Toxic effects of nine polycyclic aromatic compounds on Enchytraeus crypticus in artificial soil in relation to their properties

The aim of this study was to compare the toxic effects of selected two- and three-ringed PAHs (naphthalene, phenanthrene, and anthracene) and their N-heterocyclic analogs with one (quinoline, acridine, and phenanthridine) or two (quinoxaline, phenazine, and 1,10-phenanthroline) nitrogen atoms on the survival and reproduction of Enchytraeus crypticus in artificial soil. Toxicity of compounds was recalculated to soil pore-water concentrations using the data of chemical analyses of 0.01 M CaCl2 extracts of spiked soils. When toxicity was based on molar concentrations in pore water (μmol/L), it significantly increased with increasing Kow value. This relationship indicates nonpolar narcosis as the general toxicity mechanism of the tested compounds. In addition, significant correlation between the toxicity of PACs and their ionization potential has been identified by multidimensional QSAR models.