title: Sources and distribution of organic matter along the Ring of Cenotes, Yucatan, Mexico: sterol markers and statistical approaches.
abstract: The Yucatan Peninsula is a large low lying platform of limestone, dolomite and evaporite deposits, forming an extensive and mature karst aquifer with many sinkholes locally called cenotes. In Yucatan, the only source of drinking water is groundwater and its quality could be impaired by: (i) infiltration of contaminants and (ii) saltwater intrusion. To investigate the sources of organic matter in this aquifer, sediment samples (46) were collected from cenotes and analysed using gas chromatography-mass spectrometry. Sterol analysis, coupled with principal component analysis (PCA), allowed us to distinguish three sources of natural organic matter (e.g. marine, autotrophic and terrigenous) and to detect an anthropogenic input (e.g. fecal contamination). Good consistency was observed between the source assignment and the land use context (forest, agricultural, rural or urban areas) and the season, except for some of the samples where a direct correlation could not be made. The latter cases are most likely a result of the karstic character of the system.
authors.affiliation: Unidad de Química-Sisal, Facultad de Química, UNAM, Puerto de abrigo S/N, Sisal, Yucatán 97355, Mexico. Electronic address: mderrien@gmail.com.
authors.forename: Morgane
authors.initials: M
authors.lastname: Derrien
authors.affiliation: Unidad de Química-Sisal, Facultad de Química, UNAM, Puerto de abrigo S/N, Sisal, Yucatán 97355, Mexico.
authors.forename: Flor Arcega
authors.initials: FA
authors.lastname: Cabrera
authors.affiliation: Unidad de Química-Sisal, Facultad de Química, UNAM, Puerto de abrigo S/N, Sisal, Yucatán 97355, Mexico.
authors.forename: Nadia Libertad Velazquez
authors.initials: NL
authors.lastname: Tavera
authors.affiliation: CINVESTAV-IPN Mérida, Km 6 Antigua Carretera a Progreso, Mérida, Yucatán 97310, Mexico.
authors.forename: Cristian A
authors.initials: CA
authors.lastname: Kantún Manzano
authors.affiliation: Unidad de Química-Sisal, Facultad de Química, UNAM, Puerto de abrigo S/N, Sisal, Yucatán 97355, Mexico.
authors.forename: Santiago Capella
authors.initials: SC
authors.lastname: Vizcaino
mesh_terms: D004784:Environmental Monitoring / Q000379:methods*; D005618:Fresh Water / Q000737:chemistry*; D008800:Mexico; D013261:Sterols / Q000032:analysis*; D014873:Water Pollutants / Q000032:analysis*
chemical_list: D013261:Sterols; D014873:Water Pollutants
keywords: Karst aquifer; Organic matter; Principal component analysis; Sinkholes; Sterols