Transcript Document

Water Quality
Assessment of the
Brandywine Creek
Marilyn Murphy, David Plavcan, William
Shepard, Donna Suevo, Jeff Thomas, Karen
Trozzo, Timothy Woods and David Yezuita
West Chester University
July 2002
Introduction
• Water quality assessment of the
Brandywine Creek drainage basin.
• More emphasis on the East Branch.
• Samples collected at various points
including tributaries and downstream of
point sources.
• Impact of nutrients (nitrates and
phosphates) and coliforms evaluated.
• Recommendations and conclusions.
Purpose of Study
• Assess water quality in the Brandywine
Creek drainage basin.
• Determine impacts from point and non-point
sources of pollution.
• Provide recommendations to minimize
impacts.
Brandywine Creek Drainage
Basin Study Area
History of Water Quality in
Brandywine Creek
• Agricultural use created
problems with bacteria,
nutrients and sedimentation.
• Industrial use created
issues with synthetic/volatile
organic chemicals and
metals.
• Clean Water Act of 1972
enabled communities to
improve water quality.
Current Water Quality Issues
of the Brandywine Creek
• Increased residential
and commercial
growth.
• Increased storm water
runoff, loss of pervious
ground cover.
• Increased demand for
clean water.
Current Water Quality Issues
of the Brandywine Creek
• Watershed issues
encompass many
political borders.
• Cooperation and
coordination is a
challenge.
Sources of Discharge
• Two types of discharge:
 Point Source
• easily identifiable
• indicated by pipes, drainage ditches, channels,
tunnels, etc.
 Non-Point Source
• less obvious than point sources
• surface run-off most common but also includes
groundwater infiltration, erosion, and atmospheric
deposition
Point Sources to the East
Branch
• Downingtown Area Regional Wastewater
Treatment Authority (DARWTA)
• Taylor Run Sewage Treatment Plant
(TRSTP)
• Generic example:
Photo obtained from Freefoto.com,
accessed 7/13/02.
Potential Non-Point Sources to
the East Branch
• Run-off from agricultural fields, construction and
industrial sites, public parks, and golf course.
• Groundwater infiltration from faulty septic systems.
• Erosion from mineral deposits (naturally occurring).
• Others…
Example of potential non-point source pollution
from farm in rural Chester County.
Water Quality Concerns
• Drinking water
 Disinfection by products
 Pathogens (e.g., Giardia and Cryptosporidium)
 Terrorism
• Stream water
 Nutrients
 Industrial discharges
 Organic matter/DO level
Methods & Materials
Sample Collection
• Field observations included:
 types of vegetation
 substrate
 land use
• Grab samples obtained
using Horizontal Water
Sampler.
• Samples analyzed for nitrates,
phosphates and total
coliforms.
Methods & Materials
Dissolved Oxygen Concentrations
• Field measurements
included:
 DO
 pH levels
 conductivity
• DO meters measure the
oxygen content in the water.
• Low DO concentrations
negatively affects aquatic
life.
Methods & Materials
Conductivity & pH Levels
• Conductivity meters
• Salt/ion concentration
• Indicator of total dissolved solids (TDS)
• pH meters
 Availability of hydrogen ions
 Acceptable pH levels range
from 5-9 with adverse
biological effects occurring
outside of this range
Methods & Materials
Nitrate & Phosphate Analysis
• Laboratory analysis included estimating
concentration of nitrates, phosphates and
total coliforms.
• Nitrate and phosphate
concentrations were
determined by the standard
curves resulting from serial
dilutions of known
concentrations.
Methods & Materials
Nitrate & Phosphate Analysis
• Ultraviolet spectrometers were used to
measure absorbance values, which
reflect concentration levels in a sample.
• Analysis of the standards
produced a linear equation:
(y = mx + b).
• Analysis of the water samples
produced absorbance values
that were converted to nitrate
or phosphate concentrations
by linear equation.
Methods & Materials
Total Coliform Analysis
• Analysis of total coliforms
used a membrane filtration
technique.
• Water samples were passed
through 45-micron filters to
collect possible bacteria.
• Filters were placed in sterile
petri dishes and incubated for
24 hours at 35°C at which
time bacterial colonies were
counted.
