By Felipe Muñoz, Postdoctoral Researcher, Instituto de Ciencias de la Salud, Universidad de O’Higgins
Recent research from our team at the Universidad de O’Higgins in Chile suggests concerning evidence that pesticide exposure could potentially affect hearing – even for those who simply live near agricultural areas. While previous studies have focused on farm workers handling pesticides directly, our research indicates that just living close to areas where pesticides are sprayed could cause measurable changes to auditory function, particularly in high-frequency hearing ranges that would be crucial for understanding speech in noisy environments.
Our study, conducted in Chile’s O’Higgins Region (an area with intensive agricultural activity and high pesticide use), compared young adults living within 400 meters of monoculture fields to those living farther away. Using comprehensive hearing tests, we observed that people living near agricultural areas appeared to show potentially higher hearing thresholds at high frequencies (14-16 kHz). To provide context, young adults typically have a hearing range of up to 20 kHz. There also seemed to be more frequent absence of otoacoustic emissions (sounds produced by healthy outer hair cells) and what could be interpreted as reduced amplitude of auditory brainstem responses, possibly suggesting impacts on neural transmission.
These subtle changes occurred in young adults with otherwise normal hearing, which might indicate that environmental pesticide exposure could potentially cause early damage that might not be detected by standard hearing tests. The implications could be significant as these early signs of auditory dysfunction might potentially progress to more severe hearing problems over time, possibly affecting the ability to understand speech in noisy environments – a crucial skill for social interaction and occupational performance.
Our findings support growing evidence that pesticides could damage the auditory system through multiple mechanisms, potentially including possible disruption of cholinergic transmission (important for auditory processing), what might be oxidative stress in cochlear structures, and potential interference with the auditory efferent system that could protect hearing. For communities living near agricultural areas, these findings might highlight the need for enhanced protective measures and regular monitoring of auditory health. We would suggest considering high-frequency hearing tests in health screenings for these populations to potentially detect early signs of damage. Policymakers might want to consider these findings when establishing buffer zones between residential areas and pesticide application, while farmers could explore alternative pest management strategies that might reduce reliance on potentially ototoxic chemicals.
Find a link to the research here.
This research was conducted by the Sensory, Perceptual, and Cognitive Neuroscience Laboratory at the Institute of Health Sciences, University of O’Higgins, Rancagua, Chile. The other authors of the paper are Cristian Aedo-Sanchez, Felipe Paredes-Aravena, Enzo Aguilar-Vidal, Pedro Jilberto-Vergara, and Gonzalo Terreros (Head of lab).
