New Mexico Geological Society Annual Spring Meeting — Abstracts

The Graphic Smelter (now referred to as Cuba Smelter) is located on the southeast side of Socorro and lies between Interstate Highway 25 and Cuba Road. Itwas first opened in 1912, and was in operation intermittently until World War I. Upon the extraction of lead, gold, and silver from the ore, lead was released in the form of airborne particulate matter and settled out in the surrounding area, thereby contaminating the soil. Further contamination was produced along the highway as a result offumes produced by the leaded gasoline used in automoI biles. This contamination poses a possible threat to the health of those who live near the smelter, particularly downwind of the slag pile.

To determine the location of the lead contamination, soil samples from the surrounding area were collected and analyzed. These samples were taken from the top 1-2 inches ofmaterial, were fractionated into sand-, silt-, and clay-size fractions, and determinations for the lead in each sample by size fraction were established by wet chemistry followed by atomic absorption analysis. Results thus far are in agreement with those produced by the New Mexico Environmental Improvement Division. The Environmental Protection Agency is also assessing the area to determine the necessity of temporary cleanup of the site using methods similar to those used for the Billing Site (located west of the Graphic Smelter in Socorro). Samples analyzed have higher lead values in the clay-sized material (ranging from 430 ppm to 12,900 ppm) than in the sand-sized material ( ranging from 47 ppm to 10,000 ppm), and the lead values for the silt-sized material are well below 500 ppm. On the average, clay-sized material composed approximately 4 percent of the total sample, whereas sand composed approximately 64 percent, and silt composed approximately 32 percent.

These results indicate a high level of lead contamination near the slag pile and the surrounding area. While samples taken further away from the slag pile show relatively high concentrations oflead in the clay-sized fraction, lower concentrations are found in the sand-and silt-size fractions than those nearer the slag pile, possibly indicating further contamination from the highway. Further work is being done to determine the effects of the highway versus those of the Cuba Smelter.