Cadmium toxicokinetics and bioaccumulation in turtles: trophic exposure of Trachemys scripta elegans

Biogenic Elements and Heavy Metals in Hermann's Tortoises-Testudo hermanni: Effect on Serum Biochemistry and Oxidative Status Parameters

BACKGROUND

Conservation of species diversity is the need of the hour for preserving life forms on Earth. Extinction of any part of the ecosystem has negative impacts on many processes and systems. The objective of this work was to analyze some biochemical and molecular indicators and their correlations to biogenic elements and heavy metals in Testudo hermanni (n = 16).

METHODS

Biochemical parameters were analyzed using the commercial kit DiaSys and biochemical analyzer Randox RX Monza. Sodium, potassium, and chlorides were measured using the EasyLite analyzer. Oxidative stress was evaluated using colorimetric and luminometric methods. Quantification of chemical elements in the blood was carried out using inductively coupled plasma mass spectrometry (ICPS).

RESULTS

Biochemical values of analyzed samples from Hermann's tortoises were almost the same as referential values described by multiple authors, with minor aberrations in the total protein parameter. Values of arsenic (As) and nickel (Ni) showed correlation with biochemical parameters and the parameters of oxidative stress. Cadmium (Cd) exhibited correlation with aspartate aminotransferase (AST).

CONCLUSIONS

This study reports correlations among four heavy metals, and their levels were again correlated with biochemical and molecular parameters in Hermann's tortoises.

Effects of Cadmium on Kidney Function of the Freshwater Turtles Mauremys reevesii

This research studied the effects of cadmium on kidney function of the freshwater turtles Mauremys reevesii. Turtles were injected intraperitoneally with 0, 7.5, 15, and 30 mg kg^-1 cadmium separately for once. The samples were gathered to check the kidney index, the contents of TP in kidney tissue, and the levels of CRE and BUN in the plasma of the turtles. Results showed that the concentration of TP was overall decreased with the extension of cadmium exposure time and the increasing of the exposure dose of cadmium. The CRE content in the plasma of each treatment group increased with the prolongation of exposure time in a dose-dependent, and the BUN levels of all poisoned groups showed a trend of increasing. The kidney index of treated turtles increased. In summary, cadmium could induce the increase of turtle kidney index, the content of CRE and BUN in plasma, and the decrease of TP content in the kidney.

Transfer and accumulation of trace elements in seawater, sediments, green turtle forage, and eggshells in the Xisha Islands, South China Sea

Chemical pollutants present a substantial threat to the survival of the green turtle (Chelonia mydas). In this study, the concentrations of 12 trace elements (TEs) in seawater, sediments, and green turtle forage and eggshells from the Xisha Islands in the South China Sea, along with their patterns of transfer and accumulation, were identified. The results revealed that the median TE concentrations in seawater and sediments were lower than the first-grade limit values of the national standard in China, indicating a low ecological risk. The concentrations (μg·g-1) of TEs in forage ranged from 0.05-0.69, 3.43-14.4, 157-2391, 27.9-124, 2.05-9.39, 0.30-9.78, 2.01-80.50, 0.18-5.76, 0.06-0.98, 2.00-18.4, 0.02-0.24, and 0.01-0.09 for Cr, Mn, Sr, Fe, Ni, Cu, Zn, Se, Cd, As, Pb, and Hg, respectively. Seawater, sediments, turtle forage, and eggshells exhibited different TE profiles, which were driven by Hg, Sr, Cr, and Pb in seawater and sediments; Fe and Ni in sediments; Cd and As in forage; and Zn, Se, and Cu in eggshells. The contents of Cu, Zn, and Se increased slightly with trophic level, indicating that they were transferred through dietary pathways. Although Cd and As appeared to bioaccumulate in green turtle forage, it was not transferred to their eggshells, which may be related to the excretion and metabolism process in the mother's body. Thus, eggshells may be a poor bioindicator for the exposure of female green turtles to these toxic elements.

Stress response markers in the blood of São Tomé green sea turtles (Chelonia mydas) and their relation with accumulated metal levels

