Unboxing the molecular modalities of mutagens in cancer

Environmental Science and Pollution Research - The etiology of the majority of human cancers is associated with a myriad of environmental causes, including physical, chemical, and biological...     

The association between air pollution and cancers: controversial evidence of a systematic review

Environmental Science and Pollution Research - There are inconsistent reports on the association between air pollution and cancers. This systematic review was, therefore, conducted to ascertain the...     

Focus on Multi-targeted Role of Curcumin: a Boon in Therapeutic Paradigm

Environmental Science and Pollution Research - Curcumin is a polyphenolic compound that exhibited good anticancer potential against different types of cancers through its multi-targeted effect like...     

Probabilistic approach for health hazard assessment of trihalomethanes through successive showering events

Environmental Science and Pollution Research - Trihalomethanes (THMs) are common disinfection by-products in chlorinated tap waters. They can cause various cancers and non-cancer health hazards....     

Antitumor effect of copper nanoparticles on human breast and colon malignancies

Environmental Science and Pollution Research - Breast and colon carcinomas are two types of common cancers which lead to cancer-related deaths. Due to their cytotoxic potential against cancer...     

Distance-weighted traffic density in proximity to a home is a risk factor for leukemia and other childhood cancers

Occupational exposure to elevated concentrations of benzene is a known cause of leukemia in adults. Concentrations of benzene from motor vehicle exhaust could be elevated along highly trafficked streets. Several studies have reported significant associations between proximity to highly trafficked streets and the occurrence of childhood cancers and childhood leukemia. These associations may be due to chronic exposure to benzene or other carcinogenic components of vehicle exhaust from these nearby streets or to some other factor (e.g., noise, increased light exposure, or some unaccounted--for socioeconomic variable). We used data for homes studied in an earlier childhood cancer study conducted in Denver, CO, in the 1980s. No air pollution measurements were made in the original study. We identified the highest trafficked street near each study home and obtained the traffic density in 1979 and 1990. Traffic density was weighted for the distance from the street to the home using 3 different widths of Gaussian curves to approximate the decay of the emissions into the surrounding neighborhoods. The associations between the 750-ft-wide distance-weighted traffic density metrics and all childhood cancers and childhood leukemia are strongest in the highest traffic density category (> or = 20,000 vehicles per day [VPD]). The odds ratio is 5.90 (95% confidence interval [CI] 1.69-20.56) for all cancers and 8.28 (95% CI 2.09-32.80) for leukemia. The results are suggestive of an association between proximal high traffic streets with traffic counts > or = 20,000 VPD and childhood cancer, including leukemia.     

Promotive effect of diethylstilbestrol on urethan-induced mouse lung tumorigenesis

The effect of diethylstilbestrol (DES) on urethan-induced mouse lung tumorigenesis was assessed by a single intraperitoneal injecting of urethan (50 mg/kg) or/and multi intramuscular injecting of DES (5 or 50 mg/kg). All mice were sacrificed 18 weeks after administration, and the lung tumors were examined histopathologically. DES did not produce an elevated lung tumor response when administered alone, but it produced a statistically significant enhancement of incidence of tumors, average number of tumors, incidence of cancers and constituent ratio of malignant tumors when given in conjunction with urethan. The results indicated that DES may be a promoter in lung tumor formation.     

Mortality of US pentachlorophenol production workers through 2005

A cohort of 2122 US pentachlorophenol (PCP) production workers from four plants in the National Institute for Occupational Safety and Health Dioxin Registry was exposed to PCP and to polychlorinated dibenzo-p-dioxin and dibenzofuran contaminants of PCP production. A subcohort of 720 was also exposed to 2,3,7,8-tetrachlorodibenzodioxin, a contaminant of trichlorophenol (TCP) while using TCP or a TCP derivative. PCP and several production contaminants have been implicated as animal carcinogens. A priori hypotheses were that the cohort would have elevated standardized mortality ratios (SMRs) for aplastic anemia, soft-tissue sarcoma, and non-Hodgkin lymphoma, as suggested by human studies, and for leukemia and liver, adrenal, thyroid, and parathyroid cancer, as suggested by animal studies. From 1940 to 2005 1165 deaths occurred with an overall SMR of 1.01 [95% confidence limits (CI), 0.95-1.07]. Overall cancer mortality (326 deaths, SMR 1.17, CI 1.05-1.31) was in statistically significant excess. There were excess deaths for trachea, bronchus and lung cancers (126 deaths, SMR 1.36, CI 1.13-1.62), non-Hodgkin lymphoma (17 deaths, SMR 1.77, CI 1.03-2.84), chronic obstructive pulmonary disease (63 deaths, SMR 1.38, CI 1.06-1.77), and medical complications (5 deaths, SMR 3.52, CI 1.14-8.22). In race- and sex-specific analyses, white males had increased non-Hodgkin lymphoma mortality (17 deaths, SMR 1.98, CI 1.15-3.17) and males of other races had increased leukemia mortality (four deaths, SMR 4.57, CI 1.25-11.7). The excess of cancers of a priori interest, non-Hodgkin lymphoma and leukemia, provide some support for the carcinogenicity of PCP, however, further studies with more detailed exposure assessment are needed.     

