Abstract  OBJECTIVES: Consolidation of epidemiological data on pancreatic cancer and worksite exposures. METHODS: Publications during 1969-98 were surveyed. Studies without verified exposures were excluded. Meta-analyses were conducted on data from 92 studies covering 161 populations, with results for 23 agents or groups of agents. With a standard format, five epidemiologists extracted risk estimates and variables of the structure and quality of each study. The extracted data were centrally checked. Random meta-models were applied. RESULTS: Based on 20 populations, exposure to chlorinated hydrocarbon (CHC) solvents and related compounds was associated with a meta-risk ratio (MRR) of 1.4 (95% confidence interval (95% CI) 1.0 to 1.8). Nickel and nickel compounds were considered in four populations (1.9; 1.2 to 3.2). Excesses were found also for chromium and chromium compounds (1.4; 0.9 to 2.3), polycyclic aromatic hydrocarbons (PAHs) (1.5; 0.9 to 2.5), organochlorine insecticides (1.5; 0.6 to 3.7), silica dust (1.4; 0.9 to 2.0), and aliphatic and alicyclic hydrocarbon solvents (1.3; 0.8 to 2.8). Evidence on pancreatic carcinogenicity was weak or non-positive for the following agents: acrylonitrile (1.1; 0.0 to 6.2); arsenic (1.0; 0.6 to 1.5); asbestos (1.1; 0.9 to 1.5); diesel engine exhaust (1.0; 0.9 to 1.3); electromagnetic fields (1.1; 0.8 to 1.4); formaldehyde (0. 8; 0.5 to 1.0); flour dust (1.1; 0.3 to 3.2); cadmium and cadmium compounds (0.7; 0.4 to 1.4); gasoline (1.0; 0.8 to 1.2); herbicides (1.0; 0.8 to 1.3); iron and iron compounds (1.3; 0.7 to 2.5); lead and lead compounds (1.1; 0.8 to 1.5); man-made vitreous fibres (1.0; 0.6 to 1.6); oil mist (0.9; 0.8 to 1.0); and wood dust (1.1; 0.9 to 2.5). The occupational aetiological fraction of pancreatic cancer was estimated at 12%. In a subpopulation exposed to CHC solvents and related compounds, it was 29%; to chromium and chromium compounds, 23%; to nickel and nickel compounds, 47%; to insecticides, 33%; and to PAHs, 33%. CONCLUSION: Occupational exposures may increase risk of pancreatic cancer. High quality studies are called for on interactions between occupational, environmental, and lifestyle factors as well as interactions between genes and the environment.

Abstract  A gas chromatography/ion trap mass spectrometry method was developed for analysis of organochlorine pesticides (OCPs) in coral samples, which were extracted with accelerated solvent extraction (ASE) and cleaned up on a sulfuric acid-modified silica gel column. The optimal ASE conditions were found to be 100°C and 2000 psi, with a mixture of acetone and methylene chloride (1:1, v/v). The target analytes include hexachlorocyclohexanes (HCHs, specifically, α-, β-, γ-, and δ-HCH isomers), heptachlor, and hexachlorobenzene (HCB), o,p′-, p,p′-dichlorodiphenyltrichloroethane ( o,p′-, p,p′-DDT), o,p′-, p,p′-dichlorodiphenyl-dichloroethylene ( o,p′-, p,p′-DDE), and o,p′-, p,p′-dichlorodiphenyldichloroethane ( o,p′-, p,p′-DDD). Standard sand samples were used as an alternative matrix spiked with OCP standards to determine the method precision and accuracy. Average recoveries of OCPs ranged from 82% to 102%, with relative standard deviations (RSDs) of 3%–6%, at a level of 10 ng/g and from 50% to 68%, with RSDs of 13%–19% at a level of 2 ng/g. The developed method was applied for analysis of OCPs in coral samples collected from Tern Island and Bikini Atoll in the Pacific Ocean. The concentrations of HCB were 7–26 pg/g dry weight in the samples from Bikini Atoll and 3–45 pg/g in those from Tern Island, and heptachlor concentrations were 208–2200 and 44–104 pg/g in the coral samples from Bikini Atoll and Tern Island, respectively. ∑HCH (sum of α-, β-, γ-, and δ-HCH) were 8–82 pg/g in Bikini Atoll coral and 86–629 pg/g in Tern island coral, and ∑DDT (sum of o,p′-, p,p′-DDD, o,p′-, p,p′-DDE, and o,p′- p,p′-DDT) were 80–212 pg/g in Bikini Atoll coral and 593–3165 pg/g in Tern Island coral. The results suggest that coral is a viable indicator species for... ABSTRACT FROM AUTHOR Copyright of Archives of Environmental Contamination & Toxicology is the property of Springer Science & Business Media B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts)

