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Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve:

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

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  • 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

Doctorate Dissertation Doctorate Dissertation Presentation Transcript

  • 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
  • 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 of mercury 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.
  • 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
  • Mercury Cycle
    • Aquatic systems are a reservoir of mercury containing annual flux to & 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
  • Grand Bay National Estuarine Research Reserve (GBNERR )
    • The Grand Bay Reserve is about 18,500 acres & the Grand Bay National Wildlife Refuge is 7,000 acres
      • A vast area of undeveloped coastline & marshes
      • Consists of a maze of bayous, small bays, marsh islands & mudflats
    • Anthropogenic-induced stressors
      • The population has increased in areas close which has resulted in
        • Substantial land development
        • Dredging, Spoil placement
        • Dumping of wastes
        • Impact
        • Considerable habitat loss
        • Increased chemical pollution
        • Intensified hypoxic events
  • Mercury in Surface Water
    • In 1970, sampling from U.S. lakes & rivers demonstrated that about 19% of the waterways are contaminated with mercury with a median value less than 0.5 ppb
    • Main sources of MeHg in water
    • Direct precipitation
      • Watershed runoff (especially from wetlands)
      • In-lake methylation of inorganic Hg
  • Mercury in Sediment
    • Main reservoirs are the bottom sediments
      • Sensitive indicator of the aquatic ecosystems pollution
      • Toxicity, bioaccumulation, & mobility depends on the species and chemical form
    • Concentration/Bioaccumulation
      • Accumulates in bottom sediment via sedimentation
      • An indicator of water pollution with this element
    • Methylation/Microbes
      • Inorganic Hg is transformed into methylmercury
      • Main factors are microorganisms, inorganic sulfides, iron & manganese hydroxides, redox potential, chlorides & temperature in bottom sediments
  • Mercury in Fish Muscle Tissue
    • Nearly all mercury is methylmercury >95%
    • Exposure occurs almost completely through the consumption of seafood
    • Hg vs fish species
      • Large, long-lived fish to have increased levels of mercury
      • Bioaccumulates in successive order in the food chain
      • Hg levels increase with age
    Common GBNERR Fish Grand Bay NERR Fish Species Yellowfin mojarra Gerres cinereus Pinfish Lagodon rhomboids Sheepshead minnow Cyprinodon variegates Bull minnow Fundulus grandis Gulf pipefish Syngnathus scovelli Flounder Paralichthys lethostigma Sailfin molly Poecilia latipinna Gulf Kilifish Fundulus grandis
  • Mercury in Atmosphere & Deposition
    • Atmospheric Hg is the main source of Hg in the ocean
    • Easily transported over long distances
      • The global sea-air flux of mercury is estimated between 4-13 Mmol/year
      • Regional & temporal variability depends on local wind speed, temperature, aqueous mercury concentration, & biological activity
    • Forms
      • Elemental Hg 0 is dominant form of atmospheric Hg (95%)
      • Atmospheric pool also include Hg in particulate form
  • Mercury vs Human Health Acute Exposure
        • Brain functioning
          • Irritability
          • Shyness
          • Tremors
          • Changes in hearing
          • Memory problems
        • Exposure to high levels
          • Mental retardation
          • Cerebral palsy
          • Seizures
          • Ultimately death
    Chronic Exposure
    • Central Nervous System
    • permanent damage
    • Continued Hg exposure
      • Progressive tremor
      • Erethism
      • Emotional lability
      • Memory impairment
      • Salvation, excessive sweating,
    • Potential factor of autism
  • Reference Dose (RfD)
    • Health authorities & resource managers are concerned with the risk associated with mercury exposure
    • The reference dose (RfD) that presents no risk to the public in general
    • United States Environmental Protection Agency (U.S. EPA)