Lung cancer mortality and exposure to atmospheric aerosol particles in Guangzhou,China

In recent years, China and other emerging countries have been experiencing severe air pollution problems with high concentrations of atmospheric aerosol particles. Satellite measurements indicate that the aerosol loading of the atmosphere in highly populated regions of China is about 10 times higher than, for example, in Europe and in the Eastern United States. The exposure to extremely high aerosol concentrations might lead to important human health effects, including respiratory and cardiovascular diseases as well as lung cancers. Here, we analyze 52-year historical surface measurements of haze data in the Chinese city of Guangzhou, and show that the dramatic increase in the occurrence of air pollution events between 1954 and 2006 has been followed by a large enhancement in the incidence of lung cancer.     

A global health problem caused by arsenic from natural sources

Arsenic is a carcinogen to both humans and animals. Arsenicals have been associated with cancers of the skin, lung, and bladder. Clinical manifestations of chronic arsenic poisoning include non-cancer end point of hyper- and hypo-pigmentation, keratosis, hypertension, cardiovascular diseases and diabetes. Epidemiological evidence indicates that arsenic concentration exceeding 50 microg l(-1) in the drinking water is not public health protective. The current WHO recommended guideline value for arsenic in drinking water is 10 microg l(-1), whereas many developing countries are still having a value of 50 microg l(-1). It has been estimated that tens of millions of people are at risk exposing to excessive levels of arsenic from both contaminated water and arsenic-bearing coal from natural sources. The global health implication and possible intervention strategies were also discussed in this review article.     

PCB exposure and potential future cancer incidence in Slovak children: an assessment from molecular finger printing by Ingenuity Pathway Analysis (IPA®) derived from experimental and epidemiological investigations

The risk of cancer due to PCB exposure in humans is highly debated. In eastern Slovakia, high exposure of the population to organochlorines (especially PCBs) was associated with various disease and disorder pathways, viz., endocrine disruption, metabolic disorder & diabetes, and cancer, thereby disturbing several cellular processes, including protein synthesis, stress response, and apoptosis. We have evaluated a Slovak cohort (45-month children, at lower and higher levels of PCB exposure from the environment) for disease and disorder development to develop early disease cancer biomarkers that could shed new light on possible mechanisms for the genesis of cancers under such chemical exposures, and identify potential avenues for prevention.

Microarray studies of global gene expression were conducted from the 45-month-old children on the Affymetrix platform followed by Ingenuity Pathway Analysis (IPA®) to associate the affected genes with their mechanistic pathways. High-throughput qRT-PCR TaqMan low-density array (TLDA) was performed to further validate the selected genes on the whole blood cells of the most highly exposed children from the study cohort (n = 71).

TP53, MYC, BCL2, and LRP12 differential gene expressions suggested strong relationships between potential future tumor promotion and PCB exposure in Slovak children. The IPA analysis further detected the most important signaling pathways, including molecular mechanism of cancers, prostate cancer signaling, ovarian cancer signaling, P53 signaling, oncostatin M signaling, and their respective functions (viz., prostate cancer, breast cancer, progression of tumor, growth of tumor, and non-Hodgkin’s disease). The results suggest that PCB exposures, even at the early age of these children, may have lifelong consequences for the future development of chronic diseases.

