Atmospheric Deposition of Nitrogen and Air Toxins to the

Preparing to load PDF file. please wait...

0 of 0
100%
Atmospheric Deposition of Nitrogen and Air Toxins to the

Transcript Of Atmospheric Deposition of Nitrogen and Air Toxins to the

Atmospheric Deposition of Nitrogen and Air Toxins to the Tampa Bay Estuary
Final Report
September 2002
Prepared for
Tampa Bay Estuary Program Mail Station I-1/NEP 100 8th Avenue S.E. St. Petersburg, Florida 33701
Prepared by
Noreen D. Poor, Ph. D., P. E. University of South Florida College of Public Health 13201 Bruce B. Downs Boulevard Tampa, Florida 33612

Acknowledgements
The research presented in this report represents the combined efforts of national team of managers, scientists and engineers and the financial or “in-kind” support of government and academic institutions. The interpretation of the research reflects the viewpoint of the author and does not represent a position or opinion of any of the participating agencies or individuals unless specifically stated or cited within the report.
Ms. Holly Greening, Tampa Bay Estuary Program; Dr. John Ackermann, USEPA; and Dr. Thomas Atkeson, Florida Department of Environmental Protection (FDEP) were Program Managers for key tasks of this research. FDEP chemists Drs. Liang Lin, Adrian Niculescu, S. Reddy, and Kerry Tate, FDEP, conducted the organics and gravimetric analyses; and University of Michigan Professor Dr. Gerald Keeler supervised the collection of mercury and metals samples by the Environmental Protection Commission of Hillsborough County (EPCHC) and the trace level analyses done in his laboratory. University of Maryland Professor Dr. John Ondov did particle deposition modeling with an updated “Williams” model; University of South Florida (USF) Professor Dr. Bhethanabotla integrated this model with the NOAA buoy model and made the model accessible through the Internet. USEPA scientists Dr. James Baugh and Dr. Teri Conner contributed the XRF metals and scanning electron microscope (SEM) analyses, respectively. Manager Mr. Andrew Weitz, Harding-ESE, Inc., oversaw the laboratory analyses of the annular denuder system samples; and Mr. Robert Cary, President, Sunset Laboratories, handled the organic and elemental carbon analyses. USF Professor Dr. Scott Campbell and USF Assistant Professor Dr. Arlene Laing have had a dual role of faculty supervisor for the student research and in modeling the fate and transport of nitrogen. Drs. Ray Pribble of Janicki Environmental, Inc., and Curtis Pollman, Tetra Tech, Inc., reviewed this research. Chemist Alicia Garcia contributed her talents to the laboratory work at USF.
The EPCHC, under the leadership of first Mr. Roger Stewart and later Dr. Richard Garrity, supported this initiative from its conception and provided support through the Air Management Division and its Directors, first Ivan Chorenenko and later Jerry Campbell. The enthusiasm and expertise of Branch Head Mr. Leroy Shelton, and the Air Monitoring Group managed by Mr. Thomas Tamanini, spearheaded the expansion of the TBADs effort at the Gandy Bridge site.
An integral part of this research was the undergraduate and graduate student involvement. Student participants included Mr. Patrick Shell, MSCE, now with TECO, Inc.; Ms. Renee Weaver, MSCE, now with CRB Geological and Environmental Services, Inc.; Ms. Julie Earls, MSPH, now with Schreuder, Inc.; Mr. Jamal Taylor, MSPH, employed in the Bahamas. Current graduate researchers are Ph.D. students Ms. Kerstin Kenty, Chemical Engineering, Ms. Melissa Evans, Chemistry, and Ms. Connie Mizak, Civil and Environmental Engineering; Masters students Mr. Randy Hannaway, Civil and Environmental Engineering, Mr. Paul Tate, Chemistry, Mr. David Smith, Environmental Science and Policy, Ms. Mubeena Begum, Epidemiology and Biostatistics, Mr. Suresh Gudimetla, Chemical Engineering, and Ms. Heather Hendrix, Mr. Scott Mower, and Ms. Xiaodong Qi, all of Environmental and Occupational Health. Current undergraduate researchers are Dwight Anderson, USF Chemical Engineering and Jimmy Foster, UF Chemical Engineering.
2

