Introduction
The use of pesticides in agriculture is a common practice after World War II (Chambers et al., 2001). Its intensive application in agriculture causes negative effects on human health, and environmental pollution (Arias et al., 2008; Mackinlay, 2008). The World Health Organization estimates that about 3 million cases of acute poisoning occur each year due to the unsafe use and handling of pesticides with 220,000 deaths (Blair et al., 2014; WHO/UNEP, 1990); 70 % of these deaths are due to occupational exposure (Yerena et al., 2005). Here, it is necessary to clarify that occupational exposure to pesticides is understood as the level of contact (direct or indirect) and the frequency that a group of people presents due to their working conditions during the production, transportation, preparation, and application of pesticides (Damalas & Eleftherohorinos, 2011; Maroni et al., 2006), which has a close relationship with the toxicological level (Hoppin et al., 2006) rates the level risk to a large extent.
There is a vast literature on occupational exposure to pesticides in developed countries, but it is a subject that remains partially ignored or poorly studied in developing countries (Atreya, 2007, Imran & Dilshad, 2011), despite being one of the greatest occupational hazards of intoxication among farmers. In fact, the presence of pesticides in the work environment constitutes a potential risk of exposure (Alavanja et al., 2013; Butinof et al., 2015). The determination of the level of occupational exposure to pesticides in rural areas presents various difficulties, due to the irregular use of pesticides and variations in their forms of use (Tielemans et al., 2007). According to official figures, the use of insecticides was 37x103 t and 31x103 t of herbicides in Mexico in 2013 (FAO, 2014), and the states with the highest volume of agrochemical commercialization were Michoacán, Jalisco, Veracruz, Sinaloa, Puebla, Guanajuato, and Chiapas (INEGI, 2014). Unfortunately, cases of acute pesticide poisoning do not reflect the real magnitude of the problem, since there is an under-registration in national statistics (Henao & Nieto, 2002; Albert, 2006). The determination of occupational exposure is one of the greatest challenges in the study of the relationship between pesticides and human health (Maroni et al., 2000; Baker et al., 2005). As a matter of fact, the application of appropriate instruments is a challenge to build a methodological tool that allows the identification of social-labor profiles of workers at occupational risk. In addition, it helps to identify the risk factors linked to the conditions of use and occupational exposure of pesticides by farmers or field workers in order to develop effective protection measures (Lantieri et al., 2009).
This study pointed out the importance of sugarcane as the most cultivated crop worldwide (Senties-Herrera et al., 2014) and the main industrial crop in Mexico. It is cultivated and industrialized in 15 states, and the state of Veracruz is the main producer (SAGARPA, 2013). The value of the national primary production of this crop is $ 28x109 M.N. and more than 165,000 farmers are involved in this activity and a number of day laborers has not been accounted yet (Aguilar-Rivera et al., 2012).
The aim of this study was to characterize the occupational exposure to pesticides among sugarcane growers and applicators, and to analyze the presence or absence of health symptoms associated with acute exposure in the Irrigation District 035, La Antigua, Veracruz, located in the central region of Gulf of Mexico.
Materials and Methods
Experimental field
This study was conducted in three municipalities of the Irrigation District 035 in the Hydrological Central Gulf-Region, Veracruz, Mexico. The selection of municipalities, according to importance and representativeness in the sugarcane crop were Actopan, Paso de Ovejas, and Ursulo Galván, located at an altitude between 24 and 175 masl, which occupy a planted area of sugarcane of 17,401 has.
Questionnaire
A structured questionnaire was designed with the following sections: 1) Demographic and occupational characteristics of the interviewees, 2) common pesticides for use or application, 3) criteria in the decision making for the selection and purchase of pesticides by the farmers, 4) practices in the preparation and application of pesticides and use of personal protective equipment (PPE), 5) hygiene habits after the application, disposal and final destination of empty containers, 6) family medical history, and 7) report of the events related to pesticide poisoning and symptom records. The questionnaire consisted of 156 questions.
Inclusion criteria
Three categories of interviewees were defined: 1) producers (P), men of legal age (≥18 years), owners of at least one sugarcane plot who do not apply pesticides in their plot; 2) producers-applicators (PA), men of legal age owners of at least one sugarcane plot who applied pesticides in their plot and who eventually work applying pesticides in other sugarcane plots, and 3) applicators (A), men of legal age who were not owners of sugarcane plantation and whose main activity was the application of pesticides in sugarcane plots.
