15
Oct
Study Finds Disproportionate Risk of Respiratory Effects in Latino School-Aged Children in California
(Beyond Pesticides, October 15, 2024) In Environmental Epidemiology, researchers from Columbia University and the University of Southern California, along with representatives from the nonprofit Comite Civico del Valle in Brawley, California, report the heightened risk of wheezing for five- to twelve-year-olds in the rural communities of California’s Imperial Valley. Through a school-based survey, the authors find associations between living near pesticide applications and more wheeze symptoms among the children.
According to the authors, residents of the Imperial Valley, which is located near the border between the United States (U.S.) and Mexico, “are primarily Latino, 1 in 3 children live in poverty, and there is a 20% unemployment rate. The county faces poor air quality and excess particulate matter levels. Further, one in five children is diagnosed with asthma and the rate of asthma-related pediatric emergency room visits and hospitalizations is two times the CA state average.†This highlights the disproportionate risk for residents in this area regarding environmental exposure to harmful chemicals.
Children are already more susceptible to health complications following pesticide exposure, as they take in greater amounts of toxic chemicals relative to their body weight and have still-developing organ systems. Young children in environments with higher levels of pesticide usage and pesticide drift face an even greater threat, such as in the Imperial Valley. The authors note, “Industrial agriculture in the region results in one of the highest amounts of pesticide applications in the state, with Imperial County ranking in the top 12 (of 58 counties) since 2017.â€
The purpose of this study, the authors share, is to “assess the respiratory health impacts of pesticide usage in a rural, structurally marginalized population of school-aged children.†This is of particular importance, as the respiratory health of children can lead to long-term consequences into adulthood. The Assessing Imperial Valley Respiratory Health and the Environment (AIRE) study was initiated as a result of the concern among residents and community organizations about cumulative effects and body burden from the copious amounts of pesticides used in the Imperial Valley.
“In this intensively farmed community, fields are planted and harvested several times a year. There are over 100 different types of crops cultivated and over 50 pesticides (differentiated by active ingredient) used in Imperial Valley amounting to over five million pounds of pesticides applied annually,†the authors state. “As schools and homes are located in close proximity to agricultural fields, exposure to pesticides is of great concern.†To address this, the AIRE study provides an analysis of pesticide usage from 2016-2020 within 400 meters (m) of the homes of over 700 children.
Elementary school-aged children from five schools across five communities throughout the Imperial Valley were considered in the voluntary study. With a parent or guardian’s consent, eligible students received questionnaires. These consisted of demographic and lifestyle questions, as well as an inquiry of respiratory symptoms based on questions adapted from the International Study of Asthma and Allergies in Childhood (ISAAC). After which, 708 children participated in the questionnaire and were enrolled in the AIRE study.
In describing their methodology, the authors say, “For each child, we computed the total pesticides applied within a 400-m buffer distance of their home, using a reported address from the questionnaire, for the 12 months before the date of the baseline survey using the following pesticide groups: all pesticides, all pesticides except sulfur, sulfur only, chlorpyrifos only, and glyphosate only.â€
In choosing the 400 m buffer parameter, the authors consider that there are “(1) previous studies identifying an association between a 500-m buffer correlation with pesticides measured in homes located near agricultural fields and (2) a 2018 law in California that limits the application of pesticides within 402 m (1/4 mile) of schools.†This provides 400 m as “a buffer with both scientific and policy implications,†the authors note. While this law recognizes concerns in California about children’s exposure to pesticides, it is limited to contiguous areas around schools and does not consider the amount of residential exposure, especially in rural areas, that many children face.
With information from the questionnaires, along with data from the California Pesticide Use Registry in the areas surrounding the children’s homes, the authors are able to assess links between reported respiratory symptoms and pesticide exposure. The exposure levels for each child are categorized into one of three groupings: none, low, and high.
Important statistics the authors share from the study results include:Â
- “Approximately 62% of the 708 children (aged 5–12 years) lived within 400 m of at least one pesticide application within 12 months prior to survey administration.â€
- “There were 130 children (18%) with wheezing in the 12 months prior to the survey.â€
- “Within 400 m of child residences, there were 150 different pesticides applied over a 12-month period. This amounted to a total of 56,824 kg of pesticides applied to agricultural fields in our Imperial Valley study area.â€
- “Applications of sulfur only were the main contributor with a total of 28,060 kg, followed by all pesticides except sulfur (28,763 kg), glyphosate (3319 kg), and chlorpyrifos (523 kg).â€
Of the 708 participants that were enrolled in the study, 658 are included in minimally adjusted models. These participants submitted questionnaires with complete information and a geocoded address that allows for a full assessment. The authors report, “In minimally adjusted models, children in the ‘high’ total pesticide exposure group had a prevalence of 12-month prior wheeze that was 10 percentage points higher than that of children not exposed to any pesticides. Similarly, the difference in the prevalence of 12-month prior wheeze in the ‘high’ exposure group to sulfur compared to the ‘no’ exposure group was 12 percentage points higher.â€
Additional results show higher prevalence in the “high†exposure groups, such as for chlorpyrifos (15%) and glyphosate (9%) when compared to the unexposed groups. An association is also noted for pesticide exposure and respiratory symptoms in children with a history of asthma. Wheezing in these children is, on average, 18.6% greater within the “high†exposure groups for all categories. In children without asthma, the “high†exposure groups are 6% and 10% higher than that among unexposed children in the categories of all pesticides, except sulfur and chlorpyrifos, respectively.
