1,720,984 research outputs found
Approaches to understanding the cumulative effects of stressors on marine mammals.
No full textIn 2017, The National Academy of Sciences reported on the approaches to understanding the cumulative effects of stressors on marine mammals and suggested the use of baleen whale earplugs to evaluate both stress and stressors. The objective of this dissertation is to investigate historic and current organic and inorganic contaminants within the marine ecosystem to better understand the cumulative effects of stressors on marine mammals. Simultaneously, this dissertation also demonstrate links between. The long-term health impact of organic contaminants was assessed in harbor porpoises off the coast of Washington State. This study focused on the POP burden within the blubber of three females (two adults and one juvenile), one of which had a Bcell lymphoma. POP blubber concentrations from different life stages were used to assess the lifetime POPs burden. The juvenile porpoise had the highest contaminant burden followed by the adult female with lymphoma and the nonlymphoma adult. POP life history exposure profiles were reconstructed using baleen whale earplugs. This earplug study expands upon previous earplug studies of both spatial and temporal trends. POPs analysis using earplugs provided contaminant data 30 years prior to the first reports in marine species. Chemical exposure profiles and bioaccumulation rates were reconstructed for a total of six earplugs from the North Pacific and Atlantic Ocean basins. Bioaccumulation rates were found to be 56 times higher in the North Pacific compared to the North Atlantic, suggesting a higher risk of exposure in the North Pacific. Lastly, a single earplug was used to investigate temporal profiles of inorganic elements. The final study used a single fin whale earplug to produce more than 1,600 data points, which were used to reconstruct 48 distinct profiles of toxic, essential, nonessential, rare earth, and other non-biologically relevant elements. This research, in conjunction with concurrent studies, aimed to examine stress profiles and other stressors (e.g., reproduction and whaling; see appendix). Earplug data from this study provides insight into biological and biogeochemical processes as well as preliminary data for further elemental analysis of more earplugs
Atmospheric concentrations of organophosphate esters in Delhi, India.
No full textThe rise of organophosphate esters (OPEs) as ubiquitous global air pollutants is in part associated with their high-production volume, physical and chemical properties, and heavy use in consumer products, including many electronics. The current study investigates the composition and seasonal variability of atmospheric OPEs in Delhi, India. Atmospheric PM2.5 (particulate matter with an aerodynamic diameter ≤ 2.5 microns) samples were collected from April to November 2009 in downtown Delhi. PM2.5 samples were extracted using pressurized liquid extraction and the extracts were analyzed for twelve OPEs, including TPhP, using gas chromatography-mass spectrometry. The sum of atmospheric OPE concentrations ranged from 2.71 to 61.4 ng m^-3 abd were up ~600 times that of concentrations reported in the US. Findings from a study were similar to those reported from e-waste recycling areas in Pakistan, where TPhP was the dominant OPE. This may suggest that e-waste recycling is a major source of atmospheric OPEs in Delhi
Development of network-scale intercomparison techniques and sampling platforms for the black and brown carbon (BC2) aerosol optical network.
No full textCharacterization of aerosols as drivers of climate and air quality through ground-based measurements is exceedingly important, and filter-based absorption photometers are a widely accepted means of deriving the composition and concentration of absorbing aerosols. This study presents data from a collocation of 15 Tricolor Absorption Photometers (TAPs) from the BC2 monitoring network to validate comparability between instruments, while also providing practical considerations for field usage and detailing the development of the sampling infrastructure used for operation. TAPs were correlated via orthogonal regression with a modified goodness-of-fit measure, R2g. Analysis showed distinct "α" and "β" groups offset by a ~50% difference in sensitivity while conserving linearity (R2g = 0.90 - 1.00 in >90% of regressions), revealing a systemic manufacturing defect. Intercomparisons at multiple flow rates and transmittance ranges were consistent with previous studies. Data collected within this study highlights the need for further large-scale, single-instrument intercomparison studies across multiple production periods
Atmospheric concentrations of organophosphate esters in Delhi, India.
