Assessment of Polycyclic Aromatic Hydrocarbon Contamination of Fruits, Leaves, and Soil within Automobile Repair Workshops in Nsukka Metropolis

Abstract The level and distribution of Polycyclic Aromatic Hydrocarbon (PAHs) in soil, fruit, and leaf from within automobile repair workshops in Nsukka metropolis was assessed. The PAHs concentrations were evaluated using Gas Chromatography-Mass Spectrophotometer (GC-MS). The health risk was assessed using incremental life cancer risk (ILCR) and mutagenic effect and the possible sources of the PAHs were estimated by the diagnostic ratio. The results showed that the concentrations of the PAHs in soil, fruit, and leaf ranged from 0.003 to 0.564, 0.011 to 0.070, and 0.020 to 0.120 µg/kg, respectively. The mean PAHs concentration for soil, fruit, and leaf are 0.229842, 0.034059, and 0.043091 µg/kg, respectively. The TEQs were generally within the acceptable limit stipulated by Agency for Toxic Substances Disease Registry–ATSDR (100 µg/kg) for non-pollution and low toxicity. The incremental lifetime cancer risk (ILCR) for the seven prominent carcinogenic PAHS indicated that Benzo(a)pyrene and Dibenz(a,h)anthrance, being the most toxic were above the acceptable limit of 1 × 10−4 showing possible carcinogenic effects to humans with children being the most vulnerable. Although the concentration of PAHs in this study is lower than many similar cases, they have a high risk of carcinogenesis. In contrast, the Mutagenic Equivalent Quotient (MEQ) values were generally within the acceptable value. Benzo(a)pyrene and Dibenz(a,h)anthrance were the most contributors signifying possible alternation/modification of DNA in humans. The Diagnostic ratio showed that pyrogenic combustions could be the main sources of PAHs in the studied area. Therefore, it is evident that Nsukka automobile repair area is gradually being contaminated with PAHs.


