Compost application affects metal uptake in plants grown in urban garden soils and potential human health risk

• Published in: Journal of soils and sediments Vol. 11; no. 5; pp. 815 - 829
• Main Authors: Murray, Hollydawn, Pinchin, Trevor A., Macfie, Sheila M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-07-2011; Springer Nature B.V
• Subjects: Bioaccumulation; Biological magnification; Cadmium; Composts; Daucus; Daucus carota; Earth and Environmental Science; Environment; Environmental Physics; Flowers & plants; Fulvic acids; Gardens & gardening; Health risks; Humic acids; Lactuca sativa; Metal concentrations; Metals; Organic matter; Phaseolus vulgaris; Risk factors; Sec 5 • Soil and Landscape Ecology • Research Article; Soil amendment; Soil Science & Conservation; Soils; Urban areas; Vegetables; Organic matter; Fulvic acid; Metal contamination; Risk assessment; Humic acid; Urban gardens
• ISSN: 1439-0108; 1614-7480
• DOI: 10.1007/s11368-011-0359-y

Purpose
This study explores the effect of varying organic matter content on the potential human health risk of consuming vegetables grown in urban garden soils.
Materials and methods
Metal accumulation among edible tissues of green bean (
Phaseolus vulgaris
L.), lettuce (
Lactuca sativa
L.), and carrot (
Daucus carota
L.) was determined for plants grown in five urban garden soils amended with 0%, 9%, or 25% (
v
/
v
) compost. Potential risk to human health was assessed by calculating a bioconcentration factor and a hazard quotient.
Results and discussion
Overall, the consumption of lettuce and green bean pods grown in some urban gardens posed a potential human health risk due to unacceptably high concentrations of cadmium or lead. In many cases, compost amendment increased the accumulation of metals in the vegetables. Even in soils considered uncontaminated by current guidelines, some hazard quotients exceeded the threshold value of 1. The compost used in this study had a high fulvic acid to humic acid ratio, which may explain increased concentrations of metals in plants grown in compost-amended soils.
Conclusions
These results indicate a need to include soil characteristics, specifically organic matter quality, when setting threshold criteria for metal content of urban garden soils.