Advanced Materials Research Vol. 414

Abstract: Compared to the other countries in the world, the research and practice on management of Chinese contaminated sites has just begun, yet it faces a number of problems. This paper analyze the manage problems of Chinese contaminated sites from the following aspects: the relevant laws and regulations of contaminated sites, standards, remediation technology, fund-raising and so on. Furthermore, it put forward that achieving legalization, institutionalization and industrialization of the remediation work is the key to solve the manage problem of the Chinese contaminated sites.

Abstract: The manganese contents of soils and dominant plants from the manganese mining areas in Xiushan autonomous county of Chongqing were researched in this paper. The results showed that the Mn pollution of soil in the Mn mining tailings were very serious with high indexes (I_geo>5), and sewage irrigated soil was also contaminated by manganese metal. The uptake of Mn by dominant plants can be classified into three types according to the Mn contents in plant shoots and roots, (1) the accumulator which absorbs a large content of Mn by the roots and transports it to the shoots, (2) the root compartment which also absorbs a large content of Mn but mainly in the roots, and (3) the excluder which absorbs a smaller content of Mn than the accumulator. The edible parts of radishes and peppers growing in the Mn mining tailings and cropland were all seriously polluted by manganese and not safe for human health.

Abstract: Heavy metal accumulation in Xihe River sediments was studied, and also its potential environmental risk was evaluated using geoaccumulation index (I_geo). The results showed that mean concentrations of Hg, Cd, Zn, Pb, Ba, Bi, Sn and Sb were 2.73, 18.42, 1066.1, 128.8, 366.9, 7.76, 24.70 and 8.53 mg/kg, respectively. The values of examined heavy metals, except for Ba, were higher than the reference of deep soil. There were different accumulation characteristics for heavy metals at different river sections. Cadmium and Pb concentrations in sediment dropped from upper to lower reaches along river, but Ba was quite the reverse. The potential environmental risk of heavy metals in sediments was in order: Cd > Hg > Bi > Zn > Sb > Sn > Pb > Ba. The river was subjected to a higher potential risk by Hg, Cd, Zn and Bi, a medium-high risk by Sn and Sb, and a lower risk by Pb and Ba.

Abstract: Currently, the World confronts with several major problems, including environment pollution and energy shortage. To utilize metal-contaminated soils safely and to solve the problem of shortage of farmland for bioenergy development, we have postulated a new strategy of cultivating energy plants in Cd-contaminated soils for bioenergy production, and this can also be combined with phytoremediation. Here, we focus on the advantage and feasibility of this approach by a review of recent developments in basic and applied research relevant. It is concluded that cultivation of energy plants in metal-contaminated land for bioenergy production is a high beneficial, environment-friendly technique that is also technically feasible. It might not only cover the shortages of phytoremediation and bioenergy production, but also makes the metal-contaminated land fully utilized and productive, and this is benefited for both agriculture and farmers.

Abstract: The potential ecological risk index,proposed by Hakanson, was employed for evaluating the heavy metal contamination of the Yangtze River sediment in Chongqing downtown section. Basing on the analysis of last fifteen years monitored data from two national monitoring sections, the results indicated that: The potential ecological risk of the Yangtze River Chongqing downtown section was classified as moderate. The sequence of potential ecological risk was Zn< Pb (As) < As (Pb) < Cu < Cd< Hg, while the concentration of heavy metal in the sediment was Zn> Cu >Pb> As > Cd > Hg. The concentrations of Cd and Cu had significant correlation, Hg should be taken into prior consideration for pollution control and reduction due to its highest potential ecological risk. The RI in 2005 was highest, Hg contributed the most. All the heavy metal except for Pb had distinctive variance, but the variance of RI was not significant annually, It might carried the connotation of little difference on Pb emission amount. According to the location of monitoring site factor variance analysis, it implied that only the potential ecological risk of As and Cd varied significantly.

Abstract: In order to describe petroleum hydrocarbon contaminants (PHCs) transport feature in saturated zone, two-dimensional sandbox was designed to carry out physical simulation experiment, and infiltration, migration and distribution of PHCs in saturated zone were investigated. Meanwhile, MOFAT simulator was selected to carry out numerical simulation research, and simulator accuracy was analyzed by comparing to physical simulation data. Results indicated that MOFAT simulator could simulate and predict PHCs transport behavior in saturated zone.

Abstract: To develope a practicable stabilization method for remediation chromium contaminated soil, reductant and chelate reagent were investigated for stabilization artificical chromium contaminated soil, and the stabilization effect was tested through extraction toxicity assay after stablized soil was oxidized at pH 12. The experimental results showed that the composition of sodium bisulfite & ammonium pyrrolidine dithiocarbamate was an ideal stabilizer of chromium in soil, and the extraction toxicity was much less than that of classical stabilized chromium polluted soil with only reductant or the maximum critical value in GB16889-2008, which suggested that the composition of reductant & compound of dithiocarbamate might be practically appllied for remediation chromium contaminated soil because it was likely to remain chromium much more stable in soil for a long time and significantly decrease Cr mobility.

Abstract: Soils contaminated with diesel oil were remediated with alfalfa (Medicago sativa) by outdoor pot experiment over a 5-growth season treatment, with pollutant levels, special microbial inoculators, fungi inoculators, and organic manure as control factors. The dynamics of residual concentrations of mineral oil and PAHs in soil of different phytoremediation treatments during the 5 seasons were determined. Results showed that significant reduction of contaminant concentration was achieved. At the end of the fifth growth season, initial concentrations of mineral oil were reduced by 96.5% to 98.8% in the phytoremediat treatments. Among the four factors, bacterial and fungi inoculators showed no significant effect on the contaminant removal in the process of long-term bioremediation. Effect of organic fertilizer amendments differed depending on the diesel concentration. In the highly contaminated treatments (15000 and 30000 mg/kg dry weight) remarkable stimulation was detected with the increase of fertilizer amendment; however, the trend was just reversed in the lightly contaminated treatments (5000 mg/kg dry weight) with the increase of manure amendment.

Abstract: With the rapid development of urbanization and industrialization in Chongqing, effect of heavy metals on brownfield has been paid more and more attention. 8 brownfields in steel industry, 15 brownfields in chemical industry, 18 brownfields in machining industry and 7 brownfields in pharmaceutical industry were selected as research objects, and eight heavy metals including mercury (Hg), lead (Pb), arsenic (Ar), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn) in soil were analyzed. Single factor pollution index (SFPI) and integral pollution index (IPI) was used to assess the pollution degree of these sites. The comprehensive results showed that the brownfields in the 4 studied industries had been affected by the heavy metals which produced in industrial activities. Machining industry had the greatest impact on the brownfield in Chongqing, also, the effect of chemical industry and steel industry to the soil were tremendous. Only pharmaceutical industry had little influence on the soil environment.

Abstract: Cement kiln co-processing technology is one of powerful method for disposal soild hazardous waste internationally owing to advantages of economic and environmental friend. However, It seems to be abused in brownfield remediation in Chongqing recently, for instance, it is ubiquitously recommeded or pratically applied for disposal chromium conteminated soil. To help local environmental protection departments clarify the advantages and limitations of cement kiln for Cr-contaminated soil treatment, this paper focuses on advantages and the negative effects of co-polluters in Cr-contaminated soil.