Levels and ecological risk assessment of UV filters in sediments of Odo-Iyaalaro River and Eleyele Lake, Nigeria

The presence of UV filters in freshwater sediments could present detrimental health effects to the aquatic organisms. This study aimed to investigate the contamination level and ecological risk of five commonly used UV filters (benzophenone-3 (BP-3), 2-ethylhexyl-4-methoxylcinnamate (EHMC), 2-ethylhexyl salicylate (EHS), 4-methylbenzylidene camphor (4-MBC) and octocrylene (OCR)) in sediments of Odo-Iyaalaro River and Eleyele Lake in Nigeria. Extraction was carried out by ultrasonication with methanol while instrumental analysis was achieved by high performance liquid chromatography with ultraviolet detection. Risk quotient (RQ) approach was adopted for assessing the potential ecological risk of target UV filters. Overall recoveries at low fortification level 25 ng g−1 ranged from 77% (BP-3) to 119% (4-MBC). Repeatability ranged between 5 and 19% while reproducibility ranged from 8 to 27%. LODs ranged from 0.5 ng g−1 (for 4-MBC) to 6.8 ng g−1 (for EHS). The highest mean concentration of 26.4 ng g−1 was quantified for OCR in Odo-Iyaalaro sediments. RQ values were generally less than 1 except for EHMC which had RQ values of 8.63 and 9.75 in Odo-Iyaalaro River and Eleyele Lake, respectively indicating that only EHMC posed a moderate risk to benthic/pelagic organisms while other studied UV filters presented no or low risk. For the first time, the target UV filters were quantified and assessed for potential risks in river and lake sediments in Nigeria. This study underscores the necessity for environmental monitoring of Odo-Iyaalaro River and Eleyele Lake sediments for UV filters (especially EHMC) to safeguard the health of benthic/pelagic organisms.