The hydrocarbon phenanthrene is an organic compound commonly found in the environment. In aquatic ecosystems, it is highly toxic to organisms, although little is known about its effects on sediment-dwelling organisms. The purpose of this study was to evaluate phenanthrene effects on biochemical, histological, and ontogenetic levels in larvae of the sediment-dwelling invertebrate Chironomus sancticaroli at acute and chronic exposure. Lethal concentrations were estimated and toxicity (acute-96 h and chronic- 8 d) tests were performed at phenanthrene concentrations from 0.12 to 1.2 mg L⁻¹. At acute and chronic exposure, we evaluated acetylcholinesterase (AChE), alpha esterase (EST-α), and beta esterase (EST-β) activities as well as histological alterations. In the assays with chronic exposure, effects on larval development were estimated using antennae length (instar estimative) and body length (growth estimative). The EST-α showed a significantly increased activity after 48 h at acute exposure to high concentrations of phenanthrene, while EST-β activity was increased after 48 and 72 h at acute exposure at higher concentrations and at 0.12 mg L⁻¹ at chronic exposure. At acute exposure, the midgut showed alterations such as brush border disruption, gastric caeca regression, and lumen area reduction; the fat body showed nuclear alteration in the trophocytes, while the Malpighian tubules showed brush border reduction and the salivary glands were subject to cytoplasm vacuolation. At chronic exposure, the same alterations were observed, in addition to vacuolar coalescence in the trophocytes of the fat body. Regarding larval development, a reduction of body length was observed with increasing phenanthrene concentrations. Similarly, molting was delayed; in the control group, all larvae were in the fourth instar, while at higher phenanthrene concentrations, larvae were predominantly in the third instar. Phenanthrene had toxic effects on this chironomid, indicating risks for natural populations.

With increasing demand for recycled wastewater for irrigation purposes, there is a need to evaluate the potential for manufactured nanomaterials in waste water to impact crop production and agroecosystems. Copper oxide nanoparticles (CuO NPs) have previously been shown to negatively impact the growth of duckweed (Landoltia punctata) a model aquatic plant consumed by water fowl and widely found in agricultural runoff ditches in temperate climates. However, prior studies involving CuO NP toxicity to duckweed have focused on systems without the presence of dissolved organic matter (DOM). In the current study, duckweed growth inhibition was shown to be a function of aqueous Cu²⁺ concentration. Growth inhibition was greatest from aqueous CuCl₂ and, for particles, increased with decreasing CuO particle size. The dissolution of CuO NPs in ½ Hoagland's solution was measured to increase with decreasing particle size and in the presence of Suwannee river humic and fulvic acids (HA; FA). However, the current results suggest that HA, and to a lesser extent, FA, decrease the toxicity of both CuO NPs and free ionized Cu to duckweed, likely by inhibiting Cu availability through Cu-DOM complex formation. Such results are consistent with changes to Cu speciation as predicted by speciation modeling software and suggest that DOM changes Cu speciation and therefore toxicity in natural systems.

Due to its dependence on fossil fuel combustion, emissions from the marine transport sector can significantly contribute to air pollution. This work aims to evaluate the impact of maritime transport emissions on air quality in Portugal using a numerical air quality modelling approach, with high-resolution emission data. Emissions from the European TNO inventory were compiled and pre-processed at hourly and high spatial (∼3 × 3 km²) resolutions. Scenarios with and without these maritime emissions were then simulated with the WRF-CHIMERE modelling system, extensively tested and validated for Portugal domain, in order to evaluate their impact on air quality. A simulation was performed for one year (2016) and the resulting differences were analysed in terms of spatial distribution, time series and deltas. The main deltas for NO₂ and PM10 are located over international shipping routes and major ports, while O₃ concentrations are impacted in a larger area. The modelling results also indicate that shipping emissions are responsible for deltas in the concentration of NO₂ higher than 20% over specific urban areas located in the west coast of Portugal, and less than 5% for PM10. For O₃ the relative contribution is low (around 2%) but this contribution is also observed at locations more than 50 km from the coast.

