Farmyard manures: the major agronomic sources of heavy metals in the Philippi Horticultural Area in the Western Cape Province of South Africa.
Heavy metal toxicity in agro-ecosystems is a global problem. Recently, it has been indicated that the soils used for agriculture and the fresh produce grown on these soils in the Philippi Horticultural Area (PHA) contains heavy metals exceeding the maximum permissible concentrations thereof in South Africa. This study was therefore aimed at evaluating the concentrations of heavy metals in the soils and vegetables produced in the PHA, as well as to determine the major agronomic sources of these metals in this area. Cu, Pb, and Zn concentrations in the soils exceeded the maximum permissible concentrations of 6.6, 6.6, and 46 mg/kg, respectively. Cd, Pb, and Zn concentrations in the vegetables also exceeded the maximum permissible concentrations of 0.1, 0.5, and 40 mg/kg, respectively. The biggest agronomic contributors of these heavy metals to the soils in the PHA were found to be the farmyard manures. Knowing what the major sources of these heavy metals are, it is important to determine ways to mitigate the inputs thereof, as well as to remove existing concentrations from the soils without contaminating the groundwater resources in the area.
Department of Biodiversity and Conservation Biology, University of the Western Cape, Private Bag x 17, Bellville, 7535, South Africa.
Marÿke
M
Malan
Department of Biodiversity and Conservation Biology, University of the Western Cape, Private Bag x 17, Bellville, 7535, South Africa. francuoismuller@gmail.com.|Agricultural Research Council-Animal Production Institute (ARC-API), University of the Western Cape, Private Bag x17, Bellville, 7535, South Africa. francuoismuller@gmail.com.
Francuois
F
Müller
Department of Biodiversity and Conservation Biology, University of the Western Cape, Private Bag x 17, Bellville, 7535, South Africa.
Lincoln
L
Raitt
Department of Biodiversity and Conservation Biology, University of the Western Cape, Private Bag x 17, Bellville, 7535, South Africa.
Johannes
J
Aalbers
Department of Biodiversity and Conservation Biology, University of the Western Cape, Private Bag x 17, Bellville, 7535, South Africa.
Lilburne
L
Cyster
Laboratory of Aquatic Ecology, Evolution and Conservation, University of Leuven (KU Leuven), Charles Deberiotstraat 32, Box 2439, B-3000, Leuven, Belgium.
Luc
L
Brendonck
D000383:Agriculture; D004784:Environmental Monitoring; D008372:Manure / Q000032:analysis*; D019216:Metals, Heavy / Q000032:analysis*; D012987:Soil; D012989:Soil Pollutants / Q000032:analysis*; D013019:South Africa; D014675:Vegetables
D008372:Manure; D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants
Cadmium; Copper; Lead; Soil and vegetable contamination; Zinc