Carcinogenic Polyaromatic Hydrocarbons Research Articles

Polycyclic aromatic hydrocarbons in citrus fruit irrigated with fresh water under arid conditions: Concentrations, sources, and risk assessment

• PAHs in citrus fruits grown in North of Deir-Alla, Jordan valley were investigated. • Grapefruits showed the highest ∑PAHs concentration (34.857 µg kg −1 ) • The ILCR in the study region indicated a potential cancer risks to population. • PAHs emission sources are biomass burning, vehicular emissions and petrogenic origin. • BCF for ∑16 PAHs was observed in the order of grapefruit > lemon > mandarin > orange. In Jordan, as well as in all the world countries, consumption of citrus fruits is an essential part of the daily diet, so it is important to assess the potential risk of the persistent organic pollutants such as polyaromatic hydrocarbons (PAHs) in these fruits to the human health and identify their sources in order to eliminate or reduce them. This study reports 16 priority PAHs content in four types of peeled citrus fruits grown in Jordan valley. PAHs were detected in all the studied samples in variable quantities depending on the type of citrus fruits. The results showed that the highest PAH level corresponded to acenaphthene (35.018 µg/kg) in grapefruit. Among the carcinogenic PAHs, benzo[a]anthracene (BaA) and benzo(a)pyrene (BaP) were the most representative and found in all the analyzed fruit, soil, and water samples, whereas anthracene (ANT) was not detected at all. The mean ∑16 PAHs for the different fruits were found to be 62.593 µg kg −1 in grapefruit, 24.840 µg kg −1 in lemon, 22.901 µg kg −1 in mandarin, and 5.082 µg kg −1 in orange. The dominance of naphthalene (NAP) and acenaphthene (ACE) in soil under hot climatic conditions indicates the recent and continuous input of these types in the investigated area. The bioconcentration factor (BCF) for ∑16 PAHs was observed in the order of grapefruit > lemon > mandarin > orange. Based on the results of the principal component analysis (PCA), the primary sources of PAHs in agricultural soils mainly originated from biomass burning and vehicular emissions. The incremental lifetime cancer risk (ILCR) indicated that consumption of these four citrus fruits may expose human health to potential cancer risk. The findings of this study call the policymakers and public administrations to the formulation of stringent policies and actions to control biomass burning and vehicular emissions.

Evaluation of Carcinogenic Polyaromatic Hydrocarbon Levels in Airborne Particulates Associated with Long-Term Exposure throughout the COVID-19 Pandemic in Makkah, Saudi Arabia.

Background: The effect of polyaromatic hydrocarbons (PAHs) on human health differs depending on the duration and exposure path. Objective: This study aimed to examine the effects of PAHs on the human health risks associated with long-term exposure both before and throughout the COVID-19 pandemic. Methodology: PM10 sampling for 24 h was conducted at six sampling sites (Al-Haram, Aziziyah, Al Nuzhah, Muzdalifah, Arafat, and Al Awali). On-site measurements were conducted from March 2020 to February 2021. PAHs were analyzed using Perkin Elmer GC/MS, which was adjusted with standard reagents for identifying 16 PAH mixtures. Results: The 24 h average PM10 concentration showed considerable inconsistencies, exceeding the WHO standards used for median exposure (25.0 µgm−3). The PAH intensities fluctuated from 7.67 to 34.7 ng/m3 in a suburban area, near a rush-hour traffic road, and from 6.34 to 37.4 ng/m3 close to business and light manufacturing areas. The highest carcinogenic compound levels were found in the Al-Azizia, Al Muzdalifah, and Al Nuzah areas because of the high traffic density, and the lowest concentrations were found in the Al-Haram and Arafat areas throughout the year, as a result of the COVID-19 pandemic health precautions that were undertaken by the government of Saudi Arabia involving border entry limits and limitations of the Umrah and Hajj seasons. Conclusion: This study period is considered extraordinary as the Saudi Arabian government has undertaken successful preventive measures that have had a great effect both on the spread of the pandemic and in reducing air pollution in Makkah. More studies are required to examine PAHs’ carcinogenic effects after the pandemic measures are eased across Makkah.

