study introduces a relevant dataset addressing the temporal development of MP pollution. It emphasizes a high indicative potential of environmental MP composition/loads received by mussels but raises the necessity on adequate control materials accompany such kind of studies.

Equilibrium sampling of suspended particulate matter as a universal proxy for fish and mussel monitoring.

Bioaccumulation of persistent and hydrophobic organic compounds in the aquatic environment puts secondary consumers, such as fish, at risk. To assess their exposure, monitoring programs with high numbers of individuals have been conducted worldwide over decades that require major efforts and raise ethical issues. This study aimed at testing suspended particulate matter (SPM) as an alternative and accessible abiotic matrix to estimate the internal exposure concentrations of such chemicals in fish and mussels. Muscle tissues of bream (Abramis brama), tissues of zebra mussels (Dreissena polymorpha) and SPM were collected from four major German rivers, Elbe, Danube, Saar and Saale, in 2018 within the national monitoring program of the German Environmental Specimen Bank. We used (i) total solvent extraction for biota samples to quantify the lipid-normalized concentrations of polychlorinated biphenyls, polycyclic aromatic hydrocarbons and hexachlorobenzene and (ii) passive equilibrium sampling of SPM to derive equilibrium partitioning concentrations in lipids and (iii) set these independent data sets into context. Since the ratio of lipid-normalized concentration / equilibrium partitioning concentration in lipids was in most cases < 1.0, SPM may serve as a conservative proxy for the internal concentration of bream and mussels, although bream of high age (i.e., older than 10 years) showed a tendency for this ratio to exceed 1.0. This observation indicates that age-dependent biomagnification can exceed the predictions based on thermodynamic equilibrium relative to SPM.

Tissue concentrations of per- and polyfluoroalkyl substances (PFAS) in German freshwater fish: Derivation of fillet-to-whole fish conversion factors and assessment of potential risks.

The European Water Framework Directive requires monitoring of bioaccumulative contaminants in fish to assess risks to human health by fish consumption and wildlife by secondary poisoning of predators. The list of priority substances for which environmental quality standards (EQSs) have been derived covers also perfluorooctane sulfonic acid (PFOS). No EQSs have yet been set for other per- and polyfluoroalkyl substances (PFAS) that are frequently detected in fish and of which some have a non-negligible risk potential compared to PFOS. As a case study, burdens for a set of PFAS were investigated for different fish species from five German freshwater sites and a Baltic Sea lagoon. PFAS concentrations were determined for composite samples of both, fillet and whole fish. On average, sum concentrations of C9-C14 perfluoroalkyl carboxylic acids, which will be banned in the European Union in 2023, reached 87% and 82% of the PFOS burdens in fillet and whole fish, respectively. The potential risk of several PFAS other than PFOS was assessed using a previously suggested relative potency factor approach, which is also applied for a proposed EQS revision. Only five of 36 fillet samples (mostly perch) exceeded the current EQS for PFOS alone. By contrast, all fillet samples exceeded the newly proposed draft EQS, which considers potential effects of further PFAS but also a lower tolerable intake value. Additionally, the dataset was used to derive fillet-to-whole fish conversion factors, which can be applied to assess human health risks by consumption of fillet if only whole fish concentrations are available.

Long-Term Trends of Per- and Polyfluoroalkyl Substances (PFAS) in Suspended Particular Matter from German Rivers Using the Direct Total Oxidizable Precursor (dTOP) Assay.

Suspended particulate matter (SPM) from 13 riverine sampling sites of the German Environmental Specimen Bank collected between 2005 and 2019 was retrospectively investigated for per- and polyfluoroalkyl substances (PFAS). The samples were analyzed both by target analysis for 41 PFAS and by a modified total oxidizable precursor (dTOP) assay to capture also unknown precursors. Temporal trends and spatial differences were investigated by generalized linear modeling (GLM). Time trend analysis across all rivers showed decreasing trends for ∑PFCA and ∑PFSA concentrations in SPM. Trends based on target analysis (∑PFCAtarget: -10.0%, ∑PFSAtarget: -8.2%) were more pronounced than in the dTOP analysis (∑PFCAdTOP: -4.2%; ∑PFSAdTOP: -5.3%), suggesting that conventional target analysis overestimated actual decreases as precursors are not considered. ∑PFAS concentrations determined by dTOP assay were 1.3-145 times higher as compared to target analysis, indicating substantial amounts of unknown precursors in the samples. The ∑PFASdTOP/∑PFAStarget ratio increased at all sites between 2005 and 2019. Contamination was highest in SPM from the Elbe tributary Mulde downstream of a large industrial park. The results underscore the need to go beyond conventional target analysis and include precursors when assessing PFAS contamination in the environment. The dTOP assay is a suitable tool for this purpose.

