Children's exposure to pesticides used in homes and farms.

Introduction

Pesticides are used extensively inside and outside people's homes, as well as in agricultural fields. Although they offer benefits, keeping insects and rodents out of the house or off farmland, misuse and overexposure to pesticides have been shown to be harmful to humans (Rubin, Esteban, Kieszak, et al., 2002; Rubin, Esteban, Hill, & Pearce, 2002). Children appear to be especially susceptible to the effects of pesticides, and misuse or use at greater-than-recommended levels can lead to exposures that can cause serious acute or chronic illness or even death (Rubin, Esteban, Kieszak, et al.; Rubin, Esteban, Hill, & Pearce).

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The Lower Valley of El Paso County, Texas, consists of residential communities that are located in close proximity to farm fields. Many schools and homes in the area are directly adjacent to or surrounded by fields. Residents in the area have expressed concern about the aerial application of pesticides on these fields, especially during school hours when children are outside. In addition, many residents use pesticides in their homes to kill roaches, ants, mice, mosquitoes, and scorpions. Although many use legal pesticides that can be bought from any grocery or hardware store, some residents are illegally using polvo de avion or methyl parathion in their homes. This pesticide is generally bought in powder form, although sometimes it comes in the form of chalk that can be applied to walls or floors. The pesticide concentration in these forms is varied and unknown. Methyl parathion can be bought from street vendors in the city of Juarez in Chihuahua, Mexico, as well as from some small shops in El Paso, Texas. It is legal only when used on agricultural crops in a restricted manner (Ruckart, Kakolewski, Bove, & Kaye, 2004). When methyl parathion is used outdoors, it degrades in a matter of days (Rubin, Esteban, Hill, & Pearce, 2002). When it is used indoors, however, it degrades much more slowly, with traces of methyl parathion at times manifesting up to a year after initial spraying (Rubin, Esteban, Kieszak, et al., 2002).

Pesticide exposure may be greater in children than adults because of the intensity with which children explore their environment. For example, a child is more likely than adults to be exposed through dermal contact with pesticides as a result of crawling on the floor or through oral contact as a result of placing a contaminated object in his or her mouth (Eskenazi, Bradman, & Castorina, 1999).

Methyl parathion exposure has been shown to cause neurological and physiological damage to humans, and these effects may be more serious in children. Several studies in Mississippi and Ohio have shown that methyl parathion exposure in children may be linked to problems in short-term memory and attention span (Ruckart et al., 2004). Another study suggested that infants living in methyl parathion-contaminated homes may face greater risk of unexplained death (Wasley, Lepine, Jenkins, & Rubin, 2002).

The dangers posed by methyl parathion used inside homes and the concern over aerial crop dusting adjacent to schools and homes make it important to determine peoples' beliefs and attitudes concerning pesticide use in the home and on farm fields. If many people in this region are not aware of the dangers of pesticides, it may be necessary to educate them about the risks. The study reported here looked at what types of pesticides families in the lower valley are using, how frequently they use pesticides, and what methods they use to apply them. If a significant number of families in the lower valley are using organophosphate products, such as methyl parathion, it may also pose a serious public health problem. The authors hypothesized that because of the availability of polvo de avion from Mexican and El Paso vendors and the perceived effectiveness of this pesticide, some people would be using methyl parathion products for application in their homes. In a previous study, the Texas Department of Health (TDH) found about 25 percent of households in this region were using methyl parathion (TDH, 2003). Finally, this study would evaluate what sources people in these communities use to gather health information and how much confidence they place in them. Using the data gathered from peoples' views on where they get health information, we could then work with local community organizations to develop an educational program on proper pesticide use.

Methods

Trained, bilingual interviewers performed door-to-door surveys to assess the use of pesticides in homes and the residents' attitudes and beliefs about pesticide use. One hundred and fifty households were sampled within three major communities in the Lower Valley of El Paso County: Socorro, San Elizario, and Fabens. Twelve to 13 homes were selected randomly from streets within 12 block groups, which were randomly selected from GIS maps (six in Socorro, four in Fabens, and two in San Elizario). Interviewers asked to speak with a person 18 years of age or older who lived in the house and who was the person most involved in pest control in the home. Interviewers explained the purpose of the study and allowed respondents to read and sign the informed consent. All survey questions were read to the participants in either English or Spanish depending on the respondent's preference.