Distribution and fate of PAHs contaminants deposited in the sediments of North-Western Creeks adjoining the Arabian sea of Mumbai, India: Implications for monitoring

Assessment of 17 polyaromatic hydrocarbons (PAHs) was made to understand the sources, toxicity risk and biological impact in surface sediments of Malad and Versova creek of Mumbai. The concentration of ΣPAHs was found to vary in the range of 2915–4204 ng/g dw (mean 3367 ± 948 ng/gdw). The concentration of high molecular weight PAHs (HMW PAHs) in the range of 2378–3394 ng/g dw (mean 2723 ± 755 ng/g dw) was higher than that of low molecular PAHs (LMW PAHs) which was in the range of 528–810 ng/g dw (mean 644 ± 202 ng/g dw). The contribution of HMW PAHs to the ∑PAHs was 80.86% while that of LMW PAHs was 19.14%. The concentration of carcinogenic PAHs was 1452–1996 ng/g dw (mean 1631 ± 447 ng/g dw) having contribution of 48.43% to the ∑PAHs. The assessment of biological risk and toxicity was made based on toxic equivalent quantity (TEQ) and sediment quality guideline quotient (SQGQ). The PAH levels are feared to increase in coming times thereby creating probable threat to the biological life and health hazard to the nearby human population.

Review of air pollution studies in Sri Lanka

Air pollution is a growing problem in Sri Lanka mainly due to the phenomenal increase in the number of motor vehicles and traffic congestion. Regular air pollution monitoring at automated air quality stations commenced in 1997 with two monitoring stations in Colombo. Results for the period 1997-2003 showed that the levels of sulphur dioxide, nitrogen dioxide, and ozone are steadily increasing while the carbon monoxide levels are decreasing. These pollutants are below their air quality standards except for fine particles (PM10 and PM2.5) which are always above the national standard. Air quality in Kandy is worse than that of Colombo owing to its geographical location, increased vehicle population and traffic congestion. In Kandy, sulphur dioxide, nitrogen dioxide and ozone levels exceeded the standards on 41%, 14% and 28% of the occasions during the period 2001-2005. Presence of carcinogenic polyaromatic hydrocarbons from both kitchen smoke and vehicular exhausts is a definite health hazard. Mean total concentrations of 16 prioritized PAHs (PPAHs) ranged from 57.43 to 1246.12 ng/m3 with a mean of 695.94 ng/m3 in urban heavy traffic locations in Kandy. There are increasing cases of respiratory diseases such as chronic obstructive pulmonary disease due to air pollution in Kandy. Indoor air pollution involving firewood use in congested kitchens is a major health hazard and a few limited studies show that wheezing, bronchitis and asthma incidence is found in children exposed to kitchen smoke. Air quality monitoring using bioindicators is a useful low-cost method to evaluate the pollution levels and the effects of air pollution on plants and vegetation needs more attention.

Интегральная оценка уровня контаминации пищевой продукции приоритетными полиароматическими углеводородами

Polyaromatic hydrocarbons (PAH) occur in the environment as complex mixtures and each congener has different carcinogenic and mutagenic activity. Our research goal was to accomplish an integral assessment of food products contamination with priority PAH basing on their determination with high precision procedures. We validated a procedure for determining the said substances and hygienically assessed contamination of certain food products with benzpyrene, as well as with different carcinogenic and mutagenic PAH equivalents taking into account samples with low contamination. Quantitative determination limit for benz(a)anthracene and benzpyrene was fixed at 0.01 μg/kg; benz(b)fluoranthene and chrysene, 0.1 μg/kg. Detection limit for benz(a)anthracene and benzpyrene amounted to 0.003 μg/kg in our research; for benz(b)fluoranthene and chrysene, 0.03 μg/kg. A procedure for integral assessment of contamination with the examined compounds allowed us to calculate benz(a)anthracene, benzpyrene, benz(b)fluoranthene, and chrysene contents in certain food products taking into account mixture of the examined substances, their individual contributions into aggregated contamination, and their different toxic and mutagenic activity. Median food products contamination with benzpyrene amounted to 0.0065–0.42 μg/kg; PAH taking into account carcinogenic equivalents, 0.03–0.55 μg/kg; PAH based on mutagenic equivalents, 0.04–0.81 μg/kg. Maximum concentrations of benzpyrene and PAH based on carcinogenic and mutagenic equivalents are due to a combination of subsequent technological processes that make for occurrence of the examined substances and also due to physical and chemical properties of the examined food products.

