1 POLYCYCLIC AROMATIC HYDROCARBONS in SOILS WITHIN the COALITE PLANT in BOLSOVER, NORTH DERBYSHIRE Ivwurie W., Emelife S.C
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Journal of Engineering and Applied Scientific Research Volume 8, ISSN: 2384-6569 Number 1, 2016 POLYCYCLIC AROMATIC HYDROCARBONS IN SOILS WITHIN THE COALITE PLANT IN BOLSOVER, NORTH DERBYSHIRE Ivwurie W., Emelife S.C., Sun C. and Snape C. Department of Chemistry, Federal University of Petroleum Resources, Effurun Email: [email protected] Abstract: Five soil samples collected at varying distances from the Coalite plant in Bolsover, North Derbyshire were analyzed for Polycyclic Aromatic Hydrocarbons using GC-MS. The concentrations of the PAHs ranged from 0.03-2mgg-1 with a mean concentration of 4.50mgg- 1 1.51mgg-1. The PAH diagnostic ratio (Flu / (Flu + Py)) showed a predominant contribution from liquid fossil fuel combustion and coal combustion with a least contribution from petroleum source. Keywords: Polycyclic Aromatic Hydrocarbons, Soils, Coal Combustion Received for Publication on 16 March 2016 and Accepted in Final Form 23 March 2016 Hydrocarbons are a widespread class of INTRODUCTION contaminants in recent environments due The conversion of coal and petroleum to to the multiplicity of their sources [10, 11]. utilizable products like gasoline, diesel and These hydrocarbons can be synthesized by petrochemicals; which are further living organisms (biogenic origin), processed to give secondary products like produced during the degradation of the plastics, dyes, drugs or served as direct organic matter (diagenic origin), formed source of energy to plants and automobiles during incomplete organic matter has brought about the emission of toxic combustion (pyrolytic origin) and inorganic species such as NOx, SOx, CO, introduced in the modern environment CO2 as well as large quantities of organic effluents into the environment. Some of these materials are not readily biodegradable and can therefore find their via natural and anthrogenic release of fossil way in food chains, through diverse routes, fuel combustibles (petrogenic origin) [10]. endangering the life of living organisms and the ecosystem at large [3,7,12]. 1 Polycyclic Aromatic Hydrocarbons in Soils within the Coalite Plant in Bolsover, North Derbyshire Amongst the organic species that find their a. 350 g of soil, 20-30 metres from the way into the environment as a result of plant designated as Bolsv.1 diverse industrial and domestic operations b. 370 g of soil, 50 metres from the are the polycyclic aromatic hydrocarbons plant designated as Bolsv.2 (PAHs). These originate from the c. 300 g of soil, 500 metres from the incomplete combustion of organic materials plant designated as Bolsv.3 or directly from fossils fuels, as well as from d. 400 g of M1 motorway roadside direct biogenic precursors [1]. The fate of dust designated as Bolsv.4 PAHs in the environment has drawn e. 450 g of farm field soil designated attention from various researchers. This is as Bolsv.5 because PAHs come from different sources, The different soils were dried at a coupled with the diverse pathways that temperature of 105°C for 3 to 4 hours and they follow when they are discharged into then ground to pass through a 60-mesh the environment. It is therefore the sieve. objectives of this work to determine the concentrations and the distributions of the MATERIALS AND METHOD PAHs in some selected soils at varying Sample Extraction and Purification distances from the Coalite plant in Bolsover The samples were extracted by soxhlet and their possible sources. extraction and refluxing techniques using redistilled dichloromethane (DCM) and DESCRIPTION OF STUDY AREA AND SOIL dichloromethane- methanol (93:7) SAMPLING mixture. The weight of each sample The studied areas are situated around the extracted was altered to obtain sufficient Coalite low temperature carbonization amounts of PAHs analysis. 100 g of soil to plant in Bolsover. Bolsover is a small town 250 ml of solvent mixture was used for near Chesterfield, Derbyshire in England. It each extraction. When refluxing and is 233 km from London and 42 km from soxhlet extraction were completed, the Nottingham. The area is known for Coal slurries were filtered to obtain the extract mining. A schematic sketch showing the solution. The extract of each sample was sample collection points is given in Figure concentrated using rotary evaporator at 1. 