Survey on the presence of non-dioxine-like PCBs (NDL-PCBs) in loggerhead turtles (Caretta caretta) stranded in south Mediterranean coasts (Sicily, Southern Italy)

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.

Comparative study of polycyclic aromatic hydrocarbons (PAHs) in salt gland and liver of loggerhead turtle Caretta caretta (Linnaeus, Cheloniidae) stranded along the Mediterranean coast, Southern Italy

The levels of polycyclic aromatic hydrocarbons, PAHs, were determined in the liver and salt gland of 19 loggerhead turtles (Caretta caretta Linnaeus, Cheloniidae) stranded along the coasts of the south Tyrrhenian Sea, Italy, from 2019 to 2021. The 16 EPA's priority PAHs were determined by gas chromatography coupled with mass spectrometry (GC-MS). The average values of ΣPAHs in liver, 139 ± 55.0, were exceptionally high and up to one hundred times those of literature and appeared even more worrying in salt gland, 320 ± 97.6 ng/g, w.w. Naphthalene was the predominant contributor to PAHs richness and accounted for 90.0% and 93.7% of ΣPAHs in the two matrices, highlighting the petrogenic source of exposure. An overall higher bioaccumulation of NAP, more than two-fold, was detected in salt gland and especially in female and adults. Data of PAHs richness highlighted a potential risk of neoplastic disease development and that anthropogenic activities may seriously impair healthy state conditions of C. caretta. populations in south Tyrrhenian Sea.

Trace Elements and Persistent Organic Pollutants in Unhatched Loggerhead Turtle Eggs from an Emerging Nesting Site along the Southwestern Coasts of Italy, Western Mediterranean Sea

Marine pollution is one of the major threats affecting loggerhead turtles, which due to their long life span, highly migratory behavior, and carnivorous diet, may be exposed to elevated levels of toxic elements throughout their life. The transfer of chemicals from mothers to their offspring is of particular conservation concern because it may affect embryonic development and hatching success. In this study, the concentrations of 16 toxic and potentially toxic trace elements, 6 indicator polychlorinated biphenyls (PCBs), and organochlorine pesticide residues (OCPs) were determined in 138 eggs from 46 loggerhead turtle nests laid during the 2021 nesting season in Campania, Italy, western Mediterranean Sea. The possible impact of pollutant levels on hatching success and early embryonic death was also investigated. Trace element analysis was performed using an ICP-MS, except for mercury, which was determined using a Direct Mercury Analyzer® (DMA). PCBs and OCPs were analyzed with high-resolution gas chromatography coupled with high-resolution mass spectrometry (HRGC-HRMS) and gas chromatography tandem quadrupole mass spectrometry GC-MS /MS, respectively. The concentrations of essential elements in the eggs were higher than those of non-essential elements. In addition, the highly chlorinated PCBs (153, 138, and 180) contributed the most to the total PCBs, while OCPs were not detected. No correlations were found between contaminant concentrations and reproductive parameters (hatching success and no obvious embryos). The results obtained suggest that the levels of contaminants found in the eggs do not affect the reproductive success of the species in the study area.

Levels of non-dioxin-like PCBs (NDL-PCBs) in liver of loggerhead turtles (Caretta caretta) from the Tyrrhenian Sea (Southern Italy)

The levels of six non-dioxin-like polychlorinated biphenyls (PCBs 28, 52, 101, 138, 153, and 180) were determined in the liver of 84 loggerhead turtles (Caretta caretta) stranded along the coasts of the Tyrrhenian Sea in Campania Region (Southern Italy), from 2017 to 2021. The average value of the sum (∑₆PCB_IND) was 28.0 ± 52.2 ng/g (w.w.). The hexachlorobiphenyls PCB 153 and PCB 138 and the heptachlorobiphenyl PCB 180 were the main contributors to the ∑₆PCB_IND. A weak positive correlation was found between CCL and highly chlorinated PCBs, with adult females having lower PCB concentrations than juvenile females and adult males. This study provides more comprehensive information on the levels of NDL-PCB in Mediterranean loggerhead turtles and sets the basis for assessing anthropogenic impacts on this species.

