The Question

Date: Thu, 18 Sep 2008 10:58:41 -0400
From: Gracia O'Neill <gracia@cwfnc.org>

Greetings,

Does anyone have any recommendations for an easy to use bacteria sampling protocol that could be used by trained volunteers?

We run an advanced volunteer benthic sampling program in western NC, that partners with a university-run chemical sampling program, which provides date directly to our state water quality agency. Therefore we are looking for an inexpensive and easy to use, yet accurate protocol. We have access to e-coli (not total coliform) incubators, but no other supplies at this time.

Are there any recommendations on whether to sample for e-coli vs. total coliform?

THANKS!

~Gracia

---------------------
Gracia O'Neill
Assistant Director
Clean Water for North Carolina
29 1/2 Page Ave.
Asheville, NC 28801
(828) 251-1291
www.cwfnc.org

Responses

Date: Fri, 19 Sep 2008 02:24:19 -0700 (PDT)
From: Kimberly Rinard <cooter1994@yahoo.com>

Gracia

Check out the 9223 Collilert Total Coliform methods. It requires minimum labor/training regarding staff as you collect your sample in a sterile 125ml bottle then add a packet. Mix the packet in the sample according to directions, then incubate for "x" hours(pretty sure it is 18hrs) The QT method is typically used for "raw" waters such as surface waters(lakes, streams, ponds etc) or untreated drinking water wells(pre chlorination) The QT method will also allow you to get a colony count.

The 9223_PA method is typically used for chlorinated waters(drinking water) where the only result needed is absence/presence . The PA method will also allow you to do E Coli on the same sample.

Any bacteria present in your sample will generate a gas thru a fermentation process as they react/consume the stuff in the packet that is added to the sample. Total Coliform Results are determined by the presence of a color change. The Collilert method will also allow you to do E Coli on the same sample as, a sample positive for E Coli will change color under UV light.

I know many town beaches/state programs require the 1103.1 Beach method for E Coli but I am not familiar with how it is run. The other methods out there are 9222B Membrane Filtration for Total Coliform, and 9222D Fecal Coliform, 9215(E?) Heterotrophic Plate Count

Pay careful attention to samples that are turbid/cloudy as this will affect the interpretation of the color change after incubation. Dilutions should be run whenever necessary, especially during times of high runoff, to avoid the "colonies too numerous too count" results.

Good luck and feel free to write back!

Kim Rinard
Granby, Mass

Date: Fri, 19 Sep 2008 08:41:24 -0400
From: Ann Reid <ann.reid@unh.edu>

Check the Volunteer Monitor issue on bacteria...http://www.epa.gov/volunteer/newsletter/volmon18no1.pdf

Date: Mon, 22 Sep 2008 13:58:08 -0400
From: Kirk Barrett <kirk.barrett@montclair.edu>

We use coliscan easygel (see www.micrologylabs.com )

in our program (www.preemo-msu.org ).

They are easy to use. it will give you both e coli and total coliforms.

Sometimes it’s hard to tell whether to classify a colony

as purple (e coli) or not. The other problem is that you don’t know exactly how much

inoculum to use a priori, so you probably should try multiple volumes.

If you use 3, it comes out to be ~$5/test.

How are you going to get the samples to the incubators?

Regards,

Kirk Barrett

Dr. Kirk R. Barrett, PE, PWS, Director, Passaic River Institute

Montclair State University, 1 Normal Ave. ML 116, Montclair, NJ 07043

phone: 973-655-7117 email: kirk.barrett@montclair.edu

web: www.csam.montclair.edu/pri

Date: Mon, 22 Sep 2008 13:30:38 -0700
From: Eleanor Ely <ellieely@earthlink.net>

Hello Gracia,

Sorry for the delay in responding; I have been out of town. Hopefully by now you have found the Winter 2006 issue of The Volunteer Monitor, with many articles on bacteria testing. The Summer 2008 issue has a follow-up letter to the editor on one of the methods (MI agar). Both can be found at www.epa.gov/owow/volunteer/vm_index.html.

Good luck!

Ellie

Eleanor Ely

Editor, The Volunteer Monitor Newsletter

50 Benton Avenue

San Francisco, CA 94112

415-334-2284

ellieely@earthlink.net

Date: Tue, 07 Oct 2008 16:27:35 -0500
From: Kris Stepenuck <kris.stepenuck@ces.uwex.edu>

Hi Gracia

We did a three year study in six states in the upper Midwest and came up with a few methods that were particularly volunteer-friendly - some of which have already been mentioned (i.e., Coliscan Easygel), but there's also 3M Petrifilm.  66% of our volunteers liked that method over the Coliscan Easygel because they had a hard time differentiating between blue and teal colonies in the Easygel method.  Though, the 3M method isn't EPA approved for water testing, it did have the statistically strongest relation to state lab methods for assessing E. coli bacteria in streams in our study.

Here's a website with our methods manual and other project information: http://www.usawaterquality.org/volunteer/EColi/index.html

Kris Stepenuck

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