Evaluation of the Effects of Glyphosate on Human Health in Illicit Crop Eradication Program Influence Zones

Other Releases
Bureau for International Narcotics and Law Enforcement Affairs
July 2003
Washington, DC

Republic of Colombia
Ministry of Social Protection

National Health Institute
Epidemiology Sub-directorate and National Reference Laboratory - Research Sub-directorate

Bogota, July 2003



In compliance with its responsibility under the Environmental Management Plan set forth for the Illicit Crop Eradication Program, the Ministry of Social Protection has promoted the creation of this project whose purpose is "To explore the possible effects of glyphosate on human health as a result of aerial spraying" linked to the application plan to be carried out in seven (7) provincial departments in the country.

After a process of discussion and analysis of several epidemiological evaluation proposals, we reached the consensus of doing a descriptive case study, the main purpose of which is to determine if the spraying is innocuous or, to the contrary, if it represents some risk to the population. In this manner, we intend to answer to one of the doubts that has been a motive for concern in the community and organizations, both public and private, since the spray program was initiated in Colombia.

We opted to do this study as one of the most viable alternatives considering the limitations that we encountered in carrying out this type of work; the main one being the high cost involved. That is why we chose seven (7) provincial departments in which public order conditions were more favorable to carry out the project.


1.2. Research Problem

The problem of the indiscriminate use of pesticides in the most varied of farming and forestry activities by the rural populations in the areas of influence of aerial spraying has led not only to these human nuclei being seriously affected by exposure to a variety of substances while working, but also by exposure through the air and in the food and water that they use; this also occurs to the population at large, through pesticide residues. That is to say that the whole population is exposed to a health risk that is not sufficiently appreciated and perceived by the corresponding health authorities.

Also, these toxic substances are not only eliminating pests but are also affecting the local ecosystems, especially bodies of water, thus endangering the very lives of many species, especially birds, and considerably reducing the life of the soil, wildlife, and benign insects, which are needed to maintain a natural balance.

These pesticides can be found everywhere and are easy for any person to access, even children. This is a situation that is especially serious if we take into consideration that a broad variety of chemical substances are used in illicit crops.

In a report prepared for the National Directorate of Dangerous Drugs (DNE) and the United States Embassy[1] it was verified that 98.7% of illicit crop growers use insecticides and fungicides to control pests and disease; 92.5% use chemical fertilizers, and 95.5% control competition from other plants by using herbicides. Furthermore, the research done by Instituto SINCHI[2] showed that, unlike what producers do with subsistence crops, illicit crop growers go to great lengths to weed their illegal crops and chemically control insects and pests[3].

SINCHI mentions that the economic logic behind this behavior is due to the fact that for food crops growers want to take full advantage of the natural fertility of the soil, whereas for coca crops, because of revenue expectations, producers feel obliged to incorporate chemical technology[3].

It has been established that there are no significant differences between producers in different coca crop regions, as far as how intensely they use farming chemicals, no matter if they have small crops or industrial-type crops. Along these lines, URIBE (1999)[1] established the use of at least 75 different brands of farming chemicals. Regional differences regarding the type of substances used are determined by market availability; many of them enter into the crop areas directly as contraband [3].

Table 1 shows the main herbicides used on coca crops, based on DNE data - Colombian Drug Information System (SIDCO).


Table 1. Herbicides Used on Coca Crops

Commercial Name


Of Use

Toxicological Category




II LD Oral: 150 mg/kg




IV LD Oral: 4,300 mg/kg




I LD Oral: 699 mg/kg

Round up



IV LD Oral: 4,300 mg/kg




III LD Oral: 1,780 mg/kg




III LD Oral: 5,000 mg/kg





Source: DNE- SIDCO

It is interesting to note that glyphosate is one of the substances most used by illicit crop producers.

The number and variety of insecticides and fungicides is even greater than herbicides and the use of toxicological category I and II substances is notorious; therefore, we expect that the effects on the ecosystems and, particularly on the community, to be quite negative; this situation is compounded if we take into account the fact that many of the farmers still believe the theory that "the greater the quantity and concentration of the farming chemical, the more effective it will be". That is why it is common that the doses used are not the doses recommended by the manufacturer[3].

Among the fungicides used, we mention Mancozeb (Manzate), Koper oxychloride (Oxicloruro de cobre), Carbendazin (Bavistin). Among the insecticides, we name: Metamidophos (Tamaron), Carbaryl (Sevin), Metomyl (Metavin), Carbofuran (Furadan), Prophenophos (Curacron), Endosulfan (Thionil), Methyl Parathion (Parathion), Lambda Cyhalothrine (Matador), Malathion (Malathion), Monochrotophos (Nuvacron), Chlorpiriphos and Cipermerine Chlorpiriphos (Lorsband), Cipermetrine and Diacinon (Comboy), Cipermetrine (Politrin) [3].

The chemical substances that illicit crop growers introduce into the ecosystems on a daily basis cause, among others, the following effects:

1. Contamination of resources: pesticides are capable of contaminating the sources of potable water that humans and animals drink, sources of bodies of water, rivers, and seas. Farming chemicals can reach water sources by following any of the means indicated below.

  • Percolation or lixiviation of pesticides applied to the surface of the soil
  • Discharge of liquids remaining from the application
  • Discarding empty containers
  • Flooding or overflow of rivers that reach storage areas[3].

The consequences of this contamination are the loss of aquatic flora and fauna; the loss of the resource as a source of water and nourishment; and the intoxication of human beings and animals[3].

