PhenX Toolkit Supplemental Information
Domain: Environmental Exposures
Release Date: October 30, 2009
Water Sample - Nitrates
About the Measure
Domain
Environmental Exposures
Measure
Water Sample - Nitrates
Definition
Measure nitrates in a tap water sample from the respondent’s home.
About the Protocol
Description of
Protocol
[Note: this protocol refers to the technician as an interviewer.]
The interviewer should identify the main source of tap water for the
home. Typically this is the kitchen faucet. The cold water should be
turned on and allowed to run for at least one minute. A water sample
should be collected for a pH measurement. The interviewer should
put nitrile/latex gloves on for the next steps. A water sample is then
collected in a 125-ml polyethylene container. The top of the water
sample container is secured and then placed in water-tight bags in a
shipping container. Absorbent pads are added to the shipping
container. The sample is shipped to the laboratory for analysis.
Nitrate analysis is performed via an Environmental Protection Agency
(EPA) approved method (EPA Method 353.2) called flow injection
analysis colorimetry.
Protocol text
13.11 General Step-by-Step Procedures for Water Collection
This section includes general rules and procedures for collecting
water samples. The Interviewer follows these when collecting water
samples.
The general rules for collecting water samples are as follows:
1. Always begin the water collection by preparing for the pH
measurement.
2. Water samples are always collected from the cold water tap. If
only one tap, move temperature adjustment to the cold setting.
3. Water samples are collected from the faucet in the home that the
study participant reports as their usual source of drinking water,
regardless of the use of water softeners and Filtration
devices/systems. (See exclusion for private wells listed below.)
4. If the study participant reports using a water pitcher filtration
device as his/her usual drinking water source, collect the samples
from the cold water faucet the study participant uses to fill the
PhenX Toolkit Supplemental Information
Water Sample - Nitrates
PhenX Toolkit Supplemental Information
Domain: Environmental Exposures
Release Date: October 30, 2009
Water Sample - Nitrates
pitcher.
5. Water samples are collected from drinking water that comes from
private wells according to the following collection rules:
If two sources are used to collect water samples, each faucet is
flushed for 1 minute.
If two sources are used, record this.
6. If a filter is attached to the faucet, the Interviewer documents this
and collects the samples. The Interviewer does not remove the
filtration device.
7. If the faucet has an aerator, the Interviewer documents this and
collects the samples. The Interviewer does not remove the aerator.
8. All collection containers are kept closed until ready to collect a
sample to avoid the possibility of contaminating the sample. The
Interviewer opens only one collection container at a time. S/he
collects the sample, closes the container and then proceeds to open
and collect the next sample if applicable.
For each type of water collection, the Interviewer first completes
these general procedures for collecting water samples:
Check the faucet. If there are any aerators, strainers, hose
attachments, and/or water devices that can easily be bypassed
without the use of any tool or force, then bypass the system and
collect the sample. If it is not easy to bypass the attachment, collect
the sample at a different faucet. Do not attempt to disconnect any of
these attachments. Do not collect any water sample from a faucet
with an attachment or a faucet that is damaged.
If there are dishes or other objects in the sink, ask permission
and move them aside so that the drain is clear.
Flush the water line by fully opening the cold water tap and
allowing the water to flow for one minute. Use a timer to measure the
one minute. Document the number of minutes the line was flushed. If
the line could not be flushed, document this and proceed with the
water collection.
If the drain for the preferred water source is clogged, the
Interviewer collects from a different source and records “Yes” to the
question, “Were there any problems with the water collection
procedures?” The “Yes” requires specification of the problem, so the
Interviewer documents where the sample is collected and that the
PhenX Toolkit Supplemental Information
Water Sample - Nitrates
PhenX Toolkit Supplemental Information
Domain: Environmental Exposures
Release Date: October 30, 2009
Water Sample - Nitrates
original drain was clogged in that field.
Open a plastic-lined towel and place it on a flat surface near the
sink, such as a counter top or table.
When ready to collect the samples after the one-minute flush,
reduce the flow rate of the water to a slow steady stream to avoid
splashing when filling the containers.
When collecting water for the pH measurement, water is running
from the source at a ‘slow fill’ rate. Collect the water for the pH
measurement and submerse the pH strip.
13.12 Water pH measurement
A measurement of the pH of water is taken from study participants
whose primary source of drinking water is a private well and/or public
water supply. Interviewers are responsible for collecting a sample of
water and taking a measurement of the pH using the study-specific
protocols described in the following section. Every study participant
is eligible for water pH measurement, which is taken prior to the
collection of any water samples. Always begin the water collection
procedures with the pH water collection.
13.12.1 Equipment and Supplies
Interviewers are provided with the following supplies:
Reusable Beaker
Water pH strips (Baker-pHIX, pH 4.5-10)
pH color reference chart
Absorbent lined chux
Timer
13.12.2 Step-by-Step Procedures for Water pH Measurement
The water sample for pH measurement is taken from the same
faucet as the collected samples. It should be taken from the cold
water faucet in the kitchen whenever possible. If the sample cannot
be taken from the kitchen, the Interviewer collects water from a
bathroom sink, using any cold water faucet without an attachment.
