Our understanding about the presence, behavior, and toxicities of atmospheric persistent organic pollutants is limited by our ability to accurately measure them. This dissertation details the development and characterization of a model for the determination of an accurate sampling rate (Rs), and effective sampling volume (Veff), for polyurethane equipped passive air samplers (PUF-PAS), and the subsequent application of PUF-PAS sampling methods towards novel applications studying polychlorinated biphenyls (PCBs). The user friendly mathematical model resulting from this work, published as a Matlab script, predicts Rs and Veff as a function of local hourly meteorology and the physical-chemical properties of the target analytes. The model was first developed using active sampling methods in urban Chicago, where good agreement was found between the PUF-PAS and high volume active samplers: Active/Passive = 1.1 ± 1.2. The model was then expanded and calibrated globally using the dataset from the Global Atmospheric Passive Sampling (GAPS) network. After this global calibration we found acceptable agreement between modelled and depuration-determined sampling rates for an independent dataset, with several compounds having near zero mean percent bias (±6%). The globally applicable model is the best alternative for locations experiencing low average wind speeds or cold temperatures, and is particularly useful for the interpretation of samples with long deployments, deployments conducted under warming conditions, and compounds with high volatility. An interactive web-based graphical user interface for the sampling rate model was developed. Users input sampler locations, deployment dates, and target chemicals, in the web-interface and are provided with a sample and compound specific Rs and Veff. The sampling rate model was examined for use in the indoor environment and it was found that both the experimentally calibrated (1.10 ± 0.23 m3 d-1) and modeled (1.08 ± 0.04 m3 d-1) Rs agreed with literature reports. Correlating sample specific wind speeds with uptake rates, it was determined that variability of wind speeds throughout the room significantly (p-value < 0.001) affected uptake rates. Despite this, the PUF-PAS concentration measurements using modelled Rs values were within 27% of the active sampling determined concentration measurements. Using PUF-PAS samplers, PCBs 47, 51, and 68 were found to account for up to 50% of measured indoor sum PCB concentration (2700 pg m-3). Direct surface measurements were conducted to identify finished cabinetry to be a major source, as a result of the decomposition of 2,4-dichlorobenzoyl peroxide used as an initiator in free-radical polymerization of polyester resins. While this phenomenon has been detected at trace levels in other polymer products, it has never been shown to be a significant environment source of PCBs. PUF-PAS samplers were similarly used to study the presence of airborne hydroxylated polychlorinated biphenyls (OH-PCBs) and PCBs in the metropolitan Chicago area. While OH-PCBs have been hypothesized to be an important removal mechanism for atmospheric PCBs, they were not directly measured in the air until recently. The two most frequently detect OH-PCB congeners in this study, 2OH-PCB2 and 6OH-PCB2, were detected at levels comparable to a previous report of atmospheric OH-PCBs utilizing active sampling methods, suggesting the viability of PUF-PAS methods to study atmospheric OH-PCBs. One sampling site detected as many as 50 OH-PCBs but uncertainties with sampling and laboratory methods prevent any strong conclusions from being drawn.

Indoor air concentrations of volatile organic compounds (VOCs), including many with documented adverse health effects, vary widely but are generally higher than found outdoors. Volatile organic compounds can enter indoor environments via internal (e.g. paints, paint strippers, fuels, cleaning supplies, pesticides, building materials, adhesives) and external sources (e.g. vapor intrusion (VI) from contaminated soil and/or groundwater and ambient air from automobiles and industrial facilities). Since many consumer products contain volatile organic compounds (VOCs) that are also the focus of soil and groundwater cleanup projects, emissions of these VOCs can lead to false source identifications during VI investigations. Laboratory-measured emissions of VOCs from several consumer products were used with a standard box model to predict indoor air concentrations. The predicted concentrations were compared to measured values generated by introducing the same consumer products into an actual residence. The screening level agreement between measured and estimated air concentrations suggests that a standard box model can be used with laboratory measured emission rates to show if an emission source can cause a potential health risk or lead to false assumption during VI investigations. The use of plant leaves as a simple, cost-effective and sustainable approach to sampling indoor air concentrations of VOCs was also investigated in three studies: 1) a headspace approach; 2) a flow-through glass and stainless steel plant growth chamber, and 3) a house-scale study where plant leaf and air concentrations of VOC were simultaneously measured. Similar relationships between the leaf and air concentrations observed in the three studies suggest that plant leaf concentrations can be used as a surrogate for indoor air concentrations of VOCs.