The individuals
A total of 147 individuals were recruited for interview in this study. To obtain the sample size, the formula by Scheaffer et al. (1987) was used for a population size of 3,480 registered producers in the Irrigation Module II-1 Actopan from the Irrigation District 035, La Antigua, Veracruz (DR035). The estimated sample consisted of 345 individuals. However, during the interviews the saturation point was reached (Hernández-Carrera, 2014) and the sample size was re-estimated at 147, distributed in 74 producers, 35 producer-applicators, and 38 applicators, selected by the “snowball” technique. The key informants were the technicians from the DR035 irrigation office. Prior to conducting the survey, all participants were explained the purpose of the study and their consent was requested.
Analysis of the information
The information was recorded in an Excel database and the statistical analyzes were done using the Statistica V7.0 program. To measure the level of occupational exposure, the Pesticide Use Quality Index (QPUI) was constructed as follows: a specific and weighted rating was assigned, designated by experts in the field, to each of the answers given by the interviewees, and qualified with respect to the best practice (DOF, 1999; FAO, 2006; DOF, 2008) and the toxicity of the pesticide. For each question, the best practice received the highest score and the least appropriate practice the lowest score. The least suitable practice of each question was assigned a grade of 1 and depending on the number of answers to each question, the best practice could reach the values from 2 to 5. The average score obtained by each interviewee made up the QPUI (scale from 0 to 10), where the best practices of use or lower occupational exposure had the highest value of QPUI:
QPUI= (Grade Question 1 + Grade Question 2 + … + Grade Question n) / n
Where the QPUI is the scoring of each one of the questions included in the questionnaire and applied to the producer-applicators and applicators, and n is the total number of questions. We performed a qualitative analysis of demographic data, a qualitative analysis of nominal and a quantitative analysis of variables, and linear correlations of numerical variables. A confidence level of 0.05 probability was employed.
Results
A total of 147 individuals was interviewed, where 50 % were producers, 24 % producers-applicators, and 26 % applicators of pesticides. Table 1 provides the demographic characteristics of these interviewees.
Characteristics | Producer (N = 74) |
Producer-Applicator (N = 35) |
Applicator (N = 38) |
---|---|---|---|
Gender | Men | Men | Men |
Age in years | 57 ± 0.16* | 51.7 ± 0.28 | 37 ± 0.29 |
Maximum schooling in years | 5.5 ± 0.05 | 5.2 ± 0.09 | 7.01 ± 0.1 |
Surface with cane (ha) | 4.31 ± 0.04 | 3.33 ± 0.05. | NA |
Alcohol users [n, (%)] | 40 (54 %) | 15 (42.85 %) | 28 (73.68 %) |
Smokers [n (%)] | 10 (13.51 %) | 7 (20 %) | 7 (18.4 %) |
Total area with sugarcane (ha) | 5.29 ± 0.04 | 3.85 ± 0.06 | One applicator with 0.8 ha and two with 4 ha |
*Mean ± Standard deviation.
Pesticide selection practices
The selection criteria for herbicides and insecticides are presented in Table 2. 81.6 % of producers choose the pesticides to apply according to the effectiveness from previous years; 16.5 % call upon a specialist technician; and 1.83 % read the labels of the products before purchasing them to make a choice. To know if the product they want to apply will effectively control the pests of their crop, 49.5 % of producers take advantage of their experience, since the pests are the same.