2. Contamination of the soil: some pesticides are directly applied to the soil (herbicides such as 2,4,D and insecticides such as Metomyl). There are others that reach the soil indirectly by dripping from the plant, dripping from the application equipment, being dragged by raindrops (Clordano, Parathion), washing the application equipment, discarding containers, etc...[3] .

Discarding containers and leftover product: Normally the peasants discard the pesticide containers, the product leftover from the spray processes, and the product remaining in the spraying equipment after washing it[3] in the surroundings (soil and sources of water, incineration, etc...). Many recipients are recycled to use them as containers for daily chores and preparing food; usually glass recipients are used for holding liquids (in some regions we have found that the peasants use the Gramoxone recipients for their guarapo, a homemade brew), kerosene or water; metal recipients are used to heat or hold water and aluminum recipients are used as containers in the base and refining labs[3].

3. Disposal in septic tank holes: in rural areas of Colombia it is customary to dig holes near the dwellings and deposit garbage in them. Unfortunately, the garbage is not separated and all kinds of materials are put there together, no matter if they are biodegradable, toxic or not[3].

4. Open air incineration: This may cause even greater inconveniences than mere dumping. When exposed to heat, some products emit dioxins and furanes, whose toxic power is greater than the original product's toxic power[3].

Each one of the above-mentioned cases represents a specific problem, but, generally speaking, they directly or indirectly contaminate the surroundings, and more specifically the communities that live in such surroundings[3].

Given that the population is exposed to glyphosate and to other pesticides, it is very difficult to establish a direct cause and effect relationship between exposure to glyphosate from aerial spraying and to differentiate it from the exposure to glyphosate and other pesticides that the population normally uses, particularly because the acute effects are similar.

In fact, in the document "Environmental Impact Caused by Chemical Substances, Illicit Crops, and Related Activities", BERNAL C, H. states, "Many of the complaints that the growers make regarding the aerial spraying carried out by the DIRAN [Antinarcotics Police] using glyphosate are actually caused by the use of farming chemicals, such as Paraquat and Parathion, which the peasants use on their crops without any technical standards and without protective equipment. Many of these substances are liposoluble, which means that they can be absorbed through the tissues and accumulate in the organism, leading to intoxication, which, in many cases, depending on the toxicological classification of the product, may be fatal" [3].

Health problems caused by exposure to these types of substances are difficult to prevent and control in our country, for several reasons: the lack of technical knowledge and infrastructure required for appropriate management, an insufficient system of monitoring and control, serious deficiencies of information and training in this area for the populations at risk, deficient medical attention and decision-making capacity of the regional agencies, and the non-existence or insufficient existence of a public health system to monitor intoxications caused by pesticides.

Faced with this situation, Colombia must study the possible effects of aerial spraying with glyphosate on the population's health. This study is designed to respond to this need.

1.2. Justification

1.2.1. Theorical Framework

Glyphosate is one of the most widely used herbicides in the world. It has been extensively tested in the United States, Colombia, and in other places and its agricultural use is accepted, recorded, and authorized in 153 countries. Since 1978 Colombia has been carrying out aerial spraying of illicit marihuana, poppy, and coca crops. To do so, a broad gamut of chemicals such as Paraquat (1978), Triclopyr (1985), and Tebuthiuron (1986) was tested, and glyphosate has been used continuously since 1993[4].

The Illicit Crop Eradication Program through Glyphosate Spraying (PECIG) is an official Government of Colombia anti-narcotics policy designed by competent authorities, which commits the executing agencies to conduct the program with minimum social impact and without producing significant harm to the environment. PECIG is a total action strategy for extensive or industrially grown illegal crops carried out by the Colombian National Police Anti-narcotics Division, and this agency must follow strict operational parameters[5].

The decision to implement the program was made by taking into account the following factors, among others: a large portion of illicit crops are industrial by nature; there are substantial difficulties accessing the plots by land or river because of isolation and due to a public order problem that obviates manual eradication; there is strong pressure on ecosystems that are strategic for Colombia; and the detrimental environmental impact caused by activities related to the illegal drug industry[5].

The national government deemed it necessary to employ controlled aerial spraying with the herbicide glyphosate as an effective mechanism for illicit crop eradication due to the national topography. Illicit plantations are located in geographical zones that are difficult to access, which considerably hinders the legitimate control that the State must exercise over them. Due to the above, in January 1992, the National Anti-narcotics Council authorized under law the controlled aerial spraying of illicit crops using glyphosate, provided that the spraying be carried out under strict control procedures and technical conditions, to ensure that it guarantee that neither persons nor natural resources in the surrounding areas would be affected[5].

The National Anti-narcotics Council set forth the legal justification, using as a foundation, among others, 1986 Law 30 1986, 1993 Law 99, 1974 Decree 2811, 1994 Decree 1753, 1991 Decree 1843 and National Anti-narcotics Council 1994 Resolution 0001 and 2000 Resolution 0005[5].

The two above-mentioned resolutions define that the responsibilities for environmental, health, and epidemiological follow-up on the Illicit Crop Eradication Program through Glyphosate Spraying (PECIG) lie with the Ministry of the Environment, the Ministry of Agriculture (ICA), and in the Ministry of Health, respectively[5].

1.2. Physical-Chemical and Toxicological Properties

Microbial degradation is the main cause of glyphosate's decomposition in plants. Loss due to photodecomposition and/or volatilization is minimal or almost null and it is reported that the average life expectancy of glyphosate in plants is up to 6O days[4].

