Half-life estimates of three polychlorodibenzofurans (PCDFs) were calculated using serial blood samples collected over a 15 to 19-year period. Blood fat PCDFs were modeled in eight individuals who were exposed to contaminated rice oil in Japan (Yusho, n = 5) and in Taiwan (Yucheng, n = 3). The elimination kinetics of PCDFs were concentration-dependent, with faster rates observed at higher concentrations and the apparent transition to slower rates occurring at about 1-3 ppb. Average half-lives of 1.1, 2.3, and 1.5 years above the transition concentration and 7.2, 5.7, and 3.5 years below it were estimated for 2,3,4,7,8-pentaCDF, 1,2,3,4,7,8-hexaCDF, and 1,2,3,4,6,7,8-heptaCDF, respectively. A positive linear correlation of half-life with age was observed for the combined group, with a rate of increase of 0.19, 0.12, and 0.05-year half-life per year of increase in age for penta-, hexa-, and hepta-CDF, respectively. The distinctly younger Yucheng patients exhibited far lower variability in half-lives and age-related trends that were quite consistent with the corresponding data on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for younger persons exposed in the Seveso incident. These age- and concentration-dependent half-lives for PCDFs may have important risk assessment implications for estimating body burdens. The current study provides limited additional evidence that PCDFs, like TCDD, are more rapidly eliminated in younger individuals.

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The radionuclide content and 222Rn emanation coefficients of selected construction materials were determined. The materials were analyzed for 226Ra, 228Ra and 40K by gamma-ray spectrometry. Mineral wool insulation, which is made from Tennessee phosphate slag, and commonly used insulation, which is made from blast furnace slag, had similar concentrations of these radionuclides. Concrete blocks made with phosphate slag had enhanced 226Ra and 228Ra contents when compared to ordinary concrete block. The mineral wool insulation materials which were examined had emanation coefficients that were a few (2-6) times 10(-3). All other materials had emanation coefficients that ranged from 6 X 10(-4) to 4 X 10(-2).

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in storm water collected from 15 outfalls in San Francisco Bay, California, considered representative of areas located adjacent to petroleum refineries and mixed urban/commercial/residential land uses. Storm water sampling was conducted hourly over a 12-h period at two outfalls located near the city of Oakland and the suburban community of Benicia, which represent urban and mixed urban/light industrial land uses, respectively. Sampling was conducted hourly to determine temporal changes in the concentrations and distributions of PCDD/Fs during the first major rainstorm event of the 1995/96 winter season. In addition, storm water sampling was conducted in December 1995 and February/April 1996 at six publicly owned treatment work (POTW) outfalls located adjacent to developed, undeveloped, mixed residential/commercial, and industrial lands. Storm water sampling also was conducted at five outfalls located adjacent to petroleum refineries. The sampling results were used to examine changes in PCDD/F loadings to San Francisco Bay at the onset and midway through the winter rainy season and to characterize differences in PCDD/F concentrations, if any, between refinery and nonrefinery areas. The concentrations of tetra- through octa-chlorinated homologues and 2,3,7,8-substituted congeners were assayed in filtered storm water samples according to US EPA Method 1613A. Principal components analysis (PCA) was used as an exploratory technique to examine the similarities and differences in the distributions of PCDD/Fs in storm water from different outfalls. The sampling results showed few significant differences between storm water discharged from outfalls located in mixed urban/commercial/residential areas and outfalls located adjacent to petroleum refineries. The concentrations of 2,3,7,8-TCDD were below the analytical limits of detection in all storm water samples, with the exception of samples collected after the sixth hour of sampling at the Oakland outfall. Fingerprint patterns were generally dominated by the higher chlorinated PCDD/F congeners including OCDD, OCDF, and 1,2,3,4,6,7,8-HpCDD. Total TEQs were generally below US EPA ambient water quality criteria and aquatic ecotoxicology guideline values. The results of this study strongly suggest that discrete sampling of storm water outfalls is insufficient to characterize the concentrations and distributions of persistent hydrophobic contaminants such as PCDD/Fs. In addition to surface water runoff from the city of Oakland, other nonindustrialized urban locations may represent important sources of PCDD/Fs to San Francisco Bay.http://link.springer-ny.com/link/service/journals/00244/bibs/37n3p290.html