The types of pesticides that cause variable degree of toxicity and ototoxicity to humans are organophosphates and pyrethroids

In Brazil, the amount of pesticides consumed doubled in the last 10 years, thus, in 2008 Brazil assumed the lead position in the world. In 2011, the country used over 852.8 million liters of pesticide . Its indiscriminate application in agriculture without the use of the necessary care has contributed to environmental degradation and increased occupational exposures making it a serious health problem in the country. According to the data of the National System of Toxic-Pharmacological Information  in 2010, there were 10,269 cases of pesticide poisoning in general, of which, 1,347 were caused by occupational circumstances. It is observed that there is a large underreporting of adverse effects, especially longterm, which can determine chronic diseases.Chronic exposures to these pesticides affect the auditory system at the central and peripheral levels, regardless of exposures concomitant to noise . Ototoxicity can be defined as the result of the action of certain chemicals that injure the anterior/posterior maze, leading to auditory loss with or without vertigo, nausea and gait instability, and should be studied and considered as a public health problem . The auditory loss caused by pesticides may occur insidiously or not and its severity will depend on factors such as the amount, the time of exposure and the interaction with the ototoxic agent. Usually this loss occurs symmetrically bilateral. The symptoms resulting in vestibular alterations are dizziness and vertigo, which may appear early and more intensely than the auditory . In Brazil there are few studies that report the association between exposure to pesticides and auditory alterations, but all authors concord with the relationship . Studies made a comparison between exposure to pesticides and noise with hearing loss, and most came to the conclusion that there is evidence that chemicals can lead to hearing loss regardless of the presence of noise . 

Minas Gerais is one of the largest producers of coffee in Brazil . Research conducted involving farmers in the state showed that most use organophosphates and pyrethoids . In the region of Caratinga, located in east Minas Gerais, studies indicate the use of more than 39 types of pesticides in tomato culture , being mostly the chemical class of organophosphates and pyrethroids  Piedade de Caratinga County, located in east Minas Gerais relies on agriculture as one of the main economic activities, coffee being the most anticipated,hydroponic gutter and in the dry season the coffee producers become olericulture . Because this region is predominantly agricultural with extensive use of pesticides, especially organophosphates and pyrethroids, both in cultivation of coffee and tomato, this study sought to evaluate the auditory health and risk factors in rural workers exposed to pesticides in Piedade de Caratinga County, MG, and chart their socioeconomic profile and lifestyle, while identifying the types of crops and the use and management of pesticides.First, This is a descriptive and exploratory research with quantitative and qualitative approach to the “basic purpose to develop, clarify and modify concepts and ideas for the design of further approaches” . The study was conducted from January to June 2013, in the rural area of the municipality of Piedade de Caratingalocated in east Minas Gerais, in the middle region Vale do Rio Doce, belonging to the micro-region of Caratinga—Minas Gerais. It has a land area of 42,5127.96 mi2, population of 7,110 inhabitants, altitude 874.89 yds., average temperature of 68˚F in winter and 84.2˚F in the summer. The topography is smooth and the street layout is in bottom of the valley. Coffee production is the main economic activity due to the altitude and mild climate. During the dry season of these products, the producers become olericultures, that follow to the municipalities in the region and Belo Horizonte . Rural workers, whose main activity is spraying pesticides in cultures and who attended the audiometric examination beyond the delivery of the questionnaire and explained signed informed consents, were selected. Exclusion criteria have the use of heavy machines that emit noises, changes in meatoscopy and age above 50 years. Thus, the final sample was selected as a matter of convenience and had 23 men, rural workers, who fulfilled the principle of inclusion and exclusion established. The absence of women in the study sample was not criterion of intentional exclusion of the authors of this research. But an absence of this kind was justified by the fact that, when determining the sample was intended to initially work with the number of rural workers who were representative for the population of these rural areas under study. However, when making contact with the owners of larger farms, they did not allow the development of the project.

We then decided to work with small farmers who were self-employed, and whose women did not participate in the work with the crop, and were responsible for animal care and the home. The audiometric tests were performed in acoustic cabins, using clinical audiometer BETA 6000 – Beta Medical, calibrated according to standard methods. The professional responsible for them was a properly qualified speech therapist and registered in its class organ. In testing the therapist had no prior knowledge of the type of previous exposure of each individual. The audiogram of each rural worker was issued under ASHA . A semi-structured interview was conducted using questionnaires adapted from the study of Kos , in which data were obtained on socioeconomic and lifestyle profile, types of crops, use and management of pesticidesauditory signs and clinical symptoms. The following information was considered: age, gender, education level, monthly income, smoking and alcohol consumption. In relation to the types of crops, the data of the use and management of pesticides was collected about working hours, daily working periods, type of cultivation, types of chemicals for agricultural use utilized, equipment used to apply the product, contact with pesticides, knowledge of the risks of pesticides to human health, guidance on the risks at work, type of information about these risks, training on first aid, packaging disposal and use of personal protective equipment , who conducted the training, use of PPE to handle the products, which PPE were used, if after the use of pesticides any specific hygiene routine was implemented and what they were. To understand the possible effects of the chronic use of pesticides on the health of rural workers, a questionnaire that consisted of questions concerning: incidence of poisoning by pesticides, tinnitus, dizziness presented during or after contact with pesticides and the presence of otorrhea and earache was used. The otoscopy was performed in all rural workers to check the integrity of the pinna and ears as to the existence of injury such as obstruction of the external auditory meatus, perforated eardrum and hearing of non-occupational origin. Those who submit any such changes would be excluded from research. Data was analyzed employing descriptive and inferential statistics. Statistical analysis was performed using SPSS software, version 11.0. Quantitative variables were described by mean and standard deviation. The results were presented in tables. To determine the association between the qualitative variables in the study, we used the chi-square test. The significance level was 5%, where significant values of p ≤ 0.05 were considered. All received information related to the research and later signed the Consent and Informed Agreement  according to Resolution No. 196 of October 10, 1996 of the National Health Council , involving research on human subjects. The project was submitted to the Ethics Committee of Caratinga University Center where he received permission for the study was conducted.

