International Research Journal of Environment Sciences________________________________ ISSN 2319–1414Vol. 3(11), 57-64, November (2014) Int. Res. J. Environment Sci. International Science Congress Association 57 Characterization and Source identification of Atmospheric Polycyclic Aromatic Hydrocarbons in Visakhapatnam, IndiaKulkarni K.S.1*, Sahu S.K., Vaikunta Rao L., Pandit G.G. and Das N. Lakshmana1 GITAM Institute of Science, GITAM University, Visakhapatnam-530 045, INDIA Environmental Monitoring and Assessment Section, Bhabha Atomic Research Centre, Trombay, Mumbai-400085, INDIA Available online at: www.isca.in, www.isca.me Received 28th September 2014, revised 15th October 2014, accepted 20th November 2014 AbstractPolycyclic aromatic hydrocarbons (PAHs) are considered to be hazardous atmospheric contaminants due to their carcinogenic and mutagenic properties. In the present study, 16 particle bound polycyclic aromatic hydrocarbons were determined in air particulate matter samples (PM10collected during March 2010 to February 2011 at an industrial cum residential area in Visakhapatnam, Andhra Pradesh. The samples were investigated for atmospheric concentrations, seasonal variation and potent sources of PAHs. Particulate matter samples were collected on glass fiber filter papers using high Volume Sampler and analyzed by HPLC/UV-VIS detector. The annual concentrations of total PAHs varied between 23.3 to 104.9 ngm 3. The dominating PAHs were Acy, Ace, Phen, Pyr, B(ghi)P, B(a)P, and B(k)F. The PAHs concentrations were found to be elevated in winter than summer and monsoon. The total PAHs concentration during winter was about twice than the concentrations in summer and about 2.6 times higher than the concentration in monsoon. Higher PAHs concentrations in winter were mainly due to the privileged meteorological conditions in winter. The two and three ring PAHs were predominant than four, five and six ring PAHs and contributed to about 56% of total PAHs. The correlation studies showed that meteorological conditions such as temperature, relative humidity and rainfall strongly affected the PAHs concentrations. Principal component analysis (PCA) studies of the data indicated that coal combustion, diesel and gasoline powered vehicular emissions, lubricating oil burning and stationary sources like steel plant were the major sources of PAHs at study site. Keywords: PAHs, seasonal variation, correlation, principal component analysis. Introduction The expanding human population pressure is causing aggressive industrial growth in developing countries. But, increased energy demands for industries and commercial establishments have resulted in serious environmental destruction. Thousands of industrial effluents are generating untreated toxic waste in air, water, and soil. The impact of this environmental disaster is studied in last few years like influence of dye industrial effluent on soil, impact of industrial effluent discharge on agricultural soil, levels of heavy metals in urban sewage water and impact of human activities on quality of water etc2-5. Polycyclic aromatic hydrocarbons are the toxic organic compounds getting attention due to their carcinogenic and mutagenic properties. At ambient temperature PAHs are present in air both in gaseous and particulate phase. Low molecular weight PAHs tend to be more concentrated in the vapor-phase while the high molecular weight are often associated with particulates. Particle-bound PAHs are considered to be the most hazardous to human health as particulates with aerodynamic diameters 10m (PM10) and 2.5m (PM2.5) are easily inhaled and exposure of them may cause lung cancer, morbidity and cardiopulmonary diseases. PAHs are generated and emitted during incomplete combustion processes of fossil, non-fossil fuelsand the release of petroleum products. PAHs originate mainly from anthropogenic