     

Health risks from arsenic-contaminated soil in Flin Flon–Creighton,Canada: Integrating geostatistical simulation and dose–response model

Elevated concentrations of arsenic were detected in surface soils adjacent to a smelting complex in northern Canada. We evaluated the cancer risks caused by exposure to arsenic in two communities through combining geostatistical simulation with demographic data and dose–response models in a framework. Distribution of arsenic was first estimated using geostatistical circulant-embedding simulation method. We then evaluated the exposures from inadvertent ingestion, inhalation and dermal contact. Risks of skin caner and three internal cancers were estimated at both grid scale and census-unit scale using parametric dose–response models. Results indicated that local residents could face non-negligible cancer risks (skin cancer and liver cancer mainly). Uncertainties of risk estimates were discussed from the aspects of arsenic concentrations, exposed population and dose–response model. Reducing uncertainties would require additional soil sampling, epidemic records as well as complementary studies on land use, demographic variation, outdoor activities and bioavailability of arsenic.     

EPA’s Perspective on Risks from Residential Radon Exposure

Indoor radon has been judged to be the most serious environmental carcinogen which the EPA must address for the general public. The optimal strategy for dealing with this problem depends on the magnitude of the risk, how the risk is distributed within the population, as well as the effectiveness and costs of mitigation measures. Based on current exposure and risk estimates, radon exposure in single-family houses may be a causal factor in roughly 20,000 lung cancer fatalities per year. Most of these projected fatalities are attributable to exposures in houses with average or moderately elevated radon levels (below 10 pCi/L). Hence to appreciably reduce radon-induced lung cancers, remediation efforts must include houses not highly elevated in radon. From either an individual risk or a cost-benefit standpoint, reduction of a few pCi/L per home appears to be justified. The optimal strategy for dealing with the indoor radon problem depends on the magnitude of the risk per unit exposure, the distribution of exposures in houses, and the effectiveness and costs of mitigation. EPA’s current views with respect to these factors and the associated uncertainties are discussed.     

Indoor and outdoor carbonyl compounds in the hotel ballrooms in Guangzhou,China

Twenty-one carbonyl compounds were measured simultaneously at four hotel ballrooms in urban Guangzhou during the autumn, 2002. In each ballroom, measurements were carried out in business hours in the evening (20:30–24:00) on 7 consecutive days without any disturbance of the ballroom's normal operation. Nineteen out of the 21 target carbonyl compounds were identified in indoor and outdoor air. In the outdoor environment, formaldehyde was the most abundant carbonyl, followed by acetaldehyde, and there existed a strong correlation between formaldehyde and acetaldehyde. In the indoor air, however, acetaldehyde was the most abundant carbonyl, its concentrations seemed to be affected significantly by smoking. The indoor concentrations of carbonyls were found higher than their outdoor counterparts with only a few exceptions. Further studies concerning the indoor/outdoor ratios and mutual correlation of the carbonyls indicated that apart from direct emission from indoor materials and infiltration of outdoor air, other anthropogenic sources, e.g. tobacco smoke, also significantly contributed to carbonyl compounds. The possible sources of some high molecular weight carbonyls, e.g. nonanaldehyde, were also discussed briefly. Preliminary estimate of the exposures and risks due to carbonyls in the ballrooms was made, which indicated that long-term exposure in such places might cause increased chance of developing cancers.     

Double trouble: health risks of accidental sewage release

Occupational health risks from long-term exposure to sewage are well documented [Am J. Ind. Med. 25 (1994) 59; Ann. Agric. Environ. Med. 81 (2001) 39; Am J. Ind. Med. 40 (2001) 170]. Some studies suggest an increase in the incidence of specific cancers [Am J. Ind. Med. 19 (1991) 75; J. Occup. Med. 36 (1994) 31]. There are also many reports of acute fatalities in confined spaces (sewage chambers and pipes) [H&S at Work 13 (1991), 10; FACE report: sewer worker dies when inflatable sewer plug bursts in Washington, DC, Performer, National Institute For Occupational Safety and Health, 19th July 1990]. In a residential area incidents of sudden sewage release can be regarded as double trouble because both the emergency service personnel and the local residents may be exposed to a galaxy of chemical and microbiological agents present in sewage. However, data on the effects of acute non-occupational exposure due to accidental sewage releases is still very limited. The incidents investigated here took place at two different locations in the southern part of the UK. In both incidents the symptoms experienced by those exposed were more serious than expected by the public health experts.     

