The temporal and spatial variability in the chemical properties of freshwater ecosystems demand for novel approaches tackling the rapid changes induced by anthropogenic activities. The possible approaches can be divided into two classes: high resolution and integration strategies. The biomonitoring through accumulator organisms falls into the latter group and can be adopted in deriving time-integrated measures of environmental contamination and accurate spatial gradients. To accomplish these goals, the organisms should linearly accumulate pollutants in relation to the environmental concentrations, being able to live in the selected environments and be common, easily recognized and managed. In searching for better biomonitors matching thes...