In Situ Investigation of Trace Metal Availability in Industrial Effluents Using Transplanted Aquatic Mosses

Three species of aquatic mosses, Rhynchostegium riparioides, Fontinalis antipyretica, and Cinclidotus danubicus, were collected from the same reference location and exposed in five industrial effluents. The purpose was to test their suitability for assessing trace metal contamination under adverse and contrasted environmental conditions. Two distinct experiments of 16 and 11 days were conducted. In spite of short residence times in the effluents, the bryophytes were considerably affected at several sites, showing a light green to yellowish color, brown-edged leaves, and even dead strands. Cinclidotus danubicus was the most resistant whereas Fontinalis antipyretica was the most sensitive species. The observed physiological damage had no obvious incidence on the accumulation capacity of the mosses. The biomonitors provided time-integrated patterns of trace metal bioavailability (copper, chromium, nickel, lead, and zinc) in the effluents with a clear discrimination between poorly, moderately, and heavily polluted sites. Compared to water analyses, these more reliable indications could be obtained with a considerably reduced sampling design. When substantial accumulation occurred in mosses, the highest concentrations were systematically found in Rhynchostegium riparioides and the lowest in Cinclidotus danubicus. As only quantitative, not qualitative, differences were observed, all investigated moss species can be recommended for the assessment of trace metals in effluents at their discharge into the natural environment.