An Epidemiological Study of Exposure to Coal Tar Pitch Volatiles Among Coke Oven Workers

Recent studies of mortality among coke plant workers indicate that there is an excess of respiratory cancer among men employed at the coke ovens and that the mortality is related to work areas and length of exposure to coal tar effluents, the body of information presented in this paper is directed to categorization of coke oven jobs into different work areas in terms of exposure to coal tar pitch volatiles developing an index of cumulative exposure to investigate the dose-response relationship between exposure and mortality. The exposure data have been taken from a study conducted by the Pennsylvania Department of Health, State Division of Occupational Health, and mortality data are based on a long-term study of steelworkers, conducted by the Department of Biostatistics, University of Pittsburgh. A summary index calculated for each worker combining the level of exposure and length of time exposed indicates that, as expected, both these factors are related to the development of cancer, particularly cancers of the respiratory system.

Conclusions of note are: Measured levels of coal tar pitch volatiles are 2-3 times higher for men who work at the top of coke ovens as compared to men employed at the side of the ovens. Even though the specific carcinogenic element or elements in the coke oven environment are not known at the present time, in-. creasing levels of exposure to coal tar pitch volatiles are related to art increased risk of dying from malignant neoplasms. Further coal tar pitch volatile measurements need to be made and analyses designed which will specify the dose-response relationship more precisely. This will provide information necessary to evaluate the recommended Threshold Limit Value.     

Nitrate contamination in water resources,human health risks and its remediation through adsorption: a focused review

The level of nitrate in water has been increasing considerably all around the world due to vast application of inorganic nitrogen fertiliser and animal manure. Because of nitrate’s high solubility in water, human beings are getting exposed to it mainly through various routes including water, food etc. Various regulations have been set for nitrate (45–50 mgNO₃^?/L) in drinking water to protect health of the infants from the methemoglobinemia, birth defects, thyroid disease, risk of specific cancers, i.e. colorectal, breast and bladder cancer caused due to nitrate poisoning. Different methods like ion exchange, adsorption, biological denitrification etc. have the ability to eliminate the nitrate from the aqueous medium. However, adsorption process got preference over the other approaches because of its simple design and satisfactory results especially with surface modified adsorbents or with mineral-based adsorbents. Different types of adsorbents have been used for this purpose; however, adsorbents derived from the biomass wastes have great adsorption capacities for nitrate such as tea waste-based adsorbents (136.43 mg/g), carbon nanotube (142.86 mg/g), chitosan beads (104 mg/g) and cetyltrimethylammonium bromide modified rice husk (278 mg/g). Therefore, a thorough literature survey has been carried out to formulate this review paper to understand various sources of nitrate pollution, route of exposure to the human beings, ill effects along with discussing the key developments as well as the new advancements reported in procuring low-cost efficient adsorbents for water purification.

     

Health care industries: potential generators of genotoxic waste

Health care waste includes all the waste generated by health care establishments, research facilities, and laboratories. This constitutes a variety of chemical substances, such as pharmaceuticals, radionuclides, solvents, and disinfectants. Recently, scientists and environmentalists have discovered that wastewater produced by hospitals possesses toxic properties due to various toxic chemicals and pharmaceuticals capable of causing environmental impacts and even lethal effects to organisms in aquatic ecosystems. Many of these compounds resist normal wastewater treatment and end up in surface waters. Besides aquatic organisms, humans can be exposed through drinking water produced from contaminated surface water. Indeed, some of the substances found in wastewaters are genotoxic and are suspected to be potential contributors to certain cancers. The aim of this study was to evaluate the genotoxic and cytotoxic potential of wastewaters from two hospitals and three clinical diagnostic centers located in Jaipur (Rajasthan State), India using the prokaryotic Salmonella mutagenicity assay (Ames assay) and the eukaryotic Saccharomyces cerevisiae respiration inhibition assay. In the Ames assay, untreated wastewaters from both of the health care sectors resulted in significantly increased numbers of revertant colonies up to 1,000–4,050 as measured by the Salmonella typhimurium TA98 and TA100 strains (with and without metabolic activation) after exposure to undiluted samples, which indicated the highly genotoxic nature of these wastewaters. Furthermore, both hospital and diagnostic samples were found to be highly cytotoxic. Effective concentrations at which 20 % (EC₂₀) and 50 % (EC₅₀) inhibition of the respiration rate of the cells occurred ranged between ～0.00 and 0.52 % and between 0.005 and 41.30 % (calculated with the help of the MS excel software XLSTAT 2012.1.01; Addinsoft), respectively, as determined by the S. cerevisiae assay. The results indicated that hospital wastewaters contain genotoxic and cytotoxic components. In addition, diagnostic centers also represent small but significant sources of genotoxic and cytotoxic wastes.     

