Phytoavailability, human risk assessment and transfer characteristics of cadmium and zinc contamination from urban gardens in Kano, Nigeria

Abdu, N. and Agbenin, J.O. and Buerkert, A. (2011) Phytoavailability, human risk assessment and transfer characteristics of cadmium and zinc contamination from urban gardens in Kano, Nigeria. Journal of the Science of Food and Agriculture, 91 (15). pp. 2722-2730.

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Abstract

BACKGROUND: Quantitative data about phytoavailability and transfer into consumed plant parts for heavy metals in intensively managed urban vegetable production areas of sub-Saharan Africa are scarce. We therefore studied the transfer of zinc (Zn) and cadmium (Cd) from soil to the root and subsequent translocation to edible portions of four vegetables in six urban gardens. RESULTS: While respective diethylenetriaminepentaacetic acid (DTPA)-available Zn and Cd concentrations ranged from 18 to 66 mg kg-1 and from 0.19 to 0.35 mg kg-1, respectively, in soils, total Zn and Cd were 8.4-256 mg kg-1 and 0.04-1.7 mg kg-1 in shoot parts. Metal transfer factor (MTF) ratios were higher in Zn (0.2-0.9) than in Cd (0.1-0.6). Our data suggest that total Zn concentration in soil is a reliable indicator to assess its transfer from soil to crop in lettuce, carrot and parsley, while for Cd DTPA-extractable concentration may be used to estimate soil-crop transfer of Cd in amaranthus and carrot. Overall, Cd was more easily translocated to the aerial plant parts than Zn. CONCLUSION: Zinc and Cd accumulation by vegetables in our soils is mainly a metabolically controlled process. Such accumulation can contaminate the ecosystem but under our conditions intake and ingestion of these metals will likely have to occur over a prolonged period to experience health hazard.

Item Type: Article
Additional Information: The authors are grateful to the Volkswagen Stiftung, Hannover, Germany, for supporting this research financially under the Urban Food project within the collaborative program ‘Resources, their dynamics, and sustainability–capacity–development in comparative and integrated approaches’ (No. I/82 189).
Uncontrolled Keywords: health risk; root–shoot translocation; heavy metals; vegetables; soil pollution
Author Affiliation: Department of Soil Science, Faculty of Agriculture, Ahmadu Bello University, Zaria, Nigeria
Subjects: Atmosperic Science > Climatology
Soil Science and Microbiology
Plant Physiology and Biochemistry > Plant Physiology
Divisions: General
Depositing User: Mr Balakrishna Garadasu
Date Deposited: 06 Jun 2013 08:46
Last Modified: 06 Jun 2013 08:46
Official URL: http://dx.doi.org/10.1002/jsfa.4583
URI: http://eprints.icrisat.ac.in/id/eprint/10671

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