Found 2670 publications. Showing page 53 of 267:
This study investigated concentrations of phthalates (diesters of phthalic acids) in blubber/adipose tissue of blue whales (Balaenoptera musculus), fin whales (Balaenoptera physalus), bowhead whales (Balaena mysticetus) and polar bears (Ursus maritimus) sampled in the Svalbard Archipelago (extending westward in the case of bowhead whales). Additionally, total concentrations (free and conjugated forms) of eight phthalate monoester metabolites were analysed in plasma of polar bears. Bis(2-ethylhexyl) phthalate (DEHP) was the only phthalate quantified among the 12 phthalates investigated. This compound was present in 6/7 fin whale samples, 4/7 blue whale samples, 2/5 bowhead whale samples and 1/12 polar bear samples. DEHP concentrations ranged from <20–398 ng/g wet weight. Phthalate metabolites, mono-n-butyl phthalate and monoisobutyl phthalate, were found in low concentrations (<1.2 ng/mL) in some of the polar bear samples. In vitro reporter gene assays were used to assess transcriptional activity of fin whale peroxisome proliferator-activated receptor gamma (PPARG), glucocorticoid receptor (GR) and the thyroid hormone receptor beta (THRB) by DEHP and diisononyl phthalate (DiNP). Due to the high degree of similarity of the ligand binding domain in the THRB and PPARG among whales, polar bears and humans, the transactivation results also apply for these species. DEHP showed both agonistic and antagonistic effects towards whale THRB at considerably higher concentrations than measured in the study animals; DiNP was a weak agonist of whale THRB. No significant agonistic or antagonistic effects were detected for DEHP or DiNP for whale PPARG, whereas DEHP and DiNP decreased basal luciferase activity mediated by whale GR at several test concentrations. In conclusion, DEHP was detected in the blubber of marine mammals from the Norwegian Arctic and it appears to have potential to modulate the transcriptional activity of whale THRB, but current DEHP concentrations do not modulate the function of the studied nuclear receptors in adipose tissue of blue whales, fin whales, bowhead whales or polar bears sampled from the Norwegian Arctic.
2021
High levels of organochlorines (OCs) have been measured in arctic char (Salvelinus alpinus) from Lake Ellasjøen on Bjørnøya, Norway (74.30°N, 19.0°E). In a nearby lake, Laksvatn, the OC-levels in arctic char were low. A previous study has shown that char from Ellasjøen had significantly higher levels of DNA double strand breaks (DSBs) than char from Lake Laksvatn. Even though there is increasing evidence of the genotoxic effects of OCs, little is known about the effects of OCs on the DNA repair system. The aim of the present study was to determine if the two main DNA DSB repair mechanisms, homologous recombination (HR) and non-homologous end-joining (NHEJ), are affected by the higher OC and DSB level in char from Ellasjøen. This was analysed by comparing the transcript level of 11 genes involved in DNA DSB repair in char liver samples from Ellasjøen (n = 9) with char from Laksvatn (n = 12). Six of the investigated genes were significantly upregulated in char from Ellasjøen. As the expression of DNA DSB repair genes was increased in the contaminant-exposed char, it is likely that the DNA DSB repair capacity is induced in these individuals. This induction was positively correlated with the DNA DSB and negatively correlated with one or several OCs for four of these genes. However, the strongest predictor variable for DNA repair genes was habitat, indicating genetic differences in repair capacity between populations. As char from Ellasjøen still had significantly higher levels of DSBs compared to char from Laksvatn, it is possible that chronic exposure to OCs and continued production of DSB has caused selective pressure within the population for fixation of adaptive alleles. It is also possible that DSB production was exceeding the repair capacity given the prevailing conditions, or that the OC or DSB level was above the threshold value of inhibition of the DNA repair system resulting in the rate of DNA damage exceeding the rate of repair.
