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al., 1981 and Munshower, 1983). Lead concentrations of overburden and <br />interburden material from Phase I samples never exceeded 10 ppm (Tables <br />6-6 and 6-7; Figures 6-3 and 6-7). This is an order of magnitude less <br />than what is considered to be excessive. No additional lead analyses <br />are warranted at Nucla Kline. <br />Zinc. For normal growth, most plants generally require a minimum zinc <br />concentration of 1 ppm while zinc related toxicity occurs at 70 ppm. <br />Mears zinc levels of overburden and interburden material (for Phase I <br />samples) are 4.9 and 4.7 ppm, respectively; slightly above deficiency <br />levels and well below excessive (Tables 6-6 and 6-7; Figures 6-3 and <br />6-8). Twinned sample results from recored offset hales for sites 695E <br />and 697E presented in Appendix 6-4 showed that the initial samples were <br />contaminated. No additional zinc analyses are justified for Nucla <br />Mine. However, zinc analyses were highly recommended for site 873E <br />during Peabody's April 10, 1986 meeting with CMLRD. Therefore, zinc <br />analyses were completed on all samples collected from site 873E. <br />Nickel. Nickel toxicity problems are restricted to poorly drained very <br />acid soils, soils derived from serpentine parent materials or soils that <br />have been contaminated near smelters (Munshower, 1983 and Barth et al., <br />1981). Normal plant available nickel concentrations in soil are <br />slightly less than 2 ppm (Barth et al., 1981). Overburden and <br />interburden nickel concentrations in Phase I samples collected at Nucla <br />Mine were 1.0 and 1.5 ppm respectively (Tables 6-6 and 6-7). All nickel <br />values were well below toxicity levels (Figures 6-3 and 6-8). No <br />additional nickel analyses are warranted at Nucla Mine. However, nickel <br />analyses were highly recommended for site 873E during Peabody's April <br />10, 1986 meeting with CMLRD. Consequently, nickel analyses were <br />completed on all samples collected from site 873E. <br />Manganese. fanganese toxicities have been documented in poorly-drained <br />alkaline soils and extremely acidic soils with pH levels below 5.0. <br />Manganese concentrations at Nucla are generally less than 30 ppm but <br />• were higher in the more acidic interburden at site 2C (Tables G-6 and <br />6-7; Figures 6-3 and 6-8). A manganese value of 107 ppm was also <br />recorded for the 15 to 20 foot sample increment at site 3C. This site <br />is located outside of the projected mine disturbance area. Manganese <br />6-34 Revised 3/6/87 <br />