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Food web on ice - Investigation of the bioaccumulation of chemicals in an exemplary food chain

Trophic magnification factors (TMFs) have been derived in a variety of different aquatic eco-systems worldwide to investigate accumulation patterns of environmentally relevant chemicals. Not only is the TMF interesting for chemicals’ risk assessment related questions, but also for monitoring aspects under the European Water Framework Directive (WFD). This study is the first TMF study con-ducted in a German freshwater ecosystem, that is, Lake Templin near Potsdam. Aim of the study was to investigate the food web magnification following existing guidance to derive reliable TMFs that could be used for regulatory purposes. A sampling campaign yielded 15 biota samples covering about three trophic levels, which have been processed and cryo-preserved following standardized protocols of the German Environmental Specimen Bank (ESB). The samples remain available for future analysis and, thus, form a “food web on ice”. These large-scale food web samples are ready-to-use for a broad variety of analyses. In a first step, a plausibility check was performed. Different persistent organic pollutants (POPs), which are known to magnify in food webs and are not readily metabolized, serve as benchmarks. It could be shown that for nearly all of the POPs analyzed, the TMFs are significantly above 1. In a few cases, an enrichment is also seen, but not statistically relevant. Since not only POPs with lipophilic accumulation properties were analyzed, it could be concluded that the food web on ice samples from Lake Templin can be used to characterize the trophic magnification potential of further substances with less investigated bioaccumulation properties present in the samples. To this end, several ⁠ PFAS ⁠, pharmaceuticals, pesticides and methyl siloxanes were investigated in the samples to derive their TMFs. Veröffentlicht in Texte | 137/2022.

Comparison of species sensitivity of Daphnia and fish in acute and chronic testing

Based on the animal welfare concept (Art. 13, Art. 25), the REACh Regulation (EC 1907/2006) provides several options to avoid the long term fish toxicity test. About 240 substances from the ECHA and ICS database including 73 pesticides are analysed for species sensitivity differences and acute to chronic ratios to evaluate whether and when chronic fish toxicity tests can be avoided without underestimating environmental risk. Only studies that have been conducted in line with guidelines recommended in the EU guidance documents are used for this study. Sensitivity comparison of fish and Daphnia toxicity indicates that none of both trophic levels is generally more sensitive in acute or long term testing. Based on the finding that the sensitivity in chronic testing is associated with sensitivity in acute testing a classification scheme for acute sensitivity comparison was proposed to contribute the integrated testing strategy. Veröffentlicht in Texte | 87/2015.

Mercury levels and trends (1993-2009) in bream (Abramis brama L.) and zebra mussels (Dreissena polymorpha) from German surface waters

Lepom, Peter; Irmer, Ulrich; Wellmitz, Jörg Chemosphere 86 (2012), 2, 202-211 Mercury concentrations have been analysed in bream (Abramis brama L.) and zebra mussels (Dreissena polymorpha) collected at 17 freshwater sites in Germany from 1993-2009 and 1994-2009, respectively, within the German Environmental Specimen programme. Mercury concentrations in bream ranged from 21 to 881 ng g -1 wet weight with lowest concentrations found at the reference site Lake Belau and highest in fish from the river Elbe and its tributaries. Statistical analysis revealed site-specific differences and significant decreasing temporal trends in mercury concentrations at most of the sampling sites. The decrease in mercury levels in bream was most pronounced in fish from the river Elbe and its tributary Mulde, while in fish from the river Saale mercury levels increased. Temporal trends seem to level off in recent years. Mercury concentrations in zebra mussels were much lower than those in bream according to their lower trophic position and varied by one order of magnitude from 4.1 to 42 ng g -1 wet weight (33-336 ng g -1 dry weight). For zebra mussels, trend analyses were performed for seven sampling sites at the rivers Saar and Elbe of which three showed significant downward trends. There was a significant correlation of the geometric mean concentrations in bream and zebra mussel over the entire study period at each sampling site (Pearson’s correlation coefficient = 0.892, p = 0.00002). A comparison of the concentrations in bream with the environmental quality standard (EQS) of 20 ng g -1 wet weight set for mercury in biota by the EU showed that not a single result was in compliance with this limit value, not even those from the reference site. Current mercury levels in bream from German rivers exceed the EQS by a factor 4.5-20. Thus, piscivorous top predators are still at risk of secondary poisoning by mercury exposure via the food chain. It was suggested focusing monitoring of mercury in forage fish (trophic level 3 or 4) for compliance checking with the EQS for biota and considering the age dependency of mercury concentrations in fish in the monitoring strategy. doi:10.1016/j.chemosphere.2011.10.021

Survey of patterns, levels, and trends of perfluorinated compounds in aquatic organisms and bird eggs from representative German ecosystems

