Significant Turning Point: Common Buzzard (Buteo buteo) Exposure to Second-Generation Anticoagulant Rodenticides in the United Kingdom.

Second-generation anticoagulant rodenticides (SGARs) are widely used to control rodent populations, resulting in the serious secondary exposure of predators to these contaminants. In the United Kingdom (UK), professional use and purchase of SGARs were revised in the 2010s. Certain highly toxic SGARs have been authorized since then to be used outdoors around buildings as resistance-breaking chemicals under risk mitigation procedures. However, it is still uncertain whether and how these regulatory changes have influenced the secondary exposure of birds of prey to SGARs. Based on biomonitoring of the UK Common Buzzard (Buteo buteo) collected from 2001 to 2019, we assessed the temporal trend of exposure to SGARs and statistically determined potential turning points. The magnitude of difenacoum decreased over time with a seasonal fluctuation, while the magnitude and prevalence of more toxic brodifacoum, authorized to be used outdoors around buildings after the regulatory changes, increased. The summer of 2016 was statistically identified as a turning point for exposure to brodifacoum and summed SGARs that increased after this point. This time point coincided with the aforementioned regulatory changes. Our findings suggest a possible shift in SGAR use to brodifacoum from difenacoum over the decades, which may pose higher risks of impacts on wildlife.

The importance of in-year seasonal fluctuations for biomonitoring of apex predators: A case study of 14 essential and non-essential elements in the liver of the common buzzard (Buteobuteo) in the United Kingdom.

Trace elements are chemical contaminants spread in the environment by anthropogenic activities and threaten wildlife and human health. Many studies have investigated this contamination in apex raptors as sentinel birds. However, there is limited data for long-term biomonitoring of multiple trace elements in raptors. In the present study, we measured the concentrations of 14 essential and non-essential trace elements in the livers of the common buzzard (Buteo buteo) collected in the United Kingdom from 2001 to 2019 and investigated whether concentrations have changed during this period. In addition, we estimated the importance of selected variables for modelling element accumulations in tissues. Except for cadmium, hepatic concentrations of harmful elements in most buzzards were lower than the biological significance level of each element. Hepatic concentrations of certain elements, including lead, cadmium, and arsenic, varied markedly seasonally within years. Their peak was in late winter and trough in late summer, except copper which showed an opposite seasonal pattern. In addition, lead in the liver consistently increased over time, whereas strontium showed a decreasing trend. Hepatic concentrations of cadmium, mercury, and chromium increased with age, whereas selenium and chromium were influenced by sex. Hepatic concentrations of arsenic and chromium also differed between different regions. Overall, our samples showed a low risk of harmful effects of most elements compared to the thresholds reported in the literature. Seasonal fluctuation was an important descriptor of exposure, which might be related to the diet of the buzzard, the ecology of their prey, and human activities such as the use of lead shot for hunting. However, elucidating reasons for these observed trends needs further examination, and biomonitoring studies exploring the effects of variables such as age, sex, and seasonality are required.

Assessment of contaminants of emerging concern in European apex predators and their prey by LC-QToF MS wide-scope target analysis.

Apex predators are good indicators of environmental pollution since they are relatively long-lived and their high trophic position and spatiotemporal exposure to chemicals provides insights into the persistent, bioaccumulative and toxic (PBT) properties of chemicals. Although monitoring data from apex predators can considerably support chemicals' management, there is a lack of pan-European studies, and longer-term monitoring of chemicals in organisms from higher trophic levels. The present study investigated the occurrence of contaminants of emerging concern (CECs) in 67 freshwater, marine and terrestrial apex predators and in freshwater and marine prey, gathered from four European countries. Generic sample preparation protocols for the extraction of CECs with a broad range of physicochemical properties and the purification of the extracts were used. The analysis was performed utilizing liquid (LC) chromatography coupled to high resolution mass spectrometry (HRMS), while the acquired chromatograms were screened for the presence of more than 2,200 CECs through wide-scope target analysis. In total, 145 CECs were determined in the apex predator and their prey samples belonging in different categories, such as pharmaceuticals, plant protection products, per- and polyfluoroalkyl substances, their metabolites and transformation products. Higher concentration levels were measured in predators compared to prey, suggesting that biomagnification of chemicals through the food chain occurs. The compounds were prioritized for further regulatory risk assessment based on their frequency of detection and their concentration levels. The majority of the prioritized CECs were lipophilic, although the presence of more polar contaminants should not be neglected. This indicates that holistic analytical approaches are required to fully characterize the chemical universe of biota samples. Therefore, the present survey is an attempt to systematically investigate the presence of thousands of chemicals at a European level, aiming to use these data for better chemicals management and contribute to EU Zero Pollution Ambition.

Fate of 14C-labelled ionic organic chemicals in a water-sediment system and surface water.