      • Ingestion of Methylmercury
      • 0.1 ppb (µg/kg)
  •  
  • Rationale
    • No previous research about monitoring the concentrations of Hg at the Grand Bay National Estuarine Research Reserve (GBNERR)
    • Need data to develop strong polices for managing mercury contamination
    • Assesses spatial & temporal distribution of Hg in fish, water, & sediment from NERR
    • Assesses potential health risks associated with fish consumption
  • Goals & Objectives
    • The goal of the proposed research is to assess the spatial & temporal distribution of mercury in selected environmental samples including fish, water, sediment, & atmospheric (particulate) samples collected from the Grand Bay NERR
    • Specific objectives of this project are:
      • To develop and optimize cold vapor AAS method for mercury speciation using Leeman Labs HYDRA AA system
      • To determine total (T-Hg), inorganic (I-Hg) & methylmercury (MeHg) concentration in water, sediment, & fish samples,
      • To assess seasonal variability, relationship among surface water, sediment, fish species, sampling sites,
      • To identify if chlorophyll, an environmental factor, controlling mercury availability
      • To monitor and model the seasonal trend in atmospheric concentrations of mercury at the Grand Bay NERR
  • Hypothesis
    • Mercury levels will be higher in warmer months in surface water, sediment, and fish tissue
    • Surface water and sediment will have a direct correlation, with sediment having the highest mercury levels
    • Availability of Hg will be higher in spring and summer
    • The ambient mercury levels will not exceed the Environmental Protection Agency’s Reference Dosage (RfD)
  •  
  • Research Approach & Methods
    • Optimize the Hydra AA
      • Inorganic Mercury
      • Total Mercury
    • Select & georeference (GPS) sample collection sites
    • Perform in-situ analysis of temperature, DO, pH, Conductivity, Salinity, TDS, Turbidity
    • Collect water and sediment samples
    • Collect fish samples
      • Identify species
      • Record length & size
    • Analyze samples by CV-AAS using HYDRA AA
    • Data analysis to determine relationships between Hg concentrations & fish species
    • Perform health risk assessment based on recommended EPA assumptions
  • Materials & Methods: The Collection
  • Grand Bay NERR Sampling Sites
    • Specific JSU Sampling Sites
    • Simple Random Sampling
      • Each population unit has an equal change of being selected for measurement
    • Chosen in 2003 by Woodrey & Farah
    Sample Site Latitude Longitude GB 22 30.369037 -88.466219 GB 23 30.356549 -88.467377 GB 24 Fish Site 1 30.350465 -88.463557 GB 25 30.352468 -88.427689 GB 26 30.397086 -88.445923 GB 7 30.382192 -88.438446 GB 8 30.372279 -88.443850 GB 9 30.361141 -88.439030 GB 15 Fish Site 3 30.38455 -88.43997 GB 16 30.407844 -88.400741 GB 17 30.396774 -88.401534 Fish Site 4 30.37228 -88.44385049 GB 18 30.385505 -88.397298 Fish Site 2 30.38467 -88.40028333 GB 12 30.380090 -88.402482
  • Collection Techniques
    • Water
    • Collected into 250-mL plastic bottles
    • Filtered in lab
    • YSI Meter: Multi-parameter probe
      • Measure depth, pH, DO, turbidity, & conduct.
      • Readings taken from 1 m below surface
    • Fish
    • Sampling Seine Net, 1 inch opening, 16 feet long
    • Stored in polypropylene bag (Ziplock bag)
    • Stored on ice
    • Sediment
    • Via Sediment Grabber into plastic bag (Ziplock bag)
    • Stored on ice
    • Atmospheric Samples
    • National Atmospheric Deposition Program (NADP) 2008
  • Materials & Methods: Sample Analysis
  • Digestion : Digi Prep MS (from SCP Science)
    • Teflon digestion tubes
    • Digestion of Sediment Samples
      • 0.5-1 g of soil in 4 mL of HCl
      • Digested 4 h at 160 o C
      • Dilute to 50 mL in water
    • Water Samples
      • Filtered with 0.45 µm filters into 50 mL tubes and acidified to 5% HCl
    • Digestion of Fish Samples
      • 0.5-1g of tissue digested in 4 mL HCl
      • Digested 3-4 h at 160 o C
      • Dilute to 50 mL
  • Cold Vapor Atomic Absorption (CVAAS) for Hg
    • HYDRAA AA manifiold for Hg speciation
    • Compliant with EPA protocols for Hg speciation
    • Sample flow - 3 mL/min
    • Oxidant flow – 1.5 mL/min
    • Reductant flow – 1.5 mL/min
    • N 2 set at 0.35 liter/min
      • Rinse at 35 seconds
      • Uptake at 40 seconds
    N 2 Hg(0) AAS cell Waste Sample Oxidant Reductant Hg lamp
  • Total and Inorganic Hg detection
    • Total Mercury Determination
    • Inorganic Hg Determination
    Inorganic Hg : Sample mixed water and reacted with 1% SnCl 2 Total Hg : Sample mixed 0.1% KMnO 4 (oxidant) and reacted with 0.5% NaBH 4 Sample H 2 O SnCl 2 Sample KMnO 4 NaBH 4
  • Additional Parameter Analysis
    • Conducted with the YSI-meter at site or analyzed with the 10-AU Fluorometer
    • YSI-Meter
    • Temperature
    • Dissolved Oxygen (DO)
    • pH
    • Salinity
    • Total Dissolved Solids (TDS)
    • Turbidity
    • 10-AU Fluorometer
    • Chlorophyll
  • Materials & Methods: Data Analysis
  • Data Analysis
    • Statistical Analysis System: SAS
    • SAS: a powerful tool for analysis of data
    • Contains an extensive library of statistical procedure or PROCs
      • PROC CORR - descriptive statistics
      • PROC FREQ - counts of number cases
      • PROC MEANS - descriptive statistics (sample size, mean, variance, standard deviation, range, and minimum and maximum)
      • PROC ANOVA - analysis of variance for balanced data from a wide variety of experimental designs
    • ArcView
    • It is an analytical tool
    • Attribute Data into Arc/INFO
      • Create a new INFO data file to hold the attributes
      • Add the attribute values to the newly created INFO data file
      • Relate or join the attributes in the INFO data to the feature attribute table in order to manage the database
    • Geographic features using real-world coordinates are recorded
    • Related coverage in one common coordinate system must be stored
  • Results
  • CVAAS: Optimization of Acidity
    • Absorbance from Hg via Hydrochloric and Nitric acids
    • For percentages over 4% of acid, HCl had a greater count rate
    • These results indicate that at 10% level, all acids were more effective .
    • Data represented in figure indicates a strong concentration-dependent response
    • Hydrochloric acid had a greater overall effect than nitric acid
  • CVAAS: Effect of HCl
    • 10 ppb In-Hg or MeHg in different HCl solutions mixed with water and KMnO 4
    • followed by reduction by SnCl 2 or NaBH 4 , respectively.
    • 1% HCl acidity is sufficient for both MeHg and In-Hg with suitable reductants
    • MeHg does not react without NaBH 4 . Oxidation to inorganic Hg with KMnO 4
    • is essential before reduction to elemental Hg 0 .
  • CVAAS: Effect of NaBH 4
    • 10 ppb In-Hg or MeHg in 2% HCl treated either with NaBH 4 and DI or NaBH 4 and KMnO 4
    • 0.4-0.6% NaBH 4 appears to be sufficient for complete reduction of MeHg.
  • CVAAS: Effect of SnCl 2
    • 10 ppb In or MeHg in 2% HCl treated either with SnCl 2 and DI or SnCl 2 and KMnO 4
    • SnCl 2 does not affect MeHg even in the presence of KMnO 4 .
  • CVAAS: Optimization of N 2 Flow rate
    • Obtain highest signals by controlling the residence time of Hg 0 in light path
    • Flow rates below 0.3 LPM, there was an increase in the response via count rate
    • These results indicate that optimum signal could be obtained around 0.3 LPM without experiencing memory effects
    • Flow rates below 0.30 LPM were not suitable for cleaning the system. Memory effects dominate.
  • Mercury in Surface Water
    • October had the highest amount of all mercury species
    • Statistical analysis for monthly variation
    • Total Hg: No significant differences (P = 0.2042)
    • In-Hg: No significant differences (P = 0.3881)
    • MeHg: No significant differences (P = 0.6531):
    • Sampling: July 2009 to April 2010
    • In-Hg was ascertained from SnCl 2 , total Hg levels were ascertained from NaBH 4 and KMnO 4 . Organic mercury levels were determined by subtracting In-Hg from total Hg levels
  • Mercury in Sediment Samples
    • Hg in sediments was mostly inorganic
    • Statistical analysis for Monthly variation
    • Tot-Hg: No significant variation (P = 0.2042)
    • In-Hg: Significant variation
    • (P = 0.0212)
    • MeHg: Significant variaition
    • (P = 0.0128)
    • Sampling months: July 2009 to April 2010
    • In-Hg was ascertained from SnCl 2 , total Hg were ascertained from NaBH 4 and KMnO 4 .
    • Organic Hg levels were determined by subtracting inorganic levels from total mercury levels.
