Nitrogen testing kits or probes
From: HANSON Steve [mailto:HANSON.Steve@deq.state.or.us]
Sent: Wednesday, June 22, 2005 6:56 PM
To: Volunteer water monitoring
Cc: Sandy Lyon
Subject: [volmonitor] Nitrogen testing kits and probes
I am requesting feedback from groups that have used nitrogen testing
kits or probes. I'm interested in what kits/probes you have used, what
the detection limits are (please specify mg/L as N or NO3), and how the
kits performed for you. If you were able to compare the results from
your kit/probe to samples analyzed at a laboratory, or any other quality
control testing you did, I'd be very interested in how the samples
I work with volunteer groups all over the state of Oregon who do water
quality monitoring. I am trying to determine what methods could be used
by Oregon groups to identify nutrient sources.
Thanks for your response.
Volunteer Monitoring Specialist
Oregon DEQ Laboratory
Toll Free: 1.800.452.4011
2020 SW Fourth Ave. Suite 400
Portland, OR 97201
From: Linda Green [mailto:LGreen@uri.edu]
Sent: Wednesday, August 17, 2005 11:26 AM
To: HANSON Steve
Subject: RE: [volmonitor] Nitrogen testing kits and probes
I am program director of a volunteer monitoring program in RI, URI Watershed Watch, housed at Cooperative Extension. We have an analytical lab and use an Astoria-Pacific segmented continuous
flow nutrient autoanalyzer for our nutrient anlyses, since our waters are typically <2ppm in any form of nitrogen, which I think is pushing the limit on kits. I was fortunate that our Dean contributed ~ 75% of
the $42K it cost to purchase the autoanalyzer last year, it was replacing a 15 year old model that had been purchased by a professor I worked with. The prof departed without the analyzer, I took it over.
URI Cooperative Extension Water Quality
Department of Natural Resources Science
1 Greenhouse Road
Kingston, RI 02881-0804
Date: Wed, 22 Jun 2005 16:23:26 -0700
From: Lesley Jones <firstname.lastname@example.org>
Subject: Re: [volmonitor] Nitrogen testing kits and probes
We only take grab samples and process in the lab. The methodology is:
TKN - EPA 351.2, sulfuric acid to pH<2 preservation, 4C, analyze within 48 hrs
Nitrate/Nitrite - EPA 300.0, 4C, analyze within 48 hrs
TP - EPA 365.3, sulfuric acid to pH<2 preservation, 4C, analyze within 28 days
The weird thing is that the Practical Quantitation Limit for TP is above the guideline of 0.05 mg/L. If there is a non-detect, the result is reported as one half of the PQL and is above the guideline. Therefore, no matter what result you get, the guideline is exceeded. The City of Bend lab is working on this issue to see if they can lower the PQL for TP.
Regarding nutrient probes, we have never used them, but I hear rumor that 'they are not as good as lab analyses methods'. I personally like to use meters and probes when possible, so I am interested to hear what you find out from this inquiry.
Lesley Jones, Water Quality Specialist
Upper Deschutes Watershed Council
Water Quality Monitoring Program
Date: Thu, 23 Jun 2005 10:18:42 -0400 (EDT)
Steve, our nutrient samples are analyzed by the National Parks Service-Cape Cod National Seashore (CCNS) lab. In the past we used the County health department lab and the detection limits were not sensitive enough (especially for P) because they were primarily set up to do drinking water samples, not lake/pond ones. I have passed on your question to the lab chemist at the CCNS in hopes she will reply.
I am not aware of any field instruments that are inexpensive enough for volunteer groups to use, which also meet the detection limit requirements, or would be approved by some of the state agencies who require analyses be done under an approved QAPP and a certified lab. We do use YSI DO meters in the field for DO, but follow up with a water sample for Winkler analysis at a lab (for marine samples), if DO readings are below 5.0 mg/L.
I am interested in what you find out!
Orleans Water Quality Task Force
Editor's note: Steve Hanson summarized the rest of the responses he received:
Responses are summarized in the following manner:
Nitrogen Testing Kits Comparison Information.
a. Kit Description
c. Detectioin Limits/ Resolution
1. Jacqueline Fern OSU Extension Service Water Quality Educator
a. LaMotte Zn Based test Kit (Order Code 3354?)
b. Zinc Reduction Octa-Slide color comparator
c. "0" to 15 in increments of 1 ppm NO3-N
d. "goal is not to provide precise readings...but reasonably accurate
e. Recently switched from Hach colorwheel method b/c of concerns about
2. Natalie Galatzer, Prairie Rivers Network, Illinois Stream Team,
Water Quality Intern
a. LaMotte Kit Code 3354
b. Zinc Reduction Octa-Slide color comparator 0, 1, 2, 4, 6, 8, 10 and
15 ppm NO3-N
d. It's colorimetric, so you can see that perhaps the actual value
lies between 0 and 1, but you can't determine what that value is with
3. Ginger North, Stream Watch Coordinator, Delaware Nature Society,
302-239-2334x100, Fax 302-239-2473, email@example.com,
a. LaMotte Field Kits Code 3110
b. Cadmium Reduction Octet color comparator
c. 0.025 (error? I can't find any LaMotte kits with this low a DL) -
10 ppm NO3-N. LaMotte reports Range/Sensitivity as: 0.25,0.5,1.0, 2.0,
4.0, 8.0, 10.0 ppm NO3-N
d. "Under quality control testing the nitrate kits compare better than
the phosphate kits"
e. "The data is published by DE DNREC for their Watershed Assessment
Report - 305(b)"
4. Chris Sullivan, Project SEARCH Coordinator, (203) 734-2513, FAX
203-922-7833, www.sciencecenterct.org/projectsearch, Center for
Environmental Research Education, Kellogg Environmental Center, 500
Hawthorne Ave., Derby, CT 06418
a. LaMotte Colorimetric analysis order code 3649-SC
b. Cadmium reduction with Colorimetric % Transmission determination.
c. 0.02 - 3.01 ppm NO3-N in increments increasing from 0.01 to 0.14
relative to magnitude of concentration. LaMotte reports sensitivity of
0.05 ppm NO3-N
d. "The results are slightly less reliable down at the lower end of
the scale, but have corresponded fairly well with the health lab values
in past years of Project SEARCH"
e. "We used to run replicate samples with the state health lab and the
school groups were usually statistically similar to the health lab