Abstract ........................................................ 1
Introduction .................................................... 2
Mercury Cycling in Aquatic Ecosystems ........................ 2
Health Effects, Criteria, and Advisories for Mercury ......... 4
Description of the Study Area ................................ 5
Purpose and Scope ............................................ 5
Methods of Study ................................................ 6
Sources of Data .............................................. 6
Organization of Data ........................................ 14
Mercury Load Calculations ................................... 14
Mercury in Indiana Watersheds .................................. 19
Mercury in Streams .......................................... 19
Mercury in Fish ............................................. 36
Sources of Mercury .......................................... 41
Atmospheric Mercury Deposition ........................... 41
Mercury Emissions to the Atmosphere ...................... 47
Mercury in Wastewater .................................... 50
Land Cover ............................................... 53
Summary and Conclusions ........................................ 60
References ..................................................... 62
Appendix 1. Supplemental Data .................................. 67
Figures
1. Diagram showing the mercury cycle in aquatic ecosystems ... 3
2-4. Maps showing:
2. Indiana monitoring stations for mercury in streams,
with upstream watershed boundaries, monitoring stations
for mercury in precipitation, and sampling locations
for mercury in fish tissue ................................ 7
3. National Atmospheric Deposition Program Mercury
Deposition Network stations used to compute average
annual total mercury concentrations in precipitation in
Indiana, and National Weather Service Cooperative
Observer Network sites used to compute average annual
precipitation in Indiana, 2001-2006 ....................... 9
4. Treatment works in Indiana with total mercury analyses
of wastewater-effluent samples, 2002-2005; upstream
watershed boundaries are shown for monitoring stations
on streams ............................................... 10
5. Graph showing annual emissions of mercury to the
atmosphere from all categories of sources in Indiana in
2002 and 2005 ............................................ 11
6-7. Maps showing:
6. Stationary sources of mercury emissions to the
atmosphere in Indiana in 2002 and 2005; upstream
watershed boundaries are shown for monitoring stations
on streams ............................................... 12
7. Permitted wastewater outfalls in Indiana in 2005;
upstream watershed boundaries are shown for monitoring
stations on streams ...................................... 13
8. Box plots showing distributions of unfiltered total
mercury concentrations in water samples at monitoring
stations on Indiana streams, 2002-2006 ................... 21
9. Graph showing average percentages of filtered and
particulate total mercury in water samples at
monitoring stations on Indiana streams, 2002-2006 ........ 24
10. Graph and box plots showing relations of particulate
total mercury concentrations in water samples to
turbidity values and ranges of turbidity in water at
the time of sample collection at monitoring stations on
Indiana streams, 2002-2006 ............................... 26
11. Box plots showing distributions of unfiltered and
filtered total mercury concentrations in water samples
at monitoring stations on Indiana streams, grouped by
daily mean streamflow category for instantaneous
streamflow at time of sample collection, 2002-2006 ....... 30
12. Map showing average annual stream yields of total
mercury in watersheds upstream from monitoring stations
on Indiana streams, 2002-2006 ............................ 32
13. Box plots showing distributions of wet-weight and dry-
weight mercury concentrations in fish-tissue samples
from watersheds in Indiana, 1993-2004 .................... 37
14. Isopleth map of average annual mercury wet-deposition
rates, 2001-2006, showing upstream watershed boundaries
for monitoring stations on Indiana streams ............... 42
15-17 Maps showing:
15. Ratios of average annual stream mercury yield to
atmospheric mercury wet-deposition loading in
watersheds upstream from monitoring stations on Indiana
streams, 2001-2006 ....................................... 46
16. Treatment works upstream from monitoring stations on
Indiana streams, with average total mercury
concentrations in samples of wastewater effluent, 2002-
2005 ..................................................... 51
17. Land-cover types in watersheds upstream from monitoring
stations on Indiana streams .............................. 59
Tables
1. Monitoring stations on Indiana streams, 2002-2006, and
upstream drainage areas .................................. 16
2. Summary statistics for mercury concentrations in water
samples from monitoring stations on Indiana streams,
2002-2006 ................................................ 20
3. Total mercury concentrations in water samples from
monitoring stations on Indiana streams, 2002-2006, with
comparisons to Indiana water-quality criteria ............ 22
4. Filtered total mercury and estimated particulate
mercury concentrations in water samples from monitoring
stations on Indiana streams, 2002-2006 ................... 25
5. Unfiltered methylmercury concentrations in water
samples at monitoring stations on Indiana streams,
2002-2006 ................................................ 28
6. Seasonal Kendall test for trends in unfiltered total
mercury concentrations in water samples from monitoring
stations on Indiana streams, 2002-2006 ................... 29
7. Average annual stream loads and yields of unfiltered
total mercury and unfiltered methylmercury in
watersheds upstream from monitoring stations on Indiana
streams, 2002-2006 ....................................... 34
8. Mercury concentrations in fish-tissue samples from
watersheds upstream from monitoring stations on Indiana
streams, 1993-2004 ....................................... 38
9. Mercury concentrations in fish-tissue samples near
monitoring stations on Indiana streams, 1993-2004 ........ 40
10. Average annual atmospheric mercury wet-deposition loads
and loading rates, 2001-2006, and average annual stream
yields of total mercury, 2002-2006, in watersheds
upstream from monitoring stations on Indiana streams ..... 44
11. Atmospheric mercury species concentrations, vertical
deposition velocities, and annual dry-deposition rates
in Indiana, 2004 ......................................... 45
12. Annual atmospheric mercury dry-deposition and wet-
deposition loading rates and annual stream yields of
total mercury in watersheds upstream from monitoring
stations on Indiana streams .............................. 48
13. Average total mercury concentrations in grab samples of
wastewater effluent at treatment works upstream from
monitoring stations on Indiana streams, 2002-2005 ........ 52
14. Number of permitted outfalls in 2005 for watersheds
upstream from monitoring stations on Indiana streams ..... 54
15. Land-cover types, by percentage of watershed drainage
area and land area in watersheds upstream from
monitoring stations on Indiana streams ................... 56
16. Watersheds upstream from monitoring stations on Indiana
streams, grouped by upstream drainage-area size .......... 58
Appendix 1 Tables
1-1. Correlations of mercury concentrations with
instantaneous streamflow at monitoring stations on
Indiana streams, 2002-2006 .............................. 68
1-2. Statistical values separating categories of daily
average streamflow at monitoring stations on Indiana
streams, 2002-2006 ...................................... 69
1-3. Annual stream loads and yields of unfiltered total
mercury and unfiltered methylmercury in watersheds
upstream from monitoring stations on Indiana streams,
2002-2006 ............................................... 70
1-4. Model characteristics of annual stream loads of
mercury in watersheds up stream from monitoring
stations on Indiana streams, 2002-2006 .................. 75
1-5. Number of stationary sources of mercury emissions to
the atmosphere and annual mercury emissions in 2002
and 2005 for watersheds upstream from monitoring
stations on Indiana streams ............................. 76
1-6. Percentages of land-cover classes in watersheds
upstream from monitoring stations on Indiana streams .... 77
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