Changes in the microbial community during bioremediation of gasoline-contaminated soil

Abstract We aimed to verify the changes in the microbial community during bioremediation of gasoline-contaminated soil. Microbial inoculants were produced from successive additions of gasoline to municipal solid waste compost (MSWC) previously fertilized with nitrogen-phosphorous. To obtain Inoculant A, fertilized MSWC was amended with gasoline every 3 days during 18 days. Inoculant B received the same application, but at every 6 days. Inoculant C included MSWC fertilized with N–P, but no gasoline. The inoculants were applied to gasoline-contaminated soil at 10, 30, or 50 g/kg. Mineralization of gasoline hydrocarbons in soil was evaluated by respirometric analysis. The viability of the inoculants was evaluated after 103 days of storage under refrigeration or room temperature. The relative proportions of microbial groups in the inoculants and soil were evaluated by FAME. The dose of 50 g/kg of inoculants A and B led to the largest CO2 emission from soil. CO2 emissions in treatments with inoculant C were inversely proportional to the dose of inoculant. Heterotrophic bacterial counts were greater in soil treated with inoculants A and B. The application of inoculants decreased the proportion of actinobacteria and increased of Gram-negative bacteria. Decline in the density of heterotrophic bacteria in inoculants occurred after storage. This reduction was bigger in inoculants stored at room temperature. The application of stored inoculants in gasoline-contaminated soil resulted in a CO2 emission twice bigger than that observed in uninoculated soil. We concluded that MSWC is an effective material for the production of microbial inoculants for the bioremediation of gasoline-contaminated soil.

Genotoxicidad de los hidrocarburos aromáticos policíclicos extraídos mediante el sistema diclorometano-etanol-tolueno en muestras del aire de Cúcuta, Norte de Santander, Colombia / Genotoxicity of polycyclic aromatic hydrocarbons extracted by dichloromethane-ethanol-toluene system air samples from Cúcuta, Norte de Santander, Colombia

Los contaminantes del aire han sido y siguen siendo, los principales factores que contribuyen a las enfermedades crónicas como el asma y enfermedades cardiovasculares. La contaminación del aire por material particulado (PM) es un problema mundial y en los últimos años, el PM se ha convertido en un tema importante de investigación ya que tiene un impacto negativo significativo en la salud humana; el PM es generado por las actividades industriales y tubos de escape de vehículos de motor. Sin embargo, diversos componentes nocivos del PM, como los hidrocarburos aromáticos policiclicos (HAP) en general, son sos­pechosos de ser carcinogénicos. Este trabajo tiene como objetivo identificar los HAP presentes en el PM2.5 del aire de Cúcuta, extraídos por primera vez, mediante el sistema diclorometano-etanol-tolueno e investigar la importancia del fraccionamiento de la materia organica del PM2.5 para detectar los HAP presentes en las fracciones del PM2.5. La identificación de los HAP considerados como contaminantes prioritarios y reconocidos por su afectación a la salud de la población se realizó, mediante cromatografía de gases con detector FID. Los efectos genotoxicos de la materia orgánica del PM2.5 extraída con una mezcla de DCM-etanol-tolueno fueron evaluados mediante el ensayo Cometa.

Air pollutants have been and still are the main factors that contribute to chronic diseases such as asthma and cardio­vascular disease. Air pollution by particulate matter (PM) is a global problem and in recent years, the PM has become an important research topic since it has a significant negative impact on human health; the PM is generated by industrial activities and exhaust pipes of motor vehicles. However, various harmful components of PM such as polycyclic aromatic hydrocarbons (PAHs) in gen­eral, are suspected of being carcinogenic. This work aims to identify the PAHs present in the PM 2.5 air Cúcuta, first extracted by the dichloromethane-ethanol-toluene system and investigate the importance of organic matter fractionation of PM 2.5 to detect PAHs present in the fractions of PM 2.5. The identification of PAHs considered as priority pollutants and recognized for their effects on health of the population was performed by gas chromatography with FID detector. The genotoxic effects of PM2.5 organic mat­ter, extracted with a mixture of DCM-ethanol-toluene, was evaluated by the Comet assay.