Question | Producers interviewed (N = 109) [n (%)] |
---|---|
How do you get to know by yourself if the pesticide of your interest is suitable for the crop? | |
Because the label says it. | 1 (0.92) |
Because the technicians, supervisors, specialists and/or sellers say it | 42 (38.53) |
Because other Producers say it | 9 (8.25) |
Because it is used every year | 57 (52.3) |
How do you know if the pesticide is suitable for the pest you wish to fight? | |
Some specialist tells me what product I should buy, depending on the pest in my crop | 43 (39.44) |
It is indicated on the label for the pest I want to fight | 8 (7.33) |
It is based on the experience and each cycle is the same | 54 (49.54) |
All of them work the same | 4 (3.66) |
How do you decide a need for mixing? | |
I do not mix products | 11 (10.9) |
I ask the technician of the mill, the selling house, or another specialist in the area | 17 (15.60) |
Check on the label the mixtures allowed for each product | 4 (3.70) |
According to the other people’s experience and mine | 76 (69.7) |
All products can be mixed | 1 (0.92) |
How do you choose the product dose per hectare? | |
According to the label | 29 (26.6) |
According to the technician of the mill or the seller of the agrochemical brand | 15 (13.76) |
According to my own experience | 62 (56.88) |
According to what other Producers recommend | 3 (2.75) |
How do you choose the number of applications per cycle? | |
When I consider there is a lot of pest | 101 (92.66) |
There is a stablished calendar with dates of application | 8 (7.34) |
Where do you store the new pesticides? | |
Cellar | 79 (72.47) |
Yard or external bathroom | 21 (19.26) |
Inside the house | 9 (8.25) |
Do you investigate reentry time to the plot? | |
On the label | 3 (2.75) |
The specialists (technicians, salesmen) tell us | 3 (2.75) |
Ask another producer | 1 (0.91) |
Do not investigate | 102 (93.57) |
The majority of the producer-applicators were local property owners (ejidatarios) with 1 to 5 ha of sugarcane, they apply the pesticides by themselves in their own plot and do not hire day laborers. Only three (8.57 %) have more than 5 ha of sugarcane and six (17.14 %) from 1 to 3 ha assigned to another crop. Of the producers, 54 (72.97 %) are ejidatarios; 23 out of these (31.08 %) have land assigned to other crops and 26 (35.13 %) are older adults between 60 and 80 years old, who have gradually given up the management of cane cultivation to some son or son-in-law.
100 % of respondents apply insecticides and herbicides (Table 3) not approved for use in European Union countries. These agrochemicals are: carbofuran, carbosulfan, monocrotophos, ametryne, 2,4-D, MSMA, paraquat, diuron and picloram (Lewis et al., 2016).
Applied pesticide | Producers [n (%)] | Toxicological category |
---|---|---|
Carbofuran | 109 (100) | II |
Monochrotophos | 44 (40.7) | I |
Cypermethrine | 7 (6.4) | III |
Thiametoxam + λ-cyhalothrin | 2 (1.83) | IV y III |
Endosulfan | 2 (1.83) | II |
Glyphosate | 100 (91.74) | IV |
2,4-D + ametryne | 87 (79.81) | III |
2,4-D | 51 (46.78) | III |
Ametryn + atrazine | 57 (52.29) | III, IV |
MSMA | 61 (55.96) | III |
Paraquat | 8 (7.33) | II |
*Toxicological classification: Ia (Extremely toxic), IIb (Highly toxic), III (Moderately toxic) and IV (unlikely to present acute risk) (OMS, 2009).
Pesticide application practices
Table 4 shows pesticide application practices by type of interviewee. The preparation, both of insecticides and herbicides, is similar in all cases. Plastic tanks of 200 L are used and sold in commercial houses or recycled tanks distributors. The dose of the agrochemicals varies according to the criterion of the producer, from one to three tanks per hectare. 55.9 % of the producers said they prepared their pesticides using one or two “measures” of product, without specifying the volume or amount corresponding to these measures. They said using a empty can of “chiles” as a scoop (from 90 to 220 g), as well as disposable cups or “glasses” when they prepare less than 200 L of product (dose for a 20 L backpack sprayer), mainly during the application of herbicides or insecticides.
