Spatial characterization and health risk evaluation of residual phenol five years after a river pollution incident

The long-term health risk posed by the residual pollution from sudden river pollution incidents receives wide attention but the essential valuable information for health risk management has been reported rarely. In this study, a phenol spill in 2012 that occurred in Yangtze River was investigated to examine the distribution and risks of residual pollution. The average concentrations of phenol were determined to be 2.08 µg/L (range 1.00-8.00 µg/L) in surface water, 5.46 µg/kg (range 2.30-26.60 µg/kg) in sediment, and 2.45 µg/kg (range 0.05-7.00 µg/kg) in soil. The largest increment in phenol pollution was observed in sediment (3.28 µg/kg), while the greatest proportional rise (130.00 %) was recorded in surface water. Areas of high phenol pollution were estimated to cover 12.2 km² in surface water and 16.7 km² in sediment, with a spatial separation of approximately 9.4 km. The non-carcinogenic health risks of oral exposure to phenol were calculated as 9.40 × 10⁻⁴ for infants, 7.23 × 10⁻⁴ for children, 5.15 × 10⁻⁴ for teenagers, and 5.04 × 10⁻⁴ for adults. These findings suggest that phenol followed a deposition-release pattern between sediment and surface water, and a framework were proposed for evidence-based environmental health risk management of residual pollutants in major river pollution incidents.