Glyphosate is rapidly and strongly adsorbed by particles in the soil, which hinders its mobility, its lixiviation, and its ability to be adsorbed through roots. Adsorption is greater in soils with high concentrations of trivalent metals such as iron and aluminum, instead of high concentrations of sodium and calcium. The degradation or decomposition of the product in the soil is also of a micro-biological nature. One of the main products of degradation due to bacterial action is amino methyl phosphonic acid (AMPA) that is equally biodegradable. The degradation of glyphosate in the soil is rapid due to microbial action and it has an average life expectancy of approximately 3O days[4].

When it reaches water, glyphosate is adsorbed by suspended particles or in sedimentation and is later degraded; this occurs more slowly than in soils due to the lower number of microbes. Glyphosate in natural bodies of water has an average life expectancy of 7 to 10 weeks.

Toxicity in Mammals[3]

LD5O. Orally Acute: Rats: 5,6OO mg/kg
Mice: 11,3OO mg/kg

Through the Skin Acute: Rabbits: >5,OOO mg/kg

In food: NOEL (non-observable effect) in
Rats, 31 mg/kg, daily during two (2) years
Dogs, >5OO mg/kg, daily during one (1) year

Toxicity in Non-Mammals3

LD5O. Orally Acute: Common Cornish Hen: >4,64O mg/kg
Bees: >O,1 mg/bee
Contact: Bees: >O.1 mg/bee

LC5O. Cornish Hens and Ducks: >4,64O mg/kg in the food during five (5) days

Trout: 86 mg/liter (96 hours)
Bluegill (fish), 12O mg/liter (96 hours)
Daphnia (fish), >78O mg/liter (48 hours)

Glyphosate is a pesticide that is not very toxic for humans and animals, excluding the toxic degree of the solvents and other components in commercial formulas. Analyses of other types of toxicology confirm the result obtained for rats and classify the herbicide as non-carcinogenous for human beings4

1.3. Effects of Glyphosate and its Adjuvants on Health

1.3.1. Short-term Effects (Acute Intoxication)

If glyphosate is inhaled, it may cause slight irritation of the nose and throat mucosa; if there is contact with the eyes, they may become irritated, and if there is skin contact, it causes sensitivity, slight irritation, and photosensitivity[4] .

Studies done on living creatures (cows, sheep, and hens) showed that those beings absorb limited quantities of glyphosate. The allowed levels of glyphosate in crops and in animals for human consumption are published in the Federal Regulations Code, Heading 40 (40 CFR), Section 180.364. The acceptable daily amount ingested for human beings is 0.3 mg/kg[6].

Out of 194 cases reviewed in Taiwan and New Zealand, 23 of them were fatal after ingestion of variable volumes, around 114 milliliters[6].

Below is a description of the signs and symptoms for acute intoxication.

Asymptomatic: No symptoms or abnormalities detected during a physical or from lab tests.

Slight: Mainly gastrointestinal symptoms and signs (nausea, vomiting, diarrhea, abdominal pain, pain or burning in mouth and throat) that go away after a 24 hour period. Stable vital signs, no breathing, kidney or cardiovascular difficulties.

Moderate: Estimated ingestions of 20 to 500 ml produce moderate symptoms, estimated ingestions of 5 to 150 ml produce slight symptoms and estimated ingestions of 5 to 50 ml produce no symptoms. Gastointestinal symptoms that last more than 24 hours: gastrointestinal hemorrhaging, esophagitis or gastritis verified through endoscopy, mouth ulcers, hypo-tension that responds to intravenous fluids, breathing dysfunction that does not require intubation, perturbations in the acid - base balance, evidence of transitory hepatic or kidney damage or temporary oliguria.

Severe: Breathing dysfunction that requires intubation, kidney failure requiring dialysis, severe hypo-tension, cardiac failure, coma, repeated convulsions or death.

1.3.2. Effects due to Long-term (Chronic) Exposure

Carcinogenesis: Glyphosate can alter the production of carbon and nitrogen in the soil (with organic matter). An increase in the concentrations of CO2 in the soil lead to an increase of nitrifying bacteria, which in turn leads to an increase in the concentration of nitrites, making the food grown there also have greater concentrations of nitrites that combined with amines produce nitrosoamines, defined as cancerous substances. In addition, nitrites in high concentrations can produce metahemoglobinemia in animals and human beings. That is to say, glyphosate, through this mechanism, could indirectly lead to carcinogenesis and other pathologies.[4]

In the United States, glyphosate has been classified as non-cancerous for human beings. Nonetheless, the evaluating committee clarified that "this designation is based on the evidence available at the time of the evaluation and must not be interpreted as a definitive conclusion that the agent is not cancerous under any circumstance. "

Mutagenicity: Positive results have been found for mutagenesis in Soil Pseudomona sp pg2982. Glyphosate did not prove mutagenic in tests using mammal cells in in vitro and in vivo systems. There have been reports of harmful effects in human lymphosite studies that showed that glyphosate produces changes in the ADN of sister chromatides; notwithstanding, the report repeatedly stated that at least ten (1O) donors should be considered in the study and not two (2) as was done4,[7].

Effects on Reproduction: The maternal non-observable effect level(NOEL) for two (2) teratological studies using rats and rabbits was 1,OOO mg/kg/day and 165 mg/kg/day, respectively.

Teratogenesis and Embryo-toxicity: Using doses of over 3,5OO mg/kg/day of glyphosate on rats, evidence of toxicity to development was observed in the form of de-ossification of the sternum and a drop in total body weight. These doses were also toxic for the mothers. The non-observable effect level (NOEL) for development and maternal toxicity was 1,OOO mg/kg/day. In a study on reproduction made on three generations of rats using different doses, the significant toxic finding was tubular dilating in the kidneys of the first generation newborn the mothers who received the highest doses (3O mg/kg/day). The NOEL for this effect was 1O mg/kg/day[4].