Identifying emerging environmental concerns from long-chain chlorinated paraffins towards German ecosystems.

Germany is one of several major European producers of chlorinated paraffins (CPs). This study showed that not only the legacy short-chain products (SCCPs, C10-13), but also the current-use medium- and long-chain products (MCCPs, C14-17; LCCPs, C>17) as well as the very-short-chain impurities (vSCCPs, C<10) are ubiquitous in the 72 samples collected from the coastal, terrestrial, and freshwater ecosystems across the country. The concentrations of LCCPs surpassed those of the other CPs in 40% of the biota samples. Archived bream samples collected downstream of a CP-manufacturing factory showed decreasing temporal trends of (v)SCCPs and relatively constant levels of MCCPs from 1995 to 2019; however, the overall levels of LCCPs have increased by 290%, reflecting the impact of chemical regulation policies on changes in CP production. A visualization algorithm was developed for integrating CP results from various matrices to illustrate spatial tendencies of CP pollution. Higher levels of (v)SCCPs were indicated in the former West Germany region, while MCCP and LCCP concentrations did not seem to differ between former East and West Germany, suggesting relatively equal production and use of these chemicals after the German Reunification. The results provide an early warning signal of environmental concerns from LCCPs on the eve of their booming global production and use.

Hg isotopic composition of one-year-old spruce shoots: Application to long-term Hg atmospheric monitoring in Germany.

The Hg isotopic composition of 1-year-old Norway spruce (Picea abies) shoots collected from Saarland cornurbation Warndt, Germany, since 1985 by the German Environmental Specimen Bank, were measured for a better understanding of the temporal trends of Hg sources. The isotopic data showed that Hg was mainly taken up as gaseous element mercury (GEM) and underwent oxidation in the spruce needles; this led to a significant decrease in the δ202Hg compared with the atmospheric Hg isotopic composition observed for deciduous leaves and epiphytic lichens. Observation of the odd mass-independent isotopic fractionation (MIF) indicated that Δ199Hg and Δ201Hg were close to but slightly lower than the actual values recorded from the atmospheric measurement of the GEM isotopic composition in non-contaminated sites in U.S. and Europe, whereas observation of the even-MIF indicated almost no differences for Δ200Hg. This confirmed that GEM is a major source of Hg accumulation in spruce shoots. Interestingly, the Hg isotopic composition in the spruce shoots did not change very significantly during the study period of >30 years, even as the Hg concentration decreased significantly. Even-MIF (Δ200Hg) and mass-dependent fractionation (MDF) (δ202Hg) of the Hg isotopes exhibited slight decrease with time, whereas odd-MIF did not show any clear trend. These results suggest a close link between the long-term evolution of GEM isotopic composition in the air and the isotopic composition of bioaccumulated Hg altered by mass-dependent fraction in the spruce shoots.

Long-term trends of airborne halogenated flame retardants (HFRs) by means of tree leaf and shoot analyses.

The historical air pollution with halogenated flame retardants (HFRs) in Germany was assessed by investigating tree leaf and shoot samples which have been archived in the German environmental specimen bank. Samples covered the period from 1985 to 2016. 43 HFRs comprising polybrominated diphenyl ethers as well as emerging brominated and chlorinated compounds such as Dechlorane Plus, DBDPE, or DPTE, were analysed in 115 samples from ten sub sites originating from six areas characterised by different land uses, including urban as well as a background site. HFRs were observed in each sample showing the widespread distribution of HFRs in Germany in tree leaves and shoots as bioindicators of past and present atmospheric pollution. Analytes observed at elevated concentrations were BDE 209, DBDPE and DPTE. Observed HFR-levels differed between analytes as well as sampling locations, particularly prior to the year 2000. They were typically highest at conurbation areas. Concentrations at the background site often belonged to the lowest ones observed, however, lowest values were not exclusively found there. The quantification frequencies appeared to decrease from the past to most recent samples. With few exceptions, atmospheric pollution of both, legacy and emerging HFRs, decreased significantly.

Exploring unknown per- and polyfluoroalkyl substances in the German environment - The total oxidizable precursor assay as helpful tool in research and regulation.

