Human health and ecological risk assessment of pesticides from rice production in the Babol Roud River in Northern Iran

Increasing agricultural activities result in increasing use of different pesticides in order to protect the products, but this is happening without paying attention to the consequences of the daily increase of using pesticides. Pesticides could affect human health and the environment at the same time. In this study three pesticides (diazinon, carbaryl and butachlor), which are used in rice production, were measured in the Babol Roud River located in Mazandaran province in Northern Iran. A large portion of the agricultural land use in this region is for rice production. Water samples were collected from 8 sampling points along the river during 4 seasons throughout the year, since planting of rice is conducted twice a year in this region. Mean concentrations for diazinon are 367.7 and 354.5 μgL −1 in October 2018 and June 2019, respectively. Also, concentrations of carbaryl are 197 and 211.1 μgL −1 and butachlor are 299.6 and 413.2 μgL −1 in 2018 and 2019, respectively. Moreover, hazard quotient (HQ) for non-carcinogenic health risk of these pesticides were calculated based on the United States Environmental Protection Agency reference dose (RfD) and the European Union's acceptable daily intake (EU ADI). HQs for adult based on RfD are 4.3, 0.3 and 0.1 and for children are 8.6, 0.08 and 0.03 for diazinon, butachlor and carbaryl, respectively. Also, HQs for adults based on the EU ADI are 15, 0.05 and 0.1 and for children are 30, 0.1 and 0.4 for diazinon, butachlor and carbaryl, respectively. The probabilistic ecological risk assessment indicated that diazinon in the river represents a considerable risk to invertebrate and vertebrate communities, carbaryl to invertebrate communities, and butachlor to primary producer communities. The 5th centile of the species sensitivity distributions for each of these communities of biota are exceeded in more than 75% of samples.