To summarize the results, the authors say, “We observed consistent cross-sectional associations between exposure to pesticides applied within 400 m of children’s residences within the past 12 months and reported wheeze during this time. Those in the highest exposure group experienced a higher prevalence of wheeze compared to unexposed children for all pesticides groups we examined: all pesticides, sulfur only, all pesticides except sulfur, chlorpyrifos, and glyphosate, respectively.â€
They continue, “Associations between exposure to pesticides and respiratory symptoms appear to be higher in children with asthma, but positive, albeit weaker trends, also were observed among nonasthmatic children.†This study shows how detrimental the pesticide drift exposure pathway can be, particularly for rural communities, as living in areas with pesticide applications increases the risk of health effects. The results indicate that individuals with already documented health effects are more susceptible to additional respiratory implications, but all exposed children are still in jeopardy.
The authors also highlight the role of environmental justice, saying, “Disparities in pesticide exposures by race/ethnicity also persist, with higher exposures concentrated in structurally marginalized communities.†The AIRE cohort consists primarily of children from under-resourced Latino families, the authors note. “[P]esticide use is disproportionately located in communities experiencing the highest levels of poverty, and communities of color. Rural communities such as Imperial Valley continue to rank among the top communities most burdened by toxic pollution, including pesticides.†See additional coverage on environmental justice here, here, and here.
Concerns from residents of the Imperial County, which led to the initiation of the AIRE study, are due to many of the pesticides sprayed in the area being classified as respiratory irritants (e.g., chlorpyrifos, glyphosate, and sulfur). While each of these pesticides has a different mode of action, they are all considered irritants when inhaled. Previous studies link these pesticides to an increase in respiratory symptoms in both children and adults. One study finds that sulfur, used as a fumigant, is associated with an increase in respiratory symptoms and a decrease in pulmonary function in children, while another finds the weed killer glyphosate is associated with atopic asthma. Chlorpyrifos, in addition to pendimethalin and trifluralin, is associated with wheezing in farmers.
The authors note a limited but growing number of studies focused on the association between various types of pesticides and wheezing in children. Such studies (here and here) report increased wheezing in young children with pesticide exposure, particularly pyrethroids. Another California-based study finds decreased lung function with a 10-fold increase in exposure to sulfur within 1000 m of a child’s residence. See more coverage on respiratory implications here and here.
While the escalated health risks to farmworkers and their children have been documented, the AIRE study highlights how “pesticide drift and inhalation may be of greater concern than the take-home exposure pathway†that farmworker families face since the majority of children in the AIRE cohort are not from a household with a farmworker parent or guardian. This calls to attention the proximity of residences to agriculture and how prevalent pesticide drift is, especially in posing a threat to children’s health, as compared to the risk for farmworker children with pesticide residues brought into the house on a parent’s clothing.
The authors conclude, “Pesticide exposures have long been identified by researchers and community voices as an important environmental justice issue impacting not only agricultural workers but also nearby residents. In the United States alone, the agricultural sector accounts for nearly 90% of the total pesticide usage, making agricultural farmworkers, their families, and nearby residents particularly vulnerable to the effects of pesticides.â€
To protect children’s health and mitigate respiratory effects, pesticide applications near residential homes should be eliminated. Chemical-intensive agriculture, as well as the use of household pesticides on lawns and gardens, threatens not only the health and development of growing children but all humans, pets, wildlife, and ecosystems. The Safer Choice to protect human health, biodiversity, and the environment is in organic land management.
Take action to protect the health of infants and children, as well as advocate for the removal of harmful pesticides such as paraquat, to help further Beyond Pesticides’ mission of phasing out all petrochemical pesticides and synthetic fertilizers by 2032. The path forward for a livable future is organic, which focuses on healthy soil as the foundation for land management. Organic methods promote soil health, biodiversity of microorganisms, and ecological functions as a whole. (See more here, here, and here.)
Stayed informed with Beyond Pesticides’ Daily News, which shares the latest news on the health and environmental hazards of pesticides, pesticide regulation and policy, pesticide alternatives, and cutting-edge science. Become a Parks Advocate to encourage your community to transition to organic and join Beyond Pesticides as a member today to support the movement of eliminating fossil fuel-based pesticide use and adopting the organic solution.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source:
Ornelas Van Horne, Y. et al. (2024) Exposure to agricultural pesticides and wheezing among 5–12-year-old children in the Imperial Valley, CA, USA, Environmental Epidemiology. Available at: https://journals.lww.com/environepidem/fulltext/2024/10000/exposure_to_agricultural_pesticides_and_wheezing.2.aspx.
