Biotransformation of benzene and toluene to catechols by phenol hydroxylase from Arthrobacter sp. W1.

Phenol hydroxylase gene engineered microorganism (PHIND) was used to synthesize catechols from benzene and toluene by successive hydroxylation reaction. HPLC-MS and (1)H NMR analysis proved that the products of biotransformation were the corresponding catechols via the intermediate production of phenols. It was indicated that the main products of toluene oxidation were o-cresol and p-cresol. 3-Methylcatechol was the predominant product for m-cresol biotransformation. Formation rate of catechol (25 µM/min/g cell dry weight) was 1.43-fold higher than that of methylcatechols. It was suggested that phenol hydroxylase could be successfully used to transform both benzene and toluene to catechols by successive hydroxylation.

Comparison of the treatment performance of bio-substrate based and meadow brown soil based subsurface infiltration systems for domestic wastewater treatment.

To foster the practical development of subsurface wastewater infiltration (SWI) systems in China, two systems were implemented on the campus of Shenyang University. The bio-substrate filled SWI (BSWI) and meadow brown soil filled SWI (MSWI) system operated under the same operation mode. According to the 12-month experimental results, the bio-substrate had much higher potential to be a good substrate as compared to the meadow brown soil. The maximum adsorbing capability for NH(4)(+)-N of the bio-substrate was 0.724 mg/g, while for the meadow brown soil, the maximum value was 0.471 mg/g. The amounts of nitrifying and denitrifying bacteria of the BSWI were one order of magnitude higher than that for the MSWI. Ammonia, nitrite and nitrate nitrogen concentrations implied nitrification-denitrification process went well in the BSWI. Moreover, the BSWI system maintained efficient pollutants removal, the mean removal efficiencies were 92.3 ± 1.5%, 96.5 ± 3.1%, 90.0 ± 2.1%, 78.6 ± 1.2%, 91.2 ± 1.1% and 99.7 ± 1.0% for COD, BOD(5), NH(4)(+)-N, TN, TP and SS, respectively. As compared with the MSWI system, pollutant removal efficiencies improved by 26.8 ± 2.3% for NH(4)(+)-N, 33.8 ± 1.7% for TN, 22.4 ± 1.4% for COD, 26.0 ± 3.5% for BOD(5) and 14.7 ± 2.9% for TP, respectively.

Performance evaluation of subsurface wastewater infiltration system in treating domestic sewage.

This study was to investigate domestic treatment efficiency of a subsurface wastewater infiltration (SWI) system over time. The performances of a young SWI system (in Shenyang University, China, fully operated for one year) and a mature SWI system (in Shenyang Normal University, China, fully operated for seven years) under the same operation mode were contrasted through field-scale experiments for one year. The performance assessment for these systems is based on physical and chemical parameters collected. The removal efficiencies within the young system were relatively high if compared with the mature one: for biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), ammonia nitrogen (NH(3)-N) and total phosphorus (TP) were 95.0, 89.1, 98.1, 87.6 and 98.4%, respectively. However, the removal efficiencies decreased over time. The mean removal efficiencies for the mature SWI system were as follows: BOD (89.6%), COD (87.2%), SS (82.6%), NH(3)-N (69.1%) and TP (74.4%). The results indicate that the mature SWI system successfully removed traditional pollutants such as BOD from domestic wastewater. However, the nutrient reduction efficiencies (including NH(3)-N and TP) decreased after seven years of operation of the mature SWI system. Meanwhile, the SWI system did not decrease the receiving surface water quality.

[Ecotoxicity of synthetical musks on wheat (Triticum aestivum) based on seed germination].

With soil culture the ecotoxicological effects of galaxolide (HHCB) and tonalide (AHTN) on the germination of wheat (Triticum aestivum) seeds were investigated. And the influence of these two synthetical musks on the wheat germination rate, inhibition rate of root elongation and inhibition rate of shoot elongation were studied. The results showed that there were no obvious dose-effect relationship between wheat germination rate and concentrations of these two synthetical musks. Lower dose (HHCB < or = 150 mg x kg(-1), AHTN < or = 200 mg x kg(-1)) could accelerate the germination of wheat. Under the test concentrations of synthetical musks, the wheat germination rates treated with HHCB and AHTN were 77.78%-95.56% and 84.44%-97.78%, respectively. There were good dose-effect relationship between inhibition rate of root elongation (or inhibition rate of shoot elongation) and synthetical musks concentrations. The EC50 of HHCB and AHTN based on shoot were 155.84 mg x kg(-1) and 290.58 mg x kg(-1), and were 215.66 mg x kg(-1) and 323.10 mg x kg(-1) based on root from linear model. The EC50 of wheat sensitive positions showed that the toxicity of HHCB was stronger than AHTN.

