title: [Spatial variability of farmland heavy metals contents in Qianan City].
abstract: By the methods of geostatistics and GIS, this paper studied the spatial variability of Cu, Zn, Ni, Cr As, Hg, Cd and Pb contents in the farmland topsoil (0 -20 cm) of Qianan City, Hebei Province. The results showed that the average contents of test metals were under the secondary standard of environmental quality standard for soil (GB 15618-1995), and belonged to moderate variability. The theoretical models of semi-variance of Cu, Zn, Ni, Cr and As contents fitted exponential models, and their spatial correlations were strongly spatial dependence; while the theoretical models of Hg and Cd contents fitted spherical models, and their spatial correlations were moderately spatial dependence. The Pb content had pure nugget effect, and was weakly spatial dependence. In whole research scale, Pb content had lasting variability, while the other seven heavy metals contents had the spatial variability mainly caused by their spatial correlation parts. The ranges of heavy metals spatial correlations were about 11 km to 20 km. The Kriging' s interpolation of Cu, Zn, Ni, Cr, Hg, As and Cd contents showed that their contents were higher in northern mountainous area, but lower in mid basin.
authors.affiliation: Lnstitute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021, China. wangbo04@mails.gucas.ac.cn
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.forename: Yuanzhong
authors.initials: Y
authors.lastname: Wang
authors.forename: Dongmei
authors.initials: D
authors.lastname: Li
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Gao
authors.forename: Renzhao
authors.initials: R
authors.lastname: Mao
mesh_terms: D002681:China; D003300:Copper / Q000032:analysis; D018556:Crops, Agricultural / Q000254:growth & development*; D004784:Environmental Monitoring / Q000379:methods; D040362:Geographic Information Systems; D019216:Metals, Heavy / Q000032:analysis*; D009532:Nickel / Q000032:analysis; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D015032:Zinc / Q000032:analysis
chemical_list: D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; D003300:Copper; D009532:Nickel; D015032:Zinc