There is currently high demand for new building materials which are considered "environmentally friendly" or "green" for both new construction and renovations. Spray polyurethane foam (SPUF) insulation has gained significant acceptance by both consumers and the construction industry due to its high R-value, which results into significant energy savings among other things. Despite its acceptance by consumers and the construction industry, consideration must be given to potential chemical exposures to applicators installing these products. This study sought to determine, through quantitative experimentation, if there was a release of glycol derivatives including, diethylene glycol (DEG), ethylene glycol (EG), and propylene glycol (PEG), during the application of SPUF. In addition, total volatile organic Compounds (tVOCs) and various environmental parameters were also collected during this research. This study utilized a two-component small-scale SPUF kit manufactured by the Dow Chemical Company, known as the FROTH-PAK™ kit. This specific kit is typically used by the construction industry to fill cavities, cracks, floor and wall penetrations, and expansion joints of buildings. In order to determine the presence of these glycol derivatives, personal breathing zone samples were collected during the application of the SPUF during three application trials. Glycols derivatives were measured using active sampling techniques. Supplementary parameters including tVOCs, ambient and wet-bulb temperature, relative humidity, carbon monoxide, and carbon dioxide, were measured using direct-reading techniques. During this study several modifications were made to the work area and the air sampling methodology to assist in verifying the presence of the glycols and the conditions in which they may be present in the air during the application of SPUF insulation. All samples were sent to an accredited laboratory and were analyzed by the Nation Institute of Occupational Safety and Health Method 5523. During this study, measurable amounts of diethylene glycol and propylene glycol were detected in two of the trials in which no ventilation in the work area was utilized. During one trial in which a work area ventilation system was utilized, none of the glycols were detected in the laboratory analysis above the limit of detection given the analytical method. Ethylene glycol was not detected in any of the samples submitted for analysis. The results for the tVOC measurements were inconclusive. Based on the results of the air sampling, it is likely that exposure to diethylene glycol and propylene glycol may occur under certain conditions. However, due to the limited number of samples and the variation between the samples collected in this study, a generation rate or concentration buildup estimate for comparison of the OELs was not conducted. These conditions include the quantity of ventilation used during application, the application duration, and proper operation of the SPUF application equipment. Based on the results, there is evidence that additional research may be needed in this area.

The aims of the work this thesis is based upon were to develop convenient analytical procedures for determining resin acids in biological and environmental matrices, and apply them to enhance understanding of the occurrence, exposure to and uptake by exposed individuals of resin acids. Particular focus has been on the workplace environment of the Swedish wood pellets industry. Sample extraction procedures and high-performance liquid chromatography/electrospray ionisation-mass spectrometry (HPLC/ESI-MS) methodologies were developed for measuring resin acids in dust, skin and urine samples. Chromatographic separation of abietic (AA) and pimaric acid was achieved by using a polar-embedded C12 stationary phase. The HPLC/ESI-MS method avoids undesirable oxidation of AA, which was found to occur during the derivatisation step in the standard MDHS 83/2 gas chromatography/flame ionisation detection (GC/FID) methodology, leading to false observations of both AA and the oxidation product 7-oxodehydroabietic acid (7-OXO). Personal exposures to resin acids in the Swedish wood pellet production industry were found to be lower, on average, than the British Occupational Exposure Limit for rosin (50 µg/m3). The oxidised resin acid 7-OXO, was detected in both dust and skin samples indicating the presence of allergenic resin acids. A correlation between air and post-shift urinary concentrations of dehydroabietic acid (DHAA), and a trend towards an increase in urinary 7-OXO during work shifts, were also observed. Whether the increase in 7-OXO was due to direct uptake or metabolism of other resin acids cannot be concluded from the results. An efficient HPLC/UV methodology with diode-array detection was developed for screening commercial products for rosin that could be used in laboratories lacking mass spectrometers. Very high concentrations of free resin acids were detected in depilatory wax strips using the method. / At the time of doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Submitted.

This thesis covers sampling and analytical procedures for isocyanates (R-NCO) and amines (R-NH2), two kinds of chemicals frequently used in association with the polymeric material polyurethane (PUR). Exposure to isocyanates may result in respiratory disorders and dermal sensitisation, and they are one of the main causes of occupational asthma. Several of the aromatic diamines associated with PUR production are classified as suspected carcinogens. Hence, the presence of these chemicals in different exposure situations must be monitored. In the context of determining isocyanates in air, the methodologies included derivatisation with the reagent di-n-butylamine (DBA) upon collection and subsequent determination using liquid chromatography (LC) and mass spectrometric detection (MS). A user-friendly solvent-free sampler for collection of airborne isocyanates was developed as an alternative to a more cumbersome impinger-filter sampling technique. The combination of the DBA reagent together with MS detection techniques revealed several new exposure situations for isocyanates, such as isocyanic acid during thermal degradation of PUR and urea-based resins. Further, a method for characterising isocyanates in technical products used in the production of PUR was developed. This enabled determination of isocyanates in air for which pure analytical standards are missing. Tandem MS (MS/MS) determination of isocyanates in air below 10-6 of the threshold limit values was achieved. As for the determination of amines, the analytical methods included derivatisation into pentafluoropropionic amide or ethyl carbamate ester derivatives and subsequent MS analysis. Several amines in biological fluids, as markers of exposure for either the amines themselves or the corresponding isocyanates, were determined by LC-MS/MS at amol level. In aqueous extraction solutions of flexible PUR foam products, toluene diamine and related compounds were found. In conclusion, this thesis demonstrates the usefulness of well characterised analytical procedures and techniques for determination of hazardous compounds. Without reliable and robust methodologies there is a risk that exposure levels will be underestimated or, even worse, that relevant compounds will be completely missed.