Estudio epidemiológico de arsénico en agua subterránea para consumo humano en el territorio del Cluster Lechero Regional, Argentina / Epidemiological study of arsenic in groundwater for human consumption in the territory of the Cluster Lechero Regional, Argentina

En diversas regiones del mundo se han encontrado acuíferos, destinados para el consumo humano, con niveles de arsénico que sobrepasan los límites recomendados por las agencias ambientales o fijados por la legislación, lo que representa un grave problema de salud pública. En el noroeste de la provincia de Santa Fe y sur de Santiago del Estero, área en estudio, los antecedentes indican la existencia de acuíferos con concentraciones de minerales que superan ampliamente los valores recomendados para consumo humano. Estos niveles de salinidad aumentan con la profundidad, y se detecta además, la presencia de tóxicos como el arsénico, siendo un factor condicionante para el aprovechamiento del agua subterránea. En el territorio del Cluster Lechero Regional, se estudió la composición salina del agua subterránea y, en particular, la concentración de arsénico, con el objetivo de establecer niveles de toxicidad y el potencial desarrollo de enfermedades crónicas. Los resultados muestran elevada salinidad y una concentración media de arsénico en la zona de 0,203 mg/L. Estimamos que, para una población de riesgo de 57.436 habitantes que no tienen acceso a sistemas de agua de red, expuestos teóricamente a la concentración de arsénico hallada en este estudio, se manifiesten 500 casos de cáncer atribuibles a este nivel de exposición en los próximos años. La población infantil comprendida entre 0 y 2 años de edad (3.690 niños de la región) podría desarrollar lesiones dérmicas y efectos neurológicos de distinta magnitud.

In various regions of the world, it has been found aquifers, destined for human consumption, with arsenic levels that exceed the limits recommended by the environmental agencies or required by law, so that represents a serious public health problem. In the northwest of the province of Santa Fe and the south of Santiago del Estero, defined study area, the background information indicates the existence of aquifers with concentrations of minerals that far exceeded the recommended values for human consumption. These levels of salinity increases with depth and, in addition, it was detected the presence of toxic substances such as arsenic, being a conditioning factor for the groundwater use. In the territory of the Cluster Lechero Regional, the composition of the saline groundwater was analized and, in particular, the concentration of arsenic was assessed, with the aim of setting levels of toxicity and the potential development of chronic diseases. Results showed high salinity and an average concentration of arsenic in the area of 0.203 mg/L. We believe that for a high risk population of 57,436 inhabitants, with no access to a water system network, and theoretically exposed to the concentration of arsenic found in this study, it would be expected 500 cases of cancer attributable to this level of exposure, in the next years. Children between 0 and 2 years old (3,690 children from the region) could develop skin lesions and neurological effects of different magnitude.

The International Agency for Research on Cancer (IARC) evaluation of the carcinogenicity of outdoor air pollution: focus on China / 癌症

The International Agency for Research on Cancer (IARC) has classified outdoor air pollution and the particulate matter (PM) in outdoor air pollution as carcinogenic to humans, as based on sufficient evidence of carcinogenicity in humans and experimental animals and strong support by mechanistic studies. The data with important contributions to the evaluation are reviewed, highlighting the data with particular relevance to China, and implications of the evaluation with respect to China are discussed. The air pollution levels in Chinese cities are among the highest observed in the world today and frequently exceed health-based national and international guidelines. Data from high-quality epidemiologic studies in Asia, Europe, and North America consistently show positive associations between lung cancer and PM exposure and other indicators of air pollution, which persist after adjustment for important lung cancer risk factors, such as tobacco smoking. Epidemiologic data from China are limited but nevertheless indicate an increased risk of lung cancer associated with several air pollutants. Excess cancer risk is also observed in experimental animals exposed to polluted outdoor air or extracted PM. The exposure of several species to outdoor air pollution is associated with markers of genetic damage that have been linked to increased cancer risk in humans. Numerous studies from China, especially genetic biomarker studies in exposed populations, support that the polluted air in China is genotoxic and carcinogenic to humans. The evaluation by IARC indicates both the need for further research into the cancer risks associated with exposure to air pollution in China and the urgent need to act to reduce exposure to the population.

