Source characterization and health risks of BTEX in indoor/outdoor air during winters at a terai precinct of North India.

BTEX are the consistently found air contaminants in indoor and outdoor environments. In order to investigate the exposure levels of BTEX, the indoor and outdoor air was analyzed during winter season at homes located at four selected sites of Gorakhpur, Uttar Pradesh, India, which comprised residential, roadside, industrial and agricultural areas. BTEX were sampled with a low-flow pump (SKC model 220). Samples were extracted with CS2 and the aromatic fraction was subjected to GC-FID. Mean indoor concentration of BTEX was highest at the agricultural (70.9 µg m-3) followed by industrial (30.0 µg m-3), roadside (17.5 µg m-3) and residential site (11.8 µg m-3). At outdoor locations, the mean BTEX levels were highest at the roadside (22.0 µg m-3) followed by industrial (18.7 µg m-3), agricultural (11.0 µg m-3) and residential site (9.1 µg m-3). The I/O ratios were greater than 1 at all the sites except roadside site, where I/O ratios for toluene, ethylbenzene and xylene were less than unity. Poor correlation between indoor and outdoor levels at each site further indicated the dominance of indoor sources. Factor analysis followed by one-way analysis of variance depicts that the presence of BTEX compounds at all the sites indicate a mixture of vehicular and combustion activities. For benzene, the ILTCR values exceeded the safe levels, whereas ethylbenzene was nearby to the recommended level 1 × 10-6. The HQ values were above unity for agricultural (indoors) and industrial (outdoors) as an exception to all the other sites which indicted the value below unity.

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.

Study of air-soil exchange of polycyclic aromatic hydrocarbons (PAHs) in the north-central part of India--a semi arid region.

Soil is the major environmental reservoir of organic compounds and soil-air exchange is a key process in governing the environmental fate of these compounds on a regional and global scale. Samples of air and soil were collected to study the levels of PAHs in the air and soil of the Agra region. Concentrations of PAH measured at four locations in the city of Agra, covers industrial, residential, roadside and agricultural areas. Samples were extracted with hexane by ultrasonic agitation. Extracts were then fractioned on a silica-gel column and the aromatic fraction was analysed by GC-MS. The mean concentration of the total PAH (T-PAH) in the air of Agra was 24.95, 17.95 and 14.25 ng m(-3), during winter, monsoon and summer respectively. The average concentration of T-PAH in the soil of Agra was 12.50, 8.25 and 6.44 µg g(-1) in winter, monsoon and summer seasons respectively. The aim of this study was to investigate the rate of approach to equilibrium partitioning of PAHs between air and soil compartments and to determine the direction of net flux of the studied PAH between air and soil. Calculated soil-air fugacity quotients indicate that the soil may now be a source of some lighter weight PAHs to the atmosphere, whereas it appears to be still acting as a long-term sink for the heavier weight PAHs to some extent in this region.

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.

Diffusion-weighted imaging: not all that glitters is gold.

Diffusion-weighted imaging (DWI) is a sophisticated magnetic resonance imaging (MRI) technique with rapid acquisition time and high sensitivity for depicting acute cerebral ischemia. It is currently part of the routine workup in most medical centers when ischemic stroke is in the differential diagnosis. DWI helps establish a diagnosis of acute ischemic infarct even in cases where the clinical presentation is not typical for ischemic stroke. However, contrary to popular belief, not every hyperintensity on DWI is an ischemic stroke. Consequently, DWI with high intensity signals, commonly called "positive" DWI, is sometimes misinterpreted and leads to incorrect medical management. In this report, we briefly discuss some of the essential, technical aspects of DWI and report various clinical scenarios, which may lead to "positive" DWI findings but are not ischemic strokes. Although the sensitivity of DWI for ischemic stroke is very high, the specificity is not as high, and a "positive" DWI does not exclude other diagnoses that should be considered based on each patient's clinical history and examination, and the appearance of other sequences of MRI scans.

Indoor air quality of houses located in the urban environment of Agra, India.

