Source identification of n-alkanes and isoprenoids using diagnostic ratios and carbon isotopic composition on crude oils and surface waters from the Gulf of Mexico.

Autor: Hernández-Guzmán FA; Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico., Macías-Zamora JV; Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico. vmacias@uabc.edu.mx., Ramírez-Álvarez N; Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico., Quezada-Hernández C; Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico., Ortiz-López R; Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico.
Jazyk: angličtina
Zdroj: Environmental monitoring and assessment [Environ Monit Assess] 2021 Sep 07; Vol. 193 (10), pp. 633. Date of Electronic Publication: 2021 Sep 07.
DOI: 10.1007/s10661-021-09440-0
Abstrakt: Diagnostic ratios and compound-specific isotopic analysis (CSIA) are two tools that can help identify and differentiate the petrogenic and biogenic sources of hydrocarbons found in environmental samples. The present study aims to evaluate the concentration and type of n-alkanes and isoprenoids found in the oligotrophic waters of the Gulf of Mexico (n = 14), and through the typical diagnostic ratios reported for n-alkanes and its carbon isotopic composition (δ 13 C) to establish and differentiate the possible source of the hydrocarbons. Additionally, crude oil samples (n = 10) extracted in the Gulf of Mexico were evaluated by CSIA as a possible source of hydrocarbons to the study area. We found that the CSIA of δ 13 C for n-alkanes (n-C 11 to n-C 30 ) and isoprenoids (pristane and phytane) found in the surface water samples varied from - 25.55 to - 37.59‰ and from - 23.78 to - 33.97‰ in the crude oil samples, values which are more related to petrogenic sources. An analysis of the δ 13 C for pristane vs. phytane suggests that only three surface water samples show an origin in common that those observed in crude oils of the Gulf of Mexico. A low incidence of odd- and even-numbered n-alkanes higher than n-C 25 in the water samples indicate low to negligible presence of terrigenous sources into the area, which was supported by the carbon isotopic composition of the individual n-alkanes.
(© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)
Databáze: MEDLINE
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