Introduction
PAHs are a persistent group of organic pollutants produced by mainly anthropogenic activities. 1 Due to their teratogenic, mutagenic and carcinogenic effects, they have been targeted by worldwide environmental and public health agencies since 1970 and have been considered as one of the most predominant organic pollutant existing in the environment as complex mixture of many congeners. 2,3They induce reactive oxygen species (ROS) overproduction and cause oxidative stress. 4They exist in several molecular arrangements; its aromatic ring can be cluster, linear or angular in shape. 5Based on the number of rings contained in each compound, PAHs can be classified into light molecular weight PAHs (LMW PAHs) and heavy or high molecular weight PAHs (HMW PAHs).PAHs with two to three aromatic rings are classified as Light-molecular weight PAHs while those with four or more aromatic ring are classified as heavy or high molecular weight PAHs. 6Based on their molecular weight, they are emitted either as gaseous form (LMW PAHs) or in the particulate form (HMW PAHs). 7,8Comparatively, it is easier for PAHs of lower molecular mass to enter an aquatic matrix than heavy PAHs. 9Due to its high lipophilicity and affinity to lipids, PAHs are moderately low soluble in water, but very soluble in most organic solvents because they are highly lipophilic. 5,10,11he formations of PAHs in the environment are mostly due to incomplete combustion either from natural combustion sources or anthropogenic combustion sources. 5,12][17] Contaminations of soils by PAH are usually due to anthropogenic activities, such as cracking of crude petroleum, burning of fossil fuels, oil spills, and incineration of industrial and domestic waste among others.Due to its high hydrophobic nature and low aqueous solubility, PAHs deposition in the soil was found to be on the increase.They adsorbed strongly on the soil particles thereby making soil ecosystem an ultimate sink for PAHs. 18,19They are persistence, nondegradable, and can be transferred into water bodies, plants, and soil from air or land. 20ontamination of soil, sediment and groundwater can lead to subsequent plant, leave, and fruit contamination. 21Crops and leaves can absorb different contaminants from polluted soil, water and air.Low concentrations might accumulate in the crop and later find their way into the environment and food chain. 22Consequently, there are two predominant routes by which PAHs in the soil are taken up by plants, 15,21 namely; soil to plant (root uptake and translocation) and shoot uptake via air or atmospheric deposition through stomata. 23More so, PAH accumulation and toxicity in vegetables and fruits depend on many factors, such as the concentration of the PAH, nature of the soil, physiological characteristics of the vegetable and fruits 24,25 and movement of PAH through the soil plant is as a result of their low solubility and high octanol water partition coefficient. 25Plants accumulate PAH from the air by intercepting or retaining particles on their leaf surface.More so, the leaf can absorb the LMW PAHs (gaseous phase) through the lipid cuticles of the leaf surface. 26,27Furthermore, leaf surfaces are covered with complex lipid cuticles that can absorb PAHs and make them difficult to be washed off by rain.Thus, PAHs adsorption on the leaf increases with an increase in the surface area and wax content of the leaf. 28n Nigeria, PAHs contaminations emerging from indiscriminate disposal of used engine oil is one of the environmental challenges and is more widespread than crude oil pollution. 29Pollution arising from uncontrollable or random disposal of organic waste and spilling of petroleum products like gasoline, lubricants, diesel fuels, used engine oils and incomplete combustion of fossil fuels, emissions from heavy vehicles and industries. 30efoh 31 described Nsukka as an environment devoid of normal hustle and bustle of fast-paced cities. Nsukka automobile repair workshop popularly called 'Site' is characterized by endless activities (vehicle and machine repair, sales of second hand auto parts, Engine oils, panel beating, and industrial processes and noise) and has become a good spot for petty traders to thrive. 32An assessment of Nsukka automobile repair area (site) shows that apart from the mechanic workshops and its similar occupations who use engine oil and carbide for welding of motor parts, various lubricants and solvents containing petroleum hydrocarbons are carelessly spilled by artisans of auto repairs.The automobile repair area is also where several industries, building materials, and motor spare parts businesses, residential areas are located.Thus, there has been a perceived increase of PAHs contaminations in the area due to an upsurge in industrial, residential, indiscriminate disposal of spent engine oil, use of carbide for welding, and other activities going on in the area.Residents and artisans are often exposed to PAH contaminations through the consumption of crops, such as vegetables and fruits grown on their private gardens or compounds.Therefore, this research is aimed at determining the possible sources, health risks associated with the consumption of the fruits and evaluating the level of PAHs in soil, leaves, and fruits from within automobile repair settlement (Site) in Nsukka urban area.

Study area and sampling
The automobile repair shops (Figure 1) popularly referred to as 'Site' by the inhabitants as well as auto repair customers is located in Nsukka urban, Nigeria.The area lies between 6 50 0 33.7 00 N and 7 22 0 40.5 00 E latitude and longitude.The auto mechanic shops covered a large expanse of land estimated at seven thousand square meters. 31,32Aside the automobile repair workshops, the area houses many other industries, such as Noodles manufacturing company, Vegetable oil, local bread manufacturing companies, and local restaurants amongst others.More so, the area is housing building materials and motor spare parts dealers.The area experiences two seasons (rain and dry seasons) each year.The rainy season starts from early March to late October with May to August having the greater amount of rain each year while December to February has been experienced to have the highest effect of dryness each year.A total of 45 composite samples (soil, plant, and fruit) were collected.Five samples from each sampling area representing the four major demarcations of the site were collected.The soil samples were collected from 0 to 30 cm depth within the clusters of the author repair shops.Grassland vegetation is predominant in the study location which according to Mbagwu; 33 Edeh et al., 34 is within the forest-savanna transition vegetation zone.The area has an ustic soil moisture regime and the soil around are characterized as being well drained with very low total exchangeable base, cation exchange capacity(CEC), and base saturation. 34The soil is deep, coarse textured, and low in organic matter with perennial leaching problem. 34The soils mostly belong to the order of Ultisol and Vertisol.There are lots of trees around the workshops which shed its leafs.These leafs are burnt by the shop owners on weekly basis during the dry season.The fruit and leaf samples were collected from Persea americana (Avocado pear), Irvingia gabonensis (African mango), Magnifera indica (Mango), and Dacryodes edulis (African pear).These are the four most common, with (edible fruits) trees that grow within the author repair workshop clusters.The samples collected from various sampling points were air dried, pulverized, and sieved through a 2 mm sieve.The leaf and fruits samples were collected from public places with the permission of the author repair workshop owners who eat these fruits and edible leaf (vegetables) around the workshops.The composite samples were stored in the laboratory at 4 C and analyzed within 6 days.The whole part of the study complied with the local and national guidelines on studies involving soil, plants, and fruits.

