Assessment of environmental stress in Parablennius sanguinolentus (Pallas, 1814) of the Sicilian Ionian coast

Toxic metals in Loggerhead sea turtles (Caretta caretta) stranded freshly dead along Sicilian coasts

BACKGROUND

The Loggerhead sea turtle (Caretta caretta) is a marine reptile belonging to a monophyletic group of chelonians. As these animals are long-lived, they have the ability to accumulate pollutants.

AIM

To collect epidemiological data on toxic metals in marine Loggerhead sea turtles.

MATERIALS AND METHODS

Forty Loggerhead sea turtles comprising 25 males and 15 females stranded freshly dead between 2013 and 2018 along the coasts of Sicily, Southern Italy, were examined for arsenic, cadmium, and lead accumulation in muscle and adipose tissues by means of a validated ICP-MS method. A modified K index as a growth condition factor, namely Fulton's K index, was used. Samples were tested in duplicate. A Wilcoxon rank sum test was carried out to evaluate metal contents differences between muscle and adipose tissues and between genders.

RESULTS

The Fulton's K index suggested a good body condition of the C. caretta recovered with mean values of 5.34 ± 3.40 (n = 40; ±SD). Detectable concentrations of lead were found in 70% of the samples analysed with mean values of 0.65 ± 1.67 mg/kg wet weight and 0.51 ± 1.29 mg/kg wet weight in muscle and adipose tissues, respectively. No significant differences in arsenic, cadmium, and lead were detected between genders. In addition, no significant correlation was found between modified K index and concentrations of arsenic, cadmium, and lead.

CLINICAL RELEVANCE

Findings on muscle and adipose tissues suggest chronic exposure of Caretta caretta to high concentrations of especially lead which might negatively affect health and welfare of these marine turtles although body condition was good.

Trace elements in the muscle tissue of Hemiculter leucisculus and Abramis brama orientalis from the Anzali International wetland, south-west of Caspian Sea: An exposure risk assessment

High levels of trace elements in aquatic environments can affect the quality of seafood. We analyzed the concentrations of As, Cd, Co, Hg, Mn, Ni and Pb, in the edible muscles of Hemiculter leucisculus and A. brama orientalis caught in four different areas of southwest of the Caspian Sea. We estimated the potential risks for human health deriving by the oral consumption of these two species, and the Target Hazard Quotient (THQ) according to the US-EPA approach. THQ by adults and children was always below 1 for all stations. The greater contribution was given by Co, followed by Cd, Hg, Pb, Ni, As and Mn. Total-THQ was 0.538 and 0.246 for children and adults, respectively. Trace elements detected by our study were not elevated, highlighting a positive picture of the studied area and a lower risk of developing chronic systemic effects deriving from the consumption of local fish products.

Microplastic abundance and biodiversity richness overlap: Identification of sensitive areas in the Western Ionian Sea

Plastic pollution in the Mediterranean Sea has been widely reported, but its impact on biodiversity has not been fully explored. Simultaneous sampling of microplastics (MP) with a manta net and surveys of large marine vertebrates were conducted along the coastal waters of Sicily (Western Ionian Sea). A total of 17 neustonic samples have been collected and 17 marine species (cetaceans, sea turtles, seabirds, and fish) have been sighted in the target area. Kernel density estimation was evaluated to highlight a possible overlap between the presence of large marine fauna and MP densities to provide a preliminary risk assessment. The highest biodiversity and MP concentration (0.197 ± 0.130 items/m²) were observed in the southernmost part of the studied area. The overlap between biodiversity hotspots and the occurrence of MP, potential contribute to the identification of sensitive areas of exposure in a poorly studied region.

