Master of Science in Biology (MS)
Manadas Creek is an urban tributary of the Rio Grande that flows past a decommissioned antimony smelter. This smelter is associated with the heavy metal contamination in the creek and still poses a threat to the surrounding aquatic environment. With concerns on the rise of metal pollution, the biomonitor, the Asiatic clam (Corbicula fluminea) was used to determine bioaccumulation from the water column and sediments in Manadas Creek. The metals arsenic (As), antimony (Sb) and thallium (Tl) were analyzed in the water, sediments, gills, mantle, foot, digestive (DI) tract, gonads and shell of clams collected from sites between March to August 2013. Metal analysis of arsenic, antimony and thallium was performed by ICP-OES. High levels of antimony, arsenic and thallium in the water (13.45±6.65; 10.33±3.4; 7.47±1.73) and sediments (75.77±1.59; 6.41±1.19) at the site downstream from the smelter were observed. Additionally, tissue samples from this site had the highest concentrations, however there was no direct correlation between the metal concentrations in the water column and sediments with the tissues. There were no detectable concentrations of arsenic, antimony and thallium in shell samples. Site 3 had the highest thallium concentration in the sediments (3.00±0.68). No detectable thallium concentrations were detected in the tissues. Based on the results, the organotropism for arsenic is DI tract > gills > gonads > foot > mantle > shell and the organotropism for antimony is gills > DI tract > gonads > mantle > foot > shell. The Asiatic clam (Corbicula fluminea) is a useful biomonitor to provide data on the status of metal pollution in Manadas Creek, Laredo, Texas.
Garcia, Natasha, "The Asiatic clam (Corbicula fluminea) as a bio-monitor for determining the distribution of antimony, arsenic and thallium in the water column and sediments of Manadas Creek, Laredo, Texas" (2016). Theses and Dissertations. 40.