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.

[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.

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.

Adsorption characteristics of copper, lead, zinc and cadmium ions by tourmaline.

The adsorption characteristics of heavy metals: Cu(II), Pb(II), Zn(II) and Cd(II) ions on tourmaline were studied. Adsorption equilibrium was established. The adsorption isotherms of all the four metal ions followed well Langmuir equation. Tourmaline was found to remove heavy metal ions efficiently from aqueous solution with selectivity in the order of Pb(II)>Cu(II)>Cd(II)>Zn(II). The adsorption of metal ions by tourmaline increased with the initial concentration of metal ions increasing in the medium. Tourmaline could also increase pH value of metal solution. -The maximum heavy metal ions adsorbed by tourmaline was found to be 78.86, 154.08, 67.25, and 66.67 mg/g for Cu(II), Pb(II), Zn(II) and Cd(R), respectively. The temperature (25-55 degrees C) had a small effect on the adsorption capacity of tourmaline. Competitive adsorption of Cu(II), Pb(II), Zn(II) and Cd(II) ions was also studied. The adsorption capacity of tourmaline for single metal decreased in the order of Pb>Cu>Zn >Cd and inhibition dominance observed in two metal systems was Pb>Cu, Pb>Zn, Pb>Cd, Cu>Zn, Cu>Cd, and Cd>Zn.

Removal of heavy metals from a contaminated soil using tartaric acid.

This study reports the feasibility of remediation of a heavy metal (HM) contaminated soil using tartaric acid, an environmentally-friendly extractant. Batch experiments were performed to test the factors influencing remediation of the HM contaminated soil. An empirical model was employed to describe the kinetics of HM dissolution/desorption and to predict equilibrium concentrations of HMs in soil leachate. The changes of HMs in different fractions before and after tartaric acid treatment were also investigated. Tartaric acid solution containing HMs was regenerated by chestnut shells. Results show that utilization of tartaric acid was effective for removal of HMs from the contaminated soil, attaining 50%-60% of Cd, 40%-50% of Pb, 40 %-50% of Cu and 20%-30% of Zn in the pH range of 3.5-4.0 within 24 h. Mass transfer coefficients for cadmium (Cd) and lead (Pb) were much higher than those for copper (Cu) and zinc (Zn). Sequential fractionations of treated and untreated soil samples showed that tartaric acid was effective in removing the exchangeable, carbonate fractions of Cd, Zn and Cu from the contaminated soil. The contents of Pb and Cu in Fe-Mn oxide fraciton were also significantly decreased by tartaric acid treatment. One hundred milliliters of tartaric acid solution containing HMs could be regenerated by 10 g chestnut shells in a batch reactor. Such a remediation procedure indicated that tartaric acid is a promising agent for remediation of HM contaminated soils. However, further research is needed before the method can be practically used for in situ remediation of contaminated sites.

Temporal-spatial distribution and variability of cadmium contamination in soils in Shenyang Zhangshi irrigation area, China.

Heavy metal contamination in soils has been of wide concern in China in the last several decades. The heavy metal contamination was caused by sewage irrigation, mining and inappropriate utilization of various agrochemicals and pesticides and so on. The Shenyang Zhangshi irrigation area (SZIA) in China is a representative area of heavy metal contamination of soils resulting from sewage irrigation for about 30 years duration. This study investigated the spatial distribution and temporal variation of soil cadmium contamination in the SZIA. The soil samples were collected from the SZIA in 1990 and 2004; Cd of soils was analyzed and then the spatial distribution and temporal variation of Cd in soils was modelled using kriging methods. The kriging map showed that long-term sewage irrigation had caused serious Cd contamination in topsoil and subsoil. In 2004, the Cd mean concentrations were 1.698 and 0.741 mg/kg, and the maxima 10.150 and 7.567 mg/kg in topsoils (0-20 cm) and subsoils (20-40 cm) respectively. These values are markedly more than the Cd levels in the second grade soil standard in China. In 1990, the Cd means were 1.023 and 0.331 mg/kg, and the maxima 9.400 and 3.156 mg/kg, in topsoils and subsoils respectively. The soil area in 1990 with Cd more than 1.5 mg/kg was 2701 and 206.4 hm(2) in topsoils and subsoils respectively; and in 2004, it was 7592 and 1583 hm(2), respectively. Compared with that in 1990, the mean and maximum concentration of Cd, as well as the soil area with Cd more than 1.5 mg/kg had all increased in 2004, both in topsoils and subsoils.

Influences of phosphate nutritional level on the phytoavailability and speciation distribution of cadmium and lead in soil.

