Soil screening for identifying ecological risk stressors using a battery of in vitro cell bioassays

Soil screening could be a process of identifying and defining areas, contaminants, and condition at the sites that warrant further attention for developing ecological risk assessments. In present work, a total of 41 surface soil samples from Tianjin, China were sampled and the soil organic extracts were evaluated using a battery of in vitro cell bioassays. The battery included ethoxyresorfin O-deethylase (EROD) with H4IIE rat hepatoma cells bioassay for Aryl hydrocarbon (Ah) receptor (Ah-agonists) effects, the SOS/umu bioassay for genotoxic effects, and human estrogen receptor recombinant yeast bioassay for estrogenic effects. The results have showed that total estrogenic effects in these soil samples was measured to be between 0.1 and 14.2 ng EEQ kg−1 soil (d.w.); Ah-agonists effects assayed by EROD bioassay varied from 2.8 ng TEQ kg−1 soil (d.w.) to 42.6 ng TEQ kg−1 soil (d.w.), and the amounts of soil weight required for the extracts to lead positive result (IR 2.0) in the SOS/umu bioassay were between 3.9 and 31.3 mg (d.w.) per well. In addition, the geographic distributions of Ah-agonists effects and genotoxic effects in Tianjin area exhibited a strong positive correlation with each other. However, the distribution of estrogenic effects with high levels in northwest Tianjin was markedly different from that of Ah-agonists effects, where the high levels were distributed in the urban of Tianjin, as well as coastal towns. It has been concluded that the toxicity assessment of surface soil using a battery of in vitro cell bioassays could provided meaningful information regarding characterization procedure in ecological risk assessment.