Int. J. Renew. Energ & Environ Vol.2, pp 56-64(2016)

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1 Copyright 2016 National Centre for Energy and Environment, Energy Commission of Nigeria, University of Benin: ISSN Int. J. Renew. Energ & Environ Vol.2, pp 56-64(2016) CHARACTERIZATION OF POLYCYCLIC AROMATIC HYDROCARBONS IN SOIL AND EARTHWORM (APORRECTODEA LONGA) IN THE VICINITY OF TWO AUTOMOBILE WORKSHOPS IN BENIN CITY E. Biose *,S.O Dieta and A.A Enuneku Department of Environmental Management and Toxicology, Faculty of Life Sciences, University of Benin, Benin City *Corresponding author ABSTRACT This study was conducted to characterize polycyclic aromatic hydrocarbons (PAH) in soils and earthworms from selected auto mechanic workshops in Isihor (site A) and Agbor Park (Site B) Areas in Benin City. Samples were collected for three months. Quantification of the PAH components was accomplished using a gas chromatograph (HP 1100) with peak identification using a diode array detector (DAD). Of the sixteen PAHs analysed in soil, twelve compounds were found in site A while thirteen (13) PAHs compounds were found in site B. No significant difference was observed at (p>0.05) in the concentrations of the various PAH compounds analysed between the two sites in the soil. In earthworms, ten PAHs compounds were found in site A while nine were found in site B. Mean concentrations of Acenaphthene, Flourene, Phenanthrene, Anthracene, Fluoranthene, Pyrene, 1, 2-Benzothracene, Chysene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(a)pyrene, Dibenzo(a,h)anthracene, Benzo(g,h,i)perylene and Indeno(1,2,3-cd)pyrene in earthworm samples for site A were ±416.03, 23.07±39.95, 0.00±0.00, 17.71±30.67, 0.00±0.00, 0.00±0.00, 65.18±112.89, ±215.53, ±510.47, 0.00±0.00, ±25.80, ±204.13, ±349.28, ± µg/kg and 0.00±0.00, ±174.98, 60.02±103.95, 0.00±0.00, ±656.55, 0.00±0.00, 0.00±0.00, ±133.80, 0.00±0.00, ±199.02, ±431.44, ±938.23, ±225.32, 20.04±34.71µg/kg for site B respectively. Concentrations of Chysene in earthworms in Site B was significantly higher (p<0.05) than concentrations site A. Naphthalene, Acenaphthalene and Acenaphthene were not detected. Benzo(a)anthracene, chrysene, benzo(b)fluoranthrene and benzo(k)fluoranthrene have been implicated as carcinogens according to the US EPA. According to this study, 72% of the PAHs was detected in the soil while 28% was found in the earthworm. Currently, there are no standards/limits available for PAHs concentrations in soil and earthworm for comparison. It is evident from this study that the auto-mechanic sites are contaminated with PAHs. The risk of bioaccumulation of the PAHs along the food chain with subsequent exposure to man can be reduced by treating spent oil before discharge into the soil ecosystem. Keywords: PAHs, Spent Engine Oil, Soil, Health, Pollution, Benin City. 56

2 Introduction In Nigeria, as in many other countries, petroleum hydrocarbon contamination is widespread. Pollution arising from the disposal of used engine oil is one of the environmental problems in Nigeria and is more widespread than crude oil pollution (Odjegba and Sadiq, 2002). The prevalent mode of indiscriminate disposal of these spent engine oils in the environment calls for urgent attention. Contamination results from mishandling, deliberate disposal, spilling and leakage of petroleum products, such as gasoline, lubricating oils, diesel fuel, heating oils, used or spent engine oils. There are several other automobile workshops scattered all over the major cities in Nigeria from which used engine oils, lubricating oils and other solvents containing petroleum hydrocarbons are indiscriminately dumped or spilled on every available space by artisans in the business of auto-repairs. The local utilization of engine oil in Nigeria has increased in the recent times. This is due to the upsurge in the number of vehicles and other machines that makes use of these lubricants. These unguided practices have worsened the rate at which used engine oils spread and contaminate