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2000 Progress Report: Effect of Photochemical Reactions in Fog Drops and Aerosol Particles on the Fate of Atmospheric Chemicals in the Central Valley
EPA Grant Number: R825433C026Subproject: this is subproject number 026 , established and managed by the Center Director under grant R825433
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: EERC - Center for Ecological Health Research (Cal Davis)
Center Director: Rolston, Dennis E.
Title: Effect of Photochemical Reactions in Fog Drops and Aerosol Particles on the Fate of Atmospheric Chemicals in the Central Valley
Investigators: Anastasio, Cort
Institution: University of California - Davis
EPA Project Officer: Levinson, Barbara
Project Period: October 1, 1996 through September 30, 2000
Project Period Covered by this Report: October 1, 1999 through September 30, 2000
RFA: Exploratory Environmental Research Centers (1992)
Research Category: Center for Ecological Health Research , Targeted Research
Description:
Objective:To determine how photochemical reactions in fog drops and aerosol particles affect the fate and transport of atmospheric pollutants in the Central Valley.
Progress Summary:1. Photochemical reactions in fog waters. We have measured the formation of oxidants (hydroxyl radical and singlet molecular oxygen) and the destruction of organic nitrogen compounds (including amines and heterocyclic nitrogen compounds) in Davis fog waters illuminated with simulated sunlight. The oxidant measurements were made in order to be able to predict the lifetimes of pollutants in fog drops and aqueous aerosol particles. The reactions of organic nitrogen (ON) compounds were examined because there are significant amounts of ON in the troposphere, it represents a significant fraction of the total nitrogen deposited to Lake Tahoe (and, undoubtedly, most of the Sierra-Nevada range), and because extremely little is known of its atmospheric chemistry.
Our photochemical experiments have demonstrated that several organic nitrogen species are rapidly destroyed in sunlight-illuminated fog drops, while a number of other ON species are relatively unaffected. These results are significant for a number of reasons. First, they suggest that atmospheric reactions of organic nitrogen may increase its bioavailability and therefore its biological impact after deposition. Second, the fact that a number of amino acids and alkyl amines were not appreciably destroyed during illumination indicates that these compounds may be useful tracers for organic nitrogen deposited in the Sierras. Third, these photodestruction reactions suggest that the oxidation of organic nitrogen may be a source of inorganic nitrogen (e.g., nitrate and ammonium) in the atmosphere.
Our oxidant results showed surprisingly low concentrations of hydroxyl radical, indicating that it is not a significant sink for the destruction of reactive compounds. This is significant because it suggests that current models of fog water chemistry are likely overestimating the importance of OH as a sink for organic pollutants. Second, the concentrations of 1O2* indicate that it can be an important sink for a number of compounds, including some organic nitrogen compounds, polycyclic aromatic hydrocarbons (PAH) and phenols. Results from these studies are currently in press in Atmospheric Environment.
2. Speciation and quantification of atmospheric nitrogen. Because atmospheric deposition has likely been an important source of nitrogen to the Sierras (as seen for Lake Tahoe) we have been working to identify and quantify the atmospheric nitrogen compounds over the Central Valley and Sierras. As one component of this work we have collected biweekly aerosol samples in Davis for the past year. We have analyzed these samples for ammonia, nitrate, nitrite and amino acids and are currently working to determine concentrations of total organic nitrogen. Our data indicate that ammonia concentrations are strongly correlated with (and much higher than) concentrations of amino acids and that both concentrations are highest in the spring. Furthermore, we have found that the amino acids which were most quickly destroyed in our photochemical experiments described above were not found in any of the aerosol samples.
In addition to this ground-based sampling of particles, in conjunction with John Carroll and Alan Dixon we recently started to collect nitrogenous gases and particles from aircraft flights over the Sacramento area and Sierra foothills. Our hope with these flights is to be able to characterize the emission and transport of nitrogen over the Central Valley and Sierras. Although preliminary, our initial results indicate that there are significant concentrations of both particulate organic nitrogen (including amino acids) and gaseous inorganic nitrogen (primarily ammonia) in these regions.
In addition, we are currently preparing to do flights inside and just outside of the Lake Tahoe air basin. The goal of these flights is to examine whether we can qualitatively understand the importance of out-of-basin transport of pollutants, including nitrogen species and ozone, to the Tahoe airshed.
3. Generation, transport, and fate of pesticides sorbed to soil dust. Evidence from a few previous studies indicates that pesticides bound to airborne soil particles can be transported long distances, suggesting that these dust-bound residues might have significant effects upon air quality, human health, and ecosystem health. Despite this, little is known about the flux of dust-bound pesticides from agricultural operations. Similarly, very little is known about the atmospheric reactions of pesticides sorbed to airborne soil particles, or how sorption affects the lifetimes of these residues.
In conjunction with Britt Holmén (Crocker Nuclear Laboratory) and Tom Young (Civil and Environmental Engineering), we have started a study to quantify the fluxes of gaseous and particle-bound pesticides from agricultural fields during application and soil-incorporation of two pre-emergence herbicides. In addition, we are beginning laboratory experiments to characterize the atmospheric lifetimes of pesticides in the gas phase and bound to soil dust. Based on these data, we hope to be able to evaluate the importance of soil-derived aerosol particles as a means for the long-range transport of pesticides (e.g., from the Central Valley to the Sierra-Nevadas).