sources such as household fuel burning, vehicular emissions, various industrial emissions and agriculture burnings. PAHs can persist in the environment for long time and they show ability to get transported at long distances. They get accumulated in industrial and heavy traffic areas and also found in remote regions. PAHs and their derivatives have shown carcinogenic and mutagenic effects. Studies have proved that workers exposed at coke ovens in coal coking, coal gasification, asphalt foundries and aluminum production plants suffered with lung cancer. It was found that chimney sweepers suffered from skin cancers and scrotal cancers due to high dermal exposure to the PAH compounds. In last few years, a lot of work is carried out on airborne PAHs in many cities all around the world. In India the studies on PAHs are carried out in various cities like Mumbai, Delhiand Tiruchirapalli10-12. The current study focuses on the concentration, seasonal variation and the estimation of potent sources of particle bound PAHs at Visakhapatnam through the sampling program of one year. For this city, not much data is available on particle bound PAHs. So, this work will provide information about the levels of these toxic and mutagenic compounds and will be helpful to set control measures to prevent their harmful effects on environment. International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 3(11), 57-64, November (2014) Int. Res. J. Environment Sci. International Science Congress Association 58 Material and Methods Sampling site and sample collection: Visakhapatnam (Latitude 1741’18”N, Longitude 8313’07”E), commonly known as “Vizag” is the second largest city in the state of Andhra Pradesh on the east coast of India. The population is around 1.7 million as per census 2011. The rapid urbanization has resulted in the increased utilization of fossil fuels for transportation and industrial purposes. The city has tropical type of climate with excessive humidity. The summer season is from March to June when the temperature is around 45°C. The monsoon season is from July to October with irregular showers and the North-East winds are the major source of rainfall. The annual rainfall was about 95 centimeters during study period. The winter season is from November to February with average temperature of 25°C. For the study, sampling location was selected at an industrial cum residential area named “Paravada”. The site is about 8 km away from the national highway. The site has many industries in surrounding area such as NTPC (Simhadri), Bharat Heavy Plates, Steel Plant, BHPV and Nehru pharma city etc. Figure-1 shows the map of sampling site at Visakhapatnam.Sampling was carried out from March 2010 to February 2011. For sampling USEPA guidelines were followed. PM10 samples were collected using High Volume Sampler (Envirotech Respirable Dust Sampler, APM 460) and glass fiber filter papers of size 18 x 20 cm. The sampling was conducted weekly once for 24 h at the rate of 1.1 mmin 1. Filter papers were kept in desiccators before and after sampling to remove the moisture. After sampling, the filter papers were wrapped in aluminum foils and kept at cold place until extraction and analysis.Extraction and Analysis of PAHs: One forth portion of the filter paper was cut into pieces and taken into conical flasks. They were extracted with 30 ml of HPLC grade n-hexane for 1h using ultrasonic technique. The extracts were filtered and concentrated to about 1ml. Then it was subjected to a column cleanup process. The extract was loaded on the top of a column (10 cm×1.0 cm i.d.) packed with slurry of silica gel. The column was eluted with n-hexane to give a fraction enriched with PAH. The PAH containing fraction was concentrated to 1ml by passing gentle stream of ultra-pure nitrogen. After this, it was stored in test tubes. The analysis of the extracts