Trichloroethylene sampling

Figure 8. Trichloroethylene sampling data T == 298 RH = 80% P -= 760 mm concentration = 990 ppm from section (O) backup section...

Welding (qv) of titanium requires a protected atmosphere of iaert gas. Furthermore, parts and filler wire are cleaned with acetone (trichloroethylene is not recommended). The pieces to be welded are clamped, not tacked, unless tacks are shielded with iaert gas. A test sample should be welded. Coated electrodes are excluded and higher purity metal (lower oxygen content) is preferred as filler. Titanium caimot be fusion-welded to other metals because of formation of brittle intermetallic phases ia the weld 2oae. 

A 5 wt.% CoOx/Ti02 catalyst gave the most promising activity for continuous catalytic wet oxidation of trichloroethylene at 310 K with a unsteady-state behavior up to 1 h. The catalyst after the oxidation possessed a Co 2p3/2 main peak at 779.8 eV, while the peak was obtained at 781.3 eV for a fiosh sample. Only reflections for C03O4 were indicated for these samples upon XRD measurements. The simplest model for nanosized C03O4 particles existing with the fi"esh catalyst could reasonably explain the transient activity behavior. 

Analytical Methods for Determining Trichloroethylene in Environmental Samples... 

A study using skin samples from healthy humans revealed that trichloroethylene extracts lipids from the stratum comeum (Goldsmith et al. 1988). The study indicates that lipid extraction is the reason for whitened skin following exposure to solvents such as trichloroethylene. 

Differences among individuals can partially explain the differences in the before workshift and end of workshift levels of trichloroethylene and its metabolites. Increased respiration rate during a workday, induced by physical workload, has been shown to affect levels of unchanged trichloroethylene more than its metabolites, while the amount of body fat influences the levels of the solvent and its metabolites in breath, blood, and urine samples before workshift exposure (Sato 1993). Additionally, liver function affects measurements of exhaled solvent at the end of workshift increased metabolism of trichloroethylene will tend to decrease the amount exhaled after a workshift. Increased renal function would affect levels of TCA and trichloroethanol in blood before a workshift in the same way, but it probably would not affect urine values between the begiiming and the end of the workshift because of the slow excretion rate of TCA. 

Trichloroethylene has been detected in a number of rainwater samples collected in the United States and elsewhere (see Section 5.4.2). It is moderately soluble in water, and experimental data have shown that scavenging by rainwater occurs rapidly (Jung et al. 1992). Trichloroethylene can, however, be expected to revolatilize back to the atmosphere after being deposited by wet deposition. Evaporation from dry surfaces can also be predicted from the high vapor pressure. 

Data gathered from several sites near Niigata, Japan, between April 1989 and March 1992 showed elevated levels of trichloroethylene and other volatile chlorinated hydrocarbons in the winter (Kawata and Fujieda 1993). A rural site in this study had armual mean concentrations between 0.17 and 0.32 ppb, while four industrial sites had mean concentrations between 0.029 and 4.8 ppb. The average trichloroethylene level detected in samples collected from ambient air in the Norwegian Arctic between 1982 and 1983 was 0.007 ppb (Hov et al. 1984). Average concentrations of trichloroethylene in Alaskan Arctic haze between 1980 and 1982 were 0.036 ppb in winter and 0.007 ppb in summer (Khalil and Rasmussen 1983). 

A summary of U.S. groundwater analyses from both federal and state studies reported that trichloroethylene was the most frequently detected organic solvent and the one present in the highest concentration (Dyksen and Hess 1982). Trichloroethylene was detected in 388 of 669 groundwater samples collected in New Jersey from 1977 to 1979, with a maximum concentration of 635 ppb (Page 1981). Maximum concentrations ranging from 900 to 27,300 ppb trichloroethylene were found in contaminated wells from four states (Pennsylvania, New York, Massachusetts, and New Jersey) (Burmaster 1982). 

A possible source for much of the groundwater contamination is landfill leachate containing trichloroethylene. Trichloroethylene was the most commonly found chemical at NPL sites in New York State (Mumtaz et al. 1994). The compound was detected in leachate samples from Minnesota municipal solid waste landfills at levels ranging from 0.7 to 125 pg/L (0.7-125 ppb) and in groundwater near landfills at levels ranging from 0.2 to 144 pg/L (0.2-144 ppb) (Sabel and Clark 1984). Trichloroethylene was also detected in landfill leachate from a landfill in New Jersey at concentrations of up to 7,700 pg/L (7,700 ppb) (Kosson et al. 

