Chlorinated and brominated polycyclic aromatic hydrocarbons (Cl/Br-PAHs) are emerging semi-volatile organic pollutants in haze-associated particulate matter (PM). Their gas–particle phase partitioning and distribution among PM fractions have not been clarified. Clarification would increase understanding of atmospheric behavior and health risks of Cl/Br-PAHs. In this study, samples of the gas phase and 4 PM phases (aerodynamic diameters (dae) > 10 μm, 2.5–10 μm, 1.0–2.5 μm, and <1.0 μm) were collected simultaneously during haze events in Beijing and analyzed. Normalized histogram distribution indicated that the Cl/Br-PAHs tended to adhere to fine particles. Over 80% of the Cl-PAHs and 70% of the Br-PAHs were associated with fine PM (dae < 2.5 μm). The gas–particle phase partitioning and PM distribution of Cl/Br-PAHs when heating of buildings was required, which was associated with haze events, were obviously different from those when heating was not required. The relationship between the logarithmic geometric mean diameters of the Cl/Br-PAH congeners and reciprocal of the temperature (1/T) suggested that low air temperatures during the heating period could lead to high proportions of Cl/Br-PAHs in the fine particles. Increased coal burning during the heating period also contributed to high Cl/Br-PAH loads in the fine particles.

Road-deposited sediment and its adsorbed pollutants have been regarded as significant sources of urban diffuse pollution. In this study, the solid-phase concentrations (mg/g), surface load (mg/m2) and chemical fractionation of zinc (Zn), copper (Cu) and cadmium (Cd) were determined. Geo-accumulation (Igeo) and ecological risk (RI) indexes were employed for metal risk assessment. Results show that the highest solid-phase concentrations of Zn and Cu were usually found at an industrial area. However, Cd had the highest solid-phase concentrations at a rural area, followed by a commercial area. The surface loads of Zn and Cu decreased along the city centre to city border gradient. However, Cd was distributed irregularly. In terms of chemical fractionation, the predominant components of Zn and Cd were identified in the unstable exchangeable fractions, indicating high potential ecological risks to the aquatic environments. Cu posed a comparably low risk due to the high proportions of the stable components of residual and oxidizable fractions. According to a two-dimensional hierarchical cluster analysis, Zn and Cu surface loads were dominantly influenced by the antecedent dry-weather period; Cd contents were strongly land-use type dependent. In addition, the enrichment capability was ranked as Zn > Cu > Cd determined by Igeo index. The sampling site dependent potential ecological risk was determined as rural area (R) > commercial city centre (W) > federal highway (B) > industrial area (I) > main road (S) > secondary road (A) by the RI index.

Human exposure to polybrominated diphenyl ethers (PBDEs) has been increasing over the last three decades in China and around the world. Animal studies suggest that PBDEs could reduce blood levels of thyroid hormones, but it is unclear whether PBDEs disrupt thyroid function in humans. We used data from a prospective birth cohort of 123 pregnant women who were enrolled between September 2010 and March 2011 in Shandong, China. We measured the concentrations of eight PBDE congeners (n = 106) and five thyroid hormones (n = 107) in cord serum samples. We examined the relationship between prenatal exposure to PBDEs and thyroid function (n = 90). Median concentrations of BDEs 47, 99, 100, and 153 (detection frequencies > 75%) were 3.96, 8.27, 3.31, and 1.89 ng/g lipid, respectively. A 10-fold increase in BDE-99 and Σ4 PBDEs (the sum of BDEs 47, 99, 100, and 153) concentrations was associated with a 0.41 μg/dL (95% confidence interval [CI]: 0.10 to 0.72) and 0.37 μg/dL (95% CI: 0.06 to 0.68) increase in total thyroxine levels (TT4), respectively. No associations were found between other individual congeners and any of the five thyroid hormones. Our study suggests that prenatal exposure to PBDEs may be associated with higher TT4 in cord blood. Given the inconsistent findings across existing studies, our results need to be confirmed in additional studies.

