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waste. Note that there are not any proposed regulations, even internally, about SPLP legislation. <br />Lower cleanup levels will be associated with the use of the SPLP since these represent more <br />realistic conditions. The use of the SPLP procedure will assist in protecting groundwater if on- <br />site disposal is performed since this method was designed for that specific purpose. <br />Using the TCLP extraction procedure to evaluate the effectiveness of treatment, usually results in <br />the untreated materials being analyzed with LF 1 and the treated materials being analyzed with <br />LF 2. As previously discussed, LF 1 is utilized for materials with a lower buffering capacity. <br />After the addition of treatment reagents such as Portland cement, fly ash, cement kiln dust and <br />hydrated lime, the buffering capacity of the untreated material is increased and therefore, LF 2 is <br />often used for the extraction procedure. This can in effect result in higher leachable <br />concentrations in the treated materials than in the untreated materials since the leachability of <br />metals is highly correlated with the pH of the leaching fluid. For example, lead is least soluble at <br />pH values ranging from 7 to 9. Once the pH of the matrix becomes either higher than 9 or lower <br />than 7, the leachability of lead can increase dramatically. Therefore, maintaining the pH of the <br />leaching fluid between 7 and 9 becomes an important factor in the effectiveness of stabilization <br />treatment. <br />The advantage of the SPLP extraction procedure is that one leaching fluid is utilized for the site <br />both before and after treatment since the leaching fluid is determined by the region of the country <br />that the site is in and not by a pH determination test. This provides for a better interpretation of <br />the actual effectiveness of treatment since the same leaching fluids can be utilized both before <br />and after treatment. Treatment designs can be developed in an effort to maintain pH values at it <br />level that provide for the least amount of leachability of the contaminants of concern. <br />The SPLP extraction procedure n-tore closely resembles worst case anticipated site conditions <br />than does the TCLP extraction procedure since the SPLP procedure is based on actual rainfall <br />conditions for that particular region of the country. However the TCLP procedure, which is <br />based on leaching that may occur in a sanitary landfill does not always represent conditions <br />present at the particular location that is being treated. Additionally, since the SPLP procedure <br />takes into account the leaching in a particular region of the country associated with acid rain, a <br />worst-case scenario is evaluated. This allows treatment designs to be developed that will in <br />effect be successful at reducing leachable contaminant concentrations under the most unfavorable <br />conditions at the site. 'T'herefore, it can be confirmed that the treated material is more protective <br />of human health and the environment. <br />Treatment of contaminated materials often relies on different approaches when utilizing the <br />TCLP and SPLP extraction methods. Treatment effectiveness through the use of the SPLP rather <br />than the TCLP is not necessarily easier to achieve, but rather treatment effectiveness varies from <br />site to site. Historically, the SPLP extraction procedure has been used to evaluate metals <br />contamination as previously discussed. However, the SPLP extraction procedure is gaining <br />increased acceptance for organic analyses in addition to metals analyses, since the infiltration of <br />acid rain provides a better representation of site conditions than contact with organic acids such <br />as those used in the TCLP extraction procedure. <br />In conclusion, the use of the SPLP extraction procedure is becoming more popular for use in