Comparison of Four Amendments for Arsenic and Cadmium Combined Contaminated Soil.

Arsenic (As) and cadmium (Cd) are common soil pollutants whose opposing geochemical behaviors must be taken into account in the development of cost-effective, environmentally friendly remediation strategies. In this study, a pot experiment with lettuce and a field experiment with wheat were performed to examine the impacts of zeolite, biochar, MnO2, zero-valent iron (ZVI) individually and in binary combinations thereof on As-Cd pollution. The results of the pot experiment showed that biochar, MnO2 and ZVI had good passivation effects on As and Cd when provided individually, but the effects of a combination of 0.2% ZVI/0.5% biochar or 0.2% MnO2/0.5% ZVI were even better. These amendments were further investigated in a field experiment, which confirmed the positive effect of 0.2% MnO2/0.5% ZVI. Therefore, ZVI/biochar and MnO2/ZVI mixtures may offer effective solutions to the remediation of farmland soil contaminated with both As and Cd.

Layer-by-layer assembly of bio-inspired borate/graphene oxide membranes for dye removal.

Dye wastewater is harmful to the ecological environment because of its potential biological toxicity, teratogenicity, carcinogenicity, and mutagenicity. We fabricated a layered graphene oxide (GO) membrane through layer-by-layer (LBL) self-assembly. We used borate to crosslink with GO on a polyethyleneimine (PEI)-coated hydrolyzed polyacrylonitrile (hPAN) support. Fourier transform infrared (FTIR) spectrometry, Raman spectra, and x-ray photoelectron spectroscopy (XPS) confirmed the presence of a crosslinking reaction. The dynamic thermomechanical analysis (DMA) results indicated that the introduction of borate can significantly improve the mechanical properties of the membrane. The Young's modulus, ultimate tensile strength, and proportional limit of borate that was assembled twice as the outermost layer were increased by 110.81%, 62.37%, and 53.72%, respectively, as compared to those of a single-layered GO membrane. Moreover, the pure water fluxes of the layered GO membrane did not obviously decrease with an increase in the number of layers. The flux of the membrane with an outermost layer of borate was greater than that of the previous GO layer. The salt and dye rejection of the membranes was augmented with an increase in the number of layers. For the GO membrane assembled three times, rejection to methyl orange (MO), methylene blue (MB), NaCl, MgCl2, and MgSO4 reached 74.02%, 88.56%, 14.55%, 27.50%, and 41.95%, respectively. The use of borate as an inorganic crosslinker can avoid the environmental pollution caused by organic agents, and improve the mechanical properties as well as the filter capability of the layered GO membrane. Therefore, this study presents a novel method of membrane preparation for dye removal.

Study on the lifetime of photocatalyst by photocatalytic membrane reactors (PMR).

The continuously photocatalytic degradation of methyl orange (MO) was carried out using a photocatalytic membrane reactor (PMR). The lifetime, cause of deactivation, and regeneration of Degussa P25 titanium dioxide (TiO2) were investigated. The photocatalyst was deactivated when the concentration of MO in the effluent of the PMR was stable. To characterize the lifetime of the photocatalyst, we applied g MO/g TiO2. The lifetime of the photocatalyst during the photocatalytic degradation of 10 mg/L MO was 3.71 times that of 5 mg/L MO. Changing the hydraulic retention time of the PMR from 0.75 to 3 h prolonged the lifetime of the photocatalyst. Deactivation of the photocatalyst was not due to pore blocking by the reactant (MO) or intermediate products. The surface adsorption of MO and the reaction intermediates deactivated the catalyst. The spent catalysts were regenerated after washing with methanol and hydrogen peroxide (H2O2) and then treated with heat. H2O2 treatment generated the highest regeneration rate, because H2O2 is a strong oxidizing agent that oxidized the deposited species on the surface of the photocatalyst.

To Approach or to Avoid? Motivation Differentially Mediates the Effect of Hardiness on Depressive Symptoms in Chinese Military Personnel.

