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Transfer model of lead in soil–carrot ( Daucus carota L.) system and food safety thresholds in soil
Author(s) -
Ding Changfeng,
Li Xiaogang,
Zhang Taolin,
Wang Xingxiang
Publication year - 2015
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 - 10.1002/etc.3031
Subject(s) - daucus carota , transfer factor , soil water , chemistry , cation exchange capacity , environmental science , soil quality , environmental chemistry , soil test , soil science , agronomy , biology , immunology
Reliable empirical models describing lead (Pb) transfer in soil–plant systems are needed to improve soil environmental quality standards. A greenhouse experiment was conducted to develop soil–plant transfer models to predict Pb concentrations in carrot ( Daucus carota L.). Soil thresholds for food safety were then derived inversely using the prediction model in view of the maximum allowable limit for Pb in food. The 2 most important soil properties that influenced carrot Pb uptake factor (ratio of Pb concentration in carrot to that in soil) were soil pH and cation exchange capacity (CEC), as revealed by path analysis. Stepwise multiple linear regression models were based on soil properties and the pseudo total (aqua regia) or extractable (0.01 M CaCl 2 and 0.005 M diethylenetriamine pentaacetic acid) soil Pb concentrations. Carrot Pb contents were best explained by the pseudo total soil Pb concentrations in combination with soil pH and CEC, with the percentage of variation explained being up to 93%. The derived soil thresholds based on added Pb (total soil Pb with the geogenic background part subtracted) have the advantage of better applicability to soils with high natural background Pb levels. Validation of the thresholds against data from field trials and literature studies indicated that the proposed thresholds are reasonable and reliable. Environ Toxicol Chem 2015;34:2078–2086. © 2015 SETAC