Table of Contents
Acknowledgements......................................................................................................................................................2 Table of Contents.........................................................................................................................................................3 List of Figures..............................................................................................................................................................4 List of Tables ...............................................................................................................................................................6 Atmospheric Deposition of Nitrogen and Air Toxins to the Tampa Bay Estuary Final Report...................................7
1. INTRODUCTION ...............................................................................................................................................7 1.1 History of TBADS .........................................................................................................................................8 1.2 From TBADS to BRACE ......................................................................................................................10 1.3 Role of Nitrogen ....................................................................................................................................10 1.4 Role of Air Toxins .................................................................................................................................11
2. NITROGEN.......................................................................................................................................................13 2.1 Wet and Dry Deposition Rates ....................................................................................................................13 2.2 Coarse Particle Nitrogen ..............................................................................................................................16 2.3 Organic Nitrogen .........................................................................................................................................18 2.4 Spatial Gradient of Ammonia Across Urban Tampa ...................................................................................20 2.5 Bi-Directional Ammonia Flux at the Air/Water Interface ...........................................................................25 2.6 Sources of Ambient Air Nitrogen ................................................................................................................25 2.7 Summary......................................................................................................................................................33 2.8 Recommendations........................................................................................................................................33
3. AIR TOXINS.....................................................................................................................................................35 3.1 Polychlorinated Biphenyls (PCBs) ..............................................................................................................35 3.2 Organochlorine Pesticides ...........................................................................................................................36 3.3 Polycyclic Aromatic Hydrocarbons (PAHs) ................................................................................................43 3.4 Metals ..........................................................................................................................................................52 3.5 Summary and Recommendations.................................................................................................................62
4. REFERENCES ..................................................................................................................................................64 APPENDIX A METHODS ...................................................................................................................................74
Nitrogen .............................................................................................................................................................74 Metals ................................................................................................................................................................76 PCBs, PAHs and Organochlorine Pesticides .....................................................................................................78 APPENDIX B TBADS AND BRACE PUBLICATIONS.....................................................................................83 APPENDIX C BRACE OBJECTIVES AND MEASUREMENTS MATRIX ......................................................91
3

