Assessment of Physicochemical Parameters of Soils Contaminated with Petroleum from Eleme Port Harcourt, Nigeria
Abstract
The study was conducted to examine the physicochemical parameters of soils contaminated with petroleum using nonpetroleum contaminated soil as control. Six petroleum contaminated soil samples from Eleme, Port Harcourt and one non petroleum contaminated soil sample from Awka were analyzed for pH, texture, moisture content, bulk density, total organic carbon, total organic nitrogen, total organic matter and total petroleum hydrocarbon. Some pH of the soil samples were acidic while others were alkaline and ranged from 5.26-7.84. The textural class of the petroleum contaminated soils (A-F) were silty clay loam while that of the non petroleum contaminated soil (G) was sandy loam implying that samples A-F are somewhat clayey and sample G almost sandy. Total moisture content of petroleum contaminated soils and their water holding capacity were higher than that of the control and fell in the ranges 0.50-40.56% and 13-29% respectively. Total organic carbon (TOC) and Total organic matter (TOM) of petroleum contaminated soils were higher than that of the non petroleum contaminated soil and were within the ranges 7.29-15.09% and 12.57-26.02% respectively. Total organic nitrogen result follow the same pattern with the non petroleum contaminated soil having the least value. The range was 0.365-0.755%. Bulk density results were within the range of 0.80-1.42g/cm3 . The uncontaminated soil (G) had less amount of organic matter in it as a result, the bulk density was the highest (Olaitan and Lombin, 1984). The total petroleum hydrocarbon (TPH) content ranged from 107.5305-626.4060 mg/kg with that of the non petroleum contaminated soil being the least. The results indicated that petroleum contamination affected the physicochemical properties of the soils analyzed. Regular soil assessment is recommended so as to avert any ugly incidence which may occur.
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Introduction
Contamination of the environment by petroleum products from variety of sources represents one of the most frequent contaminations {Mracnova et al.,1999). This is due to the growing demand and supply of fuel oil and new chemicals by the industrialized society of the twenty-first century (Jaffe,1991). High concentration levels of hydrocarbons present in contaminated sites can pose a health risk to humans, plants and animal lives as they are carcinogenic, mutagenic and toxic (Ribes et al., 2003, Freitag et al., 1985 and DEC,1992).
Oil contamination can also affect soil physical and chemical properties (Wang et al., 2013). Soil temperature, total organic carbon, pH, microbial community, available phosphorus and other soil chemical properties are affected (Aislabie et al., 2004, Townsend et al., 2003, Ekundayo and Obuekwe, 2000, Hu et al,. 2006), Oil causes anaerobic environment in the soil by smothering soil particles and blocking air diffusion in the soil pores. In addition, crude oil contaminated soils are hydrophobic compared with pristine sites (Quyum et al., 2002).
An assessment of the physicochemical parameters of petroleum contaminated soils from Eleme, Port Harcourt was embarked upon to monitor the levels of contaminants which can accumulate toxic proportions. The oil finds its way to soil through leakages from pipelines, underground and surface fuel storage tanks, indiscriminate spills, and careless disposal of wastes (Okop, and Ekpo, 2012). Despite improvements to the technical conditions of sites involved in the production, storage and distribution of liquid fuels, the threat to the environment posed by petroleum substance is still very real (PIEP,1995).
Conclusion
Higher levels of organic nitrogen are observed in samples A-F (petroleum contaminated soils) than in sample G (control). This again is due to increased level of decayed organic matter and contamination by petroleum in samples A-F. Nitrogen compounds detected in petroleum include polycyclic aromatic amines, carbazole, benzocarbazole, heterocyclic aromatics, triaromatic azaarenes, nitrogen heterocycles as well as diaromatic nitrogen bases (Thomas and Ringen, 1985).