Transcript Slide 1
Selenium
› Naturally occurring metalloid
› Associated with:
Coal seams
Phosphate deposits
Other mineral formations
Increased
mobilization due
to:
› Irrigation
› Sewage
› Fly ash/coal
combustion
› Mining
4
Oxidation states
› Selenite (SeO3 -2)
› Selenate (SeO4 -2)
› Selenides (Se -2)
› Elemental selenium (Se)
Insoluble
Poorly assimilated by aquatic
plants
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
Benefits:
› Protects DNA, lipids, and proteins
If fish are deficient:
› Loss coordination
› Reduced growth
› Reduced immune response
Impairs
gas exchange
› Swollen lamellae
Constricts blood vessels
› Binds to hemoglobin
Unable to carry oxygen
Induce
cataracts
Edema
Seleno-proteins
Similar
to sulfides
Cells cannot discriminate
Selenium substituted for sulfur
Results in dysfunctional amino
acids/proteins
Accumulates in gonads, kidney,
and liver
Seleno-proteins
stored in ovarian
tissues
Proteins transferred to eggs
› Building blocks for tissue synthesis
› Metabolic fuel
External
feeding
› Critical period
› High mortality
Faulty
proteins used for
development
Results in teratogenesis:
› Craniofacial deformities
› Spinal deformities
› Missing fins
› Edema
Inability
to feed leading to death
Kyphosis
Lordosis
Scoliosis
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
1)
Lower
Guyandotte River
Watershed
Lincoln and Boone Counties, WV
124 ha reservoir
4.5-6 m depth
Inhabitants:
› Bluegill
› Largemouth bass
› Crappie
› Channel catfish
Paint
Creek Watershed
Fayette County, WV
81.75 ha reservoir
12.2 m depth
Inhabitants:
› Bluegill
› Largemouth bass
› Channel catfish
› White crappie
October
2008-November 2010
Mud River (main stem and
tributaries)
› 20 total sites
› Mined (13)
› Unmined (7)
Reference
› 2 sites
Site
Water quality
Plum Orchard Lake
(Reference Site)
YSI:
DO, pH,
temperature,
conductivity
Total and
dissolved Fe, total
Se, TDS, sulfates,
alkalinity,
hardness, TSS and
TOC
Picture credit: Melissa O’Neal
July
2009
Stantec, Inc.
Stream (13)
Reservoir (5)
› Transects
› Top 5 cm
Picture credit: Stantec, Inc., Lexington, KY
July,
August,
September 2010
Mud River
Reservoir (2)
Reference Site (1)
10-20 min/ tow
Surface and mid
depth
95% ethanol
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 O’Neal
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
June 2009 and 2010
2009: Entire redd
collected
2010: Only shells,
rocks, and
branches
Individual redds
collected
Transported to
WVU wet lab
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
Multiple
full
water changes
done daily
Ammonia (daily)
Nitrite,
alkalinity,
hardness
(weekly)
Temperature,
DO, and pH
(subset daily)
Variable
Temperature (oC)
Conductivity
(µs/cm)
pH
DO (mg/L)
Mined
14.19 ± 0.42a
Unmined
Reference
13.60 ± 0.57a 17.83 ± 1.45b
1059.93 ± 33.91a 152.23 ± 7.16b 38.38 ± 0.66c
7.77 ± 0.02a
7.26 ± 0.05b
7.05 ± 0.09b
8.91 ± 0.32a
8.23 ± 0.20a
9.63 ± 1.88a
Hardness (mg/L
CaCO3)
640.81 ± 31.91a 60.14 ± 5.49b 13.35 ± 0.302c
Alkalinity (mg/L
CaCO3)
159.45 ± 5.54a
37.09 ± 2.05b 16.87 ± 1.37c
Variable
TDS (mg/L)
Mined
Unmined
Reference
1416.57 ± 217.61a 139.16 ± 16.52b 16.87 ± 1.37c
Sulfate (mg/L)
462.24 ± 17.11a
39.87 ± 8.64b
12.14 ± 0.64c
Dissolved Iron
(mg/L)
0.068 ± 0.007a
0.131 ± 0.009b 0.208 ± 0.023c
Total Iron
(mg/L)
0.606 ± 0.189a
0.566 ± 0.093ab 0.336 ± 0.037b
Total Selenium
(µg/L)
6.52 ± 0.289a
0.262 ± 0.015b 0.194 ± 0.021b
TOC (mg/L)
3.46 ± 0.36a
3.22 ± 0.308a
3.15 ± 0.079a
1.4
1.2
Selenium (µg/g DW)
1.0
aa
0.8
0.6
0.4
a
a
0.2
0.0
Mined
Unmined
Site Type
Selenium (µg/g DW)
4
a
3
2
a
1
a
a
a
0
MudR16 MudR17 MudR18 MudR19 MudR14
Reservoir Transect
18
Selenium (µg/g DW)
16
14
a
12
a
10
8
6
4
b
2
0
Mined
Unmined
Site Type
Reference
Site
Filterer
Gatherer
Scraper
Shredder
Composite
Unmined 2.69 ± 0.4a 3.90 ± 1.0a 3.7 ± 0.52a 1.9 ± 0.72a 3.4 ± 0.42a
Mined
Reference
11.7 ± 1.4b 12.44 ± 1.8b 8.1 ± 0.93b 11.5 ± 2.45b 11.1 ± 0.87b
N/A
2.67 ± 0.04a
N/A
0.88 ± 0.12a 2.1 ± 0.50a
0
5
10
15
20
25
Selenium (µg/g DW)
30
35
*
a
b
Mud Reservoir
Reference
Site
0
5
10
15
20
25
Selenium (µg/g DW)
30
*
a
b
Mud Reservoir
Reference
Site
Variable
Temperature (oC)
Dissolved O2 (mg/L)
pH
Reference
Mud River
Reservoir
21.41 ± 0.12*
22.69 ± 0.12
7.87 ± 0.09
7.99 ± 0.05
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
20 ± 0.0*
250 ± 0.0
16.35 ± 1.13*
80 ± 0.0
Hardness (mg/L CaCO3)
Alkalinity (mg/L CaCO3)
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
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
Mud
River Reservoir (mined
and unmined) sites differed
from the reference site
Not sorted to species
(zooplankton, etc.)
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
No
hazard category for whole
body/gonad selenium
concentrations
Egg selenium (68.76 ± 1.95 µg/g )
High hazard (>20 µg/g)
10
20
30
Reference
Mud Reservoir
Toxic Effect Threshold
0
Selenium (µg/g DW)
5 ug/g is
considered the
threshold for
the health and
reproductive
success of
freshwater fish
(Lemly 1995)
40
Toxic Effect
Threshold:
20
40
60
Weight (g)
80
100
Did
not observe deformities in
larval fish
Low survival possibly due to
temperature and ammonia
levels
No
observations of deformaties
Mined areas had higher
selenium levels in the following
categories:
› Water selenium concentrations
› Benthic macroinvertebrates
› Whole body/gonad/egg concentrations