Assessment of polycyclic aromatic hydrocarbons in three environmental components from a tropical estuary in Northeast Brazil

Highlights: • Low levels of PAH were determined in three compartments from tropical estuary, Brazil. • Diagnostic ratios showed a mixture of sources, with prevalence of pyrogenic source. • PCA presented a PAH distribution in particular groups to water, sediment, and oysters. • The risk quotient showed a range from low to moderate in surface water and sediments. • PAH of 4 rings, mainly pyrene, were found due bioaccumulation in the oyster samples. The evaluation of occurrence, risk quotient (RQ), bioaccumulation factor (BAF), and sources of PAH was conducted in Sergipe-Poxim estuarine system. PAH distribution that ranged from 7.1 to 30.9 ng L⁻¹ (surface water, SW), 5.4 to 19.5 ng g⁻¹ (sediment, S), and 4.3 to 18.1 ng g⁻¹ (oyster, O), characterized the environment with low contamination; 2-3 (SW), 5-6 (S), and 4 (O) PAH rings accounted for 54.5%, 68.7%, and 87.7%, respectively, along with naphthalene (SW), dibenzo(a,h)anthracene (S), and pyrene (O) as the prevailing compounds. PCA suggested the predominance of particular groups related to SW (LMW-PAH), S (HMW-PAH), and O (pyrene and fluoranthene). Furthermore, one sample of O presented a high PAH bioavailability as shown through the BAF, with emphasis on pyrene (BAF = 26.8). The RQ showed a low to moderate range in SW and S; hence, in-depth information about the possible toxic effect in organisms of this region is required.