Spatial Distribution and Potential Ecological Risk (PER)of Heavy Metals in Apple Orchards of Weibei Area, the Loess Plateau
From the apple orchards in the Weibei area of the southern Loess Plateau of China, 277 topsoil samples were collected to measure the contents of arsenic (As), copper (Cu), cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb). A combination of statistical and geostatistical method was applied to identify concentrations of heavy metals and to demonstrate the spatial distribution of these metals in the studied regions. The results indicated that the average contents of Hg, Cd, Pb, As, Cr and Cu in soil were 0.055, 0.121, 20.561, 11.895, 59.134, 24.110 mg kg-1, respectively, and were higher than their corresponding background values. The average contents of the metals presented moderate coefficients of variance, indicating that their enrichment was, to a certain extant, influenced by apple orchard managements such as fertilization and chemical spray. Geostatistical analysis showed that the Nugget/Sill ratios of six heavy metals were lower than 25％, indicating that distribution of heavy metals had stronger spatial dependence because geological factors played a dominant role. Interpolation maps of the six metals showed that Hg, Cd, Pb, As and Cr had a similar distribution, high concentrations in the central and southwest area and low concentrations in the north and southeast area, while Cu concentrations showed a different distribution, low in the central area and high in the north and southwest area. A single potential ecological risk index of these six metals in soil was Hg > Cd > Pb > As > Cu > Cr. Comprehensive potential ecological risk showed that more than half samples (67％) were in medium and low degree of potential ecological risk, implying that most parts of the studied area did not suffer from sever risk and 33％ of samples presented high level of potential risk, which should be monitored in the future.
Heavy metals Geostatistics Spatial distribution Potential ecological risk Apple orchard The Loess Plateau
Huike Li Kekuan Hu Yizhen Wan Zhengyang Zhao Guowei Pang
College of Environment and Resource, Northwest A&F University, Yangling, Shaanxi, 712100, China College of Horticulture, Northwest A&F University, Yangling ,Shaanxi,712100, China Institute of Soil and Water Conservation, Chinese Academy of Sciences, Yangling, Shaanxi ,712100
国际会议
西安
英文
1002-1008
2010-10-11（万方平台首次上网日期，不代表论文的发表时间）