INITIAL TRACE ELEMENT AND POLLUTION ANALYSIS OF ROAD SEDIMENT ASSOCIATED WITH THE AES POWER PLANT, GUAYAMA, PUERTO RICO

Road sediments have the potential to accumulate heavy metals and other toxic pollutants that come from vehicular emissions, tire and brake wear, pavement degradation, and other man-made sources. Ten (n=10) Road sediment samples were collected from areas near an industrial power plant site, AES Power Plant, Guayama, Puerto Rico in order to evaluate potential contaminant exposure. Metal concentrations were observed to overlap between upper continental crust values to well above, indicating some level of pollution is observed. Metals of most environmental concern varied in concentration and include V (94 to 157 ppm), Cr (61 to 283 ppm), Co (13 to 21 ppm), Ni (32 to 191 ppm), Cu (31 to 63 ppm), Zn (92 to 190 ppm), As (2 to 4 ppm), and Pb (3 to 15 ppm). Ni and Cr show a strong positive correlation (r² = 0.94, p<0.001) suggesting a linked source. Pronounced correlations between siderophile elements and Fe were not observed. Pb, Cu, and Zn did not show strong correlations. Poor correlations contrast with other studies of road sediment from the central U.S.. They may reflect mobilization or mixing processes that are different in Puerto Rico owing to climate and precipitation. Concentrations of nickel, chromium, and vanadium were concerning in some samples. X-ray diffraction analysis showed the samples were dominated by quartz, with lesser amounts of carbonates and feldspars, and suggest a strong influence from mafic rocks is not present. Further geochemical analysis and comparison to environmental background are ongoing. Overall, this study indicates potentially elevated exposure risks from road sediments near the power plant, and that road sediments are an understudied environmental medium in Puerto Rico. Characterizing contaminants in road dust and sediments provides important information about exposure hazards in areas where people live, work, and play. Additional research on road sediment in the broad southern region of Guayama, Puerto Rico should be conducted. This study may provide useful data and analysis for land management and public health evaluation.