Estimation of the riverine input of organic ultraviolet filters (OUVFs) from the Pearl River Estuary to the South China Sea during the early Covid-19 pandemic

Organic ultraviolet filters (OUVFs) are functional ingredients used in cosmetics to protect skin from the harmful effects of ultraviolet (UV) radiation. This study presents recent findings on the distribution of OUVFs in the Pearl River Estuary (PRE), located in southern China. This investigation was conducted during the early stages of the Covid-19 pandemic when the stay-at-home policy was implemented. Analysis revealed the presence of OUVFs in both the surface and bottom water samples collected from eight major outlets of the Pearl River. The OUVFs were detected in both the dissolved phase and suspended particulate matter, with a total concentration ranging from 7.19 +/- 6.54 to 20.5 +/- 9.62 ng/L. Notably, OUVFs' concentrations in the study period were significantly lower compared to those reported before the pandemic. This implies that effective reduction of OUVF emissions can be achieved through usage reduction combined with the management of direct discharge and appropriate treatment by urban wastewater treatment facilities. During the study period, the annual release of OUVFs was