Widespread bioaccumulation of contaminants of emerging concern in Red Sea coral reefs: Evidence from Pocillopora favosa

Coral reefs are increasingly threatened by multiple stressors, including contamination from pharmaceuticals and personal care products, collectively known as contaminants of emerging concern (CECs). This study investigated the occurrence, distribution, and bioaccumulation factors of 10 CECs in the coral Pocillopora favosa across 15 reefs in three central Red Sea regions (Thuwal, Jeddah, Al Lith) spanning a gradient of human pressure. Using SPE and HPLC-MS, CECs from different classes (antibiotics, anti-inflammatories, bronchodilator, central nervous system agents, stimulant, and herbicide) were quantified in coral tissues and seawater. Most CECs were detected in both matrices, with salbutamol and atrazine showing the highest detection frequencies. Bioaccumulation factors indicated uptake of most compounds except caffeine, tramadol, and ranitidine throughout the regions. Unexpectedly, some CECs exhibited higher concentrations offshore than neashore, suggesting complex transport and bioaccumulation dynamics. Results reveal widespread presence of CECs in Red Sea corals and the need for pollution mitigation strategies. • CEC found in corals and water spans from pharmaceuticals, stimulants and herbicides. • SBT was the prevalent CEC in corals, whereas CAF predominated in seawater. • CEC concentrations did not consistently decrease with distance from shore. • All CECs, except RTD and CAF, were bioaccumulative in coral tissues. • Distribution patterns of CECs were region-specific.