Air pollution: a smoking gun for cancer / 癌症

Once considered a taboo topic or stigma, cancer is the number one public health enemy in the world. Once a product of an almost untouchable industry, tobacco is indisputably recognized as a major cause of cancer and a target for anticancer efforts. With the emergence of new economic powers in the world, especially in highly populated countries such as China, air pollution has rapidly emerged as a smoking gun for cancer and has become a hot topic for public health debate because of the complex political, economic, scientific, and technologic issues surrounding the air pollution problem. This editorial and the referred articles published in this special issue of the Chinese Journal of Cancer discuss these fundamental questions. Does air pollution cause a wide spectrum of cancers? Should air pollution be considered a necessary evil accompanying economic transformation in developing countries? Is an explosion of cancer incidence coming to China and how soon will it arrive? What must be done to prevent this possible human catastrophe? Finally, the approaches for air pollution control are also discussed.

A bird's eye view of the air pollution-cancer link in China / 癌症

Air pollution in China comes from multiple sources, including coal consumption, construction and industrial dust, and vehicle exhaust. Coal consumption in particular directly determines the emissions of three major air pollutants: dust, sulfur dioxide (SO(2)), and nitrogen oxide (NOx). The rapidly increasing number of civilian vehicles is expected to bring NOx emission to a very high level. Contrary to expectations, however, existing data show that the concentrations of major pollutants [particulate matter-10 (PM10), SO(2), and nitrogen dioxide (NO(2))] in several large Chinese cities have declined during the past decades, though they still exceed the national standards of ambient air quality. Archived data from China does not fully support that the concentrations of pollutants directly depend on local emissions, but this is likely due to inaccurate measurement of pollutants. Analyses on the cancer registry data show that cancer burden related to air pollution is on the rise in China and will likely increase further, but there is a lack of data to accurately predict the cancer burden. Past experience from other countries has sounded alarm of the link between air pollution and cancer. The quantitative association requires dedicated research as well as establishment of needed monitoring infrastructures and cancer registries. The air pollution-cancer link is a serious public health issue that needs urgent investigation.

Impact of fine particles in ambient air on lung cancer / 癌症

Recently, the International Agency for Research on Cancer (IARC) has classified outdoor air pollution and the particulate matter component of outdoor air pollution as class I carcinogen. Air pollution is consistently associated with lung cancer in epidemiologic and experimental studies. The IARC assessment is specifically designed as hazard identification, and it does not quantify the magnitude of the cancer risk. This article addresses the magnitude of the lung cancer risk in the population due to ambient air pollution exposure.

Equivalentes tóxicos de hidrocarburos aromáticos políciclicos en particulado atmosférico en Valencia, Venezuela / Toxic equivalency factors of polycyclic aromatic hydrocarbons (PAHS) in Valencia, Venezuela