Integral assessment of food products contamination with priority polyaromatic hydrocarbons

Polyaromatic hydrocarbons (PAH) occur in the environment as complex mixtures and each congener has different carcinogenic and mutagenic activity. Our research goal was to accomplish an integral assessment of food products contamination with priority PAH basing on their determination with high precision procedures. We validated a procedure for determining the said substances and hygienically assessed contamination of certain food products with benzpyrene, as well as with different carcinogenic and mutagenic PAH equivalents taking into account samples with low contamination. Quantitative determination limit for benz(a)anthracene and benzpyrene was fixed at 0.01 μg/kg; benz(b)fluoranthene and chrysene, 0.1 μg/kg. Detection limit for benz(a)anthracene and benzpyrene amounted to 0.003 μg/kg in our research; for benz(b)fluoranthene and chrysene, 0.03 μg/kg. A procedure for integral assessment of contamination with the examined compounds allowed us to calculate benz(a)anthracene, benzpyrene, benz(b)fluoranthene, and chrysene contents in certain food products taking into account mixture of the examined substances, their individual contributions into aggregated contamination, and their different toxic and mutagenic activity. Median food products contamination with benzpyrene amounted to 0.0065–0.42 μg/kg; PAH taking into account carcinogenic equivalents, 0.03–0.55 μg/kg; PAH based on mutagenic equivalents, 0.04–0.81 μg/kg. Maximum concentrations of benzpyrene and PAH based on carcinogenic and mutagenic equivalents are due to a combination of subsequent technological processes that make for occurrence of the examined substances and also due to physical and chemical properties of the examined food products.

Aryl Hydrocarbon Receptor Modulates Carcinogenesis and Maintenance of Skin Cancers.

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that responds to a wide range of chemicals, including chemical carcinogens such as dioxins and carcinogenic polyaromatic hydrocarbons, and induces a battery of genes associated with detoxification, proliferation, and immune regulation. Recent reports suggest that AHR plays an important role in carcinogenesis and maintenance of various types of skin cancers. Indeed, AHR is a susceptibility gene for squamous cell carcinoma and a prognostic factor for melanoma and Merkel cell carcinoma. In addition, the carcinogenic effects of ultraviolet (UV) and chemical carcinogens, both of which are major environmental carcinogenetic factors of skin, are at least partly mediated by AHR, which regulates UV-induced inflammation and apoptosis, the DNA repair system, and metabolic activation of chemical carcinogens. Furthermore, AHR modulates the efficacy of key therapeutic agents in melanoma. AHR activation induces the expression of resistance genes against the inhibitors of V600E mutated B-Raf proto-oncogene, serine/threonine kinase (BRAF) in melanoma and upregulation of programmed cell death protein 1 (PD-1) in tumor-infiltrating T cells surrounding melanoma. Taken together, these findings underscore the importance of AHR in the biology of skin cancers. Development of therapeutic agents that modulate AHR activity is a promising strategy to advance chemoprevention and chemotherapy for skin cancers.

Effect of the oxidation process on the molecular interaction of polyaromatic hydrocarbons (PAH) with carbon nanotubes: Adsorption kinetic and isotherm study

Agglomeration is a major setback in the use of pristine multiwall carbon nanotube for many applications. Therefore, application of hydroxyl functionalized multiwall carbon nanotubes (MWCNT-OH) for the removal of naphthalene and fluorine was investigated and compared with pristine MWCNT for the first time. FTIR, BET, TGA, SEM, and TEM were used to investigate the functional group, microstructure and morphology of MWCNT and MWCNT-OH. The BET results showed more mesoporosity for MWCNT-OH than MWCNT. Batch equilibrium adsorption data were fitted to the Langmuir, Freundlich and Temkin models, of which the Langmuir model exhibited the best fit. The correlation of Langmuir model for naphthalene adsorption on MWCNT-OH was observed to be higher (i.e. R2 = 0.9703 for MWCNT-OH and R2 = 0.5082 for MWCNT) while the correlation for adsorption of flourene is higher for MWCNT (i.e. R2 = 0.998 for MWCNT and R2 = 0.9517 for MWCNT-OH). The maximum adsorption capacity (qe) for MWCNT-OH (57.401 ng/g-356.121 ng/g for naph and 61.235 ng/g - 367.361 ng/g for fluorene) was generally higher and more stable for lower concentration ranges while it is comparable with MWCNT (48.177 ng/g - 354.00 ng/g for naph and 59.635 ng/g- 366.709 ng/g for fluorene) at higher concentration. The qe calculated (344.828 ng/g for naph and 357.143 ng/g for fluorene) using PSO was observed to be much closer to experimental qe (356.121 ng/g for naph and 367.361 ng/g for fluorine) for MWCNT-OH adsorbent than MWCNT (cal qe are 384.615 ng/g for naph and 400.000 ng/g for fluorene; exp qe 354.00 ng/g for naph and 366.709 ng/g for fluorene). The value of boundary layer thickness, is >0, this indicates the reaction process is quite complex and is not solely controlled by the intra-particle diffusion. The results of this study indicate the high potential of the developed MWCNT-OH adsorbent as an efficient and successful material for the removal of carcinogenic PAHs from the water body.