Instrument Development

The instrument included 37 questions, including items based on the Health Belief Model (HBM), items assessing pesticide use and perceptions, and items assessing health information sources and confidence in those sources. Items consisted of statements with Likert-type responses on a scale of 1-4 (with 1 = strongly agree and 4 = strongly disagree). The HBM was developed in the 1950s to explain lack of use of screening and preventive services for the detection and early treatment of asymptomatic diseases (Rosenstock, 1974). The model addresses an individual's "readiness to take action" with respect to a particular health condition and an individual's evaluation of a health action with respect to its feasibility and effectiveness. Readiness to take action is determined both by perceived susceptibility to the health problem and perceived severity of the problem, while an individual evaluates the health action by weighing the perceived benefits of the action against the perceived barriers to action (Maiman & Becker, 1974). The model postulates that individuals will take action to prevent or control illness if they 1) believe that they are susceptible to the illness, 2) believe that the illness would have serious consequences for them, 3) believe that the action would be beneficial in preventing or controlling the illness, and 4) believe that the barriers to taking the action would be outweighed by the benefits (Rosenstock, 1990). This model has been widely applied to various health behaviors.

In addition, some questions were asked about the children living in the household and the type of health care, if any, received by family members. The items about health information sources and confidence were drawn from a survey implemented in a previous study (Byrd, VanDerslice, & Peterson, 1997). Data were entered into the Statistical Package for the Social Sciences (SPSS Data Entry) for management and analysis. The Chi-square statistic was used to determine the statistical significance of cross-tabulations.

Results

The population of the Lower Valley of El Paso is approximately 97 percent Hispanic, with many being monolingual in Spanish (U.S. Census Bureau, n.d.). As a result, 107 of 150 surveys completed were conducted in Spanish by bilingual interviewers (71.3 percent). The majority of the respondents (62.7 percent) were female. Responses to different sets of questions revealed a significant amount of information about pesticide use and perceptions of pesticide safety.

Use of Pesticides

The majority of participants (88.7 percent, or 133 of 150) said they used some kind of pesticide. Most of these individuals used Raid (73.6 percent, or 98 of 133). The pesticide next most commonly used was Combat (22.6 percent, or 30 of 133), which was followed closely by Black Flag (17.3 percent, or 23 of 133). Only 9.8 percent of the people said that they used polvo de avion. The two locations where they said they had purchased methyl parathion were the Dollar Store (four individuals) and Juarez (four individuals). Five people who said that they used polvo de avion stated that they were unsure of where they had purchased it. Two polvo de avion users said that they used it inside the home, one used it both inside and outside, and two used it either on the edge of cabinets or behind the stove. The remaining polvo de avion users used it outside. Several other pesticides were used by the participants but were not listed on the original questionnaire presented to them. The most commonly used of these pesticides was Ortho (6.8 percent, or 9 of 133).

Pesticide Use on Farms

Sixty percent (90 of 150) of the participants reported that they had seen farmers use pesticides in the fields. Of these individuals, 92.2 percent (83 of 90) reported that the farmers never notified them before the pesticides were applied. Of the people who saw farmers using pesticides, 87 percent (78.3 of 90) reported that the pesticides were applied by airplane. Of those who stated that they had seen farmers apply pesticides, 53.3 percent (48 of 90) said that they could also smell the pesticides when they were applied.

Pesticide Safety

Responses to statements related to pesticide safety are given in Table 1. A large percentage of participants agreed or strongly agreed that an illness caused by pesticides would be very serious and that pesticides used in the home could make a child sick (94 percent and 88 percent, respectively). In addition, 83.3 percent of respondents agreed or strongly agreed that pesticide exposure could cause a child to die. The majority (62.7 percent) agreed that pesticides bought for home use were safe if used as directed.