the soils and water in the environment. Studies in auto repair workshop sites have been carried out by many researchers (Ipeaiyeda and Dawodu, 2008). But most of them focused on the study of the implication of heavy metal contamination in soil by these used engine oils without recourse to the effects of other petroleum hydrocarbon pollutants such as the persistent and ubiquitous polycyclic aromatic hydrocarbons (PAH) present in used engine oils. These used oils and solvents form part of the most hazardous wastes are commonly generated in auto-repair shops around cities in Nigeria (Iwegbue, 2007). Waste oil is a mixture of different chemicals including petroleum hydrocarbons, chlorinated biphenyls, chlorodibenzofurans, additives, decomposition products and heavy metals that come from engine parts as they wear away (Wang et al., 2000; ASTDR, 1997). Used engine oil, also called spent lubricant or waste engine oil, is usually obtained after servicing and subsequently draining from automobile and generator engines (Sharifiet al., 2007). The exact composition of used oils depends on the origin, extent of use and degradation products that formed in the oil over time or during use. Ekundayoet al., (1989) have shown that noticeable changes in properties occur in soils polluted with petroleum hydrocarbons arising from used engine oils. Oil pollution of soil leads to build up of metals in soil and the eventual translocation in plant tissues (Vwiokoet al., 2006). Used engine oil easily migrates into the environment and eventually seeps into water bodies (Olugboji andogunwole, 2008). PAHs belong to a group of over 100 hazardous substances of organic pollutants consisting of two or more fused-benzene aromatic rings. Formation of Polycyclic Aromatic Hydrocarbons (PAH) is due to incomplete combustion of organic matter through the condensation of ethylenic radicals in the gas phase to form the larger polycyclic compounds (Lane, 1989). Those containing up to four benzene rings are known as light PAHs (l-pahs) and those containing more than four benzene rings are known as heavy PAHs (h-pahs). The h- PAHs are more stable and toxic than the l- PAHs (ATSDR, 1995). According to Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) list of hazardous substances, PAHs ranked 7th in 2005 in the biennial ranking of chemicals deemed to pose the greatest 57

3 possible risk to human health (Christopher, 2008). PAHs have low solubility in water and are highly lipophilic. In water or when adsorbed on particulate matter, PAHs can undergo photo decomposition in the presence of ultraviolet light from solar radiation. In the atmosphere, PAHs can react with ozone, nitrogen oxides and sulphur dioxide, to give diones, nitro- anddinitro-pahs, and sulphonic acids, respectively. PAHs have been demonstrated to be mutagenic and carcinogenic in humans (Phillip, 1999). Those PAHs that have not been found to be carcinogenic may, however, synergistically increase the carcinogenicity of other PAHs. Earthworms are terrestrial annelids with bilateral symmetry. They are important factors in the development of soil structure, organic matter breakdown and nutrient cycling. Generally, the activities of earthworm are considered to improve soil health and theoretically can translate to improved bioremediation. In spite of the numerous ways in which the activities of earthworm promotes soil health, relatively few research have been undertaken to study the effects of earthworm on petroleum hydrocarbons contamination removal from soil (Hickman and Reid, 2008). Schaefer and Juliane (2007) concluded that earthworms may trigger the degradation process and might therefore, be applied in the remediation of oil contaminated soil with moderate total petroleum hydrocarbon (TPH) concentrations. Ameh et al. (2011) reported the survival of earthworms (Eudriluseugeniae) in used engine oil from automobiles contaminated soil. They reported that used engine oil concentration level tolerable to earthworms was dependent on the source of the used