Conflicting outcomes of an integrated approach to sediment quality assessment in a Sardinian coastal area subjected to mining activities

Environmental Status of Italian Coastal Marine Areas Affected by Long History of Contamination

“…In geochemically anomalous areas, where high metal and trace element concentrations can be naturally enriched in the sediments, it was considered necessary to discriminate the geogenic contribution from the anthropogenic one (Xu et al, 2014;Romano et al, 2015Romano et al, , 2018aGuo and Yang, 2016;Birch, 2017, among the most recent ones). For this purpose, some sediment cores, sampled at high resolution (2 cm levels) and representative of the whole site, were used for reconstructing the evolution of contamination and determining the local background values (BGVs) (Matschullat et al, 2000;Apitz et al, 2009;Romano et al, 2015Romano et al, , 2018a.…”

“…In spite of this, bioassays (V. fischeri, D. tertiolecta, Brachionus plicatilis) carried out on both solid and elutriate did not highlight toxic response. These apparently conflicting outcomes were attributed to the fact that biogeochemical features of sea bottom and its aquatic/biotic interface constitute a dynamic and complex system, including an ensemble of variables, which in some cases, make it difficult to obtain univocal response by different lines of evidence (Romano et al, 2019b).…”

Sediment as a dynamic natural resource—from catchment to open sea

“…It highlighted: the need of a characterization survey for a better assessment of the pollution level; the importance of monitoring the long-term effects after remediation operations; and suggests a common Nordic database of clean-up remediation projects to improve the exchange of knowledge between the Nordic countries and the international community, and to harmonise guidelines for contaminated sediment handling. Romano et al (2020) compared chemical data and ecotoxicological responses to sediments that had been heavily contaminated by long-lasting mining activities with the aim to identify a reliable approach for the characterisation of sediment quality. Despite sequential extractions indicating the mobility of heavy metals, the marine biotests applied did not give positive responses.…”

Coastal Marine Geochemical Provinces and Background Values in Sediments: A Methodological Approach

“…Due to this geological setting (Figure 1), several structural units and magmatic provinces, with different chemism, outcrop in the mainland, representing the main sources for sediments, enriching them for one or more elements and determining geochemical anomalies (De Vivo et al, 2008). For example, Hg enrichments affect the sediments of the northern Adriatic and central Tyrrhenian seas, while Cr and Ni are enriched in the northern Tyrrhenian and Ligurian Seas sediments; As enrichments characterize sediments of specific sectors of the central and southern Tyrrhenian Sea, while Cd, Zn, and Pb enrich the sediments of the southern Sardinian Sea (Barghigiani et al, 1996;Bertolotto et al, 2005;Covelli et al, 2006;Piazzolla et al, 2015;Lopes-Rocha et al, 2017;Giglioli et al, 2020;Romano et al, 2020;Sarti et al, 2020 among others). Considering these aspects, the Italian law transposing the European directive introduced the option of identifying the marine geochemical provinces (MGPs) and establishing in each one "local" BGVs that replace the ones identified by the national decrees.…”