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Doctorate Dissertation
- 1. Dissertation Melanie McHenry September 2010 Expected Graduation Date: December 2010 Environmental Science Department, School of Science and Technology, College of Science Engineering and Technology, Jackson State University, P.O. Box 18540, 1400 Lynch Street, Jackson, MS 39217 Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve: Profiling Mercury Distribution in the NERR by Cold Vapor Atomic Absorption Spectrometery
- 3. Organic Mercury Most toxic because they are lipophilic & can penetrate the blood brain barrier (BBB), invade the nervous system Inorganic Mercury Ingestion is usually inadvertent or with suicidal intent & gastrointestinal ulceration or perforation & hemorrhage have been rapidly produced it will followed by circulatory collapse Elemental Mercury Volatile at room temperature After inhalation, pass through pulmonary, enter blood and distribute to red blood cells, central nervous system (CNS), & kidneys
- 18. Materials & Methods: The Collection
- 21. Materials & Methods: Sample Analysis
- 26. Materials & Methods: Data Analysis
- 28. Results
- 61. Any Questions
- 62. Total Release Inventory (TRI) On-Site Disposal to Class I Underground Injection Wells, RCRA Subtitle C Landfills, and Other Landfills Other On-site Disposal or Other Releases Chemical Other Onsite Landfills Subtotal Point Source Air Emissions Surface Water Discharges Subtotal Total Onsite Disposal or Other Releases Total Onsite and Offsite Disposal or Other Releases Mercury (lb) Mercury Compounds (lb) 9 9 240 3 243 251 251 CHEVRON PRODUCTS CO PASCAGOULA REFINERY. 250 INDUSTRIAL RD, PASCAGOULA, Mississippi 39581 (JACKSON) Mercury Compounds (lb) 0 0 16 3 18 18 18 MISSISSIPPI POWER CO - PLANT DANIEL. 13001 HWY 63 N, ESCATAWPA, Mississippi 39552 (JACKSON) Mercury Compounds (lb) 9 9 225 0 225 253 253 MIDSTREAM FUEL SVC LLC (PASCAGOULA). 5320 INGALLS AVE, PASCAGOULA, Mississippi 39581 (JACKSON) Mercury Compounds (lb) 0 0 0 0 0 0 0
Notes de l'éditeur
- Good morning everyone. My name is Melanie McHenry and today I’m defending my dissertation entitled Ecotoxicty and Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve: Profiling Mercury Distribution in the NERR by Cold Vapor Atomic Absorption Spectrometry Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- The Element Mercury: Mercury is present in the environment in different forms that have biogeochemical transformation and ecotoxicity. Mercury is one of the most hazardous pollutants in the marine environment. All forms can have adverse health effects at sufficiently high doses. Organic mercury compounds are of particular concern because of their enhanced toxicity, lipophilicity, and bioaccumulation in tissues Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Elemental Mercury is volatile at room temperature. After inhalation, it will pass through pulmonary, enter blood, and distribute to the red blood cells, central nervous system, and kidneys Ingestion of Inorganic Mercury is usually inadvertent or with suicidal intention. Gastrointestinal ulceration or perforation and hemorrhage have been rapidly produced and will be followed by circulatory collapse Organic mercury is the most toxic form of mercury because they are lipophilic and can penetrate the blood brain barrier and invade the nervous system Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- The Mercury Cycle Aquatic systems are a reservoir of mercury containing annual flux to and from the atmosphere Estuaries & coastal waters represent a link between the terrestrial environment & the open waters Small fraction of the mercury transported in rivers is exported to open waters due to the high retention of this metal in estuaries & coastal waters Mercury emissions disperse widely in the atmosphere before being deposited to the earth’s surface The lifetime of mercury in sediments is so long that they can be considered as sinks for this metal Microorganisms in sediments can convert several mercury compounds into a more toxic & water-soluble form Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- The Grand Bay National Estuarine Research Reserve The Grand Bay NERR is about 18,500 acres and the Grand Bay National Wildlife Refuge is 7,000 acres The GBNERR is a vast area of undeveloped coastline and marshes. It consists of a maze of bayous, small bays, marsh islands, and mudflats. There are anthropogenic-induced stressors which are due to the population increase in areas close to the GBNERR. This increase has resulted in substantial land development, dredging, spoil placement, and dumping of wastes This has resulted in considerable habitat loss, increased chemical pollution, and intensified hypoxic events The core area (yellow) consists of approximately 12, 800 acres of estuarine tidal