  • Seasonal Variability of Hg in Surface Water
    • Tot Hg: Variations are not significant (P=0.4969)
    • In-Hg: Variations are not significant (P=0.2718)
    • MeHg: Variations are not significant (P=0.1695)
    • Seasons : Spring (March and April), Summer (July and August), Fall (September, October, and November), and Winter(: December, January, and February)
  • Seasonal Variability of Hg in Sediment
    • Tot-Hg: Variations are significant (P = 0.0208)
    • In-Hg: Variations are significant (P = 0.0212)
    • MeHg: Variations are significant (P = 0.0128)
    Seasons: Spring (March and April), Summer (July and August), Fall (September, October, and November), and Winter(: December, January, and February)
  • Seasonal Variability of Hg in Fish
    • Tot. Hg: no significant difference (P = 0.2489)
    • In-Hg: no significant difference (P = 0.2516)
    • MgMe: no significant difference (P = 0.3517)
    Seasons : Spring (March and April), Summer (July and August), Fall (September, October, and November), and Winter(: December, January, and February)
  • Chlorophyll vs Hg Availability
    • Strong chlorophyll-dependent response in Febr. and a smaller peak in Sept.
    • Site-by-Site: No significant difference (P = 0.1925)
    • Tot-Hg: No significant differences water, sediment, and fish tissue (P = 0.5905)
  • Hg Levels in Tissues of Fish collected from NERR Monthly variation
    • Strong inorganic mercury-dependent response in total mercury
    • Most Hg is organic mercury
      • Total (P = 0.646), & Organic (P = 0.1592) Hg levels did not vary significantly
      • Inorganic Hg varied significant (P= 0.0181)
  • Hg Levels in Tissues of Fish collected from NERR Variation across Sites
    • Tot-Hg: not a significant difference (P=0.646)
    • In-Hg: significant differences among sites (P=0.0181)
    • MeHg: not a significant difference (P=0.1592)
  • Relationship among Surface Water, Sediment, & Fish Tissue
    • Total Hg = No significant difference on a site-by-site basis (P= 0.5905) among surface water, sediment, & fish tissue
    • No significant difference in surface Water (P = 0.3012), Sediment (P = 0.3053), and Fish Tissue (P = 0.3700)
  • Mercury Concentrations in Fish Species
    • Different species were expected to have differences in Hg levels
    • No significant differences in Total Hg (P=0.5647), In-Hg (P=0.2685), & MeHg (P=0.3921)
    • Most Hg was organic form
    • Site-by-site variation are not significant for: Yellowfin (P= 0.5419), Pinfish (P= 0.9166), Sheepshead (P= 0.0710), Bull minnow (P= 0.3093), Flounder (P= 0.6747), and Sailfin molly (P= 0.8619)
    • Not Significant for: Gulf pipefish (P = <0.0001) and Gulf kilifish (P = 0.0010)
  • Mercury Concentrations in Fish Sampling Sites
    • Total Hg: No significant difference on a site-by-site basis (P=0.0575)
    • In-Hg: No significant difference on a site-by-site basis (P=0.2047)
    • MeHg: Significant difference on a site-by-site basis (P = 0.0227)
    • Strong inorganic Hg-dependent response in total mercury
    • Most Hg in fish tissue samples was organic mercury
  • Monthly Mercury Levels associated with Fish Consumption
    • Fish tissue samples collected monthly from the NERR was expected to have significant difference from the EPA’s reference dosage (RfD)
      • 0.1 ppb for MeHg
      • Ingestion
    • There was a strong inorganic mercury-dependent response in total mercury.