List of Figures
Figure 1. Monthly dry deposition of nitrogen to Tampa Bay, August 1996-July 2001. ............................................14 Figure 2. Monthly wet deposition of nitrogen to Tampa Bay, August 1996-July 2001.............................................14 Figure 3. Monthly total deposition of nitrogen to Tampa Bay, August 1996-July 2001............................................15 Figure 4. Average daily concentrations of ambient air ammonia as a function of wind speed. and direction. Ammonia
concentrations were measured with an annular denuder system over a three-year period on a 1-in-6 day schedule; average daily resultant wind speed and direction at Tampa International Airport were obtained from the National Climatic Data Center website (NCDC, 2001). Jimmy Foster, June 2001, prepared the graph. .....16 Figure 5. Size distributions for sodium, chloride and nitrate collected at the eastern end of the Gandy Bridge from October to November 2001. Backwards air mass trajectories computed with the NOAA HYSPLIT model (NOAA, 2001) showed (a) marine, (b) mixed marine and terrestrial, and (c) terrestrial wind origins. .............17 Figure 6. Atmospheric deposition rates of organic amine nitrogen and ammonium nitrogen in bulk deposition samples collected at a bayside site in Tampa, Florida. These rates include days with and without rainfall (Hendrix, et al., 2002)........................................................................................................................................19 Figure 7. Daily dry ammonia/ium fluxes estimated from bulk deposition measurements and from inferential modeling based on ambient air concentrations obtained from the annular denuder system (ADS), October 2001 to November 2001. ............................................................................................................................................20 Figure 8. Two-week averaged ammonia concentration gradient across urban Tampa, October 2001 (Tate, 2002). The numbers indicate inventoried ammonia emission sources, as described in Table 2. Units for the color scale are µg/m3. ................................................................................................................................................................23 Figure 9. USGS aerial photograph of Hooker’s Point, Tampa, showing the deep-water ports and industrial complexes. In the months prior to deployment of the PSD network, preliminary or “scoping” ammonia concentration measurements were made by PSD at 4 sites on Hooker’s Point: (S) adjacent to Howard Curran wastewater treatment plant sludge drying beds; (R) next to the railway conveyance for product transfer; (F, D) close to the docks...............................................................................................................................................24 Figure 10. Plot of ammonium nitrogen in Tampa Bay for January 2002. Graphic is courtesy of the Environmental Protection Commission of Hillsborough County. ..............................................................................................26 Figure 11. Ammonia emissions by source category for Pinellas and Hillsborough County. The inventory was assembled by Connie Mizak, June 2001, with data from CMU (2001), the TRI (2001) and the USEPA (2001); and updated by Scott Mower, February, 2002. ..................................................................................................27 Figure 12. Average daily concentrations of ambient air nitric acid as a function of wind speed and direction. Nitric acid concentrations were measured with an annular denuder system over a three-year period on a 1-in-6 day schedule; average daily resultant wind speed and direction at Tampa International Airport were obtained from the National Climatic Data Center website (NCDC, 2001). Jimmy Foster, June 2001, prepared the graph. .....28 Figure 13. Rainwater concentrations (top) and nitrogen wet deposition rates (bottom) by air mass trajectory for nitrate and ammonia (Smith, et al., 2001). Analyzed were 293 daily rainfall samples collected at the Gandy Bridge site from August 1996 to December 2000. Trajectories were obtained from the NOAA HYSPLIT website (http://gus.arlhq.noaa.gov/ready/hysplit4.html). ...................................................................................32 Figure 14. Daily pesticide concentrations observed on a 1-in-6 day sampling schedule from March-October 2001 at the Gandy Bridge site in Tampa, Florida. ..........................................................................................................38 Figure 15. A comparison of the 1995 (Frithsen et al., 1995) and 2001 direct atmospheric loading of pesticides to the Tampa Bay Estuary............................................................................................................................................39 Figure 16. Correlation of endosulfan (r=0.15) and chlordane (r=-0.58) with average daily wind speed. Wind speed was obtained for the Tampa International Airport from the National Climatic Data Center website. Chlordane and endosulfan concentrations were measured at the Gandy Bridge site in Tampa, Florida, from MarchOctober, 2001. For chlordane, an exponential model fit the data better than a linear model, but neither model fit the endosulfan data. ...........................................................................................................................................41 Figure 17. Clausius-Clapeyron plots for endosulfan (r=-0.02) and chlordane (r=-0.59). Average daily temperatures were obtained for the Tampa International Airport from the National Climatic Data Center website. Chlordane and endosulfan concentrations were measured at the Gandy Bridge site in Tampa, Florida, from MarchOctober, 2001. ...................................................................................................................................................42 Figure 18. Ratio of γ- to α-chlordane. Lower ratios imply more photodegradation of the γ isomer, and thus a longer transport distance. ..............................................................................................................................................42 Figure 19. Total daily rainfall was obtained for the Tampa International Airport from the National Climatic Data
4

