Comparison of Different Genotoxic Tests for Biological Monitoring of Coke Oven Workers. Preliminary Results

Chemical by-products of coke production are classified by IARC as carcinogenic in humans. Polycylic aromatic hydrocarbons (PAH) are the main compounds involved in carcinogenic and mutagenic activities of coke oven smokes, but many other compounds are present in emissions and could be involved in these activities. PAH analysis of the atmosphere indicated external contamination, but is not sufficient to evaluate the risk for exposed workers. The aim of this study was to evaluate relationship between atmospheric analysis of PAH and genotoxic markers in coke oven workers'white cells compared to controls. One hundred fifty-five exposed workers'samples were analyzed. They were selected in 5 coke production sites using a complete questionnaire allowing one to exclude all confounding factors. Two equal groups of smokers and nonsmokers were analysed. Analysis of chromosomal aberrations (CA), sister chromatid exchange (SCE), micronucleus (MN) and DNA-adduct formation using ³²P-postlabelling were performed on leucocytes. Each worker was equiped with an individual pump during the shift, for analysis of 16 PAH.

All markers were strongly modified by smoking habits. In smokers, CA, SCE and MN were not influenced by exposure to PAH. The number of DNA-adducts was increased with PAH concentration. In non smokers, we have observed an increaseof breaks / cells and of the percentage of cells with aberrations. Number of MN and SCE were unchanged. The number and the amount of DNA-adducts were strongly increased in exposed workers. DNA-adducts appear to be the best marker for genotoxic risk assessment.     

Health Assessment of Polycyclic Aromatic Hydrocarbon Mixtures: Current Practices and Future Directions

The U.S. EPA's Integrated Risk Information System (IRIS) program has initiated a health assessment for polycyclic aromatic hydrocarbon (PAH) mixtures. The IRIS program develops EPA consensus scientific positions on potential human health effects from chronic exposure to chemicals. Currently, the IRIS database contains health assessments for the toxic effects of exposure to coke oven emissions, creosote, diesel emissions, and 15 individual PAH compounds. As a whole, these assessments do not consider issues related to the environmental occurrence of PAH compounds as complex mixtures. Risk assessment of PAH mixtures has been hindered by a lack of information on the composition and toxicity of specific mixtures, the components that contribute most to toxicity, and the interactions and differences in mode of action between components. The state-of-the-science has advanced considerably in the past decade and will play a key role in the development of the health assessment. Consideration of these issues led to an EPA-sponsored Workshop on Approaches to PAH Health Assessment in October 2001. The current practices of the EPA regarding the health assessment of PAH compounds and future directions of the agency are discussed in this article.     

Spatial and Time Variation and Effect of Some Meteorological Parameters in Polycyclic Aromatic Hydrocarbons in Athens Greece

Abstract

The PAH concentrations determined on 650 samples of airborne particulates collected from four locations in the Athens area have been studied for two years starting in February 1984. The sampling sites covered both the center and the industrial area of the city. Higher values of PAH were found at the site located in the center of the city than at sites located in the industrial areas. The height of the sampling place has a negative effect on PAH concentrations. The mean yearly concentration values of benzo(a)pyrene varied between 1.8 and 4.0 ng m^?3 for the various sites and can be characterised as median levels. Higher PAH concentrations were found during winter months, while on Sundays the levels of PAH were lower. PAH concentrations increased during days with temperature inversions and when light winds from the Southwest direction prevailed. The main source of PAH in Athens seemed to be fuel burning either for central heating or industrial use in winter and for diesel powered vehicles in summer.     