was carried out for 16 EPA priority PAHs including Naphthalene [Naph], Acenapthylene [Acy], Acenapthene [Ace], Fluorene [Fluo], Phenanthrene [Phen], Anthracene [Anth], Fluoranthene [Flt], Pyrene [Pyr], Benzo(a)Anthracene [B(a)A], Chrysene [Chry], Benzo(b) Fluoranthene [B(b)F], Perylene[Pery], Benzo(k) Fluoranthene [B(k)F], Benzo(a) Pyrene [B(a)P], Benzo(ghi)Perylene [B(ghi)P], and Indeno (1,2,3- cd)Pyrene [IP]. The identification of PAHs was carried out using HPLC (high performance liquid chromatography) system supplied by Shimadzu, LC-10 AD, Japan. In this system, column length was 250 mm and inner diameter was 4.6mm. It was filled with porous spherical particles. A guard column was also provided with length 10 mm and inner diameter 4.6-mm. For the analysis, mobile phase used was Acetonitrile (88%) and water (12%) mixture in isocratic mode. The flow rate was maintained at 0.85 ml/min. A UV-VIS detector was used which was set at 254 nm for identification of the peak of PAH compounds. The output signal of the detector was analyzed by Jasco–Borwin workstation. Quality control: After sampling, all filter papers were kept at low temperature and extracted before 15 days from the sampling. The concentrations of PAHs were calculated using the retention times and areas under the peaks of the samples with standards. The limit of detection of the chromatographic method determined through serial dilution of the PAH standard varied between 0.007 to 0.016 ng for the different compounds. Blanks filter papers were extracted and blank samples were also run during analysis to avoid gravimetric and instrumental error. Figure-1 The map showing sampling site at Visakhapatnam International Research Journal of Environment Vol. 3(11), 57-64, November (2014) International Science Congress Association Results and Discussion Concentrations of PM10 and PAHs: The annual average concentrations of individual PAHs measured in the PM presented in table- 1. The concentrations of individual PAHs varied between 0.11 to 18.5 ngm-3 . The concentrations of total PAHs (TPAHs) varied be tween 23.4 and 104.9 ngm average concentration of 57 ngm-3 . Maximum TPAHs concentration was observed in the month of January (101.1 ngm-3 ) while minimum TPAHs concentration was observed in the month of August (24.3 ngm-3 ). TPAHs concentrations showed variability due to meteorological variations during the sampling period. Concentrations of Acy, Fluo, Ace and Phen were highest amongst all PAHs. These are the significant low molecular weight PAHs found in fly ash from coal plant13. Significantly high levels of B(ghi)P and Phen which are generally contributed by motor vehicle emissions were observed in the samples. The concentrations of B(a)P, B(a)A, Chry, Pyr and B(k)F were also found high which are potent carcin The sources of Fluo, Phen and IP are incomplete combustion and pyrolysis of fuels Table-1 Minimum (MIN), maximum (MAX) and average (AVG) concentrations of individual PAH in ngm Visakhapatnam Pahs Min Max Naph 1.0 6.3 Acy 7.4 18.5 Fluo 1.5 9.7 Ace+Phen 3.5 16.1 Anth 0.7 6.3 Flt 0.7 4.3 Pyr 0.6 10.8 Chry+BaA 0.6 5.9 BbF 0.3 5.9 BkF 0.3 6.7 Pery 0.2 3.9 BaP 0.2 3.5 IP 0.1 5.6 BghiP 2.6 17.7 The sum of the major combustion specific compounds which include Fluo, Pyr, B(a)A, Chry, B(b)F, B(ghi)p, B(a)P, IP and B(k)F was found to be 23.4 ngm-3 and the ratio of their sum with the sum of the 16 EPA-PAHs ( COMB/TPAHs) was 0.41. IARC listed carcinoge nic PAHs were further classified as ‘ probably carcinogenic’ to humans (namely BaA, BaP and DbA) and as ‘possibly carcinogenic’ to humans (namely BbF, BkF and IP). These potent carcinogenic PAHs (excluding DbA) accounted for 18% of the total PAHs. Table-2 shows the present results compared with the data of other cities in India and all over the world with similar background. It was found that TPAHs concentrations were quite