Levels of Information/Confidence in Information

The majority of the participants said that they received almost no information or only a little information about health issues from the following sources: television (52 percent), newspaper (78.7 percent), radio (84.7 percent), private industry/farmers (96.6 percent), city/county health department (66.7 percent), Texas Department of Health (62.6 percent), U.S. Environmental Protection Agency (U.S. EPA) (84.7 percent), university scientists (91.3 percent), and friends/relatives (72 percent). In statements about the level of confidence they had in each channel of communication, the Texas Department of Health was the most trusted source, with 45 percent reporting having quite a bit or a lot of confidence, followed by television and the city/county health department, with 40.6 percent reporting having quite a bit or a lot of confidence. Fewer reported this level of confidence about information received from friends/relatives (28.9 percent), newspapers (22.6 percent), U.S. EPA (21.2 percent), university scientists (17.7 percent), radio (17.1 percent), and private industry and farmers (6.4 percent).

Bivariate Analysis

There were statistically significant differences in responses to attitude questions by respondents who used pesticides and those who did not. As one might expect, those who used pesticides were more likely than those who did not to agree that pesticides are safe (67 percent versus 29 percent respectively, p = .003). In addition, they were more likely to agree that use of pesticides helps to keep the home clean (92 percent versus 71 percent, p = .008), that pesticides make the home a healthier place (93 percent versus 71 percent, p =.005), that they find pesticides useful because they dislike touching bugs (90 percent versus 53 percent, p < .001), and that they are afraid of bugs (74 percent versus 35 percent, p = .001). In addition, those who used pesticides were more likely than those who did not to agree that most people they know use pesticides (90 percent versus 65 percent, p = .003).

By gender, there was only one significant difference in the responses. Men were less likely than women to report that they used pesticides because they were afraid of bugs (55 percent and 77 percent respectively, p = .005). Participants who agreed that pesticides that can be bought for use in the home are safe were less likely than those who thought they are not safe to agree that pesticides used in the home could make a child sick (81 percent versus 98 percent, p = .002). The percentage of participants who agreed that pesticides are safe for home use and also agreed that pesticides used in the home could make a child sick was higher than expected (50.7 percent). Respondents who agreed that pesticides are safe were also more likely than those who did not think they are safe to agree that killing bugs in a home makes the home a healthier place (95 percent versus 82 percent, p = .013).

The responses of people who used polvo de avion did not differ significantly from those who used other pesticides.

Discussion

The factor most relevant to determining the extent of potential exposure to methyl parathion was the fact that 3.33 percent of the residents interviewed admitted to using the pesticide in their homes--a figure far lower than the 25 percent reported by the Texas Department of Health (2003). If this evaluation is accurate, it could indicate that low numbers of people are using methyl parathion in their homes, which may signify an increase in pesticide awareness in the communities sampled, possibly as a result of educational programs that have been disseminated during the last year. On the other hand, it is possible that the educational efforts have simply made people aware that use of methyl parathion is illegal, leading them to respond in a socially acceptable manner, which would mean that the result underestimates the actual use of the pesticide. Also, if this relatively low percentage is generalized to the whole city, which has a population of almost a million, the number is actually quite high, given that methyl parathion is illegal. A thorough examination of the results may, however, indicate that several other variables should be considered. Confirmation of the results would be the goal of future studies.

According to the survey, a high percentage of participants agreed that pesticides that can be bought for use in the home are safe. Over half of respondents who agreed with that statement, however, also believed that pesticides used in the home could make a child sick. This result may suggest that there is at least some level of awareness of the dangers of pesticides in these communities. This idea is supported by the large percentages of participants who agreed that an illness caused by pesticides would be very serious and that pesticide exposure could cause a child to die. The latter percentage also may indicate that the majority of people in these communities are aware that pesticides can be particularly dangerous for children.

A majority of the people surveyed said that they used pesticides. This high number could be a concern; if many people are using pesticides, the likelihood is increased that they may use methyl parathion at some point in the future because of its availability around the area. In addition, it is possible that people are not using the pesticides correctly, thereby increasing the risks and health dangers associated with them. Respondents who used pesticides were more likely than those who did not to believe that pesticides were safe, helped keep their home clean, and made their home a healthier place. The attitudes of people who used polvo de avion were not significantly different from those of people who used any other kind of pesticide. Even though this pesticide is much more dangerous than other pesticides, people who said they used it also said they believed pesticides were safe. This attitude may decrease the precautions people take when using a pesticide that can have effects on human health. For example, five of the respondents mentioned that they use polvo de avion inside their homes. Behavior of this type puts their children at a great risk because they often place contaminated toys or other objects in their mouth, or crawl on the floor where the pesticides have been applied (Eskenazi et al., 1999). Children are exposed to an additional risk if they attend a school that is surrounded by crops to which farmers may be applying potentially dangerous pesticides.

