A novel isolated bacterium Rhodococcus sp. YSPW03 was able to reduce high concentrations (up to 700 mg L⁻¹) of perchlorate using acetate as electron donor. Perchlorate reduction rate increased from 2.90 to 11.23 mg L⁻¹ h⁻¹ with increasing initial acetate concentration from 100 to 2000 mg L⁻¹, leading to complete removal of perchlorate (100 mg L⁻¹) within 9 h. The bacterium also promoted complete reduction of high perchlorate concentrations (500 and 700 mg L⁻¹) at 2000 mg L⁻¹ of acetate within 48 and 96 h, respectively. Under semi-continuous reactor operation, efficient reduction on varied perchlorate concentrations (80–700 mg L⁻¹) was performed by the bacterium in presence of acetate (600–6000 mg L⁻¹) over 140 days. The highest perchlorate reduction rate of 280 mg L⁻¹ day⁻¹ was observed with an initial perchlorate concentration of 570 mg L⁻¹ at day 34. Dissolved chloride ions of 1000 mg L⁻¹ in the semi-continuous reactor (SCR) completely inhibited the biological perchlorate reduction. The findings of this study will help improve the perchlorate bioreactor design and determine the optimal conditions to maximize the perchlorate reduction efficiency.

Nowadays, nitrogen (N) deposition has become a growing global concern due to urbanization activities increasing the large amount of reactive N in the atmosphere. However, it remains unclear whether urbanization affects the composition and main sources of N deposition in rapidly urbanizing areas such as in China. One-year measurement of wet inorganic N deposition was conducted using ion-exchange resin (IER) columns in the range of 260 km from urban to rural areas in the Pearl River Delta (PRD) region, south China. An increasing pattern of wet inorganic deposition along the urbanization gradient was observed and it increased in the order: rural (15.26 ± 0.20 kg N ha⁻¹ year⁻¹) < suburban/rural (21.45 ± 3.73 kg N ha⁻¹ year⁻¹) < urban (31.16 ± 0.44 kg N ha⁻¹ year⁻¹) < urban/suburban sites (34.15 ± 5.73 kg N ha⁻¹ year⁻¹). Nitrate N (NO₃⁻–N) accounted for 53.5–79.1 % of total wet inorganic N deposition, indicating a significant negative correlation with distance from the urban core. Based on moss δ¹⁵N-values the main source of NO₃⁻–N was considered to be emitted from vehicles. Our results demonstrate that urbanization has large impacts on the regional pattern of wet inorganic N deposition. Thus, controlling NOx emission, especially vehicle emission will become an effective strategy for N pollution abatement in China.

P-Nitrophenol (PNP) is considered to be one of nitrophenol derivatives of diesel exhaust particles. PNP is a major metabolite of some organophosphorus compounds. PNP is a persistent organic pollutant as well as one of endocrine-disrupting compounds. Consequently, bioaccumulation of PNP potentiates toxicity. The objectives of the current study were to assess in vivo adverse effects of long-term low doses of PNP exposure on reproductive system during development stage. Twnety-eight-day-old male Japanese quails were orally administered different doses of PNP (0, 0.01, 0.1, 1 mg/kg body weight) daily for 2.5 months. Testicular histopathology, hormones, caspase-3 (CASP3), and claudin-1 (CLDN1) tight junction protein, as well as plasma hormones were analyzed. The results revealed that long-term PNP exposure caused testicular histopathological changes such as vacuolation of spermatogenic cell and spermatocyte with significant testicular and cloacal gland atrophy. PNP activated CASP3 enzyme that is an apoptosis-related cysteine peptidase. Besides, it disrupted the expression of CLDN1. Furthermore, a substantial decrease in plasma concentrations of luteinizing hormone (LH) and testosterone was observed after 2 and 2.5 months in the PNP-treated groups. Meanwhile, the pituitary LH did not significantly change. Site of action of PNP may be peripheral on testicular development and/or centrally on the hypothalamic–pituitary–gonadal axis through reduction of pulsatile secretion of gonadotrophin-releasing hormone. Consequently, it may reduce the sensitivity of the anterior pituitary gland to secrete LH. In conclusion, PNP induced profound endocrine disruption in the form of hormonal imbalance, induction of CASP3, and disruption of CLDN1 expression in the testis. Hence, it may hinder the reproductive processes.