[Bioturbation of macrobenthos on estuarine sediment].

By using microcosm tracer technique, the bioturbation of macrobenthos Helice tientsinensis, Nereis diversicolor, Bullacta exarata, and Cyclina sinensis on the sediment in Beitang Estuary of Tianjin, China was quantitatively studied. The bioturbation of test macrobenthos had obvious effects on the distribution of the sediment, and the effects differed with the macrobenthos. The disturbed intensity (diffusion coefficient, 10(-3) cm2 x d(-1)) of surface sediment under the effects of the macrobenthos was in order of N. diversicolor (2.95) > H. tientsinensis (1.00) > C. sinensis ( 0.78) > B. exarata. (0.35) > control (0.05), and that of deep sediment was H. tientsinensis (3.10) > N. diversicolor (2.33) > C. sinensis (0.28) > B. exarata (0.15) > control (0.05), which was mainly due to that the macrobenthos were belonged to different functional groups. There was a significant relationship between the bio-volume of test macrobentos and the diffusion coefficient of surface sediment (P < 0.05), suggesting that the bio-volume of macrobenthos could be used as an indicator to predict their bioturbation capacity on esturaine sediment.

[Effects of enhanced dephosphorization in the constructed wetland using water-granulated slag as matrix].

The phosphorus adsorption and desorption effects of water-granulated slag (WGS) were studied. A simulated vertical flow constructed wetland system was constituted using WGS as the main matrix. The influences of hydraulic residence time (HRT) and pollution load on phosphorus removal were investigated. The contributions of phosphorus removal of different horizon layers in up-flow and down-flow matrixes were studied. The results showed that WGS was a kind of adaptive desorption material for wetland due to its high saturated phosphorus adsorptive capacity (3333 mg x kg(-1)). The content of soluble calcium of WGS is 0.084%, which provides a suitable pH (7.54) for microbes and plants growth in wetland. The HRT is in positive correlation with phosphorus removal rate. The phosphorus removal rates decrease 5.9%-4.7% and 2.4%-4.7% when HRT decreases from 1 d to 0.5 d and form 2 d to 1 d, respectively. The phosphorus removal rates exceed 85% at 1 d HRT in WGS wetland. That means the optimized HRT is 1 d, and extending HRT infinitely is not helpful to phosphorus removal. The pollution load is in negative correlation with phosphorus removal rate under the conditions of steady influx concentration. The phosphorus removal rates maintain 85% when the pollution load is from 12.2 g x (m2 x d)(-1) to 36.8 g x (m2 x d)(-1). When the pollution load increases to 48.9 g x (m2 x d)(-1), the phosphorus removal rate decreases to 65% . The phosphorus removal rate exceeds 82% when the pollution load is less than 36.8 g x (m2 x d)(-1). That means higher pollution load will cause the calcium and aluminum active points of phosphorus adsorption shielded, which exist both on matrix surface and in inner pores. The range of optimized pollution load is from 24.5 g x (m2 x d)(-1) to 36.8 g x (m2 x d)(-1). The graduation mode of WGS in top layer and conventional materials in lower layer is helpful to phosphorus removal in vertical flow wetland. The phosphorus adsorptive capacities in up-flow and down-flow unit are 0.17 mg x kg(-1) and 0.05 mg x kg(-1) respectively. The WGS can be changed freely when the saturated adsorption occurs, which will extend the wetland service life.

[Enhanced bio-contact oxidation method to treat petrochemical wastewater by tourmaline].

Aiming at the complexity and poor biochemical degradability of petrochemical wastewater, the effect of tourmaline on bio-contact oxidation method was investigated. The influent and effluent of petrochemical wastewater were analyzed by GC-MS, and the carrier was observed in reactor by scanning electron microscope (SEM). As the loading rates of influent were COD 0.64-0.72 kg/(m3 x d) and NH4(+) -N 0.058-0.072 kg/(m3 x d), the start up of pilot system supported tourmaline were improved, and the removal rate of COD and NH4(+) -N of effluent was increased 8.7% and 6.4%, respectively. Organic pollutants of 100 kinds were detected in influent, mainly including aromatic hydrocarbon, acids, lipids, phenols, alcohols, and alkanes compounds. The removal efficiency of organic pollutant of reactor 1 with tourmaline was higher than reactor 2 without tourmaline. The number of organic pollutant in effluent from reactor 1 and 2 were 14 and 28, respectively. Zoogloea can be observed on carrier supported tourmaline, and the biomass of bacteria was predominant. The efficiency of bio-contact oxidation method on petrochemical wastewater treatment can be enhanced by tourmaline.

