Trace anthropogenic arsenic in Taiwan—substance flow analysis as a tool for environmental risk management

Site-specific risk assessment is intended for single source analysis, and provides limited options to reduce environmental risk. The links between multiple sources and population exposure deserve better understanding. In this way, the industrial activities can be managed to protect the population from the exposure to the substances in multiple environmental media, food, and drinking water. We took the anthropogenic arsenic in Taiwan into our case study. Substance flow analysis was used to map the circulation of arsenic in Taiwan. Emissions from arsenic related industries were modeled to estimate the health risk for each region. From the life cycle perspective, we found the major inputs were the imported ores and fossil fuels. The outputs would be a great concern to future arsenic exposure, because the use of arsenic-containing products is accumulating arsenic in wastes. Under current steady-state emission, the cancer risk in each region ranged from 10−6 to 10−3. The regions of high risk co-exist with fired-power plants, oil refineries, or waste treatment facilities. Several risk reduction strategies were compared. More than 95% of risk could be reduced if all airborne emissions were eliminated. The proposed methodology that integrates substance flow analysis with exposure assessment and risk evaluation offers quick examination on more comprehensive risk reduction alternatives. Further dedicated risk assessment might be required to estimate the more precise risks for the areas or industries that were pre-identified as hot spots.