• 关键词：新月形沙丘  降尘  重金属  绿洲  生态风险

• 基金项目：国家自然科学基金(No.41301302,41301303);水利部公益性行业科研专项经费(No.201401084);中国水科院科研专项项目(No.MK2013J08)

• 陈新闯
• 山东农业大学林学院/山东省土壤侵蚀与生态修复重点实验室/泰山森林生态站, 泰安 271018

• 郭建英
• 水利部牧区水利科学研究所, 呼和浩特 010020

• 董智
• 山东农业大学林学院/山东省土壤侵蚀与生态修复重点实验室/泰山森林生态站, 泰安 271018

• 李红丽
• 山东农业大学林学院/山东省土壤侵蚀与生态修复重点实验室/泰山森林生态站, 泰安 271018

• 李锦荣
• 水利部牧区水利科学研究所, 呼和浩特 010020

• 王合云
• 山东农业大学林学院/山东省土壤侵蚀与生态修复重点实验室/泰山森林生态站, 泰安 271018

• 摘要：本文以乌兰布和沙漠绿洲边缘工业化城市乌海市下风向典型新月形沙丘为研究对象,分析了新月形沙丘各部位0~10 cm沙物质、沙丘前50 m处大气降尘的粒度及重金属元素变化特征,探讨了重金属物质的来源及其与粒径的相关性,评价了重金属的潜在生态风险.结果表明:沙丘各部位沉积物粒度均以细砂为主,较对照沙丘极细砂含量增高而中砂含量减少.而降尘主要以极细砂、粉粒为主,降尘在沙丘表面的沉降堆积使沙丘表层沙物质细化.沙丘与降尘的重金属含量均为Fe >Mn >Cr >Zn >Cu;Mn、Cu、Zn、Cr含量均高于背景值且发生富集.Mn、Zn含量在空间分布上呈中等变异;Fe、Cu含量在空间分布上为高度变异.Mn、Zn、Cu含量与细颗粒含量呈显著正相关,Zn、Cu含量与中砂含量呈负相关,Fe含量与细砂和中砂含量均呈负相关.Cu、Zn、Cr为人为污染因子,Mn、Fe为自然源因子,但Cr、Mn、Fe又受到自然地质背景和人类活动的共同控制.乌海市下风向新月形沙丘属于低生态风险状态,为轻度污染,需加强废气的治理控制以防重金属污染的进一步加深.

• Abstract：The barchan dunes on the leeward near Wuhai city, an industrial city located in the edge of Ulan Buh desert oasis, was studied for the variation of heavy metals and grain size of surface sediments (0~10 cm) from the barchans and dustfall (50 m in front of dunes). The correlation between the heavy metals and the particle sizes was analyzed and the sources of heavy metals and those potential ecological risk assessments were discussed. Results show that: the grain of dunes were mainly fine sand, the content of ultra-fine sand was higher, but the medium sand was less than those of control (that was deep in the desert). The particle of most dust belonged to ultra-fine sand and silt, dust deposition made grain size refinement on the surface of dunes. The heavy metals contents of both dunes and dustfall were in the following order: Fe>Mn>Cr>Zn>Cu. The contents of Mn, Cu, Zn, Cr were higher than those of control dune and exhibit an enriching trend. Mn, Zn content show moderate variation (15%36%) in spatial distribution. The contents of Mn, Zn, Cu were positively correlated with the content of fine particle, but Zn、Cu were in negative correlation with the content of medium sand, and Fe was in negative correlation with the content of both fine and medium sand. The enrichment of Cu, Zn, Cr was attributed to artificial factors, and the increase of Mn, Fe were due to natural factors, but the contents of Cr, Mn, Fe were controlled by both of the environmental and human activities. In all, barchans in this study were slight polluted and in the state of low ecological risk. The control of exhaust emissions should be strengthened in order to avoid the further heavy metals pollution.

• Key words：barchan dune  dustfall  heavy metal  oasis  ecological risk

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