The Arctic is a unique and fragile ecosystem that needs to be preserved and protected. Despite its remoteness, plastic pollution has been documented in this region. In the coming years, it is likely to worsen since, with climate changes and the opening of new shipping routes, the human presence is going to increase in the whole area. Here, we investigated the presence of microplastics (MPs) in sub-surface water and in two mid-trophic level Arctic fishes collected off Northeast Greenland: the demersal bigeye sculpin, Triglops nybelini, and the pelagic polar cod, Boreogadus saida. Plastics debris were found in the water samples at a concentration of 2.4 items/m³ ±0.8 SD which is higher than in most seas at lower latitudes. Both fish species had eaten MPs with different proportion among the species, 34% for T. nybelini (n = 71) and 18% for B. saida (n = 85). The significant difference in the occurrence of MPs between the two species is likely a consequence of their feeding behavior and habitat. Polyethylene was the main plastic polymer for water samples (41%, n = 17) and polyester (34%, n = 156) for fish samples as analyzed by Fourier Transformed Infrared (FT-IR) spectroscopy. Our data underscore that the Arctic regions are turning into a hotspot for plastic pollution, and this calls urgently for precautionary measures.

With the ever-increasing amounts of oil sands process-affected water (OSPW) accumulating from Canada's oil sands operations, its eventual release must be considered. As OSPW has been found to be both acutely and chronically toxic to aquatic organisms, remediation processes must be developed to lower its toxicity. Ozone treatment is currently being studied as a tool to facilitate the removal of organic constituents associated with toxicity. Biomarkers (e.g. gene expression) are commonly used when studying the effects of environmental contaminants, however, they are not always indicative of adverse effects at the whole organism level. In this study, we assessed the effects of OSPW exposure on developing zebrafish by linking gene expression to relevant cellular and whole organism level endpoints. We also investigated whether or not ozone treatment decreased biomarkers and any associated toxicity observed from OSPW exposure. The concentrations of classical naphthenic acids in the raw and ozonated OSPW used in this study were 16.9 mg/L and 0.6 mg/L, respectively. Ozone treatment reduced the total amount of naphthenic acids (NAs) in the OSPW sample by 92%. We found that exposure to both raw and ozonated OSPW had no effect on the survival of zebrafish embryos. The expression levels of biotransformation genes CYP1A and CYP1B were induced by raw OSPW exposure, with CYP1B being more highly expressed than CYP1A. In contrast, ozonated OSPW exposure did not increase the expression of CYP1A and only slightly induced CYP1B. A decrease in cardiac development and function genes (NKX2.5 and APT2a2a) was not associates with large changes in heart rate, arrhythmia or heart size. We did not find any indications of craniofacial abnormalities or of increased occurrence of apoptotic cells. Overall, our study found that OSPW was not overtly toxic to zebrafish embryos.

This study implements a two-box model coupled with ultrafine particle (UFP) multicomponent microphysics for a compartmentalised street canyon. Canyon compartmentalisation can be described parsimoniously by three parameters relating to the features of the canyon and the atmospheric state outside the canyon, i.e. the heterogeneity coefficient, the vortex-to-vortex exchange velocity, and the box height ratio. The quasi-steady solutions for the two compartments represent a balance among emissions, microphysical aerosol dynamics (i.e. evaporation/condensation of semi-volatiles, SVOCs), and exchange processes, none of which is negligible. This coupled two-box model can capture significant contrasts in UFP number concentrations and a measure of the volatility of the multi-SVOC-particles in the lower and upper canyon. Modelled ground-level UFP number concentrations vary across nucleation, Aitken, and accumulation particle modes as well-defined monotonic functions of canyon compartmentalisation parameters. Compared with the two-box model, a classic one-box model (without canyon compartmentalisation) leads to underestimation of UFP number concentrations by several tens of percent typically. By quantifying the effects of canyon compartmentalisation, this study provides a framework for understanding how canyon geometry and the presence of street trees, street furniture, and architectural features interact with the large-scale atmospheric flow to determine ground-level pollutant concentrations.