    • Most mercury in fish tissue samples was organic mercury
    • Significant difference among species for Total Hg (P < 0.0001)
  • Seasonal Trend in Atmospheric Levels of Hg at the Grand Bay NERR
    • Monitor
    • Monthly Hg levels are not significantly different (P=0.8041)
    • Seasonal Hg levels are not significantly different (P=0.7061)
    • Model
    • National Atmospheric Deposition Program (NADP), newest data: 2008
    • Mapped using ArcView after obtaining a raster image from Maris of the Grand Bay National Estuarine Research Reserve
    • ArcView used to illustrate the special and temporal changes in atm Hg between seasons
  •  
  • Mercury Concentrations in Filtered Surface Water
    • Results indicate that October had the highest amount of all mercury species
    • Surface Water: Total, Inorganic, & Organic Hg were not significantly different
    Month Total (ppb) Inorganic (ppb) Organic (ppb) July 0.09 ± 0.002 0.001 ± 0.001 0.008 ± 0.003 Aug 0.01 ± 0.002 0.002 ± 0.001 0.008 ± 0.001 Sept 0.01 ± 0.001 0.005 ± 0.001 0.006 ± 0.001 Oct 0.026 ± 0.007 0.005 ± 0.004 0.021 ± 0.004 Nov 0.01 ± 0.001 0.002 ± 0.001 0.009 ± 0.001 Dec 0.012 ± 0.002 0.003 ± 0.001 0.008 ± 0.002 Jan 0.006 0.005 0.001 ± 0.001 Feb 0.009 ± 0.001 0.001 0.008 ± 0.001 Mar 0.011 ± 0.001 0.000 0.011 ± 0.001 Apr 0.072 ± 0.246 0.000 0.072 ± 0.246
  • Mercury Concentrations in Sediment Samples
    • Results indicate that October was the month that had the highest amount of all mercury species
    • Sediment: Total mercury was not significantly different, however, Inorganic and Organic mercury were not significantly different
    Month Total (ppb) Inorganic (ppb) Organic (ppb) July 0.001 ± 0.001 0.001 ± 0.001 0.001 ± 0.001 Aug 0.001 0.001 0.000 Sept 0.000 0.000 0.000 Oct 0.001 ± 0.001 0.000 0.000 Nov 0.001 ± 0.001 0.001 0.000 Dec 0.001 ± 0.001 0.001 0.000 Jan 0.001 ± 0.002 0.001 ± 0.002 0.000 Feb 0.001 ± 0.002 0.000 0.000 Mar 0.001 0.001 0.000 Apr 0.002 ± 0.001 0.001 ± 0.002 0.000
  • Seasonal Variability of Surface Water, Sediment, and Fish Samples
    • Environmental matrices collected seasonally were expected to have significant difference
    • Surface Water:
      • Total, Inorganic, & Organic mercury: no significant difference
      • On a seasonal basis, there was no significant difference in mercury species concentration
    • Sediment
      • Total, Inorganic, & Organic mercury: significant difference
      • On a seasonal basis, there was a significant difference in mercury species concentration
    • Fish Tissue
      • Total, Inorganic, &Organic mercury: no significant difference
      • On a seasonal basis, there was no significant difference in mercury species concentration
    Total Hg (ppb) Inorganic Hg (ppb) Organic Hg (ppb) Water Sediment Fish Water Sediment Fish Water Sediment Fish Summer 0.019±0.004 0.002±0.001 6.11±1.334 0.003±0.002 0.001±0.001 2.42±0.252 0.016±0.004 0.001±0.001 3.69±1.15 Fall 0.015±0.003 0.001±0.001 2.37±0.804 0.004±0.002 0.000 1.15±0.445 0.012±0.002 0.000 1.36±0.73 Winter 0.009±0.001 0.001±0.001 2.45±0.609 0.003 0.001±0.001 1.23±0.387 0.006±0.001 0.000 1.52±0.61 Spring 0.009±0.002 0.001±0.001 1.13±0.632 0.000 0.001±0.001 0.676±0.406 0.009±0.002 0.000 0.456±0.249
  • Chlorophyll versus Mercury Availability
    • Strong chlorophyll-dependent response in February & a smaller peak in Sept.
