BACTERIA LEVELS IN THE ILLINOIS RIVER
R. B. Needham, PhD
9/25/05
SUMMARY
The purpose of this study is to determine the levels of bacteria in the Illinois River and
judge the indicated health hazards to recreational users of the river. The most extensive
data set for the indicator bacteria--fecal coliform, E. coli, and fecal streptococci--has been
collected by the USGS over the years from about 1996 to 2004 at the monitoring stations
near Watts, Chewey and Tahlequah, starting near the Arkansas and Oklahoma state line
and moving to near Lake Tenkiller. The water quality conditions with respect to nutrients
and bacteria are essentially established upstream of the Watts station and continue on
downstream. The concentration of the nutrients total phosphorus and nitrates are highest
at Watts and decline with distance downstream from Watts to Tahlequah.
All of the USGS data from these three stations show high levels of the indicator bacteria.
In particular the indicator bacteria fecal strep is above the standard of 33 cfu/100ml most
of the time. The frequency of the collection of the USGS samples does not meet the
requirements of the guidelines of the USEPA, but the levels of bacteria measured shows
that the guidelines for fecal strep would very likely be violated if the more frequent
sampling were performed. The USGS sampling is taken nominally every month and the
guidelines call for a minimum of five samples to be taken within 30 days and then the
geometric mean of the population must be above 33cfu/100ml to be considered unsafe.
The unsafe condition is from the point of view of the probability of the recreational user
contacting a related disease more than 8 times for each 1000 exposures. (A. P. Dufour--
EPA-600/1-84-004)
The characteristics of the water quality with respect to nutrients and bacteria suggest that
a significant part of the source of the bacteria is non-point. The concentrations of total
phosphorus and bacteria increase dramatically as the stream flow rate increases at each
monitoring station. In contrast there is no simular correlation with nitrates.
Based on the information in this study, it is recommended that a protocol be established
to monitor the bacteria levels at the state line and the significant downstream recreational
locations on the Illinois River. The protocol should meet the guidelines for monitoring of
indicator bacteria as set out in the USEPA guidelines.
TIME CHARTS FOR THE INDICATOR BACTERIA
Watts Monitoring Station--
The measured levels of the indicator bacteria from water samples taken monthly are
plotted on charts for the time period of 1996 to 2003. Measurements were not taken in
2004. Figures 1, 2 and 3 show the data for fecal coliform, E. coli and fecal strep,
respectively. Table 1 summarizes the portion of the samples that were below the
1
respective standard for the individual indicator bacteria. Several facts are evident from
the data:
Taking the indicator bacteria data as a whole, it is evident that bacteria levels are
likely at unsafe levels over the major portion of the time throughout the year.
It is more likely that the bacteria are above safe levels during the summer months.
Bacteria levels have increased dramatically from the 1996-98 time period to the 2000-
2003 time period. Figure 4 shows the geometric mean for each of the time periods
and indicates the dramatic increase in the bacteria levels.
There is an urgent need to measure the bacteria levels following the USEPA
guidelines to establish "officially" the unsafe levels of the indicator bacteria.
The adoption of fecal strep as the indicator bacteria of choice would provide a safer
measure of the health hazard to recreational users of the river.
Chewey Monitoring Station--
The pattern for indicator bacteria for the Chewey station is similar to Watts, except no
data were reported for E. coli in the pre-1999 time period. Figures 5, 6 and 7 show the
data for fecal coliform, E. coli and fecal strep, respectively. Table 2 summarizes the
portion of the samples that are below the standards.
Tahelquah Monitoring Station--
Again the general pattern of the indicator bacteria for the Tahlequah station is similar to
Watts. Figures 8, 9 and 10 show the data for fecal coliform, E. coli and fecal strep,
respectively. Table 3 summarizes the portion of the samples where the levels of bacteria
are below the standard values. As at the other stations, fecal strep is at levels above the
standard value of 33cfu/100ml more frequently than is either fecal coliform or E. coli.
Figure 11 shows a graph for the station at Tahlequah that is similar to Figure 4 for the
station at Watts. The levels of bacteria for the time period of 2000-2003 are much higher
than for the time period 1996-98. The increase in the bacteria levels is much higher for
the Watts station than for the Tahlequah station.
CORRELATIONS OF SELECTED WATER QUALITY PARAMETERS
Selected correlation of total phosphorus, nitrates, stream flow rates and indicator bacteria
levels can offer insights into the nature and source of the pollution of the Illinois River.
