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as `low level hazardous waste' if the toxicity characteristic leaching procedure/synthetic <br />precipitate leachate procedure(TCLP/SPLP) test result exceeds 0.20 mg/L. Any soil exceeding <br />state or federal hazardous waste criteria would require disposal in a specified hazardous waste <br />landfill. The EPA has set regulatory levels that can be used to compare to SPLP results to <br />determine whether the measured constituent levels occur at potentially toxic levels (`toxic' is <br />defined as an element exceeding the regulatory limits for contaminants under the TCLP/SPLP <br />test analysis 40 CFR § 261.24). These values are shown in Table 5. <br />The EPA has also established toxicity thresholds (or preliminary remediation goals) protective <br />of various types of human health receptors (residential, industrial, construction worker). These <br />values are screening guidelines intended as tools for evaluating contaminated waste sites. <br />Concentrations above a threshold do not necessarily designate a site as contaminated, but may <br />warrant further evaluation of potential risks. The `solid' or soil thresholds for metals are <br />summarized in Table 6 and were compared to the 2009 waste rock solid analysis results. <br />Acid-Base Accounting (ABA) was developed at West Virginia University as an approach at <br />classifying mine spoils for revegetation potential based on acidity, alkalinity and rock type. The <br />importance of acid neutralizing minerals was recognized and quantified. ABA analysis of a <br />sample consists of two measurements: 1) measurement of the amount of acidity a sample is <br />likely to produce (acid generation potential), 2)measurement of the inherent neutralization <br />potential of the same sample (acid neutralization potential). The difference between these two <br />measurements is defined as the net balance quantified as the Acid Base Potential (ABP) <br />measure (refer to Table 3). <br />o The `AGP' -acid generation potential represents the stoichiometrically quantified <br />amount of total sulfur available to form acid expressed in units of ppt CaC03. <br />o The ANP- acid neutralization potential represents the stoichiometrically <br />calculated neutralization potential of a material in the same units. <br />o The ABP-acid base potential is the net balance calculated by the subtraction of <br />AGP from ANP [ANP - AGP = ABP]. <br />The ABA parameters are all conservatively derived using `total sulfur' measures. A more <br />realistic interpretation would rely upon the use of pyritic sulfur. For the purposes of this <br />assessment, both total sulfur and pyritic sulfur-derived ABA (refer to Table 4) parameters were <br />relied upon. <br />If ANP is > than AGP, the resulting ABP will be a positive number. If ANP is < AGP then ABP <br />will be negative. The ANP/AGP ratio is also used to describe the acid-producing potential of the <br />tested material. A negative ABP or a ANP/AGP ratio < 1 indicates a potential for a mine waste to <br />form acid (EPA, 1994)• There are no `regulatory levels' applicable to ABA analysis results, <br />however the literature (inclusive of EPA and State regulatory agencies) provides limits useful for <br />the interpretation of ABA results (Table 7). For instance, the first attempts to define levels of <br />. _ <br />7 1 P a g e