A pot experiment was conducted to examine the influence of phosphate levels on the phytoavailability and speciation distribution of cadmium (Cd), lead (Pb) in soil. Spring wheat (Triticum aestivum L.) was selected as the tested plant. There were 5 phosphate fertilizer(Ca(H2PO4)2) levels including 0, 50, 100, 200, and 400 mg P2O5/kg soil, marked by PO, P1, P2, P3, and P4, respectively. CdCl2 x 2.5H2O and Pb(NO3)2 were added to soil as the following levels: Cd + Pb = 25+0, 0+1000, and 25+1000 mg/kg, marked by T1, T2, and T3, respectively. The results showed that the P fertilizer promoted the dry weight of wheat in all treatments and alleviated the contamination induced by Cd and Pb. With increasing levels of the additional P fertilizer, Cd concentration in different parts (root, haulm, chaffand grain) of wheat decreased at the P1 level at first and then increased. The soluble plus exchangeable (SE) fraction of Cd in soil decreased at the P1 level and then increased from P2 to P4 levels. The moderate P fertilizer reduced the phytoavailability of Cd. The application of P could obviously restrain the uptake of Pb by wheat and there were significantly negative correlations between the levels of P and the uptake of Pb. Phosphorus supply resulted in a decrease in the SE fraction of Pb and there was a significantly negative correlation between the levels of P and the SE fraction of Pb in soil. All the levels of the P fertilizer in this experiment could reduce the phytoavailability of Pb. Thus, it is feasible to apply the P fertilizer (Ca(H2PO4)2) to Pb contaminated soils. However, the levels of P application should be restricted in case that redundant P may increase the phytoavailability of Cd.

Phytotoxicity assessment of phenanthrene, pyrene and their mixtures by a soil-based seedling emergence test.

Seedling emergence tests were conducted in a meadow brown soil using five plant species (i.e., Chinese cabbage, green onion, tomato, turnip and wheat) to determine the phytotoxicity of phenanthrene, pyrene and their mixtures. The soil was amended with up to 1000 mg/kg soil of phenanthrene or 600 mg/kg soil of pyrene. Seedling emergence and root growth were measured. The results indicated that root elongation was more sensitive than seedling emergence. Root length decreased with increasing phenanthrene or pyrene concentrations( p < or = 0.05). Phenanthrene was more phytotoxic than pyrene. The lowest observable adverse effect concentration (LOAEC) was 10 mg/kg for phenanthrene when tested with green onion, and 50 mg/kg for pyrene when tested with wheat. Among the five species, wheat was found to be the most sensitive. When amended jointly at or below their respective LOAEC, phenanthrene and pyrene produced a synergistic toxic effect.

Rapid ecotoxicological assessment of heavy metal combined polluted soil using canonical analysis.

Quick, simple to perform, and cheap biomarkers were combined in a rapid assessment approach to measure the effects of metal pollutants, Cu, Cd, Pb and Zn in meadow burozem on wheat. Analysis of orthogonal design showed that the significant zinc factor indicated both the inhibition rate of shoot mass and that of root elongation were affected by zinc (P < 0.05 and P < 0.01, respectively). The first toxicity canonical variable (TOXI), formed from the toxicity data set, explained 49% of the total variance in the toxicity data set; the first biological canonical variable (BIOL) explained 42% of the total variation in the biological data set. The correlation between the first canonical variables TOXI and BIOL (canonical correlation) was 0.94 (P < 0.0001). Therefore, it is reliable and feasible to use the achievement to assess toxicity of heavy metal combined polluted soil using canonical analysis. Toxicity of soil combined polluted by heavy metals to plant community was estimated by comparing the IC50 values describing the concentration needed to cause 50% decrease with grow rate compared to no metal addition. Environmental quality standard for soils prescribe that all these tested concentration of heavy metals in soil should not cause hazard and pollution ultimately, whereas it indicated that the soils in second grade cause more or less than 50% inhibition rates of wheat growth. So environmental quality standard for soils can be modified to include other features.

Greenhouse gas emissions from a constructed wetland for municipal sewage treatment.

The fluxes of greenhouse gases (methane and nitrous oxide) emission from a constructed wetland in the Eastern China as municipal sewage treatment were measured from June 1999 to August 2000 by the closed chamber method. The constructed wetland for municipal sewage treatment is a significant source of methane, up to 976.6 x 10(6) g CH4/a, which was emitted from the constructed wetland with the area of 495,000 m2 and wastewater loading rate of 12,000 m3/d. Its daily mean methane flux reached 5.22 g CH4/(m2.d), 250 times as much as that in natural wetland in the same latitude region. 227.8 mg CH4 was produced from the treatment of 1 liter wastewater, up to 700-1000 times as much as that in the secondary treatment. The emission of nitrous oxide from the constructed wetland is not higher than that from secondary treatment of wastewater, only 0.07 mg N2O/L.

[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.

[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.

[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.

[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).

[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.

[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.