CONCENTRATION OF HEAVY METALS IN PADDY SOILS AND ITS ACCUMULATION IN RICE (Oriza Sativa) GRAINS IN GASHUA, BADE LOCAL GOVERNMENT AREA, YOBE STATE, NIGERIA

Abstract

Heavy metals are large group of metals having specific density greater than 5 g/cm3 and are known to exist naturally in the earth crust. The study determined the concentration of heavy metals in paddy soil and rice grains in Gashua, Bade local government area, Yobe state. Three sampling stations were selected, Station A (Jabulle), B (Bayan Gada) and C (layin Kwata). The quantities of heavy metals (Pb, Cr, Cd, Cu, As, and Ni) were determined in both the soil and paddy rice grains.  The mean values of metals found in soil (mg/kg) in station A were as follows: Lead (3.13±0.137), Chromium (2.82±0.65), Cadmium (1.37±0.14), Copper (5.86±0.63), Arsenic (1.33±0.14) and Nickel (2.93±0.32), while station B: Lead (6.10±1.027), Chromium (2.94±0.17), Cadmium (2.67±0.49), Copper (9.38±1.34), Arsenic (2.35±0.10) and Nickel (4.69±0.67) and station C: Lead (1.85± 0.41), Chromium (2.38±0.14), Cadmium (1.49±0.44), Copper (4.58±0.37), Arsenic (1.04±0.08) and Nickel (2.29±0.18). Heavy metals were detected in the order Cu > Pb > Ni > Cr > Cd > As and as > Cd > Cr > Ni > Pb > Cu > in the soil and rice samples, respectively. The physico-chemical value obtained in station A were pH (6.7 ± 0.21), Electrical Conductivity (504±430.62), Organic Carbon (3.4±0.66) and Moisture (11.10±1.08), while for station B: pH (6.9±0.31), Electrical Conductivity (545±97.04), Organic Carbon (2.34±1.29) and Moisture (11.49±1.66) and station C: pH (6.4±0.2), Electrical Conductivity (824±27.22), Organic Carbon (2.43±0.37) and Moisture (8.94±1.30).