In recent years, air pollution events have occurred frequently in China during the winter. Most studies have focused on the physical and chemical composition of polluted air. Some studies have examined the bacterial bioaerosols both indoors and outdoors. But few studies have focused on the relationship between air pollution and bacteria, especially pathogenic bacteria. Airborne PM samples with different diameters and different air quality index values were collected in Hangzhou, China from December 2014 to January 2015. High-throughput sequencing of 16S rRNA was used to categorize the airborne bacteria. Based on the NCBI database, the “Human Pathogen Database” was established, which is related to human health. Among all the PM samples, the diversity and concentration of total bacteria were lowest in the moderately or heavily polluted air. However, in the PM2.5 and PM10 samples, the relative abundances of pathogenic bacteria were highest in the heavily and moderately polluted air respectively. Considering the PM samples with different particle sizes, the diversities of total bacteria and the proportion of pathogenic bacteria in the PM10 samples were different from those in the PM2.5 and TSP samples. The composition of PM samples with different sizes range may be responsible for the variances. The relative humidity, carbon monoxide and ozone concentrations were the main factors, which affected the diversity of total bacteria and the proportion of pathogenic bacteria. Among the different environmental samples, the compositions of the total bacteria were very similar in all the airborne PM samples, but different from those in the water, surface soil, and ground dust samples. Which may be attributed to that the long-distance transport of the airflow may influence the composition of the airborne bacteria. This study of the pathogenic bacteria in airborne PM samples can provide a reference for environmental and public health researchers.

Laccases are capable of rapidly oxidizing benzo[a]pyrene. It is thought that the metabolites with an increase in water solubility caused by the oxidation of benzo[a]pyrene may stimulate the subsequent mineralization. However, to date, there has been no experimental evidence to support this. In this study, the fate of benzo[a]pyrene in soil affected by laccase amendment and the resulting soil bacterial responses were investigated. Laccase amendment promoted benzo[a]pyrene dissipation (15.6%) from soil, accompanied by trace mineralization (<0.58 ± 0.02%) and substantial bound residue formation (∼80%). An increase of ∼15% in the bound residue fraction was observed by laccase amendment, which mainly resulted from covalent binding of the residues to humin fraction. During the incubation, the abundance of bacterial 16S rRNA and polycyclic aromatic hydrocarbon ring-hydroxylating dioxygenase genes did not change markedly. In contrast, benzo[a]pyrene treated with laccase resulted in a smaller shift in the bacterial community composition, indicating a reduced disturbance to the soil microbial communities. These results here suggest that benzo[a]pyrene contaminated soil can be detoxified by laccase amendment mainly due to the enhanced bound residue formation to soil organic matter via covalent binding.

International audience | Biocontrol strategies are viewed as an environment friendly alternative to the use of conventional synthetic pesticides to control pests or weeds in agrosystems and are expected to supersede the use of pesticides. Nevertheless, biocontrol solutions are not devoid of drawbacks. As encountered with conventional pesticides, one can expect side-effects of biopesticides on non-targeted organisms and/or ecosystem processes. The "bio-" prefix in the word "biopesticides" does it necessarily guarantee their environment safe profile? In this context, we call to mind the researchers of the network ECOTOX (French network of ecotoxicology; https://www6.inra.fr/ecotox) in the framework of a roundtable entitled "Biocontrol & Ecotoxicology" on the following questions: who is experienced in ecotoxicology in relation with biocontrol in its own research? To what extend would it be useful to introduce ecotoxicology in biocontrol? What is the fate of biopesticides in the environment? What role could we cast to ecotoxicology in biocontrol regulations? We report here a synthesis of the discussions engaged during the roundtable.

Hourly concentrations of water-soluble inorganic ions (Na⁺, NH₄⁺, K⁺, Mg²⁺, Ca²⁺, Cl⁻, NO₃⁻ and SO₄²⁻) in PM₂.₅ and related reactive gases were measured with a Gas and Aerosol Collector combined with Ion Chromatography (GAC-IC) in urban Chengdu from April 17 to May 27, 2017, during which both haze and dust episodes occurred frequently. Nitrate was the most abundant ion in PM₂.₅ and substantially increased during haze pollution with the NO₃⁻/SO₄²⁻ mass ratio increasing from 0.78 during clean period to 1.1 during haze period. Aerosols in Chengdu were generally ammonium-rich, wherein ammonium nitrate was primarily formed through homogeneous gas-phase reactions and limited by the availability of HNO₃, indicating that preferentially reducing the emissions of NOx could make for mitigating spring haze pollution in Chengdu. Backward trajectory clustering coupled with measured species and a potential source contribution function (PSCF) for PM₂.₅, PM₁₀/PM₂.₅, sulfate, nitrate, ammonium, and Ca²⁺ indicated that regionally transported pollutants from the southern and southeastern Sichuan Basin strongly contributed to springtime PM₂.₅ pollution in Chengdu, but long-distance transport from northwestern China also contributed to dust pollution. Moreover, the treatment of urban fugitive dust in southern Sichuan is also important for reducing coarse particles in Chengdu. Therefore, the improvement of air quality in Chengdu, even in the Sichuan Basin, requires the regional joint emission reduction of particles and gaseous precursors across the entire Sichuan Basin, especially for cities located in southeastern Sichuan Basin.

