RESUMO
Computational chemistry, in conjunction with gas chromatography/mass spectrometry/Fourier transform infrared spectrometry (GC/MS/FT-IR), was used to tentatively identify seven tetrachlorobutadiene (TCBD) isomers detected in an environmental sample. Computation of the TCBD infrared spectra was performed with the Gaussian quantum chemistry software. The Hartree-Fock/6-31G* level of theory was employed, with IR frequencies scaled by a standard factor of 0.89. This approach shows great promise as a means of characterizing or confirming environmental analyte identifications when standard spectra, or pure standards required to measure standard spectra, are unavailable.
RESUMO
A field study was performed which compared predicted and measured concentrations of chemicals in receiving water organisms from three sampling locations on Five Mile Creek, Birmingham, Al. Two point source discharges, both from coke manufacturing facilities, were included in the field site and five chemicals were studied, i.e., biphenyl, phenanthrene, anthracene, fluoranthene, and pyrene. Composite samples of effluent, receiving water organisms, crayfish (Decapoda) and sunfish (Lepomis sp.), and stream and discharge flow data were collected in March and April 1990. For the crayfish and sunfish, the measured residues were within a factor of 5 for 80% (12 of 15) and 53% (8 of 15) of the residues predicted using EPA's draft procedure (US-EPA 199 lb), respectively, and were within a factor of 5 for 60% (9 of 15) and 40% (6 of 15) of the residues predicted using EPA's procedure with a BCF set equal to the chemical's Kow (after adjustment for lipid content of the organism), respectively. The predicted residues tended to be larger than the measured residues and with increasing Kow, greater disagreement between the predicted and measured values was observed.