Do the VOCs that evaporate from a heavily polluted river threaten the health of riparian residents?

To understand the potential threat of volatile organic compounds (VOCs) to the health of residents living close to a heavily polluted river, this study investigated the species and the concentration of VOCs evaporating from a river and surveyed the health condition of the nearby residents. Air samples were taken seasonally at the upstream, midstream, and downstream water surfaces of the river, and at different locations at certain distances from the river. These samples were analyzed qualitatively and quantitatively through gas chromatography and electron capture detector (GC/ECD) for chlorinated organic compounds, and through gas chromatography and flame ionization detector (GC/FID) for ordinary hydrocarbons. The health data obtained from valid health questionnaires of 908 residents were analyzed through Statistical Package for Social Science (SPSS) software. Twenty-six species of VOCs were identified in the environment adjacent the river, many of which are carcinogenic or believed to be carcinogenic to humans. However, results of this study shows that the VOCs evaporating from the polluted river have not been definitively identified as a major factor of cancer in the residents. However, the risk of suffering from certain chronic diseases may increase in residents living less than 225 m away from the river due to the high levels of evaporated VOCs. Residents living less than 225 m away from the river and with nearby specific industries are 3.130 times more at risk of suffering from chronic diseases than those with no nearby specific industries.     

黄河水源地“三致”物监测必要性与断面布设探讨

在河流污染物中，致癌物、致突变物、致畸形物（简称“三致”物）毒性最强，对人体健康威胁最大，据检测，在黄河干流兰州段，包头段和郑州段等河段已存在一定程度的“三致”物污染，就尽早开展饮用水水源地“三致”毒物污染监测，根据沿黄城市的分布情况及河段污染特点，可在兰州市包兰桥断面，包头市镫口断面、郑州市花园断面及河口段利津断面首先开展监测工作。     

The potential of sphingomyelin as a chemopreventive agent in AOM-induced colon cancer model: wild-type and p53+/- mice

A protective effect of sphingolipids on colorectal cancer (CRC) has been reported in certain mouse strains. It is unknown if sphingolipids are protective in a p53 deficiency mouse model of CRC. This study investigated the effect of sphingomyelin (SM) on intestinal sphingomyelinase (SMase) activity, colonic epithelial biology and azoxymethane (AOM)-induced CRC. Groups of wild-type (C57BL/6J) and p53+/- mice were fed 0.1% SM diet for 4 wk, administered a single AOM injection and then killed 6 h later to measure apoptosis and proliferation. Separately, both mouse types were fed 0.05% SM diet, administered three AOM injections and killed 33-38 wk later to measure tumour formation. SM significantly increased SMase activity and reduced proliferation (p < 0.05) in wild-type and p53+/- mice. SM did not regulate baseline apoptosis, apoptotic response to AOM or apoptosis in tumours, nor did it restore defective apoptosis in p53+/- mice. There was a nonsignificant trend to reduced tumour incidence with SM in wild-type (p = 0.15) and p53+/- (p = 0.12) mice. In conclusion, while increasing intestinal SMase activity and suppressing proliferation, SM did not promote any form of apoptosis and failed to achieve significant protection in these mice. Further investigation to understand the variable effect of SM in preventing CRC is warranted.     

AES中的二(啞)烷的生成和控制

二(啞)烷被国际癌症研究机构(IARC)定为2B类致癌物质,即对人类的潜在致癌性较小.二(啞)烷是生产AES的副产物,可以通过加强原料含水控制、调整气体浓度、调整反应物质的量比、控制反应温度和时间以及精密工艺控制等手段来降低其在AES产品中的含量.     

Polycyclic Aromatic Hydrocarbons Determination in Grilled Beef and Chicken

ABSTRACT

Polycyclic aromatic hydrocarbons (PAHs) are principally formed as a result of thermal treatment of food, especially grilling or barbecuing. In the present study, two types of Iranian popular grilled beef and chicken dishes (kebab) were analyzed for toxic PAHs, i.e., naphthalene, fluoranthene, phenanthtrene, anthracene, pyrene, and benzo(a)pyrene applying GC/MS. The differences in PAHs concentrations among grilled beef and chicken (kebab koobide and juje kebab) were found to be significant (p < 0.05), ranging from 0.29 to 21.95 ng·g^?1. Benzo(a)pyrene was found in nearly all samples; the maximum concentration of total PAHs was 21.95 ng·g^?1 found in grilled beef (koobide Khalij fars) and the lowest was 0.29 ng·g^?1 in grilled chicken (juje kebab) of Sahel restaurant.     

Determination of ethyl carbamate in some fermented Korean foods and beverages

Ethyl carbamate has been associated with cancer for several decades. It is mainly found in fermented foods and beverages. In view of the importance of fermented foods in the Korean diet and the significant level of ethyl carbamate expected, we determined ethyl carbamate concentrations in some of the staple food items and estimated the daily intake for the Korean population. Ethyl carbamate in commercial samples of kimchi, soy sauce, vinegar, soybean paste, and alcoholic beverages were determined by gas chromatography-mass spectrometry/selective ion monitoring (GC-MS/SIM). Homemade soy sauce and kimchi were also analysed. The maximum ethyl carbamate concentrations observed were 73 mu g/kg in soy sauce, 7.9 mu g/kg in soybean paste, 2.5 mu g/l in vinegar, 16.2 mu g/kg in kimchi and 15.4 mu/l in Korean traditional alcoholic beverages. Combining these values with the average daily food intake data, we estimated that the maximum daily exposure of Korean population to ethyl carbamate is 2.8 mu g/day, which is not a negligible amount considering the 'virtually safe dose' derived by animal experiment ranges between 1.2 and 4.8 mu g/day. It would be desirable to closely monitor ethyl carbamate levels in Korean foods and to find ways to reduce the daily intake.     

