Premium
Soil factors controlling the expression of copper toxicity to plants in a wide range of European soils
Author(s) -
Rooney Corinne P.,
Zhao FangJie,
McGrath Steve P.
Publication year - 2006
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/04-602r.1
Subject(s) - soil water , chemistry , soil ph , bioavailability , environmental chemistry , shoot , cation exchange capacity , toxicity , agronomy , environmental science , soil science , biology , bioinformatics , organic chemistry
The impact of soil properties on metal bioavailability to plants is well recognized. However, the effect of soil bio‐availability parameters on toxicity threshold values for Cu in plants needs quantification. Eighteen European soils varying widely in soil properties were amended with CuCl 2 to obtain a range of seven concentrations including an unamended control. Two plant toxicity assays, barley root elongation (4 d) and tomato shoot growth (21 d after emergence), were performed on each soil under controlled environment conditions. The effective concentration of added Cu causing 50% inhibition (EC50) ranged from 36 to 536 mg/kg soil and from 22 to 851 mg/kg soil for barley root elongation and tomato shoot growth, respectively, representing variation in EC50 among soils of 15‐ and 39‐fold. Single regressions carried out between Cu toxicity threshold values and various soil properties showed that exchangeable calcium and soil cation exchange capacity (CEC; measured at soil pH) were the best single predictors for toxicity values from both plant tests. The inclusion of other soil properties, such as iron oxide concentration, soil pH, clay, or organic carbon content, further improved predictions. For risk assessment, we suggest that Cu toxicity threshold values (EC50) be normalized on the key soil property of CEC. If available, soil exchangeable calcium and iron oxide concentration would improve the normalization.