Hydra vulgaris assay as environmental assessment tool for ecotoxicology in freshwaters: a review

Abstract

Freshwaters are vulnerable ecosystems owing to several anthropogenic impacts, including chemical pollution. Among existing model organisms, the cnidarian Hydra vulgaris is widely used for toxicological tests, with the aim of detecting either toxicity or teratogenicity of different dissolved chemicals. Given the widespread range of applications and developed assays, the aim of this review was to show and discuss the actual use of this model for ecotoxicological assessments in freshwaters as an ‘early warning system’. To achieve this goal, a thorough review was conducted by consulting several search engines for peer-reviewed international articles. Among all resulting articles from literature search, those focusing on H. vulgaris assay applied to environmental pollution were first selected (n=19). Then, only articles that specifically tested freshwater samples collected directly in the field were considered (n=4). The literature search highlighted that Hydra assays are suitable monitoring tools for freshwater ecotoxicity assessment. In addition, H. vulgaris allows testing diverse biomarkers (e.g. molecular, histological, morphological and behavioural) and exploring innovative research fields. So as to be able to assess the impact of emerging contaminants on both habitat and human health, the Hydra assays are demonstrating that they have an increasing potential that must be exploited.