Advanced Materials Research Vol. 414

Abstract: This paper conclude and determine the range of key parameters based on the effects of heavy metal Pb to Human blood-Pb health risk. According to China's reality, Pb levels in air, drinking water are 0.122~1.0 ug/m and 2~10ug/L; ingestion of Pb from food by children of 0~6 years old is 10~25ug/d. Pb cut-off value for residential land soil are calculated with the Integration Exposure Uptake Biokinetic Model (IEUBK). The result shows the Pb cut-off value for residual land is 294.5mg/kg. The result provides a reference for cut-off value of Content of lead in soil, and brings convenience for the research and practice of remediation Pb contamination in soil.

Abstract: This paper discusses the migration of the total petroleum hydrocarbon (TPH) contamination, which concludes the migration rule of the TPH contamination through designing indoor soil column leaching experiments. Through researching the migration concentration of TPH in different leaching amount, results shows that the ability of migration of TPH is more powerful when there is more leaching amount. But overall, the affection caused by different leaching amount is not obvious. The results of this research can provide guidance to the nonproliferation and remediation of petroleum contamination.

Abstract: Panji is rich in coal reserves. The rapid development of social economy and increasing mining scales cause the subsided land, bulk deposition of solid waste, soil, water and air pollution, crop yield reduction or crop failure and ecological deterioration, which endanger the living and development of people in the mining area. Based on the current situation of subsidence area and evaluation of land reclamation potentiality, this paper puts forward the establishment of land ecological economic pattern and the application to ecological project to improve land condition, cultivate land resource potentiality and restore the service function and species diversity of ecological system in the subsidence area of Panji Coal Mine in order to provide reference for ecological, economic and social sustainable development in Panji.

Abstract: In order to study heavy metals’ pollution characteristics in soil of a small arms shooting range, soil samples at surfaces and different depths were collected from a shooting range located in suburb of Beijing and analyzed for heavy metals (Pb、Cd、Cu、Zn、P、As、Hg and Sb). Site investigation results showed that the soil in the shooting range was seriously polluted by Pb bullets, and there are positive correlations between total concentrations of Hg, Cu, Pb, Zn, Sb and Pb in soil particles less than 2mm, indicating soil heavy metals’ combined pollution characteristics.

Abstract: This study focused on the technical measures of revegetation on ferrum tailings bank in Huludao, China. Adopting field test method, a revegetation trial was conducted on the Yangjiazhangzi waste ferrum tailings bank. By composting the urban sludge + river mud + straw inside planting pit to ameliorate tailings matrix, planting perennial herb to establish closed type sand barrier to shelter bush-herbage growth, transplanting nutrition cup bush seedlings and sowing herbage seed on the composting pit to establish bush-herbage clump, these technical measures can solve the major constraints to plant growth and establish survival bush-herbage vegetation at lowcost. The results show that Pit layered composting is the cost-effective measure to improve ferrum tailings planting matrix; Planting perennial herb sand barrier t is a good measure to improve microhabitat; Planting bush-herbage clump is a good pattern to resist the extreme ferrum tailing environment; Hippophae rhamnoides Linn., Caragana Korshinskii Kom., Medicago sativa Linn.and Astragalus adsurgens Pall are good pioneer species for revegetation on the ferrum tailings bank. Experiment proved that the combination of these technical measures can reconstruct vegetation, this revegetation pattern is worthy of reference for similar mine ecological restoration.

Abstract: Electrokinetic remediation, variably named as electrochemical soil processing, electromigration, ectrokinetic decontamination or electroreclamation, uses electric currents to extract radionuclides, heavy metals, certain organic compounds, or mixed inorganic species and some organic wastes from soils and slurries. This paper presents the experimental study on the effect of applied voltage on the electrokinetic removal of the chromium from kaolin at laboratory scale. Potassium dichromate was chosen as the pollutant and its initial concentration was 100 mg·kg^-1 and 500mg·kg^-1, the moisture content of samples is 50%. The experiments were operated 48 hours and the pH of cathode was control at 4-7 with of acetic acid. And a series of voltages were applied. The results indicate the removal efficiencies increase with the increase of applies voltage, when the voltage is 1V/cm, the efficiencies increase significantly, the efficiency reach up to 76.7% and 89.8% of two studied samples. The electric energy consumptions also increase significantly due to the increase of applied voltage. The experiment data show 1-1.5V/cm is cost effective voltage range for the soils studied.