Topography, geology, and climate of Nsukka
Nsukka has a land area of 40,750 km 2 with a mean elevation of 1810 ft (552 m) above sea level and has an estimated population of 309,448 as of 2006. 35,36Based on Koppen's climatic classification scheme, the climate of Nsukka is classified as the tropical wet and dry climate. 37The area receives enough sunshine throughout the year.It has an average daily maximum and minimum temperature of 27 and 23.3 C, respectively, while its average monthly maximum temperature is about 31.5 C. 36 Rainfall in Nsukka is very high and intense.The average monthly rainfall ranges from 250 mm in April to 380 mm in October, with a mean annual total of 1500 mm. 36The rainless period of the year (dry season) in this region lasts from November to March while the wet season spans from April to October.The harmattan season characterized by the dry and dusty northeasterly trade wind occurs between the end of November and the end of February.It is underlain mainly by two geologic formations, that is, the false bedded sand stone (Ajali sandstone) and Lower Coal Measure (Nsukka Formation).The soils of Nsukka L.G.A are classified into two major groups, namely: ferrallitic soils (deep porous red soils derived from sandy deposits, and the red and brown soils derived from sandstones and shales), and hydromorphic soils.Agriculture is the most predominant socio-economic activities engaged by the inhabitants of the area.The farmers in the area plant different species of crops like yams, cassava, cocoyam, pigeon peas, pepper, maize, and vegetables.Cash crops like palm produce, tobacco, kola, oranges, mangoes, and so many other fruit plants grow very well in the region too.36a

Extraction, clean-up, and PAHs determination
The standard method used was based on EPA Method 3630 C. 5 g of properly homogenized samples were weighed into beakers and mixed with 10 mL hexane: Acetone (1:1) mixture.The beakers were then placed into an ultrasonic bath and sonicated for 20 min.The mixture was allowed to settle and solvent layer was decanted and concentrated down to 2 mL using a rotary evaporator.Silica gel was activated by heating at 130 C for 16 h and then stored in a desiccator.A glass column was packed with 5 g of silica gel and1g of anhydrous sodium tetraoxosulphate (VI) (Na 2 SO 4 ) was added.Twenty milliliters n-Hexane was added to the column and eluted into a beaker.
The 2 mL sample extract was added to the top of the column quantitatively and another 10 mL of n-Hexane was added to the column and eluted to waste.Before the column head dried out, 10 mL (1 þ 1) dichloromethane þ Hexane was added and the eluent was collected.The eluent was then concentrated to 2 mL using a rotary evaporator and analyzed.
Before calibration, the MS was auto-tuned to perfluorotributylamine (PFTBA) using already established criteria to check the abundance of m/z 69, 219, 502, and other instrument optimal & sensitivity conditions.Determination of the levels of PAHs in the sample was carried out using GC-MS by operating MSD in selective ion monitoring (SIM) and Scan mode to ensure low level detection of the target constituents.Agilent 6890 N gas chromatograph coupled to 5973 C inert mass spectrometer (with triple axis detector) with electron-impact source (Agilent Technologies) was used.The stationary phase of separation of the compounds was HP-5 capillary column coated with 5% Phenyl Methyl Siloxane (30 m length Â 0.32 mm diameter Â 0.25 mm film thickness À Agilent Technologies).The carrier gas was hydrogen used at constant flow of 1.48 mL/min at an initial nominal pressure of 1.49 psi and average velocity of 44.22 cm/s.One microliters of the samples were injected in splitless mode at an injection temperature of 300 C. Purge flow to spilt vent was 15.0 mL/min at 0.75 min with a total flow of 16.67 mL/min; gas saver mode was switched off.Oven was initially programmed at 40 C (1 min) then ramped at 12 C/ min to 300 C (10 min).Run time was 32.67 min with a 3 min solvent delay.The mass spectrometer was operated in electron-impact ionization mode at 70 eV with ion source temperature of 230 C, quadrupole temperature of 150 C, and transfer line temperature of 300 C. After calibration, the samples were analyzed and corresponding PAHs concentration obtained.The facilities at the CTX-ION Analytics Ltd, Ikeja Lagos, Nigeria were used.