Metals are persistent worldwide being harmful for diverse organisms and having complex and combined effects with other contaminants in the environment. Sea turtles accumulate these contaminants being considered good bioindicator species for marine pollution. However, very little is known on how this is affecting these charismatic animals. São Tomé and Príncipe archipelago harbours important green sea turtle (Chelonia mydas) nesting and feeding grounds. The main goal of this study was to determine metal and metalloid accumulation in the blood of females C. mydas nesting in São Tomé Island, and evaluate the possible impacts of this contamination by addressing molecular stress responses. Gene expression analysis was performed in blood targeting genes involved in detoxification/sequestration and metal transport (mt, mtf and fer), and in antioxidant and oxidative stress responses (cat, sod, gr, tdx, txrd, selp and gclc). Micronuclei analysis in blood was also addressed as a biomarker of genotoxicity. Present results showed significant correlations between different gene expressions with the metals evaluated. The best GLM models and significant relationships were found for mt expression, for which 78% of the variability was attributed to metal levels (Al, Cu, Fe, Hg, Pb and Zn), followed by micronuclei count (65% - Cr, Cu, Fe, Hg, Mn and Zn), tdx expression (52% - Cd, Fe, Mn, Pb and Se), and cat expression (52% - As, Fe, Se and Cd x Hg). Overall, this study demonstrates that these green sea turtles are trying to adapt to the oxidative stress and damage produced by metals through the increased expression of antioxidants and other protectors, which raises concerns about the impacts on these endangered organisms' fitness. Furthermore, promising biomarker candidates associated to metal stress were identified in this species that may be used in future biomonitoring studies using C. mydas' blood, allowing for a temporal follow-up of the organisms.

An integrative approach to define chemical exposure threshold limits for endangered sea turtles

Environmental contaminants pose serious health threats to marine megafauna species, yet methods defining exposure threshold limits are lacking. Here, a three-pillar chemical risk assessment framework is presented based on (1) species- and chemical-specific lifetime bioaccumulation modelling, (2) non-destructive in vitro and in vivo toxicity threshold assessment, and (3) chemical risk quantification. We used the effects of cadmium (Cd) in green sea turtles (Chelonia mydas) as a proof of concept to evaluate the quantitative mechanistic modelling approach. A physiologically-based kinetic (PBK) model simulated Cd tissue concentrations (liver, kidney, muscle, fat, brain, scute, and 'rest of the body') in C.mydas. The validated PBK model then translated species-specific in vitro results to in vivo effects. The results showed that the resilience of C.mydas towards Cd kidney toxicity is age-dependent and differs with changing physiology and feeding ecology. Using the model in reverse mode, a steady-state exposure threshold of 0.1 µg/g dry weight Cd in forage was derived and compared to real-world exposure scenarios. Three out of the four globally distinct C.mydas populations assessed are exposed to Cd levels above this threshold limit. This approach can be adapted to other marine species and chemicals to prioritize measures for managing potentially harmful chemical exposures.

Freshwater aquatic reptiles (Testudines and Crocodylia) as biomonitor models in assessing environmental contamination by inorganic elements and the main analytical techniques used: a review

Despite the general lack of studies that use reptiles as bioindicators, the value of freshwater turtles and crocodilians in ecotoxicology has been proven, due to their importance as sentinel species. The aim of this study was to compile information on the use of freshwater turtles and crocodilians as environmental biomonitors of inorganic element contamination. We searched for articles in databases using specific keywords. A total of 104 studies published between the years 1970 and 2020 were collected. We noted a general increase in the number of studies involving turtles and crocodilians during the study time period. The Order Testudines were the subjects of 46% of the analysed publications, and the Order Crocodylia accounted for 54%. Within these studies, we counted 39 species (turtles n = 29 and crocodilians n = 10). Forty chemical elements were evaluated in the analysed articles, of which the majority represented non-essential elements (Hg, Cd, Pb). Although internal organs constituted the main biological matrix chosen for each group (37%), we observed an increase in the use of non-destructive matrices in both groups (scale, blood, tail muscle, carapace). The majority of analysed studies used HNO₃ for the sample decomposition, with the majority of analyses being performed using atomic absorption spectroscopy (53%). Mainly blank controls (19%), analyte recovery (18%) and replicates (18%) were used as methods of validating analytical procedures. Furthermore, the studies used certified reference materials, which measure the accuracy of the methods used. We conclude that the increase in the use of aquatic reptiles in environmental monitoring research is mainly due to their ability to reveal integrated changes in ecosystems, aiding in environmental public policy decision-making and effective management plans.

Concentrations of trace elements in tissues of loggerhead turtles (Caretta caretta) from the Tyrrhenian and the Ionian coastlines (Calabria, Italy)

Toxic trace elements from both, natural and anthropogenic origin, pose a threat to aquatic environments and marine wildlife due to their long-range transport, bioaccumulative nature, and biomagnification through the food chain. Being long-lived and migratory animals, sea turtles can be exposed to elevated levels of toxic elements, and are therefore considered sentinel species for chemical pollution. In this study, concentrations of trace elements (arsenic, cadmium, lead, mercury) were determined in tissues of 46 loggerhead sea turtles (Caretta caretta) stranded along Tyrrhenian and Ionian coasts of Calabria, in Southern Italy, between 2014 and 2020. Curved carapace length (CCL), curved carapace width (CCW), body mass (BM), and sex were determined and the correlations of these parameters with toxic elements concentrations were investigated. During necropsy, kidney, liver, and muscle tissues were collected and the concentration and distribution of metals determined. Muscle tissues showed the lowest toxic element burdens, except for As that showed the highest mean concentrations in this tissue. The kidney was the main accumulation organ for Cd, while similar levels of Hg and Pb were measured in kidney, liver, and muscle tissues. The risk assessment performed for Cd, Hg, and Pb in sea turtles' liver highlighted possible negative effects on sea turtles' health and the need for marine turtle toxicology researches. This is the first study reporting levels and distribution of toxic elements in tissues of Caretta caretta turtles from the Tyrrhenian and Ionian coasts of Calabria.