Environment Sciences_______________ _________________________ International Science Congress Association The annual average concentrations of individual PAHs measured in the PM 10 are 1. The concentrations of individual PAHs . The concentrations of total tween 23.4 and 104.9 ngm -3 with . Maximum TPAHs concentration was observed in the month of January (101.1 ) while minimum TPAHs concentration was observed in ). TPAHs concentrations showed variability due to meteorological variations during the sampling period. Concentrations of Acy, Fluo, Ace and Phen were highest amongst all PAHs. These are the significant low molecular weight PAHs found in fly ash from coal based power Significantly high levels of B(ghi)P and Phen which are generally contributed by motor vehicle emissions were observed The concentrations of B(a)P, B(a)A, Chry, Pyr and B(k)F were also found high which are potent carcin ogenic. The sources of Fluo, Phen and IP are incomplete combustion Minimum (MIN), maximum (MAX) and average (AVG) concentrations of individual PAH in ngm 3 at Avg 3.0 12.5 5.0 9.1 2.8 1.8 3.6 2.2 2.0 2.4 1.2 1.7 2.0 7.7 The sum of the major combustion specific compounds which include Fluo, Pyr, B(a)A, Chry, B(b)F, B(ghi)p, B(a)P, IP and and the ratio of their sum COMB/TPAHs) was 0.41. nic PAHs were further classified as probably carcinogenic’ to humans (namely BaA, BaP and to humans (namely BbF, BkF and IP). These potent carcinogenic PAHs (excluding DbA) shows the present results compared with the data of other cities in India and all over the world with similar background. It was found that TPAHs concentrations were quite higher in other metropolitan cities like Agra, Delhi and Tiruchirapalliin India and cities in Hong Kong Visakhapatnam7,11-15 . While concentrations in cities from Greece and Turkey were lower than the present study Distribution of PAHs having different number of Benzene Rings: PAHs are classified by the presence of number of aromatic rings. The classification is as follows: 2 including Nap; 3- rings including Acy, Ace, Flu, Phen and Ant; 4- rings including Flt, Pyr, B(a)A and Chry; 5 B(b)F, B(k)F, B(a)P, Pery and 6- rings including IP and B(ghi)P. PAHs having more aromatic rings, in general, represent higher molecular weights. Figure-2 s hows the percentage composition of PAH compounds having different number of Benzene Rings. There were high concentrations of 2 contributed around 6% and 50% of total PAHs mass. The PAHs with 4, 5 and 6 rings PAHs contributed 13%, 13% and 18%, Figure - Percentage Composition of PAH compounds having different number of Benzene Rings Seasonal Variations: Table- 3 represents seasonally analyzed data of each PAHs concentration concentrations of PAHs are higher in the winter than in the monsoon and summer which is in accordance with earlier studies where particle bound PAHs in winter than summer and monsoon concentrations of TPAHs were 88.9; 46.1 and 34 ngm winter, summer and monsoon, respectively. It was also observed that an average winter concentration of TPAH was about twice than the average summer TPAH concentration and about 2.6 times higher than average monsoon TPAH concentrations. Generally, the levels of concentrations of TPAHs throughout the year mainly depend upon atmospheric conditions. The concentrations of PM and related PAHs in atmosphere, generally decrease with increasing temperature and frequency of the rain16 . In winter, slow speeds of decrease the dispersion of pollutants. Therefore, PAHs concentrations are found higher in winter. In summer, increased dispersion of pollutants is observed due to fast speeds of wind 5.5 49.7 13.313.118.4 _________________________ ______ ISSN 2319–1414 Int. Res. J. Environment Sci. 59 higher in other metropolitan cities like Agra, Delhi and cities in Hong Kong and Taiwanthan . While concentrations in cities from were lower than the present