This study was designed to investigate the in vivo effects of benzo[a]pyrene (BaP) on hepatic ethoxyresorufin-O-deethylase (EROD) activity and its correlation with cytochrome P450 1A (CYP1A) protein levels in Sebastiscus marmoratus, which were exposed through a water column to BaP (10, 100, 1000 ng/L, respectively) or were treated with intraperitoneal injections of BaP (0.5, 1, 5, 10 mg/kg, respectively) every 7 d. The results showed that after 25 d of waterborne exposure to 1000 ng/L BaP, fish hepatic CYP1A levels and EROD activity were significantly induced. In contrast, EROD activity was not altered 7 d after second ip injections, whereas, CYP1A protein levels were increased. Dose-dependent increase of biliary BaP metabolites demonstrated that the catalytic activity of CYP1A was induced by treatment with BaP. The lowest observable effect concentration with regard to biliary BaP metabolites (100 ng/L) was much lower than that with reference to EROD activity (1000 ng/L). The results suggest that biliary polycyclic aromatic hydrocarbon (PAH) metabolites were shown to better reflect the contamination gradients of PAHs than EROD activity. It appeared to be necessary to measure CYP1A protein levels to complement the EROD activity in relevant toxicological assessments. 相似文献
Over the years several types of biocide-free antifouling paints have entered the market. The prohibition of biocidal antifouling paints in special areas of some European countries such as Sweden, Denmark and Germany has favoured the introduction of these paints to the market.
Several types of biocide-free antifouling paints were subjected to bioassays and selected chemical analysis of leachate and incorporated substances. Both non-eroding coatings (silicones, fibre coats, epoxies, polyurethane, polyvinyl) and eroding coatings (SPCs, ablative) were tested to exclude the presence of active biocides and dangerous compounds. The paints were subjected to the luminescent bacteria test and the cypris larvae settlement assay, the latter delivering information on toxicity as well as on efficacy.
The following chemical analyses of selected compounds of dry-film were performed:
• leaching-rate of organotin compounds from silicones and of nonylphenol and bisphenol A from epoxy and vinyl based coatings,
• concentration and leaching rate of selected organic compounds in polyurethane,
• concentration of heavy metals in eroding coatings.
The results of the bioassays indicated that none of the coatings analysed contained leachable biocides. Nevertheless, some products contained or leached dangerous compounds. The analyses revealed leaching of nonylphenol (up to 74.7 ng/cm2/d after 48 h) and bisphenol A (up to 2.77 ng/cm2/d after 24 h) from epoxy resins used as substitutes for antifouling paints. The heavy metal, zinc, was measured in dry paint film in quantities up to 576 000 ppm in erodable coatings, not incorporated as a biocide but to control the rate of erosion. Values for TBT in silicone elutriates were mostly below the detection limit of 0.005 mg/kg. Values for DBT ranged between <0.005 and 6.28 mg/kg, deriving from catalysts used as curing agents. Some biocide-free paints contained leachable, toxic and dangerous compounds in the dry film, some of which may act as substitutes for biocides or are incorporated as plasticizers or catalysts. Implications to environmental requirements and legislation are discussed. 相似文献
Previous research has shown that designers' and architects' evaluations of visual stimuli, and of urban and rural environments are not necessarily shared by non-designers and non-architects. Such conclusions may be biased by instrumentation and methodological problems, namely, previous instruments often require verbal responses about stimuli. Hence, non-designers and non-architects may be less capable in expressing themselves, but perceive the same things as the professionals. Another problem stems from professionals who have a narrow range of traits being compared with a general population that has a broader range of traits and therefore has greater within-group variance. This study presents an instrument and a methodology for dealing with these problems in addition to examining the perceptual orientations of architects in comparison to three other professions. Results indicate that architects varied from the other professional groups in their quantitative judgments of the habitats studied but not from all groups in their qualitative judgments. Hence, architects may be a distinct professional culture for some design variables only. 相似文献
Nanoporous carbons(NPCs) derived from metal–organic frameworks(MOFs) are attracting increasing attention in many areas by virtue of their high specific surface area, large pore volume and unique porosity. The present work reports the preparation of an NPC with high surface area(1731 m~2/g) and pore volume(1.68 cm~3/g) by direct carbonization of MOF-5. We examined the adsorption of three typical contaminants from aqueous solutions, i.e., sulfamethoxazole(SMX),bisphenol A(BPA) and methyl orange(MO), by using the as-prepared NPC. The results demonstrated that NPC could adsorb the contaminants effectively, with adsorption capacity(qm) of 625 mg/g(SMX), 757 mg/g(BPA) and 872 mg/g(MO), respectively. These values were approximately 1.0-3.2 times higher than those obtained for single-walled carbon nanotubes(SWCNTs) and commercial powder active carbon(PAC) under the same conditions. With its high surface area and unique meso/macropore structure, the enhanced adsorption of NPC most likely originates from the cooperative interaction of a pore-filling mechanism, electrostatic interaction,and hydrogen bonding. In particular, the p H value has a crucial impact on adsorption, suggesting the significant contribution of electrostatic interaction between NPC and the contaminants. This study provides a proof-of-concept demonstration of MOF-derived nanoporous carbons as effective adsorbents of contaminants for water treatment. 相似文献
Some environmental contaminants have the potential to affect humans or animals by mimicking the effects of hormones. Bisphenol A (BPA) is a weak estrogen agonist when tested using in vitro or in vivo bioassays. In addition to the well documented effects of estrogens on reproductive functions, ovarian hormones also have salient effects on mammalian energy balance and feeding behavior. In this study, we investigated the effects of BPA on body weight and food intake of ovariectomized adult female rats. Treatment with doses of 4 or 5 mg/day for 15 days resulted in a significant reduction of body weight gain with no reduction in food intake. A dose of 1 mg/day did not affect feeding or weight gain. BPA was detected in the blood, brain and adipose tissues of the BPA-treated animals but not in the vehicle control group. There was a preferential concentration of BPA in brown adipose tissue. These results indicate that BPA can affect energy balance and that brown adipose tissue may be a primary tissue into which BPA accumulates in mammals. 相似文献