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Standard Operating Procedure Measurement of Potassium Permanganate SOxD SOxD analysis using potassium permanganate provides an estimate of the soil oxidant demand for potassium permanganate. The potassium permanganate soil oxidant demand ( SOxD) is measured using a small representative sample of soil, a standard potassium permanganate solution, and an Ultra Violet Visible detector (UV-vis) or spectophotometer to measure the permanganate concentration in the treatment water over time. The method is presented below: Triplicate blank samples or controls: Add 30ml KMn04 standard solution ( 0. 500 g/L) to each of 3 amber VOA bottles Triplicate samples of each soil sample: Add 1g soil to each amber VOA bottle Add 30ml KMn04 standard solution ( 0. 500 g/L) Vortex bottles for 30 seconds Allow samples to stand for 15 minutes before reading in the UV-vis spectrophotometer The analysis can be scaled up using equivalent proportions. If a larger sample is required, 1 kilogram (kg) of soil can be used with 10 liters of KMn04 solution. Mixing will have to be done by hand or using a sample roller. The efficiency of mixing will depend on the containers available to do the mixing in. Analysis of Samples Dilute samples 1 /10 to 1 /100 for analysis ( ie. 100 ul sample in 10ml distilled water) depending on the intensity of the color in the reacted solution. Use a 10ml pipette to dispense 10ml distilled water into a clean VOA bottle. Add the sample, put on the lid, inverted twice and pour the diluted sample into the HACH UV-vis spectrophotometer tube. If precipitate is observed in the extracted sample and the standard used for analysis, filter the sample with a 0. 45 pm filter cartridge or centrifuge at high speed prior to analysis. Set up a standard concentration curve with the standard solution prepared to treat the samples. Prepare standards that are between 0 and 500 mg/I of KMn04 to quantify the KMn04 in each sample. Wipe each tube with a Kimwipe if necessary. Both VOA bottle and spectrometer tube should be rinsed between sample sets, but not between replicates of the same set. Sampling Intervals Samples that contain high concentrations of organic matter or clay will have a large soil oxidant p 9 demand. Typical soil samples that have low organic matter and low or moderate clay concentrations consume oxidant at a more moderate rate. The permanganate solution in samples should be analyzed immediately after addition, within several hours, and after 1 , 2, 4, 7 , and 10 days. After approximately ten days the consumption rates have stabilized and the total soil oxidant demand can be estimated from the results. Samples should be kept in the dark (in the VOA bottle box) Samples should be shaken/vortexed after each analysis. DATA MANIPULATION AND CALCULATIONS The concentration of KMn04 in the sample is determined from the UV-vis analysis. Multiply the observed concentration by the dilution factor to get the sample concentration. Subtract the solution concentration from the initial concentration ( 3.95 g/L or 3950 mg/L) and multiply the total volume used per sample ( 10 mL or 0. 10 L according to the method above) times the difference. Plot the loss I:\BP-ARC0\04 BP Valley Portfolio\BP Valley Sites\2130\Work Plan\2130 workplan 2-07.doc