Four light-duty vehicles (two diesel, one flex-fuel, and one gasoline vehicle) were tested as part of an intercomparison exercise of the world-harmonized light-duty vehicle test procedure (WLTP) aiming at measuring real-time ammonia emissions from the vehicles’ raw exhaust at the tailpipe. The tests were conducted in the Vehicle Emission Laboratory (VELA) at the European Commission Joint Research Centre (EC-JRC), Ispra, Italy. HORIBA, CGS, and the Sustainable Transport Unit of the Joint Research Centre (JRC) took part in the measurement and analysis of the four vehicles’ exhaust emissions over the world-harmonized light-duty vehicle test cycle class 3, version 5.3 using a HORIBA MEXA 1400 QL-NX, a CGS BLAQ-Sys, and the JRC Fourier transform infrared spectrometer, respectively. The measured ammonia concentrations and the emission profiles revealed that these three instruments are suitable to measure ammonia from the vehicles’ raw exhaust, presenting no significant differences. Furthermore, results showed that measurement of ammonia from the vehicle exhaust using online systems can be performed guaranteeing the reproducibility and repeatability of the results. While no ammonia was detected for any of the two diesel vehicles (even though, one was equipped with a selective catalytic reduction system), we report average ammonia emission factors 8–10 mg/km (average concentrations 20–23 ppm) and 10–12 mg/km (average concentrations 22–24 ppm) for the flex-fuel and gasoline vehicles, respectively.

Alkylphenol ethoxylates (APEs) and brominated flame retardants (BFRs) are known to be bio-accumulative, persistent, and endocrine disruptors and can cause adverse health effects in animals and humans. In this study, environmental samples were collected from sites along the Vaal River, South Africa in order to determine the concentrations of APEs and BFRs in water, sediment, and fish samples. The highest concentrations of these pollutants were observed from discharge of the Rietspruit WWTW. Measurable levels of both APEs and BFRs were observed with APEs exhibiting higher concentrations than BFRs in all the matrices. The concentrations observed for APEs and BFRs were as follows: 1.00–3.85 μg/L APEs, 0.09–0.26 μg/L PBDEs, ND- 0.14 PBBs and 0.51–1.77 μg/L HBCD for water samples; 47–63 ng/g lipid APEs, 3.24–12.4 ng/g lipid PBB, 4.63–33 ng/g lipid PBDEs and 10–13 ng/g lipid HBCD for fish; and 40–184 ng/g (wet weight (ww)) APEs, 2.93–5.9 ng/g (ww) PBB, 10–24 ng/g (ww) PBDEs, and 15–52 ng/g (ww) HBCD for sediment samples. The concentrations of APEs and BFRs in water samples were found to be in the range with the results reported in the literature while the concentration in fish and sediment were lower than the concentrations reported in other studies.

Particles in vehicle exhaust plumes in underground parking lots have adverse health effects due to the enclosed environment in which they are released and the temperature difference between the tailpipe and ambient environment; at the same time, particle coagulation might be obvious near the tailpipe in an underground parking lot. In the present study, airflow and temperature fields were calculated using the Realizable k-ε model, and the Eulerian particle transport model was selected in the numerical simulation of particle concentration dispersion. Polydisperse thermal coagulation due to Brownian collisions was employed to calculate the particle coagulation. The results show that particle coagulation rate and half-time were significant within 1 m from the tailpipe. The variations in the particle coagulation rate and half-time were similar, but their directions were opposite. Air exhaust time was nearly four times longer than averaged half-time and 40 times longer than minimum half-time. The peak particle diameter increased approximately 1.43 times due to coagulation. A double particle concentration at the tailpipe caused the fourfold rise in the particle coagulation rate in the distance ranging less than 1 m from the tailpipe. An increase in exhaust velocity at the tailpipe could shorten the obvious range of particle coagulation along the centerline of the tailpipe from 1 to 0.8 m in the study.

Recent studies suggest that the ecotoxicity of engineered nanoparticles (ENPs) is dependent upon the treatment of ENPs in suspensions (e.g. sonication or use of solvents) and on the mode of exposure to test organisms. We conducted several bioassays with Daphnia magna in order to determine how adverse effects of TiO₂nanoparticles (n-TiO₂) are influenced by experimental set-up. Several treatments were applied, including three test media, several treatments of n-TiO₂suspensions (stirring, sonication) and different exposure modes (exposure duration and volume of test suspension). No adverse effects were observed when D. magna were exposed to 50 mL of suspension, regardless of TiO₂concentration (up to 250 mg/L) and exposure duration. Conversely, adverse effects were observed when D. magna were exposed to 2 mL of suspension for 96 h with a 50 % effect concentration EC₅₀values ranging from 32 mg/L to 82 mg/L. Test media had no significant influence on the outcome of all treatments. For a better mechanistic understanding of the experimental set-up at which adverse effects were observed, the particle size of n-TiO₂in the test media was characterized throughout the test duration. These measurements revealed a fast and strong agglomeration with a secondary particle size in the order of magnitude of micrometers. Our study describes how the effects of n-TiO₂on D .magna are influenced by the duration of exposure and volume of media, highlighting the need for standardization of experimental methods.

