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Previous studies suggested the suitability of the brackish-water serpulid (Ficopomatus enigmaticus) to be used as model organism for both marine and brackish waters monitoring, by the performance of sperm toxicity and larval development assays. The present study focused on larval development after the exposure of two F. enigmaticus populations (Mediterranean and Atlantic, collected in Italy and Portugal, respectively) to different trace elements (copper, mercury, arsenic, cadmium, and lead) at different concentrations. Results of larval development assays were presented as the percentage of abnormal developed larvae. The effect, measured in terms of EC 50 for all toxicants tested, showed that mercury was the most toxic metal for larvae of both populations. Specifically, the tested trace elements may be racked in the following order from the highest to the lowest toxicity: Mediterranean: mercury > copper > lead > arsenic > cadmium; Atlantic: mercury > copper > cadmium > arsenic > lead. Responses of both populations were similar for arsenic. Lead was the least toxic element for the Atlantic population, while cadmium showed the least toxicity for the Mediterranean population. These preliminary results demonstrate the sensitivity and suitability of the organisms to be used in ecotoxicological bioassays and monitoring protocols. Moreover, chemical analyses on soft tissues and calcareous tubes of collected test organisms and their sampling site water were performed, to identify and quantify the concentration of the tested trace elements in these 3 matrices. Populations exhibited less sensitivity to a certain element together with a relevantly higher concentration of the same element in soft tissues. This may indicate a certain resistance to particular contaminant toxic effects by organisms that tend to accumulate the same toxicant. This highlights the potential correlation between wild-caught test organisms' responses and a deep characterization of the sampling site to identify putative abnormalities or differences in model organism response during bioassay execution., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Ficopomatus enigmaticus is a serpulid polychaete, reef-forming, dioecious gamete spawner throughout different seasons and in different salinity conditions. Due to these characteristics, its candidacy as a model organism to monitor both marine and brackish matrices was assessed. Marine sediments collected in a polluted area near the port of Ancona (Italy) were used as case study. Besides the chemical characterization of sediments, the larval development of F. enigmaticus was adopted as an assay for ecotoxicological assessment of sediments in addition to a regulatory bioassay battery with different organisms and endpoints. The quality of sediments was classified according to the Italian Ministerial Decree for sediment management (Ministerial Decree 173, 2016) by using the SEDI-QUAL-SOFT® (ver. 109.0) software developed by the Italian Environmental Protection Agency (ISPRA). The F. enigmaticus larval development assay showed a quite similar sensitivity to C. gigas larval development assays, indicating its potential use in a regulatory battery of bioassays., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

In the present work we aimed to standardise the alkaline comet assay with erythrocytes of the cyprinodont, Mediterranean Killifish, Aphanius fasciatus. The aims of the study were to explore the suitability of this fish to assess biomarkers of genotoxic effects and as a sentinel organism to detect complex genotoxic mixtures in coastal lagoon ecosystems. Following proper optimisation, the application and effectiveness of the comet assay in erythrocytes of A. fasciatus were tested by measuring the tail DNA (%) induced by (a) in vivo exposure of individual fish to X-rays (dose, 3Gy) and (b) following in vitro challenge of erythrocytes with restriction endonucleases Fok-I and Eco-RI, which selectively induce double-strand breaks with cohesive and blunt termini, respectively. Furthermore, in order to evaluate whether circulating fish blood contained actively proliferating cells that could influence the extent of DNA damage in control (untreated) fish, we measured the number of "comets" positive for 5-bromo-2'-deoxyuridine (BrdU) by the use of anti-BrdU antibody and immuno-histochemical methods. Both treatments (i.e. with X-rays and restriction endonucleases) induced statistically significant increases in tail DNA (%) values compared with the relevant untreated controls, indicating the effectiveness of the comet assay in the erythrocytes of A. fasciatus to detect different types of DNA lesions. Results from anti-BrdU antibody labelling of erythrocytes indicated a very low percentage (5%) of "comets" positive for BrdU. Following optimisation and validation of the assay under laboratory conditions, fish were collected in the Orbetello lagoon (Tuscany, Italy), considered to be a significantly polluted site. The results showed statistically significant increases for tail DNA (%) compared with corresponding values observed in erythrocytes of fish caught in the unpolluted reference site "Saline di Tarquinia". The effects of physico-chemical parameters of the water (i.e., salinity, pH and oxygen content) did not significantly influence the induction of DNA damage. These results indicate that the comet assay provides a reliable parameter and that A. fasciatus is a promising "sentinel organism" to detect the genotoxic impact of complex mixtures in coastal lagoon ecosystems., (Copyright © 2011 Elsevier B.V. All rights reserved.)