Chemical Characterization and Quantification of Silver Nanoparticles (Ag-NPs) and Dissolved Ag in Seafood by Single Particle ICP-MS: Assessment of Dietary Exposure

This study provides a first insight on the chemical characterization and quantification of silver nanoparticles (AgNPs) and dissolved Ag in processed canned seafood products, where food-grade edible silver (E174) is not intentionally added nor is the nanoparticle contained in the food contact material. The aim was to evaluate the bioaccumulation potential of AgNPs and to contribute to the assessment of AgNPs and ionic Ag human dietary intake from processed seafood. It is known how seafood, and in particular pelagic fish, is a precious nutritional source of unsaturated fatty acids, protein, and different micronutrients. Nevertheless, it may cause possible health problems due to the intake of toxic compounds coming from environmental pollution. Among emerging contaminants, AgNPs are widely applied in several fields such as biomedicine, pharmaceutical, food industry, health care, drug-gene delivery, environmental study, water treatments, and many others, although its primary application is in accordance with its antimicrobial property. As a consequence, AgNPs are discharged into the aquatic environment, where the colloidal stability of these NPs is altered by chemical and physical environmental parameters. Its toxicity was demonstrated in in-vitro and in-vivo studies, although some findings are controversial because toxicity depends by several factors such as size, concentration, chemical composition, surface charge, Ag⁺ ions released, and hydrophobicity. The new emerging technique called single-particle inductively coupled plasma mass spectrometry (spICP-MS) was applied, which allows the determination of nanoparticle number-based concentration and size distribution, as well as the dissolved element. Our findings highlighted comparable mean sizes across all species analysed, although AgNPs concentrations partly follow a trophic level-dependent trend. The low mean size detected could be of human health concern, since, smaller is the diameter higher is the toxicity. Dietary intake from a meal calculated for adults and children seems to be very low. Although seafood consumption represents only a small part of the human total diet, our findings represent a first important step to understand the AgNPs dietary exposure of the human population. Further studies are needed to characterize and quantify AgNPs in a large number of food items, both processing and not, and where AgNPs are added at the industrial level. They will provide a realistic exposure assessment, useful to understand if AgNPs toxicity levels observed in literature are close to those estimable through food consumption and implement data useful for risk assessors in developing AgNPs provisional tolerable daily intake.

Bioaccumulation of Metals/Metalloids and Histological and Immunohistochemical Changes in the Tissue of the European Hake, Merluccius merluccius (Linnaeus, 1758) (Pisces: Gadiformes: Merlucciidae), for Environmental Pollution Assessment

Pollution and other types of environmental stress do not spare marine environments, especially those affected by high industrial pressure. Fish, especially coastal species, are used for monitoring the marine environment because they are particularly efficient as bioindicators thanks to their ability to bioaccumulate and biomagnify along the trophic chain. The aim of this research is to evaluate the bioaccumulation and the indirect bioindication ability of the European Hake, Merluccius merluccius (Linnaeus, 1758), one of the most important commercial fish species of the Mediterranean Sea. Morphological and histological alterations of the main target organs, such as liver and gills, have been investigated and the results showed a steatosis in the hepatic tissue. The accumulation of heavy metals has been analyzed by inductively coupled plasma mass spectrometry and for several metals it was showed a different concentration in the two sexes. Moreover, the expression of metallothioneins 1 and Heat Shock Protein 70 has been assessed by immunohistochemistry and did not show high level of expression. We underline the importance of contamination evaluation in commercial fish species and the utilization of the ichthyofauna as bioindicator of environmental quality.

Fish-Based Baby Food Concern-From Species Authentication to Exposure Risk Assessment

In this work, two different but complementary approaches were used to evaluate the reliability of fish-based baby foods as a source of safe nourishment for babies. More specifically, barcoding analysis based on the Cytochrome Oxidase I sequences was used for fish species authentication and an analysis of metal/metalloid levels was performed to estimate the exposure risk assessment derived from consumption of selected fish-based baby food in infants and toddlers. COI DNA barcoding revealed that in three samples the species detected did not match the common name of the species shown on the label. In particular, G. chalcogrammus and M. australis were found in place of M. merluccius and O. mykiss was found in place of S. salar. The analysis of exposure risk assessment indicated a low risk for developing chronic systemic and carcinogenic effects in infants and toddler, under an exposure scenario based on daily consumption of a single box of fish-based baby food. However, it is important to highlight that in order to provide a comprehensive risk assessment it would be important to supplement the levels of exposure resulting from the total diet. Overall, our results suggest that more attention should be paid by authorities to ensure the safety of food for infants and toddlers.

