[Distribution characteristics and model establishment of microorganisms in electrokinetic remediation of organic contaminated soil.] / 有机污染土壤电动修复过程中微生物的分布特征及模型构建.

Soil microorganisms would reproduce rapidly and migrate directionally under the applied electric field. In this study, tetradecane-degrading bacteria were added at different locations in soil, and 1 V·cm-1 unidirectional DC electric field was applied to investigate the migration, distribution, and degradation characteristics of target bacteria in soil. The results showed that microorga-nisms migrated to the cathode and anode by electrodialysis and electrophoresis, respectively. The number of microorganisms migrated by electrodialysis was 3.5 times of that by electrophoresis. The application of electric field could make the soil environment spatially heterogeneous to affect the growth of microorganisms. The average number of soil microorganisms under electric field was 1.16×108 CFU·g-1(6 days), which was 2.3 times of that without electric field. S2 to S4 were the efficient growth areas of microorganisms, with the average number after 30-day electric treatment being 2.8-3.5 times of that on the anode and cathode, and 2.1 times of that in the control. There was a significant positive correlation between the tetradecane degradation rate and the number of microorganisms (r=0.895, P＜0.05). The optimal tetradecane degradation region was near the cathode (S4), where its degradation rate reached 94.6%. Based on these results, a model modified by environmental factors was established to simulate the spatial distribution of microorganisms under the combined effect of electrokinetic stimulation and transportation. According to the model, the number distribution of microorganisms could be deduced when exogenous bacteria were added in a fixed section. The results provide a theoretical basis for the efficient import of exogenous functional bacteria in electrokinetic-bioremediation of organic contaminated soil.

[Pollution assessment in the intertidal zone of Beibu Gulf using multi-biomarker pollution index].

This paper assessed the coastal environmental quality along the Beibu Gulf using a statistical approach, multi-biomarker pollution index (MPI). Samples of clam (Paphia undulata) and sediment were collected at nine sites from the intertidal zone of Beibu Gulf in April 2011. Nine biomarkers of response were measured both in gill and digestive gland in Paphia undulata, and twelve kinds of contaminants were measured in different sediment samples. According to the Pearson' s correlation coefficients between biomarker responses in Paphia undulata and contaminant levels in sediments, five biomarkers either in gill for oxidized glutathione (GSSG), reduced glutathione (GSH), glutathione S-transferase (GST) or in digestive gland for thiobarbituric acid reactive substances (TBARS) and glutathione peroxidase (GPx) were selected for MPI calculation. For each biomarker at each site, a response index was allocated, and the MPI value of this site was calculated as the sum of the response index of the five biomarkers. The results of the calculation (MPI values from 18 to 39) showed significant differences among sampling sites. The environmental quality of all sites ranged from class 1 (clean) to class 3 (lightly contaminated), and no site fell into class 4 (contaminated) or class 5 (heavily contaminated), indicating a good environmental quality in the intertidal zone of Beibu Gulf. However, the environmental quality at some sites (S1, S3, 54 and S7) fell into class 3 (lightly contaminated), indicating mild interference from human activities has occurred.

[Marine environmental assessment approaches based on biomarker index: a review].

Biomarkers are applied worldwide in marine environmental assessment due to their "early warning" function to chemical pollutants. Several integrative index approaches such as multi-marker pollution index (MPI), integrated biomarker response (IBR), bioeffect assessment index (BAI), biomarker response index (BRI), and health assessment index (HIS), have been developed based on biomarkers. By transforming the complex alterations of biomarkers into a single class or value, these approaches have been so far the useful tools for assessing the environmental quality. This review summarized the establishment of evaluation indicator system, the calculation of integrative index, the grading of pollution status, and the practical applications of each approach, and discussed the existing problems in marine environmental assessment based on biomarker index. Some improving suggestions were also proposed.

[Study on the quantitative change of anthraquinonoids of Rhei in the preparation of dachengqi].

OBJECTIVE: To study the scientific evidence of the traditional preparation of Dachengqi: "Boiling Aurantii Immaturus and Magnoliae Officinalis first, and then adding Rhei to decoct together. Discarding the dregs, adding Natrii Sulfas into the decoction and drinking the upper solution when the Natrii Sulfas has dissolved completely". METHOD: The concentrations of free and combined anthraquinonoids(emodin, rhein, chrysophanol, physcion) in different decoctions were determined with HPLC method respectively. RESULT: When Natrii Sulfas, Aurantii Immaturus and Magnolias Officinalis are decocted with Rhei in different schemes, the concentrations of anthraquinonoids were changed regularly. CONCLUSION: The scientific evidence of traditional preparation method greatly increased the concentrations of the active components in Dachengqi.