Heavy Metals Status of Soil and Their Uptake by Fluted Pumpkin (telfairia Occidentalis Hook F) Cultivated Along Ikpoba River Bank, Benin City

This study was carried out to assess the status of heavy metals in the soil and fluted pumpkin cultivated on the bank of Ikpoba River at Benin City. The sample area was 9000 m2. Soil samples were collected at 0-30 cm and 30-60 cm depths at 30 locations giving a total of 60 samples. The plants were also sampled along with the sampling of the soils giving a total of 30 plant samples. Similar numbers of soil samples along with 30 plant samples were collected at University of Benin demonstration farm, a distance of about 10 km away from the river bank to represent the control. Samplings were carried out during dry and rainy seasons. Result showed that the Fe, Cu, Mn and Cr content of soil increased significantly with increasing depth in both the control and river bank during dry and rainy seasons. The content of Fe, Cu, Mn and Cr in river bank soil was however, higher during dry season compared to that of control and rainy season. The Cd component of the river bank soil was minimal and fairly stable with increasing soil depth during dry and rainy seasons. The Cd was however not detected in the control soils. The Pb content of the river bank soil decreased with increasing depth during dry and rainy seasons while in the control sites, the Pb was below detectable level during the dry and rainy seasons. Significantly, higher contents of Fe, Cu, Mn, Cr, Cd and Pb and their uptake by fluted pumpkin at river bank were recorded compared to uptake by plants at the control sites. The sand correlated negatively with Cr, Cd and Pb uptake by the plant while the clay and soil pH correlated negatively with the uptake of Fe, Cu, Mn, Cr, Cd and Pb. The silt and organic matter however correlated positively with the uptake of Fe, Cu, Mn, Cr, Cd and Pb by the plant. The transfer Factor was higher in Cu compared to other metals.