Abstract  Environmental quality standards (EQSs) have been established as desirable levels to be maintained for protection of human health and the conservation of the living environment by Basic Environment Law. EQSs in ambient air had been set for 10 substances (sulfur dioxide (SO(2)), carbon monoxide (CO), suspended particulate matter (SPM), nitrogen dioxide (NO(2)) and photochemical oxidants (Ox), benzene, tetrachloroethylene, trichloroethylene, dioxins and dichloromethane) and guideline values for 7 (acrylonitorile, vinyl chloride monomer, mercury, nickel compounds, 1,3-butadiene, chloroform and 1,2-dichloromethane) in Japan by 2009. EQSs for the classical (or traditional) air pollutants, SO(2), CO, SPM, NO(2) and Ox, were set according to the minimal requirement to protect human health, based on evidence from epidemiological studies conducted before the 1970s. In 1996, the Central Environment Council designated substances which may be hazardous air pollutants and substances requiring priority action, and adopted the concept of risk assessment to set EQSs and guideline values. A life-long risk level (virtually safe dose) of 10(-5) was used to set EQS for benzene, and guideline values for vinyl chloride monomer, nickel compounds, and 1,3-butadiene. EQSs for trichloroethylene, tetrachloroethylene and dichloromethane, and guideline values for acrylonitorile and mercury were set using uncertain factors and lowest observed adverse effect (LOAEL)/no observed adverse effect level (NOAEL). The results of animal experiments were utilized to set guideline values for chloroform and 1,2-dichloroethane. The benchmark approach and human equivalent concentration (HEC) were adopted for 1,2-dichloroethane. The history of setting EQSs and guideline values for hazardous air pollutants is one of adopting new concepts into risk assessment.

Abstract  Samples of mother's milk were collected from Bayonne, NJ; Jersey City, NJ; Pittsburgh, PA; Baton Rouge, LA; and Charleston, WV, and analyzed for volatile (purgeables) and semivolatile (extractable) organics using glass capillary gas chromatography/mass spectrometry/computer. In the volatile fraction, 26 halogenated hydrocarbons, 17 aldehydes, 20 ketones, 11 alcohols, 2 acids, 3 ethers, 1 epoxide, 14 furans, 26 other oxygenated compounds, 4 sulfur-containing compounds, 7 nitrogen-containing compounds, 13 alkanes, 12 alkenes, 7 alkynes, 11 cyclic hydrocarbons, and 15 aromatics were found, including major peaks for hexanal, limonene, dichlorobenzene, and some esters. The levels of dichlorobenzene appeared to be significantly higher in the samples from Jersey City and Bayonne than in samples from other sites. Jersey City samples also appeared to have significantly higher levels of tetrachloroethylene. Charleston and Jersey City samples appeared to have significantly higher levels of chloroform; however, chloroform was observed in the blanks at about 20% of that in the samples. Due to the small sample size and lack of control over the solicitation of sample donors, the data cannot be used to extrapolate to the general population. Fewer semivolatile compounds of interest were found. Polychlorinated naphthalenes, polybrominated biphenyls, chlorinated phenols, and other compounds were specifically sought and not detected (limit of detection about 20-100 ng/mL milk). Polychlorinated biphenyls (PCBs) and DDE were found.

