Removal of chloramphenicol and resistance gene changes in electric-integrated vertical flow constructed wetlands.

The performance of an electric-integrated vertical flow constructed wetland (E-VFCW) for chloramphenicol (CAP) removal, changes in microbial community structure, and the fate of antibiotic resistance genes (ARGs) were evaluated. CAP removal in the E-VFCW system was 92.73% ± 0.78% (planted) and 90.80% ± 0.61% (unplanted), both were higher than the control system which was 68.17% ± 1.27%. The contribution of anaerobic cathodic chambers in CAP removal was higher than the aerobic anodic chambers. Plant physiochemical indicators in the reactor revealed electrical stimulation increased oxidase activity. Electrical stimulation enhanced the enrichment of ARGs in the electrode layer of the E-VFCW system (except floR). Plant ARGs and intI1 levels were higher in the E-VFCW than in the control system, suggesting electrical stimulation induces plants to absorb ARGs, reducing ARGs in the wetland. The distribution of intI1 and sul1 genes in plants suggests that horizontal transfer may be the main mechanism dispersing ARGs in plants. High throughput sequencing analysis revealed electrical stimulation selectively enriched CAP degrading functional bacteria (Geobacter and Trichlorobacter). Quantitative correlation analysis between bacterial communities and ARGs confirmed the abundance of ARGs relates to the distribution of potential hosts and mobile genetic elements (intI1). E-VFCW is effective in treating antibiotic wastewater, however ARGs potentially accumulate.

Enhanced biodegradation of fluoroquinolones and the changes of bacterial communities and antibiotic-resistant genes under intermittent electrical stimulation.

In this study, an anaerobic-aerobic coupling system under intermittent electrical stimulation was used to improve the biodegradation of synthetic wastewater containing fluoroquinolones (FQs). The effect of electrical stimulation on FQ removal performance is more pronounced with appropriate voltage and hydraulic retention time. In addition, the combination of anaerobic-anodic and aerobic-cathodic chambers is more conducive to improving the removal efficiency of FQs. Under 0.9 V, the removal efficiencies of ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin were significantly improved in the anaerobic-anodic and aerobic-cathodic system. The contribution of the anaerobic/aerobic anodic chambers to FQ removal was greater than that of the anaerobic/aerobic cathodic chambers. Electrical stimulation selectively enriched electroactive bacteria related to biodegradation (Desulfovibrio and Terrimonas), antibiotic-resistant bacteria (Atopobium and Neochlamydia), and nitrifying bacteria (SM1A02 and Reyranella). This study indicated the potential effectiveness of intermittent electrical stimulation in treating fluoroquinolone-containing wastewater in a biofilm reactor. However, electrical stimulation led to an increase in mobile genetic elements , induced horizontal gene transfer and enriched resistant bacteria, which accelerated the spread of antibiotic-resistant genes (ARGs) in the system, indicating that the diffusion of ARGs remains a challenge.

Levels, source apportionment, and risk assessment of polycyclic aromatic hydrocarbons in vegetable bases of northwest China.

Dietary consumption of contaminated vegetables is the main route of human exposure to polycyclic aromatic hydrocarbons (PAHs). However, there is a lack of research on PAHs in vegetables from northwest China. In this study, the concentrations, sources, and risk assessment of PAHs in the soil and vegetables of Urumqi, an urbanized city in Xinjiang, China, were investigated. The total concentrations of 16 PAHs in soil and vegetable samples ranged 10.58-77.20 and 93.7-1071.8 ng/g, with average values of 2.86 and 242.76 ng/g, respectively. Among vegetable samples, the concentrations were in the order: leafy vegetables (299.08 ng/g) > fruits (192.65 ng/g) > vegetable roots (152.05 ng/g). The source apportionment of PAHs was identified using positive matrix factorization. The primary sources of PAHs in soil samples are oil spills, traffic emissions, coal combustion, and coke combustion. The main sources of PAHs in vegetable samples are oil spills and burning of grass, wood, coal, and coke. In soil samples, the ecological risk caused by PAHs is at a safe level, and the incremental lifetime cancer risks (ILCRs) of ingestion exposure exceed 1.0 × 10-6, which will pose potential risks to human body. The ILCRs of vegetable samples revealed that all groups had potential risks from onion and cabbage consumption (ILCRs > 1.0 × 10-6). In particular, adult women had a higher risk of cancer (ILCRs > 1.0 × 10-4). These results emphasize the importance of combating PAHs pollution in vegetable bases.

Levels, sources, and risk assessment of PAHs residues in soil and plants in urban parks of Northwest China.