OBJECTIVE: To investigate the mediation effect of approach/avoidance motivation between hardiness and depressive symptoms. METHODS: Cross-sectional design was utilized. Two independent samples of military servicemen (G1: military personnel in the Armed Forces; G2: Chinese army military cadets) (n1 = 98, n2 =140) were sampled and investigated. The assessment tools of hardiness scale (DRS), behavioral activation and inhibition scales (BAS/BIS), and Center for Epidemiological Survey-Depression Scale (CES-D)/Beck Depression Inventory (BDI) were used. General linear model was conducted to examine the predictive role of hardiness (DRS) and motivation (BAS/BIS) on depressive symptoms (CES-D or BDI). The mediating role of BAS/BIS between hardiness and depressive symptoms was examined. RESULTS: (1) Across army soldiers and military medical university cadets, hardiness (ß=-0.394, P<0.001) and behavioral inhibition (ß=0.297, P<0.001) significantly predicted depressive symptoms. (2) For soldiers only, behavioral inhibition mediated the significant association between hardiness and depressive symptoms (ß=-0.043, SE=0.027, 95%CI=-0.130~-0.008). (3) For cadets only, behavioral activation-Drive significantly predicted depressive symptoms (ß=-0.237, P=0.012), and hardiness operates through behavioral activation-Drive to influence depressive symptoms (ß=-0.057, SE=0.036, 95%CI=-0.151~-0.078). CONCLUSION: Individuals who are low in hardiness and behavioral activation-Drive and who are high in behavioral inhibition showed more severe depressive symptoms. The relationship between hardiness and depressive symptoms was mediated by behavioral activation-Drive in cadets and behavioral inhibition in soldiers. The proposed model offers a useful approach for the development of hardiness training programs to alter approach/avoidance motivation in the military context. Future training program of hardiness could lay more emphasis on promotion of perseverance in pursuing goals in hardy individuals, which may in turn improve active coping.

[Determination of diethyl aminoethyl hexanoate residues in apples by gas chromatography-mass spectrometry combined with improved QuEChERS].

A method was developed for the determination of diethyl aminoethyl hexanoate (DA-6) residues in apples by gas chromatography-mass spectrometry (GC-MS) combined with improved QuEChERS. The samples were first extracted with warm water, then, the extract was subjected to liquid-liquid re-extraction with dichloromethane, followed by rotary evaporation concentration. The residues were cleaned up with primary secondary amine (PSA). The analytes were separated on an HP-5 capillary column and detected using an EI source in the SIM mode. The recoveries ranged from 74.1% to 84.2% at three spiked levels, with relative standard deviations (RSDs) between 1.5% and 4.1%. The limit of detection and limit of quantification were 0.0024 mg/kg and 0.008 mg/kg, respectively. The developed method is sensitive, and practically applicable for the determination of DA-6 residues in apple samples.

Removal mechanisms for extremely high-level fluoroquinolone antibiotics in pharmaceutical wastewater treatment plants.

Pharmaceutical wastewater treatment plants (PWWTPs) receive industrial effluents from the plant that contain extremely high levels of antibiotics and are regarded as one of the major sources of antibiotics in the environment. Two PWWTPs have been selected in Zhejiang Province, China, to assess the removal mechanisms of fluoroquinolone antibiotics (FQs). PWWTP A uses activated sludge with biocarriers in a moving bed biofilm reactor in anoxic and aerobic units, and PWWTP B uses biological units under anaerobic, aerobic, and anoxic conditions. The wastewater samples and solid samples (sludge and suspended solid matter) were analyzed using solid-phase extraction and ultra-performance liquid chromatography-mass spectrometry. Ofloxacin (OFX) was detected in each stage of PWWTP A, and enrofloxacin and ciprofloxacin were detected in PWWTP B. The concentrations of FQs ranged from 0.32 µg/L to 5.7 mg/L. Although the FQs were largely removed in the biological units (94.5 to 99.9%), large amounts were still discharged in the final effluent (up to 88.0 ± 7.0 µg/L) and dewatered sludge (up to 0.85 ± 0.24 mg/kg). Mass balance analyses of samples from PWWTP A indicated that biodegradation (93.8%) was the major mechanism responsible for the removal of OFX, whereas the contribution of sorption by sludge (0.79%) was less significant, deviating from the findings of most similar studies. Using linear analysis and correlation analysis, we found that the log10 values of the FQ concentration in the sludge were positively related with the log10 values of the equilibrium concentration in water (C w ). These relationships can be described by a Freundlich-like equation. However, these relationships were negative when the C w values were high. Our preliminary explanation is that the equilibrium C w plays an important role in controlling the sorption behavior of FQs in activated sludge.