Abstract  In conducting reviews or meta-analyses, epidemiologists frequently must reconcile conflicting results. This paper addresses heterogeneity in nonexperimental studies. The emphasis is on simple exploratory methods rather than formal approaches. Five examples illustrate how quantitative concordance among studies is possible, even when measured effects appear discrepant. The examples concern ethylene oxide and leukemias, methylene chloride and liver cancer, saccharin and bladder cancer, prenatal lead exposure and birthweight, and aspirin and bleeding tendencies in labor and delivery. Data examined here indicate that differences in dose levels frequently explain heterogeneous effect measures, often outweighing other sources of variability among studies. We present simple methods for combining dose information from the study of interest with dose-response data from other epidemiologic studies or animal studies to derive plausible hypothesized effect levels. These plausible effect sizes are the measures of association that would be predicted, for the actual exposures, by extrapolating from other studies with possibly differing exposure levels. Post hoc power calculations and comparisons of confidence intervals for overlap to reconcile "positive" and "null" studies may be misleading, since these approaches assume a uniform true association obscured by random fluctuations only. Whenever it can be estimated, a plausible effect size should be the starting point to assess findings of either positive or null studies. Without such calculations, comparisons among conflicting studies may not be meaningful.

Abstract  The public depends on competent risk assessment from the federal government and the scientific community to grapple with the threat of pollution. When risk reports turn out to be overblown--or when risks are overlooked--public skepticism abounds. This comprehensive and readable book explores how the U.S. Environmental Protection Agency (EPA) can improve its risk assessment practices, with a focus on implementation of the 1990 Clean Air Act Amendments. With a wealth of detailed information, pertinent examples, and revealing analysis, the volume explores the "default option" and other basic concepts. It offers two views of EPA operations: The first examines how EPA currently assesses exposure to hazardous air pollutants, evaluates the toxicity of a substance, and characterizes the risk to the public. The second, more holistic, view explores how EPA can improve in several critical areas of risk assessment by focusing on cross-cutting themes and incorporating more scientific judgment. This comprehensive volume will be important to the EPA and other agencies, risk managers, environmental advocates, scientists, faculty, students, and concerned individuals.

Abstract  #A study of chloroacetates in snow, firm and glacier ice was undertaken to determine how widespread such compounds are in precipitation and to elucidate the possible involvement of anthropogenic and natural sources. Samples of snow were collected in remote areas, including Antarctica, the Russian tundra and northern Scandinavia, and at a few more populated sites. Glacier ice was sampled at two sites in northern Sweden, and firn from Antarctica was obtained from an archived ice core. Chemical analysis of the collected samples showed that mono-, di- and trichloroacetate were prevalent in all investigated regions, and concentrations of the respective compounds at remote sites normally ranged from 10 to 100 ng/L. The levels found were too high to be explained by direct anthropogenic emissions of chloroacetic acids or any of their salts. Furthermore, it was difficult to trace the nearly ubiquitous occurrence of all three chloroacetates to suggested anthropogenic precursors, such as 1,1,1-trichloroethane, trichloroethene and tetrachloroethene. The presence of mono-, di- and trichloroacetate in glacier ice from northern Sweden and in firn representing the past 100 years of snow accumulation in Antarctica strongly indicates that chloroacetates may occur naturally in precipitation.

Abstract  Methods of environmental and biological monitoring were applied in order to evaluate exposure to methylene chloride in workers operating in a factory where this substance was used as a solvent. For the measurement of methylene chloride in environmental concentration, the ambient air was sampled by using personal passive dosimeters. The activated charcoal was desorbed with CS2 and injected into a gas chromatograph connected with a mass spectrometer. The biological monitoring of exposed workers was performed by determining the concentration of CO in alveolar air (CA, ppm) and methylene chloride in urine (Cu, mu/L). Immediately after the end of the exposure, a urine sample was collected avoiding solvent loss and using gas-tight samplers. Excretion level in urine was determined by using headspace gas chromatography linked to a mass spectrometer. The CO was determined at the end of the shift by using a portable instrument. A group of 20 workers (12 smokers and 8 nonsmokers) in the manufacturing plant were monitored. No significant correlation was observed among the CO of all subjects and the concentration of methylene chloride in ambient air. When those workers who smoked were removed from the analysis, a correlation between the methylene chloride concentration in air and the CO concentration in alveolar air was found. Significant linear correlation was found between the environmental concentration of methylene chloride in the breathing zone and methylene chloride concentration in urine.