Most people surveyed did not know of ways of ridding their homes of insects other than use of pesticides. Information about alternatives to pesticides in the home may be an important area for health education.

Although the study reported here focused on sampling neighborhoods located in farming areas, future research can examine a wider variety of communities in the El Paso area. Many of the participants mentioned that they had seen the farmers use pesticides, and a majority of them said they could also smell the pesticides. Another concern in these communities is the type of pesticides being used by farmers. Farmers' use of methyl parathion, which is allowed on cotton crops common to the area, can pose a serious health danger to families who live around the fields. Health effects caused by exposure to this pesticide include headaches, nausea, flulike symptoms, vomiting, dizziness, skin rash, and respiratory effects (McCann et al., 2002). In addition, most of these pesticides are applied by airplane, which makes it easier for them to spread through the air to homes in the communities. The report that residents are not notified before aerial application of pesticides is a concern.

As described in the results, a minority of people are actually receiving information from any source regarding health issues. The sources in which people placed the most confidence were the Texas Health Department, television, and the city/county health department. These channels of communication should be utilized in any health education intervention.

The study reported here had several limiting factors, including the fact that results were based on self-reported data, which does not confirm the use of methyl parathion. There may have been a number of people who did not admit to using methyl parathion. In other words, the percentage of participants using methyl parathion might actually be higher than the survey found. Interestingly, people mentioned that they purchased polvo de avion at a Dollar Store in El Paso. If this claim is in fact true, then the product is being sold illegally. It could also be that the pesticide they described as methyl parathion is something else. Further investigation is needed to confirm what pesticides are being bought and used.

Other limiting factors included the fact that all surveys were conducted in the morning, potentially excluding responses from individuals who work during these hours. This factor may explain the disproportionate gender ratio of participants; the higher number of women respondents could indicate that their male spouses, who may be more likely to govern pesticide use in the home, were not available because they were at work. In that case, the number of methyl parathion users may actually be higher than reported. Furthermore, the number of people who refused to participate and the number of people who were not home were not monitored. These limitations make it difficult to access the extent of methyl parathion use because the study may have excluded individuals who are using this pesticide.

To validate the actual percentage of people using methyl parathion or the percentage of people being exposed to it, researchers would need to test homes for its presence via environmental screenings, as with air samples. Once potentially contaminated homes were identified, additional testing could be performed. Biological tests could be conducted, such as measurement of urine samples for the presence of urinary dimethyl phosphate and p-nitrophenol, which have served as indicators of exposure to methyl parathion (Ruckart et al., 2004; Sklansky, Mundt, & Katcher, 2003). The communities have expressed concern over farmers spraying pesticides while their children are playing outside and at school. Therefore, testing could also be expanded to schools to determine the nature of the pesticides being used by farmers in the area. These tests would be imperative not only for increasing public-awareness of the dangers of pesticides, but also for minimizing children's exposure to methyl parathion.

Conclusion

The availability of methyl parathion, or polvo de avion, in the El Paso-Juarez region poses a great risk for residents who are not properly informed about the dangers of this pesticide. The fact that 88.7 percent of the residents interviewed stated they used some kind of pesticides in their homes significantly increases the risk. The fact that only 9.8 percent of people using pesticides admitted to using methyl parathion, however, and a significant correlation between respondents' perceived health risks and beliefs may suggest that residents do have a certain level of awareness about the dangers of pesticides. Future research should aim to specifically evaluate the knowledge of Lower Valley residents about pesticide safety and to confirm what percentage of people are using methyl parathion in their homes; these tasks could be accomplished through environmental and biological screenings. Furthermore, the potential effect of farm pesticides on children could also be evaluated by conducting urine testing at schools adjacent to farm lands.