    • No significant differences on a site-by-site basis for surface water, sediment, and fish tissue samples
    Total Hg (ppb) Inorganic Hg (ppb) Organic Hg (ppb) Month Chlorophyll (ppb) Surface Water Sediment Fish Surface Water Sediment Fish Surface Water Sediment Fish July 0.731±0.463 0.09±0.002 0.001±0.001 0.696±0.285 0.001±0.001 0.001±0.001 0.173±0.03 0.008±0.003 0.001±0.001 0.524±0.264 Aug 0.813±0.524 0.01±0.002 0.001 5.42±1.052 0.002±0.001 0.001 2.25±0.222 0.008±0.001 0.000 3.16±0.895 Sept 1.14±0.632 0.01±0.001 0.000 2.31±0.871 0.005±0.001 0.000 1.38±0.758 0.006±0.001 0.000 0.928±0.523 Oct 0.736±0.505 0.026±0.007 0.001±0.001 2.71±1.03 0.005±0.004 0.000 1.13±0.123 0.021±0.004 0.000 1.57±0.997 Nov 0.583±0.473 0.01±0.001 0.001±0.001 2.104±0.513 0.002±0.001 0.001 0.956±0.455 0.009±0.001 0.000 1.59±0.671 Dec 0.287±0.234 0.012±0.002 0.001±0.001 2.31±0.696 0.003±0.001 0.001 1.41±0.293 0.008±0.002 0.000 0.904±0.481 Jan 1.44±0.662 0.006 0.001±0.002 2.06±0.426 0.005 0.001±0.002 1.15±0.434 0.001±0.001 0.000 1.83±0.678 Feb 1.98±0.818 0.009±0.001 0.001±0.002 2.991±0.704 0.001 0.000 1.15±0.434 0.008±0.001 0.000 1.83±0.678 Mar 1.43±0.595 0.011±0.001 0.001 0.897±0.896 0.000 0.001 0.471±0.497 0.011±0.001 0.000 0.425±0.403 Apr 0.889±0.363 0.072±0.246 0.002±0.001 1.36±0.368 0.000 0.001±0.002 0.88±0.315 0.072±0.246 0.000 0.488±0.095
  • Relationship between Surface Water, Sediment, & Fish Tissue
    • No significant differences for surface water, sediment, and fish tissue samples on a monthly basis
    • No significant differences for surface water, sediment, and fish samples on a site-by-site basis
    Total Hg (ppb) Inorganic Hg (ppb) Organic Hg (ppb) Month Surface Water Sediment Fish Tissue Surface Water Sediment Fish Tissue Surface Water Sediment Fish Tissue July 0.09±0.002 0.001±0.001 0.696±0.285 0.001±0.001 0.001±0.001 0.173±0.03 0.008±0.003 0.001±0.001 0.524±0.264 Aug 0.01±0.002 0.001 5.42±1.052 0.002±0.001 0.001 2.25±0.222 0.008±0.001 0.000 3.16±0.895 Sept 0.01±0.001 0.000 2.31±0.871 0.005±0.001 0.000 1.38±0.758 0.006±0.001 0.000 0.928±0.523 Oct 0.026±0.007 0.001±0.001 2.71±1.03 0.005±0.004 0.000 1.13±0.123 0.021±0.004 0.000 1.59±0.997 Nov 0.01±0.001 0.001±0.001 2.10±0.513 0.002±0.001 0.001 0.956±0.455 0.009±0.001 0.000 1.59±0.671 Dec 0.012±0.002 0.001±0.001 2.31±0.696 0.003±0.001 0.001 1.41±0.293 0.008±0.002 0.000 0.904±0.481 Jan 0.006 0.001±0.002 2.06±0.426 0.005 0.001±0.002 1.15±0.434 0.001±0.001 0.000 1.83±0.678 Feb 0.009±0.001 0.001±0.002 2.99±0.704 0.001 0.000 1.15±0.434 0.008±0.001 0.000 1.83±0.678 Mar 0.011±0.001 0.001 0.897±0.896 0.000 0.001 0.471±0.497 0.011±0.001 0.000 0.425±0.403 Apr 0.072±0.246 0.002±0.001 1.36±0.368 0.000 0.001±0.002 0.88±0.315 0.072±0.246 0.000 0.488±0.095
  • Mercury Concentrations in Fish Species
    • N o significant difference in Yellowfin, Pinfish, Sheephead minnow, Bull minnow, Flounder, and Sailfin Molly, but significant difference Gulf pipefish and Gulf kilifish
    • No significant differences for Total, Inorganic, and Organic mercury on species basis
    Species Total (ppb) Inorganic (ppb) Organic (ppb) Yellowfin mojarra 0.409 ± 0.036 0.132 ± 0.017 0.277±0.053 Pinfish 2.46 ± 2.06 0.756 ± 0.415 1.713±1.886 Sheepshead Minnow 1.64 ± 1.02 0.641 ± 0.523 1.006±4.959 Bull Minnow 1.73 ± 1.63 0.651 ± 0.611 1.085±4.065 Gulf Pipefish 0.373 ± 1.75 0.100 ± 0.822 0.273±1.878 Flounder 1.54 ± 1.105 0.103 ± 0.12 1.438±1.309 Sailfin Molly 1.57 ± 0.63 0.467 ± 0.222 1.106±0.451 Gulf Kilifish 3.39 ± 1.67 0.915 ± 0.816 2.475±2.016
  • Mercury Concentrations in Fish Sampling Sites
    • 4 sites selected based on:
      • Accessibility of the boat
      • Depth of the areas