Abstract  The major aspects that must be considered in studies of the health effects of environmental pollutants are: the direct damage due to the exposure, the role of pre-existing disease, and effects of the exposure on the response to secondary stresses. In experimental studies at concentrations of air pollutants found in urban environments frank toxicological responses are rarely observed. However, exposure to a secondary stress, i.e. respiratory challenge with infectious bacteria, can exacerbate the response of the experimental host. Changes in the resistance to respiratory infections provide a highly sensitive experimental animal model system, which is increasingly used in studies of health effects of air pollutants. This model indicates the impairment of the basic defense mechanisms of the respiratory system by the combined exposure to low concentrations of pollutants and the superimposed bacterial infection. Changes in the resistance to respiratory infections were studied in various species of laboratory animals. S. pyogenes and K. pneumoniae are the bacteria of choice to induce the pulmonary infection. Included in the studies are short-term single and multiple exposures as well as long-term exposures to gaseous pollutants such as O3 and NO2 and particulate pollutants such as sulfates and nitrates. Changes in the resistance are measured as excess mortalities and reduced survival time as compared to those in infected animals not exposed to the pollutants. Other parameters measured ranged from changes in the immune response to changes in retention rates of bacteria in lungs.

Abstract  Inhalation of low concentrations (75 and 150 ppm) of carbon monoxide (CO) by pregnant rats from days 0 to 20 of gestation leads to alterations in habituation and working memory in young adult male offspring subjected to the novel exploration object test. In particular, lack of habituation upon the second presentation of the objects and failure in the ability to discriminate between the novel and the familiar object were found in CO (75 and 150 ppm)-exposed offspring. These alterations were not accompanied by changes in spontaneous motor activity (open field test). The subtle behavioral deficits observed in the present study have been produced by prenatal exposure to CO levels resulting in maternal blood carboxyhaemoglobin (HbCO) concentrations equivalent to those observed in human cigarette smokers.

Abstract  A new system has been developed to determine enzyme activities of glutathione transferase theta (GSTT1-1) based on radiometric product detection resulting from the enzymic reaction of methyl chloride with 35S-labelled glutathione. In principle, the method is universally applicable for determination-of glutathione transferase activities towards a multiplicity of substrates. The method distinguishes between erythrocyte GSTT1-1 activities of human 'non-conjugators', 'low conjugators' and 'high conjugators'. Application to cytosol preparations of livers and kidneys of male and female Fischer 344 and B6C3F1 mice reveals differential GSTT1-1 activities in hepatic and renal tissues. These ought to be considered in species-specific modellings of organ toxicities of chlorinated hydrocarbons.

Abstract  HEEP COPYRIGHT: BIOL ABS. Well-controlled experimental exposures to methylene chloride vapor lasting for 2 or 4 hr were performed in human beings and dogs. The exposure concentrations ranged from 100 to 1000 ppm in the dogs and from 100 to 200 ppm in man. Serial breath and blood curves from both species were directly proportional to the magnitude of exposure. The average 24-hr urinary excretions of methylene chloride for the 100- and 200- ppm exposures in man were approximately 23 mug and 82 mug, respectively. During comparable exposures, the dog absorbed substantially more methylene chloride vapor than man. Prolonging the exposure from 2 to 4 hr did not result in a substantial increase in solvent absorption. It is possible to make accurate extrapolations to human exposures from animal experiments provided the appropriate attention is given to factors such as the exposure duration, the time of collection after the exposure, the extent of metabolic involvement and kinetic parameters. In such extrapolations, it is sometimes necessary to correct the experimental die-away curves because of changes in muscular exercise during the exposure.

Abstract  Data were obtained from the exposure of eleven men to dichloromethane concentrations of 50, 100, 250, and 500 ppm, 1,3 or 7.5 hours per day, for up to five successive days and from the exposure of nine women to 250 ppm on a similar schedule. Breath concentrations of the solvent following exposure were related mathematically to exposure parameters as were blood concentrations of the metabolite, carbon monoxide (as carboxyhemoglobin percentage saturation elevations). The resulting emprical equations can be used to predict the consequences of many industrial and non-industrial exposure situations.

Abstract  The developmental expression of the alpha, mu and pi class glutathione S-transferases has been defined in human liver using radioimmunoassay and immunohistochemistry. Expression of alpha and mu class isoenzymes increased significantly at birth, while that of the pi isoenzyme declined during the first trimester. Mu-class isoenzymes (GST1 1, GST1 2, GST1 2-1) were expressed in hepatocytes but not in other liver cell types.