The EPA has concluded that consuming crops treated with glyphosate and animals fed with forage treated with glyphosate in the US does not present food risks when the residues are under the tolerance levels. The toxicity of glyphosate depends jointly on several factors of the ecosystem and on the physiological conditions of each living organism, but in the case of using this herbicide in illicit crop eradication programs, the possibilities of contamination with significant doses would be minimum because, in practice, each illicit crop is treated only once.

In order to understand the possible effects that would be generated on organisms when sprayed from the air with glyphosate, below is an analysis of the doses applied by the program and of the time during which organisms are exposed to it[4].

After the glyphosate is aerially sprayed using a concentration of 162 g/L (16,2% P/V), a minimum 75% of it is deposited on the foliage of the illicit plants; therefore, more than approximately 342 mg/m2 is stored on this type of plant and an approximate quantity of 38 mg/m2 reaches the soil. A human being in the area being sprayed may be exposed to approximately 650.8 mg (1.93 ml) of glyphosate. The level for any risk at all is 150 ml ingested orally or 2,000 ml absorbed through the skin; given the above, we deduce that the degree of exposure to glyphosate caused by aerial spraying is insignificant for the critical levels presented for both ingestion and exposure through the skin.

Rodents have a body surface of approximately 300 cm2 and an average weight of approximately 200 g; therefore, the level of exposure for them will be 11.4 mg and the average lethal dose for this type of organism is at levels higher than 5,600 mg/kg of the rodent's weight, that is to say, for 200 g of the rodent's body weight the average dose to which it would be exposed would be 1,120 mg. Based on that, there would be no possibility that aerial spraying would affect that type of organism.

Some of the commercial formulas of glyphosate have a surfactant known as POEA, at a proportion of near 15%. According to several toxicological research studies, this compound may cause gastrointestinal damage, may affect the central nervous, may cause breathing difficulties and may be able to destroy red blood cells in human blood.

Studies also state that POEA may contain an impurity identified as 1- 4 Dioxane that has proven to have a cancerous capacity on animals and to cause liver and kidney damage to human beings.

The metabolization of glyphosateis preponderantly caused by the microflora, although the resulting metabolites are not taken advantage of by the microorganisms that originated them. In spite of the fact that aerobic and anaerobic degradation of the parental molecule gives origin to at least six (6) metabolites; those that produce most and have most importance are AMPA or Amjno methyl phosphonic acid (CH6 NO3 P) and SARCOSINE or N-Methylglycine, Sarcosine or Acid 2-Methylaminoethanoic (C3 H7 NO2). AMPA can be detected in the soil and in the tissues of the plants and its toxemic capacity is classified as inocuous[4].

During a period of time there was concern that the metabolic process of glyphosate could originate the formation of nitrosamides that are known to induce mutagenic, carcinogenic, and teratogenic effects, or certain intoxications of an acute nature. We now know that that concern was unfounded; no researcher has demonstrated or found evidence of the formation of such metabolites. Something similar occurred with the reports issued after 1990, in the sense that among the decomposition products of the parental molecule of glyphosate we must also include formaldehyde, a compound that is currently on the list of potentially carcinogenic substances; although that possibility exists, the quantities that are produced as a result of normal use in weed control tasks may possibly be of the trace levels, with very little risk for users. The degradation of the parental product may be a fast or a slow process, depending on many conditions; in some cases degradation may occur in less than one week whereas, in others, the average life expectancy may be months or even years[4].

During the document review made for the Environmental Management Plan, we found an Environmental Protection Agency (EPA) study on the analysis of glyphosate, which concluded that the appropriate use of glyphosate, as permitted in the USA, would not cause irrational adverse effects on human beings or on the environment. It is not believed that the spray program exposes human beings who may be in the sprayed fields to said risks. This is due to the fact that the potential irritation and toxicity of the independent ingredients diminishes when the product is diluted in water to make the mixture (the final product is approximately 75% water) and the mixture is dispersed during spraying. Therefore, human beings who may be located under the spray swath released by the airplane are not exposed to concentrated formula levels of glyphosate and if they have symptoms of exposure, they will be reversible and short-term. Furthermore, it is improbable that any one field would be sprayed more than once a year, which reduces the levels of repeated human exposure[4].

For our research background, we only have information on three (3) previous descriptive studies on this topic: one done by D. Revelo et al., "Effects of Fumigation Using Glyphosate on the municipalities of Valle de Guamuez, San Miguel, and Orito, Putumayo. — Colombia December 2001" in which an analysis was made of the information found in the complaint forms filed with the local community leaders in the municipalities of Valle del Guamez and San Miguel and those supplied by the Orito Technical Assistance Unit.

This study showed that 1,153 (80%) of the 1,443 complaints filed with the local community leaders in Valle del Guamuez, San Miguel, and Orito refer to health problems attributed to spraying. The above means that 4,833 persons from 131 hamlets had symptoms related to acute intoxication caused by spraying using glyphosate. The various symptoms were mentioned in the following number of times: skin rash 524, fever 516, headache 469, acute respiratory infection 454, diarrhea 373, vomiting 281, abdominal pain 221, general discomfort 179, dizziness 137, anxiety, fear, and panic 64, sore throat 41, conjunctivitis 32, and others 30.

However, the estimated percentages of change in the morbidity during the months of January and February 2000 as compared to 2001, in the La Hormiga Hospital and in the Puerto Asis Hospital, show a statistically significant increase in fever, diarrhea, abdominal pain, acute respiratory infection and skin infections with values of p<0.005[8]. This indicates an increase in sensitivity to morbidity as a factor that impels a visit to the doctor because none of the events mentioned are related to a possible significant exposure to spraying using glyphosate, except for conjunctivitis, whose cause was not reported.

