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Portland Water Bureau

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GENERAL INFORMATION: 503-823-7404

MAILING ADDRESS: 1120 SW Fifth Ave, Suite 600, Portland, OR 97204

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Cryptosporidium Treatment Variance Monitoring Results

As required by the treatment variance for Cryptosporidium, the Portland Water Bureau has been monitoring for Cryptosporidium in the Bull Run since April 2012.

Below is a summary of these results from the source water intake. Detailed reports from the past 12 months can be found here.

Bull Run Intake Cryptosporidium monitoring results.

From April 2012 through December 2016, a total of 1,149 samples for a total of 26,159L (6,910 gallons) were tested with no detections for Cryptosporidium.

April 2012 through December 2016

Number of Samples

Positive Samples

Volume Sampled

1,149

0

26,159L (6,910 gals)

From January to March 2017, a series of low levels of Cryptosporidium (19 oocysts in 14 samples) were detected from the Bull Run drinking water intake. From September to November, 2017 additional samples have also been positive for Cryptosporidium.

2017 Results through November 8, 2017 (updated 11/9/2017)

Number of Samples

Positive Samples

Volume Sampled

Oocysts detected

349

27

10,061.25L (2,658 gals)

34

 

Information on the positive samples from 2017 are below:

Date of positive   sample

Sample   Volume

(Approx.)

No. of   Oocysts

Detected

Observation Monitoring

Jan. 2, 2017

50L (13 gals)

2

Jan. 3, 2017

50L (13 gals)

3

Demonstration Monitoring

Jan. 25, 2017

50L (13 gals)

1

Feb. 1, 2017

50L (13 gals)

1

Feb. 7, 2017

50L (13 gals)

1

Feb. 8, 2017

50L (13 gals)

2

Feb. 13, 2017

50L (13 gals)

1

Feb. 14, 2017*

50L (13 gals)

1

Feb. 15, 2017*

50L (13 gals)

1

Feb. 21, 2017*

50L (13 gals)

2

Feb. 22, 2017*

 50L (13 gals)

1

Feb. 26, 2017*

 50L (13 gals)

1

Mar. 8, 2017*

 50L (13 gals)

1

Mar. 12, 2017*

 50L (13 gals)

 Sept. 24, 2017

 10L (2.6 gals)

 1

 Sept. 27, 2017

 10L (2.6 gals)

 1

  Oct. 18, 2017

 10L (2.6 gals)

 1

 Oct. 22, 2017

 10L (2.6 gals)

 Oct. 22, 2017

 10L (2.6 gals)

 2

 Oct. 24, 2017

 10L (2.6 gals)

1

Oct. 24, 2017

10L (2.6 gals)

1

Oct. 29, 2017

10L (2.6 gals)

1

 Oct. 29, 2017

 10L (2.6 gals)

 1

 Nov. 5, 2017

10L (2.6 gals)

 2

 Nov. 6, 2017

10L (2.6 gals)

 1

 Nov. 7, 2017

10L (2.6 gals)

 1

 Nov. 8, 2017

10L (2.6 gals)

* Results do not represent water served to customers. From February 13 to March 15, Portland was using the Columbia South Shore Well Field as its drinking water source.

Observation Monitoring: Routine monitoring for Cryptosporidium at the Bull Run intake at least two days each week and each day when the turbidity is greater than 2.0 NTU.

Demonstration Monitoring: If Cryptosporidium is detected under observation monitoring, within one week the Portland Water Bureau must increase monitoring for Cryptosporidium to at least four days per week.