Abstract  There has been much discussion in recent years regarding the most appropriate follow-up testing in vivo when positive results are obtained in vitro but the in vivo micronucleus (MN) test (traditionally the most widely-used test) is negative. Not all rodent carcinogens give positive results in the micronucleus test, and so it has been common practice to include a second in vivo assay such as the unscheduled DNA synthesis (UDS) test. This has proved useful but is usually limited to analysis of rodent (usually rat) liver. With the increased evaluation and use of other in vivo assays, e.g. for transgenic mutations (TG) and DNA damage (Comet assay) it was important to investigate their usefulness. We therefore examined the published in vivo UDS, TG and Comet-assay results for 67 carcinogens that were negative or equivocal in the micronucleus test. Between 30 and 41 chemicals were evaluated in each of the three in vivo tests, with some overlap. In general, the UDS test was disappointing and gave positive results with <20% of these carcinogens, some of which induced tumours in rat liver and produced DNA adducts in vivo. The TG assay gave positive responses with >50% of the carcinogens, but the Comet assay detected almost 90% of the micronucleus-negative or equivocal carcinogens. This pattern of results was virtually unchanged when the in vitro profile (gene mutagen or clastogen) was taken into account. High sensitivity (ability to detect carcinogens as positive) is only really useful when the specificity (ability to give negative results with non-carcinogens) is also high. Based on small numbers of publications with non-carcinogens, the TG and Comet assays gave negative results with non-carcinogens on 69 and 78% of occasions, respectively. Although further evaluation of the Comet and TG assays, particularly with non-carcinogens, is needed, these data suggest that they both should play a more prominent role in regulatory testing strategies than the UDS test.

Abstract  Toxicokinetics is the study of kinetics of absorption, distribution, metabolism, and excretion of a xenobiotic under the conditions of toxicity evaluation. Conventional toxicokinetics uses the hypothetical compartments, and the model is composed of rate equations that describe the time course of drug and chemical disposition. The utility of toxicokinetics in toxicity evaluation and interpretation of animal toxicology data is emerging as an important tool in product discovery and development. With implementation of the International Conference on Harmonization (ICH) guidelines on systemic exposure and dose selection, toxicokinetics have been integrated in routine toxicity evaluations. Although traditional compartmental/noncompartmental models are generally adequate for assessing systemic exposure, they are unable to the predict time course of drug disposition in target tissues and often fail to relate systemic drug levels to a biological response. Physiologically based toxicokinetic (PB-TK) models address this deficiency of traditional compartmental models. PB-TK models are the kinetic models of the uptake and disposition of chemicals based on rates of biochemical reactions, physiological and anatomical characteristics. These models, when developed appropriately, can predict target organ drug distribution in different species under variety of conditions. This minireview discusses the basic principles, and applications of traditional compartmental toxicokinetic and physiologically based toxicokinetics (PB-TK) models in drug development and risk assessment. Special emphasis will be placed on discussion related to interpretation of the ICH guidelines related to toxicokinetics and the utility of toxicokinetics data in dose selection for toxicity and carcinogenicity studies. The utility of PB-TK models in risk assessment of methylene chloride, vinyl chloride, retinoic acid, dioxin, and inhaled organic esters is discussed.

Abstract  By using physiologically based pharmacokinetic (PBPK) modeling coupled with Monte Carlo simulation, the interindividual variability in the concentrations of chemicals in a worker's exhaled breath and urine were estimated and compared with existing biological exposure indices (BEIs). The PBPK model simulated an exposure regimen similar to a typical workday, while exposure concentrations were set to equal the ambient threshold limit values (TLVs) of six industrial solvents (benzene, chloroform, carbon tetrachloride, methylene chloride, methyl chloroform, and trichloroethylene). Based on model predictions incorporating interindividual variability, the percentage of population protected was derived using TLVs as the basis for worker protection. Results showed that current BEIs may not protect the majority or all of the workers in an occupational setting. For instance, current end-expired air indices for benzene and methyl chloroform protect 95% and less than 10% of the worker population, respectively. Urinary metabolite concentrations for benzene, methyl chloroform, and trichloroethylene were also estimated. The current BEI recommendation for phenol metabolite concentration at the end-of-shift sampling interval was estimated to protect 68% of the worker population, while trichloroacetic acid (TCAA) and trichloroethanol (TCOH) concentrations for methyl chloroform exposure were estimated to protect 54% and 97%, respectively. The recommended concentration of TCAA in urine as a determinant of trichloroethylene exposure protects an estimated 84% of the workers. Although many of the existing BEIs considered appear to protect a majority of the worker population, an inconsistent proportion of the population is protected. The information presented in this study may provide a new approach for administrative decisions establishing BEIs and allow uniform application of biological monitoring among different chemicals.

