Protocol for Soil 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 Ministry of the Environment's Institute of Hydrology, Meteorology, and Environmental Studies (IDEAM)
Bogota, 2003 

 Soil Sampling for Glyphosate and AMPA Residue Analysis



The Colombian Technical Standards Institute (ICONTEC), in 1994 NTC 3656 standard, sets forth the methodologies for taking soil samples for the purpose of determining contamination and ensuring that lab analysis can evaluate their quality and contamination level. The guidelines in this standard were taken into account in the soil sampling proposal.


The sampling unit will be one hectare in which 12 samples will be collected, 6 of which will be collected in one sector of the lot and later compounded or joined to produce one sample; the other 6 samples will be collected in the remaining sector of the hectare, to produce the second sample. These two compound samples will be used to make physical-chemical, glyphosate and AMPA analyses.

The locations will be randomly selected in areas affected by the presence of illicit crops (the sampling obtained prior to glyphosate spraying may be used as a reference pattern).

Sampling Methodology

Soil. In the selected areas, take samples in the central zones where a greater concentration of the applied formula is believed to be found, using 12 sampling points selected at random (Figure 3). Collect minimum 1,000 g. from each site, at a depth of 20 cm. It is important to write down the soil temperature and moisture in situ on each lot.

Figure 3. Sample-taking Schema for Each Point Selected in Areas Sprayed with Glyphosate-based Formulas


Figure 3. Sample-taking Schema for Each Point Selected in Areas Sprayed with Glyphosate-based Formulas

Collect the soil samples in Kraft paper bags, then put them into large Ziploc plastic bags and properly label (using a waterproof indelible marker). In addition, in each bag place a small identification format of the sample, protected by a smaller bag, of those used in IDEAM Geomorphology and Soils Subdivision, and also separately attach the field form (Annex 1).

For the physical-chemical and residue analysis of pesticides, create two samples from the initial 12, joining the 6 taken from one sector to make up one sample and the remaining six from the other sector to make up the second sample, as indicated in Figure 4.

Figure 4. Schema Indicating How to Make Up the Compound Mixes for physical-chemical and residue analyses of pesticides.

Figure 4. Schema Indicating How to Make Up the Compound Mixes for physical-chemical and residue analyses of pesticides.

Sampling Format

Geo-reference the collected samples and fill out the form supplied by IDEAM for soils. In the post-spraying sample formats, remember to add additional information regarding the date, time, and operational and environmental conditions of the aerial spraying (i.e. wind speed, application height, etc...); this data will be supplied by the Anti-Narcotics Police and IDEAM.

Glyphosate and AMPA Residues

Soils. Send the soil samples, following the technical guidelines provided by the Canadian CTQ laboratory. Send duly labeled 500 g. of soil with the corresponding identification form.

Soils. Collect the samples in quantities of 500 g. and put them in Kraft paper bags that will be later packed in plastic bags and duly labeled, following the recommendations.


One person will have the authority of being responsible for receiving and packing the samples, sealing and opening the coolers after each sampling. This person will verify the presence and condition of all of the samples, based on the forms on each cooler; this person will also verify the individual sample form. The team members must constantly supervise and watch over the samples and coolers during sample taking, storage and transportation.


Soil. Collect the soil samples following the provisions in number 4.2.1, checking that the identification sheet code matches the code on the bag. Also, the person in charge of custody must record on the forms if sampling conditions were met as well as the sample condition. Once at the air base, in the presence of the individual in charge of the custody chain and of witnessing (procedure that will be recorded on the forms), this person will proceed to create the two samples out of the 12 secondary samples for analyzing pesticide (glyphosate) residues and for physical-chemical analysis, taking from each bag approximately 100 grams; these new two compound samples must be duly labeled, writing the codes of the mixed samples on the identification sheet.

Glyphosate and AMPA samples must be coded and stored following the Canada Laboratory guidelines and the person in charge of custody will compound these samples to form two samples. The sample will be delivered to Bogota and handed over to the person who will act as Bogota-Canada custodian.

Transportation. The samples must be transported from the sampling site to the air base. There the custodian receives the samples and verifies the identification forms and the sample condition and then proceeds to separate the samples for physical-chemical and residue analysis, clearly identifying the procedure followed on the form. Once this process is done, the samples are stored in Styrofoam coolers with dry ice, or following the procedure set forth by the Canadian lab. Then they are sealed in the presence of witnesses and immediately taken to Bogota. In the lab, the person in charge of the Bogota-Canada custody and the authorized personnel at the different labs open the samples, verify the forms, deliver the samples according to the analytes, sign the delivery act writing down the condition, and seal the cooler again for its transfer to Canada.




Diagonal 97 No 17 - 60 Bogota, DC, Colombia.
PBX 6356230 Web

Geomorphology and Soils Subdivision

Tel. 6356049, Fax 6356130, Piso 3
Bogota, DC

Chemical Physiology Program
Oficinas Parque industrial de occidente (HB)
Cra. 129 # 29 - 57 Bodega 17 - 18

Tel: 4181181 -  4181215


Profile #


Day Month Year
Provincial Department Settlement County
Coordinates LW:  ' '' LN:  ' ''
Horizon Depth
Limits From      cm.    to      cm.
Analysis Requested          
Sample   Counter-sample    




This protocol has been modified in some technical aspects to adjust it to the difficult logistics and field conditions encountered. These modifications have been granted approval by the Ministry of Agriculture and Rural Development Colombian Framing and Livestock Institute (ICA), by Ministry of the Environment, Housing and Territorial Development technicians who have been present when all of the samples were taken, as well as by professional opinions from personnel at the Agustin Codazzi geographical Institute National Soils Laboratory.

These modifications are summarized below.

  • The samples are not packed in "Kraft" paper bags because the moisture in the soil dissolves this type of paper, adding Boron (Br) and organic matter to the soil, altering the samples.
  • Samples are collected in two recyclable plastic bags (LDPE) with airtight sealing (Ziploc type). The double bagging prevents losing the sample if the outside bag is punctured or if there is cross contact between samples.
  • There are fewer secondary samples per area unit because there is little time from when the helicopter descends to when it must take off again, due to the hostile presence of outlawed groups. However, the samples are made up of several secondary samples (minimum 4) collected using the suggested methodology.
  • Once taken, the samples are preserved in a portable cooler with ice, at temperatures below 4 degrees centigrade, temperature below which there is no glyphosate metabolization. The ice in the cooler is kept in airtight bags, so that, when it melts, the water does not enter into direct contact with the samples.
The glyphosate and AMPA analyses were made in a USDA-ARS laboratory at the University of Mississippi (Oxford, Mississippi).