Sampling, Analytical and Data Handling Protocols for the North American Soil Geochemical Landscape Project

One aim of the North American Soil Geochemical Project is to develop and use a continental-scale framework, including a set of protocols, for generating soil geochemical data. The collection of the 13, 615 samples is based on a spatially stratified random design - the generalized random tessellation stratified (GRTS) sampling. Sampling is horizon-based (0-5 cm "public health" layer, A, C). The <2.00 mm fraction of all samples is being analyzed for 42 elements by ICP-AES/MS after a 4-acid dissolution, Hg by cold-vapour AAS, Se by hydride AAS after an acid digestion and organic and inorganic carbon using a LECO analyzer. Additional sampling and analyses are being undertaken at tri-national sites to meet the needs of individual countries or participant groups. For example, in Canada, the <2.00 mm and <0.063 mm fractions of A-, B- and C- horizon samples are being analyzed following the US-EPA 3050B protocol and soil gas radon data is being routinely collected. Data obtained from the NASGL Project will be stored in a database containing essential metadata that fully describe the nature of the samples, sample sites and analytical values. The data will also be maintained in a geographic information system that will permit geospatial visualization and spatial management of the data. The database will be stored in a normalized form for efficient management. Views and tables along with necessary SQL programming statements will permit users to query and create their own views of the data. All field, laboratory, and data handling procedures are being documented in minute detail. A comprehensive protocols manual is being developed that is in digital form and web accessible. It consists of a series of modules or appendices that will be updated as needed.