El particulado atmosférico de las áreas urbanas contiene mezclas de compuestos contaminantes con diferentes grados de toxicidad como los Hidrocarburos Aromáticos Policíclicos (HAPs), provenientes de las emisiones de combustión incompleta de diversas fuentes no naturales. Los HAPs pueden provocar cáncer, malformaciones congénitas, trastornos del sistema nervioso, entre otros, al ser absorbidos, ya sea por inhalación o ingesta. El factor de equivalencia de toxicidad (FET), es un parámetro estimativo que relaciona la toxicidad de un compuesto con un componente de referencia, cuyo objetivo es evaluar la toxicidad y el riesgo de diversas sustancias y, en el caso de HAPs, el benzo(a)pireno (BaP) es el compuesto de referencia. El objetivo de este trabajo fue estimar el riesgo potencial de exposición a HAPs en habitantes de la zona de estudio a través de los FET. Catorce HAPs fueron extraídos del particulado atmosférico colectado en filtros y analizados por Cromatografía Líquida de Alta Eficiencia con detector de fluorescencia. Se determinó la concentración de los HAPs, se calculó la concentración tóxica equivalente para cada compuesto y de la mezcla total de acuerdo al método propuesto por la Agencia de Protección Ambiental (EPA) de Estados Unidos. La concentración promedio total de HAPs en el particulado fue de 1,97 ng/m³. La contribución del BaP fue del 2,54% en la mezcla total de HAPs. La concentración tóxica equivalente total fue de 0,08 ng/m³ de la mezcla de aire. Las concentraciones tóxicas equivalentes para cada HAP y para el total en el particulado atmosférico no exceden el valor de 1 ng/m³ en equivalentes de BaP, indicado en diversas regulaciones internacionales.

The atmospheric particulate from urban areas contains mixtures of contaminants with different degrees of toxicity such as Polycyclic Aromatic Hydrocarbons (PAHs) derived from emissions from incomplete combustion of various natural sources. PAHs can cause cancer, birth defects and nervous system disorders when they are absorbed either by inhalation or ingestion. The toxic equivalency factor (TEF) is a parameter that relates the toxicity of a compound with a reference component in order to evaluate the toxicity and risk of various substances. The benzo(a)pyrene (BaP) is the reference compound in the case of PAHs mixture. The aim of this study was to estimate the potential risk of exposure to PAHs in people of the study area through the TEF. Fourteen PAHs were extracted from particulate filters and analyzed by liquid chromatography- fluorescence detection. The concentration of PAHs was calculated. The total average concentration of PAHs in the particulate was 1.97 ng/m³. Then, the equivalent toxic concentration of each compound and the total mixture were calculated too according to the method proposed by the United States Environmental Protection Agency (EPA). The contribution of BaP was 2.54% in the total mixture of PAHs. The total equivalent toxic concentration was 0.08 ng/m³ in the air mixture. The toxic equivalent concentrations for each PAH and the total in the atmospheric particulate were not exceeding the value of 1 ng/m3 in BaP equivalent that is the level indicated in international regulations.

Human risk assessment of benzene after a gasoline station fuel leak / Avaliacao de risco humano a benzeno apos vazamento de combustivel em posto de gasolina / Evaluacion de riesgo humano al benceno posterior al derrame de combustible en gasolinera

OBJECTIVE: To assess the health risk of exposure to benzene for a community affected by a fuel leak. METHODS: Data regarding the fuel leak accident with, which occurred in the Brasilia, Federal District, were obtained from the Fuel Distributor reports provided to the environmental authority. Information about the affected population (22 individuals) was obtained from focal groups of eight individuals. Length of exposure and water benzene concentration were estimated through a groundwater flow model associated with a benzene propagation model. The risk assessment was conducted according to the Agency for Toxic Substances and Disease Registry methodology. RESULTS: A high risk perception related to the health consequences of the accident was evident in the affected community (22 individuals), probably due to the lack of assistance and a poor risk communication from government authorities and the polluting agent. The community had been exposed to unsafe levels of benzene (> 5 µg/L) since December 2001, five months before they reported the leak. The mean benzene level in drinking water (72.2 µg/L) was higher than that obtained by the Fuel Distributer using the Risk Based Corrective Action methodology (17.2 µg/L).The estimated benzene intake from the consumption of water and food reached a maximum of 0.0091 µg/kg bw/day (5 x 10-7 cancer risk per 106 individuals). The level of benzene in water vapor while showering reached 7.5 µg/m3 for children (1 per 104 cancer risk). Total cancer risk ranged from 110 to 200 per 106 individuals. CONCLUSIONS: The population affected by the fuel leak was exposed to benzene levels that might have represented a health risk. Local government authorities need to develop better strategies to respond rapidly to these ...