engine oil. The aim of the study is to determine and characterize the concentrations of Polyaromatic hydrocarbon in soil and earthworm from two selected auto-mechanic workshops from Isihor and Agbor Park Area in Benin City. Materials and Methods Collection of Samples This study was carried out at two auto mechanic workshops in Benin City. Soil and earth worm samples were collected from two auto-mechanic workshops around Isihor and Agbor park area in Benin City. The soil samples were collected in clean polyethene bags for soil analysis while the earthworm samples were taken in clean plates for laboratory analysis. PAH Analysis PAH extraction in soil and earthworm was carried out using the US EPA 3540 C and 3630 C method. PAH was extracted from the soil and earthworm with 100ml methylenechloride for 24 hours. The extract was reduced to 2 ml and dissolved in cyclohexane to 5ml volume. The resulting extract was purified on a silica gel column. PAHs were eluted from the silica gel column with 25 ml of methylene/pentane mixture (2:3), reduced till dry and dissolved for analysis in acetonitrile. The acetonitrile extract was analyzed by gas chromatography (HP1100) with peak identification using a diode array detector (DAD). Statistical analysis Values have been expressed as means ± SD. Data collected were subjected to Excel and SPSS using analysis of variance at p>0.05 and significant levels at p>

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5 Results and Discussion Table 1 shows the average mean summary of PAHs compounds concentration analysed in the soil. Table 1: Concentrations of PAHs analysed in the soil from sites A and B. Site A Site B COMPONENT ±SD ±SD Naphthalene 0.00± ±0.00 Acenaphthylene 0.00± ±0.00 Acenaphthene 0.00± ±0.00 Fluorene ± ± Phenanthrene ± ± Anthracene 0.00± ± Fluoranthene ± ± Pyrene ± ± ,2-Benzothracene ± ± Chysene ± ± Benzo(b)fluoranthene ± ± Benzo(k)fluoranthene 21.04± ± Benzo(a)pyrene ± ± Dibenzo(a,h)anthracene ± ± Benzo(g,h.i) perylene ± ± Indeno(1,2,3-cd)pyrene ± ± Total ± ± All the PAHs parameters were measured in µg/kg (p>0.05 No Significant Difference) Table 1 shows the sixteen (16) PAHs compounds that were analysed in the soil. Sixteen PAHs compounds was analysed in the soil. Twelve (12) PAH compounds were found in site A while thirteen (13) PAHs compounds were found in site B in the soil. These include Fluorene, Phenanthrene, Anthracene, Fluoranthene, Pyrene, 1,2-Benzothracene, Chysene, Benzo(b)fluoranthrene, enzo(k)fluoranthrene, Benzo(a)pyrene, Dibenzo(a,h)anthracene, Benzo(g,h.i) perylene, Indeno(1,2,3-cd)pyrene. Anthracene 60

6 Concentration (µg/kg) Int. J. Renew. Energ & Environ Vol.2, pp 56-64(2016) was absent in site A. PAHs such as Naphthalene, Acenaphthalene and Acenaphthene were not detected probably due to the high volatilization or dissolution which may have occurred during the process of extraction. The nature of activities going on in the two mechanic workshops recorded similar influence on the PAH concentrations in the soil. Hence no significant difference was observed at (p>0.05) in the concentrations of the various PAH compounds analysed between the two sites in the soil. Site A Site B PAHs Figure 1: PAHs concentrations analysed in the Earthworm. Figure 1 shows the sixteen (16) PAHs compounds that were analysed in the earthworms. Ten (10) PAHs compounds were found in site A while nine (9) compounds were found in site B. These include Acenaphthene, Fluorene, Phenanthrene, Anthracene, Fluoranthene, Pyrene, 1,2-Benzothracene, Chysene, Benzo(b)fluoranthrene, Benzo(k)fluoranthrene, Benzo(a)pyrene, Dibenzo(a,h)anthracene, Benzo(g,h.i) perylene, Indeno(1,2,3-cd)pyrene. Naphthalene, Acenaphthalene, Phenanthrene, Fluoranthene, Pyrene, Benzo(k)fluoranthrene were not detected in site A while Naphthalene, Acenaphthylene, Acenaphthalene, Anthracene, Pyrene, 1,2-Benzothracene and Benzo(b)fluoranthrene was not detected in site B.Unlike the observation recorded in concentrations of PAHs in the soil, Chysene showed a significant difference (p<0.05) among the two sites and high concentration of Chysene was observed in site B than site A. Other PAhs compounds analysed showed no significant difference(p>0.05) in occurrence. The results also showed that Fluoranthene, Chysene, Phenanthrene, benzo[b]fluoranthene, Dibenzo(a,h)anthracene, and Indeno(1,2,3- cd)pyrene constituted the largest group of compounds with high concentrations in the soil and earthworm samples respectively. This 61

