Contamination sources 736 INDEX

One of the commonly used ventilation parameters is ventilation effectiveness, and it shows how certain regions in the room are influenced by contaminant sources introduced into the room. Three definitions of ventilation effectiveness are often used, namely, the ventilation effectiveness in the occupied zone the local ventilation index and the mean ventilation effectiveness They are defined as... 

An index is included at the end of the book which lists potential sources or origins for the contaminant of concern of interest. The index also includes compounds for which degradation products are known, e.g., the presence of 1,1-dichloroethane at a site may be indicative of a release containing 1,1,1-trichloroethane (where 1,1-dichloroethane is present as an impnrity) or it may be a degradation product of 1,1,1-trichloroethane. Therefore, under the 1,1-dichloroethane entry, the reader is directed to the chemical profile 1,1,1-trichloroethane. Moreover, the index inclndes compounds which occur as additives to various products, e.g., acrolein nsually contains hydroqninone to prevent polymerization. Many commercial prodncts released into the enviromnent may contain other compounds present as impurities, e.g., 1,4-dioxane may contain the impurities acetic acid, 2-methyl-1,3-dioxolane, and bis(2-chloroethyl) ether. 

Very often baseline problems are related to detector problems. Many detectors are available for HPLC systems. The most common are fixed and variable wavelength ultraviolet spectrophotometers, refractive index, and conductivity detectors. Electrochemical and fluorescence detectors are less frequently used, as they are more selective. Detector problems fall into two categories electrical and mechanical/optical. The instrument manufacturer should correct electrical problems. Mechanical or optical problems can usually be traced to the flow cell however, improvements in detector cell technology have made them more durable and easier to use. Detector-related problems include leaks, air bubbles, and cell contamination. These usually produce spikes or baseline noise on the chromatograms or decreased sensitivity. Some cells, especially those used in refractive index detectors, are sensitive to flow and pressure variations. Flow rates or backpressures that exceed the manufacturer s recommendation will break the cell window. Old or defective source lamps, as well as incorrect detector rise time, gain, or attenuation settings will reduce sensitivity and peak height. Faulty or reversed cable connections can also be the source of problems. 

Contaminated Fish Consumption. Serum cholesterol, serum GGT, and blood pressure, but not serum HDL cholesterol or triglycerides, were positively correlated with serum PCB levels in 458 residents of Triana, Alabama (Kreiss et al. 1981). These associations were independent of age, sex, fish consumption, body mass index, and alcohol consumption. Consumption of contaminated fish was the only known source of PCB exposure, but PCB intake was not estimated. DDT was also increased in the serum of the people and in the fish, and serum DDT and serum PCB levels were highly correlated. 

The determination of carbon and nitrogen utilization profiles can be performed in broth or pour plates seeded with the microorganism of interest. Success using these techniques require that fungi be in pure culture and that carbon and nitrogen sources be free of contamination. To interpret the broth method (Anonymous, 1984), a finely ruled white index card is placed behind the tube and the degree to which haze/turbid-ity hampers visualization is noted. Relative growth may be scored as follows ... 

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