Many human activities lead to soil contamination by heavy metals and polluted areas must undergo the remediation process. Among various techniques, immobilisation with organic amendments is gaining popularity, as it reduces the  bioavailability of heavy metal. The main aim of this study has been to evaluate the applicability of compost as stabilisation material to reduce metal bioavailability. Another goal has been to determine practical applicability of developed factors as a reliable and helpful indicator of metal-soil-plant interactions. The transfer of metals in environment was described by the bioconcentration factors (BCFT, BCFA) and the contamination level coefficient (CCL). Bioconcentration factors were calculated on the basis of total and bioavailable amounts of heavy metals. The investigations were carried out under greenhouse conditions with two soils (light and medium) with and without biowaste compost amendment and two test plants (winter barley and white mustard) at a simulated contamination with Cu (doses of 25 and 50 mg∙kg-1) and Zn (doses of 100 and 200 mg∙kg-1). It was demonstrated that the proposed BCFT, BCFA and CCL are reliable and helpful indicators of phytotoxicity. Regardless of the experimental factors, BCFT ranged from 0.1 to 1.5, BCFA from 0.5 to 8.8 and CCL from 1.0 to 4.0. Additionally, the presented threshold of toxicity, determined on the basis of the above indicators, facilitates the interpretation of metal-soil-plant interactions. The results proved that compost is a valuable organic amendment, which can significantly reduce metal bioavailability. Moreover, the proposed bioconcentration factor (BCFT, BCFA) and the contamination level coefficient (CCL) seem to be useful tools to assess soil contamination in relation to environment phytotoxicity. The two-sided F-Snedecor test and Student's t-test were applied as statistical tools for calculation and interpretation of the results. The visualisation of data was achieved via violin plots.  

24.4.2019