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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 [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 β-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. [ABSTRACT FROM AUTHOR]

Abstract: 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[sup 6] g CH[sub 4]/a, which was emitted from the constructed wetland with the area of 495000 m² and wastewater loading rate of 12000 m³/d. Its daily mean methane flux reached 5.22 g CH[sub 4]/(m² ⋅ d), 250 times as much as that in natural wetland in the same latitude region. 227.8 mg CH[sub 4] 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 mgN[sub 2]O/L. [ABSTRACT FROM AUTHOR]

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 (EC_{50}) 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. [ABSTRACT FROM AUTHOR]