study 16,17 Distribution of PAHs having different number of Benzene PAHs are classified by the presence of number of aromatic rings. The classification is as follows: 2 -rings rings including Acy, Ace, Flu, Phen and Ant; rings including Flt, Pyr, B(a)A and Chry; 5 -rings including rings including IP and B(ghi)P. PAHs having more aromatic rings, in general, represent higher hows the percentage composition of PAH compounds having different number of Benzene Rings. There were high concentrations of 2 and 3 ring PAHs which contributed around 6% and 50% of total PAHs mass. The PAHs with 4, 5 and 6 rings PAHs contributed 13%, 13% and 18%, respectively. - 2 Percentage Composition of PAH compounds having different number of Benzene Rings 3 represents seasonally analyzed concentration . It was found that the concentrations of PAHs are higher in the winter than in the monsoon and summer which is in accordance with earlier studies where particle bound PAHs concentrations were higher in winter than summer and monsoon 14. The average concentrations of TPAHs were 88.9; 46.1 and 34 ngm -3 for winter, summer and monsoon, respectively. It was also observed that an average winter concentration of TPAH was about twice than the average summer TPAH concentration and about 2.6 times higher than average monsoon TPAH concentrations. levels of concentrations of TPAHs throughout the year mainly depend upon atmospheric conditions. The concentrations of PM and related PAHs in atmosphere, generally decrease with increasing temperature and frequency of . In winter, slow speeds of wind and cold temperatures decrease the dispersion of pollutants. Therefore, PAHs concentrations are found higher in winter. In summer, increased dispersion of pollutants is observed due to fast speeds of wind 2 rings 3 rings 4 rings 5 rings 49.7  International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 3(11), 57-64, November (2014) Int. Res. J. Environment Sci. International Science Congress Association 60 and hot temperature. This leads to decrease in the concentration of PAHs in summer11. In monsoon, the PAHs are washed away due to rainfall causing less concentration as compare to winter and summer14. The effect of meteorological conditions on PAHs was well explained when winter to summer (W/S) concentrations and winters to monsoon (W/M) concentrations ratios were compared. The W/S and W/M ratios for individual PAH at the study area are given in figure-3. The W/S ratio for TPAHs was around 1.9 and that of the W/M ratio was around 2.6. The W/M ratios were higher than the W/S ratios which shows that for removal of PAHs from the atmosphere, wash out effects due to precipitations in monsoon are stronger than other PAH removing effects like photo degradation, biodegradation, chemical oxidation and various atmospheric effects in the summer. One more reason behind the higher concentrations of PAHs in winter could be the higher emissions from combustion of fossil fuels for cooking and other central heating activities16,17. Also their levels in the ambient environment depend upon traffic and the industrial activities18. Table-2 Mean/Range of TPAHs concentrations (ngm) in various countries around the world with different backgrounds and methods of extractionCountries Cities Extraction /Analysis Mean/Range of TPAH (ng/m3) Samples collected Site discription India (Present study) Visakhapatnam Acetonitrile-water/HPLC 57 ngm-3 PM10Industrial/residential India Agra 4 DCM /GC-FID 40 - 2500 SPM Industrial India Delhi14 DCM /GC-MS 33.1- 81.5 PM10Roadside/residential India Tiruchirapalli15DCM: methanol/HPLC 232.7 PM2.5 Residential Hong kong Kwun Tong19 DCM / GC-FID 2- 269 PM10residential/industrial Taiwan Taichung 20 DCM /GC-MS 180.62 PM 2.5 Residential Greece Elefsina 21 Acetonitrile/HPLC 0.6- 38.3 PM 10 Industrial Turkey Zonguldak province22hexane - acetone/HPLC 28 PM10 