In addition, the information derived from the study reported here could be used to undertake several preventive measures to enhance public awareness of the dangers of pesticides. Educational programs, videos, and pamphlets should be designed to inform people about the dangers of methyl parathion, and these materials should be distributed through the channels of health information that residents consider most reliable. Since 71.3 percent of the respondents preferred speaking Spanish, the majority of informational tools should be administered in that language. It is also imperative that future studies examine literacy levels in these communities in order to implement the appropriate educational program. After a certain period, a follow-up survey should be conducted to assess residents' knowledge of pesticide risks and determine the effectiveness of the informational tools.

Acknowledgments: The authors appreciate the medical-student support provided by the Pfizer/Association of American Medical Colleges Summer Public Health Program. Also, Dr. Darryl Williams and Joyce Palmer of the Hispanic Center of Excellence at the Texas Tech University Health Sciences Center were instrumental in the completion of this project.

Corresponding Author: Shawn G. Gibbs, Assistant Professor, Environmental and Occupational Health Sciences, University of Texas Health Science Center at Houston, School of Public Health, 1100 North Stanton, Suite 110C, El Paso, TX 79902. E-mail: [e-mail].

REFERENCES

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Eskenazi, B., Bradman, A., & Castorina, R. (1999). Exposure of children to organophosphate pesticides and their potential adverse health effects. Environmental Health Perspectives, 107(3), 409-419.

Maiman, L., & Becker, M.H. (1974). The Health Belief Model: Origins and correlates in psychological theory. Health Education Monographs, 4, 336-353.

McCann, K.G., Moomey, C.M., Runkle, K.D., Hryhorczuk, D.O., Clark, J.M., & Barr, D.B. (2002). Chicago area methyl parathion response. Environmental Health Perspectives, 110(6), 1075-1078.

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Rosenstock, I.M. (1990). The Health Belief Model: Explaining health behavior through expectancies. In K. Glanz, F.M. Lewis, & B. Rimer (Eds.), Health behavior and health education, (pp. 39-63). San Francisco: Josey-Bass Publishers.

Rubin, C., Esteban, E., Kieszak, S., Hill, R.H. Jr., Dunlop, B., Yacovac, R., Trottier, J., Boylan, K,. Tomasewski, T., & Pearce, K. (2002). Assessment of human exposure and human health effects alter indoor application of methyl parathion in Lorain County, Ohio, 1995-1996. Environmental Health Perspectives, 110(S6), 1047-1051.

Rubin, C, Esteban, E., Hill, R.H. Jr., & Pearce, K. (2002). Introduction--The methyl parathion story: A chronicle of misuse and preventable human exposure. Environmental Health Perspective, 110(S6), 1037-1040.

Ruckart, P.Z., Kakolewski, K., Bove, F.J., & Kaye, W.E. (2004). Long-term neurobehavioral health effects of methyl parathion exposure in children in Mississippi and Ohio. Environmental Health Perspectives, 112(1), 46-51.

Sklansky, D.J., Mundt, M.P., & Katcher, M.L. (2003). Pesticides and your children: A randomized controlled evaluation of a pamphlet. Wisconsin Medical Journal, 102(8), 57-62.

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Jeremy Saller

Priscilla Reyes

Pedro A. Maldonado

Shawn G. Gibbs, Ph.D.

Theresa L. Byrd, Dr.P.H.

TABLE 1 Respondents' Perceptions About Pesticide Safety

Statement                                          Percentage Who Agree

Pesticides that can be bought for use in the home  62.7
  are safe.
Pesticides that can be bought for home use can     87.3
  make a child sick.
Pesticides used by farmers on fields can make a    88.0
  child sick.
An illness caused by pesticides would be very      94.0
  serious.
Being exposed to pesticides in the home might      83.3
  cause a child to die.
Pesticides help keep a home clean by killing bugs  89.3
  and other pests.
Killing the bugs in a home makes it a healthier    90.0
  place.
I use pesticides so that I don't have to touch     85.3
  bugs or rodents.
I use pesticides because I am afraid of bugs and   68.7
  rodents.
Most people I know use pesticides in their homes.  87.3
I know of other ways to get rid of bugs, besides   46.0
  pesticides.