Chlorinated Persistent Organic Pollutants (PCDD/Fs and PCBs) in Loggerhead Sea Turtles Stranded along the Central Adriatic Coast

Persistent organic pollutants are widespread in the marine environment. They can bioaccumulate and biomagnify in marine organisms through the food web with a potentially toxic effect on living organisms. The sea turtle Caretta caretta is a carnivorous animal with opportunistic feeding behavior. These turtles tend to bioaccumulate pollutants through food, and hence they can be considered an indicator of chemical pollutants in the marine ecosystem. In this study, 44 loggerhead sea turtles were considered, and liver and fat tissue were sampled from each of them to investigate the levels of dioxins (PCDD/Fs) and polychlorinated biphenyls (PCBs) in sea turtles and their potential correlation with sex and size in terms of curved carapace length (CCL). Results suggested that these contaminants were easily bioaccumulated, and PCBs were predominant compared to dioxins in both liver and fat tissue. The congener patterns were similar to those found in sea fish. Moreover, there were no differences in the contamination levels between females and males, nor was there a correlation with the size. There is a need to harmonize the methodological approaches to better evaluate the results and trends over time and to monitor the species and indirectly the health status of the marine environment.

Microplastic pollution in Marine Protected Areas of Southern Sri Lanka

Microplastics (MPs) are ubiquitous in marine environment. The prevalence of MPs in coastal and lagoon sediments, and water were studied in two Marine Protected Areas (MPAs); Bundala National Park (BNP) and Hikkaduwa Marine National Park (HNP) in Sri Lanka. Both areas are important for turtles, birds and coral ecosystems, all of which are particularly threatened by MPs. Abundance of MPs was generally higher in both coastal sediments and waters in HNP (111±29 MPs/m² for sediments and 0.515±0.054 MPs/m³ for water) than in the BNP (102±16 MPs/m² for sediments and 0.276±0.077 MPs/m³ for water). The most common shape and polymer type of MPs were fragments and Polyethylene respectively. This research is the first to survey MPs in MPAs in Sri Lanka and provides a baseline of MPs pollution in these environments for future research and management.

Polychlorinated organic pollutants (PCDD/Fs and DL-PCBs) in loggerhead (Caretta caretta) and green (Chelonia mydas) turtles from Central-Southern Tyrrhenian Sea

This study assesses for the first time the levels of PCDD/Fs and DL-PCBs in sea turtles coming from Tyrrhenian Sea. The concentrations measured in liver of the 24 specimens analysed were 6.90 vs 5.65 pg g^-1 wet weight (ww) for PCDD/Fs and 10.95 vs 0.79 ng g^-1 ww for DL-PCBs in Caretta caretta and Chelonia mydas, respectively. The DL-PCB levels resulted very higher in Caretta caretta than Chelonia mydas probably due to the different eating habits between the two species investigated. Furthermore, the highest levels of DL-PCBs were determined in livers of the adult Caretta caretta turtles of male sex. Positive correlations were found out between PCB-81 and the body mass (BM) of turtles (r² = 0.6561; p = 0.001) and between PCB-81 and the curved carapace length (CCL) (r² = 0.6250; p = 0.006) suggesting that the body burden of contaminants is related to the body size. The mean TEQ values, as a matter of risk assessment for turtles, were 3.64 vs 1.62 pg TEQ g^-1 ww for PCDD/Fs and 8.72 vs 2.16 pg TEQ g^-1 ww for DL-PCBs in Caretta caretta and Chelonia mydas, respectively. The results reported in this study increase the data available about the consequences of the Mediterranean Sea contamination by organochlorine pollutants and highlight an evident PCDD/F and PCB bioaccumulation in sea turtle tissues that threatens the survival of these marine organisms.