Urban Runoff Contribution to Surface Sediment Accumulation for Polycyclic Aromatic Hydrocarbons in the Cotonou Lagoon,Benin

The carcinogenic and mutagenic properties of some polycyclic aromatic hydrocarbons (PAHs) and their widespread presence in the environment have led to many scientific investigations during the past three decades. In this study, surface sediments from six sampling sites in the Cotonou lagoon (three sites in the channel and three in Lake Nokoue) during the highest stormy season (May, June, and July) were used to assess the urban runoff contribution of PAH accumulation in this ecosystem. This assessment showed relatively high PAH loads (140-625 ng/g) during the rainy season and high inputs of organic materials (total organic carbon contents between 2.5 and 9.5% dry weight). Generally known as originating from different processes, PAHs detected in most of the Cotonou lagoon sampling sites were characterized by the predominance of the high-molecular-weight PAH over the low-molecular-weight PAH, which is an indicator of pyrolytic origin PAH inputs. PAH contamination in the Cotonou lagoon surface sediments was mainly from heavy urban traffic linked to the use of diesel vehicles and to the motorbike taxis proliferating across and around the city. Regression analysis carried out between total PAH concentration and total organic carbon contents showed, excluding the rural sampling site, a positive linear relationship for most samples ( R 2 = 0.9996), and confirmed the pyrogenic input of PAHs in the Cotonou lagoon. Mitigation measures were suggested to ameliorate the PAH pollution in the lagoon.     

POLYCYCLIC AROMATIC HYDROCARBONS (PAH) IN DANISH SMOKED FISH AND MEAT PRODUCTS

Twenty seven PAH were detected in 45 selected smoked food samples produced in Denmark, including mackerel, herring, trout, small sausages, salami, and bacon. The sum of PAH in smoked meat products ranged from 24 μg/kg for salami to 64 μg/kg in bacon, while those in fish products ranged from 22 μg/kg in smoked mackerel prepared in an electric oven to 1387 μg/kg in herring smoked by direct smoking. The concentration of benzo[a]pyrene for all sample types were below the maximum level of 5 μg/kg for smoked fish and meat set by the European Commission. Results from this survey confirm that the actual level of individual PAH in fish products is dependent on variables such as the type of wood used in the smoking process. Furthermore, the use of the benzo[a]pyrene approach for estimation of the carcinogenicity of PAH in food is confirmed. The Danish intake of benzo[a]pyrene from these smoked products is 2 to 4 ng/person/day.     

PHYSICO-CHEMICAL ARTEFACTS IN ATMOSPHERIC PAH DENUDER SAMPLING

Two annular diffusion denuder-filter samplers were operated concurrently to assess sampling artefacts arising from possible breakthrough of gas-phase PAH, blow-off of particle-bound PAH and degradation due to atmospheric ozone. The results of a field investigation held at Montelibretti (Rome, Italy) indicate that such artefacts are minimized or avoided when 6 h air samples are collected at 6 L min^?1 and an ozone scrubbing denuder is placed at the beginning of the sampling train. The partitioning of semi-volatile PAH followed closely that previously observed in downtown Rome but their absolute concentrations were up to an order of magnitude lower.     

Polycyclic aromatic hydrocarbons emitted by power stations,and influence of combustion conditions

Polycyclic aromatic hydrocarbons (PAH) were measured in the emissions of seven power stations. For the first time, all measurements were made with standard sampling and uniform analysis procedures. The influence of effective power of the station, nature of fuel (coal, oil, diesel oil) and kind of furnace was determined. The relations between PAH emission and excess oxygen in flue gas, NO_x concentration, calorific value and composition of the fuel and amount of ash were established. Very fast reactions, at high temperature, between PAH and gaseous pollutants are possible in the furnace or during the passage of flue gas through the stack. The gas-particle ratio of the PAH also depends on all combustion parameters. The PAH emitted are unburnt matter, numerous light compounds (with two or three rings) or heavy compounds or after demethylation of alkyl PAH. The impact of power stations on the amount of PAH in the atmosphere cannot exceed 5% in large cities.     

SIMULTANEOUS GC/MS ANALYSIS OF POLYCYCLIC AROMATIC HYDROCARBONS AND THEIR NITRATED DERIVATIVES IN ATMOSPHERIC PARTICULATE MATTER FROM WORKPLACES

Abstract

PAH are routinely analyzed using HPLC/FD. This technique is unsuitable for analyzing NPAH. This study aims at developing a reliable method, using GC/MS, and applying this technique to actual samples from small volumes of atmospheric particulate matter from workplaces. Mixtures of PAH and NPAH were separated by GC/MS and detected by electronic impact (EI) or negative ion chemical ionization (NICI). Analyses on twelve actual samples were thus carried out by sampling a small volume of atmosphere (≈0.5 m ³ ) from five different industrial workplaces. Samples displayed wide differences from one industrial workplace to another, and this can be explained by the specific methods applied. The PAH and NPAH concentrations also varied with time in the same industrial workplace. NPAH concentrations were not correlated with PAH concentrations, underscoring the complex chemical mechanisms involved in NPAH formation. PAH and NPAH formation appeared to be dependent on both industrial activities and uncontrolled physicochemical conditions.     

