The identification of airborne bacteria has traditionally been performed by retrieval in culture media, but the bacterial diversity in the air is underestimated using this method because many bacteria are not readily cultured. Advances in DNA sequencing technology have produced a broad knowledge of genomics and metagenomics, which can greatly improve our ability to identify and study the diversity of airborne bacteria. However, researchers are facing several challenges, particularly the efficient retrieval of low-density microorganisms from the air and the lack of standardized protocols for sample collection and processing. In this study, we tested three methods for sampling bioaerosols — a Durham-type spore trap (Durham), a seven-day recording volumetric spore trap (HST), and a high-throughput 'Jet' spore and particle sampler (Jet) — and recovered metagenomic DNA for 16S rDNA sequencing. Samples were simultaneously collected with the three devices during one week, and the sequencing libraries were analyzed. A simple and efficient method for collecting bioaerosols and extracting good quality DNA for high-throughput sequencing was standardized. The Durham sampler collected preferentially Cyanobacteria, the HST Actinobacteria, Proteobacteria and Firmicutes, and the Jet mainly Proteobacteria and Firmicutes. The HST sampler collected the largest amount of airborne bacterial diversity. More experiments are necessary to select the right sampler, depending on study objectives, which may require monitoring and collecting specific airborne bacteria.

N-ethyl perfluorooctane sulfonamide (N-EtFOSA) is an important perfluorooctanesulfonate (PFOS) precursor (PreFOS) which is used in sulfluramid. The present work studied the uptake, translocation and metabolism of N-EtFOSA in wheat (Triticum aestivum L.), soybean (Glycine max L. Merrill) and pumpkin (Cucurbita maxima L.) by hydroponic exposure. Except for parent N-EtFOSA, its metabolites of perfluorooctane sulfonamide acetate (FOSAA), perfluorooctane sulfonamide (PFOSA), PFOS, perfluorohexane sulfonate (PFHxS) and perfluorobutane sulfonate (PFBS) were detected in the roots and shoots of all the three plant species examined. This suggested that plant roots could take up N-EtFOSA from solutions efficiently, and translocate to shoots. A positive correlation was found between root concentration factors (RCFs) of N-EtFOSA and root lipid content. Much higher proportion of N-EtFOSA transformation products in plant tissues than in the solutions suggested that N-EtFOSA could be in vivo metabolized in plant roots and shoots to FOSAA, PFOSA and PFOS, and other additional shorter-chain perfluoroalkane sulfonates (PFSAs), including PFHxS and PFBS. The results suggested that plants had biotransformation pathways to N-EtFOSA that were different than those from microorganisms and animals. This study provides important information about the uptake and metabolism of PreFOSs in plants.

Organic UV stabilizers and UV filters are applied to industrial materials and cosmetics worldwide. In plastics they prevent photo-induced degradation, while in cosmetics they protect human skin against harmful effects of UV radiation. This study reports on the occurrence and distribution of organic UV stabilizers and UV filters in the surface sediment of the Chinese Bohai and Yellow Seas for the first time. In total, 16 out of 21 analyzed substances were positively detected. Concentrations ranged from sub-ng/g dw to low ng/g dw. The highest concentration of 25 ng/g dw was found for octocrylene (OC) in the Laizhou Bay. In the study area, characteristic composition profiles could be identified. In Korea Bay, the dominating substances were OC and ethylhexyl salicylate (EHS). All other analytes were below their method quantification limit (MQL). Around the Shandong Peninsula, highest concentrations of benzotriazole derivatives were observed in this study with octrizole (UV-329) as the predominant compound, reaching concentrations of 6.09 ng/g dw. The distribution pattern of UV-329 and bumetrizole (UV-326) were related (Pearson correlation coefficient r > 0.98, p « 0.01 around the Shandong Peninsula), indicating an identical input pathway and similar environmental behavior.