OBJETIVO: Avaliar os riscos à saúde da exposição ao benzeno de comunidade afetada por acidente de vazamento de combustível. MÉTODOS: Dados de acidente de vazamento de combustível ocorrido em Brasília, DF, em 2002, foram obtidos dos relatórios produzidos pelo distribuidor de combustível e submetidos a autoridade ambiental. Informação sobre a população afetada foi obtida em grupos focais com oito participantes. Foram estimados o tempo de exposição e concentração de benzeno na água usando modelo de fluxo subterrâneo acoplado a outro de transporte. A avaliação de risco foi conduzida de acordo com a metodologia da Agência de Registro de Substâncias Tóxicas e Doenças ( Agency for Toxic Substances and Disease Registry ). RESULTADOS: Alta percepção de risco à saúde relacionada ao acidente foi observada na população afetada (22 indivíduos), provavelmente devido à falta de assistência e à comunicação de risco deficiente do governo e agente poluidor. A comunidade esteve exposta a níveis inseguros de benzeno na água (> 5 µg/L) a partir de dezembro de 2001, cinco meses antes de ser reportado o vazamento. A concentração média de benzeno na água consumida (72,2 µg/L) foi maior que aquela estimada pelo distribuidor usando a metodologia Ação Corretiva Baseada em Risco ( Risk Based Corrective Action ) (17,2 µg/L). A ingestão estimada de benzeno pelo consumo de água e frutas alcançou 0,0091 µg/kg pc/dia (risco de 5 x 10-7 câncer per 106 indivíduos). O nível de benzeno no vapor d´água durante o banho atingiu 7,5 µg/m3 para ...

OBJETIVO: Evaluar los riesgos para la salud de la exposición al benceno en comunidad afectada por accidente de derrame de combustible. MÉTODOS: Datos del accidente ocurrido en el Distrito Federal (Brasil), fueron obtenidos de los informes realizados por el distribuidor de combustible y sometidos a la autoridad ambienta. Información sobre la población afectada fue obtenida en grupos focales con 8 participantes. Se hicieron estimaciones del tiempo de exposición y concentración de benceno en el agua usando modelo de flujo subterráneo acoplado a otro de transporte. La evaluación de riesgo fue conducida de acuerdo con la metodología de la "Agency for Toxic Substances and Disease Registry". RESULTADOS: Alta percepción de riesgo para la salud relacionada con el accidente fue observada en la población afectada (22 individuos), probablemente debido a la falta de asistencia y a la comunicación de riesgo deficiente del gobierno y agente contaminante. La comunidad estuvo expuesta a niveles inseguros de benceno en el agua (>5 µg/L) a partir de diciembre de 2001, cinco meses antes de ser reportado el derrame. La concentración promedio de benceno en el agua consumida (72,2 µg/L) fue mayor que la estimada por el distribuidor usando la metodología "Risk Based Corrective Action" (17,2 µg/L). La ingestión estimada de benceno por el consumo de agua y frutas alcanzó 0,0091 µg/kg pc/día (riesgo de 5 x 10-7 de cáncer per 106 individuos). El nivel de benceno en el vapor de agua durante el baño alcanzó 7,5 µg/m3 en niños (riesgo de cáncer de hasta 1 per 104). El Riesgo carcinogénico total fue de 110 a 200 per 106 individuos. CONCLUSIONES: La población afectada por el derrame de combustible estuvo expuesta ...

