| Antimony (Sb) and arsenic (As) are naturally occurring elements, often found in soils and sediments. Arsenic has been of great interest due to its toxicity and geochemical behavior. Transformation and transport of As have been studied by many researchers. Limited information on the behavior, transformation and transport of Sb in aquatic systems is available. Also, information on Sb speciation and total content in different media is scarce and often contradictory. The potential mobility of Sb at the sediment-water interface is unknown Natural sediment concentrations for both elements can be increased in localized areas due to anthropogenic activities, such as the case of Manadas Creek, an urban tributary of the lower Rio Grande. Manadas Creek is located in an industrialized area of Laredo, a semi-arid region of TX, where warehouses, a major railway line and a decommissioned Sb smelter are located. Previous studies have found contamination of the creek water with heavy metals such as Sb and As. In this study, water and sediment samples were collected in Manadas Creek during 2008. Results present spatial distribution of Sb and As in this creek during a dry season and their seasonal/temporal variation. Small-scale desorption experiments and large-scale flume experiments were also performed to examine Sb and As release from the bed sediments in the laboratory. It is expected that these results will provide insights into the fate and transport patterns of antimony and arsenic in a semi-arid creek located in South Texas, which will have valuable implications to other similar aquatic systems around the world. |
