Remedial ability of maize(Zea-Mays)on lead contamination under potted condition and non-potted field soil condition

This study presents the remedial ability of maize on lead(Pb)contaminated soil.Soil samples were collected randomly from the site and subjected to physico-chemical tests before experimen-tation.The samples were contaminated artificially at six different concentration levels of lead nitrate(Pb(NO_(3))_(2)).Experimental design was 4-factorial combination(6×6×2×1).The study duration was 10 weeks,and during this period,Pb contents of the soil were analyzed in intervals of two weeks.Analyzed physico-chemical properties of the soil showed that the soil was loamy with pH 6.82,electrical conductivity 1.62 dS/m and adequate macro nutrient elements.The av-erage percentage removal of Pb from the soil was 2.25%and 3.67%for potted and non-potted experiments,respectively.Similarly,the average percentage of Pb in the roots was 1.10%and 1.68%for potted and non-potted experiments,respectively.The result of this study indicated that extraction of Pb by the plant system increased with the increase of lead concentration in the soil as well as in the extent of vegetation attained by the crop.It also clearly showed that the non-potted experiments demonstrated greater influence on removal of Pb from the soil system than the potted experiments.

Evaluation of rice husk ash and Portland cement reinforced clay for use as road subgrade using the CBR test

The amount of rice husk waste generated in Nigeria is posing serious threat to the environment and the ecosystem.Utilizing these wastes for productive purposes has been of interest to government and researchers.This study evaluated rice hush ash(RHA)reinforced clay for use as road subgrade,using the California Bearing Ratio(CBR)as prescribed in ASTM D1883.The clay was mixed with RHA/Portland cement in the ratios of 0%(control),2.5%,5%,7.5%and 10%.Results showed that the physical properties of the soil in its natural form did not meet the FMW&H guideline specification for subgrade road;thus there was a need to stabilize the soil.As the percentage of RHA increased,the strength of the soil increased,with the maximum strength observed at 5%RHA,beyond which there was decrease in the load bearing capacity of the soil.Optimal CBR ratio of 9.35%was obtained at 5%RHA,5%Portland cement and 90%clay soil.Comparing this result with the soil at natural state(CBR=1.55%),it shows that RHA is a good improvement agent for the soil.This research can be beneficial to highway road construction in areas with similar soil conditions.