It has been estimated that over 200,000 healthcare professionals may be exposed to waste anesthetic gases and are at risk of occupational injury. In 1977, the National Institute for Occupational Safety and Health (NIOSH) issued the publication: Criteria for a Recommended Standard....Occupational Exposure to Waste Anesthetic Gases and Vapors. This publication was based primarily on scientific evidence from human and animal studies suggesting that chronic exposures to anesthetic gases increases the risk of both spontaneous abortion and congenital abnormalities in offspring among female workers and wives of male workers exposed to waste anesthetic gases. In this recommended standard, NIOSH defines the recommended exposure limits (REL) for nitrous oxide and halogenated anesthetics. NIOSH recommended a time-weighted average (TWA) REL of 25 parts per million (ppm) for nitrous oxide over the period of administration. The REL for halogenated anesthetic gases is a ceiling limit of two ppm.In this study, waste anesthetic gas exposures to seven Post Anesthesia Care Unit (PACU) nurses were quantified during one day of air sampling within their breathing zones. Nitrous Oxide was sampled using a ChemExpressTM Personal Monitor (Assay Technology, Inc. Pleasanton, CA) attached to the nurse's lapel for approximately three hours. A total of 15 samples were collected. Isoflurane, desflurane, and sevoflurane were sampled using a ChemExpressTM Personal Monitor (Assay Technology, Inc. Pleasanton, CA) attached to the nurse's lapel for approximately three hours. A total of 15 samples were collected. In addition, Isoflurane, desflurane, and sevoflurane were also sampled using Anasorb© 747 sorbent tubes (SKC, Inc. Eighty Four, PA) to compare the passive and active sampling methods. The tubes were attached to the nurses lapel for one hour. A total of 15 samples were collected. The exposures to nitrous oxide and halogenated anesthetics were below the NIOSH RELs. An Analysis of Variance (ANOVA) showed a statistically significant difference (p < 0.05) in the active and passive sampling methodologies.

published_or_final_version / abstract / toc / Chemistry / Master / Master of Philosophy

No abstract available. / Thesis (Ph.D.)-University of Natal, Durban, 1985.

The presence of complex mixtures of compounds in ambient air, many of which are either unknown or uncharacterised makes an assessment of risk associated with these exposures problematic. Bioanalytical methods can provide an integrative assessment of complex mixture potency for specific mechanisms of toxicity within these contexts. The aim of this study was to evaluate the suitability of monitoring ambient air exposures as sampled by (polyurethane foam) PUF passive air samplers (PAS) using effect based techniques (bioanalytical methods). Passive samplers have the advantage of offering a low-tech inexpensive monitoring strategy which can thereby increase sampling capacity across a broader range of scenarios simultaneously. One challenge posed by the application of passive samplers in particular for these assessments has been the expression of potency estimates in relatively non-comparable terms specific to a given dose of the sampler or for a specific deployment period. The project was therefore designed in order to address these aims and previously identified challenges by investigating the applicability of these techniques for: monitoring in both indoor and outdoor air, the determination of seasonal exposure gradients; the determination of exposure gradients in different locations (urban capitals, regional centres, background); and the application of in-situ calibration to provide comparable effect measurements in terms of equivalent reference compound air concentrations. Air sampled using PUF PAS was monitored for its capacity to induce biological responses which are mechanistically relevant to critical health endpoints in these scenarios. The mechanisms assessed included genotoxicity (DNA damage – umuC assay), Aryl hydrocarbon receptor (AhR) activity (CAFLUX assay), and estrogenicity (ESCREEN assay). The findings from this effect based monitoring revealed that the level of biological response measured changes with the exposure scenario (indoor vs. outdoor; summer vs. winter; urban capital cities vs. background locations). Estrogenicity for example assessed as estradiol equivalent air concentrations (E Eq BIO) averaged 54 pg.m-3 (1.5 - 185 pg.m-3) in indoor air, while samples from ambient air were found to be not estrogenic. Total aryl hydrocarbon receptor (AhR) activity assessed as 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalent air concentrations (TCDD Eq BIO) averaged 4.1 pg.m-3 (1.3 – 7.2 pg.m-3) in indoor air while samples from ambient air averaged 15 pg.m-3 (1.5 – 46 pg.m-3)in summer and 53 pg.m-3 (2.2 – 251 pg.m-3) in winter. The relationship for both direct (-S9) and indirect (+S9) acting genotoxicity and AhR activity were found to be relatively consistent with respect to both season (elevated in winter) and location (elevated in urban capital cities). Overall suitable techniques were developed for combining passive sampling with multiple end-point toxicity testing and it was demonstrated that these techniques may be applied across different exposure scenarios. During the course of this method development and interpretation process a range of limitations were identified relating to: the use and application of effect based techniques to monitor environmental samples; the use of passive samplers within this context specifically; and also with the application of in-situ calibration techniques to passive samplers to improve the comparability of these assessments.

No description available.