7 result is consistent with Obini et al., (2007) who reported high Fluoranthene, Phenanthrene and Benzo[b]Fluoranthene in oil polluted sites in Abakaliki. In earthworm tissues analysed in this study, PAH compounds were accumulated. It is evident from the results that the soils collected from the auto-mechanic sites were contaminated with PAHs at varying concentrations. However the total PAH concentrations were high when compared with the maximum background limits of 15mg/kg and 50mg/kg in polluted soils set by Dutch and Polish/ Environment Ministries respectively, (Polish Environment Ministry, 2002). The high values recorded in this study should be taken seriously as the high values relate to indiscriminate and improper use of the waste crude oil products. However, there is no level above or below which carcinogenic effects of PAH does not occur. The sixteen (16) PAH compounds detected fall within the category of PAHs with the highest health risk especially at prolonged exposure (ATSDR, 1999). Four out of the sixteen (16) PAHs namely benzo(a)anthracene, chrysene, benzo(b)fluoranthrene and benzo(k)fluoranthrene have been implicated as carcinogens according to the California Environmental Protection Agency, (1994). The health effects of PAHs have been reviewed extensively. These effects depend mainly on the extent of exposure, dose, innate toxicity and exposure routes. Other predisposing factors include pre-existing health status and age. There is risk of harm in both short and long term exposure especially among the artisans in the mechanic workshop. PAHs are ubiquitous in the urban and rural environment. As a result, it is very common to detect levels of PAHs in soils even at low levels and its toxicity consideration is of utmost importance. PAHs pose a major threat in terms of its carcinogenic effects. Some studies have shown that heavy PAHs can induce dioxin-like activity and weakened estrogenic responses (Villeneuve et al., 2002). The chemistry and toxicity of PAHs are best understood using benzo[a]pyrene which has been extensively studied with a well established chemistry of its carcinogenic effects (Lee and Shim, 2007). Its metabolites were said to be mutagenic and highly carcinogenic, and is listed as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). The compound is one of the benzopyrenes, formed by a benzene ring fused to pyrene, and is the result of incomplete combustion at temperatures between 300 C and 600 C (Aygün and Kabadayi, 2005). The PAHs compounds were abundant in the soils than in the earthworms. According to this study, 72% was found in the soil while 28% was found in the earthworm. Conclusion It is evident from this study that the automechanic sites were heavily contaminated with PAHs arising from indiscriminate disposal of spent crankcase engine oils and the earthworm associated with the contaminated soils showed bioaccumulation of the PAHs. The risk of bioaccumulation of the PAHs along the food chain with subsequent exposure to man can be reduced by treating spent oil before discharge into the soil ecosystem. 62