The second study was done by Dr. Camilo Uribe, Director of Clinica Uribe Cualla, upon request by the United States Embassy Bogota's Narcotics Affairs Section. It consisted of a review of the complaints made by the community of Aponte, located in the northwestern area of the provincial department of Narico, during spraying in the year 2000. Out of the 29 complaints, 21 medical charts were made available by the Aponte Health Center, and in these cases the diagnosis found was illness due to an infection or to other causes not related to intoxication caused by glyphosate.

The third study, also done by Clinica de Toxicologia Uribe Cualla, was requested by the United States Embassy Bogota's Narcotics Affairs Section. It consisted of a study in municipalities in the department of Putumayo where controlled spraying using glyphosate had been carried out during the months of December 2000 and February 2001. The study observed and retrospectively measured the possible effects on human health attributable to exposure to glyphosate and the possible effects caused by exposure to other pesticides used to grow coca crops[9].

The study found that the health problems observed in the municipalities under study had prevalence rates similar to those found in the epidemiological reports from years before the spraying started. The population complained most of having gastrointestinal, skin, eye, and respiratory problems.

The health complaints were not related to the location of the persons at the time of spraying. Also, the study found that the reported symptoms may be due to the population's chronic exposure to the many farming chemical products used in the coca crops in the provincial department of Putumayo[9][10].

Moreover, there are reports of investigations of events attributed to aerial spraying using glyphosate (Botero, 2004[10]), in which the medical and epidemiological investigation of each one of them has proven that the phenomenon attributed to spraying had another cause (generally infectious) unrelated to exposure to glyphosate.

None of the studies mentioned above established a cause-effect relationship between the health problems reported and the PECIG. Many of the medical cases reported did not coincide with the dates on which spraying was done, and were reported either before or much after. The health conditions reported are compatible with the endemic conditions in these zones. Also, the studies made were retrospective, which does not enable establishing or discarding a relationship between exposure to a given substance and clinical manifestations due to such exposure.

It is important to take into account that there are studies that demonstrate that organophosphorate and carbamate pesticides can adyuvate the development of infectious illnesses, especially of the respiratory system; however, there are no exact figures available. We know that peasant workers use these toxic products indiscriminately and that most of them are at a risk and lack appropriate practices for chemical use. This suggests the possible existence of acute and chronic intoxications and the existence of a risk factor for the occurrence of infectious illnesses.


2.1. General Objective

To explore the possible effects of glyphosate on human health as a result of aerial spraying.

2.2. Specific Objectives

  • To detect possible cases of acute intoxication from pesticides concomitantly present when applying glyphosate through aerial spraying.
  • To describe the signs and symptoms of human exposure to glyphosate during aerial spraying.
  • To characterize the exposure to other pesticides to which the population in sprayed areas is subject.
  • To explore some of the population's attitudes regarding aerial spraying.



Descriptive case studies.



The population in the sprayed areas in the departments of Antioquia, Narico, and Putumayo.


In the provincial departments under study, we did not seek a statistically representative framework, for various reasons. First of all, the study does not have the scope of a scientific study that would enable establishing cause and effect relationships or making any kind of inference. Instead it is an exploratory proposal to gather and document epidemiological evidence to serve as a base for making a future decision about research. Secondly, there is a high cost implied in this type of work. It is more rational to do an initial exploration before proceeding to a study with the required methodological rigor, which represents a large investment. Thirdly, Colombia does not have the infrastructure to do the tests to determine glyphosate in biological samples so it has to resort to international laboratories. Fourthly, there are difficulties in carrying out the processes and procedures required by the regional agencies and there are ongoing problems in the municipalities due to the armed conflict (this includes most of the areas of influence of PECIG), so it was necessary to choose zones where operational conditions were the least risky.

Due to the above, we defined a sample size of up to 100 individuals to be recruited among the population in the sprayed municipalities who spontaneously go to the doctor's or who are detected through an active search during the first five days after glyphosate spraying.


Suspected Cases

All individuals who go to local hospitals, health centers or to the health brigades (MEDCAPs), complaining of signs and symptoms compatible with acute intoxication caused by pesticides.

Probable Cases

Medical cases with signs and symptoms associated with exposure to pesticides, including aerial spraying or medical cases compatible with the definition of light to severe acute intoxication.

All individuals who go to local hospitals, health centers or to the health brigades, complaining of signs and symptoms attributed to exposure to glyphosate after aerial spraying in the zone. The signs and symptoms that may be seen are:

  • Digestive symptoms: nausea, vomiting, abdominal pain, and diarrhea
  • Skin symptoms: irritated skin, pruritus, erythema, blebs, and blisters
  • Eye symptoms: reddening, conjunctival irritation, burning and conjunctival hemorrhage
  • Respiratory symptoms: cough and dysnea

Persons who file complaints with municipal administrators and ombudsmen must be passed on to a health care center for clinical evaluation.


4.1. Design of Instruments

A survey will be designed to evaluate the exposure, in which the following aspects will be taken into account:

  • Evaluation of signs and symptoms related to acute intoxication caused by pesticides
  • Toxicological history, such as if the person smokes or drinks alcohol
  • The person's demographic characteristics
  • The person's history of occupational exposure to pesticides, such as type of work, use of pesticides, time exposed, use of protection equipment, hygiene and industrial safety measures
  • Type of pesticides used
  • What the person thinks about the ICEPG
  • Results of biological tests to determine pesticide exposure.

