peer reviewed | Concentrations of organohalogenated contaminants (OHCs) can show significant temporal and spatial variation in the environment and wildlife. Most of the variation is due to changes in use and production, but environmental and biological factors may also contribute to the variation. Nestlings of top predators are exposed to maternally transferred OHCs in the egg and through their dietary intake after hatching. The present study investigated spatial and temporal variation of OHCs and the role of age and diet on these variations in plasma of Norwegian white-tailed eagle (Haliaeetus albicilla) nestlings. The nestlings were sampled at two locations, Smøla and Steigen, in 2015 and 2016. The age of the nestlings was recorded (range: 44 – 87 days old) and stable carbon and nitrogen isotopes (δ13C and δ15N) were applied as dietary proxies for carbon source and trophic position, respectively. In total, 14 polychlorinated biphenyls (PCBs, range: 0.82 – 59.05 ng/mL), 7 organochlorinated pesticides (OCPs, range: 0.89 – 52.19 ng/mL), 5 polybrominated diphenyl ethers (PBDEs, range: 0.03 – 2.64 ng/mL) and 8 perfluoroalkyl substances (PFASs, range: 4.58 – 52.94 ng/mL) were quantified in plasma samples from each location and year. The OHC concentrations, age and dietary proxies displayed temporal and spatial variations. The age of the nestlings was indicated as the most important predictor for OHC variation as the models displayed significantly decreasing plasma concentrations of PCBs, OCPs, and PBDEs with increasing age, while concentrations of PFASs were significantly increasing with age. Together with age, the variations in PCB, OCP and PBDE concentrations were also explained by δ13C and indicated decreasing concentrations with a more marine diet. Our findings emphasise age and diet as important factors to consider when investigating variations in plasma OHC concentrations in nestlings. © 2018 Elsevier Ltd | 230465

The Rodrigo de Freitas Lagoon (RFL - Rio de Janeiro, RJ, Brazil) is a highly polluted and eutrophic lacustrine system, which has been often used for the practice of aquatic sports, including during the 2016 Summer Olympic Games. This study proposes the evaluation of metal concentrations in surface sediments from the RFL before and after urban interventions performed for the 2016 Olympics, as well as their toxicity to the benthic amphipod Tiburonella viscana and embryos of the sea-urchin Echinometra lucunter. Metal concentrations determined in 2017 were significantly higher than those obtained in 2015 (especially Cu, Cd and Ni), suggesting that the interventions performed to fulfill the requirements of the Olympics increased metal contents in sediments. The sediments from the northern sector of the RFL were muddier, more organically enriched, exhibited higher metal concentrations and were more toxic to T. viscana when compared to the sediments collected in the southern sector. This fact is particularly important since the practice of sports, including during the 2016 Olympics, has been preferably performed in the northern sector. Metal distribution was strongly correlated with organic matter and mud contents. The toxicity to E. lucunter embryos was high for both northern and southern sediments; most of the samples led to 100% lack or abnormal embryonic development. The integration of physical, chemical and ecotoxicological data indicates that the mortality to T. viscana was correlated with metal contents, whereas the toxicity to E. lucunter was apparently related to the release of ammonia from the sediment to water column. Finally, high metal concentrations and the toxicity to aquatic organisms evidence the ecological risks to the biota from RFL.

Although effluent from municipal wastewater treatment plants (WWTPs) is a major stressor in receiving environments, relatively few studies have addressed how its discharge affects natural fish communities. Here, we assessed fish community composition over three years along a gradient of effluent exposure from two distinct WWTPs within an International Joint Commission Area of Concern on the Great Lakes (Hamilton Harbour, Canada). We found that fish communities changed with distance from both WWTPs, and were highly dissimilar between sites that were closest to and furthest from the wastewater outfall. Despite differences in the size and treatment technology of the WWTPs and receiving habitats downstream, we found that the sites nearest the outfalls had the highest fish abundances and contained a common set of signature fish species (i.e., round goby Neogobius melanostomus, green sunfish Lepomis cyanellus). Non-native and stress tolerant species were also more abundant near one of the studied WWTPs when compared to the reference site, and the number of young-of-the-year fish collected did not vary along the effluent exposure gradients. Overall, we show that fish are attracted to wastewater outfalls raising the possibility that these sites may act as an ecological trap.

