Health Risk Assessment of Paraquat Contaminated in Spirogyra spp. (tao) in Chiang Mai, Thailand

Spirogyra spp. (tao) is freshwater green algae which are consumed as an uncooked food especially in the north of Thailand. Aquatic plants especially algae are easily contaminated by pesticide residues from soil and water. Paraquat (1,1β-dimethyl, 4,4β-bipyridinium dichloride; PQ), a widely used herbicide among Thai farmers, is toxic, mutagenic, and carcinogenic to mammals through ingestion, inhalation and skin contact. This study aims to determine the concentrations of paraquat contaminated in Spirogyra spp. (tao) and health risk assessment on the consumption of Spirogyra spp. (tao) in Chiang Mai province, Thailand. The levels of paraquat were analyzed by using a simple, sensitive, and reliable method which was high performance liquid chromatography (HPLC). Seven samples were collected from the different districts. The levels of paraquat contamination were 5.07±0.00 to 12.69±0.10 mg/kg. The results showed that the concentrations of paraquat in all samples were lower than the standard level of the European Commission Regulation. Risk assessment of paraquat found that the hazard quotient was in the range of 0.18-0.46. It indicated that the consumption of Spirogyra spp. (tao) was expected to have no adverse health effects. However, the consumption of Spirogyra spp. (tao) should be a concern in terms of chronic exposure to toxic herbicide contaminated in the environment.