University of Guilan Caspian Journal of Environmental Sciences 1735-3033 22 3 2024 07 01 Evaluating concentration, distribution, and risk assessment of organophosphate pesticides in paddy fields of Sepidrud River watersheds, Rudbar county, Guilan Province, Iran 621 626 7910 10.22124/cjes.2024.7910 EN Behrooz Azh Baragoori Department of Environmental Sciences and Engineering, Lahijan Branch, Islamic Azad University, Lahijan, Iran Hasan Karimzadegan Department of Environmental Sciences and Engineering, Lahijan Branch, Islamic Azad University, Lahijan, Iran Mohsen Mohammadi Galangash Department of Environmental Sciences and Engineering, Faculty of Natural Resources, University of Guilan, Sowmeh-Sara, Iran Fatemeh Shariati Feizabadi Department of Environmental Sciences and Engineering, Lahijan Branch, Islamic Azad University, Lahijan, Iran Leila Ooshaksaraei Department of Environmental Sciences and Engineering, Lahijan Branch, Islamic Azad University, Lahijan, Iran Journal Article 2024 08 01  <br />Organophosphate pesticides are widely used in agriculture fields as an effective method against pests. However, concerns about the toxicity effects of these compounds on the non-target organism have grown in recent years. The aims of the present study were to assess the concentration, distribution, and biological risk of organophosphate pesticides in the paddy rice of Guilan Province in the Northen Iran. For these purposes, paddy samples were taken from 12 stations and 36 paddy fields in the watershed of Sepidrud River in the precinct of Rudbar County. Samples were analyzed to assess the concentration, distribution, and risk assessment of Diazinon and Malathion as famous commercial formulations of organophosphate pesticides. Results of the present study showed that the average residual Diazinon and Malathion concentrations in samples were 1.226 ± 0.71 and 0.422 ± 0.06 ppb, respectively. In addition, the health risk index (HRI) was 0.08. According to the results, the average concentration of organophosphate pesticides and the health risk for rice consumption was lower than the standard of Plant Protection Organization in Iran and may not be a serious hazard for people who eat rice regularly. However, due to a significant correlation between the consumption of these pesticides by elevating their residual in paddy fields production, it is necessary to monitor and management organophosphate pesticide application in paddy fields. The results of the present study can be considered as a basic information for future environmental studies and health risk management of agricultural produce. https://cjes.guilan.ac.ir/article_7910_58f3ecb9a029f705eee56b33cc51a595.pdf