Besides stomatal closure, biological detoxification is an important protection mechanism for plants against ozone (O3). This study investigated the diurnal changes of ascorbate (a major detoxification agent) in the apoplast and leaf tissues of winter wheat grown under ambient air field conditions. Results showed the reduced ascorbate in the apoplast (ASCapo) exhibited a peak in late morning or midday, mismatching with either the maximum external O3 concentrations in mid-afternoon or the maximum stomatal O3 uptake between late morning and mid-afternoon. In contrast, the ASC in leaf tissues remained stable throughout the day. The investigations conducted in a Free-Air Concentration Elevation of O3 system confirmed that the diurnal variations of the ASCapo were induced more by the daily variations of O3 concentrations rather than the cumulative O3 effects. In conclusion, the O3-stress detoxification should be a dynamic variable rather than a fixed threshold as assumed in the stomatal flux-based O3 dose metrics.

Rice and the distinctive cultivation practices employed in rice growth can significantly influence the environmental fate of polybrominated diphenyl ethers (PBDEs) in a paddy field. We studied variations in PBDE concentrations in multiple compartments of a paddy field in the suburban area of Guangzhou, South China, including air, soil, water, and rice tissues. The input/output fluxes of air–surface and air–foliage exchange, atmospheric deposition and water input during different rice growth stages were measured simultaneously. Air–foliage and air–water diffusion exchanges were the key processes controlling inputs and outputs of PBDEs in paddy fields, respectively, whereas atmospheric deposition dominated inputs of higher brominated PBDEs. The high input of PBDEs via air–foliage exchange suggested that vegetation can significantly increase the air-to-field transport of PBDEs in ecosystems. The annual input of PBDEs in all paddy fields in Guangdong Province was estimated to be 22.1 kg.

Increasing commercial use of nanosilver has focussed attention on the fate of silver (Ag) in the wastewater release pathway. This paper reports the speciation and lability of Ag in archived, stockpiled, and contemporary biosolids from the UK, USA and Australia, and indicates that biosolids Ag concentrations have decreased significantly over recent decades. XANES revealed the importance of reduced-sulfur binding environments for Ag speciation in materials ranging from freshly produced sludge to biosolids weathered under ambient environmental conditions for more than 50 years. Isotopic dilution with 110mAg showed that Ag was predominantly non-labile in both fresh and aged biosolids (13.7% mean lability), with E-values ranging from 0.3 to 60 mg/kg and 5 mM CaNO3 extractable Ag from 1.2 to 609 μg/kg (0.002–3.4% of the total Ag). This study indicates that at the time of soil application, biosolids Ag will be predominantly Ag-sulfides and characterised by low isotopic lability.

Health effects by consuming urban garden products are discussed controversially due to high urban pollution loads. We sampled wild edible mushrooms of different habitats and commercial mushroom cultivars exposed to high traffic areas within Berlin, Germany. We determined the content of cadmium and lead in the fruiting bodies and analysed how the local setting shaped the concentration patterns. EU standards for cultivated mushrooms were exceeded by 86% of the wild mushroom samples for lead and by 54% for cadmium but not by mushroom cultures. We revealed significant differences in trace metal content depending on species, trophic status, habitat and local traffic burden. Higher overall traffic burden increased trace metal content in the biomass of wild mushrooms, whereas cultivated mushrooms exposed to inner city high traffic areas had significantly lower trace metal contents. Based on these we discuss the consequences for the consumption of mushrooms originating from urban areas.

In this paper, we review recent publications regarding the toxicokinetics and -dynamics of the flame retardant Hexabromocyclododecane (HBCD). HBCD has recently been listed as a persistent organic pollutant, which therefore influenced the legislation concerning its manufacturing and formulation. However, under specific circumstances it may still be used until 2024. Early toxicity studies have only focussed on HBCD itself, which is a mixture of different isomers with different physical and toxicological characteristics. Here we take a more differentiated look at the three diastereomers α-, β- and γ-HBCD. We also address the different enantiomers to give an overview of the toxicity of HBCD to identify present gaps in our knowledge about this chemical, especially with respect to its possible formulation until 2024.

