Talitrus saltator as a biomonitor: An assessment of trace element contamination on an urban coastline gradient

A novel approach to assess temporal baseline levels of trace metal contamination in the mussel M. galloprovincialis in the Mediterranean, Marmara and Black Seas

This study reports, for the first time, the baseline levels for fifteen trace metals in M. galloprovincialis tissue from around the Mediterranean, Marmara and Black Seas. The environmental quality in the surrounding seawater was assessed i.e., a mussel farm was investigated by using CF and DC indices, and the water quality was qualified as good for the aquacultural activities. A strong Cu-regulation in the transplanted mussels was observed and it ranged between 3.20 and 3.60 μg/g d.w. The highest bioavailability and bioconcentration of the particulate Fe fraction could present a health risk to consumers with a low risk level (1 < THQ < 9.9). Cr is considered the limiting metal for mussel consumption (< 2 kg/day). The metal contamination gradient was assessed using TEPI and TESVI indices that identified seven reference stations on the large scale and revealed that Cd is the most investigated metal in the literature databases, and found that Pb was the most bioavailable contaminant in the areas examined.

A first study on the bioaccumulation of trace metals in Rhyssoplax olivacea (Mediterranean Polyplacophora)

This study investigates, for the first time, the bioaccumulation of trace metals in the chiton Rhyssoplax olivacea. Fe, Cu, Co, Cr and Cd were measured in the shell and soft tissue of R. olivacea sampled in five sites along the Algerian west coast during the cold and hot seasons. Physiological and contamination indices were calculated. The condition index provides information on habitat quality and on R. olivacea reproductive performance and physiological status. The metal/shell-weight index informs on the bioavailability of trace metals. The trace element pollution index is used to assign a global contamination status to the studied sites. The trace element spatial variation index ranks Cd and Cr as trace metals of primary environmental concern based on the overall variability of their levels. An exhaustive review compiling data on trace element bioaccumulation in chitons is performed. The potential use of R. olivacea as bioindicator species is discussed.

Ecological and human health risk assessment of potentially toxic element contamination in waters of a former asbestos mine (Canari, Mediterranean Sea): implications for management

Between 1948 and 1965, the Canari asbestos mine (Corsica, France) discharged 11 million tonnes of serpentinite rubble into the sea. This study, therefore, aims to assess the environmental and health risks associated with contamination of potentially toxic elements using bioindicators (seagrass and fish) in the areas bordering the former mine within the perimeter of the Cap Corse and Agriate Marine Natural Park. The results and multivariate statistical analyses of the potentially toxic elements, made it possible to identify a concentration gradient, a model of bioaccumulation, and the occurrence of different groups, thus reflecting a spatial variation of the contamination. These results indicate that the former asbestos mine can still be considered, 55 years after its closure, as a major source of Co, Cr, and Ni for marine ecosystems and still influences the quality of the coastal area today. Our study, therefore, indicates that the two most polluted sites (Albo and Negru) are the closest stations to the south of the old Canary asbestos mine. According to the Trace Elements Pollution Index (TEPI) values, 6 species were classified as having a high contamination level: Scorpaena notata (1.37), Scorpaena porcus (1.36), Sepia officinalis (1.27), Diplodus vulgaris (1.02), Spicara maena (0.95), and Mullus surmuletus (0.94). Regarding the potentially toxic elements measured in the edible tissues of fish, the concentrations were all below the regulatory thresholds and did not reveal any potential risk to human health (Cd, Cu, Fe, Pb, Se, Sn, Zn). This work provides new and useful information to improve the monitoring of the environmental quality of a region characterized by previous mining activity and to assess the potential risk to human health due to the consumption of fish. Beyond the purely scientific aspects, these results could serve as decision support at the regional level for the definition of long-term public policies.