Bisphenols, as synthetic chemicals, have been widely detected in environmental and human samples. Epidemiological studies have reported relationships between bisphenol A (BPA) and type 2 diabetes mellitus (T2DM), but results are inconsistent. Additionally, the associations between other bisphenols (i.e., the substitutes of BPA) with T2DM have been scarcely reported. A case-control study was conducted to examine the associations of urinary bisphenols with T2DM by investigating 8 bisphenols in urine samples of 251 T2DM cases and 251 controls and using different statistic models. Urinary bisphenol AF (BPAF) and bisphenol S (BPS) concentrations were significantly positively associated with T2DM in the log-transformed statistical models and adjusted odd ratios (ORs) were separately 4.95 [95% confidence interval (CI): 3.15, 7.79] and 1.73 (95% CI: 1.37, 2.18), which was consistent with the results in categorical models (OR = 2.03; 95% CI: 1.31, 3.15; p = 0.001 for BPAF; OR = 3.83; 95% CI: 2.37, 6.20; p < 0.001 for BPS). In addition, in the categorical models, elevated odds of T2DM were observed in the second BPA quartile (OR = 2.58; 95% CI: 1.38, 4.80) and the third quartile (OR = 1.89; 95% CI: 1.03, 3.46), but not in the fourth quartile, which reflected a nonlinear association between urinary BPA and T2DM. Similarly, only significant positive association with T2DM was found in the second quartile of the sum of bisphenols (OR = 2.07; 95% CI: 1.12, 3.82). In the sensitivity analyses, the associations of bisphenols with T2DM remained consistent except for BPAF in the categorical model. Our study suggested that several urinary bisphenols were positively associated with T2DM.

The concentrations of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) were measured for riverine and marine sediments from the Laizhou Bay area in order to investigate their spatial distributions, possible sources and transport behaviors. Concentrations of SCCPs and MCCPs in riverine sediments varied from 8.4 to 2000 ng g⁻¹ dw and from 1.8 to 3200 ng g⁻¹ dw, respectively. Higher concentrations were found exclusively at industrial sites. Emissions from local factories were the main source of CPs in river sediments of this region. It was 5–22 ng g-1 dw and 6–63 ng g⁻¹ dw with an average value of 11 ng g⁻¹ dw and 9 ng g⁻¹ dw for SCCPs and MCCPs in marine sediments of Laizhou Bay, respectively. In addition to riverine input, ship related emissions are suggested to be another important source of CPs in the Laizhou Bay. MCCPs/SCCPs values and compositional profiles of SCCPs were found to vary along with CP concentrations. A distinct shift to congener groups with shorter carbon chains and lower chlorination from emission sources to remote areas was noticed. The role of log octanol-water partition coefficient (LogKₒw) values indicated decisive in their transportation from emission sources to remote areas in the Laizhou Bay area.

Studies of source apportionment (SA) for particulate matter (PM) air pollution have enhanced understanding of dominant pollution sources and quantification of their contribution. Although there have been many SA studies in South Korea over the last two decades, few studies provided an integrated understanding of PM sources nationwide. The aim of this study was to summarize findings of PM SA studies of South Korea and to explore study characteristics.We selected studies that estimated sources of PM10 and PM2.5 performed for 2000–2017 in South Korea using Positive Matrix Factorization and Chemical Mass Balance. We reclassified the original PM sources identified in each study into seven categories: motor vehicle, secondary aerosol, soil dust, biomass/field burning, combustion/industry, natural source, and others. These seven source categories were summarized by using frequency and contribution across four regions, defined by northwest, west, southeast, and southwest regions, by PM10 and PM2.5. We also computed the population-weighted mean contribution of each source category. In addition, we compared study features including sampling design, sampling and lab analysis methods, chemical components, and the inclusion of Asian dust days.In the 21 selected studies, all six PM10 studies identified motor vehicle, soil dust, and combustion/industry, while all 15 PM2.5 studies identified motor vehicle and soil dust. Different from the frequency, secondary aerosol produced a large contribution to both PM10 and PM2.5. Motor vehicle contributed highly to both, whereas the contribution of combustion/industry was high for PM10. The population-weighted mean contribution was the highest for the motor vehicle and secondary aerosol sources for both PM10 and PM2.5. However, these results were based on different subsets of chemical speciation data collected at a single sampling site, commonly in metropolitan areas, with short overlap and measured by different lab analysis methods.We found that motor vehicle and secondary aerosol were the most common and influential sources for PM in South Korea. Our study, however, suggested a caution to understand SA findings from heterogeneous study features for study designs and input data.

Poly- and per-fluoroalkyl substances (PFAS) and volatile methyl siloxanes (VMS) were monitored at 21 sites in the Global Atmospheric Passive Sampling (GAPS) Network. Atmospheric concentrations previously reported from 2009 were compared to concentrations measured at these sites in 2013 and 2015, to assess trends over 7 years of monitoring. Concentrations of the fluorotelomer alcohols (FTOHs) and fluorinated sulfonamides and sulfonamidoethanols (FOSAs and FOSEs) were stable at these sites from 2009 to 2015 with no significant difference (p > 0.05) in concentrations. Elevated concentrations of all the neutral PFAS were detected at the urban sites as compared to the polar/background sites. The perfluorosulfonic acids (PFSAs), meanwhile, saw a significant increase (p < 0.001) in concentrations from 2009 to 2015. The perfluorocarboxylic acids (PFCAs) had elevated concentrations in 2015, however, the difference was not statistically significant (p > 0.05). Concentrations of the PFSAs and the PFCAs were similar at all location types, showing the global reach of these persistent compounds. Concentrations of the cyclic VMS (cVMS) were at least an order of magnitude higher than the linear VMS (lVMS) and the PFAS. Octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) saw a weak significant increase in concentrations from 2009 to 2013 (p < 0.05), however, hexamethylcyclotrisiloxane (D3) had a strong significant decrease in concentrations from 2009 to 2015 (p < 0.01).