Continuous haze monitoring was conducted from 12:00 3 April to 12:00 8 April 2016 in Beijing, China to develop a more detailed understanding of spring haze characteristics. The PM₂.₅ concentration ranged from 6.30 to 165 μg m⁻³ with an average of 63.8 μg m⁻³. Nitrate was the most abundant species, accounting for 36.4% of PM₂.₅, followed by organic carbon (21.5%), NH₄⁺ (19.3%), SO₄²⁻ (18.8%), and elemental carbon (4.10%), indicating the key role of nitrate in this haze event. Species contribution varied based on the phase of the haze event. For example, sulfate concentration was high during the haze formation phase, nitrate was high during the haze, and secondary organic carbon (SOC) had the highest contribution during the scavenging phase. The secondary transition of sulfate was influenced by SO₂, followed by relative humidity (RH) and Oₓ (O₃+NO₂). Nitrate formation occurred in two stages: through NO₂ oxidation, which was vulnerable to Oₓ; and by the partitioning of N (+5) which was susceptible to RH and temperature. SOC tended to form when Oₓ and RH were balanced. According to hourly species behavior, sulfate and nitrate were enriched during haze formation when the mixed layer height decreased. However, SOC accumulated prior to the haze event and during formation, which demonstrated the strong contribution of secondary inorganic aerosols, and the limiting contribution of SOC to this haze case. Investigating backward trajectories showed that high speed northwestern air masses following a straight path corresponded to the clear periods, while southwesterly air masses which traversed heavily polluted regions brought abundant pollutants to Beijing and stimulated the occurrence of haze pollution. Results indicate that the control of NO₂ needs to be addressed to reduce spring haze. Finally, the correlation between air mass trajectories and pollution conditions in Beijing reinforce the necessity of inter-regional cooperation and control.

Ambient air pollution has been associated with adverse respiratory outcomes, especially among children with asthma. This study reports on associations between daily ambient air pollutant concentrations and the respiratory symptoms of schoolchildren living in Durban, South Africa. This city is Africa's busiest port and a key hub for imported crude oil and exported refined petroleum and petrochemical products, and it experiences a mixture of air pollutants that reflects emissions from industry, traffic and biomass burning. Children in four communities in the highly industrialized southern portion of the city were compared to children of similar socio-economic profiles living in the north of the city. One school was selected in each community. A total of 423 children were recruited. Symptom logs were completed every 1.5–2 h over 3-week period in each of four seasons. Ambient concentrations of NO₂, NO, SO₂, CO, O₃, PM₂.₅ and PM₁₀ were measured throughout the study. Generalized estimating equation (GEE) models were used to estimate odds ratios (ORs) and assess lag effects (1–5 days) using single pollutant (single lags or distributed lags) models. Concentrations of SO₂ and NOₓ were markedly higher in the south, while PM₁₀ did not vary. Significant increase in the odds ratios of cough were identified for the various lags analyzed. The OR of symptoms was further increased among those living in the south compared to the north. In conclusion, in this analysis of over 70,000 observations, we provide further evidence that exposure to PM₁₀, SO₂, NO₂ and NO is associated with significantly increased occurrence of respiratory symptoms among children. This was evident for cough, shortness of breath, and chest tightness, across the four pollutants and for different lags of exposure. This is the first study describing these changes in sub-Saharan Africa.

Photocatalysis was recognised as a suitable process for the photoabatement of atmospheric pollutants. The photooxidation mechanism on TiO2 has been widely studied. However, recent studies demonstrated that the very often-assumed photooxidation intermediated by the hydroxyl radical cannot explain all the experimental observations. Indeed, this study contributes for a new understanding of NO photooxidation. First, the adsorption equilibrium isotherms of NO, NO2 and H2O on the photocatalyst, Aeroxide® P25 from Evonik Industries, were obtained. Also, the concentration of hydroxyl radicals was determined by photoluminescence. A comprehensive design of experiments was then followed; NO conversion and selectivity were obtained as a function of the relative humidity, irradiance, NO inlet concentration and residence time, following a response surface methodology (RSM). These results were then used to discuss the photooxidation mechanism of NO.

Although the hepatotoxicity of thifluzamide in zebrafish has been characterized, its toxic mechanisms have not been fully explored. The present study demonstrated that thifluzamide damaged the zebrafish liver and endoplasmic reticulum (ER). In addition, thifluzamide significantly changed the expression of genes encoding antioxidant proteins and increased the malondialdehyde (MDA) content, leading to oxidative damage in zebrafish liver. Additionally, the autophagic ultrastructure was observed by transmission electron microscopy (TEM), and LC3-I/LC3-II conversion was obviously upregulated under western blotting (WB) measurements, verifying that autophagy was induced by thifluzamide. Moreover, the activities of Caspase-3 and Caspase-9 were obviously decreased, indicating that apoptosis was inhibited in adult zebrafish exposed to a higher concentration of thifluzamide. In summary, oxidative damage and autophagy but not apoptosis under ER injury might lead to the hepatotoxicity of thifluzamide in zebrafish. Our findings provide a new mechanistic insight into the toxicity of thifluzamide in zebrafish.