Center website. Pesticide concentrations were measured at the Gandy Bridge site in Tampa, Florida, from March-October, 2001.........................................................................................................................................43 Figure 20. Daily total PAH concentrations observed on a 1-in-6 day sampling schedule from March-October, 2001 at the Gandy Bridge site in Tampa, Florida. ..........................................................................................................45 Figure 21. Daily PAH concentrations observed on a 1-in-6 day sampling schedule from March-October 2001 at the Gandy Bridge site in Tampa, Florida.................................................................................................................46 Figure 22. Dependence of ambient air fluoranthene (r = 0.53), fluorene (r = 0.27), pyrene (r = 0.52) and phenanthrene (r = 0.40) concentrations on average daily wind speed. ..............................................................49 Figure 23. Dependence of ambient air fluoranthene (r = 0.33), fluorene (r = 0.51), pyrene (r = 0.23) and phenanthrene (r = 0.49) concentrations on average daily PM2.5 (PMFine) concentration. ................................49 Figure 24. Clausius-Clapeyron plots for fluoranthene and pyrene. Average daily temperatures were obtained for the Tampa International Airport from the National Climatic Data Center website. Fluoranthene and pyrene concentrations were measured at the Gandy Bridge site in Tampa, Florida, from March-October 2001. .........49 Figure 25. Total daily rainfall was obtained for the Tampa International Airport from the National Climatic Data Center website. Ambient air phenanthrene concentrations were measured at the Gandy Bridge site in Tampa, Florida, from March to October 2001. ...............................................................................................................50 Figure 26. Ambient air phenanthrene (r = 0.24) and fluorene (r = 0.4) versus nitrogen dioxide (NO2) concentration for measurements made at the Gandy Bridge site in Tampa, Florida, from March to October 2001.................51 Figure 27. A comparison of the 1995 (Frithsen et al.,1995) and direct atmospheric loading of toxic metals to the Tampa Bay Estuary............................................................................................................................................56 Figure 28. Correlation of aluminum with silicon (r=0.99), iron (r=0.98), potassium (r=0.94) titanium (r=0.99), manganese (r=0.97), and chromium (r=0.58) in ambient air particles 10 µm in diameter or smaller (upper graph); correlation of aluminum with iron (r=0.97), manganese (r=0.96), titanium (r=0.82), and chromium (r=0.86) in rainwater (lower graph). ..................................................................................................................58 Figure 29. Correlation of copper with zinc (r=0.75) and lead (r=0.65) in ambient air particles 10 µm in diameter or smaller (upper graph); correlation of copper with zinc (r=0.80), lead (r=0.83), arsenic (r=0.79), and cadmium (r=0.76) in rainwater (lower graph). ..................................................................................................................59 Figure 30. Correlation of nickel with vanadium (r=0.72) in ambient air particles 10 µm in diameter or smaller (upper graph) and correlation of nickel with vanadium (r=0.87) in rainwater (lower graph). .....................................60
5

List of Tables
Table 1. Annual direct atmospheric nitrogen deposition rates to Tampa Bay for inorganic ammonia/ium plus nitric acid/nitrate. ........................................................................................................................................................13
Table 2. Inventoried ammonia emission sources near Hillsborough Bay (TRI, 2001; CMU 2001). ........................22 Table 3. Statistics for precipitation (rain) δ15NH4+ and δ15NO3- and ambient air (dry) total δ15N observations for
complete datasets and by wet and dry seasons, reported in ‰ (per mil), n = number of samples in each category. Dry season was defined as October through May and wet season as June through September. Sampling was done at the Gandy Bridge monitoring site in Tampa, Florida. ...........................................................................30 Table 4. Statistics for precipitation δ15NH4+ and δ15NO3- and ambient air total δ15N for each trajectory class, reported in ‰ (per mil), n = number of samples in each category. Sampling was done at the Gandy Bridge monitoring site in Tampa, Florida. .......................................................................................................................................31 Table 5. Average daily ambient air PCB concentrations measured at the Gandy Bridge monitoring site from March 2001 to October 2001. The detection limit expressed as an ambient air concentration is based on a 324 m-3 sampling air volume (n=36)...............................................................................................................................36 Table 6. Average daily ambient air pesticide concentrations measured at the Gandy Bridge monitoring site from March 2001 to October 2001 .............................................................................................................................37 Table 7. Estimated total direct atmospheric loading (kg yr-1) of chlordane and endosulfan to the Tampa Bay Estuary. ...........................................................................................................................................................................39 Table 8. Average daily ambient polycyclic aromatic hydrocarbon (PAH) concentrations measured at the Gandy Bridge monitoring site from March to October, 2001........................................................................................44 Table 9. Comparison of average PAH (gas + aerosol) concentrations measured at the Gandy Bridge site in Tampa, Florida, with PAH concentrations at “background” and urban sites. Concentrations are in ng m-3...................45 Table 10. Estimated total direct atmospheric loading (kg yr-1) of PAHs to the Tampa Bay Estuary .........................47 Table 11. Comparisons of net annual gas fluxes for Tampa Bay and Chesapeake Bay monitoring sites (Gustafson and Dickhut, 1997)a ...........................................................................................................................................47 Table 12. Correlations between PAHs.......................................................................................................................48 Table 13. Comparison of direct atmospheric deposition rates of metals to Tampa Bay, to the Gulf of Maine (Pike and Moran, 2001), and to Massachusetts Bay (Golomb, et al., 1997). Units are µg m-2 yr-1....................................57 Table 14. Principal components analysis for metals concentrations in rainwater using SAS PRINCOMP procedure. Positive and negative weights less than 0.25 are shown in a lighter type to de-emphasize their relative importance. ........................................................................................................................................................61 Table 15. Physical and chemical properties of selected organochlorine pesticides and PAHs .................................93
6