Polycyclic aromatic hydrocarbons (PAHs) will be ingested by people through different ways to threaten their health during play, so the environmental quality of the park directly affects the health of tourists and residents. Using eight typical parks in Urumqi in Northwest China as the study area, we used GC-MS to detect the PAHs content in the park surface soil and 10 common plants in the park in different seasons. The results showed that the content of PAHs in park soil in the summer was 5-6 times that in the winter, and the monomer PAHs in some park soil sampling points were higher than the soil pollution risk screening value. And the contamination level at these sampling sites was also higher compared to other sampling sites. In summer, the plants with high PAHs content in leaves are short herbs, while in winter, they are tall arbors. The PAHs of the park soil are mainly composed of high-cyclic aromatic hydrocarbons, and are mainly of traffic origin. The proportion of low-ring aromatic hydrocarbons in the winter was significantly higher than that in the summer. The source of PAHs in plants in summer is similar to that in soil, but the source of PAHs in plants in winter is more complex. The toxicity equivalent concentration method values of soil PAHs in South Park, Zhiwu Park, Shihua Park and Toutunhe Park were higher than that in other parks. The lifetime carcinogenic risk (ILCRs) values of some sampling points in these four parks in the summer were relatively high. The average ILCRs of adults and children in all parks reached a low-risk level in summer. The carcinogenic risk in children is much higher than that of adults.

Impact of Voltage Application on Degradation of Biorefractory Pharmaceuticals in an Anaerobic-Aerobic Coupled Upflow Bioelectrochemical Reactor.

Diclofenac, ibuprofen, and carbamazepine are frequently detected in the environment, where they pose a threat to organisms and ecosystems. We developed anaerobic-aerobic coupled upflow bioelectrochemical reactors (AO-UBERs) with different voltages, hydraulic retention times (HRTs), and types of electrode conversion, and evaluated the ability of the AO-UBERs to remove the three pharmaceuticals. This study showed that when a voltage of 0.6 V was applied, the removal rate of ibuprofen was slightly higher in the system with aerobic cathodic and anaerobic anodic chambers (60.2 ± 11.0%) with HRT of 48 h than in the control systems, and the removal efficiency reached stability faster. Diclofenac removal was 100% in the 1.2 V system with aerobic anodic and anaerobic cathodic chambers, which was greater than in the control system (65.5 ± 2.0%). The contribution of the aerobic cathodic-anodic chambers to the removal of ibuprofen and diclofenac was higher than that of the anaerobic cathodic-anodic chambers. Electrical stimulation barely facilitated the attenuation of carbamazepine. Furthermore, biodegradation-related species (Methyloversatilis, SM1A02, Sporomusa, and Terrimicrobium) were enriched in the AO-UBERs, enhancing pharmaceutical removal. The current study sheds fresh light on the interactions of bacterial populations with the removal of pharmaceuticals in a coupled system.

Pollution assessment and health risk evaluation of eight (metalloid) heavy metals in farmland soil of 146 cities in China.

Heavy metals are the most important indicator for farmland soil; however, in China, few provincial and national scales of studies have been done on heavy metals. Herein, by retrieving published studies, we calculated the spatial distribution characters and evaluated the health risks of Cu, Zn, Cd, Ni, Pb, Cr, As, and Hg in the farmland soil of 146 cities in China. Results showed that (1) the range (mean) values of eight (metalloid) heavy metals were as follows in mg/kg: Cu 0.236-251.015 (44.604), Zn 0.151-1547.060 (154.203), Cd 0.014-39.100 (1.497), Ni 0.709-554.420 (41.968), Pb 0.327-495.400 (55.143), Cr 0.078-333.510 (70.093), As 0.836-60.000 (12.207), and Hg 0.008-12.190 (0.371). The coefficient of variation values of Cu, Cr, and As displayed moderate variation, and Zn, Cd, Ni, Pb, and Hg displayed high variation (142.148-364.960%). (2) the Igeo values of As, Cu, Cd, Ni, Zn, Cr, Pb, and Hg were - 4.329 to 1.837, - 7.166 to 2.888, - 3.378 to 8.070, - 5.831 to 3.780, - 9.527 to 3.797, - 10.120 to 1.866, - 6.899 to 3.667, and - 3.681 to 6.966, respectively; in many cities, there was some degree of heavy metal pollution of the farmland soil such as Zn in Pingdu, Pb in Huludao, and Hg in Tongguan, Funshun, Huludao, and Qinglong (Igeo > 3); there were no obvious spatial patterns of Cr, Ni, and As, and Zn, Cu, but Cd, Ni, Pb, and Hg mainly located in some cities in the southwest, central or eastern parts of China. (3) Health risk assessment showed that with the exception of Cd, Cr, and As by the respiration route and Ni, Cr, and As through skin exposure, the average amount of daily exposure of the eight (metalloid) heavy metals all showed values for children > adults, and the HQ and HI values were all lower than 1.0, indicating noncarcinogenic risks; calculation of carcinogenic risks showed there were no carcinogenic risks for As, Cr, Ni, and Cd; however, the value for Cr was the maximum and contributed 98.505% of the total.

A study of synchronous measurement of liable phosphorous and iron based on ZrO-Chelex (DGT) in the sediment of the Chaiwopu Lake, Xinjiang, Northwest China.