30oC for DCM solutions and 45°C for The following 5 samples were collected DCM/methanol mixtures. The extract was according to their distance from the Coalite concentrated and dried using a stream of plant: N2. Open column chromatographic separation was then carried out on each 2 Journal of Engineering and Applied Scientific Research Volume 8, Number 1, 2016 extract obtained and the neutral aromatics containing the PAHs together with the RESULTS AND DISCUSSIONS aliphatics were kept for analysis. PAH Concentration and Distribution PAH Analysis The individual PAH concentrations of the The extract were analyzed for Naphthalene, soils ranged from 0.03 –2 mgg-1 dry weight 2,4-dimethylnaphthalene, 1,2,4- (Table 1) with a mean concentration of trimethylnaphthalene, 2-methyl biphenyl, 4.50 mgg-1 1.51 mgg-1 dry weight. This Fluorene, Phen/Anthr, Fluoranthene, range is by far, higher than the range (1-10 Pyrene, Benz (a) Anthr/Chrysene, Benz µgg-1) reported in Zhang et al., 2006, (b)/(k) fluoranthene, Benz (a) pyrene, associated with endogenous soils resulting Dibenz (a, h) anthr/Inden (1,2,3-cd) py and from plant synthesis and natural fires. The Benzo (ghi) perylene using GC-MS at the PAH concentration was highest in the School of Chemical, Environmental and Bolsv.1 (6.7 mgg-1) sample which is the Mining Engineering, University of sample collected about 30 m from the Nottingham. The GC-MS analysis was Coalite plant. This high concentration must performed on a Fisons instruments 8000 have been as a result of its closest proximity gas chromatograph interfaced to a MD 800 to the Coalite plant than the other samples mass spectrometer with a quadrupole mass collected. Bolsv.1 also had the highest analyzer (ionizing energy 70eV, source concentration of 2-3 ring PAHs and also 4- temperature 280° C). The gas 6 ring PAHs. This implies that the area has chromatograph capillary column is 50 m been contaminated by the Coalite plant long; i.d. is 0.32 mm and a film thickness of emissions and as such, the soil has a great 0.25µm, stationary phase is tendency to be toxic and carcinogenic. polyphenylmethylsiloxane. Lab base Generally, the 2-3 ring PAHs constituted software written by VG was used for data 65% of the total PAH concentration and the acquisition and Mass lynx for 4-6 ring PAHs constituted the remaining interpretation. The determinations were at 35% (Fig. 2). As reported by Chadwick et al. selected ion monitoring (SIM) mode. (1987) and Homann et al. (1994); Concentrations of the various PAHs were molecular structure of PAH dictates their determined using internal standard level of carcinogenicity, mutagenicity and injection. Identification of the various PAHs toxicity. Low molecular weight PAH ( was achieved by comparison with authentic rings), often display acute toxicity and low standards. carcinogenicity, while high molecular 3 Polycyclic Aromatic Hydrocarbons in Soils within the Coalite Plant in Bolsover, North Derbyshire weight PAH ( rings), show low toxicity, input and ratio > 0.5 indicates grass, wood but outstanding carcinogenicity and or or coal combustion input [13]. In this study, mutagenicity. the PAH diagnostic ratios of Flu / (Flu + Py) ranged from 0.33-0.6 (Table. 2). 20% of the Sources of PAHs soil samples had Flu / (Flu + Py) ratio < 0.4; To evaluate the risks of PAHs to the 40% had ratio between 0.4-0.5 and another environment, it is very important to find 40% had ratio >0.5. The diagnostic ratio out their origin and sources. A number of showed predominance and an equal input studies have demonstrated the usefulness of from both liquid fossil fuels combustion PAH isomer ratios in source apportionment and coal combustion. This result is as [4, 8, 15]. One of the frequently used expected as the soil samples were collected isomer ratios is the Ant/ (Ant + Phe) ratio. from areas around the Coalite plant. According to this isomer ratio, the ratio < Petroleum on the other hand, showed the 0.1 indicates petroleum input and the ratio least contribution (20%) to the PAH > 0.1 indicates pyrogenic input [2]. accumulation in the areas. However, there are limitations to the use of this isomer ratio as demonstrated by Fraser CONCLUSION et al. (1998). They demonstrated that The PAH concentrations of the study area Anthracene undergoes more rapid ranged from 0.03-2mgg-1. There was a photochemical reaction in the atmosphere predominance of the low molecular weight than Phenanthrene. The implication is that PAHs and the PAH diagnostic ratio showed during atmospheric transport, the original an equal input from liquid fossil fuel composition information will not be combustion and coal combustion. There preserved. Therefore, in order to carry out was a low contribution from petroleum an accurate PAH source apportionment in source. soils, isomer ratios where the isomer pairs degrade photolytically at comparable rates ACKNOWLEDGEMENT have to be adopted. From CCME (2008), the We acknowledge the technologists and isomer ratio Flu / (Flu + Py) is a more technicians of the instrument room in the accurate ratio as it meets with the department of Chemical Engineering of the condition. The Flu and Py isomer pair University of Nottingham for their degrades photolytically at comparable rates. technical support. The ratio < 0.4 indicates petroleum input; ratio between 0.4-0.5 indicates liquid fossil REFERENCES fuel (vehicle and crude oil) combustion 4 Journal of Engineering and Applied Scientific Research Volume 8, Number 1, 2016 [1] Arzayus, K.M., Dickhut, R.M. and Environmental Significance of Coal- Canuel, E.A. (2002) Effects of derived carbon compounds.