Dipanjali Majumdar

Volatile organic compound emissions from municipal solid waste disposal sites: A case study of Mumbai, India

Improper solid waste management leads to aesthetic and environmental problems. Emission of volatile organic compounds (VOCs) is one of the problems from uncontrolled dumpsite. VOCs are well known to be hazardous to human health and many of them are known or potential carcinogens. They also contribute to ozone formation at ground level and climate change as well. The qualitative and quantitative analysis of VOCs emitting from two municipal waste (MSW) disposal sites in Mumbai, India, namely Deonar and Malad, are presented in this paper. Air at dumpsites was sampled and analyzed on gas chromatography–mass spectrometry (GC-MS) in accordance with U.S. Environmental Protection Agency (EPA) TO-17 compendium method for analysis of toxic compounds. As many as 64 VOCs were qualitatively identified, among which 13 are listed under Hazardous Air Pollutants (HAPs). Study of environmental distribution of a few major VOCs indicates that although air is the principal compartment of residence, they also get considerably partitioned in soil and vegetation. The CO2 equivalent of target VOCs from the landfills in Malad and Deonar shows that the total yearly emissions are 7.89E+03 and 8.08E+02 kg, respectively. The total per hour ozone production from major VOCs was found to be 5.34E-01 ppb in Deonar and 9.55E-02 ppb in Malad. The total carcinogenic risk for the workers in the dumpsite considering all target HAPs are calculated to be 275 persons in 1 million in Deonar and 139 persons in 1 million in Malad. Implications: This paper describes the hazards of VOC emission from open dumpsites, a common practice, in an Indian metro city. The subsequent partitioning of the emitted VOCs in other environmental compartment from air is presented. The global warming potential and the health hazards to the dumpsite workers from the emitted VOCs have also been estimated.

Emission, speciation, and evaluation of impacts of non-methane volatile organic compounds from open dump site

Surface emission from Dhapa, the only garbage disposal ground in Kolkata, is a matter of concern to the local environment and also fuels the issues of occupational and environmental health. Surface emission of the Dhapa landfill site was studied using a flux chamber measurement for nonmethane volatile organic compounds (NMVOCs). Eighteen noncarbonyl volatile organic compounds (VOCs) and 14 carbonyl VOCs, including suspected and known carcinogens, were found in appreciable concentrations. The concentrations of the target species in the flux chamber were found to be significantly higher for most of the species in summer than winter. Surface emission rate of landfill gas was estimated by using two different approaches to assess the applicability for an open landfill site. It was found that the emissions predicted using the model Land GEM version 3.02 is one to two orders less than the emission rate calculated from flux chamber measurement for the target species. Tropospheric ozone formation has a serious impact for NMVOC emission. The total ozone-forming potential (OFP) of the Dhapa dumping ground considering all target NMVOCs was estimated to be 4.9E+04 and 1.2E+05 g/day in winter and summer, respectively. Also, it was found that carbonyl VOCs play a more important role than noncarbonyl VOCs for tropospheric ozone formation. Cumulative cancer risk estimated for all the carcinogenic species was found to be 2792 for 1 million population, while the total noncancer hazard index (HI) was estimated to be 246 for the occupational exposure to different compounds from surface emission to the dump-site workers at Dhapa. Implications: This paper describes the real-time surface emission of NMVOCs from an open municipal solid waste (MSW) dump site studied using a flux chamber. Our study findings indicate that while planning for new landfill site in tropical meteorology, real-time emission data must be considered, rather than relying on modeled data. The formation of tropospheric ozone from emitted NMVOC has also been studied. Our result shows how an open landfill site acts as a source and adds to the tropospheric ozone for the airshed of a metropolitan city.

Emission inventory of evaporative emissions of VOCs in four metro cities in India

High concentrations of volatile organic compounds (VOCs) in ambient air of urban areas stress the need for the control of VOC emissions due to the toxic and carcinogenic nature of many VOCs commonly encountered in urban air. Emission inventories are an essential tool in the management of local air quality, which provide a listing of sources of air pollutant emissions within a specific area over a specified period of time. This study intended to provide a level IV emission inventory as par the United States Environmental Protection Agency (USEPA) definition for evaporative VOC emissions in the metro cities of India namely Delhi, Mumbai, Chennai, and Kolkata. The vehicular evaporative emissions are found to be the largest contributor to the total evaporative emissions of hydrocarbons followed by evaporative losses related to petrol loading and unloading activities. Besides vehicle-related activities, other major sources contributing to evaporative emissions of hydrocarbons are surface coating, dry cleaning, graphical art applications, printing (newspaper and computer), and the use of consumer products. Various specific preventive measures are also recommended for reducing the emissions.

