Environmental Risk Assessment of Triphenyl Phosphate in Freshwater, Sediment, and Soil

Abstract

Background: Triphenyl phosphate (TPP) is an organophosphate flame retardant known to accumulate in the environment, including in surface water, sediment, and soil, ultimately resulting in toxicity.While continuous monitoring studies on TPP have been reported, ecological risk assessment remains insufficient.Objectives: This study aimed to assess the environmental risks of TPP in freshwater, sediment, and soil in South Korea by applying domestic production, use, and emission data to determine whether environmental concentrations remain below predicted no effect concentrations (PNEC). Methods:The predicted environmental concentrations (PECs) at 30 sites were derived using the SimpleBox Korea model.The measured environmental concentrations (MECs) were investigated by reviewing TPP monitoring information in the South Korean environment.The freshwater PNEC was derived using the species sensitivity distribution (SSD) approach based on chronic no observed effect concentration (NOEC) values for nine freshwater species representing three trophic levels, whereas the sediment PNEC and soil PNEC were calculated by the equilibrium partitioning method.The hazard quotient (HQ) was calculated by dividing the PEC or MEC by the PNEC.Results: The PNEC of TPP was determined as follows: 9.34×10 -5 mg/L for aquatic environments, 2.38×10 -2 mg/kg dry weight (dw) for sediments, and 4.69×10 -3 mg/kg dw for soil.The maximum surface water concentration observed in the monitoring data yielded an HQ of 2.36×10 -1 , indicating no potential ecological risk.When evaluating PECs, HQ exceeded 1 at some grassland sites.In surface water and sediment, all HQ were below 1.Conclusions: The comparison of MECs and PECs with PNECs indicated HQs<1 for surface water and sediment, but HQs>1 for several grassland PECs, suggesting potential ecological concerns.However, actual soil risk is expected to be lower because air emission control efficiencies were not fully considered, resulting in conservative soil PECs.