Furan in heat‐treated foods: Formation,exposure, toxicity,and aspects of risk assessment

Furan is formed in a variety of heat‐treated foods through thermal degradation of natural food constituents. Relatively high levels of furan contamination are found in ground roasted coffee, instant coffee, and processed baby foods. European exposure estimates suggest that mean dietary exposure to furan may be as high as 1.23 and 1.01 μg/kg bw/day for adults and 3‐ to 12‐month‐old infants, respectively. Furan is a potent hepatotoxin and hepatocarcinogen in rodents, causing hepatocellular adenomas and carcinomas in rats and mice, and high incidences of cholangiocarcinomas in rats at doses ≥2 mg/kg bw. There is therefore a relatively low margin of exposure between estimated human exposure and doses that cause a high tumor incidence in rodents. Since a genotoxic mode of action cannot be excluded for furan‐induced tumor formation, the present exposures may indicate a risk to human health and need for mitigation. This review summarizes the current knowledge on mechanisms of furan formation in food, human dietary exposure to furan, and furan toxicity, and highlights the need to establish the risk resulting from the genotoxic and carcinogenic properties of furan at doses lower than 2 mg/kg bw.     

Contribution of selected foods to acrylamide intake by a population of Brazilian adolescents

Acrylamide dietary intakes from selected foods are estimated in this work for Brazilian adolescents from São Paulo State. The exposure assessment was carried out by combining levels of acrylamide in foods determined analytically by an accredited LC-MS/MS method, with individual food consumption data, using a deterministic approach. Data on food consumption were generated using 24 h recall applied to 578 individuals aged from 11 to 17 years, between July and August 2001. The mean and maximum acrylamide intakes were estimated to be 0.12 and 1.92 μg/kg bw/day, respectively. At 50th, 95th and 97.5th percentiles, the average intakes were 0.04, 0.55 and 0.77 μg/kg bw/day, respectively. Boys presented exposure levels lower than girls, while the acrylamide intake by younger adolescents (11-14 years) was higher compared to the older group (15-17 years). The foods that contributed most to acrylamide exposure were French fries, French bread, water and salt biscuit and coffee.     

Carcinogen specific dosimetry model for passive smokers of various ages

Studies indicate that being exposed to second hand smoke increases the chance of developing lung cancer. Understanding the deposition of carcinogenic particles present in second hand smoke is necessary to understand the development of specific histologic type cancers. In this study, a deposition model is presented for subjects of various ages exposed to sidestream smoke. The model included particle dynamics of coagulation, hygroscopic growth, charge and cloud behavior. Concentrations were varied from the maximum measured indoor concentrations (10(6) particles/cm3) to what would be expected from wisps of smoke (10(8) particles/cm3). Model results agreed well with experimental data taken from human subject deposition measurements (four studies). The model results were used to determine the dose intensity (dose per unit airway surface area) of Benzo[a]pyrene (BaP) in the respiratory tract for subjects of various ages. Model predictions for BaP surface concentration on the airway walls paralleled incident rates of tumors by location in the upper tracheobronchial region. Mass deposition efficiency was found to be larger for younger subjects, consistent with diffusion being the predominant mechanism for this particle size range. However, the actual dose intensity of BaP was found to be smaller for children than adults. This occurred due to the predominant effect of the smaller initial inhaled mass for children resulting from smaller tidal volumes. The resulting model is a useful tool to predict carcinogen specific particle deposition.     

BIOALKYLATION OF BENZ(A)ANTHRACENE: IMPLICATIONS FOR CARCINOGENESIS

Previous studies on the metabolic activation of unsubstituted polycyclic aromatic hydrocarbons have largely focused on the formation of oxidation products as a result of reaction of the parent hydrocarbon with microsomal enzymes. These products of reaction have included both epoxide as well as a diol epoxide metabolites. In addition, formation of quinones as well as hydroxyl substituted derivatives of various polycyclic aromatic hydrocarbons have been investigated as metabolic endpoints. Several studies have taken place illustrating the formation of these metabolites, as well as the formation of biologically relevant adducts in a variety of animal models as well as cell culture preparations. Although these metabolic products have been widely characterized and studied in a variety of systems, there have been limited studies characterizing the formation of methyl substituted derivatives of unsubstituted aromatic hydrocarbons, and the subsequent formation of hydroxyalkyl derivatives of various compounds. The present study investigates the formation of both alkyl and hydroxyalkyl substituted derivatives of the unsubstituted polycyclic aromatic hydrocarbon benz(a)anthracene in preparations of rat liver cytosol fortified with S-adenosyl-L-methionine. The results demonstrate that methylated derivatives are formed as metabolic products, and that the identity of these products are both the 7-methybenz(a)anthracene and 7,12-dimethylbenz(a)anthracene. These results confirm that aromatic hydrocarbons undergo biological substitution reactions at specific centers of reactivity of the unsubstituted molecule yielding bioalkylated derivatives.