Lichens, symbioses of fungi and algae and/or cyanobacteria, have the remarkable ability to uptake and accumulate semivolatile organic compounds (SVOC) from air, including polycyclic aromatic hydrocarbons (PAHs), but the mechanism of accumulation is still unknown. Understanding these mechanisms is critical to standardize the use of lichens as environmental bioindicators and to further integrate them in air monitoring networks. Through a series of experiments we show that gas phase PAHs easily cross lichen's surface and accumulate in the photosynthetic algal layer of lichens. Once accumulated, they remain in the algal layer and not within the fungus hyphae, or adhered to lichen's surface, as it was previously supposed to happen. Additionally, when lichens are washed, gas phase PAHs still remain in the algal layer. Our results reveal that lichens may be utilized as bioindicators of gas phase PAHs, overcoming current limitations of air monitoring.

The sorption of two phthalate esters (PAEs) and phenanthrene (PHE) by different natural organic matter fractions (NOMs) was examined. The surface area of the NOMs correlated positively with the starting decomposition temperature (SDT), implying increased number of micropores with the rise of condensation. Sorption of PHE on nonhydrolyzable carbons (NHCs) and other NOMs was respectively dependent on aromatic and aliphatic C contents. Likely physical blocking of the aliphatic moieties and input of black carbon materials led to elevated sorption capacity for PHE of aromatic domains in the NHCs. Sorption of PAEs by NOMs excluding NHCs was jointly regulated by hydrophobic partitioning and H-bonding interactions. The SDT of the NOMs correlated negatively with the Koc when SDT ≥304 °C, likely because the highly condensed domains may impair the availability of amorphous moieties for sorption. This study highlights the influence of domain accessibility of NOMs on sorption of hydrophobic organic contaminants.

A series of experiments were performed to simulate the environmental behavior and fate of graphene oxide nanoparticles (GONPs) involved in the surface environment relating to divalent cations, natural organic matter (NOM), and hydraulics. The electrokinetic properties and hydrodynamic diameters of GONPs was systematically determined to characterize GONPs stability and the results indicated Ca2+ (Mg2+) significantly destabilized GONPs with high aggregate strength factors (SF) and fractal dimension (FD), whereas NOM decreased aggregate SF with lower FD and improved GONPs stability primarily because of increasing steric repulsion and electrostatic repulsion. Furthermore, the GONPs resuspension from the sand bed into overlying water with shear flow confirmed that the release would be restricted by Ca2+ (Mg2+), however, enhanced by NOM. The interaction energy based on Derjaguin–Landau–Verwey–Overbeek theory verifies the aggregation and resuspension well. Overall, these experiments provide an innovative look and more details to study the behavior and fate of GONPs.

We collected O- and A-horizon soil samples in 26 Chinese mountainous forests to investigate the content, spatial pattern, and potential sources of polychlorinated naphthalenes (PCNs). Spatial patterns were influenced mainly by the approximation to sources and soil organic contents. High concentrations often occurred close to populated or industrialized areas. Combustion-related activities contributed to PCN pollution. Relatively high proportions of CN-73 in northern China may be attributed to coke consumption, while CN-51 could be an indicator of biomass burning in Southwest China. There are evidences that PCNs may largely derived from unintentional production. If uncontrolled, UP-PCN (unintentionally produced PCNs) emissions could increase with industrial development. The abnormally high concentrations at Gongga and Changbai Mountains appear to be associated with the high efficient of forest filter of atmospheric contaminants at these densely forested sites. We question whether this is caused by ecotones between forests, and raise additional questions for future analyses.

Halogenated nitrogenous disinfection byproducts (N-DBPs) raise concerns regarding their mutagenicity and carcinogenicity threatening public health. However, environmental consequence of their mutagenicity has received less attention. In this study, the effect of halogenated N-DBPs on bacterial antibiotic resistance (BAR) was investigated. After exposure to bromoacetamide (BAcAm), trichloroacetonitrile (TCAN) or tribromonitromethane (TBNM), the resistance of Pseudomonas aeruginosa PAO1 to both individual and multiple antibiotics (ciprofloxacin, gentamicin, polymyxin B, rifampin, tetracycline, ciprofloxacin + gentamicin and ciprofloxacin + tetracycline) was increased, which was predominantly ascribed to the overexpression of efflux pumps. The mechanism of this effect was demonstrated to be mutagenesis through sequencing and analyzing antibiotic resistance genes. The same induction phenomena also appeared in Escherichia coli, suggesting this effect may be universal to waterborne pathogens. Therefore, more attention should be given to halogenated N-DBPs, as they could increase not only genotoxicological risks but also epidemiological risks of drinking water.