Textural and geochemical characteristics of marine sediments in the SW Gulf of Mexico: implications for source and seasonal change Leticia Rosales-Hoz & Arturo Carranza-Edwards & Raymundo G. Martinez-Serrano & Miguel Angel Alatorre & John S. Armstrong-Altrin Received: 7 August 2014 /Accepted: 6 March 2015 # Springer International Publishing Switzerland 2015 Abstract Two oceanographic cruises were taken during the winter (SAV I, November and December 2007) and summer (SAV II, July and August 2008) across the mouth of the Papaloapan River in the Gulf of Mexico. Surficial sediment samples were collected from shallow (16–30 m), intermediate (30 to 80 m), and deeper areas (≥300 m). Shallow water sediments are coarser, better-sorted, and primarily composed of sands during the winter, while those found in the summer are finer. At depths greater than 30 m, sediments are primarily fine-grained no matter the season. Major element analysis from shallow areas indi- cates higher SiO 2 concentrations during the windy season with negative correlation against Al 2 O 3 during both sea- sons, following the respective abundances of sand and muds. High organic carbon content was observed in shal- low areas during the summer. Trace metals V, Ni, Cu, Zn, Pb, Li, Cr, Co, and Ba were evaluated. The first six metals showed higher average concentration in the deeper areas, although the highest values at some individual sampling sites for Cr, Co, Cu, and Ba were observed in the coastal area. Factor and cluster analysis were used to explain the sediment distribution pattern and the factors that determine the sediment characteristics within the study area. In shal- low areas, four clusters were observed during the winter and five during the summer. The geochemical characteris- tics of the samples in each cluster suggest association with fluvial sediment input, textural characteristics, heavy min- erals, and Cu and Ba concentration. To evaluate the vari- ations in heavy metal concentration, metal enrichment factors (EFs) were calculated. Enrichment in V, Cr, Co, Zn, Ba, and Pb was detected at certain sites, whereas Cu behaved differently. The distribution of Cu enrichment suggests that it may be of natural origin, associated with the lithology of the volcanic continental area. The minor enrichment observed for other elements may be associated with river discharge. According to sediment quality guide- lines, trace metal concentrations of Cu, Pb, and Zn present occasional risks to aquatic organisms. Keywords Surficial sediments . Trace metals . Sedimentary processes . Seasonal changes . Enrichment factors . Gulf of Mexico Introduction A wide variety of studies on trace metal distribution throughout estuarine and coastal plain sediment, focused on contaminated environments, describe trace metal con- centration and identify the source (Feng et al. 2010; Fernandes et al. 2011). These studies are of importance, while assessing environmental quality and behavior, and help decision-makers to make management choices. Studies of the natural processes that affect the textural and geochemical characteristics of sediments in hetero- geneous coastal settings are scarce. Sediment properties Environ Monit Assess (2015) 187:205 DOI 10.1007/s10661-015-4423-8 L. Rosales-Hoz (*) : A. Carranza-Edwards : M. A. Alatorre : J. S. Armstrong-Altrin Instituto de Ciencias del Mar y Limnologia, Universidad Nacional Autónoma de México, 04510 Mexico, D.F., Mexico e-mail: mtlrhoz@gmail.com R. G. Martinez-Serrano Instituto de Geofísica, Universidad Nacional Autónoma de México, 04510 Mexico, D.F., México