    • Total Hg- No significant difference on a site-by-site basis
    • In-Hg- No significant difference on a site-by-site basis
    • MeHg- significant difference on a site-by-site basis
    Site Average Total (ppb) Inorganic (ppb) Organic (ppb) FS1 2.30 ± 1.39 1.04 ± 0.830 1.42 ± 1.00 FS2 1.88 ± 1.30 0.9 ± 0.613 1.05 ± 0.836 FS3 2.79 ± 1.38 1.27 ± 0.538 1.60 ± 0.985 FS4 2.17 ± 1.67 1.17 ± 0.610 1.23 ± 1.15
  • Potential Health Risk associated with Fish Consumption
    • Reference Dosage (RfD)
      • Based on neurologic developmental effects
      • Measured in children associated with exposure in utero to MeHg from maternal diet
    • For organic mercury, there is a significant difference on a monthly basis
    Month Organic (ppb) EPA's RfD July 0.524 ± 0.264 0.1 August 3.168 ± 0.895 0.1 September 0.928 ± 0.523 0.1 October 1.579 ± 0.997 0.1 November 1.594 ± 0.671 0.1 December 0.904 ± 0.481 0.1 January 1.839 ± 0.678 0.1 Febuary 1.839 ± 0.678 0.1 March 0.425 ± 0.403 0.1 April 0.488 ± 0.095 0.1
  • Seasonal Trend in Atmospheric Concentrations of Hg at NERR
    • Atmospheric analysis were expected to have significant difference on
    • monthly and seasonal basis
    • Total mercury was highest in Summer
    • Hg content of atmospheric samples, the p-value was 0.7061 which means that there was not a significant difference on a monthly basis for total mercury
    Month Total Hg (ppb) Jul 12.5 ± 6.02 Aug 19.1 ± 6.47 Sept 12.0 ± 2.92 Oct 9.14 ± 1.26 Nov 8.35 ± 8.46 Dec 6.92 ± 2.09 Jan 8.67 ± 4.03 Feb 8.36 ± 10.5 Mar 5.44 ± 9.46 Apr 8.67± 5.59
  •  
  • Conclusions
    • Monthly carrying loads of inorganic and organic Hg varied significantly for surface water and sediment
    • These values were not stable, unlike total mercury
    • Hg loads did not flux seasonally or on a site-by-site basis for surface water, sediment, or fish tissue
    • Chlorophyll did not change at a rate significantly different from Hg levels in surface water and sediment, suggesting there is a possible link
    • Fish tissue - monthly carrying loads of organic Hg vary significantly, unlike total and inorganic mercury
    • Species effect - No significant differences on a species basis for fish tissue
    • Monthly Hg levels in fish were found to be statistically different from EPA’s RfD
    • Atmospheric Hg levels only differed on a monthly basis for organic Hg
    • No significant monthly differences in the carrying load of total or inorganic Hg
    • Atmospheric levels of Hg did not differ on a seasonal basis.
  • Special Thanks
    • Zikri Arslan
    • Professor of Environmental Chemistry
    • Paul Tchounwou , Sc.D., F.A.B.I., I.O.M.
    • Professor, Chair & Director Environmental Science Ph.D. Program
    • Yerramilli Anjaneyulu
    • Professor of Chemistry, Director, GIS Remote Sensing
    • Latoya Myles
    • Physical Scientist with the Air Resources Laboratory’s Atmospheric Turbulence & Diffusion Division (ATDD)
    • Hyun Jung Cho
    • Associate Sensing & GIS
    • Stephen Kishini
    • NOAA PhD Student
    • Christina Watters
    • ECSC Coordinator
    • Paulette Bridges
    • Hilliard Lackey
    • Dr. Mark Hardy
    • Dr. Greg Begonia
  • Acknowledgements
    • This research was supported, in part, by a grant from the National Oceanic & Atmospheric Administration grant # NA17AE1626, Subcontract # 27-0629-017, through the Environmental Cooperative Science Center at Florida A&M University to Jackson State University and the support of the Atmospheric Deposition Program of the Trent Lott Geospatial and Visualization Research Center
  • Any Questions
  • 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