The pH measurement of a separate water sample (other than those
collected for shipment) precedes collection of the water samples as
designated by the water collection protocol. The Interviewer rinses
and dries the reusable beaker between interviews.
Steps that the Interviewer should follow for measuring pH are as
follows:
1. The Interviewer flushes water line using timer to measure one
minute. The Interviewer sets up pH measurement materials and
water collection materials while the line is flushed.
PhenX Toolkit Supplemental Information
Water Sample - Nitrates
PhenX Toolkit Supplemental Information
Domain: Environmental Exposures
Release Date: October 30, 2009
Water Sample - Nitrates
2. After the line has been flushed, the Interviewer rinses the reusable
pH measurement beaker three times with water from the flushed
source.
3. The Interviewer collects approximately 60ml of water in the
beaker.
4. The Interviewer places one pH strip in the water, with all three
color blocks submerged, then starts the timer.
5. The color blocks must be submerged in the water for 10 minutes.
6. After the pH strip has been placed in the water and the timer has
been set, the Interviewer proceeds to collect water samples
according to study protocol.
7. Once ten minutes have elapsed, the Interviewer removes the strip
from the water and immediately compares the strip to the color
reference chart.
8. The Interviewer determines the pH number associated with the
color blocks that correspond to the colors on the test strip and
documents this.
9. The Interviewer discards the water in the sink and dries the
reusable beaker.
10. If all water samples were not collected during the ten-minute
interval, the Interviewer proceeds to complete collection of all water
samples, otherwise, the Interviewer cleans the collection area and
gathers any waste generated to discard it away from the study
participant home.
13.16 Step-by-Step Procedures for Private –Nitrate Water Sample
The nitrate sample is collected in a dark 125-ml polyethylene
container. After completing the general collection steps listed in
13.11, the Interviewer proceeds with the following steps:
1. Put on a pair of disposable latex gloves and a disposable
laboratory coat (if not already wearing).
2. Open the collection kit marked Private and remove all of the
components included in the kit.
3. Place nitrate bottles (one 125-ml dark container) in an upright
position. Place the transmittal forms away from the collection
PhenX Toolkit Supplemental Information
Water Sample - Nitrates
PhenX Toolkit Supplemental Information
Domain: Environmental Exposures
Release Date: October 30, 2009
Water Sample - Nitrates
location. This will eliminate the potential for spills onto the transmittal
forms.
4. Do not remove the absorbent pads from the 6x10 and 10x10
watertight transport bags.
5. Confirm that the collection container and the Water Sample
Repository Transmittal Form are labeled with the correct sample ID
label. The Water Sample Repository Transmittal Form is also labeled
with a PID.
6. When removing the cap from a sample bottle, be careful not to
contaminate the cap or neck by contact with the fingers. Do not rinse
the sample bottle.
7. Carefully open the bottle and fill to the top of the bottle’s ‘shoulder’,
the point where it narrows, before it ends at the 'cone' where the cap
is screwed.
8. Once all samples are collected, turn off the water supply.
9. Place the collected samples into the appropriate watertight bags.
10. The nitrate sample is packaged in the 10x10 watertight bag. Be
sure to verify that an absorbent pad is included in the bag.
11. Remove as much air from each bag as possible prior to sealing.
This can be accomplished by rolling the bag around the sample
containers.
12. For each bag, remove the blue protective tape from the transport
bag and seal.
13. For nitrate samples it is important to package the samples with
frozen ice packs as soon as possible after collection. These samples
must be maintained at 0° – 6°Celsius.
14. Document the results of water sample collection on the Water
Sample Repository Transmittal Form (for the arsenic samples).
15. Be sure to clean the work area thoroughly. Wipe the area dry and
clean up any spills. Discard the plastic-lined towel, gloves, and any
paper towels into a small trash bag. Remove the trash bag from the
study participant's house and discard it with the other waste from the
visit.
16. Ship the samples according to the shipping protocol.
PhenX Toolkit Supplemental Information
Water Sample - Nitrates
PhenX Toolkit Supplemental Information
Domain: Environmental Exposures
Release Date: October 30, 2009
Water Sample - Nitrates
Participant
Age 18+
Source
New England Study of Environment and Health, Version 5
Interviewer Manual, Sections 13.11, 13.12, and 13.16, 2003
U.S. Environmental Protection Agency (EPA). 1993. Method 353.2:
Determination of Nitrate-Nitrite Nitrogen by Automated Colorimetry.
Retrieved on May 11, 2009, from
http://www.epa.gov/waterscience/methods/method/files/353_2.pdf
Language of
Source
English
Personnel and
Training Required
A trained interviewer/technician collects the tap water sample and
returns the sample to the laboratory for analysis. An adult from the
residence could collect the tap water sample although this is not
routinely done.
A trained laboratory technician should perform all post-collection
processing and analysis. The U.S. Environmental Protection Agency
(EPA) standard method 353.2 for analysis of nitrates should be
employed.
Equipment Needs
Water collection supplies are necessary to measure pH and collect
the tap water sample for nitrate analysis. Laboratory instruments are
necessary to perform flow injection analysis colorimetry on the
sample. Tap water samples samples may be shipped to laboratories
that specialize in these types of analysis.
Protocol Type
Laboratory Analysis
General References
None
PhenX Toolkit Supplemental Information
Water Sample - Nitrates