4.2. Biological Monitoring

A urine sample and a blood sample will be taken from the 100 patients selected according to the criteria and medical evaluation included in the study. These samples must be collected within a maximum of five (5) days after the aerial spraying.

The tests to be done are listed below.

1. To Determine glyphosate and amino-methyl-phosphonic acid (AMPA) in the urine: This is done at the Quebec Toxicology Center in Canada where the gathered urine samples are sent.

2. To Analyze Some Organochlorates (OC) in Serum: This is done using fine layer chromatography. The following pesticides will be included: heptachlorox, p-p, -DDT, aldrin, chlordane-gama, oxichlordane, heptachlorox epoxide, hexachlorobencene, and p-p, -DDD. The samples will be processed in the National Health Institute Environmental Health Laboratory.

3. To Determine Acetylcholinesterase (Ache) in the Blood: The test will be done using the Lamperos and Ranta method and will be processed in the National Health Institute Environmental Health Laboratory.

 4.2.1. Procedure for Collecting Biological Samples

For each individual, take a urine sample (approximately 50 ml.) and a blood sample (10 ml). Split the blood sample as follows: 9 ml without anticoagulant, centrifuge it to determine organochlorates, and 1 ml with heparin to determine Ache.

1. To Determine glyphosate and amino-methyl-phosphonic acid (AMPA): Collect urine from one micturition (approximately 50 ml) in polypropylene containers with a screw-on cap; once you have the sample, keep it frozen (in a refrigerator) until you send it.

2. To Analyze Some Organochlorates (OC) in Serum: Collect 9 ml of blood without anticoagulant in Pyrex-type or similar hard glass test tubes. Centrifuge the samples and separate the serums placing them in a Pyrex tube or a similar one and cover the opening with aluminum foil before screwing on the cap. Keep the serums refrigerated until you send them.

3. To Determine Acetylcholinesterase (Ache) in the Blood: Place 1 ml of blood in Ependorf test tubes containing sodium heparin as an anticoagulant. Also keep these samples refrigerated until you send them.

Take the blood samples using a 10 ml disposable syringe and split it into two test tubes. Deposit 1 ml in an Ependorf test tube containing heparin and deposit 9 ml in a dry test tube and centrifuge. To transfer the blood from the syringe to the dry test tube, take off the needle and slowly press the embolus to make the blood flow against the inside wall of the test tube, to avoid hemolysis.

If you do not have a centrifuge, take the 10 ml of blood with the syringe and then deposit 1 ml in the test tube with heparin, let the sample sit during two hours in the same syringe in a vertical position, after first bending the point of the needle with pliers. Later, very carefully remove the embolus, always using surgical gloves, and with a micropipette or a syringe separate the serum and deposit it in a Pyrex test tube or in a similar one.

Label each sample test tube by writing in pencil the patient's name and an assigned code. Annex the following data: date and time the sample was collected, name of the local hospital local or health center and locality or municipality where the sample was taken. In each local hospital or health center, keep the blood samples refrigerated and the urine samples frozen until you send them to the respective Regional Health Directorate, using a messenger service that the project will pay for. When you send all of the blood and urine samples, keep them refrigerated; to do so, the project will supply special recipients (ICE PACKS); keep them frozen in a refrigerator until you use them. Send the samples in Styrofoam coolers with the lids sealed with masking tape and on the tape write down in three different places the complete name and signature of the person in charge of sending the samples.

Send all of the collected samples as quickly as possible. Blood samples when refrigerated only remain stable for five (5) days after they are taken and they must be processed within that period of time.

The project will supply all materials for taking and sending the biological samples. Therefore, do not use any other recipients.

Send all samples to the National Health Institute (INS) Environmental Health Laboratory, Avenida Calle 26 No. 51 - 60 CAN, Bogota, using the messenger service that the project has contracted.

If you have any doubts, please contact Jaime Ortiz or Marcela Varona at the INS Environmental Health Laboratory, by phone at 2207700 Ext. 448 / 449 / 450, or Gloria Lucia Henao Ext. 323 / 541; by fax at 2207700 Ext. 447, or by e-mail: mvarona@ins.gov.co, ghenao@ins.gov.co.

4.4. Methodological Procedure

4.4.1. Planning

In this stage we will carry out the following activities:

  • Design the survey to evaluate the effects of aerial spraying.
  • Review by the Ministry of Social Protection Technical Work Committee members and by the National Health Institute.
  • Adjust the survey.
  • Consult with the Territorial Health Agencies for the purpose of establishing an initial contact, to inform them of the project objective, the scope of work, to identify support activities, and to agree upon some logistics for the operation of the project, such as possible participants, places for training, etc.
  • Summons: the Ministry of Social Protection will send a letter to the Territorial Health Agency informing the importance of carrying out the project, the main activities to be carried out, and areas of influence. It will also send the municipal mayors and the respective State Social Agencies (ESE) managers a direct letter of invitation.
  • Preparation of workshops and educational material.

4.4.2. Pilot Test

This will be done at the same time as the first physician training. During the pilot test, the instrument will be tested, the pertinence of the variables suggested will be evaluated, and suggestions made will be incorporated.

4.4.3. Training

There will be a training course on diagnosis of pesticide intoxication, treatment, prevention, and surveillance for professional health personnel in the municipalities, and for health technicians, persons, and institutions related to pesticide use and handling, such as ICA Regional Offices, the Regional Autonomous Corporations, Sena, UMATAS and community leaders.

The course will last one week in each department, divided into two parts. The first part is a three-day course (Monday through Wednesday) for physicians and other health professionals; the second part is also a three-day course (Wednesday through Friday) for environmental health technicians and there is a topic in common for the two groups, relating to technical operational aspects of PECIG.