Head and Neck Squamous Cell Carcinoma: Genetic Polymorphisms and Occurrence Risks / 한양의대학술지

Head and neck squamous cell carcinoma (HNSCC), which is the 5th most common cancer worldwide, is believed to be induced by environmental carcinogens and host genetic factors. The main etiologic environmental factors are tobacco, alcohol, viral infection, nutritional deficit, mineral inhalation and history of radiation exposure. Accumulating evidence has shown that genetic polymorphisms influence the risk of environmental carcinogenesis, and that genetic susceptibility plays an important role in the development of HNSCC. Genetic susceptibility to HNSCC may be due to genetic polymorphisms in genes controlling both carcinogen metabolism and repair of DNA damage. We analyzed the associations between genetic polymorphisms in the xenobiotics metabolizing gene, alcohol metabolizing gene and DNA repair genes and the risk of HNSCC in an at-risk Korean population. In conclusion, ADH1B +3170A>G His48Arg and XRCC1 R194W (C>T) polymorphism are associated with an increased risk of HNSCC, and these genotypes could be useful biomarkers for identifying Koreans with a greater risk of HNSCC.

Hexavalent chromium reduction by aerobic heterotrophic bacteria indigenous to chromite mine overburden

Microbiological analysis of overburden samples collected from chromite mining areas of Orissa, India revealed that they are rich in microbial density as well as diversity and dominated by Gramnegative (58%) bacteria. The phenotypically distinguishable bacterial isolates (130) showed wide degree of tolerance to chromium (2-8 mM) when tested in peptone yeast extract glucose agar medium. Isolates (92) tolerating 2 mM chromium exhibited different degrees of Cr+6 reducing activity in chemically defined Vogel Bonner (VB) broth and complex KSC medium. Three potent isolates, two belonging to Arthrobacter spp. and one to Pseudomonas sp. were able to reduce more than 50 and 80% of 2 mM chromium in defined and complex media respectively. Along with Cr+6 (MIC 8.6-17.8 mM), the isolates showed tolerance to Ni+2, Fe+3, Cu+2 and Co+2 but were extremely sensitive to Hg+2 followed by Cd+2, Mn+2 and Zn+2. In addition, they were resistant to antibiotics like penicillin, methicillin, ampicillin, neomycin and polymyxin B. During growth under shake-flask conditions, Arthrobacter SUK 1201 and SUK 1205 showed 100% reduction of 2 mM Cr+6 in KSC medium with simultaneous formation of insoluble precipitates of chromium salts. Both the isolates were also equally capable of completely reducing the Cr+6 present in mine seepage when grown in mine seepage supplemented with VB concentrate

Linfoma no Hodgkin gástrico asociado a intoxicación por metales pesados / Gastric non-Hodgkin lymphoma associated with heavy metal exposures

El Linfoma no Hodgkin (LNH) extraganglionar es una neoplasia maligna que corresponde al 40% de los casos de LNH, siendo el tracto gastrointestintal (TGI) la localización más común. Dentro del TGI es el estómago el órgano más afectado (60%). Presentamos el caso de un hombre de 52 años trabajador en empresa minera por más de 10 años, el cual es derivado al Servicio de Gastroenterología por presentar un cuadro de epigastralgia, náuseas y baja de peso. La endoscopía digestiva mostró una lesión ulcerada en cuerpo gástrico a la cual se le tomaron múltiples biopsias. El estudio histológico y el posterior análisis inmunohistoquímico permitieron realizar el diagnóstico de LNH B difuso de células grandes. Asimismo, el paciente presentó compromiso de múltiples órganos en relación a exposición crónica de metales pesados, lo cual fue comprobado en el mineralograma, siendo las de mayor concentración el uranio, talio, arsénico, plomo y mercurio. En la literatura se ha descrito la asociación de exposición laboral crónica a Uranio y Arsénico con la presentación de LNH de compromiso gastrointestinal. Por tal motivo, el compromiso gástrico no se puede considerar como un daño aislado, sino más bien parte del compromiso sistémico asociado a concentraciones elevadas de metales. La minería constituye el principal motor de ingresos económicos para el Perú, sin embargo, no existen reportes hasta la fecha de la asociación de LNH de compromiso gastrointestinal en relación a exposición laboral a metales pesados.