Ubiquitous contamination of microplastics and arsenic in soil ecosystems can induce many health issues to nontarget soil organisms, and will also cause many potential threats to the gut bacterial communities of soil fauna. However, the changes in the gut bacterial communities of soil fauna after exposure to both microplastics and arsenic remain unknown. In this study, the toxicity and effects on the gut microbiota of earthworm Metaphire californica caused by the combined exposure of microplastics and arsenic were examined by using arsenic species analysis and high throughput sequencing of gut microbiota. Results showed that total arsenic and arsenic species in the earthworm gut and body tissues after exposure to combination of microplastics with arsenate (As(V)) were significantly different from that treated with As(V) alone. Microplastics lessened the accumulation of total arsenic and the transformation rate of As(V) to arsenite (As(III)). Microplastics alleviated the effect of arsenic on the gut microbiota possibly via adsorbing/binding As(V) and lowering arsenic bioavailability, thus prevented the reduction of As(V) and accumulation of total arsenic in the gut which resulted in a lower toxicity on the earthworm. The study broadens our understanding of the ecotoxicity of microplastics with other pollutants on the soil animals and on their gut microbiota.

The information acquired by high resolution quadrupole-time of flight mass spectrometry (QTOF-MS) allows target analysis as well as retrospective screening for the presence of suspect or unknown emerging pollutants which were not included in the target analysis. Targeted quantification of eight azole antifungal drugs in wastewater effluent as well as new and relatively simple retrospective suspect and non-target screening strategy for emerging pollutants using UHPLC-QTOF-MS is described in this work. More than 300 (parent compounds and transformation products) and 150 accurate masses were included in the retrospective suspect and non-target screening, respectively. Tentative identification of suspects and unknowns was based on accurate masses, peak intensity, blank subtraction, isotopic pattern (mSigma value), compound annotation using data bases such as KEGG and CHEBI, and fragmentation pattern interpretation. In the targeted analysis, clotrimazole, fluconazole, itraconazole, ketoconazole and posaconazole were detected in the effluent wastewater sample, fluconazole being with highest average concentration (302.38 ng L⁻¹). The retrospective screening resulted in the detection of 27 compounds that had not been included in the target analysis. The suspect compounds tentatively identified included atazanavir, citalopram, climbazole, bezafibrate estradiol, desmethylvenlafaxine, losartan carboxylic acid and cetirizine, of which citalopram, estradiol and cetirizine were confirmed using a standard. Carbamazepine, atrazine, efavirenz, lopinavir, fexofenadine and 5-methylbenzotriazole were among the compounds detected following the non-targeted screening approach, of which carbamazepine was confirmed using a standard. Given the detection of the target antifungals in the effluent, the findings are a call for a wide assessment of their occurrence in aquatic environments and their role in ecotoxicology as well as in selection of drug resistant fungi. The findings of this work further highlights the practical benefits obtained for the identification of a broader range of emerging pollutants in the environment when retrospective screening is applied to high resolution and high accuracy mass spectrometric data.

Microalgae are widely used as representative primary producers in ecotoxicology, while macrophytes are much less studied. Here we compared the bioavailability and cellular toxicity pathways of 2 h-exposure to 10−6 mol L−1 Cu in the macrophyte Elodea nuttallii and the green microalga Chlamydomonas reinhardtii.Uptake rate was similar but faster in the algae than in the macrophyte, while RNA-Sequencing revealed a similar number of regulated genes. Early-regulated genes were congruent with expected adverse outcome pathways for Cu with Gene Ontology terms including gene regulation, energy metabolism, transport, cell processes, stress, antioxidant metabolism and development. However, the gene regulation level was higher in E. nuttallii than in C. reinhardtii and several categories were more represented in the macrophyte than in the microalga. Moreover, several categories including oxidative pentose phosphate pathway (OPP), nitrate metabolism and metal handling were only found for E. nuttallii, whereas categories such as cell motility, polyamine metabolism, mitochondrial electron transport and tricarboxylic acid cycle (TCA) were unique to C. reinhardtii. These differences were attributed to morphological and metabolic differences and highlighted dissimilarities between a sessile and a mobile species. Our results highlight the efficiency of transcriptomics to assess early molecular responses in biota, and the importance of studying more aquatic plants for a better understanding on the impact and fate of environmental contaminants.

