Iranian population exposures to heavy metals, PAHs, and pesticides and their intake routes: a study protocol of a national population health survey

Cancer is the second leading cause of death in the world and the third leading cause of death in Iran. It has been proven that numerous cancer cases are caused by exposure to environmental pollutants. There is a public health concern regarding an increase in exposure to carcinogens across Iran through different sources (air, food, and water) and a lack of research to address this issue. This study aims to gather data on exposure to heavy metals, polycyclic aromatic hydrocarbons (PAHs), and pesticides and their intake routes during the implementation of a national population health survey. This is a cross-sectional study of environmental pollutants in Iran, with a stratified multi-stage random sampling method, which led to 660 nationally representative samples in 132 clusters in three sequential parts. The first will be questionnaires to obtain demographics, assets, food records, air quality, and food frequency. The second will be physical measurements, including anthropometric and body composition. The third will be lab assessments that measure 26 types of environmental pollutants (7 heavy metals, 16 PAHs, and 3 pesticides) in urine, inhaled air, and consumed food and water of the population under study using ICP-MS and GS-MS devices. The results of this study will inform policymakers and the general population regarding the level of threat and will provide evidence for the development of interventional and observatory plans on the reduction of exposures to these pollutants. It could also be used to develop local standards to control contaminants through the three exposure routes. This study protocol will obtain data needed for policymakers to set surveillance systems for these pollutants at the national and provincial level to address the public concerns regarding the contamination of food, air, and water.