Environmental exposure to PCBs and cancer incidence in eastern Slovakia

In a population-based cross-sectional study, we compared serum levels of 15 polychlorinated biphenyl (PCB) congeners and three organochlorine pesticides in residents of two districts in eastern Slovakia, one with extensive environmental contamination from a former PCB production site (Michalovce) and the other matched on geography but with low (background) levels (Svidnik). The age-adjusted geometric means for sum of 15 measured PCB congeners were statistically significantly higher in subjects from the Michalovce district for both sexes: 3327.6 versus 1331.4 ng/g of lipid in males, 2751.8 versus 992.2 ng/g of lipid in females. Levels of DDE and DDT were also significantly higher, although the absolute differences were less pronounced. There was no substantial difference in HCB levels between the districts. We also conducted an ecologic study to compare cancer incidence occurring in these same two districts from 1985 through 1994. We calculated standardized incidence ratios (SIRs) and 95% confidence intervals for each district using indirect standardization and rates from eastern Slovakia. Among males from Michalovce (exposed), but not Svidnik (unexposed), there was an excess of cancer of the tongue (SIR=1.46; 1.06-1.96), stomach (SIR=1.15; 1.00-1.32), lung (SIR=1.14; 1.04-1.24), testis (SIR=1.40; 0.97-1.97), and kidney (SIR=1.23; 0.98-1.52), and lower than expected incidence of prostate cancer (SIR=0.83; 0.69-0.97); in contrast, there was an excess of peritoneal (SIR=3.05; 1.11-6.63) and laryngeal cancer (SIR=1.43; 0.99-1.98) in Svidnik not observed Michalovce. Among females from Michalovce, but not Svidnik, there was an excess of cancer of the lip (SIR=2.54; 1.53-3.96), stomach (SIR=1.22; 1.02-1.44), and lung (SIR=1.17; 0.94-1.45); in contrast, there was an excess of kidney (SIR=1.61; 1.03-2.40) and thyroid (SIR=1.97; 1.12-3.20) cancer in Svidnik not observed in Michalovce. Taken together, these results raise the possibility that high environmental exposure to organochlorines in the Michalovce district may be associated with higher rates of certain cancers, particularly stomach and lung cancer.     

Diesel emissions in Vienna

The aerosol in a non-industrial town normally is dominated by emissions from vehicles. Whereas gasoline-powered cars normally only emit a small amount of particulates, the emission by diesel-powered cars is considerable. The aerosol particles produced by diesel engines consist of graphitic carbon (GC) with attached hydrocarbons (HCs) including also polyaromatic HCs. Therefore the diesel particles can be carcinogenic. Besides diesel vehicles, all other combustion processes are also a source for GC; thus source apportionment of diesel emissions to the GC in the town is difficult.A direct apportionment of diesel emissions has been made possible by marking all the diesel fuel used by the vehicles in Vienna by a normally not occurring and easily detectable substance. All emitted diesel particles thus were marked with the tracer and by analyzing the atmospheric samples for the marking substance we found that the mass concentrations of diesel particles in the atmosphere varied between 5 and 23 μg m⁻³. Busy streets and calm residential areas show less difference in mass concentration than expected. The deposition of diesel particles on the ground has been determined by collecting samples from the road surface. The concentration of the marking substance was below the detection limit before the marking period and a year after the period. During the period when marked diesel fuel was used, the concentrations of the diesel particles settling to the ground was 0.012–0.07 g g⁻¹ of collected dust.A positive correlation between the diesel vehicle density and the sampled mass of diesel vehicles exists. In Vienna we have a background diesel particle concentration of 11 μg m⁻³. This value increases by 5.5 μg m⁻³ per 500 diesel vehicles h⁻¹ passing near the sampling location.The mass fraction of diesel particles of the total aerosol mass varied between 12.2 and 33%; the higher values were found in more remote areas, since diesel particles apparently diffuse easily.Estimates of diesel particle concentration by emission inventory or by using lead concentrations as an indicator for vehicle emissions gave similar values to those obtained in this study.Using available cancer risk data and diesel particle concentration found in this study, 1–2.6 additional lung cancers per 100,000 persons yr⁻¹ breathing diesel emissions in the measured concentration the whole lifetime can be expected.