No full textThe rise of organophosphate esters (OPEs) as ubiquitous global air pollutants is in part associated with their high-production volume, physical and chemical properties, and heavy use in consumer products, including many electronics. The current study investigates the composition and seasonal variability of atmospheric OPEs in Delhi, India. Atmospheric PM2.5 (particulate matter with an aerodynamic diameter ≤ 2.5 microns) samples were collected from April to November 2009 in downtown Delhi. PM2.5 samples were extracted using pressurized liquid extraction and the extracts were analyzed for twelve OPEs, including TPhP, using gas chromatography-mass spectrometry. The sum of atmospheric OPE concentrations ranged from 2.71 to 61.4 ng m^-3 abd were up ~600 times that of concentrations reported in the US. Findings from a study were similar to those reported from e-waste recycling areas in Pakistan, where TPhP was the dominant OPE. This may suggest that e-waste recycling is a major source of atmospheric OPEs in Delhi
Fate and transport of emerging contaminants across a dynamic urban landscape.
No full textTwo major classes of emerging contaminants (flame retardants/plasticizers and current-use pesticides (CUPs)) were measured across Houston, TX. Atmospheric particulate matter (PM) samples were taken at high spatial resolution in conjunction with NASA’s DISCOVER-AQ Houston campaign, a month-long, sampling intensive campaign in September 2013. Samples were taken at four ground-based sampling sites (300 filter-based PM samples) at least daily, improving temporal resolution, in both PM₂.₅ (PM less than 2.5 μm in aerodynamic diameter) and TSP (total suspended particulate) sample size fractions. Select samples collected during this campaign were analyzed for organophosphate esters (OPEs; emerging flame retardants/plasticizers) and CUPs (including mosquito adulticides). To analyze samples for these and other compounds of interest, a method first had to be developed for the simultaneous extraction of over 130 organic tracers (e.g., current- and historic-use pesticides, PCBs, OPEs, PBDEs, PAHs, alkanes, hopanes, and steranes). The extraction is carried out using pressurized liquid extraction, an automated technique, with extracts capable of being analyzed on multiple instruments to expand analysis capabilities. OPEs and CUPs (including mosquito adulticides) were examined for spatial and temporal heterogeneity, with large variability observed among urban, suburban, and industrial sampling sites, as well as day-to-day and diurnal differences. OPEs were also compared to bulk carbon measurements to improve understanding of atmospheric transport across the four sites. For mosquito adulticides, the oxidation of malathion was of particular interest. This oxidation not only appears to proceed faster than previous estimates from agricultural-based studies (hours compared to days), oxidation appears to occur during the night, due to reaction with either ozone or nitrate radicals. Determinations of atmospheric PM concentrations of emerging contaminants, specifically flame retardants and CUPs, lies at the interface of environmental and human health, as both classes of compounds have known benefits to humans, but also known toxicities. Additionally, spatial and temporal heterogeneity of these emerging contaminants in an urban area suggest that long-term sampling schemes (24 h samples taken on a 1-in-6 or 1-in-12 day sampling schedule) may not be representative of the day-to-day atmospheric PM concentrations present in these dynamic urban landscapes
High-throughput analysis of emerging and historical pollutants in biological matrices.
