The potential accumulation of polycyclic aromatic hydrocarbons in macroalgae from the Egyptian coast of the Red Sea

In the marine environment, polycyclic aromatic hydrocarbons (PAHs) constitute one of the most pervasive and harmful types of organic pollutants. They pose an additional hazard to marine creatures' resilience due to ongoing climatic change. Therefore, determining their concentration and source is important for estimating their possible risks. Utilizing (GC–MS), we analyzed PAH levels in marine algal tissues along the Red Sea's Ras Gharib coastline. The present study covered the collection of seven Red Sea macroalgae namely; Sargassum cinereum, Caulerpa racemosa, Ulva intestinalis Linnaeus, 1753, Turbinaria ornata, Hormophysa cuneiformis, Ulva lactuca, and Cystoseira myrica) from the Ras Gharib coastline. Sixteen PAHs were found at quantities ranging from 159.67 to 261.57 ng/g in all of the examined marine algal tissues. The average concentration of the 16 PAHs was the highest in S. cinereum and the lowest in U. lactuca. The mean concentration of benzo(a)anthracene (BaA) in S. cinereum was 74.12 parts per billion (ng g⁻¹). Two- and three-ringed PAHs with a lower molecular weight amounted to 2.51 to 23.54% of all PAH components in algal tissues. The average contribution of the eight cancer-causing PAHs to the total TEQcarc of the investigated species was sequentially as follows: BaP (50.23%), BaA (32.18%), BbF (6.52%), BkF (5.20%), IP (4.50%), and Chr (2.00%). The results of the diagnostic ratios demonstrated that the primary causes of most PAHs were combined pyrogenic and petrogenic activities. This suggests employing these indicators to investigate the biological impacts of PAHs pollution and establish its bioavailability in the marine environment.