Accurate Determination of Moisture Content of Organic Soils Using the Oven Drying Method

The accuracy of moisture content values determined for organic soil using the oven drying method is dependent on the oven drying temperature. Some charring of the organic fraction occurs at the standard oven drying temperature of 110 ± 5°C; pore water remains in the soil when temperatures below 100°C are used. A new technique to determine the specific oven drying temperature that yields the correct value of the moisture content for organic soils is presented. Routine moisture content tests should be conducted at the standard oven drying temperature; moisture content values determined on the basis of the recommended oven drying temperature of 60°C include a larger error. A moisture content parameter is introduced to facilitate direct comparison of moisture content values calculated on the basis of different oven drying temperatures.     

Use of the Semipermeable Membrane Device (Spmd) to Sample Polycyclic Aromatic Hydrocarbon Pollution In A Lotic System

Abstract

Relative concentrations of aqueous polycyclic aromatic hydrocarbons (PAH) were investigated in an urban creek. Samples were obtained at five sites within a 600-m segment of the creek that is critical habitat for an endangered species of fish. the sampling technique entailed immersion of semipermeable membrane devices (SPMDs) in the water for intervals as long as 64 d. SPMDs are passive, in situ, mtegrative samplers of bioavailable (truly dissolved) PAH and other hydrophobic organic contaminants. Two point sources of PAH to the 600-m segment of the creek were differentiated. Aqueous concentrations were found to wane dramatically over the relatively short section of the creek between the point sources. All samples were almost devoid of alkyl-substituted PAH, indicating that the ultimate sources were probably of pyrogenic nature.     

Accurate Determination of Moisture Content of Organic Soils Using the Oven Drying Method

Abstract

The accuracy of moisture content values determined for organic soil using the oven drying method is dependent on the oven drying temperature. Some charring of the organic fraction occurs at the standard oven drying temperature of 110 ± 5°C; pore water remains in the soil when temperatures below 100°C are used. A new technique to determine the specific oven drying temperature that yields the correct value of the moisture content for organic soils is presented. Routine moisture content tests should be conducted at the standard oven drying temperature; moisture content values determined on the basis of the recommended oven drying temperature of 60°C include a larger error. A moisture content parameter is introduced to facilitate direct comparison of moisture content values calculated on the basis of different oven drying temperatures.     

Effect of vegetable oil addition on bioaccessibility and biodegradation of polycyclic aromatic hydrocarbons in historically contaminated soils

BACKGROUND: Bioaccessibility is often the limiting factor for the biodegradation of polycyclic aromatic hydrocarbons (PAH) in soils. The present study explores the potential of amending canola oil, an economically and ecologically attractive soil additive, for the enhancement of bioaccessibility and, in consequence, biodegradation of PAH in historically contaminated, bioaccessibility limited soils. RESULTS: The amendment of canola oil (1% and 5%, w/w) to contaminated soils increased the bioaccessibility and the subsequent biodegradation of PAH with up to four rings. Residual concentrations of pyrene and fluoranthene in oil‐treated soils were 38–53% lower compared to the unamended tests. The continuous removal of bioaccessible PAH with a passive sampling system confirmed that oil amendment indeed increased bioaccessibility, leading to a lower non‐accessible PAH fraction. Canola oil amendment did, by contrast, not increase the bioaccessibility of high molecular weight PAH, likely due to their strong binding to soil organic carbon compounds. CONCLUSION: Canola oil can be used efficiently in low concentrations to render PAH up to four rings accessible for biodegradation in historically contaminated soils. Contaminants remaining in soil after treatment may pose a significantly lowered environmental risk, as is indicated by the lack of mobilisation by a solubilising agent such as canola oil. Copyright © 2009 Society of Chemical Industry     