Atmospheric Deposition of Nitrogen and Air Toxins to the Tampa Bay Estuary Final Report
Noreen D. Poor, Ph.D., P.E. University of South Florida College of Public Health 13201 Bruce B. Downs Boulevard Tampa, Florida 33617
1. INTRODUCTION
Urbanization has placed a significant nutrient and pollution burden on Tampa Bay and its adjacent waters (TBNEP, 1996). Nutrients and other pollutants enter the Bay from urban and agricultural runoff, direct industrial and municipal discharges to surface waters, and atmospheric deposition. In recent years concerned resource managers, scientists and citizens have cooperated in an extraordinary way to reduce regional atmospheric emissions of nitrogen and air toxins, and to better understand how atmospheric deposition of air pollutants affects the water quality of Tampa Bay.
This report seeks to synthesize the knowledge gained from the measurement and interpretation of environmental variables as they relate to atmospheric deposition, and to provide the technical basis for development of community control strategies to reduce the loading to Tampa Bay of nitrogen and of persistent, bio-accumulative and toxic compounds.
The first section of this chapter reviews the history of Tampa Bay atmospheric deposition estimates and related research through 2001. This section is an excerpt from Poor and Pribble (2002). The second section describes the history of the Bay Regional Atmospheric Chemistry Experiment (BRACE) and its research agenda for the future. The third and fourth sections of this chapter outline the research objectives for nitrogen and air toxins, respectively, and summarize the earlier atmospheric loading rate estimates. The research objectives provide the framework for the results and discussion presented in this report.
The key research results, their implications and the policy recommendations for the management of atmospheric deposition of nitrogen and air toxins to Tampa Bay are presented in Chapters 2 and 3, respectively. Chapter 4 lists the cited references, and Appendix A gives an overview of the experimental methods and data analysis techniques.
This report has as its basis both published and yet-to-be published research. Appendix B contains the citations, abstracts and availability of published research. In Appendix C is a succinct matrix of the BRACE monitoring and modeling activities. The environmental data and the corresponding data dictionaries are available on compact diskette from the Tampa Bay Estuary Program.1 Interpretation of the environmental data will evolve along with our knowledge base and from our local, regional, national and even global perspective.
1 Tampa Bay Estuary Program, Mail Station I-1/NEP, 100 8th Avenue S.E., St. Petersburg, Florida 33701; 727.893.2765; [email protected]
7