Rüdel, Heinz; Müller, Josef; Jürling, Heinrich; Bartel-Steinbach, Martina; Koschorreck, Jan Environ Sci Pollut Res 18 (2011), 9, 1457-1470 Samples from the German Environmental Specimen Bank (ESB) covering particularly the years 1994-1996, 2000-2002, and 2006-2009 were analyzed for perfluorinated compounds (PFC; mainly C4-C13 carboxylic and sulfonic acids) to gain an overview on current PFC levels and patterns in marine, limnetic, and terrestrial biota; to assess their concentrations in different trophic levels; and to investigate whether risk management measures for PFC are successful. Specimens, either standardized annual pooled samples (blue mussels, eelpout liver, bream liver, pigeon eggs) or individual single samples (cormorant eggs, rook eggs), were collected for the German ESB program from representative sampling sites according to documented guidelines. After appropriate extraction, PFC were quantified under ISO/IEC 17025 accreditation by HPLC/MS-MS with isotopically labeled internal standards. Limits of quantification (LOQs) were 0.2-0.5 ng/g. Data are reported on a wet weight basis. In most samples the predominant PFC was perfluorooctane sulfonic acid (PFOS). However, in marine mussels from North and Baltic Seas, PFOS levels were mostly below the LOQ, but low residues of PFOS amide were found which declined in recent years. Livers of eelpout showed maximum concentrations of 15-25 ng/g PFOS in the period 2000-2002 and low amounts of perfluoropentanoate in all years. Beside PFOS (median 48 ng/g) several PFC could be determined in cormorant eggs sampled in 2009 from a Baltic Sea site. For a freshwater ecosystem, current PFC burdens for cormorant eggs were even higher (median 400 ng/g PFOS). Livers of bream from rivers showed concentrations of 130-260 ng/g PFOS, but for bream from a reference lake levels were only about 6 ng/g. In contrast to cormorants, eggs of rook and feral pigeon from terrestrial ecosystems displayed only low PFC burdens (up to 6 ng/g PFOS). Generally, PFC levels were lower in marine than in freshwater biota. PFC burdens were higher in biota from the ESB-North Sea sites than in Baltic Sea organisms. Levels of PFC were quite high especially in top predators of both limnetic and marine ecosystems. Only low PFC levels were detected in eggs of terrestrial birds. A decrease of PFOS levels from maximum values around the year 2000 observed at least in North Sea biota may be a result of a production cease and shifts in marketing pattern. doi:10.1007/s11356-011-0501-9

Decreasing δ13C and δ15N values in four coastal species at different trophic levels indicate a fundamental food-web shift in the southern North and Baltic Seas between 1988 and 2016

Cormann, Anna-Marie; Schwemmer, Philipp; Mercker, Moritz; Asmus, Harald; Klein, Roland; Boner, Markus; Hofem, Sabine; Koschorreck, Jan; Garthe, Stefan Environ Monit Assess 190 (2018), 8, 461; online 11. Juli 2018 Marine ecosystems are exposed to increasing human pressures and climatic change worldwide. It has therefore become essential to describe ecosystem statuses with respect to multinational protection schemes, often necessitating long-term monitoring programmes. Changes in the food-web structure, which can be monitored via stable isotope measurements, represent an important descriptor of the status of marine ecosystems. We investigated long-term changes (29 years) in isotopic values (δ13C and δ15N) in four indicative organisms at different trophic levels in the southern North and Baltic Seas: bladderwrack (Fucus vesiculosus), blue mussel (Mytilus ssp.), eelpout (Zoarces viviparus), and herring gull (Larus argentatus). Time series analyses using generalised additive models revealed largely consistent declines in δ13C and δ15N throughout all trophic levels of the coastal food web at all study sites, indicating a clear change in these coastal regions from 1988 to 2016. There were no clear long-term patterns in egg biometrics for herring gulls, except for a consistent increase in eggshell thickness. The declines in stable isotope values were in line with the results of previous long-term studies of single higher-trophic-level species, which suggested that the noted changes were mainly caused by altered foraging patterns of the studied species. The current results demonstrate that declines in δ13C and δ15N have occurred throughout the whole food web, not just in particular species. We discuss the possible reasons for the decrease in stable isotope values, including decreasing eutrophication and an increase in terrestrial carbon sources. doi: 10.1007/s10661-018-6827-8

Biota monitoring under the Water Framework Directive: On tissue choice and fish species selection

Fliedner, Annette; Rüdel, Heinz; Lohmann, Nina; Buchmeier, Georgia; Koschorreck, Jan Environmental Pollution 235 (2018), 129-140; online 23. Dezember 2017 The study addresses the topic of suitable matrices for chemical analysis in fish monitoring and discusses the effects of data normalization in the context of the European Water Framework Directive (WFD). Differences between species are considered by comparing three frequently monitored species of different trophic levels, i.e., chub (Squalius cephalus, n = 28), (bream, Abramis brama, n = 11), and perch (Perca fluviatilis, n = 19) sampled in the German Danube. The WFD priority substances dioxins, furans and dioxin-like polychlorinated biphenyls (PCDD/F + dl-PCB), polybrominated diphenyl ethers (PBDE), α-hexabromocyclododecane (α-HBCDD), hexachlorobenzene (HCB), mercury (Hg), and perfluorooctane sulfonic acid (PFOS) as well as non-dioxin-like (ndl)-PCB were analyzed separately in fillet and carcass and whole body concentrations were calculated. Hg was analyzed in individual fish fillets and carcasses, all other substances were determined in pool samples, which were compiled on the basis of fish size (3 chub pools, 1 bream pool, 2 perch pools). The data were normalized to 5% lipid weight (or 26% dry mass in the case of Hg and PFOS) for comparison between matrices and species. Hg concentrations were generally higher in fillet than in whole fish (mean whole fish-to-fillet ratio: 0.7) whereas all other substances were mostly higher in whole fish. In the case of lipophilic substances these differences leveled after lipid normalization. Significant correlations (p ≤ .05) were detected between Hg and fish weight and age. Hg concentrations varied least among younger fish. PCDD/F, dl-PCB, ndl-PCB, PBDE, α-HBCDD and HCB correlated significantly (p ≤ .05) with lipid concentrations. Fillet-to-whole fish conversion equations and/or conversion factors were derived for all substances except α-HCBDD. Although more data also for individual fish would be desirable the results are nevertheless a step on the way to translate fillet concentrations of priority substances to whole fish concentrations. doi:10.1016/j.envpol.2017.12.052

