Arsenic Content, Grain Sizes and Chemical Characteristics in Surface Sediments of the Urías Lagoon, Nw Mexico

Abstract

Aiming to detect possible impacts of human activities on the characteristics of the sediments of the Urías lagoon, which is a lagoonal system surrounded by the urban area of Mazatlán (NW Mexico), we determined the mean percentages of the main particle fractions, pH, CO3 2-, organic carbon and total arsenic content in the surficial sediments of six different zones of the Urías lagoon. Sand was the dominant size fraction throughout the whole system. The highest organic matter and the lowest pH values were found in adjacent sites to industrial activities, especially to fish processing. Most arsenic concentrations were within the values of the natural local background (12.6-27.3 mg/kg), with the possible exception of sediments close to the industrial area, especially those nearby the fish processing plants, where the mean As (45.2 ± 9.3 mg/kg) exceeded the level which may have adverse effects on marine organisms (41.6 mg/kg). However, it is not excluded that such levels are results rather from the combined effect of the hydrodynamic and sediments dynamic of sediment associated to local enrichments background of the region. Palabras clave: lagunas costeras, sedimentos, elementos traza, Golfo de California RESUMEN La laguna costera Urías se encuentra rodeada por la zona urbana de Mazatlán (noroeste de México). Con la finalidad de detectar posibles impactos de actividades humanas sobre las características de los sedimentos, se determinaron los porcentajes de las fracciones particuladas, pH, CO3 2-, carbono orgánico y arsénico total en los sedimentos Short communication / Comunicación breve