[Optimization of LCMSMS determination method for steroid compounds in wastewater and its application in feedlot wastewater].

Taking Solid-Phase Extraction (SPE) as pre-treatment process, a laboratory experiment was conducted by adopting the technology of High Performance Liquid Chromatography-Tandem Mass Spectrometry (HPLC-MSMS) to develop a method to determine the concentrations of 13 steroids in feedlot wastewater. Atmospheric Press Chemical ionization (APCI) source was applied and operated in negative ion model, with the parameters of Chromatography and Spectrometry being optimized. Quasi-molecular ion peak [M + H]+ appeared in the full scan of the first quadrupole of mass spectrometer (Q1) of Testosterone propionate and other 6 steroid compounds, while quasi-molecular ion peak [M + H-H2O]+ appeared in the full scan of Q1 of rest 6 steroid compounds. The linear range of the 9 points calibration curve for the 13 target compounds was determined to be from 1 to 1000 ng x ml(-1), and the calibration curve regression correlation coefficients (R) were always above 0.9990 for all sample batches. The average recovery rate of all target compounds was 83.75%-111.50%, and the methodological stability was determined to be acceptable, with the relative standard deviations between 2.02%-14.21% (n=6). Except that the limit of detection (LOD) of Mestradiol and Oestriol was higher than 15 ng x ml(-1), all the other target compounds had a LOD lower than 5 ng x ml(-1). In the determination of real samples from feedlot wastewater, the developed method represented a good profile to all target compounds at different concentrations in each stage of treatment.

[Principal physicochemical properties of artificial soil composed of sewage sludge stabilized by fly ash].

The pH, nutrients and heavy metals of stabilized sewage sludge were investigated by mixing municipal sewage sludge with alkaline fly ash and mine tailing. The results indicate that water-holding capacity of artificial soil III (FA : SS = 1 : 1) and II (FA : SS = 2 : 1) treatments were significantly higher than that of CK (brown meadow soil), while that of the IV (FA : SS = 1 : 2) treatment was similar to CK; The nutrients contents (organic matter, N, P, K) of stabilized sewage sludge were up to a high fertilizer level. Moreover, with decrease of the ratio of fly ash to sewage sludge, the nutrient content of artificial soils increased. Except total Ni content of III (FA : SS = 1 : 1) treatment was high (187.67 mg x kg(-1)), Cd, Pb, Cu, Zn, and Cr for all artificial soil treatments were all significant lower than control standards for pollutants in sludges and fly ash from Agricultural use (GB 4284-84, GB 8173-87).

[Impact of benzo [a] pyrene the expression of mitochondrion-encoded genes in the earthworm Eisenia fetida].

The earthworm Eisenia fetida's benzo [a] pyrene (BaP) exposure experiments were carried out in artificial soil according to ISO 11268-1:1993. And then the upregulated and downregulated subtractive cDNA libraries were constructed by Clontech PCR-Select cDNA Subtration Kit. From the BaP exposure upregulated subtractive cDNA library, several cDNA segments matched mitochondrion-encoded genes were found, including cytochrome c oxidase subunit I (CO I), subunit II (CO II), subunit Ill (CO III), NADH dehydrogenase subunit 1 (NDH1), and ATP synthase subunit 6. The result indicated BaP and the subsequent oxidative stress disturbed the expression of mitochondrion-encoded genes, and this was potential biomarker for oxidative stress following xenobiotic exposure.

[Low dose benzo(a)pyrene up-regulated the transcription of HSP70 and HSP90 in Eisenia fetida].

To search for the molecular biomarkers of sub-lethal polycyclic aromatic hydrocarbons (PAHs)-contamination of soil, the subtractive cDNA libraries of earthworm Eisenia fetida exposed to benzo(a)pyrene (BaP) in artificial soil were constructed by suppression subtractive hybridization. After sequencing and analyzing with basic local alignment search tool (BLAST), two clones matching heat shock protein 70 k Da (HSP70) and one clone matching heat shock protein 90 k Da (HSP90) were isolated from the up-regulated library, and subsequently, the up-regulation of HSP70 and HSP90 was verified by real-time PCR in E. fetida exposed to 0.1 mg x kg(-1) and 1.0 mg x kg(-1) BaP. It was indicated that these two newly identified HSPs in E. fetida were the potential molecular biomarkers for soil contamination monitoring.

