Improving active biomonitoring in aquatic environments: The optimal number and position of moss bags

Abstract

The present study was carried out to determine the optimal number of moss bags of Fontinalis antipyretica required for biomonitoring stream water pollutants. With this aim, we examined the variability in the concentrations of Al, Cd, Co, Cu, Fe, Ni, Pb and Zn in 50 moss bags exposed in 4 different stream sampling sites (SS). In general, there were no significant differences in the element concentrations between groups of moss bags (n = 5), either along the 50 m length of each stream, or between the different sides of the streams. Considering errors of 10, 15 and 20%, the maximum number of moss bags required to estimate the mean tissue concentrations of the elements at the SS was respectively 26, 11 and 6. For most of the pairs of SS and elements studied, 5 or fewer moss bags were sufficient to differentiate between the mean concentrations. These findings allow us to conclude that a greater number of moss bags (at least 6) than those generally used until present should be utilized for biomonitoring water pollution with aquatic bryophytes.