Evaluating three trace metal contaminated sites: a field and laboratory investigation

Selecting guidelines to evaluate elevated metals in urban brownfields is hi ndered by the lack of information for these sites on ecosystem structure an d function. A study was performed to compare three trace metal-contaminated sites in the metropolitan Montreal area. The goal was to obtain an idea of the organisms that may be present on urban brownfields and to measure if e levated metals alter the presence and activity of the indigenous biota. Fie ld and laboratory studies were conducted using simple methodologies to dete rmine the extent to which microbial activity affected by trace metal conten t, to assess diversity of plant and soil invertebrate communities and to me asure phytoaccumulation of trace metals. It was found that microbial activi ty, as measured by substrate-induced respiration (SIR) and nitrification, w as not affected by the levels of soil Cd, Cu, Ni, Pb and Zn recorded on the sites. Seven of the 12 invertebrate groups collected were sampled on soils with similar Cd, Cu, Ni, Pb and Zn concentrations. Diversity of plant spec ies increased as a function of the length of time the sites had been inacti ve. Levels of metals in plant tissue were influenced by soil characteristic s and not by total soil Cd, Cu, Ni, Pb and Zn. (C) 1999 Elsevier Science Lt d. All rights reserved.