[Application and prospect of infrared spectroscopy in environmental science].

With the application of Fourier transform infrared spectrograph and the development of chemical metrology, Fourier transform infrared spectroscopy (FTIR) has become a kind of beneficial tool and means for analyzing samples. Especially with its strong identifying ability, exact determining results and fast response function, the application of FTIR method to environmental science has been popularized gradually. At present, people are launching applied study based on the specific property of FTIR in their corresponding field. Therefore, the present paper mainly introduced the current situation of study, progress and application of infrared spectroscopy in liquid, solid and gas environment state monitoring and qualitative analysis in the nearly past qualitative 10 years. In addition, the future development direction in environmental science is also discussed for its helpfulness in that field.

[Effects of low dosage pyrene pollution on biochemical characters of earthworm (Eisenia fetida) in soil].

By the method of artificial soil pollution, an exposure experiment with different concentrations of pyrene (0, 60, 120, 240, 480, 960 microg x kg(-1)) was conducted to determine the cytochrome P450 and MDA contents and the glutathione-S-transferase (GST), superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities in earthworm gut after exposure for 1, 3, 7 and 14 days. The results indicated that within the range of test pyrene concentrations, all the biochemical indices tested differed in their sensitivity to pyrene toxicity, among which, P450 content and GST and SOD activities were most sensitive, followed by POD and CAT activities, while MDA content did not show any obvious response. Exposure duration had stronger effects than exposure dosage. In diagnosing the ecotoxicity of soil pollutant, it could be necessary to use a combined multi-time and multi-index diagnostic method to enhance the sensitivity and effectiveness of the indices adopted.

[Effects of EDTA on lead accumulation in Tagetes patula and Salvia spendens].

Pot experiments were conducted to investigate the effects of EDTA on the Pb availability in rhizospheric soil and the Pb accumulation in Tagetes patula and Salvia spendens. The results showed that 7 days after applying EDTA (3.0 mmol x kg(-1)) into soil, the concentration of ammonium acetate (1 mol x L(-1)) -extracted Pb in rhizospheric soil increased significantly (P < 0.01), and the Pb content in T. patula and S. spendens leaves reached to 2415.88 and 1083.68 mg x kg(-1), being 61.36 and 5.37 times of the control, respectively. The Pb content also had a marked increase in T. patula and S. spendens stems, but had a slight decrease in their roots.

[Sorption-desorption behaviors of Cd2+ and Pb2+ in different pollution load soils].

With batch method, this paper studied the sorption-desorption behaviors of Cd and Pb in soils with heavy, medium, and slight pollution loads. The results showed that the soil with slight pollution load had a high sorption capacity of Cd2+ and Pb2+ than the other two. For the three test soils, the isothermal curve of Cd2+ sorption fitted Freundlich equation better, while that of Pb2+ sorption could be well described with Langmuir equation and Freundlich equation. Two-constant equation was the best model to describe the sorption kinetics of Cd2+ and Pb2+, Elovich equation was the second, and the worst was first-order dynamics equation. The desorption lag of Pb2+ was more obvious than that of Cd2+, and the desorption rates of adsorbed Cd2+ and Pb2+ were higher in the soil with heavy pollution load. The relationships between the desorbed and the initial absorbed amounts of Cd2+ and Pb2+ fitted quadratic equation. In test soils, the desorption rates of Cd2+ and Pb2+ increased with increasing initial concentrations of Cd2+ and Pb2+, but decreased with increasing duration of desorpion.

[Effects of furadan on soil enzyme activity].

By using simulation method, this paper studied the effects of furadan on the activities of soil urease, invertase and alkaline phosphatase, with the affecting factors investigated. The results showed that after adding furadan into soil, soil urease activity was decreased first but increased then, indicating that the ecotoxicity of furadan was reduced gradually. When the concentration of furadan was less than 0.3%, soil urease, invertase and alkaline phosophatase were all activated, and in some soil samples, a significant positive correlation was observed between soil invertase activity and furadan concentration, suggesting that soil invertase activity could be used as an indicator for the soil pollution caused by furadan. It was concluded that the quality of soil and ecological environment would be kept safe under low concentrations of furadan (< or = 0.3%).

