Evolution of the sources contribution of aliphatic hydrocarbons and their fate in Sepetiba Bay, Rio De Janeiro, Brazil

Sepetiba Bay basin hosts industrial and harbors since the 1950s. Despite this impact history, hydrocarbon levels and sources were evaluated only in the 2000s and 2010s. Therefore, this study aimed to assess the evolution of aliphatic hydrocarbon sources and their fate in Sepetiaba Bay sediments after a significant increase in population, industries, and cargo handling. Surface sediment was predominantly composed of sand and showed a significant difference between TOC (0.20-3.45%) and total n-alkanes concentrations (0.01-3.31 mu g g(-1)) among internal and external sectors of the bay (Mann-Whitney's U test, p < 0.05; n = 26). The n-alkanes concentrations indicate unpolluted sediments and remain in the same order of magnitude of two decades ago. The diagnostic ratios based on major hydrocarbon, isoprenoids, odd/even n-alkanes, and unresolved complex mixture indicate a mixture of allochthonous and autochthonous sources at almost all stations. Even if an oil fingerprint between the internal sector and the harbor area were observed, further studies are required to be sure.