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Dredged Materials Management -Minnesota Pollution Control Agency Grain Size Analysis Page 3 of 10 Begin the dredge site evaluation by determining whether the material to be dredged is predominantly sand, gravel or pebble, or is comprised of other materials. Dredge material that is predominantly sand, gravel or pebble is unlikely to be contaminated, as pollutants do not generally adhere to these types of particles, and are therefore not incorporated into the sediment. Dredge materials that are shown to be more than 95% sand are unlikely to be contaminated and do not require additional chemical evaluation, and can proceed to permitting. Refer to Chapter 4 of the guidance manual for specifics on this process and reporting parameters. Past Industrial Pollutants Complete an examination of any historical records, data or maps that illustrate current and past land uses on the surrounding watershed, as well an examination of any existing sediment data or information pertaining to the project site. Performing this evaluation helps to identify the list of analytes that need to be tested by focusing only on pollutants that have a reasonable Iikelihood of being present in the sediment. Based on the evaluation of historical land uses and the reasonable likelihood far pollutants in the sediment to be dredged (see Chapter 3 of the guidance manual), analysis of analytes beyond the baseline analytes, as described below, maybe required. Sampling and Analysis of Pollutants Dredged material not excluded from additional analysis, as determined using the grain size analysis, must be analyzed for at least the analytes listed in the table below. Additional analytes identified by the past industrial pollutant evaluation, above, should also be analyzed. Additional analytes to considered are listed in Table 4 of Chapter 4 in the guidance manual. For details on collecting samples and making a determination of which analytes need to be sampled, refer to Chapters 3 and 4 of the guidance manual. Baseline Sediment Parameter List Parameter Analytical Method Method Detection Limit (dry weight) Inorganics-Metals Arsenic SW-846 30506/60106 EPA 6010 or 7060 0.42 mg/kg Cadmium SW-846 30506/60108 EPA 7131 0.02 mg/kg Chromium III SW-846 30506/60106 EPA 6010 or 7191 0.058 mg/kg Chromium VI SW-846 30506/60106 EPA 6010 or 7191 0.058 mg/kg Copper SW-846 30506/601 OB EPA 6010 or 7211 0.1 mg/kg Lead SW-846 30506/60106 EPA 6010 or 7421 0.22 mg/kg Mercury SW-846 7471A EPA 7471 0.02 mg/kg Nickel SW-846 30506160106 EPA 6010 0.36 mg/kg Selenium SW-846 30506160106 0.43 mg/kg Zinc SW-846 30506/60146 EPA 6010 or 7951 0.35 mglkg Inorganics-Nutrients http://www.pca. state.mn. us/water/dredgedmaterials.html 11 /20/2Q08