NUTRIENT CONTENTS AND METAL ACCUMULATION IN VIGNA UNGUICULATA L (BEAN) SEEDLINGS IN PETROLEUM CONTAMINATED SOILS

Abstract

The study examined some nutrient content and metals accumulated by bean seedlings in petroleum-contaminated soils. Bean seeds were planted in soil contaminated with 2%, 5% and 10% v/w petroleum for 21 days. After 7, 14 and 21 days post germination, nutrient contents analyzed were greatly reduced in the contaminated soil and seedlings in percentage contamination manner when compared with control. The mean values of 0.84mg/kg and 5.00mg/kg Pb, 46.12mg/kg and 50.00mg/kg Zn, 165.18mg/kg and 300.95mg/kg Fe, respectively, were obtained in the petroleum contaminated soil before planting. The results indicates that metals accumulated by bean seedlings were below intervention values. However continuous uptake of these non-biodegradable metals may accumulate to toxic levels, posing health risks in the food chain. After 21 days post-harvest of bean seedlings, 77% Zn, 64% Fe, 29% Cu and 10% Pb was recorded in petroleum contaminated soil while 75% Zn, 86% Fe, 46% Cu and 3% Pb was found in the petroleum spill soil (Ubeji Community). The study revealed that bean seedlings accumulated some metals and its nutrient contents were reduced in petroleum contaminated soils. The results suggest that metal accumulation and reduced nutrient contents was responsible for inhibition of germination and growth of the bean seedlings. It is necessary to minimize the detrimental effects of petroleum toxicity in bean seedlings by providing measures to prevent spill and rapidly decontaminating the soil if/when petroleum spill occurs. Keywords: Bean, Metal Accumulation, Nutrient Content, Petroleum-Contaminated Soil