The persistence assessment of organic chemicals is based on neutral reference substances. Therefore, our study aimed at investigating the influence of a chemical charge on the degradation of organic compounds in a water-sediment system (OECD 308) and surface water (OECD 309). We used radiolabelled 4-n-dodecylbenzenesulfonic acid sodium salt (14C-DS-, anionic), 4-n-dodecylbenzyltrimethylammonium chloride (14C-DA+, cationic) and 4-n-dodecylphenol (14C-DP, non-ionic) which are structurally similar except their charges. After 120 days of incubation in a water-sediment system, 68% (14C-DS-), 6% (14C-DA+) and 63% (14C-DP) of the applied radioactivity (AR) were mineralized. The formation of non-extractable residues (NER) after 120 days was highest for 14C-DA+ (33% AR), followed by 14C-DS- (19% AR) and 14C-DP (14% AR). Dissipation half-lives (DT50) at 12 °C decreased as follows: 14C-DA+ (346 days) ≫ 14C-DS- (47 days) > 14C-DP (30 days). After 60 days of incubation in surface water with suspended sediment, mineralization of 14C-DS-, 14C-DA+ and 14C-DP accounted for 63%, 7% and 58% AR, respectively. Highest NER formation was observed for 14C-DP (21% AR), followed by 14C-DA+ (14% AR) and 14C-DS- (9% AR). DT50 (12 °C) decreased as follows: 14C-DA+ (45 days) > 14C-DP (3 days) > 14C-DS- (2 days). We showed that a positive charge reduces the degradability of organic chemicals in both test systems. From a scientific point of view, simulation studies following OECD 309 should always be complimented by tests with high sorption capacity, e.g. OECD 308 and OECD 307 tests in order to assess the degradation of a compound, especially in case of cationic organic compounds.

Determination of 56 per- and polyfluoroalkyl substances in top predators and their prey from Northern Europe by LC-MS/MS.

Per- and polyfluoroalkyl substances (PFAS) are a group of emerging substances that have proved to be persistent and highly bioaccumulative. They are broadly used in various applications and are known for their long-distance migration and toxicity. In this study, 65 recent specimens of a terrestrial apex predator (Common buzzard), freshwater and marine apex predators (Eurasian otter, harbour porpoise, grey seal, harbour seal) and their potential prey (bream, roach, herring, eelpout) from northern Europe (United Kingdom, Germany, the Netherlands and Sweden) were analyzed for the presence of legacy and emerging PFAS, employing a highly sensitive liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method. 56 compounds from 14 classes were measured; 13 perfluoroalkyl carboxylic acids (PFCAs), 7 perfluoroalkyl sulphonic acids (PFSAs), 3 perfluorooctane sulfonamides (FOSAs), 4 perfluoroalkylphosphonic acids (PFAPAs), 3 perfluoroalkylphosphinic acids (PFPi's), 5 telomer alcohols (FTOHs), 2 mono-substituted polyfluorinated phosphate esters (PAPs), 2 di-substituted polyfluorinated phosphate esters (diPAPs), 6 saturated fluorotelomer acids (FTAS), 3 unsaturated fluorotelomer acids (FTUAs), 2 N-Alkyl perfluorooctane sulfonamidoethanols (FOSEs), 3 fluorotelomer sulphonic acids (FTSAs), 2 perfluoroether carboxylic acids (PFECAs) and 1 chlorinated perfluoroether sulphonic acid (Cl-PFESA). All samples were lyophilized before analysis, in order to enhance extraction efficiency, improve the precision and achieve lower detection limits. The analytes were extracted from the dry matrices through generic methods of extraction, using an accelerated solvent extraction (ASE), followed by clean-up through solid phase extraction (SPE). Method detection limits and method quantification limits ranged from 0.02 to 1.25 ng/g wet weight (ww) and from 0.05 to 3.79 ng/g (ww), respectively. Recovery ranged from 40 to 137%. Method precision ranged from 3 to 20 %RSD. The sum of PFAS concentration in apex predators livers ranged from 0.2 to 20.2 µg/g (ww), whereas in the fish species muscle tissues it ranged from 16 to 325 ng/g (ww). All analyzed specimens were primarily contaminated with PFOS, while the three PFPi's included in this study exhibited frequency of appearance (FoA) 100 %. C9 to C13 PFCAs were found at high concentrations in apex predator livers, while the overall PFAS levels in fish fillets also exceeded ecotoxicological thresholds. The findings of our study show a clear association between the PFAS concentrations in apex predators and the geographical origin of the specimens, with samples that were collected in urban and agricultural zones being highly contaminated compared to samples from pristine or semi-pristine areas. The high variety of PFAS and the different PFAS composition in the apex predators and their prey (AP&P) samples is alarming and strengthens the importance of PFAS monitoring across the food chain.

Fate and behavior of 14C-labelled ionic compounds in a soil simulation test.

