Analyzing the quantitative risk and hazard of different waterborne arsenic exposures: case study of Haraz River, Iran

In this study, arsenic concentration of Haraz River water at 20 stations and relative risk and hazard levels regarding ingestion and dermal exposure routes are evaluated. Furthermore, the quantitative threat caused by the consumption of Rainbow trout muscle from the area is also analyzed. The concentration of arsenic increases from upstream areas towards the downstream estuarine zone with a substantial rise in the central part. Arsenic-containing drainage discharged from the Central Alborz coal mine, hot spring spas, as well as municipal (Amol city) and agricultural (numerous rice paddies) land uses that become denser towards downstream are considered as major pollution sources. The inhabitants are not exposed to a significant hazard or risk regarding dermal exposure. However, for the oral ingestion exposure route, all 20 samples present hazard quotient values greater than unity and risk values greater than one in ten thousand. The results show that if the river water is used for drinking, a high-risk status would be imposed on consumers. Finally, the concentration of arsenic in muscle tissues of ten Rainbow trout fish samples was found to range from 0.48 to 1.30 μg/kg of dry weight which is below the allowed daily intake. However, if we consider that lots of other constituents in the total daily intake within the study area contain arsenic, estimated values may be interpreted as a trigger for further health threats.