In order to trace the socioeconomic profile and lifestyle sample in the study, the parameters whose results are in Table 1, hydroponic nft channel were considered. Define According to the data reported in Table 2, the study population was composed of individuals with a mean age of 36.7 ± 9.3 years, only for males. Regarding education, 69.6% attended elementary school from 1st to 5th grade; 21.7% reported having attended 6th to 9th grade and 8.7% attended high school. When asked about the monthly income, 60.9% said they receive a minimum wage per month; 21.7% receive less than the minimum wage; 17.4% receive between two and three monthly salaries. Considering aspects relative to the use and management of pesticides and in view of the working time in coffee and tomato plantations, 8.7% reported that they worked less than three years; 13.0% from 3.1 to 5 years; 8.7% 5.1 to 10 years; 26.1% from 10.1 to 15 years; 43.5% more than fifteen years . When asked about smoking habits, 30.4% said they smoke; 69.6% reported that they did not. In regards to consumption of alcohol, 52.8% said they consume alcohol; 47.8% do not consume alcohol. Regarding the daily working period, 8.7% work six hours a day; 56.5% eight hours; 17.4% ten o’clock; 8.7% twelve hours and other remaining 8.7% could not inform about the time spent at work . An important factor for the increased risk of exposure to pesticides refers to the use and handling of these products, Table 2 reported the findings relating to the variables that characterize this practice. As recorded in Table 2 and considering the type of existing agriculture in rural Piedade de Caratinga, it was found that 43.5% of the crops are tomatoes; 30.4% coffee; 13% culture both  and 47.8% other types of crops ranging from vegetables and fruits. Technical analysis about the type of agricultural defense used in coffee, tomato and other crop cultivation, there are a series of pesticides used, listed as follows: Roundup®  whose toxicological classification is III, Manzate®  toxicological class I, Vertimec®  belonging to class III, Meothrin®  followed by Tamaron®  with extremely toxic type I toxicology . For the application of these pesticides it is necessary to use their own equipment, these workers were asked about what equipment they used. The results of the answers are shown in Table 2, where it is possible to verify that 13% use the bar and hose sprayer for application in the crops; 69.6% manual knapsack sprayer; 13% use the mechanized knapsack sprayer; 26.1% use the stationary spray with motor and another 4.3% use of another form of application. Regarding the handling of pesticides, the question was asked about how contact with the product would be. 78.3% said that the only contact had with the pesticide would be when it is applied; 73.9% in the preparation of the solution; 52.2% during the cleaning of the equipment and utensils; 52.2% during transportation and storage; and 30.4% said that contact with pesticide is had when entering a crop soon after application . According to Table 2 in regards to the use of some kind of personal protective equipment  39.1% said they use; 39.1% said they did not use and 21.7% reported that they sometimes use it. When asked if they received any guidance on the risks that this type of work with pesticides could cause, 65.2% answered that yes, they received information about the risk inherent to this type of work and 34.8% reported that they received no guidance about the real risks of handling pesticides.Still about this same matter, workers were asked who passed these guidelines to them, 80% said that friends, family and other people guided them and 20% that neighbors were responsible for keeping them informed. Regarding first-aid training, disposal of pesticide containers and PPE, 21.7% said they received training and 78.3% did not . Regarding the use of PPE for the application of the product in crops, 43.5% said that they use protection adequately, 34.8% do not use PPE and 21.7% that they sometimes use it. Still related to this topic, they were asked about which PPE they used to avoid direct contact with pesticides, 69.6% said they use boots for prevention; 43.5% gloves; 39.1% hats; 26.1% impermeable clothing; 56.5% chemical masks and 8.7% reported using other forms of protection .

Considering the data in Table 2, in relation to the hygiene procedures soon after application of pesticides, 82.6% said that they performed a hygiene routine and 17.4% did not. When asked about what specific hygiene habits they adopted; 87% answered that they wash their hands and face every time they deal with a pesticide; 91.3% who take a complete bath after working with pesticides; 69.6% change clothes right after using these products and 65.2% said they avoid eating or smoking during the application of these products. The routine use of these harmful pesticides is harmful to health, it was asked if some of these workers showed some type of intoxication, 30.4% said they already showed signs of intoxication and 69.6% have never had such signs. The last question of this questionnaire, was about if soon after the application of pesticides, there was some sign or symptom relative to the use of these products; 21.7% said they felt dizzy; 26.1% had difficulty hearing; 21.7% lack balance; 30.4% nausea; 34.8% felt congestion in ear; 13% vomiting; 34.8% ringing in the ears; 8.7% tearing and ear pain; 21.7% no symptoms and 43.5% presented other types of signs and symptoms.