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| Study on the migration and release of lead and chromium and in the vadose zone |
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Abstract Sand-column simulations were designed to investigate charateristics of migration and transformation of Pb2+ and Cr6+ and their releasing mechanism flushed by rain water in the vadose zone. Experimental results indicated that the migration rate of hexavalent chromium was ten times more than that of lead in the vadose zone; and the migration rate of lead and hexavalent chromium was 7.25cm/d and 0.4cm/d in the coarse sand and 4.46cm/d and 0.36cm/d in the fine sand, respectively. Reduction reaction of hexavalent chromium was not a dominant process in the vadose zone; the trivalent chromium was not detected in the water, and the content was 0.006mg/kg in the vadose media. The removal efficiency of Pb2+ was 0.056% and 0.112%, and Cr2O72- was 62.33% and 40.36% for fine sand and coarse sand columns flushed by rain water, respectively. Therefore, the mobility of Cr2O72- was high in the vadose zone and prone to removing from vadose media by rain flushing, Pb2+ showed a reverse trend compared with Cr2O72-.
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Received: 11 November 2013
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CHEN Huan-Yu, LIU Jing-Qing, WEI Zong-Yuan, ZHANG Hui-Hui, HE Xiao-Fang, ZHOU Xiao-Yan, QIU Shang-De, HU Bao-Lan, LOU Li-Ping. Radial differences in contaminant distribution in large-diameter pipe scales of main pipelines in drinking water distribution system[J]. CHINA ENVIRONMENTAL SCIENCECE, 2015, 35(9): 2706-2712. |
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