Variable | Interviewed Producers [n (%)] |
---|---|
Schedule of the application | |
From 6 am | 142 (96.59) |
After 5 pm | 1 (0.68) |
From 6 am to 1 pm and from 4 to 6 pm | 4 (2.72) |
Duration of the working day | |
4 h | 122 (82.28) |
6 h | 21 (14.28) |
8 h | 4 (2.72) |
Companions during the application | |
Supervisor who helps me in case of an accident | 4 (2.72) |
Assistant | 113 (76.87) |
On my own | 30 (20.4) |
Use of Personal Protective Equipment (EPP1) | |
Boot or closed shoe/hat or cap | 147 (100) |
Long-sleeve shirt | 143 (97.27) |
Mask, face dust mask or bandana | 48 (32.65) |
Gloves | 34 (23.12) |
Dorsal protection, usually with a plastic | 38 (25.85) |
Frontal protection, usually with a plastic | 29 (18.72) |
Smoke during the application | |
Yes | 11 (7.48) |
No | 136 (92.51) |
Eat and/or drink liquids during the application | |
When work is over and neat | 66 (44.89) |
I pause and wash my hands | 54 (36.73) |
When I finish, but I do not wash my hands | 5 (3.40) |
I do not eat, but I drink liquids while I am applying if thirsty | 22 (14.96) |
Post-application hygiene | |
Take a bath at the plot and a change of clean clothing | 1 (0.68) |
A change of clothing at the plot, but a bath at home | 14 (9.52) |
A bath at home and a change of clothing after application | 83 (56.46) |
A change of clothing after application at home, but a bath until night | 40 (27.21) |
A bath and a change of clothing until the night | 9 (6.12) |
Triple washing of empty containers | |
Triple washing and drilling | 52 (35.37) |
Triple washing and no drilling | 75 (51.02) |
Unwashed and discarded | 19 (12.92) |
Unwashed and reused | 1 (0.68) |
Destination of empty containers | |
Collection center | 18 (12.24) |
Dump | 13 (8.84) |
They are left in the plot | 115 (78.23) |
They are buried in the plot | 1 (0.68) |
With poisoning symptoms | 77 (52.38) |
By its acronym in Spanish.
Ninety six percent indicated that the application is made between 6 and 10 o’clock, during the cooler and less windy hours of the day which facilitates the application. Only 2.7 % of producers said they were accompanied by a friend or family member who does not participate in the application, so that they can help them in case of poisoning.
There is a lack of use of complete personal protective equipment, as it is described in the International Code of Conduct on the Distribution and Use of Pesticides (FAO, 2006) and NOM-017-STPS-2008 (DOF, 2008). It was found that more than 90 % of the interviewees wear trousers, a long-sleeved shirt and a hat when applying pesticides. They stated that they are used to do it this way and to protect themselves from the edges of the cane leaf, since it can cut their skin. This same comment was made by those interviewed who use a bandana or face dust mask (32.65 %). The interviewees who use dorsal protection (25.85 %) correspond to 20 % of the producers and 31 % of the applicators; those that use frontal protection (18.72 %) correspond to 15 % of producers and 25 % of applicators.
Presence of acute poisoning symptoms
Respondents (52.38 % of the interviewees) presented symptoms of acute intoxication during the application of pesticides (Figure 1), since 29 % are producers, 60 % producer-applicators, and 63 % applicators. In other words, the risk of poisoning is greater when there is more exposure to pesticides.
Pesticide use quality index (QPUI)
The QPUI showed significant statistical differences in the three studied groups (Figure 1), being higher in the group of applicators with a score of 7.39, and with a value of 6.84 for producers and 6.88 for producers-applicators. Table 5 shows the correlations of the numerical variables evaluated.
ED. | ESC. | A. PROD. | A. APLIC. | F. M. L.Y PANT. |
F. B. | F. S/G | F. M/ C/P |
F. G. | F. PD. | F. PF. | F. LE. | N. S. | QPUI | |
ED. | 1 | -0.6 | 0.69 | -0.14 | -0.09 | -0.15 | -0.12 | 0.07 | -0.13 | 0.04 | 0.01 | -0.09 | -0.22 | -0.22 |
ESC. | 1 | -0.27 | -0.1 | 0.06 | 0.09 | 0.14 | -0.01 | 0.16 | 0.08 | 0.08 | 0.19 | 0.14 | 0.21 | |
A. PROD | 1 | -0.47 | -0.06 | -0.03 | -0.03 | 0 | -0.16 | -0.04 | -0.03 | 0.01 | -0.15 | -0.33 | ||
A. APLIC. | 1 | 0.12 | 0.13 | 0.07 | -0.08 | 0.13 | 0.14 | -0.01 | -0.05 | 0.1 | 0.18 | |||
F. M. L. Y. PANT. | 1 | 0.72 | 0.77 | 0.07 | 0.14 | 0.08 | 0.14 | 0.01 | 0.13 | 0.23 | ||||
F. B. | 1 | 0.79 | -0.01 | 0.11 | 0.05 | 0.13 | -0.07 | 0.12 | 0.26 | |||||
F. S/G | 1 | 0.09 | 0.07 | 0.01 | 0.1 | 0.03 | 0.14 | 0.2 | ||||||
F. M/C/P | 1 | 0.33 | 0.29 | 0.39 | 0.1 | 0.05 | 0.17 | |||||||