Limit of determination (LOD) and limit of quantification (LOQ)
PAHs extraction efficiency was evaluated using recovery method.A known concentration of a standard PAH mixture was added to analyze samples and re-analyze in different days.Recoveries for the PAH compounds were in the range of 82.4-94.2%.The LOD was determined on the basis of signal to noise ratio of 3 while LOQ was determined on the basis of signal to noise ratio of 10.LOD was determined by continuous dilution and analysis of standard solution until the least concentration was obtained at the signal to noise ratio of 3. Likewise, LOQ was determined by continuous dilution and analysis of standard solution until the least concentration was obtained at a signal ratio of 10.

Toxic equivalency factor
The toxic equivalent concentration of a PAH mixture can be assessed by converting the PAH concentrations in the mixture to an equivalent concentration of Benzo(a)pyrene (BaP). 38The carcinogenic potency of PAHs was calculated relative to that of BaP as a reference compound. 39The toxicity equivalent concentration can be applied in any environmental media to estimate the carcinogenic risk of PAH mixtures. 40For more accurate measurement of carcinogenic potency of PAH mixtures, recent studies have estimated up to 88 PAHs both in gaseous and particle phases. 41[44][45] Where TEQ ¼ Toxic equivalents of reference compound, cPAH ¼ Concentration of PAH congener, and TEF ¼ Toxic equivalency factor for PAH congener.

Cancer risk assessment
The International Agency for Research on Cancer (IARC) estimated the carcinogenic risk of PAHs in humans based on inference from existing experimental data.From the estimation, Benzo(a)pyrene, was classified as carcinogenic to humans, Dibenz(a,h)anthracene and benzo(a)anthracene were classified as probably carcinogenic to humans, Benzo(b)fluoranthene, Benzo(j)fluoranthene, Benzo(k)fluoranthene, chrysene, Naphthalene and Indeno(1,2,3-cd)pyrene were classified as possibly carcinogenic to humans while other considered PAHs due to their limited experimental evidence were not classifiable with regard to their carcinogenicity to humans. 47,480][51] It was evaluated by multiplying the chronic daily intake (CDI), Cancer Slope Factor of BaP (CSF), and conversion factor CF (10 À3 mg/ng) as shown in Equation (3) 52,53 .For ILCR, the value <10 À6 shows no or negligible risk while 10 À4 implies greater risks with adverse health effects like cancer. 455][56][57] Chronic daily intake (CDI) [mg/kg body mass (BM)] in the fruit sample was calculated using Equation (4) according to Taghizadeh et al. 58 Table 1 presents the parameters used in calculating the ILCR and the CDI.

PAH diagnostic ratio analysis
The possible sources of the polycyclic aromatic hydrocarbons in the studied area were estimated using the four most used molecular diagnostic rations-Fla/(Fla þ Pyr), Ant/(Ant þ Phe), BaA/ (BaA þ Chry), I(cd)P/(I(cd)P þ B(ghi)P).They were calculated to distinguish among the two (Petrogenic and pyrogenic) predominant sources of PHAs in the environment.