Supplemental Keywords:Ecosystem Protection/Environmental Exposure & Risk, INTERNATIONAL COOPERATION, Geographic Area, Scientific Discipline, Waste, RFA, Air Quality, Analytical Chemistry, Ecological Risk Assessment, Atmospheric Sciences, Fate & Transport, Environmental Chemistry, Forestry, Monitoring/Modeling, Ecology and Ecosystems, Environmental Monitoring, State, biomarkers, California (CA), fate and transport, fog water chemistry, bioaccumulation, ecological risk, field detection, soil dust, atmospheric deposition, emissions, monitoring, PCBs, analytical models, detection system, fish consumption, Lake Tahoe, emission control, air pollution, atmospheric chemistry, environmental measurement, pesticides, modeling, watershed influences, kinetics, food chain
Progress and Final Reports:
1999 Progress Report
Original Abstract
Final Report
Main Center Abstract and Reports:
R825433 EERC - Center for Ecological Health Research (Cal Davis)
Subprojects under this Center:
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R825433C001 Potential for Long-Term Degradation of Wetland Water Quality Due to Natural Discharge of Polluted Groundwater
R825433C002 Sacramento River Watershed
R825433C003 Endocrine Disruption in Fish and Birds
R825433C004 Biomarkers of Exposure and Deleterious Effect: A Laboratory and Field Investigation
R825433C005 Fish Developmental Toxicity/Recruitment
R825433C006 Resolving Multiple Stressors by Biochemical Indicator Patterns and their Linkages to Adverse Effects on Benthic Invertebrate Patterns
R825433C007 Environmental Chemistry of Bioavailability in Sediments and Water Column
R825433C008 Reproduction of Birds and mammals in a terrestrial-aquatic interface
R825433C009 Modeling Ecosystems Under Combined Stress
R825433C010 Mercury Uptake by Fish
R825433C011 Clear Lake Watershed
R825433C012 The Role of Fishes as Transporters of Mercury
R825433C013 Wetlands Restoration
R825433C014 Wildlife Bioaccumulation and Effects
R825433C015 Microbiology of Mercury Methylation in Sediments
R825433C016 Hg and Fe Biogeochemistry
R825433C017 Water Motions and Material Transport
R825433C018 Economic Impacts of Multiple Stresses
R825433C019 The History of Anthropogenic Effects
R825433C020 Wetland Restoration
R825433C021 Sierra Nevada Watershed Project
R825433C022 Regional Transport of Air Pollutants and Exposure of Sierra Nevada Forests to Ozone
R825433C023 Biomarkers of Ozone Damage to Sierra Nevada Vegetation
R825433C024 Effects of Air Pollution on Water Quality: Emission of MTBE and Other Pollutants From Motorized Watercraft
R825433C025 Regional Movement of Toxics
R825433C026 Effect of Photochemical Reactions in Fog Drops and Aerosol Particles on the Fate of Atmospheric Chemicals in the Central Valley
R825433C027 Source Load Modeling for Sediment in Mountainous Watersheds
R825433C028 Stress of Increased Sediment Loading on Lake and Stream Function
R825433C029 Watershed Response to Natural and Anthropogenic Stress: Lake Tahoe Nutrient Budget
R825433C030 Mercury Distribution and Cycling in Sierra Nevada Waterbodies
R825433C031 Pre-contact Forest Structure
R825433C032 Identification and distribution of pest complexes in relation to late seral/old growth forest structure in the Lake Tahoe watershed
R825433C033 Subalpine Marsh Plant Communities as Early Indicators of Ecosystem Stress
R825433C034 Regional Hydrogeology and Contaminant Transport in a Sierra Nevada Ecosystem
R825433C035 Border Rivers Watershed
R825433C036 Toxicity Studies
R825433C037 Watershed Assessment
R825433C038 Microbiological Processes in Sediments
R825433C039 Analytical and Biomarkers Core
R825433C040 Organic Analysis
R825433C041 Inorganic Analysis
R825433C042 Immunoassay and Serum Markers
R825433C043 Sensitive Biomarkers to Detect Biochemical Changes Indicating Multiple Stresses Including Chemically Induced Stresses
R825433C044 Molecular, Cellular and Animal Biomarkers of Exposure and Effect
R825433C045 Microbial Community Assays
R825433C046 Cumulative and Integrative Biochemical Indicators
R825433C047 Mercury and Iron Biogeochemistry
R825433C048 Transport and Fate Core
R825433C049 Role of Hydrogeologic Processes in Alpine Ecosystem Health
R825433C050 Regional Hydrologic Modeling With Emphasis on Watershed-Scale Environmental Stresses
R825433C051 Development of Pollutant Fate and Transport Models for Use in Terrestrial Ecosystem Exposure Assessment
R825433C052 Pesticide Transport in Subsurface and Surface Water Systems
R825433C053 Currents in Clear Lake
R825433C054 Data Integration and Decision Support Core
R825433C055 Spatial Patterns and Biodiversity
R825433C056 Modeling Transport in Aquatic Systems
R825433C057 Spatial and Temporal Trends in Water Quality
R825433C058 Time Series Analysis and Modeling Ecological Risk
R825433C059 WWW/Outreach
R825433C060 Economic Effects of Multiple Stresses
R825433C061 Effects of Nutrients on Algal Growth
R825433C062 Nutrient Loading
R825433C063 Subalpine Wetlands as Early Indicators of Ecosystem Stress
R825433C064 Chlorinated Hydrocarbons
R825433C065 Sierra Ozone Studies
R825433C066 Assessment of Multiple Stresses on Soil Microbial Communities
R825433C067 Terrestrial - Agriculture
R825433C069 Molecular Epidemiology Core
R825433C070 Serum Markers of Environmental Stress
R825433C071 Development of Sensitive Biomarkers Based on Chemically Induced Changes in Expressions of Oncogenes
R825433C072 Molecular Monitoring of Microbial Populations
R825433C073 Aquatic - Rivers and Estuaries
R825433C074 Border Rivers - Toxicity Studies