No full textThe Deepwater Horizon Gulf Spill highlighted key deficiencies associated with our ability to analyze contaminants in biological tissue in a timely manner. These deficiencies in laboratory capacity and preparedness demonstrated a critical need to develop and validate high-throughput analytical methods capable of rapid and accurate quantification of organic pollutants in biological tissue from aquatic environments. High-throughput methods offer distinct advantages over historical methods, namely a reduction in the intrinsic costs associated with the sample preparation: time, solvents, labor, laboratory space, training, and potential loss of analytes. Sample preparation steps for the analysis of organic pollutants represent ~2/3 of the analytical cost, and are often the logistical bottleneck for laboratory capacity and preparedness. An enhanced pressurized liquid extraction (ePLE) method was developed for simultaneous analysis of pharmaceuticals and personal care products (PPCPs) in fish tissue and was utilized in a nationwide PPCP study conducted in Germany. The developed high-throughput method incorporated silica gel cleanup with PLE and improved the method sensitivity by optimizing resonant collision induced dissociation energy through ion-trap mass analyzer. The nationwide PPCP study found that the proximity of sampling locations to the upstream wastewater treatment plant discharging point and mean annual flow at the sampling locations were found to significantly powerful predictor of galaxolide and tonalide fish tissue concentrations (galaxolide: r2 = 0.79, p = 0.021 and tonalide: r2 = 0.81, p = 0.037) in Germany. Galaxolide and tonalide, both polycyclic musk fragrance materials, in German fish tissues were ~19 and ~28× lower, respectively, as compared to similar nationwide PPCP study in the United States. Similarly, a high-throughput ePLE method was developed for polychlorodibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like polychlorobiphenyls (dl-PCBs) by incorporating pressurized liquid extraction and multiple cleanup techniques. Sample preparation time and solvents were reduced as much as 95% and 65%, respectively, as compared to a conventional USEPA Method 1613. ePLE extracts were sufficiently clean for high resolution mass spectrometry analysis of PCDD/Fs and dl-PCBs in fish tissues from San Jacinto River Waste Pits, a Superfund site in Houston, TX
Tracking aerosolized mosquito control pesticides in an urban atmosphere.
No full textPublic health authorities release aerosolized pesticides, "adulticides," directly into the atmosphere to control adult mosquito populations and reduce the threat of diseases. Malathion and permethrin, both known neurotoxins, are the primary adulticides used for mosquito control in urban areas. Malathion and permethrin can undergo chemical degradation via atmospheric oxidants, which are present throughout typical urban atmospheres, especially during peak mosquito season (summer). Despite this, adulticides are routinely used in urban areas without fully understanding how atmospheric processes (oxidation) impact their environmental fate. Chamber-based studies have assessed the oxidation of adulticides for select oxidants. However, few studies have assessed the environmental fate and transport of adulticides within the context of urban-scale (multi- county) mosquito control. Described herein is a study specially designed to investigate the spatial and temporal variation, and aerosol size fraction distribution of adulticide transport and oxidation post-application throughout greater Houston across 3 summers. In 2013, atmospheric concentrations of malathion and permethrin at application sites closely reflected the alternating adulticide treatment schedule. Malaoxon, an oxidation product of malathion, was also frequently detected, indicating significant oxidation. The atmospheric half-life of malathion in Houston was estimated at <12 h, which was significantly shorter than previous estimates. These results raise concerns of health effects and adulticide efficacy since malaoxon is potentially less effective as an adulticide and more toxic to humans. In 2016, malathion, malaoxon, and permethrin were measured throughout the sampling campaign at a downwind site, despite the alternating adulticide treatment schedule. Confirmation from NOAA HYSPLIT backward trajectories indicates the downwind site is influenced by multiple county-level mosquito control programs. This cross-county contamination may impact adulticide effectiveness through development of pesticide resistance in mosquito populations, and highlights the need for collaboration between county-level mosquito control programs. In 2017, aggressive efforts to control mosquito population growth post-Harvey presented a unique opportunity to investigate adulticide oxidation with improved temporal resolution. Preliminary analysis highlights the potential for rapid adulticide oxidation (<2 h half-life) during high ozone events in an urban area. This research can be expanded by measuring adulticide oxidation in the gas phase, and observing the impacts of adulticide oxidation on mosquito control efficacy
Fate and transport of emerging contaminants across a dynamic urban landscape.
