Novel Quantitative Assessment for the Toxic Effect of Polycyclic Aromatic Hydrocarbon-Like Compounds in a Water Environment Using the Ethoxyresorufin O-Deethylase Microbioassay.

Abstract

The response of environmental pollutants can be detected bioanalytically focusing on the source and matrices of concern. Cell culture bioassays are rapid and inexpensive and thus have great potential for routine monitoring of aquatic resources. Such novel in vitro assays are a new tool to investigate lipophilic and low volatile compounds and are a powerful complement to instrumental analysis. The ethoxyresorufin O-deethylase (EROD) microbioassay was conducted to determine cytochrome P4501A (CYP1A) activity in environmental samples, and the calculated 3-methylchloranthrene (3-MC) equivalent concentration (MEQ) was introduced as a new quantitative water quality parameter. The chemical MEQ was calculated by multiplying induction equivalency factor (IEF) to GC-MS analysis data. And biological (bio-) MEQ was calculated by comparing the concentration response curve of the sample with those of the 3-MC calibration curve. Therefore, chemical MEQ is an estimation of the toxic effects of polycyclic aromatic hydrocarbons (PAHs) and bio-MEQ is the total toxic effects of various CYP1A-inducing chemicals in water samples. In this study, bio-MEQ values of water samples were higher than chemical MEQ values and total PAH concentrations, indicating that there must be other compounds in the water sample effective as inducers of EROD and that the biological activities of mixture compounds are mainly due to additive effects. There was a good correlation between bio-MEQ and total PAH concentration. The difference between bio-MEQ and total PAH concentration was high in downstream areas, i.e., polluted sites. Bio-MEQ calculated based on the enzyme-inducing effect of water samples could give information about the biological potency of water samples caused by PAH-like compounds.