Protective effects of genistein on cytochrome P-450 and vitellogenin expression in liver of zebrafish after PCB-126 exposure

The objective of the research is to study the action of Vitellogenin and P-4501A1 following coexposure at different times to genistein and PCB-126 using zebrafish as a model system. Polychlorinated biphenyls are ubiquitous substances in environment. The genistein is a phytoestrogen extracted from soybeans and it's contained in food for humans and animals. For this study, 200 adult zebrafish were used. Our findings show a marked immunoreactivity of Vtg at 12h in liver than the control with only PCB-126. Regarding effects of PCB-126 on Vtg after pretreatment with genistein in fishes, the immunohistochemistry results show a minor increase at 12h. After 24h the immunoreactivity is lower than 12h and then slightly increased at 72h with only PCB-126 and PCB-126 and genistein together. CYP1A1 progressively increases from 12h to 72h in all groups with minor immunoreactivity when we treated fish with genistein and PCB-126. We show a reduction in the estrogenic effect when the fishes were treated with genistein and PCB-126 together at 12h than the group treated with only PCB-126. Moreover, low concentrations of genistein decrease the marked P450 expression induced by PCB-126. This shows that genistein decreases the expression of P450 target genes mediated by AhR.

Organic pollution in PGI and non-PGI lemons and related soils from Italy and Turkey

In this work 67 organic contaminants in Protected Geographical Indication (PGI) and non-PGI Interdonato Lemon pulps, peels, leave and related soils were evaluated by GC/MS-MS. It is possible to highlight that in Italian pulps and peels the residues were under LODs (0.10-10.30 ng·g^-1), whereas the leaves showed piperonyl butoxide in 33% of samples (11.76 ± 1.24 ng·g^-1) and cypermethrins in 33% of samples (Cypermethrin I, 6.12 ± 0.35 ng·g^-1; Cypermethrin II, 8.67 ± 0.48 ng·g^-1; Cypermethrin III, 8.90 ± 1.52 ng·g^-1; Cypermethrin IV, 12.25 ± 2.46 ng·g^-1). Turkish samples were mainly contaminated by piperonyl butoxide: it was revealed in the 33% of pulps (3.35 ± 1.03 ng·g^-1), in 100% of peels (23.46 ± 17.69 ng·g^-1) and in 100% of leaves (1302.44 ± 527.40 ng·g^-1). In both soils a different contamination was detected. This study confirms that the European brand (PGI) of Interdonato Lemon Messina is a valuable instrument for the consumer protection.

Microplastic at nesting grounds used by the northern Gulf of Mexico loggerhead recovery unit

Microplastics can impact key habitats used by endangered species, such as marine turtles. They impact the environment by transporting toxicants and altering sediment properties affecting temperature and sediment permeability. Our study determined the exposure of the ten most important nesting sites for the Northern Gulf of Mexico Loggerhead Recovery Unit to microplastic. Sand samples were obtained at each nesting site during the 2017 nesting season and analyzed for abundance and characteristics of microplastic. Microplastic was found at all sites, with an average abundance of 61.08 ± 34.61 pieces/m², and 59.9% located at the dunes, where turtles primarily nest. A gradual decrease in microplastics abundance was observed from the most western nesting ground to the east. The results from this study indicate that microplastic accumulation on nesting sites for the Northern Gulf of Mexico may be of great concern, and could negatively affect the incubating environment for marine turtles.

In vivo effects of PCB-126 and genistein on vitellogenin expression in zebrafish

In this study, the vitellogenin (Vtg) modulation by genistein and polychlorinated biphenyl-126 (PCB-126) exposure in zebrafishes has been investigated. Both PCB-126 and genistein have been identified as aquatic pollutants and can further increase estrogenicity of waterways. Vtg is egg yolk precursor protein release by the hepatocytes during vitellogenesis. This process occurs normally in the hepatocytes in response to the activation with the estrogens such as 17-β-estradiol. Our immunohistochemical findings showed a Vtg expression that increases at 12 h and at 72 h in the liver of treated fishes with both PCB-126 and genistein, individually and in combination. Furthermore, for the first time, also hepatic stellate cells (HSC) in the liver parenchyma were strongly positive for vitellogenin.