Determination of the Concentration Levels of Total Petroleum Hydrocarbons (TPH) in Soils Found in Automobile Shops
Chapter One
OBJECTIVES OF STUDY
This study aims to determine the concentration levels of total petroleum hydrocarbons (TPH) in soils found in automobile shops (keke, car, bikes, and truck workshops).
Objectives:
- The objective of this work is to ascertain the level of TPHin analyzed samples.
- To determine the concentration of TPHin the selected locations ofWarri Metropolis (Warri, Effurun, Ughelli and Udu).
- To evaluate the impact of TPH on soil consequently, the risk posed to public health as a result of the identified pollution.
CHAPTER TWO
LITERATURE REVIEW
TOTAL PETROLEUM HYDROCARBONS
Petroleum can be defined as any hydrocarbon mixture of natural gas, condensate, or crude oil. Crude oil is the main source material for nearly all petroleum products. This material is distilled into a series of fractions to make different petroleum products; each characterized by the temperature and pressure of distillation. Thus, the type of petroleum product is a direct result of the boiling point of the crude used in the product. For instance, lighter -actions of crude with lower distillation temperatures are used for diesel, jet fuels, and light heating oil’s. Heavy fuel oils are made up of the residue from the distillation process and are composed of the heaviest fractions with the highest distillation temperatures. The temperature of distillation also functionally defines the volatility of the fuel, with gasoline’s being highly volatile and residual fuels only slightly volatile.
Petroleum products includinggasoline, diesel or lubricants can be released to the environmentthrough accidents, managed spills, or as unintended by-products of industrial, commercial or private actions; causing local and diffusepollution to the environment (Park and Park, 2011). Environmentalcontamination is widespread due to the great number of facilitiesand processes, affecting human health, water resources, ecosystemsand other receptors (Burgess, 2013). Petroleum mixtures canbe affected by air, water and organisms, thereby changing thelocation and their composition in soil,water or air.
Petroleum hydrocarbons are compounds of petroleum that consist almost entirely of the elements of hydrogen and carbon. They are not distinct entities, but rather, represent a continuum over a broad range, by molecular weight, of individual hydrocarbons. Gasoline, diesel fuel, and related products contain hundreds and sometimes thousands of different petroleum hydrocarbons. In addition to the process of distillation, the makeup of individual petroleum products is also dependent on refinery processes performed to give the product desired characteristics. For instance, gasolinesare created by blending different products of distillation with various additives in order tocreate a product that meets engine performance criteria. The significance of theproduction process is that some petroleum products may have little resemblance to the initial distillate produced during the initial processing of crude.
Petroleum hydrocarbons can be divided into four major structural groups. The first group is defined by chemists as alkanes (and by geologists as paraffin’s). These hydrocarbons are saturated; which means that each carbon atom forms four single bonds with the hydrogen and other carbon atoms which make up each compound. These hydrocarbons are also aliphatic; which means that the carbon atoms are joined by straight or branched chain arrangements. This group usually dominates the gasoline fractions of crude oil. Examples of compounds in this group are hexane, heptane, octane, and decane. The second group is composed of cycloalkanes (or napthalenes). Hydrocarbons in this group are saturated hydrocarbons which are characterized by their ring type structure. Methlycyclo-pentane (C6-H 12) and ethylcyclo-p-hexane (C8H 16) are examples of hydrocarbons in this group. The third group is composed of the alkenes (or olefins). Hydrocarbons in this group are unsaturated, which means they contain at least two carbon atoms joined by more than one covalent bond, and aliphatic. The fourth group includes arenes (or aromatics). All compounds in this group contain at least one benzene ring. BTEX compounds fall into this group. Compounds in this group that contain three or more closed rings are termed “polynuclear” or “polycyclic” aromatic hydrocarbons (PAHs).
Hartley and Ohanian provide one example of composition of unleaded gasoline. In their analysis, they found the following composition of hydrocarbons: 56% alkanes, 34% aromatics, 10% alkenes, and less than one percent PAHs. The BTEX compounds of petroleum are of concern because of their toxicity.
ORIGINS OF HYDROCARBONS IN SOIL
Hydrocarbon species can enter the soil environment from a number of sources. The origin of the contaminants has a significant bearing upon the species present and hence the analytical methodology to be used. Unlike other chemicals (notably pesticides) hydrocarbons were generally not applied to soils for a purpose and thus hydrocarbon contamination results almost entirely from misadventure. The source that is probably most familiar to persons involved in the study of contaminated sites is leakage from underground storage tanks. This is particularly important at the site of former petrol stations and the hydrocarbons involved are generally in the gasoline range. Other major sources include spillage during refueling and lubrication (notably in places such as railway yards), the hydrocarbons here being within the diesel and heavy oil range. Places in which transfer and handling of crude oils takes place (such as tanker terminals and oil refineries) are also potential places of contamination, the oil being largely of the heavier
hydrocarbon type. Shale oil retorting plants provide another source of hydrocarbon contamination as do coal gasworks sites, particularly those at which “benzole recovery” was practiced (Barash and. Although the majority of hydrocarbons in the soil environment are anthropogenic in nature, there are some natural sources of these materials. Included in this category are seeps from oil deposits (such as shale oil mineralization) and degradation of organic matter. There is also a body of evidence to show that certain organisms, notably higher plants are capable of synthesizing hydrocarbons and these too could find their way into the soil environment. These latter sources are however fairly minor and are unlikely to result in significant soil contamination.