Levels, accumulation patterns and retrospective trends of perfluoroalkyl acids (PFAAs) in terrestrial ecosystems over the last three decades

Falk, Sandy; Stahl, Thorsten; Fliedner, Annette; Rüdel, Heinz; Tarricone, Kathrin; Brunn, Hubertus; Koschorreck, Jan Environmental Pollution (2019); online 3. Januar 2019 As a result of their ubiquitous presence in the environment perfluoroalkyl acids (PFAAs) have been demonstrated in numerous organisms worldwide, in particular in those of higher trophic levels. The fact that PFAAs have been detected in various human matrices, together with the resultant potential human health risks, knowledge of possible paths of entry and distribution in various ecosystems, is of great importance. In this context pooled samples of terrestrial ecosystems – roe deer liver (n = 141), earthworms (n = 44) as well as leaves from beech and poplar trees (n = 70) – from the year 1989–2015 were obtained from the German Environmental Specimen Bank and examined for the presence of 11 PFAAs for the first time. In addition to determining individual and total PFAA concentrations, temporal trends have been deduced in order to determine the effectiveness of regulatory measures. The highest total mean concentration of PFAAs (sum of the concentrations of the 11 analytes) were 9.9 μg/kg in the roe deer liver samples, followed by earthworm samples with a mean PFAA concentration of 3.5 μg/kg and leaves with a mean total concentration of 2.5 μg/kg. In regard to temporal trends there was a significant reduction of concentrations for perfluorooctane sulfonate, perfluorooctanoic acid, perfluorononanoic acid and perfluorodecanoic acid in roe deer liver from 2003 to 2015, an indication of the effectiveness of regulatory measures. The same is true for the perfluorooctane sulfonate concentrations in earthworms and for perfluorooctanoic acid concentrations in the leaves. In contrast, an increase in perfluorobutanoic acid concentrations was observed from 2003 to 2015 in all three matrices. In summary it must be noted that in spite of the discernible effectiveness of minimization strategies, PFAAs are still detectable in terrestrial matrices and concentrations of other PFAAs as perfluorobutanoic acid appear to be increasing. doi: 10.1016/j.envpol.2018.12.095

Biota monitoring and the Water Framework Directive - can normalization overcome shortcomings in sampling strategies?

Fliedner, Annette; Rüdel, Heinz; Teubner, Diana; Buchmeier, Georgia; Lowis, Jaqueline; Heiss, Christiane; Wellmitz, Jörg; Koschorreck, Jan Environ Sci Pollut Res Int. (2016), online 18. August 2016 We compare the results of different monitoring programs regarding spatial and temporal trends of priority hazardous substances of the European Water Framework Directive (WFD). Fish monitoring data for hexachlorobenzene (HCB), mercury (Hg), and perfluorooctane sulfonic acid (PFOS) sampled in German freshwaters between the mid-1990s and 2014 were evaluated according to the recommendations of the 2014 adopted WFD guidance document on biota monitoring, i.e., normalization to 5 % lipid content (HCB) or 26 % dry mass (Hg, PFOS) and adjustment to trophic level (TL) 4. Data of the German Environmental Specimen Bank (ESB) (annual pooled samples of bream) were compared to monitoring data of the German federal states (FS), which refer to individual fish of different species. Significant decreasing trends (p < 0.01) were detected for Hg in bream (Abramis brama) sampled by both, the ESB and the FS between 1993 and 2013 but not for FS samples comprising different fish species. Data for HCB and PFOS were more heterogeneous due to a smaller database and gave no consistent results. Obviously, normalization could not compensate differences in sampling strategies. The results suggest that the data treatment procedure proposed in the guidance document has shortcomings and emphasize the importance of highly standardized sampling programs in trend monitoring or whenever results between sites have to be compared. doi:10.1007/s11356-016-7442-2

Meßprogramm Trophie (StALU VP Stralsund)

Erfassung des Trophiezustandes an phytoplanktonbeeinflußten Meßstellen an Fließgewässern.

Meßprogramm Trophie (StALU WM Schwerin)

Erfassung des Trophiezustandes an phytoplanktonbeeinflußten Meßstellen an Fließgewässern.

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