15
10
*
5
Dissolved Oxygen (mg/L)
Dissolved Oxygen Results
0
19
18
17
16
15
14
13
12
11
n
St at io
n
St at io
n
St at io
n
St at io
n
St at io
n
St at io
2
3
4
5
6
7
8
9
10
n
St at io
1
* Current water quality standard concentration
n
St at io
n
St at io
n
St at io
n
St at io
n
St at io
n
St at io
n
St at io
n
St at io
n
St at io
n
St at io
n
St at io
n
St at io
Sampling Location
Dissolved Oxygen Results
by Sampling Location
Dissolved
Oxygen
12.9 – 11.0 mg/L
10.9 – 9.0 mg/L
8.9 – 7.0 mg/L
6.9 – 5.0 mg/L
800
700
600
500
400
300
200
100
0
Specific Conductivity
(microS/cm)
Specific Conductance Results
n 19
Statio
n 18
Statio
n 17
Statio
n 16
Statio
n 15
Statio
n 14
Statio
n 13
Statio
n 12
Statio
n 11
Statio
n 10
Statio
n9
Statio
n8
Statio
n7
Statio
n6
Statio
n5
Statio
n4
Statio
n3
Statio
n2
Statio
n1
Statio
Sampling Location
Specific Conductance Results
by Sampling Location
Conductivity
(microSeimens/cm)
600 - <700
599 - 500
499 - 400
399 - 300
299 – >200
Acceptable range of pH: 5-9
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
pH
pH Results
n 19
Statio
n 18
Statio
n 17
Statio
n 16
Statio
n 15
Statio
n 14
Statio
n 13
Statio
n 12
Statio
n 11
Statio
n 10
Statio
n9
Statio
n8
Statio
n7
Statio
n6
Statio
n5
Statio
n4
Statio
n3
Statio
n2
Statio
n1
Statio
Sampling Location
pH Results by Sampling Location
pH
9.4 –9.0
8.9 – 8.5
8.4 – 8.0
7.9 – 7.5
7.4 – 7.0
Water quality criteria value (10 mg/L)
*
*
*
*
12
11
10
9
8
7
6
5
4
3
2
1
0
-2
mg/L [NO3 -N]
Nitrate (NO3-2-N) Results
io n
io n
io n
io n
io n
1
2
3
4
9
n1
tio
8
Sta
n1
tio
7
Sta
n1
tio
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Sta
n1
tio
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Sta
n1
tio
4
Sta
n1
tio
3
Sta
n1
tio
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Sta
n1
tio
1
Sta
n1
tio
0
Sta
n1
tio
Sta
n9
tio
Sta
n8
tio
Sta
n7
tio
Sta
n6
tio
Sta
5
t
Sta
t
Sta
t
Sta
t
Sta
t
Sta
Sampling Location
* Downstream of WWTP effluent
Nitrate (NO3-2-N) Results
by Sampling Location
Nitrate-N
Concentrations
8.4 – 7.0 mg/L
6.9 – 5.5 mg/L
5.4 – 4.0 mg/L
3.9 – 2.5 mg/L
2.4 – 1.0 mg/L
Nitrate Historical Trends
July 2002 Result
Historical Median
4
-2
mg/L [NO3 -N]
5
3
2
1
0
Ford
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aset
Waw
wn
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Nitrate Discussion
• Downstream of point sources (WWTPs) typically
have greater levels of NO3-2-N.
• No samples exceed water quality criteria value
(10 mg/L).
• Current sample results fairly similar to historical
median concentrations.
• WWTPs are main entry point for nitrate in the
drainage basin.
• Decreased as distance from source increased.
*
EPA recommended value (0.1 mg/L)
9
n1
tio
8
Sta
n1
tio
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Sta
n1
tio
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Sta
n1
tio
5
Sta
n1
tio 4
Sta
1
n
tio
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Sta
n1
tio
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Sta
n1
tio
1
Sta
n1
tio
0
Sta
n1
tio
Sta
n9
tio
Sta
n8
tio
Sta
n7
tio
Sta
n6
tio
Sta n 5
tio
Sta
n4
tio
Sta
n3
tio
Sta
n2
tio
Sta
n1
tio
Sta
* Downstream of WWTP effluent
*
*
*
*
0.20
0.18
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00
-3
mg/L [PO4 -P]
Phosphate (PO4-3-P) Results
Sampling Location
Phosphate (PO4-3-P) Results
by Sampling Location
Phosphate-P
Concentrations
0.149 – 0.12 mg/L
0.119 – 0.09 mg/L
0.089 – 0.06 mg/L
0.059 – 0.03 mg/L
0.029 – 0.00 mg/L
-0.009 – 0.03 mg/L
mg/L [PO4-3-P]
Phosphate Historical Trends
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00
July 2002 Result
Historical Median
EPA recommended value (0.1 mg/L)
ND
ND
W ilm
on
ingt
et
own
ingt
own
own
ingt
own
d
For
dds
Cha
was
Wa
wD
Belo
ve D
Abo
ND = not detected
Phosphate Discussion
• Downstream of point sources (WWTPs) have
detected levels of PO4-3-P.
• One sample result exceeds EPA’s recommended
phosphate value (0.1 mg/L).
• Sample results slightly less than historical median
concentrations.
• WWTPs are main entry point for phosphate in the
drainage basin.
• Monitoring of effluent and more effective
treatment methods needed.
Total Coliform Results
(colonies/100 ml)
Total Coliform Colonies per 100 ml
500
1300
800
Upstream of Downingtown
Downstream of Downingtown
Upstream of Taylor Run
Downstream of Taylor Run
1200
1900
Delaware AREC Pond
Total Coliform Discussion
• Unhealthy bacteria levels prior to 1972 CWA.
• Bacteria concentrations decreased from
1973 – 1999 due to improved treatment and
decreased point source discharges.
• Fecal coliform bacteria limits (PADEP):
 200 colonies/100 mL from May-September
 2000 colonies/100 mL for rest of year
• Chlorination of water prior to discharge
eliminates much of the coliforms.
Conclusions
• Nitrate concentrations increased with
addition of points sources but remained
within the acceptable range.
• Coliforms effectively removed during
treatment process.
• Phosphate concentrations increased with
addition of points sources.
• pH and DO values were within acceptable
ranges.
Recommendations
• Measures to reduce pollution:




Riparian corridors
Stream bank fencing
Proper fertilizer application
Farming practices
• Phosphate removal
 More effective or better applied treatment of
phosphate
 Addition of aluminum sulfate
 Monitoring
Acknowledgements
• Gary Kreamer (Delaware Aquatic Resource
Education Center)
• Francis Menton (City of Wilmington Water
Department)