Lipid peroxidation of kidney of the turtle Mauremys reevesii caused by cadmium

This research was designed to investigate lipid peroxidation of the kidney of turtle (Mauremys reevesii) caused by cadmium. Turtles were injected intraperitoneally with cadmium at the concentration of 0 (control), 7.5, 15, and 30 mg/kg, and 5 turtles were taken from each group after exposure for 1 week (1 w), 2 weeks (2 w), and 3 weeks (3 w). Superoxide dismutase (SOD) and catalase (CAT) activities as well as glutathione (GSH) and malonyldialdehyde (MDA) contents in the homogenate of kidney tissue were analyzed. The results demonstrated that a short time of low dose of cadmium could stimulate the increase of SOD activity in the kidney of turtles, but a long time of high dose of cadmium could induce the decrease of SOD activity in the kidney of turtles. Cadmium could decrease CAT activity and GSH content in turtle kidney, but increased MDA content in turtle kidney. There were some other effects on the turtles, such as depression and diarrhea. The experimental results indicate that cadmium causes temporary oxidative stress on the kidney of turtles.

Effects of cadmium on the activities of ALT and AST as well as the content of TP in plasma of freshwater turtle Mauremys reevesii

Cadmium (Cd) is one of the toxic metals in the aquatic environment. This study was designed to examine the effects of Cd on the activities of ALT and AST and the concentrations of TP in plasma of freshwater turtle Mauremys reevesii. Experiment turtles were exposed to Cd at the concentration of 15 mg/kg by intraperitoneal injection. The activities of ALT and AST and the concentrations of TP were investigated. Compared with the controls, the activities of ALT and AST in plasma of the treated turtles significantly increased. The concentrations of TP were comparable between the treated turtles and the controls except that were higher than the control turtles in 14 days (14 d) and 56 days (56 d). As a result that turtles exposed to Cd were led to liver function damage.

Effects of cadmium on the gene transcription of the liver in the freshwater turtle (Chinemys reevesii)

This study investigated the related gene transcription of liver in freshwater turtle Chinemys reevesii exposed to cadmium (Cd). After acclimation, healthy turtles were selected for experiments. They were randomly divided into four experimental groups and each group had 5 animals. The turtles were treated with 0 mg/kg, 7.5 mg/kg, 15 mg/kg, and 30 mg/kg Cd chloride separately by intraperitoneal injection. Liver samples were collected for examination of the transcription of related genes at 2 weeks after Cd exposure. The transcription of mRNA of MT, SOD, CAT, PNKP, and GPX4 genes in turtle liver cells were analyzed. Results showed that Cd promoted MT mRNA transcription in turtle's liver at low dose (7.5 mg/kg) and inhibited MT mRNA transcription in turtle's liver at middle dose (15 mg/kg) and high dose (30 mg/kg). Cd inhibited the transcription of SOD, CAT, and PNKP mRNA in turtle's liver, and the inhibition was obvious at high dose (30 mg/kg). Cd promoted GPX4 mRNA transcription in turtle's liver, especially at low dose (7.5 mg/kg). In conclusion, Cd had different effects on the mRNA transcription of liver cells in the freshwater turtle Chinemys reevesii exposed to Cd.

A turtle population study in an isolated urban wetland complex in Ontario reveals a few surprises

We report on the results of the first mark–recapture survey of freshwater turtles in an isolated urban wetland complex in one of Canada’s fastest growing municipalities. Although we found turtles in every surveyed wetland, the density and assemblage of turtles in smaller wetlands were significantly different than in larger wetland bodies. We also documented two species of turtles that were thought to be absent from this wetland complex, the Northern Map turtle and Eastern Musk turtle. We noted that a wetland that was bisected by a high-traffic road showed a male-skewed sex ratio in the population of Midland Painted turtles but not in the population of Eastern Snapping turtles. As a whole, the sex ratios inside the wetland complex were not skewed. These results reinforce the conclusions of a previous study of a single wetland within this same complex that had found a correlation between road mortality and a male-skewed sex ratio in Midland painted turtles. We discuss population sources and sinks within the complex and the importance of protecting the overland corridors that support the safe turtle movements within this provincially significant wetland complex.

