Protocol for Water Sampling for Glyphosate and AMPA Residue Analysis

Other Releases
Bureau for International Narcotics and Law Enforcement Affairs
Washington, DC
April 12, 2005


The Government of Colombia's Institute of Agriculture and Husbandry (ICA)
Bogota, 2003

Annex 1: Sampling Bodies of Water for Glyphosate and AMPA Residues Analysis (ICA)


To do reliable, representative sampling in surface bodies of water to enable a quantitative determination of the presence of glyphosate and AMPA residues.


  1. Sample means the complete, homogenized accumulation of the various secondary samples taken from a body of water, to analyze its properties and list them on the label.
  2. Secondary Sample means the volume collected in the container for secondary samples in the body of water under study.
2.1 Sampling Method

According to Suarez (1), the most appropriate sampling method is restricted sampling because it is limited to the population; therefore, the sample constitutes a portion of the population. It is not possible to take an element (sample) among many existing ones.

Said sampling procedure may be considered stratified or territorial (1) based on the conditions at the sampling points, so the samples are compound.

To illustrate: From a river, three different samples may be taken: one at the source, another in its stream, and the third at the outlet. In other words: at a point before the crop under study, near the crop, and past the crop.

The sample taker must consider the points that he/she deems critical for the emission of the compound under study as strategic sampling points (2). Such points are sampling sectors or strata.

A sample composed of secondary samples will be taken in each sector or stratum. We suggest collecting secondary samples in points of turbulence (3).

The secondary samples will be mixed to obtain the sample.



  1. Rinse the secondary sample and sample containers several times (3 or 4) using the water to be sampled (3,5).
  2. For the sampling operation, be especially careful to not collect sediments (clay, mud, dirt, sand, etc.) along with the water; to avoid doing so, do not submerge the container to the bottom of the body of water; we suggest submerging it to an average depth.
  3. After you collect the samples, store them until delivery in refrigerated devices or, if not, in a cool spot out of the sun (5).
  4. To the extent possible, when collecting secondary samples, the container must be vertically submerged for the water to flow freely inside. See Figure 1. It is essential to use gloves.
  5. Use diluted sulfuric acid to obtain a pH range from 3 to 4 for your sample.


Figure 1 shows proper way to collect secondary samples;  the container must be vertically submerged for the water to flow freely inside.
Figure 1

3.1 Materials Required for Sampling


  1. A 1-liter amber-tinted glass bottle with a cap (sample container)
  2. 250-ml. wide-mouth secondary sample containers
  3. A Styrofoam cooler with a lid, to transport the samples to the lab where they will be analyzed
  4. A pair of gloves
  5. Labels to mark the water samples with the following information:
  • Location refers to data regarding the region and zone where the body of water sampled is located.
  • Collection Site refers to the location of the body of water per se, that is to say, at the source or at the outlet of a river, on a farm, near a specific crop, etc... .
  • Collection Date and Time refers to the date and time when the secondary samples were collected from the water body, to be later transferred to the sample container.
  • Number of Secondary Samples refers to the number of secondary samples collected from the body of water, which were later transferred to the sample container (1-liter amber-tinted bottle).
  • Sample Taker's Name refers to the name(s) of the person(s) who took the secondary samples and transferred them to the sample container (1-liter amber-tinted bottles), including, if possible, his/her (their) position(s) within the company in charge of collecting the sample.
  • Appearance refers to the visual inspection of the sample, determining sample characteristics such as aspect, odor, turbidity, presence of foreign elements, grease or oil, gaseous emissions, color, etc... .

An example of a label appears below.


Glyphosate and AMPA Analysis
Collection Site
Date Collected DAY MONTH YEAR
Time Collected
Number of Secondary Samples Taken
Sample Taker's (Takers') Name(s)  
  • Comments Here the sample taker adds any other information that he/she deems important regarding the sample or the collection site and/or relevant for sample analysis.
  1. Sulfuric acid and Pasteur pipette
  2. pH measuring papers

3.2 Sampling Procedure


  1. Visually determine the points where the secondary samples will be collected, taking them from mid-point in the water and near the shore, in points of turbulence.
  2. Wash secondary sample containers and sample containers with water from the sampling site (3 or 4 times) (3,5).
  3. Submerge each secondary sample container vertically so that water enters freely, until the complete volume of the bottle volume is filled. See Figure 2.
  4. Pour the full content of each secondary sample collected into the sample container (1 liter amber bottle).
  5. Collect the next secondary sample, repeating steps 3 and 4.
  6. Measure the pH, following the procedure established for that purpose.
  7. Put the cap on the container, ensuring that there is no leakage.
  8. Write the information required on the label and stick it on the sample container, using sufficient tape.
  9. Store the container in a refrigerated device or at least in a cool spot out of the sun, until it is delivered to the lab.
  10. Send the samples out in the duly sealed Styrofoam refrigerator as soon as possible.

a. Procedure for measuring pH


  1. Make sure that your hands or the tool that you use to hold the pH measuring tape are completely clean.
  2. Verify that the tape is not wet.
  3. After firmly capping the sample container, shake it.
  4. Uncap the container.
  5. Submerge the tape, but not completely, into the water in the container.
  6. Remove the tape from the container.
  7. Find the color of the tape on the pH table supplied.
  8. Repeat steps 5, 6 and 7.
  9. The pH value must be the same the two times that you measure. If not, repeat the complete procedure.
  10. Write on the label the pH value to which the color corresponds.
  11. Acidulate the sample at a pH range from 3 to 4 using diluted sulfuric acid.
  12. Write this pH value on the label.



(1) SUAREZ, F. Fundamentos de Estadastica. Aplicada al sector agropecuario. (Basic Statistics. Applied to the Farming and Livestock Sector) Rojas Ederhard Editores. Bogota. Colombia. 1999.

(2) CEPIS. Manual de evaluacion y manejo de sustancias toxicas en aguas superficiales. Seccion 5. Orientacion para muestreo, monitoreo y analisis de datos. (Manual for Evaluating and Handling Toxic Substances in Surface Bodies of Water. Section 5. Guide for Sampling, Monitoring and Data Analysis) Peru. 1991. pgs. 5,6.

(3) SECRETARIA DE AGRICULTURA Y RECURSOS HIDR´┐ŻULICOS. Tecnicas de muestreo de aguas y determinaciones en el campo. (AGRICULTURE AND HYDRUALIC RESOURCES SECRETARIAT. Techniques for Water Sampling and Field Determinations) 1st reprint of the 4th edition. 1986. 17 pgs.

(4) EPA. Pesticide Residue Analysis in Water. Training Manual. EPA-430/1-79-013. USA. 1979.

(5) WATER QUALITY BRANCH, INLAND WATERS DIRECTORATE. Sampling for water quality. Ottawa. Canada. 1983. pgs. 3-9.