Tungstate adsorption onto Italian soils with different characteristics Gianniantonio Petruzzelli & Francesca Pedron Received: 3 April 2017 /Accepted: 20 June 2017 # Springer International Publishing AG 2017 Abstract The study of tungsten in the environment is currently of considerable interest because of the grow- ing concerns resulting from its possible toxicity and carcinogenicity. Adsorption reactions are some of the fundamental processes governing the fate and transport of tungsten compounds in soil. This paper reports data on the adsorption of tungstate ions in three different Italian soils, which are characteristic of the Mediterra- nean region. The results show that pH is the most important factor governing the adsorption of tungstate in these soils. The data interpreted according to the Langmuir equation show that the maximum value of adsorption is approximately 30 mmol kg -1 for the most acidic soil (pH = 4.50) and approximately 9 mmol kg -1 for the most basic soil (pH = 7.40). In addition, soil organic matter is shown to play a fundamental role in adsorption processes, which are favored in soils with a higher organic matter content. The data could contribute to a better understanding of the behavior of tungsten compounds in Italian soils for which current knowledge is very scarce, also in view of environmental regula- tions, which are currently lacking. Keywords Tungstate . Batch adsorption . Langmuir equation . Soil characteristics Introduction Tungsten (W) is a relatively rare transition metal in the earth’ s crust which occurs naturally in soils, generally in small concentrations in the range of 0.2–2.4 mg kg -1 (Koutsospyros et al. 2006). Due to its specific properties such as high melting point and corrosion resistance, tungsten is used in many industrial activities ranging from the production of commonly used objects to high- tech components (Koutsospyros et al. 2011). Chemical and metallurgical industries use more than 33,000 t of tungsten annually, while the global mine produc- tion is estimated to be over 60,000 t per year (Shedd 2011). For a long time, tungsten was considered to be sub- stantially inert and devoid of adverse effects on humans and the environment. Recently, this view changed (Kelly et al. 2013; Laulicht et al. 2015), and tungsten compounds have been found to be soluble under certain environmental conditions, which is of increasing con- cern due to several military applications (Clausen and Korte 2009). Dermatas et al. in 2004 reported on the environmental relevance of tungsten dissolution from military munitions. The US EPA reports that about 85 million rounds of tungsten/nylon bullets were produced under the US Army’ s Green Armament Technology Program as alternatives to lead-based munition (US EPA 2014). Due to concerns arising from the adverse effects of depleted uranium, tungsten has also replaced uranium in many military applications (Koutsospyros et al. 2006). In the evaluation of tungsten in soils at military installations, a concentration of up to 2080 mg kg -1 was discovered in surface soils at Camp Environ Monit Assess (2017) 189:379 DOI 10.1007/s10661-017-6088-y G. Petruzzelli (*) : F. Pedron Institute of Ecosystem Studies, National Council of Research, Pisa, Italy e-mail: petruzzelli@ise.cnr.it