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Published byConnor Hicks Modified over 10 years ago
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Selenium Naturally occurring metalloid Associated with: Coal seams Phosphate deposits Other mineral formations
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Increased mobilization due to: Irrigation Sewage Fly ash/coal combustion Mining
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4 Oxidation states Selenite (SeO 3 -2 ) Selenate (SeO 4 -2 ) Selenides (Se -2 ) Elemental selenium (Se) Insoluble Poorly assimilated by aquatic plants
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Immobilized Selenate is oxidized to Selenite Selenite binds to: Clay Organic particles Forms precipitate with iron Precipitate settles out Sediment can be buried Remobilized by: Plant root absorption Consumption by inverts and fish
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Benefits: Protects DNA, lipids, and proteins If fish are deficient: Loss coordination Reduced growth Reduced immune response
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Impairs gas exchange Swollen lamellae Constricts blood vessels Binds to hemoglobin Unable to carry oxygen Induce cataracts Edema Seleno-proteins
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Similar to sulfides Cells cannot discriminate Selenium substituted for sulfur Results in dysfunctional amino acids/proteins Accumulates in gonads, kidney, and liver
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Seleno-proteins stored in ovarian tissues Proteins transferred to eggs Building blocks for tissue synthesis Metabolic fuel External feeding Critical period High mortality
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Faulty proteins used for development Results in teratogenesis: Craniofacial deformities Spinal deformities Missing fins Edema Inability to feed leading to death
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Kyphosis Lordosis Scoliosis
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1) Determine the effects of selenium on the aquatic ecosystem of the Upper Mud River Watershed, WV 2) Determine the effects of selenium on the survival of bluegill larvae
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Lower Guyandotte River Watershed Lincoln and Boone Counties, WV 124 ha reservoir 4.5-6 m depth Inhabitants: Bluegill Largemouth bass Crappie Channel catfish
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Paint Creek Watershed Fayette County, WV 81.75 ha reservoir 12.2 m depth Inhabitants: Bluegill Largemouth bass Channel catfish White crappie
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October 2008-November 2010 Mud River (main stem and tributaries) 20 total sites Mined (13) Unmined (7) Reference Site 2 sites
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Water quality
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Plum Orchard Lake (Reference Site)
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YSI: DO, pH, temperature, conductivity Total and dissolved Fe, total Se, TDS, sulfates, alkalinity, hardness, TSS and TOC Picture credit: Melissa ONeal
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July 2009 Stantec, Inc. Stream (13) Reservoir (5) Transects Top 5 cm Picture credit: Stantec, Inc., Lexington, KY
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July, August, September 2010 Mud River Reservoir (2) Reference Site (1) 10-20 min/ tow Surface and mid depth 95% ethanol
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November 2009 and 2010 Mud River (11) Reference Site (2) 2009: 4 kick samples 2010: 6-8 kick samples Sorted into functional feeding group (FFG) Photo credit: Melissa ONeal
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June 2009 and 2010 Spawning Mud River Reservoir Whole Body (n=118) Gonad (n=31) Reference Site Whole Body (n=86) Gonad (n=10) Egg selenium calculated Photo credit: John Howell
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June 2009 and 2010 2009: Entire redd collected 2010: Only shells, rocks, and branches Individual redds collected Transported to WVU wet lab