Primary extranodal Non-Hodgkin lymphoma (NHL) is a non epithelial tumours that accounts for 40% of cases of NHL. Spread of nodal lymphomas to the gastrointestinal tract (GIT) is the most common location. Within the GIT is the stomach the most affected organ (60%). We report the case of 52-year- old man, mining company worker for over 10 years, which is derived to the Service of Gastroenterology with history of epigastric pain, nausea, vomiting and weight loss. Upper gastrointestinal endoscopic examination revealed an ulcerated lesion on greater curve of stomach and histopathological examination and subsequent immunohistochemical analysis showed diffuse large B cell gastric NHL. Also, the patient had multiple organ involvement in relation to chronic exposure to heavy metals, which was found in the mineralograma, with the highest concentration of uranium, thallium, arsenic, lead and mercury. The literature has described the association of chronic occupational exposure to uranium and arsenic with NHL presenting gastrointestinal involvement. Therefore, gastric commitment can not be considered as an isolated injury, but rather part of systemic involvement associated with elevated concentrations of metals. Mining is a key driver of income for Peru; however, there are no reports to date of the association of gastrointestinal NHL commitment regarding occupational exposure to heavy metals.

Chi-square analysis of the reduction of ATP levels in L-02 hepatocytes by hexavalent chromium

This study explored the reduction of adenosine triphosphate (ATP) levels in L-02 hepatocytes by hexavalent chromium (Cr(VI)) using chi-square analysis. Cells were treated with 2, 4, 8, 16, or 32 μM Cr(VI) for 12, 24, or 36 h. Methyl thiazolyl tetrazolium (MTT) experiments and measurements of intracellular ATP levels were performed by spectrophotometry or bioluminescence assays following Cr(VI) treatment. The chi-square test was used to determine the difference between cell survival rate and ATP levels. For the chi-square analysis, the results of the MTT or ATP experiments were transformed into a relative ratio with respect to the control (%). The relative ATP levels increased at 12 h, decreased at 24 h, and increased slightly again at 36 h following 4, 8, 16, 32 μM Cr(VI) treatment, corresponding to a "V-shaped" curve. Furthermore, the results of the chi-square analysis demonstrated a significant difference of the ATP level in the 32-μM Cr(VI) group (P < 0.05). The results suggest that the chi-square test can be applied to analyze the interference effects of Cr(VI) on ATP levels in L-02 hepatocytes. The decreased ATP levels at 24 h indicated disruption of mitochondrial energy metabolism and the slight increase of ATP levels at 36 h indicated partial recovery of mitochondrial function or activated glycolysis in L-02 hepatocytes.

[Evaluation of exposure to carcinogenic agents in Tehran citizens]

Cancer is a major health problem worldwide. Several factors are involved in cancer. However the role of environmental factors is more prominent. Modification of these factors into proper behavior would help to prevent cancer. Accordingly this study was done with the aim of evaluating the exposure to carcinogenic agents in Tehran citizens. It was a descriptive, cross- sectional survey. The sample consisted of 2500 Tehran citizens who were recruited by systematic cluster random sampling. Data was collected by a researcher- made instrument with five parts including demographic information, and questions regarding alcohol and tobacco use, radiation exposure, exposure to chemical agents, and reaction to stress. Data was analyzed by descriptive statistics using SPSS-PC [v. 11.5]. The result showed that10% of the sample had consumed alcohol, 16% were Smokers. 22% were encountered U.V, 88/4% had not contact with chemical agents at work place. 94/4% were not taking oral contraceptives. The majority of Tehran citizens [45/8%] got angry sometimes. Most of Tehran Citizens exposed to carcinogenic agents, especially radiation, cigarette smoke, chemicals and with less intensity with stressors. Due to alcohol being forbidden in Islam, no clear information is available about its consumption. To educate people about the carcinogenic agents can be helpful