Force‐Free Patterning of Polyelectrolyte Multilayers under Solvent Assistance

Physical patterns were created on hydrated PSS/PDADMAC multilayers without using external force. A typical process was to put a PDMS stamp onto the wet and swollen multilayers, which were then put into an oven and maintained for a period of time to micromold the multilayers. The influence of molding temperature and time, multilayer thickness, solvent quality, and multilayer compositions on pattern formation were elucidated. Evolution of the patterns from double lines, double strips, and meniscus‐shaped ridges to high ridges was observed under all conditions, revealing that this is a universal principle for this process. Finally, patterns on PAA/PAH and PSS/PAH multilayers were also prepared at the optimal conditions, highlighting its wide generality on the multilayer patterning.

     

HTV硅橡胶生胶挥发分的快速测定

为了缩短测试甲基乙烯基硅橡胶生胶挥发分的时间,将常压恒温干燥箱烘烤改为真空干燥烘箱烘烤。考察了称样量、烘箱温度、烘烤时间、真空度对测试结果的影响,并与传统的电热恒温干燥箱法测试数据进行对照;验证了此法的精密度、再现性和稳定性。结果表明,较佳测试条件是:取样量为2.0~2.5 g、相对真空度(表压)为-0.09 MPa、烘箱温度150℃、恒温时间40 min,在此条件下测试的甲基乙烯基硅橡胶生胶挥发分数据与采用常规检测方法测得的数据比较吻合,精密度、再现性较好,且测试时间比常规检测方法缩短2 h。     

微波在动物胶法测磷矿石中硅含量的应用

动物胶凝聚重量法测定磷矿石中硅,先用微波炉碱熔分解试样,生成沉淀用玻璃砂芯坩埚过滤,再用微波炉恒重坩埚和沉淀,与经典方法对照,结果无明显差异。该方法简单准确,省时省电,具有一定实用价值。     

The sources of polycyclic aromatic compounds in diesel engine emissions

The application of a radiotracer technique to investigate the sources of polycyclic aromatic hydrocarbons (PAH) in diesel exhaust emissions is described. In separate experiments, ¹⁴C radiolabelled naphthalene, fluorene, fluoranthene and pyrene were each added to diesel fuel which was combusted in a 2L direct injection Perkins Prima diesel engine run at steady state under a series of speed (1000-3200 rpm) and load (20-80 N m) conditions. Each PAH was recovered in the exhaust emissions, using a novel sampling system, and its specific activity used to reveal the extent of its survival and pyrosynthesis of the PAH from other fuel fragments. Survival of the PAH varied from below detection limit for fluoranthene at low speed and load to 1.25% for fluorene at high speed and low load. For mid-speed and mid-load conditions, a linear relationship was observed between the extent to which individual PAH survived combustion and the energy level of the lowest unoccupied molecular orbital (LUMO) of the molecule calculated from Hückel molecular orbital theory. LUMO is an indirect parameter related to gas phase oxidation rates of PAH. Linearity was not so apparent at other speeds and loads. Resynthesis of the PAH varied from less than 0.1% for pyrene at mid-speed and mid-load to 4.93% for naphthalene at high-speed and high-load. Probable mechanisms for the production of some of the pyrosynthetic PAH were discussed.     

Distribution and Sources of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Sediments from the Northern Part of the Persian Gulf (Hormuzgan Province)

Sediments from the intertidal areas of Hormuzgan province in northern part of Persian Gulf (Iran) were investigated for the levels and possible sources of 15 polycyclic aromatic hydrocarbons (PAHs). Samples of sediments were collected from twelve sampling sites and analyzed for PAHs by gas chromatography–mass spectrometry (GC-MS). The results showed that the total concentrations of PAHs ranged from 765 to 1898 ng/g dry weight. Composition pattern in the sediment samples from 12 sampling sites was dominated by 4-ring PAH compounds. Molecular indices based on ratios of PAH concentrations were used to differentiate PAHs from pyrolitic, petrogenic and mixed origins. The results of study suggested that the main sources of PAHs in the sediment were mixed with pyrolitic and petrogenic inputs. According to the US sediments quality guidelines (SQGs) (ERL/ERM) sediments of the mentioned region did not show any ecotoxicological risk for benthic organisms.     

