Doctorate Dissertation
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Transcript of Doctorate Dissertation
DissertationMelanie McHenrySeptember 2010
Expected Graduation Date: December 2010Environmental 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 Mercury is present in the environment in different forms that have biogeochemical different forms that have biogeochemical transformation and ecotoxicity.transformation and ecotoxicity.
• Mercury is one of the most hazardous pollutants Mercury is one of the most hazardous pollutants in the marine environment.in the marine environment.
• All forms of mercury can have adverse health All forms of mercury can have adverse health effects at sufficiently high doses.effects at sufficiently high doses.
• Organic mercury compounds are of particular Organic mercury compounds are of particular concern because of their enhanced toxicity, concern because of their enhanced toxicity, lipophilicity, and bioaccumulation in tissues.lipophilicity, and bioaccumulation in tissues.
22
Organic MercuryMost toxic because they are lipophilic & can penetrate
the blood brain barrier (BBB), invade the nervous system
Inorganic MercuryIngestion is usually inadvertent or with suicidal
intent & gastrointestinal ulceration or perforation & hemorrhage have been rapidly produced it
will followed by circulatory collapse
Elemental MercuryVolatile at room temperature
After inhalation, pass through pulmonary, enter blood and distribute to red blood cells,
central nervous system (CNS), & kidneys
33
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
44
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 wastesImpact• Considerable habitat loss• Increased chemical pollution• Intensified hypoxic events
55
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 precipitationWatershed runoff (especially from
wetlands)In-lake methylation of inorganic Hg
66
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
77
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
88
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 Hg0 is dominant form of atmospheric Hg (95%)– Atmospheric pool also include Hg in particulate form
99
Mercury vs Human Health
1010
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 Systempermanent 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)
1111
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
1313
Goals & ObjectivesThe 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
1414
Specific objectives of this project are:
1. To develop and optimize cold vapor AAS method for mercury speciation using Leeman Labs HYDRA AA system
2. To determine total (T-Hg), inorganic (I-Hg) & methylmercury (MeHg) concentration in water, sediment, & fish samples,
3. To assess seasonal variability, relationship among surface water, sediment, fish species, sampling sites,
4. To identify if chlorophyll, an environmental factor,
controlling mercury availability
5. 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)
1515
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
1717
Materials & Methods: The Collection
Grand Bay NERRSampling Sites
Sample Site Latitude Longitude
GB 22 30.369037 -88.466219
GB 23 30.356549 -88.467377GB 24
Fish Site 130.350465 -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 -88.439030GB 15
Fish Site 330.38455 -88.43997
GB 16 30.407844 -88.400741
GB 17 30.396774 -88.401534Fish Site 4 30.37228 -88.44385049
GB 18 30.385505 -88.397298Fish Site 2 30.38467 -88.40028333
GB 12 30.380090 -88.402482
• 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
Collection TechniquesWater• 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
2020
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 160oC
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 160oC
– Dilute to 50 mL
2222
Cold Vapor Atomic Absorption (CVAAS) for Hg
• HYDRAA AA manifiold for Hg speciation
• Compliant with EPA protocols for Hg speciation
N2
Hg(0)
AAS cell
Waste
Sample
Oxidant
Reductant
Hg lamp
• Sample flow - 3 mL/min
• Oxidant flow – 1.5 mL/min
• Reductant flow – 1.5 mL/min
• N2 set at 0.35 liter/min
– Rinse at 35 seconds
– Uptake at 40 seconds
Total and Inorganic Hg detectionTotal Mercury Determination
Inorganic Hg: Sample mixed water and reacted with 1% SnCl2
Total Hg: Sample mixed 0.1% KMnO4 (oxidant) and reacted with 0.5% NaBH4
Inorganic Hg Determination
Sample
H2O
SnCl2
Sample
KMnO4
NaBH4
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
2525
Materials & Methods: Data Analysis
Data AnalysisStatistical 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
2727
ResultsResults
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 KMnO4
followed by reduction by SnCl2 or NaBH4, respectively.