Indoor radon survey in Shiraz-Iran using developed passive measurement method

While in the open air the amount of radon gas is very small and does not pose a health risk, in confined spaces, radon can accumulate to relatively high levels and become a health hazard. Exposure to high levels of radon has been associated with an increased risk of lung cancer, depending on the time length of exposure. Radon level in dwelling of Shiraz with 1,200,000 populations has been sampled and analyzed in this study. Our study could be considered the largest radon study in Iran both time and area wise. In this study, radon [222Rn] concentration in residential dwellings in Shiraz-Iran was sampled and measured during two consecutive six month periods in 2009-2010. We used Solid State Nuclear Track Detectors [SSNTD], CR-39 polycarbonate films. The survey parameters of radon concentrations were floor types, construction materials and dwelling's age. Annual average indoor radon concentration for the survey period was 94 +/- 52 Bq/m3. The calculated mean annual effective doses in basements and different floors were less than the lowest limit recommended action level of 3 mSv by ICRP. High radon concentrations are measured in basements and old dwellings; however, due to rapidly changing housing structures and ventilation practices with no intervention, lower levels of radon concentration has been expected in Shiraz

Radium and Radon exhalation studies of soil

Everyone is exposed to radon because it is present everywhere with varying concentrations. Radon and its progeny are well established as lung carcinogenic. Track etch technique using LR-115 plastic track detectors has been used to measure the effective radium content and radon exhalation rates in soil samples collected from urban area of Etah district of Uttar Pradesh province in Northern India. The values of effective radium content are found to vary from 27.87 to 45.14 Bq.kg-[1] with a mean value of 34.98 Bq.kg-[1]. The mass exhalation rates of radon vary from 2.38 _ 10[-6] to 3.86 _ 10[-6] Bq.kg[-1].d[-1] with a mean value of 2.99 _ 10-6 Bq.kg[-1].d[-1]. The surface exhalation rates of radon have been found to vary from 6.19 _ 10[-5] to 10.03 _ 10[-5] Bq.m [-2].d[-1] with a mean value of 7.77 _ 10[-5] Bq.m [-2].d[-1]. Radon exhalation study is important for understanding the relative contribution of the material to the total radon concentration found inside the dwellings. The values of radium and radon exhalation rates are found to be below the safe limit recommended by OECD, 1979

effects of internal wall covering materials on hazards of indoor radon concentrations in houses of Iran

Radon gas emanating from underground can concentrate indoor and reach levels, which represent a risk to people's health. According to WHO [World Health Organization] and ERA [Environmental Protection Agency], radon is the second leading cause of lung cancer in the world. Due to the direct correlation of lung cancer and radon exposure, it is ideal to evaluate the hazards of radon accumulation in the Iran dwellings with different materials by direct measurement of the radon concentrations using accurate, simple and fast method. The aim of this study was to measure variation of radon concentrations with different covering materials on internal building surfaces including walls, which are used in Iran dwellings. A special chamber with changeable walls of different covering materials [gypsum, wallpaper, oil dye, plastic dye, wood board, and Belka] was made. Radioactive lantern mantles were used for elevating the radon [220]Rn] levels in the chamber artificially. Ventilation in the chamber had been such way that accumulation of radon could be possible. Active measurement by Prassi portable radon gas surveyor was performed for staging purposes. The average radon concentration for wood and plastic dye was 869.0 +/- 66.7 and 936.8_60.6 [bq/m[3]], respectively, while that for wallpaper and gypsum was 449.2 +/- 101.7, 590.9 +/- 49.0 [bq/m[3]], significantly lower than other covers. The average radon concentration for oil dye and Belka cover was 668.3 +/- 42.3, 697.2 +/- 136.7 [bq/m[3]], respectively. Individuals living in a house with internal wall covering materials of gypsum and wallpaper receive an average annual dose smaller than one living in a house with internal wall covering materials of wood board and plastic dye. Using wallpaper and gypsum as an internal cover for the dwellings suggested