Limnetic, marine and soil samples of the German environmental specimen bank (ESB) were analyzed for per- and polyfluoroalkyl substances (PFAS) using target analysis and a modified total oxidizable precursor (TOP) assay (direct TOP assay (dTOP)) that works without prior extraction. Target analysis determined ∑PFAS concentrations in bream livers of 8.7-282 µg kg-1 wet weight (ww) in 2019, with highest contaminations in the Rhine and lower Elbe. In bream fillet, concentrations were lower (<0.5-10.6 µg kg-1 ∑PFAS). Contamination of suspended particulate matter (SPM) was highest in the upper Elbe downstream the Czech border (5.5 µg kg-1 dry weight (dw) in 2018). Herring gull eggs from the North and Baltic Seas showed ∑PFAS levels around 53.0-69.6 µg kg-1 ww in 2019. In soil, concentrations ranged between <0.5 and 4.6 µg kg-1 dw with highest levels in the Dueben Heath near Leipzig and the low mountain range Solling. PFOS dominated in most samples. Of the targeted precursors, only FOSA, EtFOSAA, MeFOSAA, 6:2-FtS and 6:2 diPAP were found. Replacement chemicals (ADONA, HFPO-DA, F-53B) were not detected. The dTOP assay revealed that considerable amounts of precursors were present at most riverine sampling sites. Particularly high precursor concentrations were observed in samples from the Upper Elbe at the Czech border and the Upper and Middle Rhine. In herring gull eggs and most soil samples, though, concentrations of precursors were low. Time trend analysis showed decreasing trends for most detected PFAS since 2005. In SPM, however, C4-C6 perfluoroalkyl carboxylic acids seem to increase indicating growing use of precursors based on shorter fluorinated chains. The results demonstrate that target analysis detects only a minor fraction of the PFAS burdens in environmental samples. The dTOP assay can support risk assessment and chemical monitoring with more comprehensive exposure data of the actual contamination.

Determination of low environmental free cyanide concentrations in freshwaters.

Cyanide compounds are naturally emitted into the environment in low levels by degradation processes or emitted from anthropogenic sources. In surface water, complex cyanide compounds as well as "free cyanide" are present. The latter term covers hydrogen cyanide and cyanide compounds which easily liberate hydrogen cyanide under slightly acidic conditions. Especially free cyanide may cause adverse effects in the environment. To exclude negative impacts on freshwater systems, in the context of the European Water Framework Directive (WFD), preventive regulatory activities for free cyanide are currently under discussion. However, established analytical methods for quantification of free cyanide only obtain limits of quantification (LOQs) in the range of 1 µg L-1. Thus, these methods are not sufficiently sensitive for a potential environmental quality standard (EQS) compliance monitoring at water concentrations below the current predicted no effect concentration (PNEC) level of free cyanide. In the present study, a standardized continuous flow analysis (CFA) method for quantification of low free cyanide concentrations was adapted by applying a special system which allows an ultra-sensitive photometric detection of a colored cyanide derivative. By this means, LOQs in a range of one magnitude below the PNEC are achievable. The method was validated according to ISO/IEC 17025 requirements. Free cyanide concentrations in tested surface water samples from a small river and a barrier lake with low anthropogenic influences were very low and clearly below the PNEC. The results prove that the adapted CFA method is suitable for the analysis of low concentration free cyanide in freshwaters and appropriate for a possible EQS compliance monitoring.

Human biomonitoring of per- and polyfluoroalkyl substances in German blood plasma samples from 1982 to 2019.

The findings of per- and polyfluoroalkyl substances (PFAS) in humans and the environment all over the world have raised concerns and public awareness for this group of man-made chemicals. In the last three decades, this led to different regulatory restrictions for specific PFAS as well as shifts in the production and usage of these substances. In this study, we analyzed the PFAS levels of 100 human blood plasma samples collected from 2009 to 2019 for the German Environmental Specimen Bank (ESB) to further elucidate the time course of exposure towards this substance group as shown by Schröter-Kermani et al., (2013) with samples from 1982 to 2010. A spectrum of 37 PFAS, including perfluorocarboxylic (PFCA) and -sulfonic acids (PFSA) as well as potential precursors and substitutes like ADONA, GenX or F-53B was analyzed by UHPLC coupled with high-resolution mass spectrometry. Validation was successful for 33 of the substances. The two legacy substances perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were detected in every sample of the 2009-2019 dataset and showed the highest concentrations with ranges of 0.27-14.0 ng/mL and 1.21-14.1 ng/mL, respectively. A significant portion of total PFOS analytes was present as branched isomers (mean: 34 ± 7%). High detection frequencies of 95% and 82% were also found for perfluorohexane sulfonic acid (PFHxS) and perfluorononanoic acid (PFNA), respectively, but in lower concentrations (PFHxS:

Aquatic suspended particulate matter as source of eDNA for fish metabarcoding.