Results and discussions
The LOQ and LOD showed a low concentration of the PAHs.The result showed LOD range of 0.00012-0.00892mg/kg and LOQ of 0.00036-0.02676mg/kg (Table 2).This result indicated a significant PAHs extraction efficiency having a percentage range of 89 to 99% recovery.The analysis results of the polycyclic aromatic compound obtained in the auto mechanic shops in Nsukka metropolis are shown in Table 3 (Figure 2).The results obtained were generally low with the mean concentration of 0.43678, 0.064333, and 0.079 mg/kg for soil, fruit, and leave, respectively.Higher concentrations of PAHs congeners were obtained in the soil with a total PAHs concentration of 4.3678 mg/kg.This implies that the soil serves as a sink for these environmental contaminants.Unlike the soil, the fruit and the leave samples had a total concentrations of PAHs less than unity (0.579 and 0.474 mg/kg, respectively) indicating the low-level of the contaminants in fruits and leave of the trees around and within the study area.This result is in line with the recent study which showed that the summation of PAHs in soil is generally higher than in plants. 3,61Thus, the PAHs with the highest concentration were; Benzo[g,h,i]perylene (0.564 ± 0.481), Chrysene (0.525 ± 0.602), Dibenz(a,i)pyrene (0.513 ± 0.593), Indeno[1,2,3-cd]pyrene (0.468 ± 0.854).In soil, the HMW compounds were more predominant when compared to the low molecular weight PAH (LMW and medium molecular weight (MMW) PAHs.The predominance of heavy molecular weight (HMW) PAHs showed that the sources could be as a result of high level of anthropogenic activities, such as emission from the activities of the industries, residential and heavy traffics in this area. 62Acenaphthene was not detected in any of the samples while Acenaphthalene and Fluorene were only detected in soil.The lower concentration values of the LMW PAHs could be linked to its high volatility and dissolution. 30The lower value of LMW PAHs against HMW PAHs in the soil is similar to the report of Ofomata and Okoye 63 on assessment of the level of contamination, toxicity, and PAHs sources in the soil of an emerging industrial town in south East, Nigeria, 64 on PAHs assessment in soil situated around solid waste dumpsite in Awka, Nigeria.Most of the HMW PAHs were not detected in the leaf.This is in agreement with previous reports that LMW and MMW PAHs are taken up by plants more than the HMW PAHs because HMW are often times retained in the soil. 65,66More so, HMW PAHs are rapidly deposited near their origins or sources and are less mobile, while LMW and MMW PAHs showed higher mobility and wide dispersion when compared to HMW PAHs due to its abundant in the gaseous phase. 27,67detunde et al. 68 assessed the level of PAHs in vegetables [(Corchorus olitorius (Ewedu), Celosia argentea (Soko), Amaranthus cruentus L. (Grain amaranthus/Tete), Telfairia occidentale (Ugu), Basella alba (Amunu tutu/White Spinash), Lactuca sativa (Lettuce), Allium ascalonicum (Spring Onions/Alubasa elewe), Talinum triangulare (Water leaf)] grown on contaminated soils in a Sub-Saharan tropical environment, Lagos, Nigeria.they reported that the total PAH concentration in the contaminated soils and plants grown on them were 200-250,000 and 100-5000 ng g À1 , respectively.They also noted that the two and three ringed PAHs which are the less toxic were the  dominant PAH type present in most of the plant parts.Tesi et al., 69 assessed the level of PAHs in Four commonly consumed leafy vegetables in southern Nigeria and reported that the mean concentration (mg kg À1 ) of P 16 PAHs in the vegetables ranged from 532 to 2261.They indicated that the estimated margin of exposure (MOE) values were <10,000, indicating that the vegetables were unsuitable for consumption.The HI values were < 1, suggesting that there were no potential noncarcinogenic risks, but the total cancer risk values (> 1 Â 10 À6 ) designated carcinogenic risk of PAHs with consumption of these vegetables.Paris et al. 70 in the polycyclic aromatic hydrocarbons assessment in fruits and vegetables noted that rather low amounts of PAHs are usually detected in raw fruits and vegetables.
The toxicity equivalent factor (TEF) and Benzo[a]pyrene equivalent concentration of the samples in mg/kg calculated values (Table 4) were all <100 mg/kg as stipulated by ATSDR for nonpollutant and low toxicity (ATSDR).In 2006, European food safety authority (EFSA) adopted Benzo[a]pyrene as the standard for measurement of contaminations of food by PAHs and assessment of possible effect of carcinogenic PAHs and had set 2 mg/kg w/w Bap as the maximum allowable value for many foodstuffs. 14Thus, in this study, the low values of other BaPs recorded in this study should not be neglected considering that there is no threshold concentration at which carcinogenic effects of PAH do not occur.However, this showed that the PAHs in this study area are of utmost concern since PAHs bio-accumulate and cause serious health problems when they enter food chain.