Variability of BTEX in Residential Indoor Air of Kolkata Metropolitan City

Mono-aromatic hydrocarbons, namely benzene, toluene, ethylbenzene and isomers of xylene (BTEX) were studied within a group of typical urban residences. The average residential indoor levels of BTEX were 42.0, 69.3, 22.8, 52.1 and 21.6 µg·m−3, respectively. The indoor level was found to be significantly dependent on the type of fuel used and extent of ventilation but not on location of the residence or kitchen placement inside the residence. The average indoor/outdoor concentration ratio observed for BTEX > 1; and this indicates the presence of indoor sources for these compounds along with infiltration of outdoor air. The relative variability of the target compounds reveals that indoor sources, other than domestic fuel, like consumer products, cooking, etc., contribute significantly for xylenes and least for benzene. Also with increasing ventilation, the intrusion of outdoor air has definite contribution in increasing the indoor level in descending order for benzene, toluene, m-, p-xylene and ethylbenzene. For o-xylene, a removal effect was observed with increasing rate of ventilation. The human health risk estimation reveals that the average integrated lifetime cancer risk considering the exposure to benzene and ethylbenzene due to residing for only 15 years in such indoor conditions is 2.9 E−05, which is sufficiently higher than the acceptable risk of 1.0 E−06.

Effects of unregulated anthropogenic activities on mixing ratios of volatile organic air pollutants—A case study

During the months of October to November, many important festivals are celebrated in India. Celebration of these festivals are marked by extensive use of fireworks or pyrotechnics, bonfire, incense burning, open air community cooking, and temporary eateries using crude fuel such as coal, wood, kerosene, cow dung, burning of raw/semiwood, and coconut shells. The present study deals with the influence of these unregulated anthropogenic activities on ambient mixing level of volatile organic compounds (VOCs), especially some carbonyl compounds. The study was undertaken in the metropolitan city of Kolkata, India, with very high population density, which is even higher during festival period. The average total carbonyl level at different sites in Kolkata varied from 134.8 to 516.5 μg m−3 in pre-festival season, whereas in post-festival season the same varied from 252.2 to 589.3 μg m−3. Formaldehyde to acetaldehyde ratio altered from 0.62 in pre-festival season to 1.78 in post-festival season. Diurnal variation also altered, indicating variation in source composition of carbonyls. The total ozone forming potential calculated for all 14 carbonyls in pre-festival season increased by 35% in post-festival season. The effect of anthropogenic activities typical to the event of Diwali night characterized by intense execution of pyrotechnics resulted in significantly high level of carbonyl VOCs. Principal component analysis study for the event of Diwali shows clear contribution of the event on certain carbonyl VOCs. The results indicate elevated primary emissions of these pollutants and also their effect on formation of secondary pollutants. The study emphasizes the need of generating awareness among the communities in society as well as need for regulations to minimize the emissions and related hazards to the extent possible. Implications: Altered anthropogenic activities typical of festival season including extensive use of pyrotechnics affect ambient level of volatile organic compounds, especially some carbonyls. Such activities have considerable effect on interspecies ratio and diurnal variation. They also affect formation of secondary pollutants such as tropospheric ozone. Principal component analysis (PCA) study shows clear contribution of the pyrotechnics execution on certain carbonyl VOCs. The findings emphasize the need of generating awareness in society and need for regulations to minimize the emissions.

Free iron status & insulin resistance in type 2 diabetes mellitus: Analyzing the probable role of a peanut protein.

