title: Transfer model of lead in soil-carrot (Daucus carota L.) system and food safety thresholds in soil.
abstract: 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 CaCl2 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.
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.
authors.forename: Changfeng
authors.initials: C
authors.lastname: Ding
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Li
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.|University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Taolin
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.|University of Chinese Academy of Sciences, Beijing, China.|Jiangxi Key Laboratory of Ecological Research of Red Soil, Ecological Experimental Station of Red Soil, Chinese Academy of Sciences, Yingtan, China.
authors.forename: Xingxiang
authors.initials: X
authors.lastname: Wang
mesh_terms: D002412:Cations / Q000737:chemistry; D018552:Daucus carota / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D059022:Food Safety; D017752:Greenhouse Effect; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000032:analysis* / Q000633:toxicity; D008962:Models, Theoretical; D012989:Soil Pollutants / Q000032:analysis* / Q000633:toxicity; D013054:Spectrophotometry, Atomic
chemical_list: D002412:Cations; D012989:Soil Pollutants; D007854:Lead
keywords: Metal uptake; Plants; Prediction models; Soil contamination; Soil thresholds