F. G. | 1 | 0.36 | 0.3 | 0.13 | 0.13 | 0.21 | ||||||||
F. P.D. | 1 | 0.71 | 0.08 | 0.08 | 0.35 | |||||||||
F. P.F. | 1 | 0.09 | 0.14 | 0.33 | ||||||||||
F. LE. | 1 | 0.02 | -0.02 | |||||||||||
N. S. | 1 | 0.1 | ||||||||||||
QPUI | 1 |
Correlations. The marked correlations are significant to p<0.05, N=14
ED.: age (years), ESC: schooling (years), A. PROD .: seniority as producer (years), A. APLIC .: seniority as an applicator (years), FML AND PANT: frequency of use of long sleeves and trousers, FB: frequency of use of neoprene boot, FS / G: frequency of use of hat or cap, F. M / C / P: frequency of use of face dust mask, masks or bandanas, FG: frequency of use of gloves , F. PD.: frequency of use of dorsal protection, F. PF .: frequency of use of frontal protection, F. LE.: frequency of reading the label, NS: number of symptoms presented.
The two variables correlated with the highest QPUI were age (-0.22) and schooling (0.21), at older age, lower QPUI and at higher schooling, higher QPUI. The group of applicants were 37 years old as an average age, the elementary education level plus one year of middle school. On the other hand, the producers and producers-applicators had an average age of 57 and 51.7 years respectively, and an incomplete basic education.
The QPUI had significant correlations with seniority as a producer (-0.33) and as an applicator (0.18). The more seniority or experience as a producer, the lower the QPUI; and the older the applicator, the greater the QPUI. In other words, regardless the years of experience, it does not lead to better pesticide use practices. There was no significant correlation between the QPUI and the number of symptoms presented (0.1). The frequency of label reading correlated positively with the level of instruction of the interviewees (0.19).
Discussion
The sugar mill technicians carry out and supervise the control of pests in sugarcane plantations, sometimes with the authorization of the producers. For example, they are responsible for the annual control of the spittlebug or froghopper (Aeneolamia spp. and Prosapia spp.), stem borers (Diatraea saccharalis F., Diatraea magnifactella Dyar and Eoreuma loftini Dyar) and rodents (Sigmodon toltecus (Saussure) and Oryzomys couesi (Alston)) (Aguilar-Rivera et al., 2012; Peppers & Bradley, 2000; Senties-Herrera et al., 2014). On the other hand, producers are responsible for the control of weeds, although they eventually control the pests mentioned above or others if they consider it necessary. According to Senties-Herrera et al. (2014), the agroindustry of sugarcane represents the functioning of the socioeconomic system with the most tradition and roots, since the triumph of the Mexican Revolution. The results of this study show that, certainly, the management of this crop is based on traditions, on a production system in transition, where pesticides, insecticides, herbicides and fertilizers are applied more and more.
The selection process of pesticides is mainly based on the experience that the producer has gained, with records in his mind about the effectiveness of the product or in a learning process, and intergenerational experience (Table 2). The producer determines the pesticide products, the doses, the periodicity and the form of application. The interviewees mentioned statements like “We all do the same here”, “The products are the same, year after year” or “He (referring to another farmer) and I, and all of us here, apply the same thing”, “Since the sugarcane came in here, we use the same products, I have them on my notebook, it was my dad’s and now I use it”, “The only thing that changed is the name but the product, people say that the substance is the same”.
It was found that the use of PPE during the application of pesticides is minimal and incomplete. This low rate of EPP use is also reported in other studies (Waichman et al., 2007; Butinof et al., 2015). This is a warning of exposure to pesticides and a risk of intoxication. The reasons given by producers for the scarce use of PPE were: lack of habit, discomfort due to heat and its cost (Wilson & Tisdell, 2001; Cole et al., 2002; Isin & Yildirim, 2007). Although 93.87 % of the interviewees change their clothes at the end of the application, either on the plot or at home, the general custom is not to wash the working clothes during the days of the application of pesticides. Pants, shirt and boots are left in the sun to dry and reused the following days without washing them up.