CHAPTER Three
MATERIALS AND METHODS
SAMPLE STUDY AREA
The study area includes a host of locations situated in Warri metropolis (Warri/Sapele road,Petroleum Training Institute (PTI)road, Otokutu, Okuokoko, Okorikperhe and Agbarho).
LOCATION
The study area comprises of a pair of 4 locations making up a total of 8 locations of which two samples are to be collected from each. These locations include; 2 locations from PTI road, 2 locations from Agbarho, and Okuokoko, Okorikperhe, Warri/Sapele and Otokutu roads each comprising of a pair of locations.
CHAPTER FOUR
RESULTS
Table 2: Results of Total Petroleum Hydrocarbons (TPH) (mg/kg)
CHAPTER FIVE
DISCUSSION
TheTotal Petroleum Hydrocarbon(TPH) concentration of samples(mg/kg) from the study area of Warri Metropolis were asfollows;157150.24for (Agbarhokeke 10m away) and 48619.76for (Agbarhokeke main workshop), 37763.6for (Okuokoko truck main workshop) and 13114.8for (Okuokoko truck 10m away), 15745.0for (Warri/Sapelekeke road main workshop) and 1766.67for (Warri/Sapelekeke 10m away), 14380.8for (Okorikperhe truck main workshop) and 249.92for (Okorikperhe truck 10m away) and 17041.6for (PTI road car 2 main workshop) and 3239.38for (PTI road car 2 10m away), 1097.15for (Agbarho bike main workshop) and 2317.68for (Agbarho bike 10m away), 1366.48for (Otokutu bike main workshop) and1127.99for (Otokutu bike 10m away), 1198.90for (PTI car 1 main workshop) and 1077.36for (PTI car 1 10m away),And were also higher than DPR.(2002) and NSW. (2009) recommended maximum permissible limit of 1000mg/kg indicating high level contamination of soil samples from study site. Alinnor and Nwachukwu,(2013) reported that soil samples in Rivers State, Nigeria were contaminated with TPH concentrations of 1534.7, 1438.0 and 1651.0 mg/kg at depths respectively, which are almost in range with some of the results and also lower than other values obtained in this study. According to Iturbeet al. (2004), the soil of coastal Mexican refinery was heavily contaminated with hydrocarbons with detectable TPHconcentration of 130000 mg/kg. This value was higher than those recorded at soils from the study site in this work.
CONCLUSION
In this study, the rate of contamination in the environment of interest is far exceeding the allowable limit of 1000mg/kg (DPR 2002). Hence it could be concluded that the area of sampling is highly contaminated which could be as a result of uncontrolled disposal of spent oil by mechanics in the area of interest. This could affect the neighboring water body and further infiltrate into the ground water causing ground water pollution which could lead to an epidemic if not well taken care of. TPH compounds are generally carcinogenic, Genotoxic, teratogenic and immunotoxic in nature
RECOMMENDATION
The composition of petroleum and petroleum products is extremely complex. This complexity makes it difficult to determine environmental impacts at petroleum release sites using traditional EPA methods. It should be very clear that a TPH measurement cannot be used to evaluate risk. TPH methods measure a subset of the sum of a complex mixture of compounds varying greatly in potential toxic properties. Target analyte methods measure only a few of the many compounds in petroleum. Clearly, different analytical methods used for the determination of the environmental impact of petroleum and petroleum products will provide very different information.
- The laboratory experimental work should be confirmed by additional testing such as duplication, finer range of parameter variation, etc.
- Bacteria growth in-situ should be studied to validate the laboratory findings.
- The influence of the type of electron acceptor (oxygen, hydrogen peroxide, etc.)should be evaluated.
- Bioremediation of affected sites could be done.
REFERENCES
- Alinnor I. J. and Nwachukwu M. A., (2013).Determination of total petroleum hydrocarbon in Soil and groundwater samples in some communities in Rivers State, Nigeria. J. Environmental Chemical and Ecotoxicology. 5(11):292-297.
- ATSDR (Agency for Toxic Substances and Disease Registry).,(1999).Toxicological Profile for Total Petroleum Hydrocarbons (TPH). U.S.Department of Health and Human Services, Public Health Service, Atlanta, Georgia, USA.
- Burgess, L.C., 2013. Organic pollutants in soil. In: Brevik, E.C., Burgess, L.C. (Eds.), Soils and Human Health. CRC Press, Boca Raton, Florida, USA, pp. 83e106.
- Cortes J.E, Suspes A, Roa S, Gonzalez C, Castro H. E (2012).Total petroleum hydrocarbon by Gas Chromatography in Colombia waters and soil.American Journal of Environmental Science. 8(4):396-402.
- DPR.(1991). Environmental guidelines and standards for the petroleum industry in Nigeria.
- Department of Petroleum Resources, Ministry of petroleum and mineral resources,Lagos, Nigeria.
- Environmental Agency. (2003). Principles for evaluating the human health RisksFrom Petroleum hydrocarbons in Soils. A consultation paper.R & D technical reportP5-080/TRI.P 10. Available at: www.environment-agency.gov.uk. Accessed11/07/2012.
- Gruiz, K. and Kriston, E.(1995).In situ bioremediation of hydrocarbon in soil.Journal ofSoil Contamination .4(2): 163- 173.