Watts Monitoring Station--
Figure 12 shows the increase in the concentration of total phosphorus that accompanies
the increased in the stream flow rate. Such behavior is a strong indicator that a significant
part of the phosphorus loading is caused by non-point sources. In addition, Figure 13
shows that all three of the indicator bacteria increase with increased flow rate. This is a
good indication that the non-point sources of the total phosphorus and bacteria may be
linked. In contrast, the concentrations of nitrate+nitrite do not show the same pattern of
increase with the increase in stream flow rate (Figure 14). This pattern would be
consistent with runoff from areas where poultry litter had been historically applied using
nitrogen needs as the guideline for application. Figures 15 and 16 show the time variation
in total phosphorus and nitrate+nitrite.
2
Tahelquah Monitoring Station--
Figures 17-21 are the similar plots for the Tahlequah monitoring station. By comparing
the correlations, it is clear that the water quality pattern in the Illinois River at Tahlequah
is the pattern established at the monitoring station at Watts. The watershed practices
upstream of Watts dominate the water quality condition of the River.
I have not included the similar data for the Chewey monitoring station, however they
show the same pattern.
Direct comparison of selected parameters at Watts with Tahlequah--
The loading of total phosphorus in the Illinois River is dominated by the loading from
upstream of Watts. Figure 22 shows a plot of the calculated loading using the measured
concentration of total phosphorus and the instantaneous flow rate measured when the
water samples were taken. The sampling procedure was changed in 1999 to target getting
data for the high flow events and that change is evident on the plot. In some instances the
storm events caused as many as three samples to be taken and reported within a given
month. Figure 23 shows the nutrient levels at Watts compared to Tahlequah. The time
period taken for the calculation of the median concentration was from 2000 through
2004.
Figure 24 is a plot of the geometric mean for each of the indicator bacteria for the time
period 2000-2003 for Watts compared to the data collected at Tahlequah.
These figures taken together show very clearly that the source of the total phosphorus and
indicator bacteria are the result of practices in the Illinois Watershed upstream of Watts.
TABLE I
ILLINOIS RIVER AT WATTS
USGS 07195500
Data taken 1996-2004
Indicator Total number Number with cfu/100ml Portion of samples
Bacteria of samples less than standard Below standard,
%
Fecal Coliform 58 31 53
E. Coli 39 17 44
Fecal Strep 59 4 6.8
3
TABLE II
ILLINOIS RIVER AT CHEWEY
USGS 07196090
Data taken 1996-2004
Indicator Total number Number with cfu/100ml Portion of samples
Bacteria of samples less than standard Below standard,
%
Fecal Coliform 50 26 52
E. Coli 25 5 20
Fecal Strep 57 4 7.0
TABLE III
ILLINOIS RIVER NEAR TAHLEQUAH
USGS 07196500
Data taken 1996-2004
Indicator Total number Number with cfu/100ml Portion of samples
Bacteria of samples less than standard Below standard,
%
Fecal Coliform 51 30 59
E. Coli 39 17 44
Fecal Strep 61 3 4.9
4
Figure 1
Illinois River near Watts--USGS 07195500
100000
Fecal coliform
Fecal Coliform standard = 200 cfu/100ml
10000 53 % of the samples
were below the standard
Fecal Coliform, cfu/100ml
1000 Fecal Coliform standard
100
10
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04
5
Figure 2
Illinois River near Watts--USGS 07195500
100000
E. coli
E. Coli standard = 126 cfu/100ml
10000 43 % of the samples
were below the standard
E. Coli, cfu/100ml
1000
E. Coli standard
100
10
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04
6
Figure 3
Illinois River near Watts--USGS 07195500
100000
Fecal strep
Fecal Strep standard = 33 cfu/100ml
6.8 % of the samples are
10000 below the standard
Fecal Strep, cfu/100ml
Fecal Strep standard
1000
100
10
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04
7
Figure 4
Illinois River near Watts--USGS 07195500
10000
1996-98
2000-2003
Geometric Mean for indicated time period
1656
1171 1174
1000
121
100
49
28
10
Fecal Coliform E. Coli Fecal Strep
8
Figure 5
Illinois River at Chewey--USGS 07196090
100000
Fecal Coliform
Fecal Coliform standard = 200 cfu/100ml