Sir, South Asian population is known to have an increased predisposition to type 2 diabetes mellitus (T2DM), which turns out to be an important health concern in this Region1. As per an earlier report about 11.7 per cent people of Kolkata, West Bengal, suffered from T2DM and the prevalence was on a rise2. Anaemia is also present in the Region as a significant public health problem, having a prevalence of greater than 40 per cent in South Asia3. However, the actual status of iron remains unclear because of extensive prevalence of haemoglobinopathies, possible genetic mutations contributing to iron overload, indiscriminate over-the-counter use of iron pills and traditional formulations containing undefined concentrations of iron. Higher heme iron intake and increased body iron stores were found to be significantly associated with a greater risk of T2DM4,5. Patients suffering from haemoglobinopathies or undergoing repeated blood transfusions also suffer from secondary iron loading disorder6. Insulin influences the iron uptake and storage in cells by increasing the cell surface transferrin receptors7. Whether a patient with diabetes has excess iron due to increased insulin resistance still remains an unanswered question. Insulin resistance has been shown to have an association with chronic kidney diseases8,9. Iron accumulation has been reported in the proximal renal tubules in diabetic nephropathy10. Iron in its free form11,12 i.e. in non-transferrin bound form is known to induce oxidation of biomolecules and in the formation of reactive oxygen species. We, therefore, studied the free iron status in patients with T2DM and compared with healthy individuals and to find a suitable biocompatible reagent which can bind the free iron. A cross-sectional, pilot study was conducted on consecutive patients attending the General Medicine outpatients department of M.R. Bangur Hospital, Kolkata, India, between August 2012 and February 2014. Fasting blood and urine samples (10 ml each) were collected from 111 patients with T2DM (53.7 ± 12.4 yr, M:F 60: 51) and 30 healthy controls (75.6 ± 2.5 yr, M:F 8:7). Approval of ethical committee of Institute of Post Graduate Medical Education & Research (IPGMER), Kolkata, was obtained prior to the study. Those (i) having anaemia, (ii) suffering from any form of haemoglobinopathy, (iii) who were on iron therapy within one year, (iv) having non-diabetic kidney disease, (v) having febrile illness, (vi) having benign prostatic hypertrophy or prostatic cancer, (vii) having urinary tract infection, or (viii) with uncontrolled hypertension, were excluded. The total iron analysis was done by Ferrozine method13 and free iron by HPLC14. Fasting plasma glucose was estimated by glucose oxidase-peroxidase (GOD-POD) method15, serum insulin by ELISA monobind kit and creatinine analysis was done by a kinetic assay15 of Jaffes involving alkaline solution of sodium picrate16. The plasma creatinine clearance or estimated glomerular filtration rate (eGFR) were estimated as per Cockroft and Gault formulae in ml/min17. Insulin resistance was calculated by homeostatic model assessment - insulin resistance (HOMA-IR) formula18. Urinary microalbumin analysis was done by immunoturbidimetry19. Conarachin I was extracted from peanut and purified20, and was used as a complexing agent for free iron. Conarachin I was characterized by molecular weight determination and absorption spectrometry20. A 15 per cent resolving sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) gel was used for molecular weight determination and confirmation of protein purification from crude peanut protein20. Presence of band at about 18 kD (Figure, lane 1) showed the presence of conarachin I in the purified protein fraction as shown earlier19. Conarachin I (0.1 ml) was mixed with 0.4 ml of the diluted serum, injected to HPLC column and analyzed to compare the amount of free Fe2+ and Fe3+ of the same serum samples20. Figure Purified conarachin I fraction along with its precursors subjected to sodium dodecyl sulphate - polyacrylamide gel electrophoresis (SDS-PAGE). Lane 1, pure conarachin 1; Lanes 2 and 3, protein part before purification; Lane 4, mol.wt.marker. Qualitative data were grouped and compared by chi square test. Yates correction was done when the cell frequency was below five21. Quantitative data were subjected to comparison by their differences in mean by unpaired t test. A HOMA value of 2.4 was taken as comparator as the value exhibited evidence of diabetic kidney disease in an Indian study22. Serum iron value of 150 µg/dl was taken as upper reference limit for both sexes considering 145 and 160 as upper reference limit (URL) for females and males, respectively as per the kit insert. Insulin resistance was not found to be significantly associated with total iron. Serum total iron values 150 µg/dl were compared with HOMA values 2.4 for both sexes. No association was seen when the means of total free iron were compared with HOMA 2.4 (15.7±1.64 vs16.02±2.56 ppm); insulin resistance was not related to Fe3+/Fe2+ ratio either in males or in females. Obesity, as body mass index (BMI in kg/m2) >2523 was compared with HOMA, the association was significant at (P<0.01). Free iron has been known to cause damage by generation of free radicals. As obesity with raised amount of adipose tissue contributes to more serum iron and serum iron is known to contribute to insulin resistance, we decided to multiply the BMI with the ferric-ferrous ratio, and took the product (BMI×Fe3+/Fe2+) as the index value. The median value of the distribution was around 0.37, the mode was 0.3, and HOMA was compared with values above and below 0.3 in females and males. Iron contributes to insulin resistance (IR) by hindering its action on liver. It also retards the catabolism of insulin leading to hyperinsulinaemia. Insulin contributes to iron overload by generating more transferrin receptors, more ferritin and entry of iron into the fat cells24. So with more number of fat cells, more iron will be present in the body. This will contribute to insulin resistance. A significant difference was obtained in females (P<0.001) but not in males when the index was compared to HOMA of 2.4. Also, concordance of our index values between females and males showed significance (P<0.001) (Table I). Thus, one can assume that the product of free iron ratios and BMI bears a stronger association with IR in females than in males or BMI alone. A mean free iron value of 15.82±1.38 ppm (n=111) was found in patients with diabetes, whereas it was 9.28±1.21 ppm in healthy controls (n=30) (P<0.001). Table I Comparison of sex concordance to index The stronger relationship with the index in females may be due to lesser amount of iron stores in them25. Ferric form contributes more to IR possibly as the origin of free iron is supposed to be from transferrin which contains iron in its ferric form. Ferric form may represent the initial active redox state of iron before being reduced to ferrous form. This led us to hypothesize that with more iron in ferric form, there would be more free iron turnover and hence more damage. Though higher amounts of both free and total iron were found amongst patients with microalbuminuria and lower eGFR, the results were not significant in our population which may be due to the presence of lesser amount of nephropathy in patients. Free iron was considerably reduced in the serum of most patients with diabetes upon addition of conarachin I with a few showing increase whereas serum samples of healthy subjects showed increase in the free iron concentration upon addition of conarachin I. The difference between the two groups was significant (P<0.001) (Table II). Patients with diabetes (mean fasting plasma glucose = 164.77±16.84 mg/dl) had a higher level of free iron than healthy individuals possibly due to more generation of non-transferrin bound iron (NTBI) by glycation of apotransferrin which does not bind iron avidly26. It was interesting to observe that the higher plasma glucose level in patients with diabetes renders the medium reducing so as the initial Fe3+/Fe2+ equilibrium in plasma is maintained even after being exposed to aerial oxidation for up to 72 h27. The serum of patients with diabetes having higher mean fasting plasma glucose levels might enhance the complexing ability of conarachin I and reduce the free iron level. In healthy controls with normal glucose levels, addition of the protein conarachin I from outside probably disturbs the equilibrium of transferrin bound iron and releases some bound iron free thus increasing the free iron level. The results indicate that peanut proteins may serve to design therapeutics to reduce excess free iron in patients with diabetes and hence control sugar levels especially in insulin resistant female patients. Table II Comparison between effect of conarachin I in serum of patients with and without diabetes In conclusion, free iron was significantly raised in serum of patients with T2DM when compared with healthy subjects. The calculated index of the product of BMI with the ferric-ferrous ratio may be important in assessing insulin resistance, particularly in females or BMI at any level of glycaemia. A peanut protein, conarachin I binds with the free iron in the serum of patients with diabetes and may contribute to the reduction of insulin resistance. The limitation of the study was that serum ferritin and total iron binding capacity (TIBC) were not measured. As serum ferritin is falsely raised in inflammatory states, thus may contribute as a confounding factor. The use of peanut protein to bind serum free iron is a subject of further investigations in animal models.

