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 (Buteo buteo) 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

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

Studien zum Einfluss einer chemischen Ladung auf Sorption, Schicksal und Bildung nicht-extrahierbarer Rückstände organischer Chemikalien im Boden

In the present study we investigated the influence of an ionic functional group on the sorption, fate and formation of non-extractable residues of organic compounds in soil. Using uncharged 4-n-dodecylphenol[phenyl ring-14C(U)] (14C-DP), negatively charged 4-n-dodecylbenzenesulfonic acid[phenyl ring-14C(U)] sodium salt (14C-DS-) and positively charged 4-n-dodecylbenzyltrimethylammonium chloride[phenyl ring-14C(U)] (14CDA+) with high structural similarity, we performed sorption tests according to OECD 106 (Adsorption - Desorption using a Batch-Equilibrium Method) and simulation tests in soil according to OECD 307 (Aerobic and Anaerobic Transformation in Soil) with LUFA soil 5M. In the sorption tests equilibrium for adsorption and desorption of 14C-DA+ was reached after 15 and 1680 min and for 14C-DP and 14C-DS- after 240 min, respectively. During the sorption test, DP was abiotically degraded to more polar transformation products. Partitioning coefficients were therefore determined according to the amounts of adsorbed and desorbed DP detected by TLC-Analysis. Sorption kinetic for DS- was linear and the partitioning coefficients for adsorption and desorption amounted to logK=2.68 and logK =1.78. Cooperative adsorption of DP und DA+ was obviously higher (logK>3.30) compared to 14C-DS- and is considered irreversible (logK 3.0) and deviate from calculated logKoc in case of the ionic chemicals. Considering the structural similarity it could be shown that a positive charge lead to an increased sorption of organic chemicals on soil. Aim of the simulation test was to investigate the fate of 14C-DP, 14C-DS- und 14C-DA+ in sterile and non-sterile soil. After application of the test substances with 1 mg/kg to sterilized and non-sterilized soil and incubation for 0, 1, 7, 14, 49, 84 and 124 days, samples were sequentially extracted. Distribution of the applied radioactivity (AR) among volatile, mineralized, extractable and non-extractable residues (NER) for 14C-DP, 14C-DS- und 14C-DA+ were investigated. Extractable portions of 14C were examined by means of TLC, HPLC and LC-MS/MS analyses. After 124 days of incubation highest mineralization could be observed for 14C-DS- (64.5% AR), followed by 14C-DP (44.0% AR) and 14C-DA+ (37.8% AR) whereas formation of 14CO2 in sterile soil was neglectable. In case of 14C-DP und 14C-DS- the rate of mineralization and the microbial activity (DMSO reduction rate) in non-sterilized soil simultaneous increased from day 0 until day 14. For 14C-DA+ the mineralization and DMSO reduction rate were constantly low over time. Extractable radioactivity for 4C-DA+ amounted to 18.0% AR, but only low amounts of 14C-DP und 14C-DS- were extractable form the soil (2.7-4.7% AR) at the end of the test. Besides 14C-DP, 14C-DS- and 14C-DA+ polar and nonpolar (14C-DA+) transformation products were detected in the extracts over time. Highest amounts of 14C-DP, 14C-DS- and 14C-DA+ were potentially bioavailable in soil. In the calcium chloride extracts only transformation products were detected. Half-life (DT50) decrease in the following manner: DA+(61.70 days)>DS-(18.20 days)>DP(9.96 days). The findings suggest that a negative and positive charge increases the DT50 of organic chemicals in soil. Highest amounts of NER at the end of the tests were observed for 14C-DP (45.4% AR) followed by 14C-DA+ (34.2% AR) and 14C-DS- (23.1% AR). Considerable amounts of NER of 14C-DA+ (16.0% AR) were formed under sterile soil conditions. NER at day 7 and 84 were further investigated with respect to sequestered, covalently bound and biogenic residues (NER types I, II, and III). Silylation of 14C-DP, 14C-DS- and 14C-DA+ derived NER after 7 and 84 days of incubation released 3.0-23.2% AR, indicating that these were strongly sorbed or physically entrapped (type I NER) in the soil. The reminder of the residues (12.9-33.1% AR) were covalently bound (type II NER) to the soil. Analysis of extracts derived by silylation shows that 14C-DP (2.3% AR), but neither 14C-DS- nor 14C-DA+ were released by the silylation procedure. This suggests that only in case of 14C-DP, the parent substance was part of type I NER, which is considered reversibly bound to soil. Acid hydrolysis of the 14C-DP, 14C-DS- and 14C-DA+ NER containing soil after 7 and 84 days of incubation and subsequent analysis of soil extracts regarding 14C-aminoacids (14C-AA) indicates that 2.5-23.8% AR are biogenically formed residues (type III NER) in soil. Most DP and DS- derived NER were biogenically or covalently bound, whereas DA+ predominantly forms sequestered NER in soil. After re-incubation of the NER containing soil of 14C-DP, 14C-DS- und 14C-DA+ after 7 and 84 days with nonsterilized soil for 54 days, remobilisation (sum of volatile, mineralised and extractable residues) amounted to 7.2-19.1% AR; however, the highest amounts still remained nonextractable in soil (16.4-31.2% AR). With regard to the results it is recommended to use an experimentally determined logKd instead of calculated/experimental logKoc values for the assessment of the adsorption of ionic chemicals in soil in frame of persistence assessment. Furthermore, chemicals with an obviously high NER formation should be investigated according to sequestered (type I), covalently bound (type II) and biogenic (type III) NER. The formation of type I NER should be taken into account in the persistence assessment, if the parent substance has been analytically determined in this fraction. In this case, the sequestered amount of parent molecule should be included in the calculation of the DT50. In case that analytical investigations of type I NER regarding the parent molecule were technically not feasible, the DT50 has to be calculated considering the total amount of sequestered (type I) NER in accordance with the precautionary principle