In vivo exposure of the marine sponge Chondrilla nucula Schmidt, 1862 to cadmium (Cd), copper (Cu) and lead (Pb) and its potential use for bioremediation purposes

The study aimed to test the cadmium (Cd), copper (Cu) and lead (Pb) bioaccumulation capacity of the marine sponge Chondrilla nucula and to measure the expression of metallothioneins (MTs) by a western blotting assay to explore metal tolerance and its potential use as a bioremediator in contaminated coastal areas. C. nucula was sampled in a protected marine area in order to perform experiments on organisms living in a healthy environment. Under laboratory conditions, the sponges were exposed to increasing concentrations of Cd, Cu and Pb in tanks filled with artificial seawater set up for the experiments. For each metal, three waterborne concentrations (mgL^-1) of Cd (0.02-0.04-0.08), Cu (0.1-0.2-0.4) and Pb (0.2-0.4-0.8) were considered separately. SPSS 20.0 was used for statistical analysis. Significant differences in bioaccumulation across levels of each metal were highlighted. Moreover, the amount accumulated in sponges increased proportionately with increasing levels of exposure for each metal as well as MT expression after Cd and Pb exposure. The results demonstrate the efficiency of C. nucula in accumulating high levels of Cu, but a low tolerance to progressively higher concentrations for Cd and Pb. The study suggests the suitability of the use of this species in bioremediation plans for moderately contaminated environments. However, the biological response in the field should be verified by the use of transplanted organisms from a control site to a polluted site.

Bioaccumulation of metals and biomarkers of environmental stress in Parablennius sanguinolentus (Pallas, 1814) sampled along the Italian coast

Heavy metal pollution is one of the greatest threats to the ecosystems because it degrades the habitat and is potentially toxic to wildlife and human populations. In the last few decades, bioaccumulation studies performed with a multimarker approach have been a valuable tool for the investigation of environmental and animal safety. We perform an analysis of a benthic teleost fish species - Parablennius sanguinolentus - sampled at several Italian coastal sites with different degrees of anthropogenic pressure. Our integrative analysis encompasses bioaccumulation of 10 metals, biomarkers of environmental stress (micronuclei and nuclear abnormalities) and neutral genetic variation (using sequences of the mtDNA control region). We find a clear and significant correlation of metal bioaccumulation with micronuclei and nuclear abnormalities, especially with undisputed genotoxic metals, such as Cd, Cr, Hg and Pb. Furthermore, the molecular genetic analysis revealed a decrease of genetic variability in the populations more subjected to anthropic pressure.

A protocol for identifying suitable biomarkers to assess fish health: A systematic review

Background

Biomarkers have been used extensively to provide the connection between external levels of contaminant exposure, internal levels of tissue contamination, and early adverse effects in organisms.

Objectives

To present a three-step protocol for identifying suitable biomarkers to assess fish health in coastal and marine ecosystems, using Gladstone Harbour (Australia) as a case study.

Methods

Prior to applying our protocol, clear working definitions for biomarkers were developed to ensure consistency with the global literature on fish health assessment. First, contaminants of concern were identified based on the presence of point and diffuse sources of pollution and available monitoring data for the ecosystem of interest. Second, suitable fish species were identified using fisheries dependent and independent data, and prioritised based on potential pathways of exposure to the contaminants of concern. Finally, a systematic and critical literature review was conducted on the use of biomarkers to assess the health of fish exposed to the contaminants of concern.

Results/Discussion

We present clear working definitions for bioaccumulation markers, biomarkers of exposure, biomarkers of effect and biomarkers of susceptibility. Based on emission and concentration information, seven metals were identified as contaminants of concern for Gladstone Harbour. Twenty out of 232 fish species were abundant enough to be potentially suitable for biomarker studies; five of these were prioritised based on potential pathways of exposure and susceptibility to metals. The literature search on biomarkers yielded 5,035 articles, of which 151met the inclusion criteria. Based on our review, the most suitable biomarkers include bioaccumulation markers, biomarkers of exposure (CYP1A, EROD, SOD, LPOX, HSP, MT, DNA strand breaks, micronuclei, apoptosis), and biomarkers of effect (histopathology, TAG:ST).

Conclusion

Our protocol outlines a clear pathway to identify suitable biomarkers to assess fish health in coastal and marine ecosystems, which can be applied to biomarker studies in aquatic ecosystems around the world.

