title: Practicability of monitoring soil Cd, Hg, and Pb pollution based on a geochemical survey in China.
abstract: Repeated visiting, i.e., sampling and analysis at two or more temporal points, is one of the important ways of monitoring soil heavy metal contamination. However, with the concern about the cost, determination of the number of samples and the temporal interval, and their capability to detect a certain change is a key technical problem to be solved. This depends on the spatial variation of the parameters in the monitoring units. The "National Multi-Purpose Regional Geochemical Survey" (NMPRGS) project in China, acquired the spatial distribution of heavy metals using a high density sampling method in the most arable regions in China. Based on soil Cd, Hg, and Pb data and taking administrative regions as the monitoring units, the number of samples and temporal intervals that may be used for monitoring soil heavy metal contamination were determined. It was found that there is a large variety of spatial variation of the elements in each NMPRGS region. This results in the difficulty in the determination of the minimum detectable changes (MDC), the number of samples, and temporal intervals for revisiting. This paper recommends a suitable set of the number of samples (nr) for each region under the balance of cost, practicability, and monitoring precision. Under nr, MDC values are acceptable for all the regions, and the minimum temporal intervals are practical with the range of 3.3-13.3 years.
authors.affiliation: School of Earth Sciences and Resources, China University of Geosciences, 100083, Beijing, People's Republic of China. Electronic address: xiaxueqi@cugb.edu.cn.
authors.forename: Xueqi
authors.initials: X
authors.lastname: Xia
authors.affiliation: School of Earth Sciences and Resources, China University of Geosciences, 100083, Beijing, People's Republic of China; National Research Center for Geoanalysis, Key Laboratory of Ecological Geochemistry, Ministry of Land and Resources, Beijing, 100037, People's Republic of China. Electronic address: zfyang01@126.com.
authors.forename: Zhongfang
authors.initials: Z
authors.lastname: Yang
authors.affiliation: School of Earth Sciences and Resources, China University of Geosciences, 100083, Beijing, People's Republic of China.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Li
authors.affiliation: School of Earth Sciences and Resources, China University of Geosciences, 100083, Beijing, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yu
authors.affiliation: School of Earth Sciences and Resources, China University of Geosciences, 100083, Beijing, People's Republic of China.
authors.forename: Qingye
authors.initials: Q
authors.lastname: Hou
authors.affiliation: School of Earth Sciences and Resources, China University of Geosciences, 100083, Beijing, People's Republic of China.
authors.forename: Admire Muchimamui
authors.initials: AM
authors.lastname: Mutelo
mesh_terms: D002104:Cadmium / Q000032:analysis; D002681:China; D004784:Environmental Monitoring / Q000379:methods*; D007854:Lead / Q000032:analysis; D008628:Mercury / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D019216:Metals, Heavy; D012989:Soil Pollutants; D002104:Cadmium; D007854:Lead; D008628:Mercury
keywords: Heavy metal; Monitoring; Soil; Spatial variation