1.1 History of TBADS
Initial nitrogen and phosphorus loading estimates to Tampa Bay revealed that atmospheric deposition directly to the bay’s surface contributed about 29% of the total nitrogen load and about 31% of the total phosphorus load to the bay (Zarbock et al., 1994). To further assess the contribution of atmospheric deposition to nutrient loading, the TBEP, Hillsborough, Pinellas, and Manatee Counties, and the Florida Department of Environmental Protection (FDEP) asked that the bay be included as an EPA Great Waters Program. The Tampa Bay Atmospheric Deposition Study (TBADS), after approval by the EPA Great Waters Program, began in the spring of 1995, and resulted in dry and wet nutrient deposition data collection from August 1996 through August 2001.
TBADS and NOAA/Great Waters participants agreed on a monitoring site at the eastern end of the Gandy Bridge. Ambient air and rainfall concentration data collected from this site, in concert with meteorological data collected at a mid-bay site, were analyzed to derive the amount of nitrogen and phosphorus being directly deposited to the bay surface. These data were also utilized to estimate contributions of atmospheric deposition to storm water nutrient loadings to the bay.
The Environmental Protection Commission of Hillsborough County (EPCHC) operated and maintained the Gandy Bridge monitoring site and equipment on behalf of the TBEP for the atmospheric deposition studies; Lee Chapin operated and maintained the mid-bay meteorological station and its sensors.
From the first three years of monitoring at the Gandy Bridge monitoring site, the estimates for the direct atmospheric deposition of nitrogen to Tampa Bay were revised downward from 1000 to 760 metric tons/year, or ~24% of the 1985-1991 total nitrogen loads to the bay. For August 1996 through July 1999 the average dry:wet deposition ratio was 0.78, and ammonia gas or rainfall-dissolved ammonium contributed 58% of the total nitrogen deposition (Poor et al., 2001).
Another part of the effort to ascertain the impacts of atmospheric deposition of nutrients to Tampa Bay was an assessment of bulk deposition to the Tampa Bay watershed at seven sites (Dixon et al., 1996). Samples were analyzed for metals, nitrogen, and phosphorus at all sites over a one-year period, with samples from five of the seven sites analyzed for synthetic organics over a 12-week period. Results of the analyses showed that nitrogen loading to the bay from direct atmospheric loadings is 32% of the total nitrogen load to the bay.
This project was followed by an investigation of the relationship between bulk atmospheric deposition and storm water quality, sponsored by the Florida Department of Transportation (Dixon et al., 1998). The goals of this project were to examine spatial variability in bulk deposition and determine any relationships between bulk atmospheric deposition and storm water loadings. Samples were collected at ten sites within the bay’s watershed. Sample analyses showed that ~1.5 times as much nitrogen was found in storm water than was provided by the bulk atmospheric deposition, indicating that sources other than bulk atmospheric nitrogen contributed to the storm water runoff nitrogen load.
8

Additionally, TBEP funded a study with the goal of estimating the contribution of atmospheric deposition of nitrogen to storm water loading. Utilizing nitrogen concentrations from rainfall events at the Gandy Bridge site and rainfall amounts from the small urban watersheds, a relationship was derived relating nitrogen in storm water to the nitrogen deposited by rainfall events. Results showed that approximately the same amount of nitrogen left the watersheds in storm water runoff as was deposited to the watersheds via rainfall from July-December 1997 (BCI and PBS&J, 1999).
Recommended by the TBADS participants and initiated in1998 was a study funded by the Florida Department of Environmental Protection (FDEP) on the stable nitrogen isotopes in rainfall and ambient air for the purpose of classifying the natural versus anthropogenic sources of atmospherically depositing nitrogen. Florida A&M University directed the research, with the University of Virginia responsible for the laboratory analyses.
Coincident with the stable isotope study was an 18-month TBEP-funded effort by EPCHC to compare the nitrogen bulk deposition measurements with the estimates derived from separate wet deposition only plus inferential (i.e., modeled) dry deposition rates.
In May 1999, the TBEP funded the University of South Florida (USF) College of Public Health (COPH) to provide technical and administrative assistance with the analysis and interpretation of the atmospheric deposition data derived from the Gandy Bridge monitoring site and the mid-bay meteorological station. As part of this assistance, USF COPH analyzed the stable nitrogen isotope and bulk deposition data along with the nitrogen ambient air and rainwater concentrations (Poor, 2002).
At the same time and with additional funds from the USEPA Region IV, the atmospheric deposition measurements were expanded to include ambient air concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides, and both ambient air and rainfall concentrations of metals. Sediments of Tampa Bay most heavily impacted by urban or commercial activities have levels of these contaminants that in some cases pose a significant ecological or human health risk (McConnell, et al., 1996). The earliest loading estimates suggested that for some of these toxins the atmospheric loading should not be ignored (Frithsen, et al., 1995). The air toxin measurements began in March 2000 and continued through October 2001.
A consequence of the discovery of the significant ammonia component to the total atmospheric nitrogen deposition, TBADS participants recommended the deployment of passive sampling devices (PSDs) in urban and industrial Tampa to assess the fugitive ammonia emissions from ammonia and ammonium product transport, storage, processing and manufacturing. The earliest attempts to use the PSDs for measuring the relatively low ambient air concentrations met with limited success, but USF COPH continued the testing and by late 2000 with the endorsement of the TBADS participants, the TBEP funded the study. Also funded by the TBEP were further measurements of ambient air coarse particle nitrate, which is formed by the reaction of nitric acid and sea salt, to estimate the coarse particle nitrate contribution to total nitrogen atmospheric deposition.
9

