Reversibility of trace metals effects on sea urchin embryonic development

CTED
The sea urchin embryo-toxicity test is widely used to assess the toxicity of contaminants and environmental
matrices. In standard guideline and literature studies, the classical toxicity criteria are based on distinguishing
between normal and abnormal embryos at pluteus stage. The aim of this research was to further expand the po
tentiality of the recently developed Integrative Toxicity Index (ITI), investigating the reversibility of the effects
induced by various trace metals (cadmium, copper, lead and zinc) on sea urchin development. For this purpose,
embryos were observed after different periods of exposure and recovery to metals. Results were analysed com
paring ITI with standard criteria, thus moving from the simple observation of general effects to the classification
of their severity. The onset and reversibility of effects by trace metals were more efficiently discriminated by the
use of the ITI, which recognized and weighted the delay and degree of various abnormalities. Above, this study
was expected to provide new insights into the capability of each metal to induce anomalies leading to a block or
delay in embryogenesis of the embryos to recover normal development after metal exposure, thus adding further
ecological value to the sea urchin bioassay.