Environmental exposure of fish to steroid hormones through wastewater and agricultural runoff may pose a health risk. Thus far, ecotoxicological studies have largely been focused on the disruption of the sex hormone system, but additional effects have been poorly investigated. Here we report on the effects of a series of different natural and synthetic steroid hormones on the locomotor behavior and the transcriptional levels of core clock genes in zebrafish eleuthero-embryos (Danio rerio). Of the 20 steroids analyzed, progestins and corticosteroids, including progesterone and cortisol, significantly decreased the locomotor activities of eleuthero-embryos at concentrations as low as 16 ng/L, while estrogens such as 17β-estradiol led to an increase. Consistently, progestins and corticosteroids displayed similar transcriptional effects on core clock genes, which were remarkably different from those of estrogens. Of these genes, per1a and nr1d2a displayed the most pronounced alterations. They were induced upon exposure to various progestins and corticosteroids and could be recovered using the progesterone receptor/glucocorticoid receptor antagonist mifepristone; this, however, was not the case for estrogens and the estrogen receptor antagonist 4-hydroxy-tamoxifen. Our results suggest that steroid hormones can modulate the circadian molecular network in zebrafish and provide novel insights into their mode of actions and potential environmental risks.

Microplastic and microfiber pollution has been documented in all major ocean basins. Microfibers are one of the most common microparticle pollutants along shorelines. Over 9 million tons of fibers are produced annually; 60% are synthetic and ∼25% are non-synthetic. Non-synthetic and semi-synthetic microfibers are infrequently documented and not typically included in marine environment impact analyses, resulting in underestimation of a potentially pervasive and harmful pollutant. We present the most extensive worldwide microparticle distribution dataset using 1-liter grab samples (n = 1393). Our citizen scientist driven study shows a global microparticle average of 11.8 ± 24.0 particles L−1 (mean ± SD), approximately three orders of magnitude higher than global model predictions. Open ocean samples showed consistently higher densities than coastal samples, with the highest concentrations found in the polar oceans (n = 51), confirming previous empirical and theoretical studies. Particles were predominantly microfibers (91%) and 0.1–1.5 mm in length (77%), a smaller size than those captured in the majority of surface studies. Using μFT-IR we determined the material types of 113 pieces; 57% were classified as synthetic, 12% as semi-synthetic, and 31% as non-synthetic. Samples were taken globally, including from coastal environments and understudied ocean regions. Some of these sites are emerging as areas of concentrated floating plastic and anthropogenic debris, influenced by distant waste mismanagement and/or deposition of airborne particles. Incorporation of smaller-sized microfibers in oceanographic models, which has been lacking, will help us to better understand the movement and transformation of synthetic, semi-synthetic and non-synthetic microparticles in regional seas and ocean basins.

Effects of sulfadiazine and ciprofloxacin on the occurrence of free-living and particle-associated opportunistic pathogens in bulk water of simulated drinking water distribution systems (DWDSs) were investigated. It was found that sulfadiazine and ciprofloxacin greatly promoted the occurrence of opportunistic pathogens including Pseudomonas aeruginosa, Legionella pneumophila, Mycobacterium avium and its broader genus Mycobacterium spp., as well as the amoebae Acanthamoeba spp. and Hartmanella vermiformis, in bulk water of DWDSs. Moreover, sulfadiazine and ciprofloxacin exhibited much stronger combined effects on the increase of these opportunistic pathogens. Based on the analysis of the antibiotic resistance genes (ARGs) and extracellular polymeric substances (EPS), it was verified that EPS production was increased by the antibiotic resistant bacteria arising from the effects of sulfadiazine/ciprofloxacin. The combined effects of sulfadiazine and ciprofloxacin induced the greatest increase of EPS production in DWDSs. Furthermore, the increased EPS with higher contents of proteins and secondary structure β-sheet led to greater bacterial aggregation and adsorption. Meanwhile, large numbers of suspended particles were formed, increasing the chlorine-resistance capability, which was responsible for the enhancement of the particle-associated opportunistic pathogens in bulk water of DWDSs with sulfadiazine/ciprofloxacin. Therefore, sulfadiazine and ciprofloxacin promoted the occurrence of particle-associated opportunistic pathogens in bulk water of DWDSs due to the role of EPS produced by the bacteria with ARGs.