The influence of an ionic functional group on the fate and behavior of chemicals in the environment has so far not been systematically investigated. This study, therefore, examines the following three substances with high structural similarity but differing charge: non-charged 4-n-dodecylphenol[phenylring-14C(U)] (14C-DP), negatively charged 4-n-dodecylbenzenesulfonicacid[phenylring-14C(U)] sodium salt (14C-DS-) and positively charged 4-n-dodecylbenzyltrimethylammonium chloride[phenylring-14C(U)] (14C-DA+). They were investigated in a soil simulation study according to the OECD 307 test guideline by measuring the distribution of the applied radioactivity (AR) among volatile, mineralized, extractable and non-extractable residues (NER) in one soil after 0, 1, 7, 14, 49, 84 and 124 days of incubation. Extractable portions of 14C were examined by means of radio-TLC and -HPLC analyses. Microbial activity of the soil incubated with and without 14C-DP, 14C-DS- and 14C-DA+ was determined measuring the reduction of dimethylsulfoxide (DMSO) over time. After 124 days of incubation highest mineralization could be observed for 14C-DS- (64.5% AR). Except CO2, no volatile residues were formed over time. Besides the parent compounds, polar (14C-DP, 14C-DS- and 14C-DA+) and nonpolar (14C-DA+) transformation products were detected. Highest amounts of 14C were extracted using methanol and were thus potentially bioavailable for soil microorganisms. Microbial activity was markedly higher in soil incubated with 14C-DP and 14C-DS- compared to 14C-DA+ or soil without any treatment. Half-lives (DT50 k2) at 18 °C were as follows: DA+ (61.8 days) > DS- (18.2 days) > DP (10.0 days). In case of the cationic compound and its transformation products we conclude that a higher sorption affinity to soil particles leads to reduced bioavailability for microorganisms and thus reduced mineralization resulting in a higher persistence compared to anionic and non-charged organic compounds in soil. The impact of our findings on the persistence assessment of chemicals when performing OECD guideline tests in soil, water-sediment and surface water is discussed.

Formation, classification and identification of non-extractable residues of 14C-labelled ionic compounds in soil.

The influence of an ionic functional group on the fate of chemicals in the environment, especially the formation of non-extractable residues (NER), has not been systematically investigated. Using 4-n-dodecylphenol[phenylring-14C(U)], 4-n-dodecylbenzenesulfonicacid[phenylring-14C(U)] sodiumsalt (14C-DS-) and 4-n-dodecylbenzyltrimethylammoniumchloride[phenylring-14C(U)] (14C-DA+) all with a high structural similarity, the formation, classification and identification of NER of negatively (14C-DS-), positively (14C-DA+) and uncharged (14C-DP) chemicals were investigated in a sterilized and non-sterilized soil. After 84 days of incubation in non-sterile soil, 40.6%, 21.7% and 33.5% of the applied radioactivity (AR) of 14C-DP, 14C-DS- and 14C-DA+, respectively, were converted to NER. In contrast, in sterile soil NER formation was markedly lower. The NER were further investigated with respect to sequestered, covalently bound and biogenic residues (i.e. NER types I, II, and III). Silylation of 14C-DP, 14C-DS- and 14C-DA+ derived NER released 3.0-23.2% AR, indicating that these were sequestered, whereas the residual NER (12.9-33.1% AR) was covalently bound to the soil. Analysis of extracts derived by silylation showed that 14C-DP, but neither 14C-DS- nor 14C-DA+, were released by silylation, suggesting that DP might be part of the sequestered NER. Acid hydrolysis of the NER containing soil and subsequent analysis of soil extracts for 14C-aminoacids indicated that 2.5-23.8% AR were biogenic residues. Most DP and DS- derived NER were biogenically or covalently bound, whereas DA+ predominantly forms sequestered NER in soil. From these results we propose that chemicals forming high amounts of NER should be investigated regarding types I-III NER because sequestered parent compounds should be considered in persistence assessments.

A correlation between the fate and non-extractable residue formation of 14C-metalaxyl and enzymatic activities in soil.

Extracellular, oxidative soil enzymes like monophenol oxidases and peroxidases play an important role in transformation of xenobiotics and the formation of organic matter in soil. Additionally, these enzymes may be involved in the formation of non-extractable residues (NERs) of xenobiotics during humification processes. To examine this correlation, the fate of the fungicide (14)C metalaxyl in soil samples from Ultuna (Sweden) was studied. Using different soil sterilization techniques, it was possible to differentiate between free, immobilized, and abiotic ("pseudoenzyme"-like) oxidative activities. A correlation between the formation of metalaxyl NER and soil organic matter content, biotic activities, as well as extracellular phenoloxidase and peroxidase activities in the bulk soil and its particle size fractions was determined. Extracellular soil-bound enzymes were involved in NER formation (up to 8% of applied radioactivity after 92 days) of the fungicide independently from the presence of living microbes and different distributions of the NER in the soil humic subfractions.