Health risk assessment and spatio-temporal distribution of polycyclic aromatic hydrocarbons in sediments of Al Hoceima Bay (Mediterranean Coast of Morocco)

In this study, we examined the concentration and distribution of polycyclic aromatic hydrocarbons (PAHs) and organic matter pollution in sediments from Al Hoceima Bay on the Mediterranean coast of Morocco, and we also conducted a health risk assessment. In total, the samples were collected in 2019, 2020, and 2021 from 16 sampling sites and analyzed in the laboratory. The achieved results showed 18 types of PAHs and the average concentrations of PAHs and Organic matter were estimated at 14.2069 μg kg −1 ±30. and 1.73 % ± 0.24, each. The highest concentration of OM was recorded in S14 (3.85 % ± 4.07), mainly in 2020 and 2021 (1.95 % ± 2.47 and 1.88 % ± 0.88, respectively; p > 0.05). The highest concentrations of PAHs were recorded in S15 (22.56 μg kg −1 ±22.43), S13 (18.48 μg kg −1 ±20.85), and S8 (16.33 μg kg −1 ±14.85), mainly in 2019 (4.75 μg kg −1 ±1.39). The concentration of PAHs was significantly superior in September (16.09 μg kg −1 ±12.31) compared to March (10.62 μg kg −1 ±10.46). PAH, Naph, and Naph-2-m were the most dominant with concentrations of 99.09 μg kg −1 ±91.99 and 92.59 μg kg −1 ±91.08, respectively. Correspondence Analysis (CA) showed that in March and September of 2019, six sites (S1, S2, S10, S11, S14, and S16) showed a higher concentration of PAHs, in September 2020 two sites (S3 and S9) showed a higher concentration of PAHs, while in March 2021, (S4, S5, S6, S7 and 15) showed the highest concentration of PAHs. Sites S1 and S14 were characterized by Fle, Acy, Chy, BaA, Flu, Pyr, BbF, Bghip, DBahA, and IcdP, S2, S11, and S12 were associated with Phe, BaP, Ant, and BkF, and S3, S4, S7, S8, S9, S13, S15, and S16, were dominated by Naph, Naph-1-m, and Naph-2-m. In contrast, S5, S6, and S10 were dominated by Ace. These findings are suggested to offer a reference for future investigations. The gathered data in this study should be used as a baseline reference concentration and for risk assessment by policy and decision-makers to monitor biodiversity, sediment–water quality, and economic activities along the Moroccan Mediterranean coastal zones. The Incremental Lifetime Cancer Risk (ILCR) values indicate a significant concern for human health, especially in September, with dermal contact being the primary exposure route. Furthermore, continued long-term monitoring is necessary to minimize human exposure to PAHs throughout the year.