Healthcare Personnel

The objective is to improve their ability to detect, diagnose, and medically attend pesticide exposure and intoxication cases and to teach them the methodology to be used in the project.

Environmental Health Technicians

Training for this personnel is aimed at developing skills for identifying, monitoring and controlling risk situations associated with pesticide use and handling in the municipality, as well as abilities to develop case research during the public health monitoring process and to educate the community in the prevention and control of domestic risks.

Community Leaders and Municipal Ombudsmen

They will be informed on the project and their responsibility for immediately passing along to the nearest health unit for evaluation any person who goes to them to file a complaint.

4.3.2. Detecting and Selecting Subjects for the Study

Detecting the subjects for the study starts when the spraying is done. A series of resources must be mobilized at a central level and at provincial department and municipal levels, as described below.

An INS researcher must travel to accompany the persons doing the work as of the time when the spraying begins and ensure that, for each case captured, the surveyors fully complete the evaluation survey and take the biological samples under the required conditions. To do so, the Colombian National Police Anti-narcotics Division must inform the researchers the date on which spraying will be done in that project zone, with minimum two (2) weeks advance notice, for the purpose of doing travel and fieldwork logistics. The researchers are bound to keep the information on the spraying dates and sites confidential.

Basically there are two (2) strategies for collecting cases. One is passive by consulting the Health Care Provision Companies (IPS) and the State Social Agencies (ESE); the other is active by using the medical health brigades. The strategy to be used will depend on local possibilities.

The persons collected from IPS or ESE emergency service or outpatient visits, who according to the physician meet the case definition criteria, will be informed of the importance of carrying out the research project and of how they will benefit by participating in it. If they agree to participate, they will be given a consent form to sign. Then they will be given the survey and immediately thereafter samples of urine and blood will be taken for pesticide analysis. To do so, we will have the support of a bacteriologist or of a nurse, and that person will be responsible for taking, conserving, and transporting the sample and for the custody of the samples, all following the procedure set forth herein.

Whenever possible, the INS employee will take a photograph of the persons selected for the project.

All subjects with a history of exposure to pesticides who have signs and symptoms compatible with acute intoxication will be reported to the National Public Health Control System (SIVIGILA) using the individual notification form set forth in the Public Health Acute and Chronic Pesticide Intoxication Monitoring Protocol, using the information flow set up in the system. It is important to remember that confirmed cases with any of the following criteria will be entered into the system:

  • Medical / Epidemiological: When, at the moment of hearing of the case, through the patient, his/her workmates or relatives, it is possible to document a history of exposure to the toxic element, how the person was exposed, the agent, the mechanism, and when it occurred, and also when there are clear signs and symptoms of intoxication. In this situation, the lab analyses to identify the agent are not needed.


  • History of exposure to the toxic element and biological indicator of exposure or of altered effect based on the pesticide and presence or no presence of evident signs and symptoms.


  • Forensic: In case of death, confirmation using forensic procedures.

Continuing with the process, both the samples and the surveys of the subjects will be sent to the INS a maximum of five (5) days after being collected. One of the INS employee's activities during fieldwork is to supervise timely delivery; taking into account that the areas of influence of the spraying may be areas far from the capital or from cities that have airports, this person will ensure the mechanism for transporting the samples using the means available in those places. These expenses will be assumed by the project under the INS employee's supervision.

In some provincial departments, referral units will be established, as follows: in Antioquia, the Caucasia ESE and in Narico, the Tumaco ESE. These units will be the bridge for sending the samples from the municipality of origin to the Regional Health Agency. In the referral unit and in the Regional Health Agency alike, a person will be designated to be responsible for supporting the delivery of the samples. In the provincial department of Putumayo, the Puerto Asis ESE will send the samples directly to Bogota.

When cases are captured by the Health Brigades, the physician will be the person in charge of identifying the case, following the procedure described for institutional collection. The sample will be taken by the aide accompanying the brigade, who will have been previously trained in the procedure for taking samples.

This type of action requires prior planning in order to provide all of the resources needed based on the zone where the activity is carried out; the items to be planned, among others, are availability of coolers, travel time, and mechanisms for transporting the samples to the referral units.

The Regional Health Agency person responsible will make a phone call to the INS advising the number of samples sent, where they are from, the date, and the airway bill number. Once they are received by INS, each Styrofoam cooler will be reviewed in order to check that it is duly sealed. It is important to clarify that any Styrofoam cooler that comes in open or whose masking tape is torn will be rejected and the person responsible in the place that it came from will be advised because this situation does not guarantee the validity of the samples taken.

The samples will be listed on a previously designed format and will be separated. The blood samples will stay at the INS Environmental Health Laboratory to be processed. The urine samples will be repacked in Styrofoam coolers; the ICE PACKS will be changed and the coolers will be sealed with masking tape, writing down on three (3) different spots of the tape the complete name and the signature of the person in charge of following this procedure. Then, the Styrofoam coolers will be packed in cardboard boxes, will be sealed and labeled, and will be transported to the messenger service office at El Dorado International Airport to be remitted to the Quebec Toxicology Center in Canada.

The Quebec Toxicology Center will report the results of the tests to the INS approximately ten (10) days after they are received, by fax, e-mail, and certified mail. Determinations of organochlorate pesticides and of ACHE will be processed as the samples are received. The results will be recorded on the survey and attached to the original documents.

During the time they are not working in the field, the researchers will carry out the activities related to data analysis. Such activities are listed below.

