Pesticide Exposure: Developing Monitoring, Methods and Modeling in Human Health Risk Assessments (Consumer and Worker Risk)

摘要

Introduction: Chile has experienced increase of agricultural activity in recent years, leading to enhanced use of pesticides. Organophosphates pesticides (OPP) cause 39% of occupational acute pesticide intoxications. While acute poisonings are easily diagnosed, chronic exposure often goes unnoticed. Biomarkers available today only serve to diagnose acute poisoning. There is no biomarker available to monitor chronic exposure. Aim: We studied the activity of the erythrocyte enzyme acyl peptide hydrolase (ACPH) as a potential new biomarker for chronic exposure to OPP, relating its activity to cognitive performance and comparing ACPH performance with established biomarkers. Methods: A total of 268 study participants were recruited: 81 environmentally exposed (EE), 87 occupationally exposed (OE), and 100 in a reference group (RG). The population was homogeneous in age, smoking habits, alcohol and drugs consumption. Blood was collected and analyzed for erythrocyte acetylcholinesterase (AChE), plasma cholinesterase (BChE) and erythrocyte ACPH exopeptidase activity. The neuropsychological assessment included general mental state, memory, language, attention, praxis, executive function, psychomotricity and mood. Results: During fumigation, the biological tolerance value (BTV) based on 70 % of individual baseline enzyme activity was exceeded for AChE in 28.2% of EE and 24.4% of OE and in 29.5 % and 16.7% for BChE, respectively and 33.3% and 11.5% for ACPH, respectively (for RG these measurements were not performed). For cognitive performance a fair performance in RG (2% low scores) was observed, whereas both EE and OE showed a significantly lower performance in nearly all tests. The most affected endpoints were memory, executive function and psychomotricity. A predictive model was constructed to relate enzyme activities to cognitive outcomes. In this model the most influential variable was an exposure index based on the number of years of employment and information on OPP exposure from a questionnaire; whereas the biomarkers did not contribute significantly to predict cognitive outcome. Conclusions: Both residents and workers in an agricultural Chilean setting showed cognitive impairment. Biomarker levels indicated higher frequencies of impaired enzyme activities in residents than in workers but did not predict neuropsychological outcome. An index of exposure based on information provided by questionnaire (years living in agricultural area or working in contact with pesticides) was more informative in this respect.