1 research outputs found
Development and Application of a Novel Bioassay System for Dioxin Determination and Aryl Hydrocarbon Receptor Activation Evaluation in Ambient-Air Samples
Airborne
persistent toxic substances are associated with health
impacts resulting from air pollution, for example, dioxins, dioxin-like
polychlorinated biphenyls, and certain polycyclic aromatic hydrocarbons
(PAHs), which activate aryl hydrocarbon receptors (AhR) and thereby
produce adverse outcomes. Thus, a bioassay for evaluating AhR activation
is required for risk assessment of ambient-air samples, and for this
purpose, we developed a new and sensitive recombinant mouse hepatoma
cell line, CBG2.8D, in which a novel luciferase-reporter plasmid containing
two copies of a newly designed dioxin-responsive domain and a minimal
promoter derived from a native gene were integrated. The minimal detection
limit for 2,3,7,8-tetrachlorodibenzo-<i>p</i>-dioxin with
this assay system was 0.1 pM. We used CBG2.8D to determine dioxin
levels in 45 ambient-air samples collected in Beijing. The measured
bioanalytical equivalent (BEQ) values were closely correlated with
the toxic equivalent values obtained from chemical analysis. In haze
ambient-air samples, the total activation of aryl hydrocarbon receptors
(TAA) was considerably higher than the BEQ of dioxin-rich fractions,
according to the results of the cell-based bioassay. Notably, the
haze samples contained abundant amounts of PAHs, whose relative toxicity
equivalent was correlated with the TAA; this finding suggests that
PAHs critically contribute to the AhR-related biological impacts of
haze ambient-air samples