Measuring Stream Microbiology:Preliminary Results

Dr. Robert D. SimonMr. Jacob D. AlmeidaMr. Jonah StevensDepartment of BiologySUNY-Geneseo

Microbial Quality is Monitored by Measuring

Surrogates• Coliforms• Fecal Coliforms• Escherichia coli

Fecal Streptococci• Enterococci

• Total Heterotrophic Bacteria

Coliforms

• Found in the gut and feces of warm-blooded animals

• Aerobic and facultative anaerobic, Gram-negative, non-spore forming rod shaped bacteria that ferment lactose with gas formation within 48 hours at 35 °C.

• Enterobacteriaceae• Membrane Filtration (MF) MF -

Dark colony with a metalic sheen on an “Endo” type medium.

Fecal Coliforms

• A subset of Total Coliforms• Fecal coliforms - Produce gas from

lactose at 44.5 °C. • Prior to its 1986, EPA recommended

the use of fecal coliforms as an indicator organism to protect bathers from gastrointestinal illness in recreational waters.

Membrane Filter methods for Total Coliforms and E. coli using Millipore

mColiBlue24

• Next day results• Easy to read with turbid samples• Clonal isolates can be saved for further study

Fecal Streptococcus• Isolated from the feces of warm-

blooded animals• A number of species of the genus

Streptococcus• It is not possible to differentiate the

source of fecal contamination based on speciation

• FC/FS ratio can also not be used as a means of differentiating human and animal feces

Enterococcus

• A subgroup of fecal streptococci, including:S. faecalis, S. faecium, S. gallinarum, S. avium

• Differentiated by ability to grow in 6.5% NaCl at 10 °C and 45 °C

• Difco m Enterococcus Agar

Heterotrophic Bacteria

• Bacto R2A Agar. A low-nutrient medium. Incubation at 25 °C for 40-72 hours, stimulates the growth of stressed and chlorine-tolerant bacteria

• Multiple 20 l drops of water dilutions are spotted on plates, and micro-colonies are counted under a dissecting microscope

EPA’s Recommended 1986 Water Quality Criteria for Bacteria in Recreational Fresh Water

IndicatorBacteria

Illness Rate(per 1000)

GeometricMean

DensityDesignatedBeach Area

InfrequentlyUsed Full Body

Contact

enterococci 8 33 62 151E. coli 8 126 235 576

• Based on the epidemiology of water-born disease occurrence as E. coli and Enterococci levels exhibit a strong correlation to swimming-associated gastroenteritis.

Results

Two Types of Stream Flow

• Regular Flow (Grab Samples)– Slow flow during the summer, a portion

probably from groundwater – It is surprising how much flow there is in

the Winter– Weekly measure stream characteristics

• Events– Due to rain or snow melt

Assessing Overall Stream Microbial Quality From Grab

Samples• Because of the variability in

individual measurements, it is valuable to to combine monthly regular (non-event) estimates.

• The geometric means of monthly samples are calculated because this damps out the effect of a few extreme values.

Sand Point

Graywood

Long Pt. Cove

Cottonwood Gully

McPhersons Point

Sutton Point

Long Point

Experimental sites with weed beds

Control sites with weed beds

Experimental site without weed beds

Control sites without weed beds

Southwest Creeks North

McMillan

Conclusions about Regular Flow

• E. coli and Enterococcus levels are seasonal

• Total Coliforms and Heterotrophic Bacteria vary little over the year.

• Graywood is the most regularly contaminated stream and on the western side of the lake the streams at the northern end have the most problems with water quality.

Events

• The Number and Characteristics, of Events vary by Season and Stream Source

Manure Spread on Snow Above Graywood -

February 2003

Events

• There are Different Types of Events

Turbidity

0.0

10.0

20.0

30.0

40.0

50.0

6/17 6/24 7/1 7/8 7/15 7/22 7/29 8/5 8/12 8/19 8/26 9/2

Date

NTU

Sutton Point – Two Recorded Events from 6/17/03 – 9/2/03

1 2

Given the Large Inputs into Streams During Events Do these Persist in the Stream or Lake?

• Sediment Microbiology• Analysis of Fecal Coliform Levels in

Sediments from the Stream and Lake Near the Stream Outfalls

• No Evidence for Significant Accumulations of Fecal Material in Sediments or Stream Bottoms

Major Conclusion

Future Plans

• Continue monitoring program• Use current data to better understand

the number, types and magnitude of different events. This may aid in monitoring clean-up as one might aim to prevent certain event types.

• Examine the changing character of the Heterotrophic bacterial flora

The End