  • Create the database in epi-info.
  • Systemize the survey data.
  • Analyze the data as the provincial departments are covered.
  • Prepare and present partial reports by provincial department.
  • Prepare the technical standards manual for the detection and handling of acute intoxications and appropriate sample taking to determine pesticides including glyphosate in biological samples.
  • Prepare the final report.
  • Prepare the presentation of the results.
  • Coordinate the strategy to present the results.

4.3. Information Treatment and Analysis

A database will be created in the epi-info program version 6.04 to perform the uni-variegated and bi-variegated analysis of the epidemiologically important variables. The ratio measurement scale variables will be described using ratio calculation.

The uni-variegated analysis will make a description of the surveyed individuals characteristics, taking into account subject variables (composition by age and gender, distribution by type of affiliation to the SGSSS, occupation, occupational status, and unemployment and education, place of origin, etc...). A characterization of the exposure to aerial spraying and pesticides in general will be done as well as of the related medical history. The social problem of displacement, the main migration sites and the motivations associated will be analyzed. In addition, some perceptions of the persons regarding PECIG will be analyzed.

The bi-variegated analysis will cross-reference the main variables that characterize the exposure and the biological monitoring results.

For the purposes of the analysis, the cases studied will be classified into the following three categories:

  • Positive case for glyphosate biological marker
  • Positive case for other pesticide biological markers
  • Negative case for biological markers.

4.4. Inclusion and Exclusion Criteria

4.4.1. Inclusion Criteria

All of the individuals who meet the following criteria defined exclusively by the physician will be included in the project.

  1. Individual with signs and symptoms of exposure to pesticides.
  2. The exposure must be related to aerial spraying in the zone.
  3. The person goes to the physician maximum five (5) days after the spraying.
  4. The patient voluntarily accepts to participate in the study.
  5. The patient agrees to a urine sample and a blood sample.

4.4.2. Exclusion Criteria

  • Those individuals who file a complaint and whose exposure has occurred in a municipality in a provincial department other than the provincial departments included in the project.


  • All individuals whose biological samples cannot be taken or who did not visit the physician maximum five (5) days after spraying in the zone, in spite of the fact that they have signs and symptoms.


  • Those individuals selected for the study whose samples could not be sent maximum five (5) days after taking them, for whatever reason.


  • All individuals who do not wish to participate voluntarily.


  • All subjects whose samples arrive at INS in coolers that are open or that have the masking tape torn or samples that have lost their contents due to bad packing.

4.5. Impact Expected with the Use of the Results

  • We believe that the results of this study will enable us to make a first attempt at explaining the possible effects that the glyphosate used in the ICEPG may have on health.

In the event exposure risks are found, we will:

  • Make suggestions that eliminate or diminish the levels of pesticide exposure of the groups at risk.


  • Recommend prevention and control actions and integrate the different healthcare institutions for the pesticide intoxication occurrence notification process.


  • Adopt legal provisions to contribute to diminishing or eliminating the risks.

4.6. Ethical Considerations

Before starting to gather the information and the samples, the persons in charge of taking the survey will inform the subjects regarding the objectives of the contingency plan that will be carried out, its importance and the benefits that they will obtain from participating. They will be given a consent form that they must sign before answering the questions in the survey and before having the biological samples taken.


  • The procedure for applying the method and the times established for performing the biological monitoring after the spraying are strict. The time for taking the samples for biological monitoring must be a maximum of five (5) days after the exposure.


  • Conditions of public order in the zones under the PECIG may interfere with the study.


  • The proposal does not include evaluating the chronic effects of glyphosate.


  • It does not replace the routine monitoring system that must exist for the follow-up of the possible pesticide intoxication cases and does not offer an answer to all of the complaints filed by the community.


The initial budget assigned to the National Health Institute by the Ministry of Social Protection is 200,000,000 Colombian Pesos.


Defined throughout 2003 and 2004, based on the Colombian National Police Anti-narcotics Division (DIRAN) spraying activity schedule.



[1] URIBE, S., Project on Colombian Coca Plantation Yields, Progress Report #5. October 25, 1999.

[2] ARCILA, N. O., RODRIGUEZ, S. A., Case Study of Coca Production in the Provincial Department of Guaviare. AMAZON SCIENTIFIC RESEARCH INSTITUTE (SINCHI). Human Settlement Area, Bogota, September 1997.

[3] BERNAL C, H. Environmental Impact Caused by Chemical Substances, Illicit Crops, and Related Activities. Chapter I. DNE Research and Strategic Subdivision.

[4] Ministerio de Salud e Instituto Nacional de Salud, eds: Informacion sobre Glyphosate. Uso y Toxicologia. Boletin No. 1. Febrero de 1992.

[5] Direccion Nacional de Estupefacientes -DNE-. http://www.cultivosilicitoscolombia.gov.co. En historia cultivos ilicitos.pdf

[6] Worthing C. R., Hance R. J., eds: The Pesticide Manual. The British Crop Protection Council, 9th Edition, 1991; 459- 46O.

[7] Grossbard E., Atkinson D., eds: The Herbicide Glyphosate. Butterworths, 1985; 127-131.

[8] REVELO C., D. Putumayo Provincial Department Health Secretariat - Public Health Subdivision.

[9] "Uribe Cualla" Toxicology Clinic. "Alleged Effects of Glyphosate on Human Health", technical document 2001.

[10] Botero, Jorge H., "Review of Populations' Exposure to Glyphosate under the Illicit Crop Eradication Program and Review of Complaints regarding the Effects on Human Health", Unpublished Report, Narcotics Affairs Section, Embassy of the United States of America, Bogota, DC, 2004