Assessment of Heavy Metal Contamination in Soils around Cassava Processing Mills in Sub- Urban Areas of Delta State, Southern Nigeria

The concentrations, contamination/pollution index, anthropogenic input and enrichment factors for metals in soil in the vicinity of cassava processing mills in sub-urban areas of Delta State of Nigeria were examined. The concentrations of metals in all sites and depths ranged from 0.1 to 383.2 mg kg-1 for Mn, 4.0 to 11.3 mg kg-1 for Ni, 1746.4 to 2839.6 mg kg-1 for Fe, 0.01 to 3.70 mg kg-1 for Cr, 3.7 to 29.5 mg kg-1 for Cu, 21.9 to 97.3 mg kg-1 for Zn, 0.01 to 1.60 mg kg-1 for Cd and <0.01 to <0.01 mg kg-1 for Pb. The concentrations of metals at these sites were below the Department of Petroleum Resources target values for metals in soils except for Cd in some sites. A significant fraction of these metals aroses from anthropogenic sources. The percent anthropogenic fraction of metals in the soil follow the order Cd > Zn > Ni > Cu > Fe > Cr > Pb.Keywords: Anthropogenic input, cassava, heavy metals, pollution inde

Assessment of pollution trend of heavy metals in soils in the vicinity of Nigerian Gas Company in Ughelli, Delta State

Topsoil and subsoil obtained in the vicinity of the Nigerian Gas Company were digested and analysed for some selected trace metals using atomic absorption spectrophotometer of model pye unicam SP 2900. The trace metals determined include nickel, copper, iron, barium, lead, cadmium and zinc respectively. The analytical results obtained revealed that the aforementioned trace metals were detected and metal concentrations were highly varied for both topsoil and subsoil. Soil samples (topsoil and subsoil) showedsignificant higher metal concentrations when compared with those of the background samples. The mean concentrations of nickel, iron, barium, lead and cadmium in topsoil (0-15 cm) were lower than those values obtained in subsoil (15-30 cm). The results of this study were also compared with other similar studies within Nigeria. The results indicate significant enrichment of trace metals in the studied areas. The metal enrichment reported in this study is traceable to petroleum activities in the Niger Delta region

Heavy metal contamination of some vegetables and spices in Nigeria

Analytical results are presented for the determination of Cd, Pb, Cu, Cr, Ni, Fe and Zn contents in some species of fresh vegetables and spices (Abelmoschus esculentus, Amarathus spinosis, Cucumis sativa, Taliniumtriangulare, Daucus carrota, Phaseolus vulgaris, Vernonia amygdalina, Piper nigrum, Lycopersicon esculentum, Telfaria occidentalis, Cochorus olitorius, Allium cepa, Brassica oleraca Tephrosia densiflora, Capsicum annum, Citrullus vulgaris, Tetrapleura tetraptera, Anisophylea spp Piper guineensis, Mynstica fragrans, Aframomum melegueta and Allium sativum ) collected from markets in Warri and its environs (Nigeria) between February to May, 2007. The mean concentrations of these elements in vegetables and spices ranged from 0.01-11.5 mg.kg-1 for Pb; 0.01-0.2 mgkg-1 for Cu; 0.17-4.2 mg.kg-1 for Cd, 0.01 mg.kg-1 for Cr; 0.01-16.8 mg.kg-1 for Ni; 30-44.02 mg.kg-1 for Zn; 4.08-310.66 mg.kg-1 for Fe. The results indicate that some of the vegetables and spices were contaminated with Cd and Pb and Ni. More than 80% of the examined samples had concentrations of these metals below statutory safe limits