2021
In birds, maternal transfer is a major exposure route for several contaminants, including poly- and perfluoroalkyl substances (PFAS). Little is known, however, about the extent of the transfer of the different PFAS compounds to the eggs, especially for alternative fluorinated compounds. In the present study, we measured legacy and emerging PFAS, including Gen-X, ADONA, and F-53B, in the plasma of prelaying black-legged kittiwake females breeding in Svalbard and the yolk of their eggs. We aimed to (1) describe the contaminant levels and patterns in both females and eggs, and (2) investigate the maternal transfer, that is, biological variables and the relationship between the females and their eggs for each compound. Contamination of both females and eggs were dominated by linPFOS then PFUnA or PFTriA. We notably found 7:3 fluorotelomer carboxylic acid─a precursor of long-chain carboxylates─in 84% of the egg yolks, and provide the first documented finding of ADONA in wildlife. Emerging compounds were all below the detection limit in female plasma. There was a linear association between females and eggs for most of the PFAS. Analyses of maternal transfer ratios in females and eggs suggest that the transfer is increasing with PFAS carbon chain length, therefore the longest chain perfluoroalkyl carboxylic acids (PFCAs) were preferentially transferred to the eggs. The mean ∑PFAS in the second-laid eggs was 73% of that in the first-laid eggs. Additional effort on assessing the outcome of maternal transfers on avian development physiology is essential, especially for PFCAs and emerging fluorinated compounds which are under-represented in experimental studies.
black-legged kittiwake Rissa tridactyla top predator Svalbard PFAS emerging contaminants
2021
The historical (1835–2020) dry deposition of major air pollutants (SO2, NOx, O3 and PM2.5) in the urban background in Oslo, Norway, in a situation that could represent the building facades, was approximated from reported fuel combustion, emission factors, air concentrations since 1960, and dry deposition velocities. The annual accumulated dry deposition (and thus not considering the removal processes) of the pollutants, together, was found to have varied from about 2.3 to 27 g m−2, with the maximum in the 1960s caused by high SO2 emissions from the combustion of fuel oils, and with 1.6 kg m−2 having deposited over all the years. The deposition of PM2.5 was found to have dominated from 1835, have increased to a maximum in 1875 and then slowly decreased. The SO2 deposition decreased to a low value around 1990. The NOx deposition was also at its highest in the 1960s to about 1970, it became the largest from the 1980s, and then showed a clear decrease from about 2010. The O3 deposition was lower in the years of the maximum total and NOx deposition. The dry deposition of O3 and NOx were found to be about similar in 2020, more than two times that of PM2.5 and more than four times that of SO2. The trends of the NOx emissions were found to reflect the relative (1975) and absolute (∼2000) turning points of the environmental Kuznets curves (EKC) that has been suggested for Norway, whereas the trend of the SO2 emissions seems to have “shortcut” this development by the strong regulations in the emissions from 1970 that lead to near simultaneous relative and absolute reductions. The gradual decrease of the PM2.5 emissions from about 1945 seems to correspond with the decrease in combustion energy intensity in the economy as wood was substituted with more energy efficient fuels and then with the continued reduction in the wood burning.
2021
Hemispheric black carbon increase after the 13th-century Māori arrival in New Zealand
New Zealand was among the last habitable places on earth to be colonized by humans. Charcoal records indicate that wildfires were rare prior to colonization and widespread following the 13th- to 14th-century Māori settlement, but the precise timing and magnitude of associated biomass-burning emissions are unknown, as are effects on light-absorbing black carbon aerosol concentrations over the pristine Southern Ocean and Antarctica. Here we used an array of well-dated Antarctic ice-core records to show that while black carbon deposition rates were stable over continental Antarctica during the past two millennia, they were approximately threefold higher over the northern Antarctic Peninsula during the past 700 years. Aerosol modelling demonstrates that the observed deposition could result only from increased emissions poleward of 40° S—implicating fires in Tasmania, New Zealand and Patagonia—but only New Zealand palaeofire records indicate coincident increases. Rapid deposition increases started in 1297 (±30 s.d.) in the northern Antarctic Peninsula, consistent with the late 13th-century Māori settlement and New Zealand black carbon emissions of 36 (±21 2 s.d.) Gg y−1 during peak deposition in the 16th century. While charcoal and pollen records suggest earlier, climate-modulated burning in Tasmania and southern Patagonia, deposition in Antarctica shows that black carbon emissions from burning in New Zealand dwarfed other preindustrial emissions in these regions during the past 2,000 years, providing clear evidence of large-scale environmental effects associated with early human activities across the remote Southern Hemisphere.