marsh, tidal creeks or bayous, shallow, open-water habitats, oyster reefs, seagrass beds, maritime forests, salt flats, sandy beaches & shell middens The buffer area (blue) consists of approximately 5,600 acres of tidal marsh, scrub shrub, pine flatwood & wet pine savanna habitats Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Mercury in Surface Water: In the year 1970, sampling from lakes and rivers located in the United States demonstrated that about 19% of the waterways were contaminated with mercury with a median value less than 0.5 ppb The main sources of methylmercury in surface water are direct precipitation, watershed runoff, especially from wetlands, and in-lake methylation of inorganic mercury Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Mercury in Sediment The main reservoirs of mercury are the bottom sediments. These are a sensitive indicator of the aquatic ecosystems pollution. The toxicity, bioaccumulation, and mobility will depend on the species and chemical form Concentration/Bioaccumulation Mercury accumulates in bottom sediment via sedimentation The concentration of mercury is an indicator of water pollution Methylation/Microbes Inorganic mercury is transformed into methylmercury in sediments The main factors of sedimentation are microorganisms, inorganic sulfides, iron and manganese hydroxides, redox potential, chlorides and temperature in the bottom sediments Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Yellowfin Mojarra, Pinfish, Sheepshead minnow, Bull minnow, Gulf pipefish, Flounder, Sailfin molly, & Gulf killifish Predatory ocean fish, such as tuna, swordfish, & shark Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- After 1850, the atmospheric emissions increased with increased use in gold mining & coal combustion From 1977 to 1980, mercury increased by 1.2 to 1.5% per year from 1977 to 1990 Since 1990, there has been a decreasing trend in atmospheric mercury concentrations Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Agency for Toxic Substances & Disease Registry (ATSDR): 0.3µg/kg/day Food & Drug Administration (FDA): maximum level of 1 ppm Food & Agriculture Organization of the World Health Organization (FAO/WHO): 3.3µg/kg/week or 200µg/week for adults & infants Health Canada: 0.2µg/kg/day Occupational Safety & Health Administration (OSHA): limits of 0.1 mg/m 3 for MeHg; limits of 0.05 mg/m 3 of metallic mercury vapor for 8-hour shifts & 40-hour work weeks Due to the possible teratogenic effects of mercury to humans Based on neurologic developmental effects Measured in children associated with exposure in utero to MeHg from maternal diet Reference Dose per day 0.1 ug/kg/day For a 70 kg man, the reference dose is 0.001 0.1 ppb for methylmercury 2 ppb for drinking EPA’s RfD for a month 3.0 ppb (30 days) August’s organic mercury level exceeds the EPA’s RfD Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Sediment is a sink for mercury Recreation will cause an increase in pollution Seasonal mercury changes will occur due to warmer temperatures caused by a higher photosynthesis rate, higher activity rate in fishes, and higher recreational rate (pollution) Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Add Fish Sites Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Digi Prep Temperature Ambient - 180°C Uniformity ±1.0°C Over-Temp Protection Yes Time to Temperature 35 minute Ambient to 95°C Stability ±0.2°C Digestion: Methodology 10%HNO3 Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- First coil is the mixing coil Second coil is the sampling cool Hg lamp was a 254 nm Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Lamp set at 277305 Limit of Detection: 1-2 parts per trillion Drinking water, surface water, sludge, sediments and soils, foodstuff, fish and biological samples, such as tissue, blood and urine Data Collection Replicate at 1 Full Scale at 20 Integration at 10 seconds Nitrogen gas (N 2 ) set at 0.35 LPM Pump set at 3mL/min Pump Times Rinse at 35 seconds Uptake at 40 seconds Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Add photo of the AU-fluorometer YSI-Meter Temperature: plays an important role in determining the rate & extent to which chemical reactions occur Dissolved Oxygen (DO): Supersaturation can sometimes be harmful for organisms & cause decompression sickness pH: the measure of the acidity or alkalinity of a solution Salinity: s the saltiness or dissolved salt content of a body of water Total Dissolved Solids (TDS): the combined content of all inorganic & organic substances contained in a liquid which are present in a molecular, ionized or micro-granular (colloidal sol) suspended form. Turbidity: is the cloudiness or haziness of a fluid caused by individual particles (suspended solids) that are generally invisible to the naked eye 10-AU Fluorometer Chlorophyll: this reaction is how photosynthetic organisms like vegetation produce O 2 gas, & is the source for practically all the O 2 in Earth's atmosphere Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- At 10 – 15% there was a plateau on the count rate from HCl and H 2 SO 4 HCl clearly had a much greater count rate than HNO 3 and H 2 SO 4 at 254,650.5 for HCl, 127,330.3 for HNO 3 , and 193,859 for H 2 SO 4 Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Figure 30. Online Mixing: MeHg. Stennis chloride in differing percentages of HCl compared to 10 ppm MeHg with in 0.5% NaBH 4 with deionized water, 0.5% [Fe(CN) 6 ] 3- then with 0.5% NaBH 4 , H 2 O then with 2% SnCl 2 in 2% HCl, and 0.02% KMnO 4 then with 2% SnCl 2 in 2% HCl. The pump rate remained at a steady 5 mL/min and a gas flow rate of 0.30 LPM. HCl percentages: 0.5, 0.1, 0.25, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, & 5.0% Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Figure 30. Online Mixing: MeHg. Stennis chloride in differing percentages of HCl compared to 10 ppm MeHg with in 0.5% NaBH 4 with deionized water, 0.5% [Fe(CN) 6 ] 3- then with 0.5% NaBH 4 , H 2 O then with 2% SnCl 2 in 2% HCl, and 0.02% KMnO 4 then with 2% SnCl 2 in 2% HCl. The pump rate remained at a steady 5 mL/min and a gas flow rate of 0.30 LPM. HCl percentages: 0.5, 0.1, 0.25, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, & 5.0% Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Figure 30. Online Mixing: MeHg. Stennis chloride in differing percentages of HCl compared to 10 ppm MeHg with in 0.5% NaBH 4 with deionized water, 0.5% [Fe(CN) 6 ] 3- then with 0.5% NaBH 4 , H 2 O then with 2% SnCl 2 in 2% HCl, and 0.02% KMnO 4 then with 2% SnCl 2 in 2% HCl. The pump rate remained at a steady 5 mL/min and a gas flow rate of 0.30 LPM. HCl percentages: 0.5, 0.1, 0.25, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, & 5.0% Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- The pump rate remained at a steady 5 mL/min. There was not a strong flow rate-dependent response in response to acid percentage. Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Using SAS program, the surface water p-value for total mercury was 0.2042 Surface water collected monthly from the Grand Bay NERR was expected to have significant difference on a monthly basis The difference between two groups in judged to be statistically significant with the p-value = 0.05 or less Total Mercury There was a strong organic mercury-dependent response in total mercury This means that there was no significant difference on a monthly basis for total mercury in surface water since Pr > F was more than 0.05 at 0.2042 The difference between two groups in judged to be statistically significant with the p-value = 0.05 or less. There was no significant difference on a monthly basis for total mercury in surface water since Pr > F was more than 0.05 at 0.2042. Inorganic Mercury For the inorganic mercury content of the surface water samples, the p-value was 0.3881 There was no significant difference on a monthly basis for inorganic mercury in surface water since Pr > F was more than 0.05 at 0.3881 Organic Mercury For the organic mercury content of the surface water samples, the p-value was 0.6531. This means that there was no significant difference on a monthly basis for organic mercury in surface water since Pr > F was more than 0.05 at 0.6531. Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Data indicates that there was a strong inorganic mercury-dependent response in total mercury The difference between two groups in judged to be statistically significant with the p-value = 0.05 or less. Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Data represented in this figure indicates that there was a strong inorganic mercury-dependent response in total mercury These results indicate that most mercury in sediment samples was inorganic mercury Sediment collected seasonally from the Grand Bay NERR was expected to have significant difference on a seasonal basis. The difference between two groups in judged to be statistically significant with the p-value = 0.05 or less. Total mercury levels were ascertained from SnCl 2 Inorganic mercury levels were ascertained from NaBH 4 and KMnO 4 Organic mercury levels were determined by subtracting inorganic levels from total mercury levels. Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- The figures below demonstrate the differences between the surface water, sediment, and fish tissue samples on a monthly basis, each was graphed separately due to the fact that the fish samples contained substancially more mercury, therefore making a comparison difficult. Total mercury levels were ascertained from SnCl 2 Inorganic mercury levels were ascertained from NaBH 4 and KMnO 4 Organic mercury levels were determined by subtracting inorganic levels from total mercury levels. Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- The figures below demonstrate the differences between the surface water, sediment, and fish tissue samples on a monthly basis, each was graphed separately due to the fact that the fish samples contained substancially more mercury, therefore making a comparison difficult. Total mercury levels were ascertained from SnCl 2 Inorganic mercury levels were ascertained from NaBH 4 and KMnO 4 Organic mercury levels were determined by subtracting inorganic levels from total mercury levels. Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Sampling months: July 2009 to April 2010 10-AU Digital Fluorometer Surface Water Using SAS program, the difference between two groups in judged to be statistically significant with the p-value = 0.05 or less Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Sampling months: July 2009 to April 2010 Total mercury levels were ascertained from SnCl 2 , inorganic mercury levels were ascertained from NaBH 4 and KMnO 4 , and organic mercury levels were determined by substracting inorganic levels from total mercury levels The difference between two groups in judged to be statistically significant with the p-value = 0.05 or less. Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Sampling months: July 2009 to April 2010 Total mercury levels were ascertained from SnCl 2 , inorganic mercury levels were ascertained from NaBH 4 and KMnO 4 , and organic mercury levels were determined by substracting inorganic levels from total mercury levels The difference between two groups in judged to be statistically significant with the p-value = 0.05 or less. Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Sampling months: July 2009 to April 2010 Total mercury levels were ascertained from SnCl 2 , inorganic mercury levels were ascertained from NaBH 4 and KMnO 4 , and organic mercury levels were determined by substracting inorganic levels from total mercury levels The difference between two groups in judged to be statistically significant with the p-value = 0.05 or less. Fish Species: Yellowfin Mojarra, Pinfish, Sheepshead minnow, Bull minnow, Gulf pipefish, Flounder, Sailfin molly, & Gulf killifish Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Sampling months: July 2009 to April 2010 Total mercury levels were ascertained from SnCl 2 , inorganic mercury levels were ascertained from NaBH 4 and KMnO 4 , and organic mercury levels were determined by substracting inorganic levels from total mercury levels The difference between two groups in judged to be statistically significant with the p-value = 0.05 or less. Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Sampling months: July 2009 to April 2010 Total mercury levels were ascertained from SnCl 2 , inorganic mercury levels were ascertained from NaBH 4 and KMnO 4 , and organic mercury levels were determined by substracting inorganic levels from total mercury levels The difference between two groups in judged to be statistically significant with the p-value = 0.05 or less. Reference Dose per day 0.1 ug/kg/day For a 70 kg man, the reference dose is 0.001 0.1 ppb for methylmercury 2 ppb for drinking EPA’s RfD for a month 3.0 ppb (30 days) August’s organic mercury level exceeds the EPA’s RfD Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- From each sampling month, July 2009 to April 2010, the results demonstrated the mercury species, total, inorganic, and organic mercury levels Total mercury levels were ascertained from SnCl 2 , inorganic mercury levels were ascertained from NaBH 4 and KMnO 4 , and organic mercury levels were determined by substracting inorganic levels from total mercury levels The difference between two groups in judged to be statistically significant with the p-value = 0.05 or less The three major sources of mercury to surface water bodies Direct precipitation Watershed runoff (especially from wetlands) In-lake methylation of inorganic Hg Water–air exchange fluxes over water contribute to mercury buildup over water bodies The importance of these sources varies with the rates of MeHg deposition from the atmosphere, lake type, and catchment hydro logy Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- From each sampling month, July 2009 to April 2010, the results demonstrated the mercury species, total, inorganic, and organic mercury levels Total mercury levels were ascertained from SnCl 2 , inorganic mercury levels were ascertained from NaBH 4 and KMnO 4 , and organic mercury levels were determined by substracting inorganic levels from total mercury levels The difference between two groups in judged to be statistically significant with the p-value = 0.05 or less There was not a significant difference in total mercury but there was a significant difference