Appleton J.D., Rawlings B.G., Thornton I. 2008. National-scale estimation of potentially harmful element ambient background concentrations in topsoil using parent material classified soil: stream–sediment relationships. Applied Geochemistry 23: 2596–2611. Baize D., Sterckeman T. 2001. Of the necessity of knowledge of the natural pedogeochemical background content in the evaluation of the contamination of soils by trace elements. The Science of the Total Environment 264: 127–139. Bing H., Wu Y., Sun Z., Yao S. 2011. Historical trends of heavy metal contamination and their sources in lacustrine sediment from Xijiu Lake, Taihu Lake Catchment, China. Journal of Environmental Sciences 23(10);1671–1678. Gałuszka A. 2006. Geochemical Background of Selected Trace Elements in Mosses Pleurozium schreberi (Brid.) Mitt. And Hylocomium splendens (Hedw.) B.S.G. from Wigierski National Park. Polish Journal of Environmental Studies, 15 (2a): 72–77. Gałuszka A. 2007. A review of geochemical background concepts and an example using data from Poland. Environmental Geology, 52: 861–870. Gałuszka A., Migaszewski Z.M. 2011. Geochemical background – an environmental perspective. Mineralogia, 42(1): 7–17. Hakanson L. 1980. An ecological risk index for aqatic pollution control. A sedimentological approach. Water Research, 14, 8: 975–1001. Hawkes H., Webb J.E. 1962. Geochemistry in mineral exploration. Harper, NY, 415. Kabata-Pendias, Piotrowska M., Witek T. 1993. Ocena stopnia zanieczyszczenia gleb i roślin metalami ciężkimi i siarką. Ramowe wytyczne dla rolnictwa. IUNG, Puławy. Kicińska A. 2012. Zróżnicowanie geochemiczne obszaru Beskidu Sądeckiego i jego wpływ na obieg wybranych pierwiastków. Wydawnictwo AGH, Kraków. [In Polish] Kicińska A. 2016. Assessment of the road traffic impact on accumulation of selected elements in soils developed on Krynica and Bystrica subunit (Magura Nappe, Polish Outer Carpathians), Carpathian J. of Earth and Environmental Science, 11, 1: 245–254. Matschullat J., Ottenstein R., Reimann C. 2000. Geochemical background – can we calculate it? Environmental Geology 39 (9). Muller G. 1981. Die Schwermetallbelstung der sedimente des Neckars und Seiner Nebenfl usse: eine Bestandsanfunahme. Chemiker-Zeitung, 105: 156–164. PN-ENISO19258:2011. Soil quality-guidance on the determination of background values. Regulation of Minister of Environment on 1 September 2016 how to conduct the assessment of contamination of the earth surface (Dz. U. 2016 poz. 1395). Reimann C., Filzmoser P., Garrett R.G. 2005. Background and threshold: critical comparison of methods of determination. Science of the Total Environment 346: 1–16. Reimann C., Filzmoser P. 1999. Normal and lognormal data distribution in geochemistry: death of a myth. Consequences for the statistical treatment of geochemical and environmental data. Environmental Geology 39(9). Reimann C., Garrett R.G. 2005. Geochemical background – concept and reality. Science of the Total Environment 350, 12–27. Thi Thu Dung T., Cappuyns V., Swennen R., Ky Phung N. 2013. From geochemical background determination to pollution assessment of heavy metals in sediments and soils. Reviews in Environmental Science and Biotechnology, 12: 335–353. Tukey J.W. 1977. Exploratory Data Analysis. Addison-Wesley, Boston.