Concentration and sources of fine particulate associated polycyclic aromatic hydrocarbons at two locations in the western coast of India.

PM2.5 particulate matter (PM) and their associated polycyclic aromatic hydrocarbons (PAHs) were studied at Urban and Sub-urban sites in the western coast of India. The concentration of PM2.5 ranged from 66.29 µg m-3 to 182.15 µg m-3, being the highest at Sub-urban site than the urban site. There were total six carcinogenic PAHs found to be dominated in particulate samples at these locations. The general trends observed for individual carcinogenic PAHs concentration at urban location was, benzo(a)pyrene (BaP)

Exposure levels and health risk assessment of ambient BTX at urban and rural environments of a terai region of northern India.

Benzene, toluene and xylene (BTX) belong to an important group of aromatic volatile organic compounds (VOCs) that are usually emitted from various sources. BTX play a vital role in the tropospheric chemistry as well as pose health hazard to human beings. Thus, an investigation of ambient benzene, toluene and xylene (BTX) was conducted at urban and rural sites of Gorakhpur for a span of one year in order to ascertain the contamination levels. The sampling of BTX was performed by using a low-flow SKC Model 220 sampling pump equipped with activated coconut shell charcoal tubes with a flow rate of 250 ml/min for 20-24 h. The analysis was in accordance with NIOSH method 1501. The efficiency of pump was checked weekly using regulated rotameters with an accuracy of ±1%. The samples were extracted with CS2 with occasional agitation and analyzed by GC-FID. The total BTX concentration ranged from 3.4 µg m-3 to 45.4 µg m-3 with mean value 30.95 µg m-3 and median 24.8 µg m-3. The mean concentration of total BTX was maximum during winter (39.3 µg m-3), followed by summer (28.4 µg m-3) and monsoon season (25.1 µg m-3). The mean concentration of BTX at urban site (11.8 µg m-3) was higher than that at rural site (8.8 µg m-3). At both the sites, T/B and X/B ratios were highest in monsoon and lowest in winters. Toluene against benzene plot shows R2 value of 0.96 and 0.49 at urban and rural sites respectively. Higher R2 value at urban site clearly indicates similar sources of emission for benzene and toluene. At both the sites, the estimated integrated lifetime cancer risk (ILTCR) for benzene exceeded the threshold value of 1E-06 whereas the individual hazard quotients (HQ) for BTX did not exceed unity at any of the sites.

Exposure profiles, seasonal variation and health risk assessment of BTEX in indoor air of homes at different microenvironments of a terai province of northern India.

BTEX are known for their ability to deteriorate human health. A monitoring study was conducted at Gorakhpur, for a span of one year. BTEX were sampled by drawing air through activated charcoal tubes, using a low flow SKC model 220 pump. Samples were extracted with CS2 followed by subjecting the aromatic fraction to GC-FID. The mean concentration of BTEX was highest at agricultural (54.3 µg m-3) followed by industrial (18.2 µg m-3), roadside (12.3 µg m-3) and residential site (6.1 µg m-3). Toluene levels were higher than benzene at all the sites except agricultural site, where benzene concentration exceeded toluene. Seasonal variation showed highest BTEX concentration during winters (32.56 µg m-3) followed by monsoon (19.90 µg m-3) and summers (14.44 µg m-3). At each site, BTEX levels increased with decrease in temperature. Benzene and toluene levels were plotted against indoor temperature, which revealed a significant linear correlation (p < 0.001) for each plot. BTEX concentrations were compared between different sites using Student's t and Mann Whitney U tests. Value of integrated lifetime cancer risk (ILTCR) was higher than 10-6 for benzene at all the sites, while for ethylbenzene, it was only higher at agricultural site. Cumulative hazard index (HI) was lower than 1.0 at all the sites.

Exposure profiles of mercury in human hair at a terai belt of North India.

Human hair is frequently used as a bioindicator of mercury exposure. Mercury (Hg) has for centuries been a useful metal in a variety of applications. Unfortunately, this usefulness is counterbalanced by its neurotoxicological health impact. The US Environmental Protection Agency recommends keeping the hair Hg level <1.0 µg/g. Therefore, an investigation has been performed in order to ascertain the hair Hg levels among the people living at the terai belt of North India. Hair samples were collected from 111 individuals and were placed in an identified plastic bag, stapled to prevent the shift of the hair strand. Samples were analyzed by combustion, gold amalgamation, atomic absorption spectrometry (C-GA-AAS). The mean Hg level in hair was 0.28 µg/g for the whole group ranging from 0.0012 to 1.9091 µg/g. The mean hair Hg levels were 0.16 µg/g for men and 0.12 µg/g for women, indicating that men had higher hair Hg levels than women. Total hair Hg was found to be significantly associated with age, gender and fish consumption frequency. 98 % of the total sample had hair Hg concentrations less than 1.0 µg/g, i.e, within safe dose, whereas only 2 % had Hg concentrations greater than 1.0 µg/g, thereby exceeding the safe dose.

Characteristics of polycyclic aromatic hydrocarbons in indoor and outdoor atmosphere in the North central part of India.

Twenty-three polycyclic aromatic hydrocarbons (PAHs) were measured simultaneously in indoor and outdoor environment of ten homes at urban and roadside sites in the north central part of India during winter season (November 2006 to February 2007). The average concentration of total PAH (TPAH) was 1946.84 ng/m(3) in kitchen, 1666.78 ng/m(3) in living room and 1212.57 ng/m(3) in outdoors at urban site, whereas at roadside site it was 2824.87 ng/m(3), 2161.26 ng/m(3)(,) and 3294.28 ng/m(3) in kitchen, living room and outdoors respectively. The two, three and four ring PAHs were predominant in vapour phase, while the five, six ring PAHs were primarily associated with the particulate phase. The concentration trends of the PAHs in present study were naphthalene>2-methylnaphthalene>1-methylnaphthalene>biphenyl>acenaphthylene in indoor and outdoor environment of both the sites. The spatial trend of total PAHs concentrations in the house located at urban sites, was kitchen>living room>outdoors whereas at roadside site, the trend was outdoors>kitchen>living room. Correlation analysis has been used to identify the sources of PAHs. The correlation between CO(2) and ratio of living room/outdoors (L/O) and kitchen/outdoor (K/O) of total PAHs concentration for two sites was found to be significant.

Concentrations, sources, and exposure profiles of polycyclic aromatic hydrocarbons (PAHs) in particulate matter (PM(10)) in the north central part of India.

Airborne particulates (PM(10)) from four different areas within Agra city (a semi-arid region) were collected using respirable dust samplers during the winter season (Nov. 2005-Feb 2006) and were then extracted with methylene chloride using an automated Soxhlet Extraction System (Soxtherm). The extracts were analyzed for 17 target polycyclic aromatic hydrocarbons (PAHs) and the heterocycle carbazole. The average concentration of total PAH (TPAH) ranged from 8.04 to 97.93 ng m(-3). The industrial site had the highest TPAH concentration followed by the residential, roadside, and agricultural sites. Indeno(1,2,3-cd)pyrene, benzo(g,h,i)perylene, and benzo(b)fluoranthene were the predominant compounds found in the samples collected from all of the sites. The average B(a)P-equivalent exposure, calculated by using toxic equivalent factors derived from literature and the USEPA, was approximately 7.6 ng m(-3). Source identification using factor analysis identified prominent three, four, four, and four probable factors at industrial, residential, roadside, and agricultural sites, respectively.