Chemical composition of marine sediments in the Pacific Ocean from Sinaloa to Jalisco, Mexico

Marine sediments from Mexico's West coast in the Pacific Ocean from Sinaloa to Jalisco were analyzed by energy-dispersive X-ray fluorescence technique. Ten sediment samples were collected in May, 2010 between 55.5 and 1264 m water depth with a Reinneck type box nucleate sampler. Sediments were dried and fractioned by granulometry. Their physical and chemical properties were determined in laboratory by standard methods, pH, and conductivity. Concentration and distribution of K, Ca, Ti Mn, Fe, Cu, Zn, Ga, Pb, Br and Sr were analyzed. In order to determine the status of the elements, enrichment factors were calculated. Total, organic carbon and CaCO3 were also determined. Scanning electron microscopy and X-ray diffraction show predominant groups of compounds. As quality-control method, Certified Reference Material was both processed and analyzed at even conditions. Enrichment factors for K, Ca, Ti, Mn Fe, Cu, Zn, Ga, Ni, and Sr show they are conservative elements having concentrations in the range of unpolluted sites giving a base data line for the sampling zone In spite of moderately enrichment factors <100 μm size and bulk fractions, first Pb concentration fraction was similar to those found in not influenced by anthropogenic activities sites nearby Mazatlan Harbor. Bulk fraction concentration (52-133 μg g-1) and enrichment factor show the influence of anthropogenic sources with values between lowest effect level and a third part of 250 μg g-1value, which is considered to have severe effect levels for aquatic life. (author)