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Nest split into tanks A Tanks: 28 day early life stage test for chronic toxicity B Tanks: 9 day swim-up success Tanks contained water from original location 3-days after hatching fed fine fish food and brine shrimp twice daily
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Multiple full water changes done daily Ammonia (daily) Nitrite, alkalinity, hardness (weekly) Temperature, DO, and pH (subset daily)
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VariableMinedUnminedReference Temperature ( o C) 14.19 ± 0.42 a 13.60 ± 0.57 a 17.83 ± 1.45 b Conductivity (µs/cm) 1059.93 ± 33.91 a 152.23 ± 7.16 b 38.38 ± 0.66 c pH 7.77 ± 0.02 a 7.26 ± 0.05 b 7.05 ± 0.09 b DO (mg/L) 8.91 ± 0.32 a 8.23 ± 0.20 a 9.63 ± 1.88 a Hardness (mg/L CaCO 3 ) 640.81 ± 31.91 a 60.14 ± 5.49 b 13.35 ± 0.302 c Alkalinity (mg/L CaCO 3 ) 159.45 ± 5.54 a 37.09 ± 2.05 b 16.87 ± 1.37 c
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VariableMinedUnminedReference TDS (mg/L) 1416.57 ± 217.61 a 139.16 ± 16.52 b 16.87 ± 1.37 c Sulfate (mg/L) 462.24 ± 17.11 a 39.87 ± 8.64 b 12.14 ± 0.64 c Dissolved Iron (mg/L) 0.068 ± 0.007 a 0.131 ± 0.009 b 0.208 ± 0.023 c Total Iron (mg/L) 0.606 ± 0.189 a 0.566 ± 0.093 ab 0.336 ± 0.037 b Total Selenium (µg/L) 6.52 ± 0.289 a 0.262 ± 0.015 b 0.194 ± 0.021 b TOC (mg/L) 3.46 ± 0.36 a 3.22 ± 0.308 a 3.15 ± 0.079 a
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a a Site Type Unmined Mined Selenium (µg/g DW) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 a a
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a a a a a
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a a b
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Site FiltererGathererScraperShredderComposite Unmined 2.69 ± 0.4 a 3.90 ± 1.0 a 3.7 ± 0.52 a 1.9 ± 0.72 a 3.4 ± 0.42 a Mined 11.7 ± 1.4 b 12.44 ± 1.8 b 8.1 ± 0.93 b 11.5 ± 2.45 b 11.1 ± 0.87 b Reference N/A2.67 ± 0.04 a N/A0.88 ± 0.12 a 2.1 ± 0.50 a
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* Mud ReservoirReference 0 5 10 15 20 25 30 35 Site Selenium (µg/g DW) a b
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* Mud ReservoirReference 0 5 10 15 20 25 30 Site Selenium (µg/g DW) a b
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VariableReference Mud River Reservoir Temperature ( o C) 21.41 ± 0.12*22.69 ± 0.12 Dissolved O 2 (mg/L) 7.87 ± 0.097.99 ± 0.05 pH 7.73 ± 0.03*8.36 ± 0.008 Ammonia (mg/L) 0.766 ± 0.059*0.308 ± 0.041 Nitrite (mg/L) 0.01 ± 0.001*0.017 ± 0.002 Hardness (mg/L CaCO 3 ) 20 ± 0.0*250 ± 0.0 Alkalinity (mg/L CaCO 3 )16.35 ± 1.13*80 ± 0.0
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The mine boundary is a good delineation for site types Sites in the mine and downstream were of high (> 5 µg/L) or moderate hazard (3-5 µg/L) based on the hazard profile by Lemly (1995) Levels as low as 2 µg/L can be bioaccumulated in the food chain and cause reproductive failure
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All sediment samples considered no to low hazard ( 2 µg/g DW) Reservoir transects All samples also considered low to no hazard at < 2 µg/g DW Selenium seems to remain in the water column
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Mud River Reservoir (mined and unmined) sites differed from the reference site Not sorted to species (zooplankton, etc.)
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Mined areas greater than dietary threshold for fish (3 µg/g) and birds (7 µg/g) Did not see a significant difference between the reference site and unmined sites
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No hazard category for whole body/gonad selenium concentrations Egg selenium (68.76 ± 1.95 µg/g ) High hazard (>20 µg/g)
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Reference Mud Reservoir Toxic Effect Threshold: 5 ug/g is considered the threshold for the health and reproductive success of freshwater fish (Lemly 1995)
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Did not observe deformities in larval fish Low survival possibly due to temperature and ammonia levels
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No observations of deformaties Mined areas had higher selenium levels in the following categories: Water selenium concentrations Benthic macroinvertebrates Whole body/gonad/egg concentrations
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