Characterization of PAHs in environmentally relevant concentrations of crude oil WAF and its effects on enzymatic biomarkers on Artemia parthenogenetica

Oil seeps and spillage events can harm the environment in various ways. In the ocean, oil may form droplets or remain in the water column, becoming ingested by exposed species and potentially contaminating humans through seafood consumption. This study aimed to characterize and evaluate the toxicity of the water accommodated fraction (WAF) obtained from a solid soil-oil mass after the Brazilian oil spill of 2019 and its effects on enzymatic biomarkers in Artemia parthenogenetica. Cysts and nauplii were exposed to 100 %, 4 % and 0.16 % WAF for 48 h, with toxicological parameters and enzymatic activities measured. GC–MS analysis of the WAF identified 15 of the 16 EPA priority PAHs in the WAF, with ∑PAHs concentrations of ∼200 μg L⁻¹, including toxicants like naphthalene and benzo[a]pyrene. WAF exposure did not affect hatching rate or mortality in A. parthenogenetica. On the other hand, significant increases in CAT, GPx, and GSTs activities, and cholinesterase impairment were observed in nauplii exposed to 100 % WAF compared to the control group. These results indicate that while no individual changes occurred, subindividual metabolic parameters were altered in animals exposed to 100 % WAF, suggesting activation of antioxidant defenses, increased phase II metabolic activity, and neurotoxicity, potentially impacting the development of juveniles of the tested species, and possibly of other marine species and thereby affecting marine ecosystem balance.