Vitamin and thyroid status in arctic grayling (Thymallus arcticus) exposed to doses of 3,3',4,4'-tetrachlorobiphenyl that induce the phase I enzyme system

Induction of phase I biotransformation enzymes is recognized as a hallmark response in fish exposed to coplanar PCBs. Depletions of vitamins A and E and disrupted thyroid hormone and glandular structure secondary to this induction have not yet been examined in an arctic fish species. Arctic grayling were exposed to a single oral dose of 0 (control), 10, 100 or 1000 ng 3,3',4,4'-tetrachlorobiphenyl (TCB) g(-1) bodyweight, a contaminant found in most arctic fish. After 30 and 90 days of exposure, TCB concentrations in tissues, hepatic phase I activity (as ethoxyresorufin-O-deethylase (EROD)), plasma and tissue vitamin A and E concentrations, plasma thyroid hormone levels and thyroid glandular structure were examined. Total plasma osmolality, as an indicator of overall fish health was also monitored. TCB recovery in tissues was low and extremely variable, making comparisons between intended dose groups inappropriate. Therefore, correlation analysis between actual recovered TCB concentrations and biochemical responses was employed. Hepatic EROD activity correlated strongly with liver TCB concentrations. Liver concentrations of vitamin A were altered as a function of TCB concentrations and EROD activity, but plasma vitamin A status was not affected. Vitamin E was depleted by TCB accumulation in blood and EROD induction in liver of males only at 90 days postexposure. Thyroid hormones status and glandular structure were not affected by the short duration TCB exposures used in this experiment. TCB concentrations were correlated with an elevation in plasma osmolality. Results from this experiment indicate that the vitamin status and osmoregulation of arctic grayling exposed to TCB can be compromised. Further studies of field populations exposed to this type of contaminant are warranted.     

Analysis of Ah receptor pathway activation by brominated flame retardants

Brominated flame-retardants (BFRs) are used as additives in plastics to decrease the rate of combustion of these materials, leading to greater consumer safety. As the use of plastics has increased, the production and use of flame-retardants has also grown. Many BFRs are persistent and have been detected in environmental samples, raising concerns about the biological/toxicological risk associated with their use. Most BFRs appear to be non-toxic, however there is still some concern that these compounds, or possible contaminants in BFRs mixtures could interact with cellular receptors. In this study we have examined the interaction of decabromodiphenyl ether, Firemaster BP4A (tetrabromobisphenol A), Firemaster PHT4 (tetrabromophthalic anhydride), hexabromobenzene, pentabromotoluene, decabromobiphenyl, Firemaster BP-6 (2,2^′,4,4^′,5,5^′-hexabromobiphenyl) and possible contaminants of BFR mixtures with the Ah receptor. Receptor binding and activation was examined using the Gel Retardation Assay and increased expression of dioxin responsive genes was detected using the reporter gene based CALUX assay. The results demonstrate the ability of BFRs to activate the AhR signal transduction pathway at moderate to high concentrations as assessed using both assays. AhR-dependent activation by BFRs may be due in part to contaminants present in commercial/technical mixtures. This was suggested by our comparative analysis of Firemaster BP-6 versus its primary component 2,2^′,4,4^′,5,5^′-hexabromobiphenyl. Some technical mixtures of brominated flame-retardants contain brominated biphenyls, dioxins or dibenzofurans as contaminants. When tested in the CALUX assay these compounds were found to be equivalent to, or more active than their chlorinated analogues. Relative effective potency values were determined from dose response curves for these brominated HAHs.     

Chlorinated hydrocarbons in Scots pine needles in northern Britain

Concentrations of 4 chlorinated hydrocarbons, C2H3Cl3 (1,1,1-trichloroethane), CCl4 (tetrachloromethane), C2HCl3 (trichloroethene) and C2Cl4 (tetrachloroethene) have been measured in needles of Scots pine (Pinus sylvestris L.) growing close to two industrial sites and in a rural area in northern Britain. Pentane extracts of pine needles sampled over 14 months were analysed using gas chromatography with electron capture detection. Geometric mean concentrations were not significantly different among the sites, with values (in ng g(-1) dry weight) of 7-15 for C2H3Cl3, 3.2-6.5 for CCl4, 70-240 for C2HCl3 and 11-26 for C2Cl4. There was no evidence of accumulation with needle age, but more exposed sites (e.g. those higher in the canopy) showed significantly larger concentrations. The influence of possible local sources could not be detected.     

Waste Streams,Technology, and State Requirements

Biomedical wastes are generated by hospitals, laboratories, animal research facilities, and by other institutional sources. The disposal of these wastes is coming under critical public scrutiny, and regulations are being promulgated to control their disposal. Incineration is not a final disposal method since it generates a solid residue (ash) which must be buried or otherwise disposed. The incineration process, however, renders the waste non-toxic, non-hazardous, and non-putrescible, and reduces the volume of material for ultimate disposal by an order of magnitude. In some instances, the residue may have high levels of heavy metals; however, this is the exception rather than the rule.     

The assessment of the possible inhibitory effect of dyestuffs on aerobic waste-water bacteria experience with a screening test

This paper describes the development of, and one year's experience with, a screening method based on the measurement of the respiration rate of activated sludge for assessing the possible inhibitory effect of dyestuffs on aerobic waste-water bacteria. Of the 202 dyestuffs tested, about 10% showed an inhibiting effect such that should significant quantities be likely to reach a sewage treatment plant a closer assessment of the likely effects would be indicated.     

The release of lindane from contaminated building materials

The release of the organochlorine pesticide lindane (γ-hexachlorocyclohexane) from several types of contaminated building materials was studied to assess inhalation hazard and decontamination requirements in response to accidental and/or intentional spills. The materials included glass, polypropylene carpet, latex-painted drywall, ceramic tiles, vinyl floor tiles, and gypsum ceiling tiles. For each surface concentration, an equilibrium concentration was determined in the vapour phase of the surrounding air. Vapor concentrations depended upon initial surface concentration, temperature, and type of building material. A time-weighted average (TWA) concentration in the air was used to quantify the health risk associated with the inhalation of lindane vapors. Transformation products of lindane, namely α-hexachlorocyclohexane and pentachlorocyclohexene, were detected in the vapour phase at both temperatures and for all of the test materials. Their formation was greater on glass and ceramic tiles, compared to other building materials. An empiric Sips isotherm model was employed to approximate experimental results and to estimate the release of lindane and its transformation products. This helped determine the extent of decontamination required to reduce the surface concentrations of lindane to the levels corresponding to vapor concentrations below TWA.