Session: Undergraduate Research Posters: Analytical Chemistry:

The contamination of chemical pollutants in the Rio Grande River water and sediments has been an ongoing issue on both sides of the Texas-Mexico border posing a public health risk. The purpose of this study was to analyze the surface water collected from thirteen different sites of the Rio Grande River Basin in the Texas-Mexico border region between Amistad Reservoir, Texas, and Brownsville, Texas for total metal content. The analysis was performed using Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) following the standard EPA method 200.8 in order to assess the current metal distribution patterns in the region. The Texas sites selected were Amistad Reservoir, Del Rio, Eagle Pass, Laredo/Columbia, Cenzio, San Igancio, Zapata, Falcon, Roma, Mission, Rio Grande City, McAllen, and Brownsville. The water samples collected were acidified on-site with nitric acid (1+1) and hydrochloric acid (1+1), filtered in the lab through a 0.45 µm filter followed by digestion between 93-96 °C, and analyzed for 27 metal ions by ICP-MS using a Bruker model 820 MS ICP-MS. The results of the analysis were compared to EPA limits for surface water. The percent recovery for these metals in the spiked control samples ranged between 96% and 110%. The results show an elevated concentration of lead, a toxic heavy metal, of 0.041 mg/L in Amistad Reservoir that was above the federally regulated EPA limit of 0.015 mg/L lead for surface water. The remaining metals analyzed in the water samples from these thirteen sites were within the permissible limits of the EPA and the State of Texas Commission on Environmental Quality standards.

Sara J Ibarra

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