Correlating ecotoxicological early-warning systems to biotic indices to assess riverine teratogenic contamination

We constructed a new ecotoxicological tool to test for the presence of teratogens in rivers by exploiting the regenerative capabilities of Hydra vulgaris because using living organisms is considered good practice in environmental monitoring for detecting detrimental pressures. Outputs on the Hydra assay were integrated with two biotic indices based on benthic invertebrates and macrophytes to evaluate whether the assay acts as a tool for detecting generalised freshwater conditions or as a biological test model revealing only the effects of dissolved teratogens. Several hypostomae of H. vulgaris were reared in waters collected in diverse southern central Latium rivers, where physiochemical descriptors were surveyed for environmental characterisation. The regeneration rate and amount of aberrations were evaluated to obtain a teratogenic risk index (TRI) score and then compared with the control. TRI calculations showed 4 sites (18.18%) in Class I (no risk), 15 sites (68.18%) in Class II (low risk), 2 sites (9.09%) in Class III (moderate risk) and 1 site (4.55%) in Class IV (high risk). No Class V sites (very high risk) were found. No significant correlations emerged among physicochemical parameters (except for PO43-), environmental descriptors, Simpson diversity indices and biotic indices and the TRI. These results promote an integrated approach to improving links between biological and ecological responses to anthropogenic impacts.