Prenatal disinfection by-products (DBPs) exposure is linked with adverse birth outcomes. Genetic susceptibility to DBP metabolism may modify the exposure-outcome associations.To investigate whether CYP2E1 and GSTZ1 genetic polymorphisms modified the associations of prenatal DBP exposures with adverse birth outcomes.Two biomarkers of DBP exposures including trihalomethanes (THMs) in blood and trichloroacetic acid (TCAA) in urine were determined among 426 pregnant women from a Chinese cohort study. CYP2E1 (rs2031920, rs3813867, and rs915906) and GSTZ1 (rs7975) polymorphisms in cord blood were genotyped. Statistical interactions between prenatal DBP exposures and newborns CYP2E1 and GSTZ1 polymorphisms on birth outcomes (birth weight, birth length, and gestational age) were examined by multivariable linear regression with adjustment for potential confounders.We found that newborns CYP2E1 genetic polymorphisms (rs2031920 and rs3813867) modified the associations of maternal blood THMs or urinary TCAA levels with birth outcomes. However, these interactions were nonsignificant after Bonferroni correction for multiple comparisons, except for the interaction between maternal blood BrTHMs [sum of dibromochloromethane (DBCM), bromodichloromethane (BDCM), and bromoform (TBM)] and newborns CYP2E1 gene rs2031920 polymorphisms on birth weight (P for interaction = 0.003).Newborns genetic variations of CYP2E1 rs2031920 may modify the impacts of prenatal BrTHM exposure on birth weight. This finding needs to be further confirmed.

The intensive use of pesticide and plastic mulches has considerably enhanced crop growth and yield. Pesticide residues and plastic debris, however, have caused serious environmental problems. This study investigated the effects of the commonly used herbicide glyphosate and micrometre-sized plastic debris, referred as microplastics, on glyphosate decay and soil microbial activities in Chinese loess soil by a microcosm experiment over 30 days incubation. Results showed that glyphosate decay was gradual and followed a single first-order decay kinetics model. In different treatments (with/without microplastic addition), glyphosate showed similar half-lives (32.8 days). The soil content of aminomethylphosphonic acid (AMPA), the main metabolite of glyphosate, steadily increased without reaching plateau and declining phases throughout the experiment. Soil microbial respiration significantly changed throughout the entirety of the experiment, particularly in the treatments with higher microplastic addition. The dynamics of soil β-glucosidase, urease and phosphatase varied, especially in the treatments with high microplastic addition. Particles that were considerably smaller than the initially added microplastic particles were observed after 30 days incubation. This result thus implied that microplastic would hardly affect glyphosate decay but smaller plastic particles accumulated in soils which potentially threaten soil quality would be further concerned especially in the regions with intensive plastic mulching application.

Although the aggregation of graphene oxide (GO) has been widely researched, the influence of the GO size on the homoaggregation behavior and its interaction with environmental media are still unexplored. In this work, critical coagulation concentration (CCC) values for GO with different sizes, from micro to nanosheet, were measured with NaCl and CaCl₂ electrolytes, and the results indicated that GO with the largest size presented the smallest CCC value. Aluminum oxide (Al₂O₃) was selected as a natural solid particle representative to mimic the interaction between GO and environmental media. Batch experiments were conducted in solution with different pH and ionic strength. Results indicated that the attachment capacity of large GO onto Al₂O₃ particles was greater than that of small GO. The experimental data were well fitted with Freundlich model. The electrostatic attraction and hydrogen-bonding interaction dominated the interaction process between GO and Al₂O₃. These findings are important for better understanding in the environmental fate and transport of GO.

We assessed the potential role played by two vital Northeastern Pacific Ocean forage fishes, the Pacific sand lance (Ammodytes personatus) and Pacific herring (Clupea pallasii), as conduits for the vertical transfer of microfibres in food webs. We quantified the number of microfibres found in the stomachs of 734 sand lance and 205 herring that had been captured by an abundant seabird, the rhinoceros auklet (Cerorhinca monocerata). Sampling took place on six widely-dispersed breeding colonies in British Columbia, Canada, and Washington State, USA, over one to eight years. The North Pacific Ocean is a global hotspot for pollution, yet few sand lance (1.5%) or herring (2.0%) had ingested microfibres. In addition, there was no systematic relationship between the prevalence of microplastics in the fish stomachs vs. in waters around three of our study colonies (measured in an earlier study). Sampling at a single site (Protection Island, WA) in a single year (2016) yielded most (sand lance) or all (herring) of the microfibres recovered over the 30 colony-years of sampling involved in this study, yet no microfibres had been recovered there, in either species, in the previous year. We thus found no evidence that sand lance and herring currently act as major food-web conduits for microfibres along British Columbia's outer coast, nor that the local at-sea density of plastic necessarily determines how much plastic enters marine food webs via zooplanktivores. Extensive urban development around the Salish Sea probably explains the elevated microfibre loads in fishes collected on Protection Island, but we cannot account for the between-year variation. Nonetheless, the existence of such marked interannual variation indicates the importance of measuring year-to-year variation in microfibre pollution both at sea and in marine biota.