Cadmium uptake in radish (Raphanus sativus L.) and surficial contamination: implications for food safety and local soil management
Soil management strategies for agricultural lands contaminated with potentially toxic trace elements, especially cadmium (Cd), are still inadequate and require a precise identification of soils that are not s afe for growing crops. Key soil variables need to be identified to connect soil safety with food safety by reliable models.
Materials and methods
Soil variables that affect concentrations of metals in different portions of radish, Raphanus sativus L., were examined as part of a greenhouse experiment. 0.01 M di-sodium-di-hydroxy-ethylenediamine-tretra-acetic acid (Na2H2EDTA) solution was used in a strong rinsing experiment. Cd soil-radish relationships were derived by different modeling approaches and were used to develop local risk screening values for Cd in soil.
Results and discussion
The current lab washing procedures readily remove surface Cd adherence but are not adequate to remove surface-deposited lead (Pb), thus overestimating bioaccumulation in plants by mean 111%. Shoot and root tissue Cd concentration in fresh weight basis do not present a significant difference and can be precisely predicted by regression models using different Cd pools and soil pH. Preferably a polynomial surface model can be used in developing local rick screening values that yield concentrations of Cd in radish at or below the Chinese food quality standard of 0.1 mg kg−1 (fresh weight).
The bioaccumulation of Cd in radish depends on the Cd bioavailability in soil. But for Pb, surficial particle contamination masks the realistic bioaccumulation. We also demonstrated the usefulness of the polynomial surface model to develop local soil protection guidelines that are helpful to local farmers for proper soil management and avoidance of Cd exceedance in food.
KeywordsCd Bioavailability pH Potentially toxic metals Soil criteria Soil extraction tests
This work was funded by the STS Program of the Chinese Academy of Sciences (no. KFJ-STS-ZDTP-005) and the National Environmental Protection Public Welfare Industry Targeted Research Fund (201409042).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no competing interests.
- Gong ZT, Lei WJ, Cao SG (1994) Systematic classification of arid soils in China. Progress Soil Sci 22(02):45–47Google Scholar
- Lu RK (2000) Analytical methods of soil and agricultural chemistry. China Agricultural Science and Technology Press, Beijing, pp 107–240Google Scholar
- Luo YM (2018) Regional difference in soil pollution and strategy of soil zonal governace and remediation in China. Chin Sci Bull 2:145–152Google Scholar
- Ministry of Ecology and Environment (1997). Soil quality—determination of Lead, cadmium—graphite furnace atomic adsorption spectrophotometry (GB/T 17141). T. a. S. (Ed) Department of Science, ChinaGoogle Scholar
- Singh S, Zacharias M, Kalpana S, Mishra S (2012) Heavy metals accumulation and distribution pattern in different vegetable crops. J Environ Chem Ecotoxicol 4(4):75–81Google Scholar
- Tchounwou PB, Yedjou CG, Patlolla AK, Sutton DJ (2012) Heavy metal toxicity and the environment. In: Molecular, Clinical and Environmental Toxicology Springer, pp 133–164Google Scholar