Measurement of Benzo(a)pyrene in PM10 Collected in New Delhi

Polyaromatic hydrocarbons (PAH) are the compound which consists of multiple benzene rings bonded in straight, groups or angular forms. They are also found in atmospheric aerosols. In the atmosphere, they can be emitted primarily as a result of incomplete combustion of natural sources (fossil fuels, forest fires, smoke etc.) or anthropogenic sources (coal burning, vehicular emissions, smoke, etc.) or secondarily by atmospheric processes. Depending on the anthropogenic sources, PAHs may occur in significant concentration in urban and industrial ambient air, i.e., bounded with particulate matter (PM). A particle whose aerodynamic diameter is ≤ 10 µm is called PM10. Benzo(a)pyrene (BaP) is among the most toxic and carcinogenic PAHs. Both PM10 and BaP are among the 12 criteria pollutants listed in Indian National Ambient Air Quality Standards (NAAQS). In this paper, BaP concentration in PM10 collected in a representative site of New Delhi was studied during the year 2014–2015. The average concentration of BaP is varied from 0.04 to 25.7 ng m−3. The uncertainty components in measurements were also estimated along with statistical analysis. The most significant uncertainty component is the purity of the BaP standard which has the highest uncertainty contribution as 77%.

Characterization, source identification and risk associated with polyaromatic and chlorinated organic contaminants (PAHs, PCBs, PCBzs and OCPs) in the surface sediments of Hooghly estuary, India

The spatial distribution, source identification and ecotoxicological impact of a group of persistent organic pollutants (POPs: dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexanes (HCHs), polychlorobiphenyls (PCBs), polychlorobenzenes (PCBzs)), and polyaromatic hydrocarbons (PAHs) were investigated in surface sediment samples (0–5 cm, <63 μm grain size) along the ecologically stressed Hooghly River estuary, East India. The results demonstrated a wide range of concentrations (ng/g dry weight) with the following decreasing order: ∑16PAHs (3.3–630) > ∑6DDTs (0.14–18.6) > ∑7PCBs (0.28–7.7) > ∑2PCBzs (0.01–1.3) > ∑5HCH (0.10–0.6), with a dominance of p,p′-DDT and higher molecular weight PAHs. Selected diagnostic ratios indicated a mixture of both pyrolytic and petrogenic sources of PAHs, inputs of weathered DDT and their degradation in oxidizing environment, and a predominance of industrial input over the agricultural wastes. The cumulative impact of the pollutants (effective range medium quotient (ERMq): 0.01–0.16) reflected minimal to low ecotoxicological risk, with highest probability of toxic effects towards surrounding biota at Barrackpore (21%). ∑6DDTs exceeded the effect range low value resulting occasional adverse impact to the sediment dwelling organisms. Among the PAHs, the 4-ringed compounds accounted for 68% of the PAHs. Further, carcinogenic PAHs (BaA, Chry, BbF, BkF, BaP, DahP, Inp) possessed highest cancer risk (CR = 2.09 × 10−3) to the local population when exposed to the sediments from the studied area and ingestion was found to be the primary process of contamination. The study strongly recommends a systematic monitoring of POPs and PAHs, being the Hooghly River water used by local people for their livelihood.

