Pedosphere 25(6): 825--833, 2015
ISSN 1002-0160/CN 32-1315/P
©2015 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Using DGT to assess cadmium bioavailability to ryegrass as influenced by soil properties |
SONG Ning-Ning1,2, WANG Fang-Li2, MA Yi-Bing3 and TANG Shi-Rong2 |
1Qingdao Engineering Research Center for Rural Environment, Qingdao Agricultural University, Qingdao 266109 (China)
2Centre for Research in Ecotoxicology and Environmental Remediation, Agro-Environmental Protection Institute, Ministry of Agriculture, Tianjin 300191 (China)
3School of Resources and Environment, University of Jinan, Jinan 250022 (China) |
| ABSTRACT |
| A generally accepted method for predicting the bioavailability and transfer of cadmium (Cd) from soil to plants has not yet been established. In this study, the diffusive gradients in thin films (DGT) and conventional extraction methods for metal fractions were used to investigate how effective these methods were at predicting Cd bioavailability to ryegrass (Lolium perenne) and to assess whether these holistic variables were independent of the soil property variables. The influences of soil properties on the predictive capabilities of the different methods were evaluated using multivariate statistics. The Cd concentrations in the shoots and roots of ryegrass correlated more closely with the effective Cd concentration measured by DGT (CE), compared with those with soil total Cd, pore water Cd, and ethylenediaminetetraacetic acid disodium salt (Na2EDTA)- and acetic acid (HOAc)-extractable Cd. When soil properties were included in a stepwise multiple linear regression, Cd transfer to L. perenne was negatively influenced by pH and positively influenced by organic matter (OM). The multivariate statistics showed that the adjusted correlation coefficients for the plots involving soil total Cd, pore water Cd, and Na2EDTA- and HOAc-extractable Cd had been significantly improved after considering the influences of soil properties, which suggested that these methods were pH and OM dependent. For CE, the relationship was pH independent or only dependent in strongly acidic soils. These results suggested that the main soil factors affecting bioavailability had the lowest impact on the DGT technique. Therefore, the DGT technique provided significant advantages over conventional methods when assessing Cd bioavailability. |
| Key Words: conventional extraction methods, diffusive gradients in thin films, effective Cd concentration, organic matter, porewater |
| Citation: Song, N. N., Wang, F. L., Ma, Y. B. and Tang, S. R. 2015. Using DGT to assess cadmium bioavailability to ryegrass as influenced by soil properties. Pedosphere. 25(6): 825-833. |
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