Mercury (Hg) concentrations and nitrogen (δ15N) and carbon (δ13C) stable isotopic ratios were measured to assess differences in Hg bioaccumulation in four predatory fish species (Mycteroperca microlepis, Lutjanus campechanus, Caulolatilus microps, and Serioli dumerili) of high commercial and recreational importance in Atlantic waters of the southeastern US. Positive relationships existed between Hg and length, weight, and age, for all species, strongest for M. microlepis and L. campechanus. Intraspecific Hg concentrations also strongly correlated with δ15N for all species, and δ13C for only L. campechanus, and S. dumerili. Comparisons of stable isotopes between species and their impact on mean Hg concentration were inconclusive. This study is the first to report Hg concentrations for C. microps. The current study provides data for an under-sampled region, explores how feeding ecology impacts Hg uptake in commonly co-occurring fishes, and raises questions of the importance of sex and reproduction in Hg accumulation for marine fishes.

Pyrethroid insecticides are widely used in urban environments, and their occurrence has been recently associated with aquatic toxicity in urban surface streams. Synthetic pyrethroids are strongly hydrophobic compounds, highlighting the importance of the freely dissolved concentration (Cfree), rather than the total chemical concentration, for better prediction of potential effects in aquatic ecosystems. The goal of this study was to develop a simple, robust and field-applicable passive sampling methodology that may be used for in situ monitoring of trace levels of pyrethroids in surface water. Among a range of polymer films, polyethylene film (PE) was found to be the most efficient at absorbing pyrethroids from water. To circumvent the long equilibrium time, 13C-permethrin and bifenthrin-d5 were preloaded on the PE sampler as performance reference compounds (PRC). Desorption of isotope-labeled PRCs was found to be isotropic to the absorption of target analytes. The optimized method was first tested in large circulating tanks simulating various environmental conditions. The derived Cfree values were consistently smaller than the total aqueous concentration in salt water or water containing humic acids. The PE samplers were further deployed at multiple field sites for 7 d in Southern California and analysis demonstrated good monitoring reproducibility and sensitivity under ambient environmental conditions. The developed passive sampler approach is ideal for application for in situ sampling under field conditions, and the use of PRCs allows sampling with short and flexible time intervals.

Antibiotics and antibiotic resistance genes (ARGs) in soil can affect human health via the food chain. Biochar is a soil amendment but its impacts on ARGs and the microbial communities associated with soil and vegetables are unclear. Therefore, we established three lettuce pot culture experiments, i.e., O300: 300 mg/kg oxytetracycline (OTC), BO300: 300 mg/kg OTC + 2% biochar, and a control without OTC or biochar. We found that under BO300, the relative abundances of ARGs were reduced by 51.8%, 43.4%, and 44.1% in lettuce leaves, roots, and soil, respectively, compared with O300. intI1 was highly abundant in soil and lettuce, and it co-occurred with some ARGs (tetW, ermF, and sul1). Redundancy analysis and network analysis indicated that the bacterial community succession was the main mechanism that affected the variations in ARGs and intI1. The reduction of Firmicutes due to the biochar treatment of soil and lettuce was the main factor responsible for the removal of tetracycline resistance genes in leaves. Biochar application led to the disappearance of human pathogenic bacteria (HPB), which was significantly correlated with the abundances of ermF and ermX. In summary, biochar is an effective farmland amendment for reducing the abundances of antibiotics, ARGs, and HPB in order to ensure the safety of vegetables and protect human health.

Like many urban catchments, the River Thames in London is contaminated with plastics. This pollutant is recorded on the river banks, in the benthic environment and in the water column. The present study was conducted to assess the extent of microplastic ingestion in two River Thames fish species, the European flounder (Platichthys flesus) and European smelt (Osmerus eperlanus). Samples were collected from two sites in Kent, England; Erith and Isle of Grain/Sheppey, near Sheerness, with the latter being more estuarine. The results revealed that up to 75% of sampled European flounder had plastic fibres in the gut compared with only 20% of smelt. This difference may be related to their diverse feeding behaviours: European flounder are benthic feeders whilst European smelt are pelagic predators. The fibres were predominantly red or black polyamides and other fibres included acrylic, nylon, polyethylene and polyethylene terephthalate and there was no difference in occurrence between the sites sampled.