The use of environmental DNA (eDNA) for monitoring aquatic macrofauna allows the non-invasive species determination and measurement of their DNA abundance and typically involves the analysis of eDNA captured from water samples. In this proof-of-concept study, we focused on the novel use of eDNA extracted from archived suspended particulate matter (SPM) for identifying fish species using metabarcoding, which benefits from the prospect of retrospective monitoring and also analysis of fish communities through time. We used archived SPM samples of the German Environmental Specimen Bank (ESB), which were collected using sedimentation traps from different riverine points in Germany. Environmental DNA was extracted from nine SPM samples differing in location, organic content, and porosity (among other factors) using four different methods for the isolation of high-quality DNA. Application of the PowerSoil DNA Isolation Kit with an overnight incubation in lysis buffer, resulted in DNA extraction with the highest purity and eDNA metabarcoding of these eDNA fragments was used to detect a total of 29 fish taxa among the analyzed samples. Here we demonstrated for the first time that SPM is a promising source of eDNA for metabarcoding analysis, which could provide valuable retrospective information (when using archived SPM) for fish monitoring, complementing the currently used approaches.

Per- and polyfluoroalkyl substances in the German environment - Levels and patterns in different matrices.

Per- and polyfluoroalkyl substances (PFAS) in the environment mostly originate from emissions of previously unregulated PFAS. However, there are also many documented incidents of accidental releases. To track such releases, it is essential to distinguish between typical background contamination and legally relevant incidents. This requires a comprehensive overview of all PFAS present in the environment, which is currently only possible to a limited extent due to the large variety of individual compounds. In the present study, a multimethod for capturing 41 PFAS including perfluoroalkyl acid (PFAA) precursors is introduced. The applicability of the method was tested on terrestrial, freshwater and marine samples from the German Environmental Specimen Bank (ESB), thereby providing a rough overview of PFAS contamination in German environment. Special focus was put on soil samples from ESB sites across Germany in comparison to soil samples from a polluted site in south-west Germany. The method was successfully applied to environmental samples. In total, 31 PFAS were detected, among them PFAA precursors and fluorinated ethers. Substance patterns differed between sites and matrices. In ESB soil samples from 2014 (n = 11), the sum of all captured PFAS ranged between 0.75 and 19.5 µg kg-1 dry weight (dw), while concentrations between 416 µg kg-1 and 3530 µg kg-1 were detected in samples from the incident site (n = 10). In other matrices, total PFAS concentrations were magnitudes lower. Highest concentrations were observed for PFOS in bream livers from the Saale (226 µg kg-1). Given the heterogeneous patterns, it will require further broadly-based monitoring data to allow for a solid estimation of relevant background levels. The data provided here may support the differentiation between background levels and hotspot contaminations.

Retrospective analysis of cyclic volatile methylsiloxanes in archived German fish samples covering a period of two decades.

Cyclic volatile methylsiloxanes (cVMS) are widely applied chemicals used as intermediates in the production of silicon polymers or as ingredients in personal care products. cVMS are under scrutiny due to their environmental properties and their potential for long-range atmospheric transport, persistence and food web magnification. In 2018, the cVMS octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) were identified as Substances of Very High Concern (SVHC) under the European REACH regulation. To obtain current data on the presence of cVMS in German waters, the spatial and temporal occurrence of D4, D5 and D6 in fillets of bream from major rivers archived in the German Environmental Specimen Bank (ESB) was analyzed with a GC-ICP-MS/MS coupling method. The spatial comparison of 17 sites for the year 2017 revealed that highest cVMS burdens occurred in samples from the Saar river (near to the French/German border). cVMS levels in fish from a lake in northern Germany did not exceed the limits of detection. For selected sites, time series covering the period from 1995 to 2017 were investigated. In most years D5 concentrations in fish were clearly higher than the observed D4 and D6 concentrations. Overall maximum D4 and D5 concentrations (about 320 and 7600 ng g-1 wet weight, respectively) were found at one Saar site in 2009. In three of five analyzed time series D5 concentrations peaked 2007-2011. In recent years, cVMS levels in fish decreased at almost all sites. To allow an assessment of the relevance of the detected cVMS fish concentrations these were compared to environmental quality standards (EQS) for D4 and D5 which were recently enacted in the context of the Swedish implementation of the European Water Framework Directive (WFD). The D5 EQS in fish was exceeded at four sites in several years in the investigated period and in the Saar even till 2017.