Predictors of Copper Phytotoxicity in Mining-Contaminated Soils: Findings of Several Years of Research

— This paper summarizes the findings of several years of the authors’ research on copper phytotoxicity in soils contaminated by copper mining industry in the Valparaiso region of central Chile. Although soils under study were contaminated by several elements, copper was found to be the most important factor limiting plant growth, while the other elements had no statistically significant effect. The concentration of copper in the 0.1 M KNO 3 extract proved to be the best indicator of phytotoxicity compared to the total copper content or the activity of free Cu 2+ ions in the same extract. The total copper content, pH, and dissolved organic carbon concentration were in turn found to be the most important variables in predicting copper concentration and copper ion activity in the 0.1 M KNO 3 extract.