Industrial Table-3 Seasonal variation of PAHs showing minimum (MIN), maximum (MAX) and average (AVG) concentrations and standard deviation (SD) of PAHs in ngm 3 in (a) winter, (b) summer, (c)monsoon seasons PAHs Summer Monsoon Winter Min Max Avg Sd Min Max Avg Sd Min Max Avg Sd Naph 1.2 3.9 2.1 0.7 1.0 3.4 2.0 0.9 3.3 6.3 4.7 0.8 Acy 9.9 15.8 12.3 1.8 7.4 11.4 9.3 1.3 12.5 18.5 15.8 1.8 Fluo 2.3 7.2 4.6 1.4 1.5 4.8 2.5 0.9 5.4 9.7 7.8 1.3 Ace+Phen 5.9 11.4 8.4 1.7 3.5 9.3 5.7 1.8 10.2 16.1 13.0 2.0 Anth 1.0 4.0 2.4 0.9 0.7 3.0 1.5 0.8 3.0 6.3 4.4 0.9 Flt 0.9 2.6 1.3 0.5 0.7 2.5 1.1 0.6 1.6 4.3 3.0 0.8 Pyr 0.9 4.0 2.0 1.2 0.6 3.1 1.3 0.9 3.6 10.8 7.4 1.9 Chry+BaA 0.9 2.7 1.4 0.5 0.6 3.7 1.3 1.0 1.3 5.9 3.8 1.3 BbF 0.7 1.9 1.2 0.4 0.3 2.6 0.9 0.7 2.0 5.9 3.7 1.2 BkF 0.6 2.9 1.1 0.5 0.3 2.1 0.9 0.7 3.5 6.7 5.0 0.9 Pery 0.3 2.9 1.0 0.8 0.2 1.0 0.4 0.2 1.0 3.9 2.1 0.9 BaP 0.2 2.9 1.5 0.7 0.5 2.5 1.0 0.6 1.3 3.5 2.5 0.7 IP 0.1 5.6 1.9 1.7 0.4 2.5 1.0 0.6 1.4 4.6 2.9 0.9 BghiP 3.0 7.2 4.8 1.1 2.6 8.3 5.1 1.6 5.7 17.7 13.0 3.5 Total 32.4 65.9 46.1 10.6 23.4 56.1 34.0 11.2 65.6 104.9 88.9 12.2 International Research Journal of Environment Vol. 3(11), 57-64, November (2014) International Science Congress Association Correlation of PAHs with PM10 and other meteorological parameters: The meteorological parameters, such as precipitation, temperature and relative humidity during 2010 and their correlations with TPAHs concentrations in PM displayed in table-4a and table- 4b. The correlation coeffi was calculated using Pearson Correlation Coefficient. TPAH concentration showed strong positive correlation with PM Strong negative correlation was observed between TPAH and the parameters like temperature and relative humidity. Moderate negative correlation was observed between TPAHs and precipitation. This suggests that, in ambient air the concentration of particulate matter and related PAHs generally decrease with increasing wind speed, rainfall and humidity Thus, it can be concluded that met eorological conditions Winter/Summer and winter/monsoon ratios of concentrations of PAHs at Visakhapatnam The meteorological parameters in Visakhapatnam in the year 2010 Min temp Max temp °C January 17 February 18.9 March 22 April 25.1 May 26.7 June 26.3 July 25.1 August 25 September 24.6 October 23.3 November 20.6 December 17.6 Correlation coefficients of TPAHs with meteorological parameters Parameters Correlation coefficients with TPAHs 0.001.002.003.004.005.006.00 Environment Sciences_______________ _________________________ International Science Congress Association and other meteorological The meteorological parameters, such as precipitation, temperature and relative humidity during 2010 and their correlations with TPAHs concentrations in PM 10 are 4b. The correlation coeffi cient was calculated using Pearson Correlation Coefficient. TPAH concentration showed strong positive correlation with PM 10. Strong negative correlation was observed between TPAH and the parameters like temperature and relative humidity. Moderate correlation was observed between TPAHs and precipitation. This suggests that, in ambient air the concentration of particulate matter and related PAHs generally decrease with increasing wind speed, rainfall and humidity 16. eorological conditions strongly affect the PAHs showing a seasonal variability in their concentrations. Potential sources of PAHs and study of Diagnostic ratios: many recent studies, the different PAH compounds were used as tracers to identify their d iverse sources. It was observed that B(k)F, B(ghi)P and IP can be the tracers for vehicular emissions while the particulate matter samples enriched in B(ghi)P and coronene are characteristic of gasoline engines and Anth, Phen, Flt, pyr were identified as t he tracers for wood combustion. Phen, Flt are characteristic of coal combustion while B(a)P, B(ghi)P are tracers