HEAVY METALS ON TRAILS AND MINE DUMPS, JACOB CITY, TOOELE CO, UTAH

Jacob City is an abandoned mining town in the Ophir Mining District, near Stockton, UT. The area has many abandoned mines, waste rock and tailings piles that are part of a system of all terrain vehicle (ATV) trails with regular visitation. These mine dumps have high concentrations of heavy metals and may pose a health risk to ATV users. Soil samples were tested with an x-ray fluorescence analyzer and results show soils in the recreational area have high levels lead, arsenic, and cadmium exceeding the Bureau of Land Management risk-based screening criteria (BLM criteria; lead 1,000 mg/kg, arsenic 300 mg/kg and cadmium 950 mg/kg) for ATV users: lead (n=37, range 108 to 115,900 mg/kg, x 16,091 mg/kg), arsenic (n=36, range 0 to 6,732 mg/kg, x 1,166 mg/kg) and cadmium (n=25, range 0 to 1,626 mg/kg, x 87 mg/kg). Concentrations of lead, arsenic, and cadmium correlate with munsell soil color system hue on tailings piles, waste rock piles and ATV trails: lead is elevated in soil with 5YR and 7.5YR hues, arsenic is elevated with 5YR and 7.5YR hues, while, cadmium is elevated with a 2.5Y hue. The data show that high concentrations of cadmium are inversely related to high concentrations of lead and arsenic. When cadmium is high, lead and arsenic are lower; and when lead and arsenic are high, cadmium is lower. Findings also show that average lead (x of lead in dumps 20,434 mg/kg, along trails 8,038 mg/kg) and arsenic (x arsenic in dumps 1451 mg/kg, along trails 642 mg/kg) concentrations are higher on mine dumps compared to ATV roads. Average cadmium concentrations (x cadmium in dumps 109 mg/kg, along trails 166 mg/kg) are higher on ATV roads compared to mine dumps. The cause of this pattern is still being explored. Since color hues correlate with elevated levels of heavy metals at the study area, color hue could be used as a proxy for elevated levels of heavy metals. This color proxy could be used to caution ATV users and assist future mapping and environmental remediation.