Biomarkers assessment in the peacock blenny Salaria pavo exposed to cadmium

Cadmium (Cd) is one of the most toxic metals and is widely distributed in freshwater and marine environments. It has received much attention from a toxicological perspective. The aim of this study was to assess the effect of Cd in the peacock blenny Salaria pavo, a species of the family of blennies that was used as bioindicator of water pollution. We performed a sublethal contamination of fish to 2 mg CdCl2 L(-1) during 1, 4, 10, and 15 days. Cd accumulation was measured in gills and liver and displayed a significant increase of its concentration throughout the experiment, with slightly higher levels in the liver, except after 4 days. Partial-length cDNA of mt1, mt2, mnsod, cuznsod, cat, and gpx were characterized. Results from mRNA expression levels displayed an up-regulation of mt2 and mnsod. Biomarker activities were determined in gills and liver. In gills, data displayed an inhibition of EROD and GST activities. Cd exposure significantly increased GPx activities but did not affect CAT levels throughout the experiment. No LPO induction was observed in gills of exposed fish. Regarding the liver, the activity of all enzymes and MDA levels increased significantly from the beginning of the experiment except EROD that increased after 15 days of contamination only. At the histological level, fish exhibited pathological symptoms in gills and liver with a predominance of circulatory disturbances in gills and regressive changes in the liver. Our results displayed that peacock blennies are able to survive Cd toxicity due to various physiological adaptation mechanisms.

Ecological Risk Assessment of Metal Pollution along Greater Cairo Sector of the River Nile, Egypt, Using Nile Tilapia, Oreochromis niloticus, as Bioindicator

The present work aims to evaluate seasonal metal pollution along Greater Cairo sector of the River Nile, Egypt, using wild Nile tilapia, Oreochromis niloticus, as bioindicator and to conduct a risk assessment for human consumers. Greater Cairo is the largest populated area along the whole course of River Nile with a wide range of anthropogenic activities. Effects of metal pollution on fish body indices were studied using condition factor (CF) and scaled mass index (SMI). Metal pollution index (MPI) showed that the total metal load in fish organs followed the follwoing order: kidney > liver > gill > muscle which gives a better idea about the target organs for metal accumulation. Metal concentrations in fish muscle (edible tissue) showed the following arrangement: Fe > Zn > Cu > Mn > Pb > Cd. Metal's bioaccumulation factor (BAF) in fish muscle showed the following arrangement: Zn > Cu > Fe > Mn > Cd and Pb. The hazard index (HI) as an indicator of human health risks associated with fish consumption showed that adverse health effects are not expected to occur in most cases. However, the metals' cumulative risk effects gave an alarming sign specifically at high fish consumption rates.

Toxicity of 8-Hydroxyquinoline in Cryprinus carpio Using the Acute Toxicity Test, Hepatase Activity Analysis and the Comet Assay

To evaluate the environmental toxicity of 8-hydroxyquinoline (8-HOQ), an important industrial raw material found in China's major ornamental fish, Cryprinus carpio, using the acute toxicity test, hepatase activity analysis and the comet assay. The results indicated that 8-HOQ had significant acute toxicity in adult C. carpio with a 96 h-LC50 of 1.15 and 0.22 mg L(-1) hepatic quinoline residues as assessed by HPLC. 8-HOQ also induced genotoxicity in the form of strand breaks in the DNA of hepatic cells as shown by the comet assay. With regard to physiological toxicity, 8-HOQ induced a decrease in the activities of hepatic GOT and GPT with increased exposure concentration and time. These data suggest that 8-HOQ may be toxic to the health of aquatic organisms when accidentally released into aquatic ecosystems. The data also suggest that the comet assay may be used in biomonitoring to determine 8-HOQ genotoxicity and hepatic GPT and GOT activities may be potential biomarkers of physiological toxicity.

Spatial distribution, sources and ecological risk assessment of polycyclic aromatic hydrocarbons in surface seawater from Yangpu Bay, China

The occurrence of 14 polycyclic aromatic hydrocarbons (PAHs) listed by the United States Environmental Protection Agency was investigated in surface seawater of Yangpu Bay, China in November 2013 (winter) and May 2014 (summer). Seventy-two samples were collected from 12 sampling sites. The total concentrations of PAHs in Yangpu Bay showed obvious variations in different seasons, which varied from 582.8 to 2208.3 ng L(-1) in winter and 952.4 to 1201.7 ng L(-1) in summer, respectively. Two-ring PAHs accounted for more than 91.6% of total PAHs in winter, and three-ring PAHs were dominant with 81.6% of total PAHs in summer. Molecular indices analyses indicated that the main source of PAHs in Yangpu Bay could be petrogenic contamination. The ecological risk assessment by Risk quotients (RQNCs and RQMPCs) showed a potential ecological risk of PAHs in Yangpu Bay, indicating a close attention should be paid to pollution of PAHs in the coastal area of Yangpu.

