Effect of Low-Molecular Organic Acids on the Migration Characteristics of Nickel in Reclaimed Soil from The Panyi Mine Area in China.

This study investigated the effects of low molecular weight organic acids (citric acid and malic acid) on the migration properties of nickel in soil. A reclaimed soil sample was obtained from the Panyi Mine in Huainan City, China. The effects of adding different concentrations of Ni, citric acid (CA) and malic acid (MA) were assessed on the migration and transformation of soil Ni forms. The results showed: (1) An increase in soil Ni activity with increasing Ni concentrations. (2) An increased proportion of exchangeable forms of Ni in soil with increased malic acid and citric acid concentrations, effectively promoting Ni mobility. In addition, the active Ni fraction in reclaimed soil increased significantly with increasing concentrations of citric and malic acid. The nickel activation effect of citric acid was found to be higher than that of malic acid. (3) The activation effect of organic acids on Ni weakened with aging, exhibiting a gradual transformation from the loosely bound form of Ni, to the strongly bound form. The results of this study provide a theoretical basis for improving the effectiveness and efficiency of the phytoremediation techniques used for the treatment of Ni-polluted soils.

Ecological Risk Assessment and Influencing Factors of Heavy-Metal Leaching From Coal-Based Solid Waste Fly Ash.

In order to promote and broaden the utilization of fly ash as a resource, the fly ash from a 2,660-MW coal-fired power plant in Huainan (China) was investigated. The physical and chemical properties of fly ash were characterized by scanning electron microscopy, energy spectrum analysis, and XRD. The content and different forms of the heavy metals Cd, Cr, Cu, Co, and Ni were determined by acid digestion, oscillation leaching, and Tessier five-step extraction. The effect of pH, temperature, and particle size on the leached amount of heavy metals was studied. Finally, the ecological risk index was calculated for each heavy metal via the risk assessment coding (RAC) method and Hakanson ecological risk assessment method, allowing the ecological risk of fly ash to be determined under different environmental conditions. Results showed that the average concentrations of Cd, Cr, Co, and Ni were all below the risk screening values reported for environmental pollutants (pH > 7.5). Under varying pH, temperature, and particle size conditions, the leached amounts (oscillation leaching) were below the soil risk screening values for agricultural land in China. An RAC-Cd value of >50% indicates a high ecological risk, while the RAC values of Co and Ni were between 10 and 30%, indicating a medium ecological risk, and the RAC values of Cr and Cu were <10%, indicating a low ecological risk. With increasing pH, the potential ecological risk index (RI) decreased, with a maximum RI of 59.62 observed at pH 2.8. With increasing temperature, the potential ecological RI increased initially to a maximum of 27.69 at 25°C and then decreased thereafter. With increasing particle size, the ecological RI decreased, with the highest RI of 4.06 occurring at <0.075 mm. The Hakanson ecological RI value was below 150, indicating a slight ecological risk. Therefore, fly ash can be considered as a soil additive and conditioner that is suitable for use in the improvement of reclamation soil in coal mining subsidence areas.

Effect of Low-Molecular-Weight Organic Acids on Migration Characteristics of Pb in Reclaimed Soil.

The effect of low-molecular-weight organic acids (citric acid and malic acid) on the migration characteristics of Pb in contaminated soils was explored in this study. Reclaimed soil was collected from the coal gangue hill area of the Panyi mine in Huainan City (China). The effect of citric acid and malic acid on the form of Pb present in the reclaimed soil was analyzed by spiking soil samples and simulating Pb-contaminated soil. The results indicate the following. 1) With increased concentration of exogenous Pb, the activity of Pb in the reclaimed soil was effectively improved. 2) The addition of citric acid and malic acid both resulted in an increased fraction of exchangeable Pb in the soil, which effectively promoted the active Pb fraction. As the concentrations of citric acid and malic acid increased, the active Pb fraction of the reclaimed soil increased accordingly. The Pb activation effect of citric acid was observed to be greater than that of malic acid. 3) With extended soil aging time, the activation effect of organic acids on Pb weakened, with the loosely bound Pb gradually transforming into strongly bound Pb. Chelating agents can activate heavy metals in soil, mainly through the combination of chelating agents and heavy metal ions in the soil solution to form soluble metal chelates, so as to increase the bioavailability of heavy metals in soil to plant roots. Therefore, adding citric acid can be considered as a strategy to enhance the efficiency of reclaimed soil remediation because of the ability of Pb activation.

[Program optimization in the stage treatment of periarthritis of shoulder with acupuncture, moxibustion and positive functional exercise].

OBJECTIVE: To optimize the therapeutic programs for periarthritis of shoulder treated with acupuncture, moxibustion and kinetohterapy with orthogonal design method adopted. METHODS: The orthogonal design table of L8 (2(7)) hierarchical principle was used to randomly divide 192 patients of periarthritis of shoulder into 8 groups, 24 cases in each one. Separately, 4 factors and each different 2 levels were adopted in treatment, named acupuncture timing (factor A: A, acute stage, A2 adhesion stage), acupoint combination (factor B: B, local acupoints, B2 local acupoints and distal acupoints along meridians), filiform needling and warm needling therapy (factor C: C1 acupuncture with filiform needle, CZ acupuncture with filiform needle and warm needling therapy) and positive functional exercise (factor D: D1 without positive functional exercise, D2 with positive functional exercise). The treatment was given once a day, 10 treatments made one session and 2 sessions were required totally. The time points of observation were the point after 1 session of treatment and after 2 sessions of treatment. The short-form McGill pain questionnaire (MPQ) and shoulder joint motor disturbance score were adopted for evaluation. RESULTS: In the orthogonal design analysis, taking the hierarchical factors into consideration, the age was considered as the main factor in the evaluation of shoulder pain and shoulder motor disturbance (P<0.01), and the shoulder function grade apparently impacted pain evaluation and the efficacy on shoulder motor disturbance (P<0.01). The best combination of 4 factors and 2 levels were A1B1CzD2 and A2BC2D2. SAS statistical analysis showed that at acute stage and adhesion stage, CZ Dz , meaning acupuncture with fifiform needling and warm needling therapy combined with positive functional exercise, is the main factor of the improvements of shoulder motor function (P<0.05). CONCLUSION: For periarthritis of shoulder at acute stage, the combined therapy of acupuncture at local acupoints, warm needling and positive functional exercise is adopted. At chronic stage, the combined therapy of acupuncture at local acupoints and distal acupoints, acupuncture with filiform needle and warm needling and positive functional exercise is the best program. Additionally, in clinical treatment, the patients' age, sex, shoulder joint function and duration of treatment should be considered comprehensively for the impacts on the efficacy.