Polycyclic Aromatic Hydrocarbons in Some Processed Smoked Meat, Poultry meat and Fish Products

Sixty samples of smoked meat, smoked turkey, smoked chicken, smoked pasterma, smoked salami and smoked herring (10 for each) were randomly collected from different super markets at Zagazig city, El Sharkia Governorate, Egypt. The incidence of naphthalene in the examined samples was 100%, on contrary the acenaphthylene was under the detection limit (UDL) in all examined samples. The acenaphthene was detected in 20% of examined smoked meat and in 100% of examined smoked herring. Meanwhile fluorine was detected in 60% of smoked herring and it was not detected in other examined smoked products.Phenanthracene was detected in 20%, 40%, 20% and 40% of examined smoked samples of turkey, chicken, pasterma and salami, respectively. The anthracene was detected in 20% of smoked turkey and smoked salami, moreover it was detected in 40% of smoked herring. Pyrene was detected in 20%, 40%, 20%, 80% and 100% of examined smoked samples of turkey, chicken, pasterma, salami and herring, respectively. The Benzo (a) anthracene and chrysene were detected only in examined smoked pasterma samples with percentages of 40% and 20%, respectively. The poly aromatic hydrocarbons (PAHs) benzo(b)fluoranthene,benzo (k)fluoranthene, benzo(a) Pyrene, indeno(1,2,3c-d)Pyrene, dibenzo(a,h) anthracene and benzo (g,h,i) perylene were (UDL). The highest incidence for PAHs fractions was detected in smoked herring. The benzo [a]pyrene is the most hazardous carcinogenic PAHs compound. It was not detected in all examined smoked products. Collectively, no probable risk on Egyptian population from consumption of all examined meat products.

Simultaneous extraction and cleanup of high-lipid organs from white sturgeon (Acipenser transmontanus) for multiple legacy and emerging organic contaminants using QuEChERS sample preparation

The objective of this research was to utilize the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method to extract a broad range of persistent organic pollutants from sturgeon organs (liver and gonad) as indicators of exposure. The analyte list was prioritized to include carcinogenic polyaromatic hydrocarbons (PAHs), the most commonly occurring polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs), persistent bioaccumulative and toxic chemicals (PBTs), and emergent contaminants of concern (ECCs) as indicators of human sewage exposure. White sturgeon (Acipenser transmontanus) were selected for this study to support a larger ecotoxicological study to monitor contaminants as an assessment of fish health. Organ tissues contained high lipid content with percentages of 15% and 34% for liver and gonad, respectively. Overall recoveries from fortified sturgeon tissues were high, 71–98% for PAHs, 60–107% for PBDEs and PCBs, 86–107% for PBT chemicals, and 88–107% for ECCs with the exception of octinoxate (28%) from liver tissues. Analyte recovery trends decreased as analyte lipophilicity and molecular weight increased. These recoveries demonstrate that extraction using QuEChERS can be used for screening of the most common bioaccumulating organic compounds in high lipid fish tissue using a single extraction and analysis.

In Vivo Suppression of Heat Shock Protein (HSP)27 and HSP70 Accelerates DMBA-Induced Skin Carcinogenesis by Inducing Antigenic Unresponsiveness to the Initiating Carcinogenic Chemical.

Heat shock proteins (HSPs) are constitutively expressed in murine skin. HSP27 is present in the epidermis, and HSP70 can be found in both the epidermis and dermis. The purpose of this study was to investigate the role of these proteins in cutaneous chemical carcinogenesis and to determine whether their effects on cell-mediated immune function were a contributing factor. In vivo inhibition of HSP27 and HSP70 produced a reduction in the T cell-mediated immune response to 7,12-dimethylbenz(a)anthracene (DMBA) and benzo(a)pyrene in C3H/HeN mice and resulted in a state of Ag-specific tolerance. When mice were pretreated with anti-HSP27 and anti-HSP70 Abs in vivo prior to subjecting them to a standard two-stage DMBA/12-O-tetradecanoylphorbol-13-acetate cutaneous carcinogenesis protocol, the percentage of mice with tumors was much greater (p < 0.05) in anti-HSP27- and HSP70-pretreated animals compared with mice pretreated with control Ab. Similar results were obtained when the data were evaluated as the cumulative number of tumors per group. Mice pretreated with HSP27 and HSP70 Abs developed more H-ras mutations and fewer DMBA-specific cytotoxic T lymphocytes. These findings indicate that in mice HSP27 and HSP70 play a key role in the induction of cell-mediated immunity to carcinogenic polyaromatic hydrocarbons. Bolstering the immune response to carcinogenic polyaromatic hydrocarbons may be an effective method for prevention of the tumors that they produce.

