SOP EM-03 Page 1 of 4

Collection of Water Samples 

Revision: #10 Replaces: 2/19/14 version Effective: 9/3/19

1. Purpose and Scope: Water samples are collected to measure the amount of pesticide in the

water. There are different procedures for collecting standing water, flowing water, and ground

water samples. This SOP describes how to collect, transport and store standing water and

ground water samples. If flowing water is to be collected, contact the Environmental

Compliance Team at (301) 851-2351 (Mike Hennessey) or (301) 851-2345 (Kai Caraher) for

instructions and equipment requirements. Any instructions on water sampling and

documentation found in the Environmental Monitoring Plan (EMP) for the Program under study

supersedes instructions contained in this SOP.

2. Supplies Required: To request sampling supplies, contact the monitoring supplies 

coordinators, Lisa Mosser (305) 278 4902, or Richard King (305) 278 2905, Center for Plant 

Health Science and Technology, Miami, or email the Environmental Monitoring Supplies 

Checklist to lisa.k.mosser@usda.gov or richard.a.king@usda.gov.

2.1 1 gallon, collapsible plastic "cubitainers"

NOTE: cubitainers may introduce material that will interfere with the analysis of 

some compounds. Please check with CPHST when ordering supplies. If the 

pesticide to be analyzed is among those that might be affected by the cubitainer, 

then the laboratory will supply glass containers instead. 

2.2 pH indicator paper or pH meter 

2.3 sodium sulfate (pre-packaged 5 gm vials) *

2.4 sulfuric acid (in a plastic squeeze bottle) *

*NOTE: most pesticides used by PPQ are stable in acidic water. However, check 

with CPHST when ordering supplies to determine that the acid and buffer 

specified herein are correct for the pesticide being sampled. If not, the laboratory

will provide alternate materials and instructions for stabilizing the sample. 

2.5 12"x 12" resealable plastic bags

2.6 “grab sampler” – a large-mouthed plastic jug firmly attached to a pole 

2.6 field log book 

2.7 ice chest with bagged or containerized ice or frozen blue ice packs (obtain locally) 
SOP EM-03 Page 2 of 4

Collection of Water Samples 

Revision: #10 Replaces: 2/19/14 version Effective: 9/3/19

2.8 environmental monitoring forms (APHIS Form 2060) 

2.9 indelible marker

2.10 thermometer

2.11 dissolved oxygen test kit or dissolved oxygen meter 

3. Collecting Stationary Water Sample:

3.1 Remove the cap and inflate the cubitainer by exhaling into the opening of the 

cubitainer.

3.2 Partially submerge the opening of the cubitainer into the water body so that the 

water flows in until the cubitainer is slightly more than half full 

or 

to obtain a sample from a deeper portion of the water body use the “grab sampler” 

to collect water and dispense it into the cubitainer. Repeat until the cubitainer is 

slightly more than half full.

3.3 Check the pH of the sample, adjust if necessary, and add the stabilizer. See 

Section 5 of this SOP for instructions. 

3.4 Collapse the cubitainer containing the stabilized sample to expel most of the air 

and screw on the cap securely. 

3.5 Label the sample with the indelible marker with a unique identifier that will allow 

the sample to be matched to its documentation.

3.6 Place the sample in the ice chest to keep it chilled until it can be transported from 

the field and placed in a freezer for storage until shipping. 

3.7 Measure and record the dissolved oxygen content of the water body, using the test 

kit or dissolved oxygen meter (refer to EM-21, Measurement of Dissolved Oxygen 

in Water Samples).

3.8 Measure and record the temperature of the water body being sampled.
SOP EM-03 Page 3 of 4

Collection of Water Samples 

Revision: #9 Replaces: 2/19/14 version Effective: 9/3/19

4. Collecting Groundwater Samples (see SOP EM-14, Collection of Ground water Samples):

4.1 Remove the cap and inflate the cubitainer by exhaling into the opening of the 

cubitainer.

4.2 From as close to the well head as possible (i.e. before any water treatments), open 

a spigot and allow the water to flow for several seconds (enough to allow fresh 

water to enter the pipes between the well and the spigot. This is normally 

indicated by a temperature change in the water).

4.3 Place the cubitainer opening under the flow and allow the container to fill to 

slightly more than half full.

4.4 Check the pH of the sample, adjust if necessary, and add the stabilizer. See 

Section 5 of this SOP for instructions. 

4.5 Collapse the cubitainer containing the stabilized sample to expel most of the air 

and screw on the cap securely. 

4.6 Label the sample with the indelible marker with a unique identifier that will allow 

the sample to be matched to its documentation.

4.7 Place the sample in the ice chest to keep it chilled until it can be transported from 

the field and placed in a freezer for storage until shipping. Dissolved oxygen and 

water temperature should not be measured for ground water samples. 

5. Adjusting pH and Stabilizing a Water Sample:

5.1 Measure and record the pH of the water using the pH meter or by dipping one end 

of a strip of pH paper into the sample. 

5.2 If the pH of the water sample is greater than 5, add 3-5 drops of sulfuric acid to 

the sample. (NOTE: Sulfuric acid can cause chemical burns. Flush skin with 

water if exposure occurs. Reference the Material Safety Data Sheet provided by 

CPHST with this chemical.) Mix the acid and water, and measure the pH again 

with a fresh piece of pH paper or the pH meter. Repeat this step as until the pH of 

the water sample is about 5.

5.3 Record the final pH measured in step 5.2. 
SOP EM-03 Page 4 of 4

Collection of Water Samples 

Revision: #9 Replaces: 2/19/14 version Effective: 9/3/19

5.4 Stabilize the water sample by adding 3 sodium sulfate vials to the water sample 

container. Cap the sample container and mix by inverting the container until the 

sodium sulfate is dissolved. (NOTE: most pesticides used by PPQ are stable in 

acidic water. But check with CPHST when ordering supplies to determine that 

the acid and buffer specified herein are correct for the pesticide being sampled. If 

not, the laboratory will provide alternate materials and instructions for stabilizing 

the sample.)

6. Documentation:

6.1 Record all observations in the field log book (see SOP EM-12, Using a Field Log 

Book). For stationary water, record the estimated average depth and the surface 

area of the water body. Describe any vegetation between the treatment site and 

the sample collection site, or any other factors that you think might influence the 

amount of pesticide being deposited on the water body. For ground water 

samples, be sure to record the soil type, ground cover, and the topography of the 

treatment site. For all samples, include GPS coordinates and a sketch of the 

sample location and its relation to the treatment site and any sensitive site(s) 

in the vicinity. The sketch should include an approximate scale and a North 

arrow. Annotated aerial photographs, topographical maps, or photographs 

of the site in addition to the sketch are useful. 

6.2 Complete an APHIS Form 2060 for each water sample. 

6.3 Retain the pink copy of Form 2060 for your records and distribute the remaining 

copies as specified in the EMP.

7. Packaging and Shipping:

7.1 Package and ship the water samples to the laboratory as described in SOP EM-17, 

Packaging and Shipping of Samples.