Abstract  Organophosphate (OP) exposure can be lethal at high doses while lower doses may impair performance of critical tasks. The ability to predict such effects for realistic exposure scenarios would greatly improve OP risk assessment. To this end, a physiologically based model for diisopropylfluorophosphate (DFP) pharmacokinetics and acetylcholinesterase (AChE) inhibition was developed. DFP tissue/blood partition coefficients, rates of DFP hydrolysis by esterases, and DFP-esterase bimolecular inhibition rate constants were determined in rat tissue homogenates. Other model parameters were scaled for rats and mice using standard allometric relationships. These DFP-specific parameter values were used with the model to simulate pharmacokinetic data from mice and rats. Literature data were used for model validation. DFP concentrations in mouse plasma and brain, as well as AChE inhibition and AChE resynthesis data, were successfully simulated for a single iv injection. Effects of repeated, subcutaneous DFP dosing on AChE activity in rat plasma and brain were also well simulated except for an apparent decrease in basal AChE activity in the brain which persisted 35 days after the last dose. The psychologically based pharmacokinetic (PBPK) model parameter values specific for DFP in humans, for example, tissue/blood partition coefficients, enzymatic and nonenzymatic DFP hydrolysis rates, and bimolecular inhibition rate constants for target enzymes were scaled from rodent data or obtained from the literature. Good agreement was obtained between model predictions and human exposure data on the inhibition of red blood cell AChE and plasma butyrylcholinesterase after an intramuscular injection of 33 micrograms/kg DFP and at 24 hr after acute doses of DFP (10-54 micrograms/kg), as well as for repeated DFP exposures.(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract  Multiwalled carbon nanotubes (MWCNTs) were synthesized by catalytic chemical vapor deposition and functionalized by oxidation with potassium permanganate at room temperature using a phase transfer catalyst, methyl trioctyl ammonium chloride as a dispersion agent. The functionalized nanotubes were characterized by Fourier transform infrared spectroscopy and thermogravimetry. Sonication was used to assist their dispersion in dichloromethane and the resulting suspension was added dropwise to a stirred polyvinyl alcohol aqueous solution and spongy microspheres were formed. SEM showed that the microspheres consisted of loosely entangled MWCNTs that had diameters in the range 50-150 mu m. The microspheres may be useful for lightweight energy absorbing coatings, catalyst and electronics applications.

Abstract  The separation of phenol from micellar solutions using micellar-enhanced ultrafiltration (MEUF) with polyether sulfone membrane was studied. Anionic sodium dodecylulfate (SDS), nonionic triton X-100 (TX-100) and three cationic surfactants, cetyl trimethyl ammonium bromide (CTAB), octadecyldimethylammonium bromide (OTAB) as well as cetylpyridinium chloride (CPC) were used. Several important parameters including distribution coefficient (D), concentration of phenol dissolved in the micelles (O-m) and concentration of surfactant in micelle phase (S-m) were determined to evaluate separation efficiency of phenol from various surfactant micelles with different hydrophilic head group and hydrophobic tail length. It was found that the rejection and D of phenol examined with CTAB micelles were the highest, while that with TX-100 were lower than SDS at feed surfactant concentration of 10 mM. The rejection and D of phenol as well as O-m with three cationic surfactants could be ranked as follows: OTAB > CTAB > CPC, which was contrary to the permeate flux. The rejections of three surfactants were extremely similar with the range of feed surfactant concentration from 1 mM to 30 mM, and S-m examined with OTAB and CPC was higher than that with CTAB. Crown Copyright (c) 2012 Published by Elsevier B.V. All rights reserved.

