Biomarkers profile and neurobehavioral functioning in pesticide exposed populations in northern Chile.

Abstract

Background. In Chile, several organophosphates (OP) pesticides banned in other countries are still used for insect control in agriculture. Acute intoxications of agricultural workers frequently occur and they must be notified to the surveillance system of the Ministry of Health. However the impact of chronic and environmental pesticide exposure in the general population has been less studied. Long-term exposure to OP is associated to neurobehavioral impairment and is also considered a risk factor for neurodegenerative pathologies.Methods: We recruited volunteers from rural towns located in northern Chile were agricultural activities are carried on. Volunteers (men and women among 18 and 50 years old, with at least 5 years living in the area or working in agriculture) were classified as environmentally (EE) or occupationally exposed (OE) according to a survey that asked sociodemographic, morbidity and exposure antecedents. Each participant underwent a neuropsychological evaluation using a battery of 21 test that covered areas of memory, attention, executive functions, praxis, psychomotricity and emotion. Inhibition values of blood acetylcholinesterase (AChE) and butyrilcholinesterase (BChE) activities during the spray season were obtained in both exposure groups.Results and Discussion: BChE activity was significantly inhibited in EE and OE, showing the EE group the highest magnitude of inhibition. Frequencies of inhibition above 30% (biological tolerance limit declared by Chilean legislation) indicated that AChE is the most frequently inhibited enzyme in the OE whereas BChE is for EE. In pre-spray neurobehavioral evaluations, the OE group showed the highest frequency of low-performance individuals, followed by the EE group. For the majority of tests, the performance worsened during the spraying season. The most affected domains were memory, executive function, and psychomotricity. Poor associations were found between enzyme activities and neurobehavioral outcomes. Systematic biomonitoring and health outcomes studies are necessary to improve environmental and occupational health policies in Chile.