Walrus teeth as biomonitors of trace elements in Arctic marine ecosystems

Effective biomonitoring requires an understanding of the factors driving concentrations of the substances or compounds of interest in the tissues of studied organisms. Biomonitoring of trace elements, and heavy metals in particular, has been the focus of much research; however, the complex roles many trace elements play in animal and plant tissues can make it difficult to disentangle environmental signals from physiology. This study examined the concentrations of 15 trace elements in the teeth of 122 Pacific walruses (Odobenus rosmarus divergens) to investigate the potential for walrus teeth as biomonitors of trace elements in Arctic ecosystems. Elemental concentrations were measured across cementum growth layer groups (GLGs), thereby reconstructing a lifetime history of element concentrations for each walrus. The locations of GLGs were used to divide trace element time series into individual years, allowing each GLG to be associated with an animal age and a calendar year. The elements studied exhibited a great deal of complexity, reflecting the numerous factors responsible for generating tooth trace element concentrations. Generalized linear mixed models were used to investigate the importance of age and sex in explaining observed variation in trace element concentrations. Some elements exhibited clear physiological signals (particularly zinc, strontium, barium, and lead), and all elements except arsenic varied by age and/or sex. Pearson's correlations revealed that elements were more strongly correlated among calendar years than among individual walruses, and correlations of trace elements within individual walruses were generally inconsistent or weak. Plots of average elemental concentrations through time from 1945 to 2014 further supported the correlation analyses, with many elements exhibiting similar patterns across the ~70-year period. Together, these results indicate the importance of physiology in modulating tooth trace element concentrations in walrus tooth cementum, but suggest that many trace elements reflect a record of environmental exposure and dietary intake/uptake.

Gold(I) Complexes with a Quinazoline Carboxamide Alkynyl Ligand: Synthesis, Cytotoxicity, and Mechanistic Studies

A series of gold(I) complexes with the general formula [Au(L2)(L')] (L2=4-phenyl-N-(prop-2-yn-1-yl)quinazoline-2-carboxamide, L'=PPh3 (triphenylphosphine), 1; TPA (1,3,5-triaza-7-phosphaadamantane), 2, and Me2-imy (1,3-dimethylimidazol-2-ylidene), 3) were synthesized and fully characterized by spectroscopic methods. The alkynyl ligand L2 belongs to the quinazoline carboxamide class of ligands that are known to bind to the translocator protein (TSPO) at the outer mitochondrial membrane. 1 and 2 exert cytotoxic effects in bladder cancer cells with IC50 values in the low micromolar range. Further mechanistic analysis indicated that the two complexes both act by inducing reactive oxygen species and caspase-mediated apoptosis. The complexes inhibit thioredoxin reductase, an established target of anticancer gold(I) complexes. Docking studies confirmed that after ligand exchange the free ligand L2 can interact with the TSPO binding site.

Macroinvertebrates as biomonitors of pollutants on natural sandy beaches: Overview and meta-analysis

This review synthesises information from published articles on the incorporation of pollutants by macroinvertebrates from sandy beaches, including both field samplings and bioassays. The hypothesis that macroinvertebrates quantitatively reflect the presence of pollutants in sediment, acting as biomonitors, was tested through a meta-analysis based on studies performed in situ. More than half of the studies were conducted in the Mediterranean. Of the 53 articles based on field samplings, less than half (40%) determined the concentration of pollutants in the sediment as well as in the organisms. Donacidae, Talitridae, and Hippidae were tested as biomonitors, mainly of trace elements. Donacidae and Talitridae reflected in their soft tissues the presence of most trace elements in the sediment, which was not the case with Hippidae. Few studies (≤2 articles) evaluated the response of these macroinvertebrates to persistent organic pollutants, hydrocarbons, or microplastic. A selection based on sampling of sediment and species not yet tested as biomonitors is necessary due to the scarcity of a baseline worldwide and because responses to pollutants may be species-specific.

Spatio-temporal trace element fingerprinting of king scallops (Pecten maximus) reveals harvesting period and location

A rapidly growing human population is increasingly relying on seafood as a source of protein and other essential nutrients. Bivalve shellfish, both from wild populations and aquaculture, will undoubtedly continue to account for a significant portion of overall seafood production, but consumption of such shellfish carries potential health risks. Biotoxins, disease causing organisms and pollution contribute to this risk, as shellfish are indiscriminate, passive filter feeders. While government bodies, industry regulators and producers are capable of managing this risk, counterfeit produce can risk public safety, in turn damaging the reputation of the entire industry. Traceability tools provide a means to uphold food safety standards and mitigate remaining risk to consumers. Here, we show how the use of trace element (TE) signatures in shells and soft tissues of king scallops combined, can predict geographic origin with 100% accuracy. Importantly, we explore the temporal stability of this method, successfully classifying 100% of individuals correctly between two dates just 42 days apart from the same harvesting location. The most important elements in the trace element signatures of the scallops, discriminating between harvesting sites and dates were barium, boron, chromium, lead, manganese, molybdenum and selenium. The traceability tool described here offers a viable method to trace produce to its source, empowering industry regulators, government authorities, aquaculture practitioners and retailers in terms of tracking shellfish throughout the supply chain, which would comply with legislation and boost consumer confidence.