8 References ATSDR (Agency for Toxic Substances and Disease Registry) (1997). Toxicology profile for used mineral based crankcase oil. Department of Health and Human Services. Pp: 1-3. ATSDR, (1995). Chemical and physical information: in Toxicological Profile for ambient air. Environmental Health Perspectives110(3): ATSDR (1999). Toxicological profile for ethylbenzene. Agency for Toxic Substances and Disease Registry, Public Health Service, U.S. Department of Health and Human Services, Atlanta, G.A. USA Aygün, S. F. and Kabadayi, F.(2005). Determination of benzo[a]pyrene in charcoal grilled meat samples by HPLC with fluorescence detection. International Journal of Food Sciences andnutrition 56(8): Christopher, M. (2008). Polycyclic Aromatic Hydrocarbons (PAHs) in Urban Soil: A Florida Risk Assessment Perspective. International Journal of Soil, Sediment and Water1(2): Ekundayo, J. A. and Aisueni, M. O. (1989). The Effects of drilling fluids in some waste and burrow pits in western operational areas of Shell Petroleum Development Company of Nigeria Limited on the soil and water quality of the areas. Environmental Consultancy Service Group, Consultancy Services Unit, University of Benin, Benin City, Nigeria. Pp: 2-9. Ipeaiyeda, A. R. and Dawodu, M. (2008). Heavy metals contamination of topsoil and dispersion in the vicinities of reclaimed autorepair workshops in Iwo, Nigeria. Bulletin of Chemical Society of Ethiopia22(3): Iwegbue, C. M. (2007). Metal fractionation in soil profiles at automobile Mechanic Waste Dumps around Port Harcourt. Waste Management Resource25(6): Lane, D. A. (1989). The fate of polycyclic aromatic compounds in the atmosphere and during sampling. In: Chemical analysis of polycyclic aromatic compounds. T.Vo-Dinh (Ed.), J.Wiley & Sons. USA pp Lee, B. M. and Shim, G. A. (2007). Dietary exposure estimation of benzo[a]pyrene and cancer risk assessment. Journal of Toxicology and Environmental Health Part A. 70(15-16): Obini., C. O. and Okafor; J. N. and AFIUKWA, J. N. (2013). Determination of levels of polycyclic aromatic hydrocarbons in soil contaminated with spent motor Engine oil in Abakaliki Auto- Mechanic Village. Applied Science of Environmental Management 17 (2):

9 Odjegba, V. J. and Sadiq, A. O. (2002). Effects of spent engine oil on the growth parameters, chlorophyll and protein levels of Amaranthushybridus L. The Environmentalist22: Olugboji, O. A. and Ogunwole, O. A. (2008). Use of spent engine oil. Journal of Technology12(1): Phillips, D. H., (1999). Polycyclic aromatic hydrocarbons in the diet. Mutation Research443(1-2): Polish Environment Ministry (2002). Quality standards for soils due to a particular PAH content. DZ.U.No.165. p. 135 Sharifi, M., Sadeghi, Y. and Akbarpour, M. (2007). Germination and growth of six plant species on contaminated soil with spent oil. International Journal of Environmental Science and Technology4(4): Villeneuve, D. L., Khim, J. S., Kannan, K. and Giesy, P. (2002). Relative potencies of individual polycyclic aromatic hydrocarbons to induce dioxinlike and estrogenic responses in three cell lines. Environmental Toxicology 17(2): Vwioko, D. E., Anoliefo, G. O., Fashemi, S. D. (2006). Metals concentration in plant tissues of Ricinuscommunis L. (Castor Oil) grown in soil contaminated with spent lubricating oil. Journalof Applied Science and EnvironmentalManagement10: Wang, J., Jia, C. R., Wong, C. K., Wong, P. K. (2000). Characterization of polycyclic aromatic hydrocarbon created in lubricating oils. Water, Air Soil Pollution120: California Environmental Protection Agency (CalEPA). (1994). Memorandum, to Cal/EPA Departments, Boards, and Offices from Standards and Criteria Work Group, Office of Environmental Health Hazard Assessment. Subject: California Cancer Potency Factors. In: A methodology for using background PAHS to support remediation decisions (2000). ENVIRON Corporation Emeryville, California. p.32 Ameh AO, Mohammed-Dabo IA, Ibrahim S, Ameh JB, Azienge CD, Yahuza T (2011). Earthworm survival in used engine oil contaminated soil spiked with manure. Int. J. Biol. Chem. Sci. 5(3): Hickman ZA, Reid BJ (2008). Earthworm assisted bioremediation of organic contaminants. Environ. Int. 34: Schaefer M, Juliane F (2007). The influence of earthworms and organic additives on the biodegradation of oil contaminated soil. Appl. Soil Ecol. 36: Schaefer M, Peterson SO, Filser J (2005) Effects of Lumbricus chlorotica and Eisenia fetida on microbial community dynamics in oilcontaminated soil. Soil Biol. Biochem. 37: