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.

The placenta is an intermediary organ between the female and the developing foetus. Some chemical substances, including the most harmful ones, exhibit the ability to accumulate in or penetrate through the placenta. The aim of the study was to determine the role of the placenta of the Baltic grey seal (Halichoerus grypus grypus) in the transfer of endocrine disrupting compounds (EDCs) - (bisphenol A, 4-tert- octylphenol, 4- nonylphenol), as well as total and organic mercury. 30 placentas were collected from grey seals pupping under human care at the Hel Marine Station in the years 2007–2016. The assays were conducted using the technique of high-preformance liquid chromatography (phenol derivatives) and atomic absorption spectrometry (mercury and selenium). A measurable level of EDCs was indicated in the placentas of grey seals. It was established that the inorganic Hg form was accumulated in the placenta, and that its concentrations were an order of magnitude higher than the concentrations of the organic form, which penetrated to the foetus. Similar observations were made for phenol derivatives - bisphenol A, 4-tert- octylphenol and 4-nonylphenol. For this compound group the placenta was a barrier, but the properties of phenol derivatives suggest the possibility of their penetration through this organ.

Genome fragment enrichment (GFE) method was applied to identify host-specific bacterial genetic markers that differ among different fecal metagenomes. To enrich for swine-specific DNA fragments, swine fecal DNA composite (n = 34) was challenged against a DNA composite consisting of cow, human, goat, sheep, chicken, duck and goose fecal DNA extracts (n = 83). Bioinformatic analyses of 384 non-redundant swine enriched metagenomic sequences indicated a preponderance of Bacteroidales-like regions predicted to encode metabolism-associated, cellular processes and information storage and processing. After challenged against fecal DNA extracted from different animal sources, four sequences from the clone libraries targeting two Bacteroidales- (genes 1–38 and 3–53), a Clostridia- (gene 2–109) as well as a Bacilli-like sequence (gene 2–95), respectively, showed high specificity to swine feces based on PCR analysis. Host-specificity and host-sensitivity analysis confirmed that oligonucleotide primers and probes capable of annealing to select Bacteroidales-like sequences (1–38 and 3–53) exhibited high specificity (>90%) in quantitative PCR assays with 71 fecal DNAs from non-target animal sources. The two assays also demonstrated broad distributions of corresponding genetic markers (>94% positive) among 72 swine feces. After evaluation with environmental water samples from different areas, swine-targeted assays based on two Bacteroidales-like GFE sequences appear to be suitable quantitative tracing tools for swine fecal pollution.

Studies have shown that pig manure is a reservoir of antibiotic resistance genes (ARGs). However, little is known about the characteristics of ARGs in the manure of piglets and adult pigs fed on different diets. In the present study, the ARG characteristics of the manure of piglets and adult pigs fed on different diets (feed, grain) were analyzed using high-throughput fluorescence quantitative PCR. Correlations between heavy metals, antibiotics, and ARGs in pig manure were analyzed. The results showed that the heavy metal and antibiotic contents in the manure of pigs receiving feed significantly exceeded those in the manure of pigs receiving grain. The heavy metal and antibiotic contents were higher in manure of piglets than in that of adult pigs. Feed significantly increased the ARG diversity in the pig manure. The ARG diversity was higher in manure of piglets than in that of adult pigs. In the manure of pigs receiving feed, 25 (from piglets), 12 (from adult pigs) ARGs were enriched significantly compared with pig fed with grain. In particular, sat4 (in piglets) and vatE-01 (in adult pigs) showed the highest enrichment, being increased by 59 and 19-fold, respectively. The ARG diversity correlated positively with the concentrations of antibiotics and heavy metals in the manure.