No full textTwo major classes of emerging contaminants (flame retardants/plasticizers and current-use pesticides (CUPs)) were measured across Houston, TX. Atmospheric particulate matter (PM) samples were taken at high spatial resolution in conjunction with NASA's DISCOVER-AQ Houston campaign, a month-long, sampling intensive campaign in September 2013. Samples were taken at four ground-based sampling sites (300 filter-based PM samples) at least daily, improving temporal resolution, in both PM₂.₅ (PM less than 2.5 μm in aerodynamic diameter) and TSP (total suspended particulate) sample size fractions. Select samples collected during this campaign were analyzed for organophosphate esters (OPEs; emerging flame retardants/plasticizers) and CUPs (including mosquito adulticides). To analyze samples for these and other compounds of interest, a method first had to be developed for the simultaneous extraction of over 130 organic tracers (e.g., current- and historic-use pesticides, PCBs, OPEs, PBDEs, PAHs, alkanes, hopanes, and steranes). The extraction is carried out using pressurized liquid extraction, an automated technique, with extracts capable of being analyzed on multiple instruments to expand analysis capabilities. OPEs and CUPs (including mosquito adulticides) were examined for spatial and temporal heterogeneity, with large variability observed among urban, suburban, and industrial sampling sites, as well as day-to-day and diurnal differences. OPEs were also compared to bulk carbon measurements to improve understanding of atmospheric transport across the four sites. For mosquito adulticides, the oxidation of malathion was of particular interest. This oxidation not only appears to proceed faster than previous estimates from agricultural-based studies (hours compared to days), oxidation appears to occur during the night, due to reaction with either ozone or nitrate radicals. Determinations of atmospheric PM concentrations of emerging contaminants, specifically flame retardants and CUPs, lies at the interface of environmental and human health, as both classes of compounds have known benefits to humans, but also known toxicities. Additionally, spatial and temporal heterogeneity of these emerging contaminants in an urban area suggest that long-term sampling schemes (24 h samples taken on a 1-in-6 or 1-in-12 day sampling schedule) may not be representative of the day-to-day atmospheric PM concentrations present in these dynamic urban landscapes
Investigating volatile organic compound composition in Houston, Texas amidst an atmospheric regime shift.
No full textThe World Health Organization links ~ 7 million premature deaths per year to poor air quality, underscoring the importance of understanding air pollution sources. Urban areas, with dense populations and diverse activities, significantly impact air quality and, consequently, public health. Volatile organic compounds (VOCs) are a key component of urban air quality, emitted from anthropogenic and biogenic sources. Over decades, researchers have characterized VOC emission sources to better understand their role in forming ozone and secondary organic aerosol (SOA). Historically, VOCs from fossil fuel combustion, especially transportation, have been considered major contributors to ozone and SOA formation. However, the decline in automotive VOCs in recent years due to stricter tailpipe regulations has caused other petrochemical VOC sources to grow in relative importance to urban emission inventories. These non-combustion sources, known as volatile chemical products (VCPs), include organic solvent-based personal care products, cleaning agents, and industrial inks and adhesives. These changes in emission inventories highlight a substantial shift from historical VOC source profiles and represents a new challenge in identifying the VOC emission sources leading to sustained air pollution. Houston, Texas, a hub for national petrochemical processing, offers a unique region to study VCPs. Supporting the Houston-based Dept. of Energy-led Tracking Aerosol Convection ExpeRiment (TRACER) project, VOCs were collected on aerial and ground-based platforms to investigate VCPs in the region. In TRACER-Tethersonde (August 2022), a modular VOC sampler was fabricated for flights on two uncrewed aerial platforms, the ARM tethered balloon system and a drone (Chapter Two). The sampler collected VOCs via sorbent tubes, helping to address knowledge gaps in the vertical distribution of VCPs. In September 2021 and 2022 (i.e., TRACER-Air Quality 1 and 2), ground-based VOC measurements were collected at the San Jacinto Battleground State Historic Site, located along the Houston Shipping Channel (Chapter Three). Using proton transfer reaction mass spectrometry, these measurements focused on three known VCP components, capturing temporal variability and evaluating potential VOC sources. This dissertation assesses the VCP variability, highlighting the importance of further characterization as the urban airshed continues to evolve in response to a changing climate and shifts in human activities
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