Contaminant Surrogate Analysis

Most hazardous waste sites and facilities contain tens to hundreds of chemicals. The process of collecting data can therefore be overwhelming and is sometimes unrealistic. However, risk at a 

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In case of hydrophobic compounds, which strongly adsorb to particles, e.g. pentabro-modiphenylether or 5 and 6 ring polycyclic aromatic hydrocarbons, special care is required to ensure complete extraction of the particle bound fraction. Separate analysis of SPM and of the liquid would be a good option. If it can be justified, for example, by consideration of contaminant partitioning, analysis of the SPM fraction as surrogate for whole water might be appropriate. Nevertheless, in water bodies with extremely low SPM content (<3mg/L) the dissolved fraction of those contaminants contributes significantly to the total concentration, and hence, has to be taken into account. 

For the purposes of this example, it was assumed that the waste was placed 4 m deep and covered with a cap and soil that was at least 3 m thick. As a consequence, the assumed scenario was an onsite drilling event. The dose analysis assumes a two-fold volume increase (50 percent dilution) of the drill tailings by uncontaminated material. The mixture of waste and uncontaminated cover material is spread on the surface of the site, and individuals working in the area are exposed to the tailings for 1,000 h. The thickness of the layer of contaminated drill tailings is assumed to be about 5 cm and the area to be about 3.3 m2. Using dose as a surrogate for risk, analysis of this scenario yields a dose of0.002 mSv from all radionuclides. Since the assumed allowable dose is 20 mSv (see Table 7.1), the risk index would be 0.002/20 = 10 4, which is well below the value of unity, and the waste would be classified as low-hazard. 

Several papers investigated the use of SPME for VFA analysis in wastewater and in air. Briefly, a fiber is exposed to the sample headspace or inserted directly into the sample. Analytes adsorb onto the fiber and are subsequently desorbed at high temperatures in the GC injection port. SPME is a solvent-free technique which introduces less potential contaminants into the GC compared to direct injections. SPME is also rapid since no further sample preparation steps are required. It may be used for routine analysis provided that the specific autosampler required for this method is available and that the optimized method conditions are suitable for autosampler application. Further information on principles and other applications of this technique can be found elsewhere. " " Parameters which have been optimized for VFA analysis are fiber coating, fiber exposure time, sample temperature, sample pH, sample agitation, potential salt addition, and desorption parameters. Surrogate standards employed for VFA analysis were 2-ethylbutyric acids for GC/FID or GC/MS and C-labeled organic acids for GC/MS. The method was optimized using standards in deionized water and only a few wastewater samples were analyzed as examples. 

Erickson, R.P. Tripathi, A. Maswadeh, W.M. Snyder, A.P. Smith, P.A., Closed tube sample introduction for gas chromatography-ion mohihty spectrometry analysis of water contaminated with a chemical warfare agent surrogate compound. Anal. Chim. Acta 2006, 556, 455 61. 

Studies of the source of exposure to PFCs have rarely been conducted. Thus, studies of the source of contamination with PFC, the source of exposure, the difihision path, the accumulated form, and toxicity are necessary. Currently, environmental contaminant of PFCs were mainly reported in polluted mud, ° environmental water, ° and atmosphere. However, the concentrations of detected PFCs are extremely low, and it is not sufficient to evaluate them as an exposure source. Therefore, we focused on house and carpet dust, ° which exists in our daily lives and contains many chemicals, to clarify the source of e xisure to PFCs, and discussed a highly sensitive and accurate method for the analysis of PFCs in house and carpet dust. The analytes were PFOS, PFOA, PFNA, and PFHxS, which are frequently detected in human blood, and surrogate standards were C4-PFOS and Cx-PFOA. The supercritical fluid extraction (SFE) method was used for house and carpet dust. Effective extraction is expected when supercritical liquid is used as the extraction solvent, as the elution ability of supercritical liquid is similar to that of conventional liquid and supercritical fluid can permeate every comer of the sample, as air does. 

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