Over 700 million people in Sub-Saharan Africa depend on solid biomass fuel and use simple cookstoves in poorly ventilated kitchens, which results in high indoor concentrations of household air pollutants. Switching from biomass to biogas as a cooking fuel can reduce airborne emissions of fine particulate matter (PM2.5) and carbon monoxide (CO), but households often only partially convert to biogas, continuing to use solid biomass fuels for part of their daily cooking needs. There is little evidence of the benefits of partial switching to biogas. This study monitored real-time PM2.5 and CO concentrations in 35 households in Cameroon and Uganda where biogas and firewood (or charcoal) were used. The 24 h mean PM2.5 concentrations in households that used: (1) firewood and charcoal; (2) both firewood (mean 54% cooking time) and biogas (mean 46% cooking time); and (3) only biogas, were 449 μg m⁻³, 173 μg m⁻³ and 18 μg m⁻³ respectively. The corresponding 24 h mean CO concentrations were 14.2 ppm, 2.7 ppm and 0.5 ppm. Concentrations of both PM2.5 and CO were high and exceeded the World Health Organisation guidelines when firewood and charcoal were used. Partially switching to biogas reduced CO exposure to below the World Health Organisation guidelines, but PM2.5 concentrations were only below the 24 h recommended limits when households fully converted to biogas fuel. These results indicate that partial switching from solid fuels to biogas is not sufficient and continues to produce concentrations of household air pollution that are likely to harm the health of those exposed. Programmes introducing biogas should aim to ensure that household energy needs can be fully achieved using biogas with no requirement to continue using solid fuels.

We aimed to clarify the effects of ozone (O3) on photosynthetic ability of upper and lower canopy leaves of Fagus crenata Blume seedlings grown under different soil nutrient conditions. To accomplish this objective, we analyzed the response of photosynthetic parameters such as maximum carboxylation rate (Vcmax) to cumulative stomatal O3 uptake (ΣFst) and reduction rate of Vcmax per unit ΣFst as an index of detoxification capacity for O3. The seedlings of Fagus crenata were grown for two growing seasons (2014–2015) in nine treatments comprised of a combination of three levels of gas treatments (charcoal-filtered air or 1.0- or 1.5-times ambient O3 concentration) and three levels of soil nutrient treatments (non-fertilized or a supply of relatively low or high concentrations of compound fertilizer). The nutrient supply significantly increased the degree of O3-induced reduction in Vcmax in September. However, nutrient supply did not significantly increase ΣFst and reduce the detoxification capacity for O3. On the other hand, the degree of O3-induced reduction in Vcmax of upper canopy leaves was higher as compared with that of lower canopy leaves in August due to the higher ΣFst. However, the reduction rate of Vcmax per unit ΣFst in lower canopy leaves was higher than that in upper canopy leaves, indicating lower detoxification capacity for O3 in lower canopy leaves. Reduction rate of Vcmax per unit ΣFst over the threshold, which is assumed to be proportional to gross photosynthetic rate, was similar between upper and lower canopy leaves. Therefore, capacity of photosynthetic CO2 assimilation is likely to be associated with detoxification capacity for O3 in upper and lower canopy leaves of F. crenata seedlings grown under different soil nutrient conditions.

High nitrogen (N) inputs in Chinese vegetable and cereal productions played key roles in increasing crop yields. However, emissions of the potent greenhouse gas nitrous oxide (N2O) and atmospheric pollutant nitric oxide (NO) increased too. For lowering the environmental costs of crop production, it is essential to optimize N strategies to maintain high crop productivity, while reducing the associated N losses. We performed a 2 year-round field study regarding the effect of different combinations of poultry manure and chemical N fertilizers on crop yields, N use efficiency (NUE) and N2O and NO fluxes from a Welsh onion-winter wheat system in the North China Plain. Annual N2O and NO emissions averaged 1.14–3.82 kg N ha⁻¹ yr⁻¹ (or 5.54–13.06 g N kg⁻¹ N uptake) and 0.57–1.87 kg N ha⁻¹ yr⁻¹ (or 2.78–6.38 g N kg⁻¹ N uptake) over all treatments, respectively. Both N2O and NO emissions increased linearly with increasing total N inputs, and the mean annual direct emission factors (EFd) were 0.39% for N2O and 0.19% for NO. Interestingly, the EFd for chemical N fertilizers (N2O: 0.42–0.48%; NO: 0.07–0.11%) was significantly lower than for manure N (N2O: 1.35%; NO: 0.76%). Besides, a negative power relationship between yield-scaled N2O, NO or N2O + NO emissions and NUE was observed, suggesting that improving NUE in crop production is crucial for increasing crop yields while decreasing nitrogenous gas release. Compared to the current farmers’ fertilization rate, alternative practices with reduced chemical N fertilizers increased NUE and decreased annual N2O + NO emissions substantially, while crop yields remained unaffected. As a result, annual yield-scaled N2O + NO emissions were reduced by > 20%. Our study shows that a reduction of current application rates of chemical N fertilizers by 30–50% does not affect crop productivity, while at the same time N2O and NO emissions would be reduced significantly.

Pharmaceutical and personal care products (PPCPs) are continuously introduced into the soil-plant system, through practices such as agronomic use of reclaimed water and biosolids containing these trace contaminants. Plants may accumulate PPCPs from soil, serving as a conduit for human exposure. Metabolism likely controls the final accumulation of PPCPs in plants, but is in general poorly understood for emerging contaminants. In this study, we used diclofenac as a model compound, and employed 14C tracing, and time-of-flight (TOF) and triple quadruple (QqQ) mass spectrometers to unravel its metabolism pathways in Arabidopsis thaliana cells. We further validated the primary metabolites in Arabidopsis seedlings. Diclofenac was quickly taken up into A. thaliana cells. Phase I metabolism involved hydroxylation and successive oxidation and cyclization reactions. However, Phase I metabolites did not accumulate appreciably; they were instead rapidly conjugated with sulfate, glucose, and glutamic acid through Phase II metabolism. In particular, diclofenac parent was directly conjugated with glutamic acid, with acyl-glutamatyl-diclofenac accounting for >70% of the extractable metabolites after 120-h incubation. In addition, at the end of incubation, >40% of the spiked diclofenac was in the non-extractable form, suggesting extensive sequestration into cell matter. The rapid formation of non-extractable residue and dominance of diclofenac-glutamate conjugate uncover previously unknown metabolism pathways for diclofenac. In particular, the rapid conjugation of parent highlights the need to consider conjugates of emerging contaminants in higher plants, and their biological activity and human health implications.

Scientifically sound risk assessment strategies and derivations of environmental quality standards for metals present in freshwater environments are currently hampered by insufficient chronic toxicity data collected from natural ecosystems, as well as inadequate information on metal speciation. Thus, the aim of the present study was to evaluate the impact of freshwater containing multiple metals (Cd, Cr, Cu, Ni, Pb and Zn) on the chronic toxicity (72h) to the alga Pseudokirchneriella subcapitata and compare the observed toxicity results to the total and free metal concentration of the samples. Based on the information obtained herein, an additive inhibitory free multi-metal ion concentration index, calculated as the sum of the equivalent toxicities to the free metal ion concentration of each sample, was developed. The proposed index was well correlated to the observed chronic toxicity results, indicating that the concentration addition, when expressed as the free-ion activity, can be considered a reliable indicator for the evaluation of ecological risk assessments for natural waters containing multiple metals.

Glaciers, particularly alpine glaciers, have been receding globally at an accelerated rate in recent decades. The glacial melt-induced release of pollutants (e.g., mercury) and its potential impact on the atmosphere and glacier-fed ecosystems has drawn increasing concerns. During 15th–20th August, 2011, an intensive sampling campaign was conducted in Qugaqie Basin (QB), a typical high mountain glacierized catchment in the inland Tibetan Plateau, to investigate the export and transport of mercury from glacier to runoff. The total mercury (THg) level in Zhadang (ZD) glacier ranged from <1 to 20.8 ng L−1, and was slightly higher than levels measured in glacier melt water and the glacier-fed river. Particulate Hg (PHg) was the predominant form of Hg in all sampled environmental matrices. Mercury concentration in Qugaqie River (QR) was characterized by a clear diurnal variation which is linked to glacier melt. The estimated annual Hg exports by ZD glacier, the upper river basin and the entire QB were 8.76, 7.3 and 157.85 g, respectively, with respective yields of 4.61, 0.99 and 2.74 μg m−2 yr−1. Unique landforms and significant gradients from the glacier terminus to QB estuary might promote weathering and erosion, thereby controlling the transport of total suspended particulates (TSP) and PHg. In comparison with other glacier-fed rivers, QB has a small Hg export yet remarkably high Hg yield, underlining the significant impact of melting alpine glaciers on regional Hg biogeochemical cycles. Such impacts are expected to be enhanced in high altitude regions under the changing climate.