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture.

Soil contaminated with heavy metals cadmium (Cd) and lead (Pb) is hard to be remediated. Phytoremediation may be a feasible method to remove toxic metals from soil, but there are few suitable plants which can hyperaccumulate metals. In this study, Cd and Pb accumulation by four plants including sunflower (Helianthus annuus L.), mustard (Brassica juncea L.), alfalfa (Medicago sativa L.), ricinus (Ricinus communis L.) in hydroponic cultures was compared. Results showed that these plants could phytoextract heavy metals, the ability of accumulation differed with species, concentrations and categories of heavy metals. Values of BCF (bioconcentration factor) and TF (translocation factor) indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals. Changes on the biomass of plants, pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures. Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals, such as pH and Eh regulations, and so forth.

[Dose-response relationships between endogenous phytohormones of high plant and concentrations of fluoranthene and benzo(a)pyrene in soils].

By means of indoor pot experiment, three phytohormones, gibberellic acid (GA3), zeatin and zeatin riboside (Z&ZR), abscisic acid (ABA) of wheat ( Triticum acstivnm) were measured under the stress of fluoranthene and benzo(a)pyrene in meadow brown soil singlely and combinedly. The results indicated that significant dose-response relationship was observed between ABA contents and the concentrations of single fluoranthene and combined pollution of fluoranthene and benzo(a)pyrene, and ABA content responded more intensive to single fluoranthene than to combined treatment. When treated with 16 mg x kg(-1) single fluoranthene, ABA content increased by 198% as compared with control. Significant effects on GA3 content of combined treatment were also observed, but GA3 responded insensitively to single fluoranthene and benzo(a)pyrene treatment. Z&ZR responded intensively under stress of both single and combined pollution, and the inducible effects were accordant. It can be concluded that endogenous phytohormones play an important role in indicating PAHs polluted soil, and the sensitivity of the three phytohormones responded to fluoranthene and benzo(a)pyrene single and combined pollution is in the sequence: Z&ZR > ABA > GA3.

[Sorption-desorption behavior of Cd2 + and Pb2+ in rhizosphere and bulk soil].

Sorption-desorption behavior of Cd2+ and Pb2+ in the rhizosphere and bulk soil of wheat was studied by the batch method. The results indicated that the sorption capacity of rhizosphere soil to Cd2+ and Pb2+ was higher than that of bulk soil. Isothermal curves of Cd2+ sorption by rhizosphere and bulk soil fitted Freundlich equation well. Isothermal sorption process of Pb2+ could be well described by Langmuir equation and Freundlich equation. Two-constant equation was the best model to describe the sorption kinetics of Cd2+ and Pb2+ followed by Elovich equation, and the worst model was first-order dynamics equation. There was sorption-desorption hysteresis of Cd2+ and Pb2+. The desorptive rates of Cd2+ and Pb2+ in rhizosphere soil was lower than that of bulk soil. The relationship between desorptive quantity of Cd2+ and Pb2+ in two soils and the initial sorptive quantity coincided with quadratic equation. The desorptive rates of Cd2+ and Pb2+ in two soils increased with the higher initial concentrations of Cd2+ and Pb2+ in the treatments, and decreased with the increasing desorptive time. Two-constant equation was the optimal model to describe the desorptive kinetics of Cd2+ and Pb2+ in the two soils, and followed by Elovich equation, while the first-order dynamics equation fitted not well.

[Heavy metals removal and its kinetics in contaminated soil under effects of EDTA washing].

In this paper, batch experiments were made to examine the effects of different EDTA concentrations, pH, and washing duration of EDTA on the removal of heavy metals from contaminated soil. An empirical model was employed to describe the kinetics of heavy metals dissolution and desorption, and the form changes of test heavy metals were determined before and after EDTA washing. The results showed that EDTA was effective to the removal of heavy-metals from contaminated soil. At 0.1 mol x L(-1) and pH 7 of EDTA and within 24 h, the removal rate of test heavy metals was the maximum, being 89.14% for Cd, 34.78% for Pb, 14.96% for Cu, and 45.14% for Zn. The mass transfer coefficient was in the order of Cd > Zn > Pb > Cu. Sequential fractionations of treated and untreated soil samples showed that EDTA was effective in removing the exchangeable, carbonate and oxide forms of Cd, Pb, Zn and Cu, but ineffective for the organic and residual forms of test heavy metals.