52 % of the samples
10000 were below the standard
Fecal Coliform, cfu/100ml
Fecal Coliform standard
1000
100
10
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04
9
Figure 6
100000
Illinois River at Chewey--USGS 07196090
E. Coli
E. Coli standard = 126 cfu/100ml
20 % of the samples
10000 were below the standard
E. Coli, cfu/100ml
1000 E. Coli standard
100
10
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04
10
Figure 7
Illinois River at Chewey--USGS 07196090
100000
Fecal Strep
Fecal Strep standard = 33
cfu/100ml
10000 7.0 % of the samples
were below the standard
Fecal Strep, cfu/100ml
Fecal Strep standard
1000
100
10
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04
11
Figure 8
Illinois River near Tahlequah--USGS 07196500
100000
Fecal coliform
Fecal Coliform standard = 200 cfu/100ml
59 % of the samples
10000
were below the standard
Fecal Coliform, cfu/100ml
Fecal Coliform standard
1000
100
10
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04
12
Figure 9
Illinois River near Tahlequah--USGS 07196500
100000
E. Coli
E. Coli standard = 126 cfu/100ml
44 % of the samples
10000 were below the standard
E. Coli, cfu/100ml
1000 E. Coli standard
100
10
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04
13
Figure 10
Illinois River near Tahlequah--USGS 07196500
100000
Fecal Strep
Fecal Strep standard = 33 cfu/100ml
4.9 % of the samples
10000
were below the standard
Fecal Strep, cfu/100ml
Fecal Strep standard
1000
100
10
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04
14
Figure 11 Illinois River near Tahlequah--USGS 07196500
Geometric Mean for indicator bacteria for time period indicated
10000
1996-98
2000-2003
924
1000
523 588
237
98
100
41
10
Fecal Coliform E. Coli Fecal Strep
15
Figure 12
Illinois River at Watts--USGS 07195500
10
Total Phosphorus
Median flow = 444 cfs
Linear (Total Phosphorus)
1
TP, mg/L
0.1
0.01
10 100 1000 10000 100000
flow rate, cfs
16
Figure 13
Illinois River at Watts--USGS 07195500
100000
Median flow = 444 cfs
Fecal Coliform
10000
Indicator bacteria, cfu/100ml
1000 E. Coli
100
Fecal Strep
10
10 100 1000 10000 100000
flow rate, cfs
17
Figure 14
Illinois River at Watts--USGS 07195500
4.5
nitrate+nitrite
4.0
3.5
nitrates+nitrites, mg/L
3.0
2.5
2.0
1.5
1.0
0.5
0.0
10 100 1000 10000 100000
flow rate, cfs
18
Figure 15
Illinois River at Watts--USGS 07195500
10
Total Phosphorus
1
Total Phosphorus, mg/L
0.1
0.01
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05
19
Figure 16
Illinois River at Watts--USGS 07195500
10
Nitrate plus nitrite, mg/L
1
Nitrate+nitrite
0.1
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05
20
Figure 17
Illinois River near Tahlequah--USGS 07196500
10
Total Phosphorus
Linear (Total Phosphorus)
Median flow = 785 cfs
Total Phosphorus, mg/L
1
0.1
0.01
10 100 1000 10000 100000
flow rate, cfs
21
Figure 18
Illinois River near Tahlequah--USGS 07196500
100000
Median flow = 785 cfs
Fecal coliform
10000
indicator bacteria, cfu/100ml
1000 E. Coli
100
Fecal Strep
10
10 100 1000 10000 100000
flow rate, cfs
22
Figure 19
Illinois River near Tahlequah--USGS 07196500
4.0
nitrate + nitrite
3.5
3.0
nitrate plus nitrite, mg/L
2.5
2.0
1.5
1.0
0.5
0.0
10 100 1000 10000 100000
flow rate, cfs
23
Figure 20 Illinois River near Tahlequah--USGS 07196500
10
Total Phosphorus
Total Phosphorus, mg/L
1
0.1
0.01
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05
24
Figure 21
Illinois River near Tahlequah--USGS 07196500
10
Nitrate plus nitrite, mg/L
1
0.1
Nitrate+nitrite
0.01
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05
25
Figure 22 Calculated loading of Total Phosphorus at Watts and Tahlequah
1000000
Illinois at Watts
Illinois at Tahlequah
100000
load of TP, #/day
10000
1000
100
10
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05
26
Figure 23 Nutrients in the Illinois River at Watts compared to Tahlequah
Median for all data taken during the time period 2000-2004
2.0
1.75 Watts Tahlequah
1.59
1.5
Median Concentration, mg/L
1.0
0.5
0.31
0.15
0.0
Nitrate + nitrite Total Phosphorus
27
Figure 24 Indicator Bacteria in the Illinois River at Watts compared to Tahlequah
Geometric Mean for samples taken during the time period 2000-2003
2000
Watts Tahlequah
1656
1500
Geometric Mean, cfu/100ml
1171 1174
1000 924
588
523
500
0
Fecal Coliform E. Coli Fecal Strep
28