Re-refining of used lubricating oil

Small amount pure lubricating oil can pollute major amounts of water eg: groundwater as well as the land on which it is spilled. Used engine oil itself contains a number of additives and is contaminated by impurities and residues resulting from the combustion process. Some of them are poisonous and carcinogenic like lead and PAH (poly-aromatic hydrocarbons). Also the oils used in transformers contains PCBs (polychlorinated biphenyls), which are highly carcinogenic as well. From various sources such kind of used lubricating oils are generated and are disposed improperly. The burning of used oil in kilns and incinerators produces lots of ash and carcinogens causing environmental pollution. Waste lubricating oil is a resource that cannot be disposed of randomly due to the presence of pollutants. In response to economic problems and environmental protection, there is a growing trend to regenerate and reuse waste lubricants. By proper recovery and refinement of it, a lot of valuable product can be obtained. The objective of re-refining is to remove the degraded additives and contaminants and to restore the properties of the oil identical to the standards provided by SAE (Society of Automobile Engineers).

The impact of TiO2 nanoparticles on uptake and toxicity of benzo(a)pyrene in the blue mussel (Mytilus edulis)

Nanoparticles are emerging contaminants of concern. Knowledge on their environmental impacts is scarce, especially on their interactive effects with other contaminants. In this study we investigated effects of titanium dioxide nanoparticles (TiO2NP) on the blue mussel (Mytilus edulis) and determined their influence on the bioavailability and toxicity of benzo(a)pyrene (B(a)P), a carcinogenic polyaromatic hydrocarbon (PAH). Blue mussels were exposed to either TiO2NP (0.2 and 2.0mgL−1) or B(a)P (20μgL−1) and to the respective combinations of these two compounds. Aqueous contaminant concentrations, the uptake of Ti and B(a)P into mussel soft tissue, effects on oxidative stress and chromosomal damage were analyzed. The uncoated TiO2NP agglomerated rapidly in the seawater. The presence of TiO2NP significantly reduced the bioavailability of B(a)P, shown by lowered B(a)P concentrations in exposure tanks and in mussel tissue. The activities of antioxidant enzyme superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were impacted by the various exposure regimes, indicating oxidative stress in the contaminant exposure groups. While SOD activity was increased only in the 0.2TiO2NP exposure group, CAT activity was enhanced in both combined exposure groups. The GPx activity was increased only in the groups exposed to the two single compounds. In hemocytes, increased chromosomal damage was detected in mussels exposed to the single compounds, which was further increased after exposure to the combination of compounds. In this study we show that the presence of TiO2NP in the exposure system reduced B(a)P uptake in blue mussels. However, since most biomarker responses did not decrease despite of the lower B(a)P uptake in combined exposures, the results suggest that TiO2NP can act as additional stressor, or potentially alters B(a)P toxicity by activation.

Formation of carcinogenic PAHs (polyaromatic hydrocarbons) in the turbulent diffusive flame

The paper is devoted to the investigation of forming the PAH spectrum in the process of turbulent diffusion combustion of a propane butane mixture. The parameters that influence the oxidation of hydrocarbons and basic PAHs are generalized in terms of the process of mixing, diffusion, chemical kinetics. Areas of intensive formation of the PAH spectrum are revealed.