1% HCl acidity is sufficient for both MeHg and In-Hg with suitable reductants
MeHg does not react without NaBH4. Oxidation to inorganic Hg with KMnO4 is essential before reduction to elemental Hg0.
0
100000
200000
300000
400000
0 1 2 3 4 5 6
HCl conc (%)
Sig
na
l
10ppb MeHg-0.5% KMnO4-0.5% NaBH4
10ppb-H2O-0.5% NaBH4
10ppb MeHg-0.5% KMnO4-2% SnCl2
10ppb In-Hg-H2O-2% SnCl2
10ppb InHg-H2O-0.5% NaBH4
CVAAS: Effect of NaBH4
10 ppb In-Hg or MeHg in 2% HCl treated either with NaBH4 and DI or NaBH4 and KMnO4
0.4-0.6% NaBH4 appears to be sufficient for complete reduction of MeHg.
0
100000
200000
300000
0 0.2 0.4 0.6 0.8 1 1.2
NaBH4 (%)
Sig
na
l 10 ppb Hg-H2O-NaBH4
10 ppb MeHg-0.2% KMnO4 -NaBH4
10 ppb MeHg-H2O-NaBH4
CVAAS: Effect of SnCl2
10 ppb In or MeHg in 2% HCl treated either with SnCl2 and DI or SnCl2 and KMnO4
SnCl2 does not affect MeHg even in the presence of KMnO4.
0
100000
200000
300000
400000
0 1 2 3 4 5 6
SnCl2 (%) in 2% HCl
Sig
nal 10 ppb Hg-H2O-SnCl2
10 ppb MeHg-H2O-SnCl2
10 ppb MeHg-0.2% KMnO4-SnCl2
10 ppb In-Hg-0.2% KMnO4-SnCl2
CVAAS: Optimization of N2 Flow rate
• Obtain highest signals by controlling the residence time of Hg0 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 SnCl2, total Hg levels were ascertained from NaBH4 and KMnO4. 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 SnCl2, total Hg were ascertained from NaBH4 and KMnO4. •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 NERRMonthly 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 ± 0.003Aug 0.01 ± 0.002 0.002 ± 0.001 0.008 ± 0.001Sept 0.01 ± 0.001 0.005 ± 0.001 0.006 ± 0.001Oct 0.026 ± 0.007 0.005 ± 0.004 0.021 ± 0.004Nov 0.01 ± 0.001 0.002 ± 0.001 0.009 ± 0.001Dec 0.012 ± 0.002 0.003 ± 0.001 0.008 ± 0.002Jan 0.006 0.005 0.001 ± 0.001Feb 0.009 ± 0.001 0.001 0.008 ± 0.001Mar 0.011 ± 0.001 0.000 0.011 ± 0.001Apr 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 ± 0.001Aug 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 0.000Mar 0.001 0.001 0.000Apr 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)
MonthChlorop
hyll (ppb)
Surface Water
Sediment Fish Surface Water
SedimentFish
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)
MonthSurface Water
SedimentFish
TissueSurface Water
Sediment Fish Tissue
Surface Water
SedimentFish
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
• No 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 ThanksZikri ArslanProfessor of Environmental ChemistryPaul Tchounwou , Sc.D., F.A.B.I., I.O.M.Professor, Chair & Director Environmental Science Ph.D. ProgramYerramilli AnjaneyuluProfessor of Chemistry, Director, GIS Remote Sensing Latoya MylesPhysical Scientist with the Air Resources Laboratory’s Atmospheric Turbulence & Diffusion Division (ATDD)Hyun Jung ChoAssociate Sensing & GISStephen KishiniNOAA PhD StudentChristina WattersECSC CoordinatorPaulette BridgesHilliard LackeyDr. Mark HardyDr. Greg Begonia
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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
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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
ChemicalOther Onsite
LandfillsSubtotal
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