The Question

Date: Mon, 25 Jan 2010 15:01:22 -0500
From: Kim Cressman <kcressman@capecoral.net>

Hi everybody,
Volunteers in my program have recently begun using LaMotte kits to take DO measurements. One of the volunteers is interested in profiling the water column by using some sort of contraption to sample at different depths (surface, 0.5 m, 1 m). What sort of contraption is yet to be determined – do any of you regularly take DO samples below the surface? What equipment do you use? We obviously don’t want to introduce oxygen into the sample, and we don’t want to introduce any unnecessary mixing into the water column either.
Any thoughts or tips would be appreciated.
Thanks,
Kim Cressman
Environmental Biologist
City of Cape Coral
kcressman@capecoral.net

Responses

Date: Mon, 25 Jan 2010 16:28:44 -0500
From: "Rathbun, Joseph (DEQ)" <RATHBUNJ@michigan.gov>

Look at the LaMotte DO Water Sampler – p. 337 in the Forestry Suppliers catalog #60. $101

Date: Mon, 25 Jan 2010 16:31:14 -0500
From: Ann Schenk <aschenk2@mac.com>

Kim,
The 0.5 m is easy -- hold sample bottle upside down while immersing it to 1/2 meter, turn right-side up and cap while holding it at that depth. Deeper than that, and you are looking at Kemmerrer, Van Dorn or Niskin bottles, or a pump and hose. The sampling bottles run in the $400-$600 price range to buy, any they can be rented from several companies.
See links below for more details on selection and usage of sampling bottles.

http://water.usgs.gov/owq/FieldManual/Chapter2-Archive/Archive/Ch2_contents.html

http://www.cee.vt.edu/ewr/environmental/teach/smprimer/kemmerer/kemmerer.html#Recording

The pump and hose option is generally home-made. A 12-V bilge pump and garden hose is easy if working from a boat, but not practical if wading. Batteries are heavy and dangerous in that situation. Have not tried "fountain" or large aquarium pumps as they usually need house power, which is generally not practical.
Ann Schenk

Date: Mon, 25 Jan 2010 17:00:07 -0500
From: URI Watershed Watch <uriww@etal.uri.edu>

The most recent Volunteer Monitor newsletter included directions for making a variety of water samplers, included discrete depth samplers for dissolved oxygen. Please see: http://www.epa.gov/volunteer/issues.htm to download a pdf.
Our program uses the LaMotte Water Sampling Bottle (3-0026) for sampling as 1 - 20 meters with good success. They cost about $170, and you have to add your own calibrated line and weights, but they’ve been real work horses for us!

Good luck!
Elizabeth Herron
URI Watershed Watch
Phone: 401-874-4552
Fax: 401-874-4561
Web: http://www.uri.edu/ce/wq/

Date: Mon, 25 Jan 2010 14:08:02 -0800
From: "Williams, Gene" <Gene.Williams@co.snohomish.wa.us>

Kim,
We have had volunteers doing DO profiles in lakes using LaMotte kits and DO samplers similar to the one Joseph noted or using Van Dorn-type samplers. We use the student water samplers from Aquatic Research Instruments (http://www.aquaticresearch.com/student_water_samplers.htm) (about $200) , but they also make the DO samplers.
I am inserting an excerpt from the monitoring procedures in our QAPP (24 KB pdf file) that describes in detail how to use the DO sampler or Van Dorn vertical sampler to take DO measurements at depth being careful not to introduce air into the samples. It’s way more detailed on all the testing steps than you need, but you can find the description of using the samplers.
I hope this example from our program helps.
Gene Williams
Snohomish County Public Works
Surface Water Management
3000 Rockefeller Avenue, M/S 607
Everett, WA 98201-4046
(425) 388-3464 x4563
gene.williams@snoco.org

Date: Mon, 25 Jan 2010 17:57:15 -0800 (PST)
From: Revital Katznelson <revitalk@sbcglobal.net>

Kim,
We made widespread use of the upright sampling apparatus in California; this apparatus holds the 60-ml DO bottle inside a bigger chamber and it gets flushed with several volumes of water before the sample is used for the Winkler titration. There are several commercial models you can choose from (thanks, all of you who responded), and you can also build one yourself based on the same principle. You may find a useful drawing in our SOP 3.1.1.2 in the Clean Water Team Guidance Compendium, at
http://www.waterboards.ca.gov/water_issues/programs/swamp/cwt_guidance.shtml
Here is another option:
Way back in the 1980s I rigged a syringe-pump apparatus, made of a 60ml syringe, tubing, and a three-way stopcock, for collection of water samples at defined depths below the water surface without contact with air. I used the samples for analyses of dissolved oxygen, sulfides, and other water quality characteristics. It works really well for depths up to 3 meters. I built it again in the 1990s with my colleague, and the instructions were published as SOP 2.1.1.3 (Construction and Use of a Syringe Pump Apparatus) in the Clean Water Team Guidance Compendium, at
http://www.waterboards.ca.gov/water_issues/programs/swamp/cwt_guidance.shtml
Good luck,
Revital
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Revital Katznelson, Ph.D.
Environmental Scientist
Berkeley, California
revitalk@sbcglobal.net
510 406 8514

Date: Tue, 26 Jan 2010 12:39:07 -0500
From: nolnacsj@aol.com

We use direct reading instruments like a YSI, and take measurements at different depths (profile) for most of our volunteer monitoring efforts in both marine, and freshwater lakes and ponds. You can also collect a Winkler sample, but it requires volunteers to fix the sample in the field with small chemical packets, and normally a certified lab does the analyses which costs money. When we do collect DO samples (Winkler bottles), we use a Niskin sample bottle for collection at different depths. There is a special procedure used when collecting a Winkler sample so that extra oxygen is not introduced. However, based on my own experience with volunteer monitoring efforts, the direct reading instrument is the way to go. This also allows you to collect the temperature data you need for your DO/temp profile. We only collect a Winkler sample when the DO reading using the YSI is below 5.0 mg/L.

There are some excellent volunteer monitoring programs and technical resources available in Southwest Florida. I attended a great conference in Punta Gorda about 6 years ago. I remember Port Charlotte had a group, and so did the Peace River. SW Florida has a good water resources group too. I am sure there is a very large water quality network available to you. Just search the Net. The folks at the Ding Darling (national wildlife preserve) on Sanibel can probably help you also. I live in MA on Cape Cod, but just arrived on Sanibel yesterday where I will be for 2 months, so if I can help you more, please feel free to contact me. nolnacsj@aol.com

Judy
Orleans Water Quality Task Force
Orleans, MA (Cape Cod)

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