Trace element fingerprinting of blue mussel (Mytilus edulis) shells and soft tissues successfully reveals harvesting locations

Globally, aquaculture products are expected to account for >60% of total seafood produce by 2030. In the European Union, the seafood sector is of considerable economic importance to member states with household spending on seafood produce totalling €54.8 billion in 2016. Within the EU, shellfish aquaculture supports livelihoods and employment in many rural communities throughout the region. Harmful algal blooms pose considerable risk to consumer safety and in turn, stability of the shellfish market. If contaminated produce was to make it to the market the health risk to the public could be considerable, but the damage to the sector through loss of trust in producers would also be significant. Mytilus edulis account for a considerable portion of the aquaculture sector in the Northeast Atlantic. At present, no scientific tool is available to industry regulators, to allow them to trace mussel produce to its source, uphold food safety standards and ensure consumer confidence. The present study uses chemical analysis of shells and soft tissues to classify individual M. edulis to their site of harvest. The use of random forest classification of trace element composition has revealed location specific elemental signatures for all examined sites. This led to the correct classification of 100% of individuals sampled to their respective harvesting locations, including two sites located just 6 km apart within the same bay. The protocol demonstrated here provides the basis for a scientifically driven traceability framework for shellfish produce.

Microplastics in Talitrus saltator (Crustacea, Amphipoda): new evidence of ingestion from natural contexts

Using Fourier transform infrared spectroscopy (FT-IR) measurements and comparing the spectrum peaks (range 4000-600 cm^-1) with reference spectra database and instrument libraries, we observed new evidence of the ingestion of microplastic particles analyzing the digestive tracts of Talitrus saltator. Specimens, sampled in central Italy, probably ingested the particles with natural detritus. Since worldwide many species of invertebrates and vertebrates (e.g., birds) feed on Amphipoda along coastal ecosystems, we hypothesized that microplastic in these crustaceans can be accumulated along the food chain.

Quantification and feed to food transfer of total and inorganic arsenic from a commercial seaweed feed

Seaweed has a long-associated history of use as a supplemented livestock feed, providing nutrients and vitamins essential to maintaining animal health. Some species of seaweed, particularly the fucoids, are well-known accumulators of the metalloid arsenic (As). Arsenic toxicity to humans is well established even at low exposure levels and is considered a class 1 human carcinogen. As mankind's appetite for livestock produce continues to grow unabated, there is a concern that consumption of livestock produce reared on a diet supplemented with seaweed animal feed (SAF) may pose a threat to the human population due to potentially high levels of As present in seaweed. To address this concern and provide end users, including industry, consumers, policymakers and regulators with information on the exposure associated with As in commercial seaweed animal feed, the estimated daily intake (EDI) of As was calculated to evaluate potential human exposure levels. Using As data from a commercially available seaweed meal over a five-year period (2012-2017) a population exposure assessment was carried out. A Monte Carlo simulation model was developed to characterise the feed to food transfer of As from animal feed to animal produce such as beef, milk, chicken, and eggs. The model examined initial levels in seaweed, inclusion rate in animal feed, animal feeding rates and potential transfer to food produced from a supplemented diet of SAF. The analysis of seaweed animal feed showed that inorganic As was a small fraction of the total As found in seaweed meal (80:1). Statistical analysis found significant differences in the concentration of As in seaweed animal feed depending on the grain size (p < 0.001), with higher As concentrations in smaller sized grain fractions. Due to several detoxification steps and subsequent rapid excretion from the bodies of livestock, a very low carryover rate of As compounds from seaweed animal feed into livestock produce was observed. The EDI calculated in this study for the livestock produce evaluated at the 95th confidence interval was <0.01% of suggested safe levels of inorganic As intake. The threat to the general population as a result of consumption of livestock products reared on a diet consisting of SAF is found to be negligible.

Spatial variations in trace element concentrations of the sea urchin, Paracentrotus lividus, a first reference study in the Mediterranean Sea

A study on Trace Elements (TE) from sea urchin gonads has been conducted in the western Mediterranean Sea. Contamination data were used to determine a Trace Method Pollution Index (TEPI). TE concentrations varied considerably depending on the location of the sampling stations. The results showed that five trace elements (Zn, Fe, As, Al, Cu) are ubiquitous. The geographical area considered (Corsica) represents an important range of environmental conditions and types of pressure that can be found in the western Mediterranean Sea. TEPI was used to classify the studied sites according to their degree of contamination and allowed reliable comparison of TE contamination between local and international sites. TE contamination of the western Mediterranean Sea displayed a north-to-south gradient, from the Italian coasts down through the insular Corsican coasts to the north African littoral. Due to the increasing environmental pressure on the Mediterranean Sea, a regular monitoring of TE levels in marine organisms is necessary to prevent any further environmental deterioration.