Bacteriophages (phages) are the most abundant and diverse biological entities in our planet. They infect susceptible bacterial hosts into which they either multiply or persist. In the latter case, phages can confer new functions to their hosts as a result of gene transfer, thus contributing to their adaptation (short-term) and evolution (long-term). In this regard, the role of phages on the dissemination of antibiotic resistance genes (ARGs) among bacterial hosts in natural environments has not yet been clearly resolved. Here, we carry out a comprehensive analysis of thirty-three viromes from different habitats to investigate whether phages harbor ARGs. Our results demonstrate that while human-associated viromes do not or rarely carry ARGs, viromes from non-human sources (e.g. pig feces, raw sewage, and freshwater and marine environments) contain a large reservoir of ARGs, thus pointing out that phages could play a part on the spread of antibiotic resistance. Given this, the role of phages should not be underestimated and it should be considered when designing strategies to tackle the global crisis of antibiotic resistance.

Urban greenspaces provide ecosystem services like more natural ecosystems do. For instance, vegetation modifies soil properties, including pH and soil organic matter content, yet little is known about its effect on metals. We investigated whether the accumulation and mobility of heavy metals, nutrients and carbon is affected by plant functional types (evergreen or deciduous trees, lawns) in urban parks of varying ages in southern Finland. Plant types modified soil physico-chemical parameters differently, resulting in diverging accumulation and mobility of metals and other elements in park soils. However, the effects of plant functional type depended on park age: lawns in parks of ca. 50 y old had the highest contents of Cr, Cu, Fe, Mn, Ni, and Zn, and in these, and older parks (>100 y old), contents of most metals were lowest under evergreen trees. The mobility of metals and other elements was influenced by the amount of water leached through the soils, highlighting the importance of vegetation on hydrology. Soils under evergreen trees in young parks and lawns in intermediately-aged parks were most permeable to water, and thus had high loads of Ca, Cr, Cu, Fe, Ni, tot-P and tot-N. The loads/concentrations of elements in the leachates was not clearly reflected by their content/concentration in the soil, alluding to the storage capacity of these elements in urban park soils. Our results suggest that in urban systems with a high proportion of impermeable surfaces, park soil has the potential to store nutrients and metals and provide an important ecosystem service particularly in polluted cities.

Municipal wastewater contains multi-component mixtures of active pharmaceutical ingredients (APIs). This could shape microbial communities in sewage treatment plants (STPs) and the effluent-receiving ecosystems. In this paper we assess the risk of antimicrobial effects in STPs and the aquatic environment for a mixture of 18 APIs that was previously detected in the effluent of a European municipal STP. Effects on microbial consortia (collected from a separate STP) were determined using respirometry, enumeration of culturable microorganisms and community-level physiological profiling. The mixture toxicity against selected bacteria was assessed using assays with Pseudomonas putida and Vibrio fischeri. Additional data on the toxicity to environmental bacteria were compiled from literature in order to assess the individual and expected joint bacterial toxicity of the pharmaceuticals in the mixture. The reported effluent concentration of the mixture was 15.4 nmol/l and the lowest experimentally obtained effect concentrations (EC10) were 242 nmol/l for microbial consortia in STPs, 225 nmol/l for P. putida and 73 nmol/l for V. fischeri. The lowest published effect concentrations (EC50) of the individual antibiotics in the mixture range between 15 and 150 nmol/l, whereas 0.9–190 μmol/l was the range of bacterial EC50 values found for the non-antibiotic mixture components. Pharmaceutical cocktails could shape microbial communities at concentrations relevant to STPs and the effluent receiving aquatic environment. The risk of antimicrobial mixture effects was completely dominated by the presence of antibiotics, whereas other pharmaceutical classes contributed only negligibly to the mixture toxicity. The joint bacterial toxicity can be accurately predicted from the individual toxicity of the mixture components, provided that standardized data on representative bacterial strains becomes available for all relevant compounds. These findings argue for a more sophisticated bacterial toxicity assessment of environmentally relevant pharmaceuticals, especially for those with a mode of action that is known to specifically affect prokaryotic microorganisms.