Systemic Lipopolysaccharide Challenge Induces Inflammatory Changes in Rat Dorsal Root Ganglia: An Ex Vivo Study

Inflammatory processes within the peripheral nervous system (PNS) are associated with symptoms of hyperalgesia and allodynia. Pro-inflammatory mediators, such as cytokines or prostaglandins, modulate the excitability of nociceptive neurons, called peripheral sensitization. Here, we aimed to examine if previously reported effects of in vitro stimulation with lipopolysaccharide (LPS) on primary cell cultures of dorsal root ganglia (DRG) reflect changes in a model of LPS-induced systemic inflammation in vivo. Male rats were intraperitoneally injected with LPS (100 µg/kg) or saline. Effects of systemic inflammation on expression of inflammatory mediators, neuronal Ca2+ responses, and activation of inflammatory transcription factors in DRG were assessed. Systemic inflammation was accompanied by an enhanced expression of pro-inflammatory cytokines and cyclooxygenase-2 in lumbar DRG. In DRG primary cultures obtained from LPS-treated rats enhanced neuronal capsaicin-responses were detectable. Moreover, we found an increased activation of inflammatory transcription factors in cultured macrophages and neurons after an in vivo LPS challenge compared to saline controls. Overall, our study emphasizes the role of inflammatory processes in the PNS that may be involved in sickness-behavior-associated hyperalgesia induced by systemic LPS treatment. Moreover, we present DRG primary cultures as tools to study inflammatory processes on a cellular level, not only in vitro but also ex vivo

α-Synuclein in Parkinson's disease: causal or bystander?

Parkinson’s disease (PD) comprises a spectrum of disorders with differing subtypes, the vast majority of which share Lewy bodies (LB) as a characteristic pathological hallmark. The process(es) underlying LB generation and its causal trigger molecules are not yet fully understood. α-Synuclein (α-syn) is a major component of LB and SNCA gene missense mutations or duplications/triplications are causal for rare hereditary forms of PD. As typical sporadic PD is associated with LB pathology, a factor of major importance is the study of the α-syn protein and its pathology. α-Syn pathology is, however, also evident in multiple system atrophy (MSA) and Lewy body disease (LBD), making it non-specific for PD. In addition, there is an overlap of these α-synucleinopathies with other protein-misfolding diseases. It has been proven that α-syn, phosphorylated tau protein (pτ), amyloid beta (Aβ) and other proteins show synergistic effects in the underlying pathogenic mechanisms. Multiple cell death mechanisms can induce pathological protein-cascades, but this can also be a reverse process. This holds true for the early phases of the disease process and especially for the progression of PD. In conclusion, while rare SNCA gene mutations are causal for a minority of familial PD patients, in sporadic PD (where common SNCA polymorphisms are the most consistent genetic risk factor across populations worldwide, accounting for 95% of PD patients) α-syn pathology is an important feature. Conversely, with regard to the etiopathogenesis of α-synucleinopathies PD, MSA and LBD, α-syn is rather a bystander contributing to multiple neurodegenerative processes, which overlap in their composition and individual strength. Therapeutic developments aiming to impact on α-syn pathology should take this fact into consideration

Using environmental monitoring data from apex predators for chemicals management: towards better use of monitoring data from apex predators in support of prioritisation and risk assessment of chemicals in Europe

International audienceA large number of apex predator samples are available in European research collections, environmental specimen banks and natural history museums that could be used in chemical monitoring and regulation. Apex predators bioaccumulate pollutants and integrate contaminant exposure over large spatial and temporal scales, thus providing key information for risk assessments. Still, present assessment practices under the different European chemical legislations hardly use existing chemical monitoring data from top predators. Reasons include the lack of user-specific guidance and the fragmentation of data across time and space. The European LIFE APEX project used existing sample collections and applied state-of-the-art target and non-target screening methods, resulting in the detection of > 4,560 pollutants including legacy compounds. We recommend establishing infrastructures that include apex predators as an early warning system in Europe. Chemical data of apex species from freshwater, marine and terrestrial compartments should become an essential component in future chemical assessment and management across regulations, with the purpose to (1) validate registration data with ‘real world’ measurements and evaluate the predictability of current models; (2) identify and prioritise hazardous chemicals for further assessment; (3) use data on food web magnification as one line of evidence to assess biomagnification; (4) determine the presence of (bio)transformations products and typical chemical mixtures, and (5) evaluate the effectiveness of risk management measures by trend analysis. We highlight the achievements of LIFE APEX with regard to novel trend and mixture analysis tools and prioritisation schemes. The proposed advancements complement current premarketing regulatory assessments and will allow the detection of contaminants of emerging concern at an early stage, trigger risk management measures and evaluations of their effects with the ultimate goal to protect humans and the environment. This is the second policy brief of the LIFE APEX project