PAH Exposures of Nine Preschool Children

The exposures to 20 polycyclic aromatic hydrocarbons (PAH) of 9 children, ages 2–5 yr, were measured over 48 hr at day care and at home. Sampled media included indoor and outdoor air, floor dust, outdoor play area soil, hand surface, and solid and liquid food. Urine samples were collected for metabolite analysis. Diaries of the children's activities during the sampling period were also kept.

Significant positive correlations between media were found for total PAH in indoor air with floor dust (p<0.001), and for total PAH in outdoor air with floor dust (p<0.05). Also at the p<0.05 level, the B2 PAH (probable human carcinogens) were correlated in play area soil with outdoor air, and in outdoor with indoor air. Total PAH and B2 concentrations were correlated in play area soil and in floor dust (p<0.05).

The relative importance of the exposure pathways differed for total PAH and B2 PAH. For total PAH, which included both volatile and semi-volatile compounds, inhalation was most important, then dietary ingestion, then non-dietary ingestion. In contrast, for the B2 PAH only, non-dietary ingestion was most important, then dietary ingestion, and inhalation was least important.

Differences in the children's PAH exposures were small between day care and home, and also between children from low-income and from middle-income families.     

The Effect of Local Cooking Methods on Polycyclic Aromatic Hydrocarbons (PAHs) Contents in Beef,Goat Meat,and Pork as Potential Sources of Human Exposure in Kisumu City,Kenya

Roasted meat is known to be a major source of human exposure to PAHs. The contribution of direct-heat charcoal-roasted, electric- oven grilled, and shallow-pan fried meat to human exposure in Kisumu City was not known although the three modes of cooking meat are very prevalent. This study analyzed the concentrations of the PAHs in raw beef, goat meat, and pork, investigated the effect of direct-heat charcoal roasting, electric-oven grilling, and shallow-pan frying on these concentrations, and compared their concentration levels with international standards for foods in order to assess the potential risks to consumers. Samples were taken from three popular meat-roasting hotels within Kisumu City, Kenya. Extraction of PAHs was done using liquid-liquid partition after saponification with alcoholic potassium hydroxide followed by clean-up on a silica gel column and final analysis by gas chromatography-mass spectrometry (GC-MS). Roasting and shallow-pan frying introduced new PAHs and significantly (P ≤ 0.05) increased the concentrations of those existing in raw meat. Direct-heat charcoal roast beef had 5 new PAHs and a total mean PAH content of 17.88 μg/kg, compared with a mean of 1.39 μg/kg for raw beef, with the potent dibenz(a,h)anthracene also being detected. Direct-heat charcoal roasted goat meat had three new PAHs and a total mean PAH content of 4.77 μg/kg, compared with a mean of 2.13 μg/kg in raw meat, with the potent benzo(a)pyrene concentration being 8.84% of the total mean PAH. Fried pork had 7 new PAHs and a total mean PAH content of 3.47 μg/kg, compared with a mean total of 0.17 μg/kg, detected in the raw meat. Roast beef had the highest individual PAH concentration (5.03 μg/kg) and highest total PAHs concentration (17.88 μg/kg), both being higher than acceptable EU limits. The PAHs from local raw and cooked meat were characterized and quantified for the first time in Kisumu City and the study therefore provided the needed baseline data on PAHs in raw and cooked meat.     

SCP一体机在6.25m捣固焦炉中额定与极限推焦电流及炉墙负荷核算

针对SCP一体机在国内第一座6.25 m捣固焦炉的最适推焦力及推焦阻力国内尚无理论计算的情况,对6.25 m捣固焦炉生产中SCP一体机推焦电流进行了核算,并针对一体机推焦电流的大小对炉墙的负荷进行了预测,确定了电机额定电流263 A作为6.25 m捣固焦炉推焦极限电流,402 A作为极限推焦电流,不仅可以满足生产安全需求,而且可延长大型捣固焦炉的使用寿命。