Sea urchin embryotoxicity test: proposal for a simplified bioassay.

Sea urchin embryotoxicity tests are widely used for evaluating the biological effects of contaminants in marine environments. The currently used traditional and standardized protocols are quite slow and laborious. The present work shows a modified bioassay (new embryotoxicity test; NET) in an attempt to speed up laboratory work using a limited number of fertilized eggs. Several experiments have been conducted both with a traditional bioassay and with the NET, using the same test conditions, in order to evaluate the reliability of the proposed simplified bioassay. Adult Paracentrotus lividus (Lamark) were collected from the Tyrrenian Sea (Bay of Naples) and embryos, reared in filtered seawater, were exposed to increasing potassium dichromate and copper sulfate concentrations. Then the EC(50) was calculated. The analysis of the results evidenced good repeatability. The confidence limits in all tests overlapped; moreover, data correlation analysis between the results of both tests showed a high significant accordance (chromium, R2 = 0.93, P < 0.01; copper, R2 = 0.86, P < 0/05). In conclusion, the NET seems to be a good alternative to the traditional tests; it could be a first step toward a new routine ecotoxicological kit for seawater.