Abstract  Air toxics from the industrial wastewater treatment plants (IWTPs) impose serious health concerns on its surrounding residential neighborhoods. To address such health concerns, one of the key challenges is to quantify the air emissions from the IWTPs. The objective here is to characterize the air emissions from the IWTPs and quantify its associated uncertainty. An IWTP receiving the wastewaters from an airplane maintenance facility is used for illustration with focus on the quantification of air emissions for benzyl alcohol, phenol, methylene chloride, 2-butanone, and acetone. Two general fate models, i.e., WATER9 and TOXCHEM+V3.0 were used to model the IWTP and quantify the air emissions. Monte Carlo and Bootstrap simulation were used for uncertainty analysis. On average, air emissions from the IWTP were estimated to range from 0.003 lb/d to approximately 16 lb/d with phenol being the highest and benzyl alcohol being the least. However, emissions are associated with large uncertainty. The ratio of the 97.5th percentile to the 2.5th percentile air emissions ranged from 5 to 50 depending on pollutants. This indicates point estimates of air emissions might fail to capture the worst scenarios, leading to inaccurate conclusion when used for health risk assessment. (C) 2009 American Institute of Chemical Engineers Environ Prog, 29: 265-271, 2010

Abstract  Using high-pressure liquid chromatography with ultraviolet-visible diode-array detection, we have analyzed polycyclic aromatic hydrocarbons (PAH) in the dichloromethane extracts of soot deposits from coal-burning stoves in several homes of Henan Province, China--including Linxian County, where esophageal cancer rates are some of the highest in the world. Thirty-two individual polycyclic aromatic compounds, ranging in size from three to eight fused aromatic rings, have been unequivocally identified among the soot extract components--including 20 benzenoid PAH, 6 fluoranthene benzologues, 1 cyclopentafused PAH, 1 indene benzologue, 3 oxygenated PAH, and 1 ring-sulfur-containing aromatic. Most of the identified compounds have been observed before among the products of laboratory coal pyrolysis experiments, but two of the components, the six-ring C24H14 napthol[1,2-b]fluoranthene and the eight-ring C30H16 tribenzo[e,ghi,k]perylene, have never before been documented as products of coal in any system. All of the Henan coal soot extracts are remarkably similar qualitatively in that they contain the same set of identified PAH, but absolute levels of individual species vary by up to 5 orders of magnitude, from sample to sample. The bulk of the identified component mass in all of these soot extracts lies in the five- and six-ring PAH--the largest single class being the family of five-ring C20H12 isomers, to which the samples' most abundant components, benzo[b]fluoranthene and benzo[e]pyrene, belong. The five- and six-ring PAH also account for the majority of the samples' known mutagens. The three strong mutagens identified in these soot samples are the C20H12 benzo[a]-pyrene and two C24H14 PAH, dibenzo[a,e]pyrene and naphtho-[2,1-a]pyrene. Seven moderate mutagens are found among the C20H12, C22H12, C22H14, and C24H14 PAH. A major class of mutagens, the cyclopenta-fused PAH, appears to be absent from these samples, but our detection of an oxidation product of the major mutagen cyclopenta[cd]- pyrene--itself mutagenic--suggests that these soot deposits may contain additional mutagenic cyclopentafused PAH oxidation products as well.

Abstract  Poly(DNTD,N,N'-di[p-phenylamino(phenyl)]-1,4,5,8-naphthalene tetracarboxylic diimide) and its nanocomposite film incorporated with WO3 nanoparticles was prepared by a facile electropolymerization method on an indium in oxide (ITO) coated glass slide from the DNTD monomer and WO3 nanoparticles suspended methylene chloride solution. The morphology and microstructure of the nanocomposite film were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The SEM image shows that the WO3 nanoparticles are uniformly embedded in the polymeric matrix. The nanocomposite film also displays smooth topography with evenly sized and uniformly distributed nanoparticles under high resolution AFM observations. An air-stable electrochromical window was assembled and obtained by a homemade electrochemical cell to study the electrochromism and stability of the nanocomposite film. The composite film exhibits multiple colors at both the cathodic and anodic potentials, i.e., light blue at -1.4 V, orange red at -0.8 V, colorless at 0 V, orange green at 0.8 V, light blue at 1.0 V, and deep blue at 1.2 or 1.4 V vs Ag/AgCl in propylene carbonate containing 1.0 M LiClO4 electrolyte. The UV-visible incorporated electrochemical spectroscopy coupled with amperometry were also employed to study the composite film under different potentials in the range of -1.4 to 1.4 V vs Ag/AgCl. The composite film also shows stable electrochromism even after 100 scans. The thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) analysis suggest the hydrogen bonding formed between the monomers and WO3 particles, resulting in an increased initial oxidation potential for the monomer during the poly(DNTD)/WO3 nanocomposite film formation.