Concentrations of elements and metals in sediments of the southeastern Gulf of Mexico

Abstract.

This paper deals with the extent of contamination in sediments of the southeast Gulf of Mexico. The concentration of elements (SiO₂, Al₂O₃, Fe₂O₃, Na₂O, MgO, CaO, and K₂O) and heavy metals (Cu, Cd, Zn, Co, Pb, Ag, Cr, Ni, V, and Ba) were determined. The elemental composition of sediments is influenced by the Grijalva–Usumacinta–Terminos System at the east and the Tabasco lagoon system (El Carmen–La Machona) at the west coast of the study area. Concentrations of Ni, V, and Ba were anomalously high at some sites. Oil production activities in the vicinity of the sites may be responsible for the high values. Correlations of metal concentrations to elemental composition were performed. No significant relationships between metals and elements were found for most metals (p>0.05), suggesting that metals are not significantly associated with naturally occurring aluminosilicates, iron hydroxide, and calcium carbonate minerals of sediments. Other sources such as organic matter may be contributing to the total concentration of metals. The comparison of metal content in sediments of the southeast Gulf of Mexico with metals of the other areas of the Gulf of Mexico suggests that it is relatively contaminated with Cd, Pb, and Ni. The probable causes of contamination are briefly discussed.