35.37 % of those interviewed follow the directions of triple washing and perforation of those empty containers, as described in NOM-003-STPS-1999 (DOF, 1999); only 12.24 % take the empty containers to the collection centers of the Campo Limpio (Clean Field) a federal program, which have been installed in different localities in the area. 13 % of the interviewees discard the unwashed containers, and 78 % leave them in the plot, where they are burned during the harvest or deposited them in a corner or edge of the plot. In short, producers do not have the standard information to ensure the safe use or disposal of the pesticide containers.
The symptoms of acute intoxication mentioned were: burning and/or itching of the skin; burns and/or hives; itching, burning and dry mucous membranes; dizziness,
nausea and/or vomiting; stomach cramps, diarrhea, headache, nervousness and altered reflexes; drowsiness, sweating, chills, blurred vision, numbness and/or tongue ecchymosis; weakness and loss of knowledge. It is noteworthy that 52 % of the interviewees manifested at least one of these symptoms, 3.4 % presented fainting or loss of consciousness and were taken to the community health clinic. The low rate of medical attention shows an under-registration of cases on intoxication, which has been previously documented (Cortés-Genchi et al., 2008). Several studies report the negative health effects associated with occupational exposure to pesticides, including: dermatological, gastrointestinal, neurological, carcinogenic, respiratory, reproductive and endocrine effects (Alewu & Nosiri, 2011; Thakur et al., 2014). Some recurring statements referred to producers’ perception of susceptibility to pesticides and the generation of “resistance” among the exposed population are: “They (referring to pests) become resistant and we do the same”, “It kind of affects at the beginning, but as time goes by the body gets used to it”, “Whoever is allergic gets allergies, and whoever is not will not get it”, “If it is going to affect me no matter what I do is OK, because I am already affected”.
Isin & Yildirim (2007) reported that it is not enough for producers to know about the damage to human health by pesticides to change their behavior, since their main concern is the pest attack and, consequently, the loss of yield and lower income.
The high incidence of symptoms of acute intoxication in applicators has been documented in Mexico (Durán-Nah & Colli-Quintal, 2000; Hernández-González et al., 2007). Statistics from Central America indicate that 3 % of agricultural workers exposed to pesticides suffer acute intoxication each year (Fernández et al., 2010). In this study, 30 % reported intoxication at least once in their working life and 14 % went to the doctor for a prescription. 23 % indicated at least one symptom related to exposure to pesticides. The high frequency of symptoms in applicators and producer-applicators, evidences a greater degree of exposure in these two groups, in relation to producers (Figure 1), who normally pay for this type of work to be carried out.
No correlation was found between exposure to pesticides and long-term effects; it might be due to the low frequency of attendance to the health centers even with acute poisoning symptoms, which makes their follow-up difficult.
Gesesew et al. (2016) concludes that the high probability of pesticide poisoning in Ethiopian producers is due to both the unsafe use of pesticides and the lack of use of Personal Protective Equipment. Atreya (2008), on the use of pesticides in Nepal, concludes that the population of applicators has a high risk of exposure due to their low level of training. As pointed out by Abhilash & Singh (2009), the application of pesticides is unsafe due to the lack of training of producers and applicators, the low degree of schooling, the ignorance about their potential risks, incorrect application practices, the measurement of the dose with their own scales, the extended working day, smoking and eating during the application, the lack of PPE, mainly boots, gloves and glasses or face dust mask, and the lack of facilities to perform postexposure hygiene, the inadequate storage and disposal of containers, the lack of adequate medical services, as well as the misunderstanding about poisoning symptoms with common diseases.
Conclusions
The level of education has a direct and close relationship with the correct use of pesticides. Producers have a tendency to make their own dosage scales due to their low training in the proper use of pesticides and their little knowledge of the risks to their health and the environment. A formal training program in the use of pesticides by sugar mills or sugarcane organizations is needed. The field technicians make weekly tours to the local properties and make recommendations concerning the type of product to be applied, but not about the standard information to ensure the safe use of agrochemicals. Individuals with much greater risk of occupational exposure are those who are exclusively dedicated to the application of pesticides. Finally, occupational exposure to insecticides in sugarcane and its risk to human health is relatively high due to the lack of training in the handling and application of pesticides, and a minimal and incomplete protective clothing, which is reused without a washing up.