2012-01-06_PERMIT FILE - C1982057 (18)

Home Browse Search

19811. Normal plant available nickel concentrations in soil are slightly less than 2 ppm (Barth et al., 19811. Zinc. Zinc is a necessary component of several enzyme systems which regulate various metabolic activities within plants. Adequate zinc levels are essential for normal cell division, root growth, seed production, protein metabolism, and auxin formation (Tiedemann and Lopez, 19821. For normal growth, most plants generally require a minimum zinc concentration of 1 ppm while zinc related toxicity occurs at about 70 ppm. The potential for zinc deficiency is increased by many factors including but not limited to high pH, high lime rates, high phosphorous levels, and high concentrations of other metallic nutrients ICu, Fe, and Mnl. Zinc toxicity is more of a concern on acid soils because of the higher solubility of zinc on acid soils. The antidote for zinc toxicity is the application of lime (Traynor, 1 9801. Cadmium. Cadmium is a non-essential metallic element that is used in industry. Plant toxicities due to elevated levels of cadmium under natural conditions or in reclamation are unlikely (Barth et al., 1981 and Munshower, 19831. Mercury. Mercury predominantly exists in an inorganic form which is not absorbed readily by plants. There have been no documented cases of mercury toxicity to plants or to animals under normal conditions. Mercury toxicity is limited to industrial or agricultural situations where mercuric fungicides or other contaminants are used (Barth et al., 1981 and Munshower, 1983). Lead. This is anon-essential Ito plant and animal life) heavy metal that could induce plant toxicity symptoms if present in excess quantities. As the pH decreases, the solubility and the potential for lead toxicity increases. In most soils of the Great Plains, lead is complexed and not readily leached to ground water nor available for plant uptake (Barth et al., 1951 and Munshower, 19831. Arsenic. Munshower (19831 states that toxic concentrations of arsenic in natural soils and overburden have never been reported. Barrett and others (1980) stipulate that toxicity is confined to soils which have accumulated arsenic through foliar spray compounds. The arsenates are fixed by soils in a relatively insoluble state and are not lost by leaching. The critical water-soluble arsenic concentration in soils is 2 ppm (USDA, 19571• Aluminum. Aluminum is a non-essential metallic element that could induce plant toxicity symptoms if present in excess quantities. Although aluminum is the third most abundant element in the earth's crust, it is typically available for plant uptake in only trace amounts in alkaline soil (Traynor, 19801. Like other heavy metals, the aluminum concentration in the soil solution increases as the soil becomes more acid, In extremely acid soils, aluminum is released from the crystal lattice of clay minerals to cation exchange sites and into the soil solution PR03 14 Revised 07/02