[Simultaneous determination of ten antibiotics in pharmaceutical wastewater using ultra-high performance liquid chromatography-tandem mass spectrometry].

A simultaneous analytical method was established for ten selected antibiotics from three categories in pharmaceutical wastewater with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The water samples were enriched and cleaned-up by solid phase extraction cartridges. The types of solid phase extraction cartridges and eluents were optimized by comparing the recoveries of the analytes in water samples under different conditions. The target compounds were separated on an Agilent C18 column (75 mmx 2.1 mm, 2.7 µm) with the mobile phases of acetonitrile and 0.2% (v/v) formic acid aqueous solution, and then determined by electrospray ionization mass spectrometry (ESI-MS). The results showed that the calibration curves were linear in the range of 0.1-1000 µg/L (r2>0.995). The limits of detection (LODs, S/N≥3) and the limits of quantification (LOQs, S/N≥10) of the ten compounds were 0.07-4.37 ng/L and 0.22-14.55 ng/L, respectively. The recovery experiments were performed with samples spiked in the range of 0.002-40 µg/L. The recoveries of the target compounds were in the range of 50.4%-114.1% (RSDs≤9.89%, n=3). Based on this analytical method, the raw and treated sewage samples from a pharmaceutical manufacturer wastewater treatment plant in Jiangsu Province were analyzed. Three compounds were detected in the samples from different sewage treatment units in the range of 0.46-1033.60 µg/L. It shows that the method is accurate, reliable, highly sensitive and can be used to analyze the water samples of pharmaceutical wastewater treatment plant containing aminoglycosides, spiramycin and fluoroquinolones antibiotics.

Pollution characteristics and environmental risk assessment of typical veterinary antibiotics in livestock farms in Southeastern China.

Scientific interest in pollution from antibiotics in animal husbandry has increased during recent years. However, there have been few studies on the vertical exposure characteristics of typical veterinary antibiotics in different exposure matrices from different livestock farms. This study explores the distribution and migration of antibiotics from feed to manure, from manure to soil, and from soil to vegetables, by investigating the exposure level of typical antibiotics in feed, manure, soil, vegetables, water, fish, and pork in livestock farms. A screening environmental risk assessment was conducted to identify the hazardous potential of veterinary antibiotics from livestock farms in southeast China. The results show that adding antibiotics to drinking water as well as the excessive use of antibiotic feed additives may become the major source of antibiotics pollution in livestock farms. Physical and chemical properties significantly affect the distribution and migration of various antibiotics from manure to soil and from soil to plant. Simple migration models can predict the accumulation of antibiotics in soil and plants. The environmental risk assessment results show that more attention should be paid to the terrestrial eco-risk of sulfadiazine, sulfamethazine, sulfamethoxazole, tetracycline, oxytetracycline, chlorotetracycline, ciprofloxacin, and enrofloxacin, and to the aquatic eco-risk of chlorotetracycline, ciprofloxacin, and enrofloxacin. This is the first systematic analysis of the vertical pollution characteristics of typical veterinary antibiotics in livestock farms in southeast China. It also identifies the ecological and human health risk of veterinary antibiotics.

Landfill CH4 oxidation by mineralized refuse: effects of NH4(+)-N incubation, water content and temperature.