The PAHs diagnostic ratios (Table 5) were calculated using the four prominent diagnostic ratios.The values of the Ant/(Ant þ phe), IdP/(IdP þ BghiP), and BaA/(BaA þ Chry) ratios indicated pyrogenic sources which may be attributed to the identified possible sources of PAHs from author mechanic shops (coal, wood, and biomass burning and exhaust from various industrial related activities in the area) while the Fla/(Fla þ pry) values showed petrogenic sources linked to crude oil and spent engine oils used in the sampling area.The difference in the sources of PAHs based on Fla/(Fla þ pry) diagnostic ratio could be attributed to high conservative ratio.Previous reports have identified that Fla and Pry showed lower sensitivity to degradation due to its high conservative ratio. 74While BaA/(BaA þ Chry) showed high sensitivity to photo-degradation. 77][73] sources of PAHs in the studied area.This is in line with the report of Tobiszewski and Namie snik; 74 Katsoyiannis and Breivik; 77 Sadeghdoust et al. 78 It should be noted that diagnostic ratio as a means of source apportionment of PAHs has some uncertainties. 79Although parent PAH diagnostic ratios may provide important information pertaining to pollution emission sources, the arbitrary application of PAH diagnostic ratios has been under scrutiny. 79Some authors have applied them unaware of the fact that they are not usually conservative in the environment.Most diagnostic ratios involve pairs of PAHs with the same molar mass and similar physicochemical properties so they are assumed to undergo (oxidation and photo-oxidation, resulting in their modification during PAH transport due to the preferential degradation of some PAHs) similar processes determining their fate in the environment. 1,80sk assessment Health risks Assessments due to exposure to PAHs were evaluated.The ILCR (Table 6) were estimated for PAHs exposure in adults and children.The result obtained showed that the ILCR values for the seven carcinogenic PAHS in fruit sample range from 0.62 Â 10 À5 to 91 Â 10 À5 for adults and 0.49 Â 10 À4 to 71.50 Â 10 À4 for children.The sum of ILCR for the seven carcinogenic PAHs was 159.49Â 10 À5 for adults and 144.71Â 10 À4 for children.Thus, in this study, the estimated carcinogenic risk for humans in fruit samples were generally >10 À5 except Chrysene in adults and >10 À4 except chrysene in children.B(a)P and DiahA have highest values of 91.01 and 50.70, respectively, and reported as contaminates with the highest risk showing serious cancerous effect to both adults and children. 81Reports have shown that the carcinogenic effects of PAHs are more prominent in some body parts, such as gastro-intestine, liver, lung, bladder, and skin. 42,82he MEQ values in the fruit sample (Table 7) for the seven carcinogenic PAHs (BaA, Chry, BbF, BkF, BaP, BgP, and IN) were calculated.The total MEQ values were 0.07722 mg/kg With BaP comparatively higher in concentration than others.The result of the calculated values shows that the MEQ values range from nd to 0.070.The metabolites of BaP were said to cause modifications in human DNA and highly carcinogenic. 30The MEQ values for carcinogenic PAHs were generally low.However, since PAHs bioaccumulate in the living tissue, the low values obtained in PAHs: polycyclic aromatic hydrocarbons; CSF: cancer slope factor; cPAHs: carcinogenic PAHs; RI: risk index. 42,46,56,61,81his study should be of concern to the residents and auto repairers considering that there is no threshold concentration at which carcinogenic effects of PAHs does not occur.Varimax rotated component matrix was used to understand the PAHs' sources in soil, fruit, and leave (Table 8).Two rotated factors (Figure 3) were acquired for all the three matrices with a cumulative eigen value of 100.00%, for the different PAHs.Naphthalene, Pyrene, Chrysene, and Benzo[a]pyrene gave the major contribution to the first factor (PC1) while the second factor (PC2) received the major contributions from Chrysene, Indeno[1,2,3-cd]pyrene, Benzo[ghi]perylene and Dibenzo(a,i)pyrene (Table 9).This observation suggests their similar sources as noted by Ihedioha et al. 84 Based on this, we surmise that the PAHs which are of pyrogenic sources, emerges from indiscriminate disposal of spent engine oil, incomplete combustion of fossil fuels, the use of carbide for welding of motor parts, emission from heavy trucks, and oil milling within the study area.