An analysis of the EPA STORET Data Base (1980-1982) found that trichloroethylene had been positively detected in 28% of 9,295 surface water reporting stations nationwide (Staples et al. 1985). An analysis of 1,350 samples taken from 1978 to 1979 and 4,972 samples from 1980 to 1981 from the Ohio River system found a similar percentage of positive detections most positive samples had trichloroethylene levels of... 

Trichloroethylene in soil and groundwater were found to be correlated (r 0.9994) in samples taken during well instillation at the U.S. Army Cold Regions Research and Engineering Laboratory in Hanover, NH (Hewitt and Shoop 1994). Concentrations of trichloroethylene in soil from the saturated zone were 0.008-25 mg/kg, while concentrations in the groundwater were 0.044-180 ppm. 

Trichloroethylene has been detected in dairy products (milk, cheese, butter) at 0.3-10 pg/kg (0.3-10 ppb), meat (English beef) at 12-16 ppb, oils and fats at 0-19 ppb, beverages (canned fruit drink, light ale, instant coffee, tea, wine) at 0.02-60 ppb, fruits and vegetables (potatoes, apples, pears, tomatoes) at 0-5 ppb, and fresh bread at 7 ppb (McConnell et al. 1975). Samples obtained from a food processor in Pennsylvania contained trichloroethylene concentrations of 68 ppb in plant tap water, 28 ppb in Chinese-style sauce,... 

An analysis of six municipal solid waste samples from Hamburg, Germany, revealed levels of trichloroethylene ranging from undetectable to 0.59 mg/kg (Deipser and Stegmaim 1994). In a study analyzing automobile exhaust for chlorinated compounds, trichloroethylene was not detected (Hasanen et al. 1979). 

Correlations of exposure with other measures of body burden are often difficult and their results are consequently less conclusive. For example, trichloroethylene was present at unspecified levels in eight of eight samples of mother s milk from four urban areas in the United States (Pellizzari et al. 1982). Whole-blood specimens from 121 men and 129 women with no known exposure to trichloroethylene had levels from nondetectable to 1.5 ppb (Antoine et al. 1986). Post-mortem analyses of human tissue revealed body fat... 

As part of the Third National Health and Nutrition Evaluation Survey (NHANES 111), the Environmental Health Laboratory Sciences Division of the National Center for Environmental Health, Centers for Disease Control, will be analyzing human blood samples for trichloroethylene and other volatile organic compounds. These data will give an indication of the frequency of occurrence and background levels of these compounds in the general population. 

The purpose of this chapter is to describe the analytical methods that are available for detecting, measuring, and/or monitoring trichloroethylene, its metabolites, and other biomarkers of exposure and effect to trichloroethylene. The intent is not to provide an exhaustive list of analytical methods. Rather, the intention is to identify well-established methods that are used as the standard methods of analysis. Many of the analytical methods used for environmental samples are the methods approved by federal agencies and organizations such as EPA and the National Institute for Occupational Safety and Health (NIOSH). Other methods presented in this chapter are those that are approved by groups such as the Association of Official Analytical Chemists (AOAC) and the American Public Health Association (APHA). Additionally, analytical methods may be included that modify previously used methods to obtain lower detection limits and/or to improve accuracy and precision. 

Several methods are available for the analysis of trichloroethylene in biological media. The method of choice depends on the nature of the sample matrix cost of analysis required precision, accuracy, and detection limit and turnaround time of the method. The main analytical method used to analyze for the presence of trichloroethylene and its metabolites, trichloroethanol and TCA, in biological samples is separation by gas chromatography (GC) combined with detection by mass spectrometry (MS) or electron capture detection (ECD). Trichloroethylene and/or its metabolites have been detected in exhaled air, blood, urine, breast milk, and tissues. Details on sample preparation, analytical method, and sensitivity and accuracy of selected methods are provided in Table 6-1. 

Headspace analysis has also been used to determine trichloroethylene in water samples. High accuracy and excellent precision were reported when GC/ECD was used to analyze headspace gases over water (Dietz and Singley 1979). Direct injection of water into a portable GC suitable for field use employed an ultraviolet detector (Motwani et al. 1986). While detection was comparable to the more common methods (low ppb), recovery was very low. Solid waste leachates from sanitary landfills have been analyzed for trichloroethylene and other volatile organic compounds (Schultz and Kjeldsen 1986). Detection limits for the procedure, which involves extraction with pentane followed by GC/MS analysis, are in the low-ppb and low-ppm ranges for concentrated and unconcentrated samples, respectively. Accuracy and precision data were not reported. 

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