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Several main metabolites of benzo[a]pyrene (BaP) formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone (BP 1,6-quinone), trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (BP 7,8-diol), 3-hydroxybenzo[a]pyrene (3-OHBP), were identified by high-performance liquid chromatography (HPLC). The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that (1) the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; (2) the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; (3) the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% (w/v), concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.

Biomarkers in higher plants played an important role to estimate exposure effects of pollutants in soil ecosystem and have received increasing attention in recent years. The qualitative and quantitative modifications arising in amplified fragment length polymorphism (AFLP) profiles as a measure of DNA effects were compared with a number of parameters, namely, the root length, total soluble protein content in root tips, chlorophylls content and shoot size to select the most sensitive biomarker responding to copper stress in the range of 0-600 mg/kg. The changes occurring in AFLP profiles of root tips following Cu treatment included loss of normal bands and appearance of new bands and variation in band intensity in comparison to that of the normal seedlings. A reduction in root length was observed at the 200 mg/kg of copper, which was accompanied with a decrease in total soluble protein content. According to their sensitivity to the copper toxicity, the above indicator rank in the following order: AFLP profiles > total soluble protein content > root length > chlorophylls content > shoot. We concluded that the AFLP offered a useful alternative biomarker assay for the detection of genotoxic effects of environmental pollutants.

Two indigenous microorganisms, Bacillus sp. SB02 and Mucor sp. SF06, capable of degrading polycyclic aromatic hydrocarbons (PAHs) were co-immobilized on vermiculite by physical adsorption and used to degrade benzo[a] pyrene (BaP). The characteristics of BaP degradation by both free and co-immobilized microorganism were then investigated and compared. The removal rate using the immobilized bacterial-fungal mixed consortium was higher than that of the freely mobile mixed consortium. 95.3% of BaP was degraded using the co-immobilized system within 42 d, which was remarkably higher than the removal rate of that by the free strains. The optimal amount of inoculated co-immobilized system for BaP degradation was 2%. The immobilized bacterial-fungal mixed consortium also showed better water stability than the free strains. Kinetics of BaP biodegradation by co-immobilized SF06 and SB02 were also studied. The results demonstrated that BaP degradation could be well described by a zero-order reaction rate equation when the initial BaP concentration was in the range of 10-200 mg/kg. The scanning electronic microscope (SEM) analysis showed that the co-immobilized microstructure was suitable for the growth of SF06 and SB02. The mass transmission process of co-immobilized system in soil is discussed. The results demonstrate the potential for employing the bacterial-fungal mixed consortium, co-immobilized on vermiculite, for in situ bioremediation of BaP.

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.

The rates of photodegradation and photocatalysis of benzo[a]pyrene (BaP) on soil surfaces under UV light have been studied. Different parameters such as temperature, soil particle sizes, and soil depth responsible for photodegradation, catalyst loads and wavelength of UV irradiation blamed for photocatalysis have been monitored. The results obtained indicated that BaP photodegradation follows pseudo-first-order kinetics. BaP photodegradation was the fastest at 30 degrees C . The rates of BaP photodegradation at different soil particle size followed the order: less than 1 mm>less than 0.45 mm>less than 0.25 mm. When the soil depth increased from 1 mm to 4 mm, the half-life increased from 13.23 d to 17.73 d. The additions of TiO2 or Fe2O3 accelerated the photodegradation of BaP, and the photocatalysis of BaP follows pseudo-first-order kinetics. Changes in catalyst loads of TiO2 (0.5%, 1%, 2%, and 3% (wt)) or Fe2O3 (2%, 5%, 7%, and 10% (wt)) did not significantly affect the degradation rates. Both BaP photocatalysis in the presence of TiO2 and Fe2O3 were the fastest at 254 nm UV irradiation.

The phytotoxicity of chlorobenzoic acids (CBAs) was studied and the biochemical endpoints' suitability and sensibility was evaluated. Two terrestrial plant species in the same family were exposed to different concentrations of CBAS and tested their germination according to the guideline of Organization for Economic Cooperation and Development (OECP, 1984). The results showed that CBA dose-inhibition rate of classical endpoint had the distinct linear relationship in the range of 10%-50% inhibition rate for root elongation (p < 0.01), and the dose variances of CBAs had the greater influence on the inhibition rate of germination than on inhibition rate of root elongation. The CBA dose half effect concentration-inhibition rate of two antioxidant enzyme activity superoxide dismutase (SOD) and catalase (CAT) had the quadratic relationship, and CBA dose-inhibition rate of the peroxides (POD) activity had the linear relationship (p < 0.05). Comparing the half effect concentration (EC50) of two kinds of endpoints, the POD activity was more sensitive than classical endpoint, however, SOD and CAT activity were not sensitive in the experiment.

To exploit peashrub resources in Ordos as fodders, it is very crucial to realize industrial production of cheap cellulase of high activity by optimizing culture technology, especially culture substrate. In this study, a new prescription experiment based on uniform design ideal was invented and successfully applied in the solid fermentation of Trichoderma koningii F244, which was performed with two different temperature degrees. The activities of FPA, cotton lyase, CMCase and beta-glucosidase were assayed and then mathematical models of enzymatic activities, which were figured out by Unconstraint Mathematical Programming, were developed by Multivariate Regression Program of SPSS10.0. Enzymatic activities of optimized substrate prescriptions corresponding to mathematical models were forecasted to determine an ideal substrate prescription. It is revealed that in solid fermentation, Tween80 has negative effect on cellulase production. Furthermore, the ideal prescription for cellulase complex production by Trichoderma koningii F244 was straw powder 16.9%, wheat bran 26.5%, (NH4)2SO4 9.5% and water 47.1%, whose corresponding cellulase activity was expected to be at the same high level with that of Trichoderma reesei Q9414 on its own recommended substrate. Especially, goats mainly fed on peashrub tissues mixed with cellulase complex of this prescription and culture technology, got an incremental ratio of 0.3 kg/d, which brought a very promising feeding prospect for local peashrub resource. By populization of this cellulase complex, it can integrate living standard, economic construction of local residents into vegetational restoration tightly and thus this paper will be very meaningful to be use for reference for western China like Ordos to realize its sustainable development of economy, society and environment.

Effects of bioremediation on microbial communities in soils contaminated with petroleum hydrocarbons are a scientific problem to be solved. Changes in dominate microbial species and the total amount of microorganisms including bacteria and fungi in rhizospheric soils after bioremediation were thus evaluated using field bioremediation experiments. The results showed that there were changed dominant microorganisms including 11 bacterial strains which are mostly Gram positive bacteria and 6 fungal species which were identified. The total amount of microorganisms including bacteria and fungi increased after bioremediation of microbial agents combined with planting maize. On the contrary, fungi in rhizospheric soils were inhibited by adding microbial agents combined with planting soybean.

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.

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.