Pedosphere 27(3): 389–406, 2017 doi:10.1016/S1002-0160(17)60337-0 ISSN 1002-0160/CN 32-1315/P c ⃝ 2017 Soil Science Society of China Published by Elsevier B.V. and Science Press Assessment of Methods for Determining Bioavailability of Trace Elements in Soils: A Review Jurate KUMPIENE 1 , Laura GIAGNONI 2 , Bernd MARSCHNER 3 , S´ebastien DENYS 4 , Michel MENCH 5 , Kristin ADRIAENSEN 6 , Jaco VANGRONSVELD 7 , Markus PUSCHENREITER 8 and Giancarlo RENELLA 2,* 1 Waste Science & Technology, Lule˚a University of Technology, 97187 Lule˚a (Sweden) 2 Department of Agrifood Production and Environmental Sciences, University of Florence, 50144 Florence (Italy) 3 Ruhr-Universit¨at Bochum, 44801 Bochum (Germany) 4 Joint Research Unit (UMR) Biodiversity, Genes & Communities (BIOGECO), French National Institute for Agricultural Research (INRA), 33405 Bordeaux (France) 5 Agence Nationale de S´ecurit´e Sanitaire (Anses), 94700 Paris (France) 6 i-CLEANTECH Vlaanderen, 3530 Houthalen-Helchteren (Belgium) 7 Hasselt University, Centre for Environmental Sciences, 3590 Diepenbeek (Belgium) 8 University of Natural Resources and Life Sciences Vienna, 3430 Tulln (Austria) (Received March 29, 2017; revised May 6, 2017) ABSTRACT Trace element-contaminated soils (TECSs) are one of the consequences of the past industrial development worldwide. Excessive exposure to trace elements (TEs) represents a permanent threat to ecosystems and humans worldwide owing to the capacity of metal(loid)s to cross the cell membranes of living organisms and of human epithelia, and their interference with cell metabolism. Quantification of TE bioavailability in soils is complicated due to the polyphasic and reactive nature of soil constituents. To unravel critical factors controlling soil TE bioavailability and to quantify the ecological toxicity of TECSs, TEs are pivotal for evaluating excessive exposure or deficiencies and controlling the ecological risks. While current knowledge on TE bioavailability and related cumulative consequences is growing, the lack of an integrated use of this concept still hinders its utilization for a more holistic view of ecosystem vulnerability and risks for human health. Bioavailability is not generally included in models for decision making in the appraisal of TECS remediation options. In this review we describe the methods for determining the TE bioavailability and technological developments, gaps in current knowledge, and research needed to better understand how TE bioavailability can be controlled by sustainable TECS management altering key chemical properties, which would allow policy decisions for environmental protection and risk management. Key Words: bioaccessibility, bioavailability, biosensors, chemical extractions, contaminated soils, metalloids, metals Citation: Kumpiene J, Giagnoni L, Marschner B, Denys S, Mench M, Adriaensen K, Vangronsveld J, Puschenreiter M, Renella G. 2017. Assessment of methods for determining bioavailability of trace elements in soils: A review. Pedosphere. 27(3): 389–406. INTRODUCTION Trace element-contaminated soils (TECSs) are usu- ally associated with industrial development, long-term intensive agriculture, and rapid urbanization. Out of the 2.4 × 10 6 contaminated sites in the European U- nion (EU), at least 3.4 × 10 5 would require urgent remediation actions (Panagos et al., 2013), as well as at least 6.3 × 10 6 km 2 of land throughout China (Hu et al., 2014), including about 20% of farmland soil, a proportion that may influence the food safety and se- curity in this country. Common trace elements (TEs) generally exceeding their background concentrations and national guide- line values in TECSs are As, Cd, Cr, Cu, Hg, Mo, Ni, Pb, and Zn. However several other metals (e.g., Tl) and metalloids (e.g., Se, Sn, and Sb) frequently occur at higher concentrations in TECSs than their back- ground levels, although they are less studied because not subjected to mandatory thresholds. The large number of identified contaminated sites and the complexity of TECSs require the search for strategies to prioritise the remediation efforts. This process is often done by the risk assessment of a con- taminated site in relation to the ecosystems and hu- man health. Determination of total soil TEs and other soil contaminants, notably based on past activities and used chemicals, is the first step in initial risk assess- ment, although it is also important in the residual risk assessment. The environmental legislations in many co- ∗ Corresponding author. E-mail: giancarlo.renella@unifi.it.