1.2 From TBADS to BRACE
The Bay Regional Atmospheric Chemistry Experiment (BRACE) research proposes to improve the current nitrogen deposition estimate and source apportionment efforts by expanding the air pollutant monitoring network, by deploying state-of-the-art sensors and monitors, and by analyzing and interpreting meteorological and air pollutant concentration data with the most sophisticated atmospheric chemistry and physics models available. Increased monitoring spatial and temporal resolution is key to understanding the contribution of regional nitrogen emission sources to the total nitrogen deposition. The BRACE is funded by the Florida Department of Environmental Protection (FDEP) and TECO, Inc., trust funds, and by “in-kind” contributions of NOAA, USEPA, and Pinellas County Department of Environmental Management.
The anticipated project length is six years: three years of planning, equipment acquisition, contract negotiations, site identification and preparation, and pilot studies; one month of intensive and one year of baseline monitoring; and three years of receptor modeling and air pollutant transport, dispersion, transformation, and deposition modeling. The purpose of the May 2002 intensive monitoring period was to obtain a sufficient number of high quality observations to initialize and evaluate the air quality models. BRACE research activities began in 1999 and both published (Appendix B) and unpublished results have been incorporated into this report. The BRACE objectives and an overview of the planned measurements are listed in Appendix C.
1.3 Role of Nitrogen
Bricker, et al. (1999) classified Tampa Bay as a highly eutrophic estuary, heavily influenced by anthropogenic activities. Their classification for Tampa Bay was based primarily on the chlorophyll a concentrations, an indicator of algal abundance.
In 1996, the Tampa Bay Estuary Program (TBEP) established a Nitrogen Management Consortium of local governments, regulatory agencies and representatives of agriculture, fertilizer industries, and utility companies. This Consortium approved a plan of action to reduce each year by 17 tons the nitrogen influx to the Bay, an annual reduction that “holds the line” on nitrogen loading to Tampa Bay at ~3,500 metric tons yr-1 (TBNEP, 1996). The TBEP nitrogen management paradigm has been that reducing the total nitrogen load will effectively reduce algal blooms (chlorophyll a), which will improve water clarity and permit the re-establishment of sea grasses in Tampa Bay. This paradigm was based on observed and segment-specific relationships between annual nitrogen loading and chlorophyll a concentrations in Tampa Bay (Pribble, et al., 2001a).
Excessive nitrogen in the form of ammonium, nitrite, nitrate and organic amine compounds stimulates the growth of algae in sunlit and quiescent surface waters (Wang, 1999). These algal mats exude noxious odors, increase water turbidity and reduce sea grass populations, and during decomposition can decrease dissolved oxygen concentrations to levels lethal to fish. The oxidation of reduced nitrogen compounds further depletes dissolved oxygen concentrations.
The TBEP estimated that direct atmospheric deposition of nitrogen to the Bay contributes between 15% and 30% of the total nitrogen loading to Tampa Bay (Pribble, et al., 2001c;
10
NitrogenDepositionTampaTampa BayFlorida