Mercury and selenium intake by seafood from the Ionian Sea: A risk evaluation

The subject of the present study is the evaluation of the concentrations of mercury (Hg) and selenium (Se) in fish and shellfish from the Gulf of Catania (Ionian Sea) and the assessment of related risk-based consumption limits per single contaminant in adults and children. In contrast to the potential harm from Hg, Se is an essential element that is normally found in high levels in seafood. If the amount of Hg is high enough, it could bind Se and irreversibly inhibit selenium-dependent enzymes. Thus, adequate levels of Se need to be available to replace the amount of Se lost to Hg sequestration, thereby maintaining normal selenoprotein synthesis. Hg analysis was conducted using a flow injection analysis system coupled with an atomic adsorption spectrometer, and Se analysis was conducted using an inductively coupled plasma mass spectrometry (ICP-MS). Of the trace elements investigated, only Hg has a limit set by the European Community for human consumption, and this was never exceeded. Nevertheless, based on Target Hazard Quotient (THQ) over 1, and on the Estimated Daily Intake per meal (EDIm) higher than the Provisional Tolerable Intake (PTI) suggested by the Joint FAO/WHO Expert Committee on Food Additive (JECFA), Hg oral exposure derived from consumption of the benthonic fish and of the bigger pelagic fish species analyzed, could follow the occurrence of systemic effects. Se was found always in molar excess respect to Hg in all pelagic fish and in the shellfish, nearly equimolar in the benthonic fish. Determining the evidence that foods, such as pelagic fish, with high molar excess of Se, could contribute to replace the amount of Se bound to Hg and thereby maintaining normal selenoprotein synthesis, is useful for a better understanding of the seafood safety.

Seasonal variation of bioaccumulation in Engraulis encrasicolus (Linneaus, 1758) and related biomarkers of exposure

In the last years, the development of new techniques and the increase of sophisticated assays has improved the environmental monitoring programs by using fish as bioindicators of marine ecosystems, applying a multibiomarkers approach. The aim of this study was to assess the contamination level of the Catania Gulf through bioaccumulation and contaminant exposure response in Engraulis encrasicolus (Linnaeus, 1758). Heavy metals, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were analyzed in muscle tissue of the species. Furthermore we evaluated biomarkers of exposure to such contaminants: the metallothioneins (MTs), the ethoxyresorufin-O-deethylase (EROD) and stress protein or "heat shock proteins" (HSP70). In total, three sampling of 30 specimens each were performed during 2011. Comparison between classes of contaminants was performed using Student's t-test for paired samples Data showed that: the populations of E. encrasicolus accumulated a certain amount of metals, PAHs and organochlorine compounds in their tissues, that, however, did not exceed the legal limits set by Regulation 1881/2006 for contaminants in fish muscle; essential metals accumulate more during the reproductive periods of the species; the accumulation of heavy metals and PAHs are more closely related to natural and anthropogenic events; the presence of PCBs, although in traces, is the confirmation that banned compounds persist in the environment for several years; the levels of contaminants found in the tissues of the species do not seem to be likely to cause toxic effects both in the studied fish species. In conclusion, environmental risk assessment came out in this study for the Catania Gulf, showed a positive picture, although the contaminants detected are related to a certain degree of anthropic impact, and should be constantly monitored to ensure quality standards of the studied area.