Abstract: The effects of desorption temperature, air flow rate and initial soil moisture on the desorption efficiency of nitrobenzene from contaminated soil were investigated. Experiments were conducted with Yellow-brown soil contaminated by nitrobenzene in a vertical heating oven. Results showed that there was a trend that desorption efficiency of nitrobenzene increased with the increase of desorption temperature. At 250 °C, when desorption time was 30 min, desorption efficiency reached 99.8%, and the residual concentration of nitrobenzene in treated soil was only 0.3 mg/kg, which was far less than the A-level limit of Standard of Soil Quality Assessment for Exhibition Sites of China (HJ 350-2007). Besides, both too high and too low air flow rates were not in favor of nitrobenzene desorption. When the air flow rate was 2.6 m³/h, a maximal desorption efficiency reached during the early thermal desorption. In addition, initial soil moisture had a significant influence on desorption efficiency during the early thermal desorption. Nevertheless, with increasing desorption time, the effect of soil moisture diminished gradually and when desorption time reached 30 min, the effect nearly disappeared. The results obtained from this work could provide some scientific foundations for the practical soil remediation for nitrobenzene-contaminated sites by thermal desorption technology.

Abstract: In this paper, the two-dimensional saturated soil adsorption and desorption of contaminant transport model was considered, and it is discreted by the Crank-Nicolson difference scheme method. The benzene contaminant in the original organic chemical cesspool was determined, and the transportation of benzene contaminant is simulated by Matlab software. Simulation results show that the benzene concentration in the sewage pool reduced to 1.15mg/kg, where can be used for various soil types by the migration effect of the soil after a decade. This established model and simulation methods can be used for estimating other existing benzene contaminated soil pollution.

Abstract: Sampling the doubtful contaminated soil and rocks by the way of grid layout along the Yangtze River and Jialing River, near some hospitals and factories in the urban area of Chongqing, and measuring the samples specific activity of radionuclide ²²⁶Ra, ²³²Th, and ⁴⁰K. Analyze the radioactive levels of doubtful contaminated sites by the measurement results, to make recommendations for monitoring environmental radioactive levels and propose remediation steps of contaminated soils.

Abstract: The distributions in different particle sizes of municipal solid waste incinerator (MSWI) fly ash in spring and autumn were studied by sieve method, and the heavy metal contents of Cu, Zn, Mn, Pb, Cd, Ni, Cr and Hg in different size particles were measured, and the heavy metal leaching amount in the different particle size were also studied under the GB5085.3-2007 and USEPA-TCLP leaching procedure, respectively. The results showed that the particle size of fly ash in autumn was relatively smaller than that of in spring, more than 90% of particle size of fly ash in spring and autumn were less than 250 μm, and the particle size in 83-105 μm of fly ash in spring distributes in most with about 40% of the total, but 105-149 μm in autumn distributes in most, accounted for about 45% of the total. The content of heavy metals decreased first and then increased with the decreasing particle sizes except for Ni, and the content of heavy metals in the spring is higher than that of in autumn except for Fe and Zn. Under the GB5085.3-2007 leaching procedure, the leaching content of Cu, Zn and Ni in MSWI fly ash in both spring and autumn and Cr in spring were not beyond limited standard, but Pb and Cd in both spring and autumn and Cr in autumn were beyond limited standard. However, under TCLP leaching procedure, the leaching content of Pb, Cr and Cd in both spring and autumn were beyond the standard limits.