LAUSR

In early August 2017, a serious palm stearin pollution accident occurred in the Pearl River Estuary, South China. While there were already several palm oil related spills around the world, ecological effects and risks of such accidents to coastal marine environments remain largely unknown. In this study, we found that all seawater and sediment samples collected from six coastal sites were heavily contaminated by palm stearin within one week of the accident, and their levels significantly decreased to pre-accident levels after four months. Waterborne exposure to palm stearin resulted in growth inhibition to four microalgal species (range of EC50: 9.9-212.6 mg/L) and acute mortality to four invertebrate species (range of LC50: 4.6-409.3 mg/L), while adverse chronic effects of palm stearin on the survival, development and fecundity of Tigriopus japonicus, and on the growth of Oryzias melastigma were observed. Based on these results, its interim predicted no effect concentration was determined as 0.141 mg/L. The hazard quotient of palm stearin greatly exceeded one in all sites in August 2017 but returned to be <1 at four sites and <2 at the other two sites in November 2017, indicating that its ecological risk was relatively transient and short-term.