Biochemical and bioaccumulation approaches for investigating marine pollution using Mediterranean rainbow wrasse, Coris julis (Linneaus 1798)

A multibiomarkers approach was used in order to estimate and monitor marine pollution. Coris julis (Linneaus, 1758) was chosen as a sentinel organism, and the specimens were collected from three well-known sites along the Ionic coast of Sicily: the protected marine area (P.M.A) "Cyclop's Islands" of Acitrezza (CT), used as a control site, Riposto (CT), and the industrial site of Augusta (SR). Abiotic levels of contaminants were also detected. High levels of biotic and abiotic accumulation were found at the industrial site in which the presence of genotoxic and oxidative damage were also evidenced, measured by Micronuclei, Alkaline and Fpg-modified Comet assays. The protein expression analysis showed metallothioneins (MTs) as good tissue-specific markers of metal accumulation. Their levels were significantly higher in muscle than in liver tissue for all the sampling sites, with a positive correlation among tissue levels and the degree of pollution at the sites. Conversely, heat shock proteins 70 (HSP70) expression was higher in Augusta and Riposto than in the control site, but no significant difference was found between the examined tissues among all sites.

Evaluation of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in Mullus barbatus from Sicily Channel and risk-based consumption limits

Our study is a preliminary step to evaluate water contamination of the Mediterranean Sea surrounding Lampedusa island and health risks for fish consumers. We analyzed muscle tissue of Mullus barbatus specimens to detect metals and polycyclic aromatic hydrocarbons (PAHs). Results show the following average concentrations of heavy metals: Pb 0.035, Cd 0.001, Hg 0.027, Cr 0.524, As 27.01, Cu 0.433, Co 0.013, Ni 0.042, Se 0.487, V 0.072, U 0.055 and Zn 3.360 ppm. PAHs ranged from 0.250 to 13.16 ppb. A possible risk to human health was determined based on consumption limits data and the content of total PAHs in fillets of this species.

Heavy metals concentrations in fish from Sicily (Mediterranean Sea) and evaluation of possible health risks to consumers

Cadmium, lead, mercury and chromium concentrations in fish muscle tissue taken from various Sicilian areas were detected. Fish caught in Siracusa, nearby a petrochemical industrial area, were more contaminated by cadmium, lead and chromium (respectively 0.366, 0.32, 0.72 μg/g) than those from the other sites. In the Sicily Channel, we found the highest bioaccumulation of mercury (0.31 μg/g). Although some metals concentrations exceed the limits set by the European regulation, the estimated weekly intake was below the Provisional Tolerable Weekly Intake established by the European Food and Safety Authority, and the Target Hazard Quotient values indicate that there is no carcinogenic risk for humans.

Levels and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in superficial sediment from 15 Italian marine protected areas (MPA)

Surface sediment from 15 Italian marine protected areas (MPA) were analysed for polycyclic aromatic hydrocarbons (PAHs). The organic carbon percentage was also determined. Total PAH concentrations (ng g⁻¹ d.w.) ranged from 0.71 (Penisola del Sinis) to 1550 (Miramare). Individual PAH analysis showed that three and four rings PAHs were the most frequently detected isomers and accounted for 60-70% of the PAH total concentrations. PAH ratio analysis showed a prevalence of pyrolytic PAH origin at most of the MPAs with exception of Porto Cesareo and Ustica where a petrogenic origin was detected. Results for organic carbon percentages ranged from 0.3% (Capo Rizzuto) to 2% (Punta Campanella). These results are comparable to other Mediterranean marine environments. However, our results shows that some MPAs, such as Miramare, Porto Cesareo, Isola Capo Rizzuto and Punta Campanella, are subject to strong pressure from urban and industrial activities where high PAH levels were detected.

Use of native species Crenicichla menezesi (Ariidae) as a model for in situ evaluation of genotoxicity in surface water

The aim of this work was to analyze the genotoxicity in surface water from the Pitimbú River (Natal, Brazil) using a neotropical species Crenicichla menezesi as bioindicator for in situ evaluation. The genotoxicity was analyzed using the micronucleus (MN) and comet assays in erythrocytes. The animals were collected from five sites of the river. A significant increase of MN frequency and comet class L1 to L4 were observed only in specimens collected from three sampling sites (SS3, SS4 and SS5) located into urban areas. These same sites also presented high metals concentration. Correlation of DNA damage and concentrations of Cu (Spearman r=0.8080), Cr (Spearman r=0.9772), and Ni (Spearman r=0.9909) were observed. These data indicate the presence of genotoxic agents. Moreover the C. menezesi species showed to be a good indicator for prompt analyses since this species presents sedentary and carnivore habits.