for wood combustion and Pyr, B(ghi)p, B(b)F and B(k)F are the tracers for heavy Figure-3 Winter/Summer and winter/monsoon ratios of concentrations of PAHs at Visakhapatnam Table4a The meteorological parameters in Visakhapatnam in the year 2010 -11 Max temp Avg temp Precipitation °C °C mm 28.9 22.9 17.4 31.3 25.1 25.2 33.8 27.9 29 35.3 30.2 37.6 36.2 31.5 77.8 35.3 30.8 135.6 32.9 29 164.6 32.7 30 181.2 32.5 28.5 224.8 31.7 27.5 234.3 30.4 25.5 95.3 28.9 23.5 37.9 Table-4b Correlation coefficients of TPAHs with meteorological parameters Average temp precipitation Relative Humidity (°C) ( mm) ( %) -0.91 -0.68 - Winter/Summer ratio Winter/Monsoon ratio _________________________ ______ ISSN 2319–1414 Int. Res. J. Environment Sci. 61 strongly affect the PAHs showing a seasonal variability in their Potential sources of PAHs and study of Diagnostic ratios: In many recent studies, the different PAH compounds were used as iverse sources. It was observed that B(k)F, B(ghi)P and IP can be the tracers for vehicular emissions while the particulate matter samples enriched in B(ghi)P and coronene are characteristic of gasoline engines and Anth, Phen, he tracers for wood combustion. Phen, Flt are characteristic of coal combustion while B(a)P, B(ghi)P are tracers for wood combustion and Pyr, B(ghi)p, B(b)F and B(k)F are the tracers for heavy -duty diesel vehicles18. Winter/Summer and winter/monsoon ratios of concentrations of PAHs at Visakhapatnam Rel humidity % 70 72 75 76 77 74 76 77 78 74 68 64 Relative Humidity PM 10 ( %) (µgm - 3 ) - 0.87 0.81 Winter/Summer Winter/Monsoon International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 3(11), 57-64, November (2014) Int. Res. J. Environment Sci. International Science Congress Association 62 Along with this, for preliminary assessment of sources of PAHs, Molecular diagnostic ratios of PAHs which frequently found together are studied. There values are compared with values in published literature. In this study, the ratio IP/ (IP+B(ghi)P) showed value of 0.19 which is given for petrogenic source in literature19. Also value 0.64 was obtained for the Fluo/(Fluo+Pyr) ratio which shows coal combustion ranging between 0.46-0.7619. The ratio Ind/B(ghi)P had value 0.26, which indicates gasoline engine20. Further the B(b)F/B(k)F ratio was found to be 0.95 with a value �0.5 which is given for diesel emissions21. The value 0.41 was observed for ratio Flt/Flt+Pyrranged between 0.27-0.53 which attributes to gasoline emission22. Thus, the diagnostic ratio study shows that gasoline and diesel power vehicles and coal combustion are the main sources of PAHs in Vizag. Table-5 represents the diagnostic ratios for the PAHs in this study compared with literature values to attribute the specific sources. Potential Source identification using factor analysis: Factor analysis or Principal component analysis is a useful method for source identification of PAHs which is based on multivariate data analysis23. In this, large number of data set is reduced to small number of independent variables. For this study, the number of extracted principal components corresponds to the sources of PAHs. The analysis was carried out using SPSS software version 9. “Factor loadings” obtained after the varimax rotation give the correlation between the variables and the factors. Data were included in the matrix only if the Eigen value for the factor is greater than 1. Table-6 represents the results of PCA applied to data at study site. It represented five factors. The first factor was responsible for 51.89% of the total variance. It consists of high loadings of Naph (0.722), Ace+ Phen (0.832), Chry+B(a)A (0.814), B(b)F (0.511), B(a)P (0.699). This factor is indicative of coal combustion24,25. Second factor showed 16.11% of the overall variance. It was highly loaded with Acy (0.853), Fluo (0.883), B(b)F (0.534), Pery (0.583), B(a)P (0.449) and IP (0.426). This factor strongly indicates emission from gasoline vehicles14,18. The third factor was showing 7.6% of the total variance. This factor was strongly loaded with highly carcinogenic PAHs like Pyr (0.702), B(k)F (0.726), Pery (0.497) and B(ghi)P (0.868) which can be attributed to diesel powered vehicles as B(k)F is the tracer for diesel powered vehicular10,19,26. The forth factor showed 5.77% of the overall variance with high loadings of Flt (0.874) and IP (0.540). It could be identified as marker of combustion of lubricating oil18,27. Table-5 Diagnostic Ratios for the PAHs compared with literature values to attribute the specific sourcesDiagnostic ratios This Study range/mean in literature Source References Mean Range IP/ (IP+BghiP) 0.19 0.09-0.21 0.18-0.2 Petrogenic source 27 Fluo/ (Fluo+Pyr) 0.64 0.46-0.76 �0.5 Coal combustion 27 IP/BghiP 0.26 0.10-0.51 0.4 gasoline engine 28 BbF/BkF 0.95 0.6-1.4 �0.5 Diesel emission 29 Flt/Flt+Pyr 0.41 0.27-0.53 0.4 gasoline emission 30 Table-6 Results of PCA applied to concentrations of PAHs with varimax rotationPahs Factor 1 Factor 2 Factor 3 Factor 4 Factor 5 Naph 0.722 0.253 0.280 - 0.119 Acy - 0.853 0.190 0.182 0.273 Fluo 0.212 0.883 0.109 - - Ace+Phen 0.832 0.116 0.155 0.210 - Anth - 0.271 0.178 0.130 0.919 Flt 0.352 0.151 - 0.874 0.175 Pyr 0.467 0.229 0.702 - 0.179 Chry+BaA 0.814 - 0.380 0.236 - BbF 0.511 0.534 0.296 0.232 - BkF 0.281 0.424 0.726 0.199 0.149 Pery - 0.583 0.497 0.153 - BaP 0.699 0.459 0.147 0.139 - IP 0.407 0.657 0.330 0.540 0.230 BghiP 0.270 0.132 0.868 - - Variance (%) 51.89 16.11 7.60 5.77 5.09 Cumulative(%) 51.89 68.01 75.61 81.39 86.48 Source Coal combustion Gasoline emission Diesel emmision Lubricating oil burning Stationary sources Loading greater than 0.4 is considered International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 3(11), 57-64, November (2014) Int. Res. J. Environment Sci. International Science Congress Association 63 The fifth factor was responsible for 5.09% of the total variance. This factor was strongly loaded with Anth (0.919). Anth mainly indicates stationary sources like steel industry, power plant etc14,24. Thus the dominant sources of PAHs in the ambient air of Vizag were mainly coal combustion, diesel and gasoline powered vehicles, lubricating oil burnings and stationary sources like power plant and steel industry. Conclusion For the study, the concentrations of TPAHs varied between 23.4 and 104.9 ngm-3 with average concentration of 57ngm-3. The dominating PAHs were Acy, Ace, Phen, Pyr, B(ghi)P, B(a)P, and B(k)F. The two and three ring PAHs were predominant than four, five and six ring PAHs and contributed to about 56% of total PAHs. The potent six carcinogenic PAHs mentioned by IARC accounted for 18% of the total PAHs. The PAHs concentrations were found to be elevated in winter than summer and monsoon. The total PAHs concentration during winter was about twice than the concentrations in summer and about 2.6 times higher than the concentration in monsoon. The average W/S ratio for TPAH was 1.9 and that of the W/M ratio was 2.6. The inverse correlation between PAHs and temperature, relative humidity and rainfall suggested that these meteorological conditions strongly affect the PAHs concentrations. Molecular diagnostic ratios and principal component analysis (PCA) studies of the data indicated that coal combustion, diesel and gasoline powered vehicular emissions, lubricating oil burning and stationary sources from steel plant were the major sources of PAHs at study site. Coal combustion and stationary sources are signatures of thermal power plant and steel industry. The reason for such a high concentration of PAHs in the ambient air of Vizag can be the increased vehicular traffic and use of fossil fuels due to growth in human population. 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