ABSTRACT
Lubricating oil usually contains chemical additives including amines, phenols, benzenes,
calcium, zinc, barium, magnesium, phosphorus, sulphur and lead. This study was done to
assess the changes in physicochemical and heavy metal properties of soil treated with spent
engine oil and poultry manure after 12 weeks of growing Phyllanthus urinaria. It was done
in the screen house of the Department of Plant Science and Biotechnology, Michael Okpara
university of Agriculture, Umudike (MOUAU). Soil samples at the depth of 0 – 15 cm, spent
engine oil and the manure were sourced from the vicinity of MOUAU. Completely
randomized designed (CRD) having only one factor (Spent engine oil) at five different levels
(Negative control, Positive control, 1%, 3% and 5%). Samples were tested for heavy metal
before and after treatment, physical and chemical properties. Data collected was subjected
to descriptive statistics to obtain the means and standard deviations. T-test analysis was used
to compare the difference in the heavy metal properties of soil and spent engine oil. Means
of laboratory analysis were subjected to analysis of variance (ANOVA). Statistically
significant means at 5% probability were separated using Duncan Multiple Range Test
(DMRT) all the test was done using statistical package for social sciences (SPSS) version 26.
From the result, Significant variation (P<0.005) was observed between heavy metal soil and
spent engine oil samples. The samples were largely acidic at a range of 4.55±0.07 to
6.91±0.01. The percentage sand level ranged from 55.20±0.00% to 75.81±0.01%, the silt was
at a range of 11.41±0.01% of 3% to 22.00±0.00%, while clay was observed to be at a range
of 6.81±0.01% to 23.00±1.41%. The highest phosphorus and Nitrogen level were observed
to be 128.55±6.68 mg/kg and 0.29±0.01 % respectively. Effect of treatment was significant
(P≤0.05) to soil nitrogen levels. Organic Matter (OM) ranges from 2.82±0.01 % of positive
control sample to 6.10±0.01 % of 1 % sample. Treatment effect was significant (P<0.05) on
physical and chemical properties of soil. The physical, chemical and heavy metal were
significant (P≤0.05) to changes in their concentrations. Higher heavy metal was observed to
be in spent engine oil than those of the farm soil. Confirming spent engine oil as soil
contaminant. Higher OC, OM was seen in the soil of samples treated with spent engine oil.
No traces of Pb and Zn was seen in the plant and soil used after 12 weeks of observation.
KEYWORDS:Heavy Metal, Manure Physicochemical, Soil, Waste Engine Oil
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