Applying Bioassay Methods for Ecological Assessment of the Soils from the Brownfield Sites

Biological organisms, used as test objects in pollution tests may be as good, or even more so, in detecting soil contamination, than chemical analyses. In this study, we used five bioassay methods, together chemical and physical-chemical tests, for comprehensive environmental assessment of contaminated soils located at the industrial waste storage sites in North-West Russia. Examined soils have been contaminated with various toxic pollutants at various times in the past. The level of contamination by Hg, Pb, Cd, Zn, Co, As, Cr, Cu, Mn, V, and As in studied soils varied depending on a site type. The concentrations of these elements were 20 to 43 times higher than the regional geochemical baseline at all sites. The organic pollutants (3,4-benzo(a)pyrene and polychlorinated biphenyls) were found at some sites. Ecotoxicological studies were carried out using test organisms from different taxonomic groups: ciliates Paramecium caudatum Ehrenberg, green algae Scenedesmus quadricauda (Turp.) Brebisson, seeds of common oat Avena sativa L., wheat Triticum aestivum L., and a natural community of microorganisms. All the employed bioassays revealed some of the aspects of contamination, supported or supplemented each other's estimates, and gave excellent performance at the sampling sites.