Mineralized refuse, excavated from a municipal solid waste (MSW) landfill that had been closed for more than 10 years, was incubated in livestock wastewater for 150 d to accumulate ammonia-oxidizing bacteria and also co-oxidize methane (CH(4)). The extent of CH(4) oxidation and carbon dioxide (CO(2)) emissions from the incubated mineralized refuse (IMR) were investigated to assess its applicability as a bio-cover material at landfill sites for minimizing total greenhouse gas emission equivalents. From the initial 200 mg nitrogen (N) kg(-1) incubated for 120 h, the nitrate-N content produced in the IMR was twice (P<0.05) that of the untreated original mineralized refuse (OMR) and 3.81 (P<0.05) times that of soil. For an initial CH(4) concentration of approximately 10% by volume in the headspace, CH(4) consumption and net emission of CO(2) from the soil, IMR and OMR all agreed well with first-order and zero-order kinetics models for a 120-h incubation (R(2)=0.667 and R(2)=0.995, respectively). Similar to N turnover, the rate of consumption of CH(4) by the mineralized refuse was some 50.0% higher than for soil (P<0.05). Based on the net rate of CO(2) generation, the CH(4) oxidation rate by IMR was 14.2% (P>0.05) greater than for OMR and 56.1% (P>0.05) higher than for soil. Variation of water content and temperature produced substantially higher CH(4) consumption rates by IMR than by either OMR or soil. After treatment by livestock wastewater, the CH(4) oxidation capacity of mineralized refuse was moderately improved, due to the enhancement of CH(4) adsorption by retained suspended solids and the subsequent co-oxidation by the accumulated ammonia-oxidizing bacteria. By correlation analysis for the three experimental materials, CH(4) oxidation rate was significantly correlated with specific surface area and organic matter content (P<0.05), and was positively correlated with CO(2) generation, NH(4)(+)N nitrification and NO(3)(-)N generation rate (P>0.05).

Water pollution control technology and strategy for river-lake systems: a case study in Gehu Lake and Taige Canal.

The Taoge water system is located in the upstream of Taihu Lake basin and is characterized by its multi-connected rivers and lakes. In this paper, current analyses of hydrology, hydrodynamics and water pollution of Gehu Lake and Taige Canal are presented. Several technologies are proposed for pollution prevention and control, and water environmental protection in the Taihu Lake basin. These included water pollution control integration technology for the water systems of Gehu Lake, Taige Canal and Caoqiao River. Additionally, river-lake water quality and quantity regulation technology, ecological restoration technology for polluted and degraded water bodies, and water environmental integration management and optimization strategies were also examined. The main objectives of these strategies are to: (a) improve environmental quality of relative water bodies, prevent pollutants from entering Gehu Lake and Taige Canal, and ensure that the clean water after the pre-treatment through Gehu Lake is not polluted before entering the Taihu Lake through Taige Canal; (b) stably and efficiently intercept and decrease the pollution load entering the lake through enhancing the river outlet ecological system structure function and water self-purifying capacity, and (c) designate Gehu Lake as a regulation system for water quality and water quantity in the Taoge water system and thus guarantee the improvement of the water quality of the inflow into Taihu Lake.

Evaluation of municipal sewage treatment systems for pollutant removal efficiency by measuring levels of micropollutants.

In order to evaluate the municipal sewage treatment systems used at Harbin municipal sewage treatment plant for their pollutant removal efficiency, raw sewage and effluent samples at different treatment stages from the sewage treatment systems were taken, priority pollutants (PPs) were identified and quantified using gas chromatography-mass spectrometry (GC-MS) and inductively coupled plasma-atomic emission spectrograph (ICP-AES). The test results indicated that there were one hundred and fifty species of organic pollutants identified in the raw sewage sample, and only ten species of PPs in all the sewage samples. The levels of dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), di-n-octyl phthalate (DnOP) in the sewage samples were 0.779-0.111 microg l(-1), 1.977-0.022 microg l(-1), 6.411-2.194 microg l(-1) and 7.152-2.953microg l(-1), respectively, and most of these phthalate esters (PAEs) were removed through anaerobic/aerobic (A/O) process; The levels of alachlor, acetochlor, atrazine were 0.074-0.021 microg l(-1), 0.160-0.096 microg l(-1) and 0.238-0.184 microg l(-1), respectively, and the total removal efficiency of atrazine was poorest through the sewage treatment systems. The levels of Cu, Cr, Se, Hg, Ni and Zn were 0.0030-0.2327 mg l(-1). It is therefore concluded from these results that the sewage treatment systems were efficient in removing most of the organic and inorganic compounds in this study, and so, the discharged effluent could cause little of the secondary pollution of the aquatic environment.