The widespread use of neonicotinoid insecticides is controversial due to their persistence in the environment and concerns the long-term consequences of their use. We present a simple, low-cost method for the sensitive and efficient extraction of three important neonicotinoids from soil with a detection limit <1 ng g−1 wet soil. We have validated this method by applying it to uncontaminated soil samples spiked with thiamethoxam, clothianidin and imidacloprid at environmentally concentrations. Absolute recoveries were >80% for thiamethoxam, clothianidin and imidacloprid. We also applied the method to soil samples collected from maize fields in New Zealand's North Island and found imidacloprid in 43 out of 45 samples and clothianidin in every one. Mean imidacloprid concentrations varied from 0.5 to 9.4 ng g−1 (wet weight) and clothianidin from 2.1 to 26.7 ng g−1 (wet weight). Imidacloprid concentrations exceed the New Zealand Environmental Protection Agency's Environmental Exposure Limit of 1 ng g−1 (dry weight) at eight of the nine sites sampled. These results are also remarkable because we have detected multiple neonicotinoid residues at every site. Imidacloprid residues appear to persist at significant concentrations at five of our sites from an application at least two years previous. This is only the third study to report the presence of neonicotinoid residues in NZ's environment and the first to show that those residues are persistent in the environment at nominally hazardous concentrations.

The micronucleus (MN) test of the human buccal mucosa was developed more than 30 years ago, although this technique has only recently been applied to wild mammals. This paper presents a pioneering study in the genotoxicological evaluation of the exfoliated cells of the buccal mucosa of bats. The assay was applied to two insectivorous bat species (Noctilio albiventris and Pteronotus parnellii) sampled in riparian corridors located in the city of Palmas (capital of the Brazilian state of Tocantins), with the results being compared with those obtained for a third insectivorous species (Nyctinomops laticaudatus), which has established a colony under a road bridge in the same region. This colony represents one of the largest molossidae populations ever recorded in Brazil. A significantly higher frequency of micronuclei was recorded in this colony, as well as a number of other nuclear abnormalities, including binucleated cells, cells with condensed chromatin and karyolysis, in comparison with the bats from the riparian corridors, indicating that the bats from the bridge colony are more susceptible to genotoxic damage. Thus, it is demonstrated the importance of the biomarker (MN) for use in wild animals and allows to conclude that colony bats are more susceptible to genotoxic damages.

Microcystis aeruginosa is one of the main species of cyanobacteria that causes water blooms. M. aeruginosa can release into the water several types of microcystins (MCs), which are harmful to aquatic organisms and even humans. However, few studies have investigated the hepatotoxicity of M. aeruginosa itself in zebrafish in environments that simulate natural aquatic systems. The objective of this study was to evaluate the hepatotoxicity of M. aeruginosa in adult zebrafish (Danio rerio) after short-term (96 h) exposure and to elucidate the potential underlying mechanisms. Distinct histological changes in the liver, such as enlargement of the peripheral nuclei and sinusoids and the appearance of fibroblasts, were observed in zebrafish grown in M. aeruginosa culture. In addition, antioxidant enzyme activity was activated and protein phosphatase (PP) activity was significantly decreased with increasing microalgal density. A proteomic analysis revealed alterations in a number of protein pathways, including ribosome translation, immune response, energy metabolism and oxidative phosphorylation pathways. Western blot and real-time PCR analyses confirmed the results of the proteomic analysis. All results indicated that M. aeruginosa could disrupt hepatic functions in adult zebrafish, thus highlighting the necessity of ecotoxicity assessments for M. aeruginosa at environmentally relevant densities.

Microplastics (plastic particles <5 mm) are a contaminant of increasing ecotoxicological concern in aquatic environments, as well as for human health. Although microplastic pollution is widespread across the land, water, and air, these environments are commonly considered independently; however, in reality are closely linked. This study aims to review the scientific literature related microplastic research in different environmental compartments and to identify the research gaps for the assessment of future research priorities. Over 200 papers involving microplastic pollution, published between 2006 and 2018, are identified in the Web of Science database. The original research articles in ‘Environmental Sciences’, ‘Marine/Freshwater Biology’, ‘Toxicology’, ‘Multidisciplinary Sciences’, ‘Environmental Studies’, ‘Oceanography’, ‘Limnology’ and ‘Ecology’ categories of Web of Science are selected to investigate microplastic research in seas, estuaries, rivers, lakes, soil and atmosphere. The papers identified for seas, estuaries, rivers and lakes are further classified according to (i) occurrence and characterization (ii) uptake by and effects in organisms, and (iii) fate and transport issues. The results reveal that whilst marine microplastics have received substantial scientific research, the extent of microplastic pollution in continental environments, such as rivers, lakes, soil and air, and environmental interactions, remains poorly understood.