The tobacco has the genetic potential to remove toxic metals from the soil. To develop hyperaccumulating tobacco plants, distant hybridization between tobacco (Nicotiana tabacum L.), a high-biomass crop, and Perilla frutescens (L.) Britt var. frutescens, a newfound Cd-hyperaccumulator species, was carried out using a novel method viz. pollination following grafting. Their hybrid nature was preliminarily confirmed by phenotype, isozyme pattern, random amplified polymorphic DNA (RAPD) and metabolites analysis. About 120 putative F₂hybrids derived from the cross-combination [(N. sylvestris Speg. & Comes rootstock + N. tabacum L. var. 78–04 scion) × P. frutescens (L.) Britt var. frutescens] were then subjected to up to 300 μM CdCl₂in hydroponic conditions for 10 days. Results showed five seedlings were more resistant to Cd than female parent and accumulated 314.6 ± 99.9 mg kg⁻¹Cd in their aerial biomass, which was 5.7 times greater than that in "78-04" tobacco (47.2 ± 3.56 mg kg⁻¹) (P ≤ 0.05). Two of these seedlings exceeded male parent P. frutescens in the Cd concentration of shoots and reached 424 and 396 mg kg⁻¹, which was 13 % and 6 % greater for that of perilla (374.2 ± 10.38 mg kg⁻¹), respectively. Compared with parents, two other F₂hybrids tended to accumulate more Cd in the root with bioconcentration factor (BCF) 7.05 and 5.17, respectively. Only one hybrid showed lower Cd concentration but transferred Cd more effectively from the root to the shoot than parents and other F₂hybrids, with the maximum translocation factor (TF) value 1.37. These indicated that the introduction of P. frutescens genes could obviously enhance the cadmium tolerance and accumulation of superior individuals.

A growing body of evidence has investigated the association between maternal exposure to PM₂.₅(particulate matter with aerodynamic diameter 2.5 μm) during pregnancy and adverse pregnancy outcomes. However, the results of those studies are not consistent. To synthetically quantify the relationship between maternal exposure to PM₂.₅during pregnancy and pregnancy outcomes (the change in birth weight, low birth weight (LBW), preterm birth (PTB), small for gestational age (SGA), and stillbirth), a meta-analysis of 25 published observational epidemiological studies that met our selection criteria was conducted. Results suggested a 10 μg/m³increase in PM₂.₅was positively associated with LBW (odds ratio (OR) = 1.05; 95 % confidence interval (CI), 1.02–1.07), PTB (OR = 1.10; 95 % CI, 1.03–1.18), and SGA (OR = 1.15; 95 % CI, 1.10–1.20) based on entire pregnancy exposure, and pooled estimate of decrease in birth weight was 14.58 g (95 % CI, 9.86–19.31); however, there was no evidence of a statistically significant effect of per 10 μg/m³increase in PM₂.₅exposure on the risk of stillbirth (OR = 1.18; 95 % CI, 0.69–2.04). With respect to three different gestation periods, no significant risks were found in PTB, stillbirth, and the first trimester on the change of birth weight with a 10 μg/m³increase in PM₂.₅. In this study, a comprehensive quantitative analysis of the results show that PM₂.₅can increase the risk of LBW, PTB, and SGA; pregnant women need to take effective measures to reduce PM₂.₅exposure.

The present study aimed to examine whether the physical reworking of sediments by harrowing would be suitable for favouring the hydrocarbon degradation in coastal marine sediments. Mudflat sediments were maintained in mesocosms under conditions as closer as possible to those prevailing in natural environments with tidal cycles. Sediments were contaminated with Ural blend crude oil, and in half of them, harrowing treatment was applied in order to mimic physical reworking of surface sediments. Hydrocarbon distribution within the sediment and its removal was followed during 286 days. The harrowing treatment allowed hydrocarbon compounds to penetrate the first 6 cm of the sediments, and biodegradation indexes (such as n-C₁₈/phytane) indicated that biodegradation started 90 days before that observed in untreated control mesocosms. However, the harrowing treatment had a severe impact on benthic organisms reducing drastically the macrofaunal abundance and diversity. In the harrowing-treated mesocosms, the bacterial abundance, determined by 16S rRNA gene Q-PCR, was slightly increased; and terminal restriction fragment length polymorphism (T-RFLP) analyses of 16S rRNA genes showed distinct and specific bacterial community structure. Co-occurrence network and canonical correspondence analyses (CCA) based on T-RFLP data indicated the main correlations between bacterial operational taxonomic units (OTUs) as well as the associations between OTUs and hydrocarbon compound contents further supported by clustered correlation (ClusCor) analysis. The analyses highlighted the OTUs constituting the network structural bases involved in hydrocarbon degradation. Negative correlations indicated the possible shifts in bacterial communities that occurred during the ecological succession.