Dioxinlike properties of a trichloroethylene combustion-generated aerosol.

Abstract

Conventional chemical analyses of incineration by-products identify compounds of known toxicity but often fail to indicate the presence of other chemicals that may pose health risks. In a previous report, extracts from soot aerosols formed during incomplete combustion of trichloroethylene (TCE) and pyrolysis of plastics exhibited a dioxinlike response when subjected to a keratinocyte assay. To verify this dioxinlike effect, the complete extract, its polar and nonpolar fractions, some containing primarily halogenated aromatic hydrocarbons, were evaluated for toxicity using an embryo assay, for antiestrogenicity using primary liver cell cultures, and for the ability to transform the aryl hydrocarbon receptor into its DNA binding form using liver cytosol in a gel retardation assay. Each of these assays detect dioxinlike effects. Medaka (Oryzias latipes) embryos and primary liver cell cultures of rainbow trout (Oncorhynchus mykiss) were exposed to concentrations of extract ranging from 0.05 to 45 micrograms/l. Cardiotoxicity with pericardial, yolk sac, and adjacent peritoneal edema occurred after exposure of embryos to concentrations of 7 micrograms/l or greater. These same exposure levels were associated with abnormal embryo development and, at the higher concentrations, death. Some of the fractions were toxic but none was as toxic as the whole extract. In liver cells, total cellular protein and cellular lactate dehydrogenase activity were not altered by in vitro exposure to whole extract (0.05-25 micrograms/l). However, induction of cytochrome P4501A1 protein and ethoxyresorufin O-deethylase activity occurred. In the presence of whole extract, estradiol-dependent vitellogenin synthesis was reduced. Of the fractions, only fraction 1 (nonpolar) showed a similar trend, although vitellogenin synthesis inhibition was not significant. The soot extract and fractions bound to the Ah receptor and showed a significantly positive result in the gel retardation/DNA binding test. Chemical analyses using GC-MS with detection limits for 2,3,7,8-tetrachlorodibenzo-p-dioxin and dibenzofuran in the picomole range did not show presence of these compounds. Our results indicate that other chemicals associated with TCE combustion and not originally targeted for analysis may also pose health risks through dioxinlike mechanisms.ImagesFigure 1.Figure 2.Figure 3. AFigure 3. BFigure 4. AFigure 4. BFigure 4. CFigure 4. DFigure 5.Figure 6.Figure 7.

Early life‐stage mortalities of Japanese medaka (Oryzias latipes) exposed to polychlorinated diphenyl ethers

“…Cardiac edema is commonly observed in embryos of medaka that have been exposed to HAHs that bind readily with the AhR [25,26]. However, there is recent evidence that edema in medaka embryos occurs through a mechanism that is independent of Ah‐mediated toxicity [35]. Exposure of salmonid embryos, including lake trout, to HAHs results in both subcutaneous edema of the yolk sac and cardiac edema [5,6].…”

Toxic responses of medaka, D‐rR strain, to polychlorinatednaphthalene mixtures after embryonic exposure by in ovo nanoinjection: A partial life‐cycle assessment

“…The score for lethality was set to 0.5 units greater than a severe‐case scenario of abnormalities, such as microphthalmia, no swim bladder inflation, severe pericardial edema, and moderate spinal curvature (a score of 11). Mortality and embryonic characterization of sublethal end‐points was done as described in Villalobos et al [16]. The scoring system was based on modifications from Weis and Weis [27], Middaugh et al [28], and Sharp [29] and was used only for postinjection monitoring of embryonic/early larval development.…”

“…These include changes in gallbladder coloration, swim bladder inflation, and larval performance (loss of equilibrium, mobility, and weakness). For a glossary of terms used to describe lesions, see discussions in Sharp [29] and Villalobos et al [16].…”

“…Medaka ( Oryzias latipes ) are small teleost fishes that are frequently used as adults and/or ELS in aquatic toxicity studies [15,16] and were deemed suitable for the relatively new egg injection assay. Their early life and adult stages are well characterized [17,18], and quantitative consistency of reproduction can be achieved under special conditions of diet, temperature, and photoperiod [19,20].…”

Eggshell and egg yolk proteins in fish: hepatic proteins for the next generation: oogenetic, population, and evolutionary implications of endocrine disruption

“…For example, exposure of juvenile rainbow trout to different doses of E 2 and CYP1A-inducers showed both elevation and reduction of plasma Vtg levels, depending on relative ratios of the test compounds [151-153]. In a recent study, exposure of juvenile salmon to an estrogen mimic (NP) and a CYP1A-inducer with documented anti-estrogenic activity (3,3'4,4'-tetrachlorobiphenyl; PCB-77) resulted in the potentiation of NP-induced synthesis of Vtg and Zr-proteins [117].…”