Spatial distribution of PAHs within the study area
Spatial distribution map of the PAHs that have relative concentration were drawn and according to the spatial interpolation results (Figures 4(A-L)), the PAHs in the auto mechanic shops displayed a characteristic aggregation, with multiple centers, with areas of high concentrations in the southeast of the study area where there are Odulauto, Hilltop plaza (a concentration of author repair shops).Benzo[a]anthracene, Dibenzo[a,h]anthracene, and Pyrene are distributed more in this area (Figures 4(B-D)).The PAHs concentrations in this region are from non-point sources and mobile sources mixed and eventually deposited on the soil to form regional baseline deposits. 85,86Potential point sources of PAHs are scattered around the auto mechanic workshops.Chrysene and Indeno[1,2,3-cd]pyrene (Figures 4(E,F)) were mostly distributed in the northwest of the study area were the noted possible contamination sources are oil mill, Innotina plaza, Deu energy Intl.Ltd and Benko ventures.No significant high values were found in eastern region of the study area with Benzo[e]pyrene being the most concentrated PAH.Figures 4(H,K   the eastern region and Benzo[a]pyrene and Benzo[b,j,k]fluoranthene (Figures 4(A,G)) in the northeast area.

Conclusion
This work evaluated PAHs in soil, fruit, and leaf in automobile repair workshops in Nsukka using GC-MS.The health risk assessments of the PAHs in fruit for both adult and children were estimated using ILCR.The concentrations of the HMW PAHs were higher in the soil and showed lower concentration in the fruit while most of the HMW PAHs were not detected in the leaf         sample except B(bjk)P, BeP, and BaP.From the study, the sum concentrations of the 20 PAHs showed a distribution trend as follows: Soil > Fruit > Leaf.The analysis of the contaminant sources showed that the sampling area is fairly polluted with polycyclic aromatic hydrocarbon predominantly from pyrogenic sources.Although the concentration of PAHs in this study is lower than many similar cases, they have a high risk of carcinogenesis.The health risk assessments of the PAHs in fruit revealed that carcinogenic risk were observed in children and adults especially.In children the values of DiahA, BaP, and BaA were above 10 À4 showing the probability of carcinogenic risk.Moreover, the values of MEQs were low with BaP having the highest concentration value.Therefore, from this study, it is evident that the Nsukka automobile repair area is gradually being contaminated with PAHs emerging from indiscriminate disposal of spent engine oil, incomplete combustion of fossil fuels, the use of carbide for welding of motor parts, emission from heavy trucks, and increase in industrial and residential activities as the area expands with more business and industrial outlets.There is a need to put the activities of these artisans under control.

Figure 1 .
Figure 1.GIS map of Nsukka showing the mechanic village.

Figure 2 .
Figure 2. Individual PAHs concentration in soil, fruit, and leaf samples.
) depict the spatial distribution of Benzo[g,h,i]perylene and Dibenzo[a,i]pyrene, respectively in the western region of the study area, while the spatial distribution of Anthracene and phenanthrene are shown by Figures 4(I,L), respectively in the southern region.Others are Benzo[e]pyrene (Figure 4(B)) in

Figure 4 .
Figure 4. Spatial distribution of PAHs within the study area.

Table 2 .
Limit of detection and quantification.

Table 3 .
Mean PAHs concentration in the samples in mg/kg (mean ± SD) n ¼ 3.

Table 7 .
MEQ of PAHs of fruit samples.

Table 8 .
Varimax rotated component matrix for PAHs loading in soil, fruit, and leave.

Table 9 .
The PAHs principal component scores.