Polychlorinated biphenyl Laboratory studies

Alford Stevens et al. [49] carried out a multi-laboratory study of automated gas chromatography-mass spectrometric determinations of polychlorinated biphenyls in soil. The influence of various factors on the accuracy of analytical results were studied. Shaker extraction for 12.5h followed by Florisil chromatography were demonstrated to be the most reliable methods for extraction and clean-up. 

Alford Stevens et al. [49] have reported on an inter-laboratory study of the determination of polychlorinated biphenyls in environmental sediments. Electron capture gas chromatography and mass spectrometry were used to identify and determine polychlorinated biphenyls. For electron capture, an overall standard deviation of 30% was achieved while mass spectrometry gave 38%. 

A principal components multivariate statistical approach (SIMCA) was evaluated and applied to interpretation of isomer specific analysis of polychlorinated biphenyls (PCBs) using both a microcomputer and a main frame computer. Capillary column gas chromatography was employed for separation and detection of 69 individual PCB isomers. Computer programs were written in AMSII MUMPS to provide a laboratory data base for data manipulation. This data base greatly assisted the analysts in calculating isomer concentrations and data management. Applications of SIMCA for quality control, classification, and estimation of the composition of multi-Aroclor mixtures are described for characterization and study of complex environmental residues. 

Pattern recognition studies on complex data from capillary gas chromatographic analyses were conducted with a series of microcomputer programs based on principal components (SIMCA-3B). Principal components sample score plots provide a means to assess sample similarity. The behavior of analytes in samples can be evaluated from variable loading plots derived from principal components calculations. A complex data set was derived from isomer specific polychlorinated biphenyl (PCBS) analyses of samples from laboratory and field studies. 

The work described here was performed in a laboratory which had been specially modified and equipped to handle chemical carcinogens (10). Strict care was taken to avoid worker exposure to hazardous chemicals during the course of these studies. Reagent grade chemicals used for this work were 1,2-dichloroethane (Alfa Products, Danvers, MA) 1,1,1-trichloroethane (Matheson, Coleman Bell, Norwood, OH) 1,1,2-trichloroethane (J.T. Baker Chemical Co., Phillipsburg, NJ) n-heptane and n-hexane (Burdick Si Jackson Laboratories, Inc., Muskegon, MI). Also,used was a polychlorinated biphenyl whose chemical composition as determined... 

Abdul, A. S. Gibson, T. L. (1991). Laboratory studies of surfactant-enhanced washing of polychlorinated biphenyl from sandy material. Environmental Science Technology, 25(4), 665-71. 

In addition to the ability of TGA to quantify the thermal character of soil and sediment organic matter, it has been employed to study the adsorption of volatile organic compounds onto soil and sediment organic matter. For example, Boussehain et al. (1986) used TGA to study alcohol adsorption on charcoals, from which adsorp-tion/desorption isotherms were developed at various temperatures and adsorption models were used to lit experimental data. In addition, Risoul et al. (2002) performed laboratory pilot studies on thermal desorption of polychlorinated biphenyls (PCBs) from a contaminated soil. This study indicated that TGA appears to be a promising tool to determine optimum operating thermal extraction conditions. 

The saga of brominated flame retardants offers a cautionary tale for the chemical industry.65 These chemicals, developed in the early 1970s, are used in a wide range of consumer products, such as furniture, foam, and plastic casings of electronic devices. In 1998, Swedish scientists reviewing archived human breast milk samples discovered that certain flame retardant chemicals (polybrominated diphenyl ethers, or PBDEs) had doubled in concentration in Swedish breast milk about every five years over the preceding twenty. This was a source of concern, as studies of laboratory animals had shown that PBDEs dismpt thyroid hormones. Such dismption yields neurobehavioral effects similar to those of PCBs (polychlorinated biphenyls), whose manufacture the United States banned in 1976. 

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