Indoor air quality in the rural India

PurposeThe purpose of this paper is to assess the exposure of cooks in rural India (55 households) to the indoor air pollution levels emitted from burning of different fuels, i.e. cow dung, wood, liquefied petroleum gas (LPG) and propane natural gas(PNG) kerosene for cooking purposes.Design/methodology/approachIndoor air quality was monitored during cooking hours in 55 rural households to estimate the emissions of PM10, PM2.5, CO, NO2, VOCs and polyaromatic hydrocarbons (PAHs). While, PM10 and PM2.5 were monitored using personal dust samplers on quartz filter paper, CO and VOCs were monitored using on line monitors. The PM10 and PM2.5 mass collected on filter papers was processed to analyse the presence of PAHs using GC.FindingsResults revealed that cow dung is the most polluting fuel with maximum emissions of PM10, PM 2.5, VOCs, CO, NO2 and Benzene followed by wood and kerosene. Interestingly kerosene combustion emits the highest amount of PAHs. Emissions for all the fuels show the presence of carcinogenic PAHs which could be a serious health concern. The composition of LPG/PNG leads to reductions of pollutants because of better combustion process. LPG which is largely propane and butane, and PNG which is 90 per cent methane prove to be healthier fuels. Based on the results, the authors suggest that technological intervention is required to replace the traditional stoves with improved fuel efficient stoves.Practical implicationsThe prevailing weather condition and design of the kitchen in these rural houses severely affect the concentration of pollutants in the kitchen as winter season combined with inadequate ventilation leads to reduced dispersion and accumulation of air pollutants in small kitchens.Originality/valueThe present study provides a detailed analysis of impact of widely‐used cooking practices in India. Even today, countries such as India rely on biomass for cooking practices exposing the cooks to high level of carcinogenic pollutants. Further, women and girls are the most threatened group as they are the primary cooks in these rural Indian settings. Based on the results, the authors suggest that technological as well as policy intervention is required to replace the traditional stoves with improved fuel efficient stoves.

Atherosclerotic Events: The Role of Air Particulate Matter

Epidemiological studies associate the increase of respiratory and cardiovascular mortality and morbidity with high levels of air pollution particulate matter (PM). However, the underlying mechanisms of actions by which PM induce adverse health effects remain to be clearly elucidated. Evidence from experimental studies suggests that particle composition can play an important role in PM-toxicity; however, little is known about the specific participation of components (individually or acting in groups) present in such a complex mixture that accounts for toxicity. Correlations between exposure to PM with an aerodynamic diameter 2.5 or 10 µm (PM2.5 and PM10, respectively) with cardiovascular effects have been demonstrated. Mechanisms of PM at cellular level involve free radical production (by transition metals and organic compounds), oxidative stress, cytokine release, inflammation, endotoxin-mediated damage, stimulation of capsaicin receptors, autonomic nervous system activity, covalent modification of key cellular molecules and increased pro-coagulant activity. The various interaction between particulate matter (e.g carcinogenic polyaromatic hydrocarbon components) and biological molecules trigger cascade events which initiate or aid the progression of disease conditions through cellular responses which could give rise to oxidized and/or mutagenic lesions such as are found within the atherosclerotic plaque and cancers with the most important mechanisms possibly being reactive oxygen species (ROS) generation, oxidative stress and inflammation.

Bio-oils from microwave pyrolysis of agricultural wastes

Pyrolysis of palm kernel shell (PK), wood chips (WC) and sago wastes (SW) was performed on microwave irradiation at different heating time, at moderate temperature 250–390°C. Samples were placed in quartz reactor and subjected to microwave heating in inert atmosphere to afford bio-oils (PKO, WCO and SWO). The highest calorific values recorded are 27.19MJ/kg, 25.99MJ/kg, and 21.99MJ/kg for PKO, WCO and SWO. FTIR spectroscopy showed the presence of functional groups such as phenol, alcohols, ketones, aldehydes and carboxylic acids. The GCMS showed that PKO, WCO and SWO consist of significant quantities of potentially high value hydrocarbons such as monoaromatic hydrocarbons and phenolic compounds. Importantly, the bio-oils do not contain carcinogenic polyaromatic hydrocarbons (PAH). Upon further refining, the bio-oils have a potential as valuable source for fuel or chemical feedstocks.

From Pathology to Chemistry and Back: James W. Cook and Early Chemical Carcinogenesis Research

During the 1920s, concerns over occupational cancers in the tar, coal-gas and synthetic dye industries stimulated investigations into the responsible carcinogenic agents. Chemical pathologist Ernest L. Kennaway and organic chemist James W. Cook at London’s Cancer Hospital Research Institute were the first to identify pure carcinogenic coal-tar polyaromatic hydrocarbons. Cook, who joined Kennaway in 1929, synthesised and tested hundreds of compounds, seeking to identify the exact relationship between chemical constitution and cancer. This paper reviews Cook’s research programme until the early 1940s, and the attempt of his collaborator, Cambridge biochemist Joseph Needham, to identify the biological basis of carcinogenesis. In this, they drew upon structural and functional analogies between recently discovered hormones and carcinogens. Cook established novel ways of studying chemical carcinogenesis, although conflicting empirical results and understandings of cancerous growth militated against the development of a coherent mechanistic theory.