The water-sediment interface of lakes is an important and unique area of the water environment; the geochemical behavior of nutrients in this area has a significant impact on the quality of the water environment and ecosystems, especially in shallow lakes. However, most studies do not provide direct in situ evidence for this in shallow lakes in arid regions; in order to explore the coupling relationship between phosphorus (P) and iron (Fe) in a sediment profile, we conducted a high-resolution analysis of liable Fe and P in sediments taken from the Chaiwopu Lake using ZrO-Chelex thin film diffusion gradient technology (ZrO-Chelex DGT). The results show that (1) the vertical spatial distribution trend of the liable P and Fe in the sediments from each sampling site is essentially similar. The contents of the liable P and Fe ranged from 0.004-0.125 mg/L and 0.050-0.190 mg/L, respectively, and the synchronous distribution of the micro-interface concentration reflects the coupling relationship between them. (2) The correlation analysis of the liable P and Fe concentrations showed that there were significant linear correlations between them (P < 0.05, bilateral). (3) The diffusion fluxes of P and Fe were - 51.76~65.12 µg (m2 d)-1 and - 451.27~457.06 µg (m2 d)-1, respectively, and were shown to be negative at the sediment-water interface for most of the samples, which showed that P and Fe were released from the overlying water into the sediments. (4) This research showed that the diffusive fluxes at the different sites are quite different, which indicates that the phosphorus and iron pollution in the sediments of the Chaiwopu Lake is affected by exogenous inputs. There was no significant correlation between P release flux and pH, ORP, conductivity (EC), the TDS of the overlying water, or the pH, salinity (Ca2+, Mg2+), and nutrient (organic matter) content of the sediment. The release flux of Fe is affected by the pH of the sediment. The results of this study provide references for the research of elements in the water-sediment interface of shallow lakes in arid regions, as well as other areas.

Membrane-Protected Molecularly Imprinted Polymer for the Microextraction of Indole-3-butyric Acid in Mung Bean Sprouts.

Based on the hollow fiber protected molecularly imprinted polymer, a micro-solid-phase extraction (µ-SPE) method was developed and applied for the analysis of indole-3-butyric acid in mung bean sprouts by high-performance liquid chromatography. The extraction conditions of the µ-SPE method were optimized using L9(34) orthogonal, and optimum conditions were found as follows: pH of sample solution was 2.0, chloroform was the organic solvent for embedding the µ-SPE bars, and acetonitrile was the desorption solvent. In addition, the extraction time was 80 min, desorption time was 5 min, stirring speed was 800 rpm, and concentration of NaCl was 10%. Under the optimum conditions, a standard curve was established for IBA, with a correlation coefficient of 0.9999. After extraction with phosphate buffer solution (pH = 9.0), successful pretreatment of mung bean sprouts was achieved by the µ-SPE method. The limit of detection was 0.075 mg/kg, and the recoveries were found to be in the range of 88.9-106.4%. This method is simple, environmentally friendly, and can be used for the determination of indole auxin contents in green bean sprouts quickly and accurately.

Pollution assessment and health risks evaluation of (metalloid) heavy metals in urban street dust of 58 cities in China.

In this research, we conducted a statistical analysis of ten (metalloid) heavy metals, including Cu, Hg, Cd, Zn, Pb, As, Ni, Cr, Co, and Mn in urban dust of 58 cities in China from 2000 to 2018, and then we analyzed the statistic characters, pollution statue, and health risks of ten heavy metals. Results showed that (1) the maximum (average) values of ten (metalloid) heavy metals in the street dust of 58 Chinese cities all exceeded Chinese background values, and there were obvious differences in contents of heavy metals of Hg, Zn, Co, Cr, and As between industry cities and common cities. A provincial spatial distribution analysis revealed large variations of distributions of heavy metals Cu, Zn, Pb, and Cr, which distributed in cities mainly located in southern, central, and eastern China, ranging from relatively low to high levels, while Ni, Co, and Mn mainly distributed in southern and central China. This is mainly associated with the mining of the cities. (2) Igeo analysis showed that there was no obvious Ni, Mn, or Co pollution in street dust, while the other tested heavy metals had a range of low to high levels of pollution, in particular, seven metals among them had low to extremely strong levels of pollution (Igeo values between 0 and 7.154), and the average Igeo values were in the following order: Cd > Hg > Zn > Pb > Cu > As>Cr > Mn > Co > Ni. (3) Health risks evaluation showed that of the three exposure ways, the HQing from hand-mouth intake was the most common exposure route for both children and adults, especially for children, followed by skin absorption and respiration ways. This research showed that the HI value for children was higher than 1, indicative of no carcinogenic risks, while the HI values for both male and female were lower than 1, indicative of carcinogenic risks; calculation of carcinogenic risk through respiratory route showed that the risks of five elements were within the range 10-6-10-4, indicative of carcinogenic risk, among which Cr accounting exceeded 90% of total, which needs to be paid more attention to.