Increased concern over the adverse health effects of air pollution has highlighted the need for air-pollution measurements, especially in urban areas, where many sources of air pollutants are normally monitored outdoors as part of obligations under the National Air Quality Strategies. Very little is known about air pollution indoors. In fact, the largest exposure to health-damaging indoor pollution probably occurs in the developing world, not in households, schools, and offices of developed countries where most research and control efforts have been focused to date. As a result much of the health impacts from air pollution worldwide seem to occur among the poorest and most vulnerable populations. The authors in their earlier studies have confirmed the importance of ambient air in determining the quality of air indoors. In this study an observation of air quality indoors and outdoors of domestic homes located in an urban environment from October 2004 to December 2005 in Agra, north central India, is performed. The purpose of this study was to characterize the indoor/outdoor (I/O) relationship of airborne pollutants and recognize their probable source in all three seasons, that is, winter, summer, and rainy season. Concentrations of SO(2), NO(2), CO(2), Cl(2), H(2)S, NH(3), RSPM, and PAH were monitored simultaneously and I/O ratios were calculated. In order to investigate the effect of seasonality on indoor and ambient air quality, winter to summer and winter to monsoon average ratios were calculated. It is apparent that there is a general pattern of increasing levels from monsoon to summer to winter, and similarly from outdoor to indoor air. Regressions analysis had been done to further investigate the influence of outdoor air-pollutant concentrations on indoor concentrations. The most probable categories of sources for these pollutants have been identified by using principal-component analysis. Indoor air pollution is a complex function of energy housing and behavioral factors. On the basis of this study and observations, some interventions are also suggested.

Treatment of extracranial carotid artery pseudoaneurysms with stent grafts: case series.

BACKGROUND AND PURPOSE: Extracranial carotid artery pseudoaneurysms are a rare entity with a poorly defined natural history. Treatment has been limited to open surgical repair and limited experience with endovascular repair. We review our experience with the use of stent grafts to treat this disease entity. METHOD: We retrospectively reviewed the interventional databases of two university hospitals (Michigan State University and University of Pittsburgh Medical Center) between 2004 and 2006 to identify patients with carotid pseudoaneurysms that were treated with stent grafts. A total of five patients were identified. RESULTS: Of the five patients treated, four presented with acute bleeding secondary to carcinomatous invasion of the carotid artery, while one presented with thromboembolic events. Four of the five were successfully occluded with stent grafts. The one patient in whom the bleeding could not be stopped with the stent graft expired due to cardiac arrest. There were no peri-procedural complications noted as a result of stent graft placement. CONCLUSIONS: Stent grafts can be utilized to treat pseudoaneurysms safely, but may not always stop active extravasation as an isolated therapy. Long-term data is required to determine the durability of the treatment.

Polycyclic aromatic hydrocarbons (PAHs) concentrations and related carcinogenic potencies in soil at a semi-arid region of India.

A study of polycyclic aromatic hydrocarbons in surface soil was conducted at selected locations in Agra (semi-arid region of India) for a span of one year in order to ascertain the contamination levels. The concentrations of PAH were measured at four locations in the city of Agra, which covers industrial, residential, roadside and agricultural areas. The samples were extracted with hexane by ultrasonic agitation. The extracts were then fractioned on a silica-gel column and the aromatic fraction was subjected to HPLC. The average concentration of total PAH in all samples was 12.1 microg g(-1) and the range was from 3.1 microg g(-1) to 28.5 microg g(-1). The maximum concentrations of PAHs were found to be in winter season. The concentration of PAH decreased in the order chrysene > benzo(b)fluoranthene > fluoranthene. Factor analysis suggests that the mixed signature of all the sources are intermediate between vehicular and combustion activities.

Investigation of polycyclic aromatic hydrocarbons (PAHs) in soil at Agra, India--a case study.

Polycyclic Aromatic Hydrocarbons (PAHs) are released into the environment from anthropogenic sources, such as combustion of fossil fuels, refused burning, industrial processes and motor vehicle exhausts. The concentration of PAHs in roadside soil was measured at St. John's crossing, which lies in the centre of Agra city and exposed to heavy traffic. The samples were extracted with hexane by ultrasonic agitation. The extracts were then fractioned on a silica-gel column and the aromatic fraction was subjected to HPLC for analysis of 16 priority PAH pollutants specified by environment protection agency (EPA). Total mean concentration of PAHs was found to be 15.29 microg g(-1) and it ranged from 6.72-25.91 microg g(-1). Fluoranthene, chrysene, benzo(b)fluoranthene and benzo(ghi)perylene were found to be the most abundant PAHs at this location.