E. De Felip

An overview of TCDD half-life in mammals and its correlation to body weight.

Major determinants of TCDD half-life in organisms are lipophilicity, metabolism, and hepatic binding sites. In addition, half-life seems to be empirically correlated to organism body weight. In this paper, this correlation is evaluated by a regression analysis of half-life measures and body weight data selected from the literature. Single exposure studies on laboratory mammals and human half-life data were specifically taken in consideration. The analysis outcome appears to be highly significant probably owing to the stability and generally slow metabolism of the substance in the organisms considered. The effect on half-life of factors other than body weight does not seem to influence significantly data dispersion around the regression line. The potential effects of a dose-dependent excretion cannot be excluded as toxicokinetic studies have been usually carried out at high exposure doses.

Mercury (Hg) and methyl mercury (MeHg) concentrations in fish from the coastal lagoon of Orbetello, central Italy

Total mercury (Hg tot) and methyl mercury (MeHg) were quantified in several specimens of Dicentrarchus labrax and Sparus aurata from the east basin of the Orbetello lagoon, central Italy. The size of each specimen was recorded to estimate body burdens (BBs); =Hg tot and MeHg were measured in fillets of both species. Hg tot and MeHg in S. aurata ranged between 0.355-1.58 and 0.341-1.53 μg/g wet weight (ww), respectively; in D. labrax, their ranges were 0.284-2.54 and 0.214-2.35 μg/g ww. Approximately 90% of the concentrations measured exceeded Hg tot regulatory maximum level of 0.5 μg/g ww; however, exceedance rate was different in the two species studied. No correlations between specimen size and Hg tot or MeHg BBs were detected in this study.

Structure-dependent photocatalytic degradation of polychlorobiphenyls in a TiO2 aqueous system

Abstract Three positional isomers for each polychlorobiphenyl (PCB) homologous group tetra-, penta-, and hexachlorosubsubstituted were irradiated in a TiO 2 (anatase) semiconductor aqueous suspension. Parent PCB disappearance was studied as a function of irradiation time, and a correlation between isomer substitution pattern and the photodegradative behavior was shown. In each group, the slowest disappearance trend was exhibited by the isomer with unsubstituted ortho positions, thereby capable of adapting into a planar structural configuration with minimum (estimated) energy requirement. In general, photodegradation rate increased with increasing degree of ortho chlorosubstitution.

Determination of the composition of complex chemical mixtures in the soil of an industrial site

Abstract Since the late 1800s, the ACNA chemical plant at Cengio (Savona, northern Italy) has used a large portion of the 55 ha of land that it owns to dispose of its chemical wastes and refuse materials by dumping and burying them in the earth. As a result of this practice, an extent of ground of well over 106 m3 and up to 20 m thick has become highly contaminated. In addition, due to the local hydrogeological conditions, for years the site has been a contamination source for the nearby Bormida River and the territory downstream. Since satisfactory primary knowledge of the quality and quantity of the soil contamination of the site was not available, a pilot study was financed to provide the information required. In this paper, the analytical approach to and procedure for the multianalyte multilaboratory assessment in complex soil and sediment matrices are described. The analyte group includes nine families of chemicals which exhibit highly variable toxic potentials, water solubilities, and kows (lg[kow] approximately between 2 and 12). A preliminary appraisal of the procedure is presented with specific reference to the detection of polychlorinated dibenzodioxins, dibenzofurans, and biphenyls of the first 43 subsoil and sediment samples from the site. Also, a comparison is made to the Seveso/ICMESA accident of July 1976.

Polychlorodibenzodioxin and polychlorodibenzofuran levels in dielectric fluids containing polychlorobiphenyls

Abstract Forty‐two dielectric fluids from long‐operated heavy‐duty electrical appliances still in service were assayed for polychlorobiphenyls (PCBs); findings ranged from 5 g/kg was also tested for polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs). Cumulatively, these chemicals were seen to fall in the range of 0.76–77 mg/kg of PCBs; and UCL (95%) were estimated as 7.8 and 20 mg/kg, respectively. PCB, PCDD, and PCDF levels were also measured in 17 heterogeneous matrices from accidents involving electrical equipment. With reference to the above background values, no increases in the PCB‐normalized cumulative PCDD and PCDF levels were detected in connection with explosion‐type accidents, whereas matrices from electrical facilities affected by a fire exhibited PCDD and PCDF level increases which were up to four orders of magnitude (140 g/kg of PCBs, in one case). A set of six wipe specimens from the same accident site yield...

Fast Gas Chromatographic Assessment of Polychlorobiphenyl Levels in Wall Plaster Coats

Abstract Sampling (“scrape test”) and analytical procedures were defined to determine PCBs in sorbing solid surfaces such as wall plaster. After sampling, samples were extracted by means of a mechanical device. Following steps included clean-up on a multilayer chromatographic column and assessment with macrobore capillary gas chromatography equipped with an electron capture detector. Mean recovery yields were ≧75% for PCB levels from 2.00 to 7000μg/m2 (0.550–1940 μg/kg). Intralaboratory tests performed by two independent operators yielded: (a) maximum deviation from expected value, 25%; (b) maximum deviation between operators, 17%; and (c) maximum variation coefficient, 20%. Background PCB levels in wall surface layer samples were ≧2.9μg/m2 (≧0.81 μg/kg). The analytical procedure tested with agricultural topsoil samples provided mean recovery yields >65% for PCB levels ≧500 μg/ kg (≧ 50 mg/m2).

Levels of 4-chloro-2-methylphenoxyacetic acid (MCPA) in the urine of northern Italy occupationally exposed agricultural workers

MCPA residues were assayed in 18 urine samples collected from northern Italy herbicide spraymen. Urine was collected within less than or equal to 24 hr from workshift start and kept at -20 degrees C until analysis. Twenty-five-milliliter urine specimens were ether-extracted at pH 1 and then the free MCPA was turned into its methyl ester. Detection and quantitation were carried out by high-resolution gas chromatography coupled with low-resolution mass spectrometry (hrGC-lrMS) run in the multiple ion detection (MID) mode. Specimen mass chromatograms were referred to MCPA methyl ester external standards. Detection thresholds were 25 and 10 ppb when S/N ratios of approximately 10 and 2.5, respectively, were adopted for the quantitation ion mass. Mean recovery was better than 80% over the full concentration range tested (10-1000 ppb). Urine analysis yielded the following results: eight outcomes fell in the 10-50 ppb range, five outcomes in the 50-150 ppb range, and five in the 150-500 ppb range.