2021
Atmospheric corrosion due to amine emissions from carbon capture plants
The atmospheric corrosion due to pure amines emitted from carbon capture plants was investigated. Amine exposure was found to initially inhibit the corrosion of steel, by its film formation and alkalinity, but reduce corrosion product layers and lead to freezing point depression, which could in turn increase the corrosion. Very high amine doses were observed to dissolve the metal without the establishing of a corrosion layer. These effects seem much more pronounced on copper than on steel. Climate and air quality variations affect the steel corrosion much more than the expected maximum amine deposition from carbon capture plant emissions.
2021
A strategy towards the generation of testable adverse outcome pathways for nanomaterials
Manufactured nanomaterials (NMs) are increasingly used in a wide range of industrial applications leading to a constant increase in the market size of nano-enabled products. The increased production and use of NMs are constantly raising concerns among different stakeholder groups with regard to their effects on human and environmental health. Currently, nanosafety hazard assessment is still widely performed using in vivo (animal) models, however the development of robust and regulatory relevant strategies is required to prioritize and/or reduce animal testing. Adverse outcome pathways (AOPs) are a structured representation of biological events that start from a molecular initiating event (MIE) leading to an adverse outcome (AO) through a series of key events (KEs). The AOP framework offers great advancement to risk assessment and regulatory safety assessments. While AOPs for chemicals have been more frequently reported, AOPs collection for NMs is narrow. By using existing AOPs, we aimed to generate simple and testable strategies to predict if a given NM has the potential to induce a MIE leading to an AO through a series of KEs. Firstly, we identified potential MIEs or initial KEs reported for NMs in the literature. Then, we searched the identified MIE or initial KEs as keywords in the AOP-Wiki to find associated AOPs. Finally, using two case studies, we demonstrated here how in vitro strategies can be used for testing the identified MIE/KEs.
2021
Brominated Flame Retardants in Antarctic Air in the Vicinity of Two All-Year Research Stations
Continuous atmospheric sampling was conducted between 2010–2015 at Casey station in Wilkes Land, Antarctica, and throughout 2013 at Troll Station in Dronning Maud Land, Antarctica. Sample extracts were analyzed for polybrominated diphenyl ethers (PBDEs), and the naturally converted brominated compound, 2,4,6-Tribromoanisole, to explore regional profiles. This represents the first report of seasonal resolution of PBDEs in the Antarctic atmosphere, and we describe conspicuous differences in the ambient atmospheric concentrations of brominated compounds observed between the two stations. Notably, levels of BDE-47 detected at Troll station were higher than those previously detected in the Antarctic or Southern Ocean region, with a maximum concentration of 7800 fg/m3. Elevated levels of penta-formulation PBDE congeners at Troll coincided with local building activities and subsided in the months following completion of activities. The latter provides important information for managers of National Antarctic Programs for preventing the release of persistent, bioaccumulative, and toxic substances in Antarctica.
2021
The 11 year solar cycle UV irradiance effect and its dependency on the Pacific Decadal Oscillation
The stratospheric, tropospheric and surface impacts from the 11 year ultraviolet solar spectral irradiance (SSI) variability have been extensively studied using climate models and observations. Here, we demonstrate using idealized model simulations that the Pacific Decadal Oscillation (PDO), which has been shown to impact the tropospheric and stratospheric circulation from sub-decadal to multi-decadal timescales, strongly modulates the solar-induced atmospheric response. To this end, we use a high-top version of the coupled ocean–atmosphere Norwegian Climate Prediction Model forced by the SSI dataset recommended for Coupled Model Intercomparison Project 6. We perform a 24-member ensemble experiment over the solar cycle 23 in an idealized framework. To assess the PDO modulation of the solar signal, we divide the model data into the two PDO phases, PDO+ and PDO−, for each solar (maximum or minimum) phase. By compositing and combining the four categories, we hence determine the component of the solar signal that is independent of the PDO and the modulation of the solar signal by the PDO, along with the solar signal in each PDO phase. Reciprocally, we determine the PDO effect in each solar phase. Our results show that the intensification of the polar vortex under solar maximum is much stronger in the PDO− phase. This signal is transferred into the troposphere, where we find a correspondingly stronger polar jet and weaker Aleutian Low. We further show that the amplification of the solar signal by the PDO− phase is driven by anomalous meridional advection of solar-induced temperature anomalies over northern North America and the North Pacific, which contributes to a decreased meridional eddy heat flux and hence to a decreased vertical planetary wave flux into the stratosphere.
2021