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小白河生态修复区沉积物中砷的空间分布特征
张慧娟,刘云根,侯 磊,等
作者单位
张慧娟 西南林业大学 环境科学与工程学院 
刘云根 西南林业大学 环境科学与工程学院农村污水处理研究所 
侯 磊,等 西南林业大学 环境科学与工程学院农村污水处理研究所 
摘要:
【目的】研究生态修复区重金属砷的分布特征及其潜在生态风险,为重金属污染河流治理工程的建设提供理论依据。【方法】以云南省文山州内跨境河流小白河生态修复区为研究对象,沿水流方向设置A、B、C、D、E 5个断面,其中A断面位于生态修复区上游,为背景断面; E断面位于生态修复区下游,为削减断面; B、C、D断面位于生态修复区内,均为控制断面,采集5个断面的沉积物样品,分析了小白河生态修复区表层(0~10 cm)、中层(10~20 cm)和底层(20~30 cm)沉积物总砷含量的空间分布规律,并运用Hakanson方法对沉积物中砷的潜在生态风险进行评价。【结果】云南小白河流域沿水流方向5个断面河心位置表层沉积物中的总砷含量呈先增加后减少趋势,生态修复区砷沉积效果明显,修复区下游断面河心位置表层沉积物中的总砷含量((1.29±0.001) g/kg)相对上游断面((1.39±0.001) g/kg)降低7.19%。水平方向上,在相同水力停留时间下,生态修复区内沿水流方向上3个控制断面表层(0~10 cm)沉积物中总砷含量平均值表现为D断面((4.05±2.02) g/kg)>B断面((3.49±3.36) g/kg)>C断面((2.15±1.92) g/kg)。垂直方向上,生态修复区3个断面沉积物中总砷含量平均值表现为表层>中层>底层,呈现出明显的表层富集特征。潜在生态风险评价结果表明,生态修复区3个断面沉积物中砷污染处于“高”及其以上等级的生态风险。【结论】小白河重金属砷污染风险较高,在进行治理时应对生态修复区沉积物进行清淤,并进行污染源控制。
关键词:    生态修复区  沉积物  空间分布  生态风险
DOI:
分类号:
基金项目:国家自然科学基金项目(51469030);云南省应用基础面上项目(2009ZC083M);云南省高校优势特色重点学科(生态学)建设项目
Spatial distribution of arsenic in sediment of the Xiaobai River ecological restoration area
ZHANG Huijuan,LIU Yungen,HOU Lei,et al
Abstract:
【Objective】The distribution characteristics of arsenic and potential ecological risk grades in the Xiaobai River ecological remediation area were studied to provide basis for heavy metal pollution management.【Method】Five cross sections of A,B,C,D and E were set up along the flow direction of the Xiaobai River in ecological remediation area in Wenshan,Yunnan.The A and E sections at upstream and downstream of ecological remediation area were background and reduction section,respectively.Other three were control sections.Sediment samples were collected and the spatial distribution characteristics of arsenic in surface (0-10 cm),middle (10-20 cm) and bottom (20-30 cm) layers were analyzed.Hakanson method was also used to evaluate the ecological risk of sediment arsenic.【Result】Accumulation of arsenic was observed in the ecological restoration site.Compared with the upstream section ((1.39±0.001) g/kg),arsenic concentration in the downstream section ((1.29±0.001) g/kg) was decreased by 7.19%.In the horizontal direction,the average contents of total arsenic in sediments from the three sections along the flow direction were in the order of D((4.05±2.02) g/kg)>B((3.49±3.36) g/kg)>C((2.15±1.92) g/kg).In the vertical direction,the total arsenic contents were in the order of surface layer>middle layer> bottom layer,showing clear surface enrichment.Potential ecological risk assessment showed that the arsenic pollution at the three sections in the ecological remediation area was at high level or above.【Conclusion】The risk of arsenic pollution in the Xiaobai River ecological remediation area was very high,and it was suggested to dredge sediments and control sources for pollution control.
Key words:  arsenic  ecological restoration area  sediment  spatial distribution  ecological risk