Air Pollution from Municipal Solid Waste Management Techniques

The rapid development of cities, increasing population and improper disposal of municipal solid waste (MSW) leads to human and environmental problem. Emission of various harmful inorganic and organic gaseous pollutants are unavoidable even when scientific methods of waste management are followed. The present study was undertaken to compare the ambient air quality at different types of solid waste management sites adopting different processes such as composting, mechanical waste management, open dumping, sanitary landfill. The study focused to assess the air quality with respect to a few selected inorganic gaseous pollutants and non-methane volatile organic compounds (NMVOCs) emitting from five municipal solid waste disposal sites within Kolkata metropolitan area (KMA) which adopt different management techniques. Air sample was collected by low-volume sampler and analysed according to CPCB standard methods and USEPA TO-17 methods for inorganic gases and NMVOCs, respectively. The study suggests that there are variations in pollutant emission across different waste management techniques. However, other local sources such as vehicular emission, residential emission also contribute to ambient level near management sites. Hence, to determine the contribution of the various waste management processes detailed sources apportionment study is required.

Distribution of Ozone over Urban Kolkata: Observed vs. UAM-V Prediction

Vehicular pollution, emissions due to burning of fossil fuel from industries and nonpoint sources in Kolkata are major sources of air pollution characterized by oxides of Nitrogen (NOx) and volatile organic compounds (VOCs). These pollutants are also responsible for the secondary ozone formation based on their reactivities. In the present study ozone has been monitored hourly every month in residential, industrial, traffic intersections, and petrol pumps in the urban area of Kolkata along with eight hourly nonoxygenated VOCs, carbonyls and NOx. Urban Airshed Model (UAM-V) has been used to simulate ozone on January 14, 2008 in Kolkata’s urban Area. Results of predicted ground level ozone have been in agreement with observed ozone concentrations.