in monthly levels of inorganic and organic mercury species in surface water Sediments: where organic and inorganic reactions occurr Sediments have an important role in mercury cycle Mercury begins to react with the different compounds in the water and a portion of it will precipitate to the sediments once it enters into the aquatic ecosystems The lifetime of mercury in sediments is so long that it can be considered as a sink for this metal Microorganisms in sediments can convert several mercury compounds into a more toxic and water-soluble form Methylmercury was easily bioavailable to and adsorbed by other aquatic organisms Due to this, most of the national programs of monitoring of the coastal and marine environment will involve the analysis of sediments Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- For the total mercury content of the surface water samples this means that there was no significant difference on a seasonal basis for total mercury Several proposed mechanisms that explain the Hg seasonal accumulation Diffusion from profundal sediments to the water column under anoxic conditions Methylation in the anoxic water column Sedimentation of catchment derived particulate MeHg and methylation in the anoxic water column Seasons: Spring (March and April), Summer (July and August), Fall (September, October, and November), and Winter (December, January, and February) Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- The relationship between chlorophyll and mercury levels will be examined to determine if chlorophyll will correlate with mercury availability using statistics Sampling months: July 2009 to April 2010 10-AU Digital Fluorometer: chlorophyll levels Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- The results analyzed the total mercury species levels from each sampling month, July 2009 to April 2010 on a site-by-site basis Mercury concentration An indicator of water pollution No significant difference for water, sediment, and fish tissue samples on a monthly basis No significant difference for surface water samples on a site-by-site basis No significant difference for sediment samples on a site-by-site basis No significant difference for fish tissue samples on a site-by-site basis Mercury accumulates in bottom sediment Released from sediments & becomes available for biogeochemical transformations Rates depend significantly on the specific environmental conditions Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- sampling months: July 2009 to April 2010 These results indicate that most mercury in fish tissue samples was organic mercury Fish species: Yellowfin Mojarra, Pinfish, Sheepshead minnow, Bull minnow, Gulf pipefish, Flounder, Sailfin molly, & Gulf killifish Fish are of environmental health interest because of the biomagnifications mercury Important pathway for human exposures Methylmercury builds up in fish tissue Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Unlike for the water and sediment samples, not all of the 13 sample sites will be used Sampling months: July 2009 to April 2010 Most mercury in fish tissue samples was methylmercury The fish samples collected from: Bayou Heron Middle Bay Bangs Lake Bayou Cumbest Point Aux Chenes Bay Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- This is the reference dosage for fish consumption The science of public health is on the threshold of a new era for determining actual exposures to environmental contaminants, this is owing to technological advances in analytical chemistry Sampling months: July 2009 to April 2010 Most mercury in fish tissue samples was methylmercury Consumption advisories Based on contaminant levels for lakes & rivers United States, Canada, & elsewhere in the world Many agencies Freshwater lakes, rivers, & coastal marine waters Consumption of fish U.S. Environmental Protection Agency (EPA) 2001 Adopted a revised reference dose (RfD) Methylmercury (MeHg) Relied on assessment conducted by the National Research Council (NRC) 0.1 ppb for methylmercury 2 ppb for drinking Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- The total mercury was highest in Summer, followed by Fall, then Winter, and lastly, Spring The atmosphere is a source of mercury to estuaries and coastal marine waters that has not been dealt with in significant detail It has been estimated that the total mass of mercury in the atmosphere is between 5000 to 6000 metric tons Mercury is transported by air masses over long distances The National Atmospheric Deposition Program (NADP) provided the total atmospheric loads This information was from the year 2008 After mapping this data using ArcView, an illustration showing the differences between seasons Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry
- Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve Melanie McHenry