Elucidating temporal trends in trace element exposure of green turtles (Chelonia mydas) using the toxicokinetic differences of blood and scute samples

Blood is considered a suitable biomonitoring matrix for evaluating relatively recent exposure to environmental contaminants since abrupt changes in exposure regimes are rapidly reflected in blood. On the other hand, keratinized tissues, such as turtle scutes, are known to integrate trace element exposure over relatively long time periods. This study aimed to test the use of the differences in blood and scute to inform on the historical trace element exposure of green turtles. We propose a blood-scute kinetic model to predict how an increase in exposure would affect the concentrations in these two matrices over time. We then tested the relationship between blood and scute concentrations for 19 trace elements in two green turtle populations presumed to experience relatively constant exposure conditions. Significant log-log and linear correlations were observed between blood and scute concentrations for Co, As, Mo, Sb, and Cd. We then analysed blood-scute ratios in turtles from two coastal sites with known elevated exposure to various trace elements from previous studies. Deviations from the steady-state were clearly evident in these coastal turtles (for Co and Cd) and were consistent with the model prediction of changes in exposure. These field data provide evidence that blood-scute ratios can provide a valuable tool for examining the historical trace element exposure of turtles. We further present a method by which the general model may be refined and validated, by using data from individual turtles that had been recaptured across multiple years. Although the timeframe and number of recaptured samples available for this study were limited, the temporal changes in blood-scute ratios in these animals were generally consistent with those suggested by the model. Thus, the ratio between paired blood and scute trace element concentrations could be used to establish a temporal exposure index in turtles.

Effects of cadmium on oxidative stress activities in plasma of freshwater turtle Chinemys reevesii

Cadmium (Cd) has been recently found in high concentrations in the aquatic environment. This study was designed to examine the effects of Cd on the oxidative stress activities in plasma of freshwater turtle Chinemys reevesii. Experimental turtles were exposed to Cd at the concentration of 15 mg/kg by intraperitoneal injection, and redox status was investigated. Compared to the controls, superoxide dismutase (SOD) and catalase activities in plasma of the treated animals significantly decreased in week 1, week 2, and week 4. However, SOD activities gradually increased from week 4 to week 8. The treated animals had higher content of MDA and lower content of GSH in plasma over the observation period. In conclusion, our results showed that Cd decreased the antioxidant capacity and increased the level of oxidative damage product in plasma, which suggest that Cd causes oxidative stress and damage in the animal under the experimental conditions.

Toxic elements and associations with hematology, plasma biochemistry, and protein electrophoresis in nesting loggerhead sea turtles (Caretta caretta) from Casey Key, Florida

Toxic elements (arsenic, cadmium, lead, mercury, selenium, thallium) are a group of contaminants that are known to elicit developmental, reproductive, general health, and immune system effects in reptiles, even at low concentrations. Reptiles, including marine turtles, are susceptible to accumulation of toxic elements due to their long life span, low metabolic rate, and highly efficient conversion of prey into biomass. The objectives of this study were to (1) document concentrations of arsenic, cadmium, lead, mercury, selenium, and thallium in whole blood and keratin from nesting loggerhead sea turtles (Caretta caretta) from Casey Key, Florida and document correlations thereof and (2) correlate whole blood toxic element concentrations to various hematological and plasma biochemistry analytes. Baselines for various hematological and plasma analytes and toxic elements in whole blood and keratin (i.e., scute) in nesting loggerheads are documented. Various correlations between the toxic elements and hematological and plasma biochemistry analytes were identified; however, the most intriguing were negative correlations between arsenic, cadmium, lead, and selenium with and α- and γ-globulins. Although various extrinsic and intrinsic variables such as dietary and feeding changes in nesting loggerheads need to be considered, this finding may suggest a link to altered humoral immunity. This study documents a suite of health variables of nesting loggerheads in correlation to contaminants and identifies the potential of toxic elements to impact the overall health of nesting turtles, thus presenting important implications for the conservation and management of this species.

Cadmium induces histopathological injuries and ultrastructural changes in the liver of freshwater turtle (Chinemys reevesii)

The study investigated the histopathological and ultrastructural lesions of liver of freshwater turtle Chinemys reevesii exposed to Cadmium (Cd). The animals were exposed to 0 mg kg^-1 (0.85% normal saline (NS)), 7.5 mg kg^-1, 15 mg kg^-1, 30 mg kg^-1 Cd chloride separately by intraperitoneal injection. Liver samples were collected for examination of lesions under light and electronic microscopes. Results showed that liver tissues from Cd -treated animals presented various degrees of histopathological lesions. Liver cells showed swollen, degeneration and necrosis with dose-dependent manner. Under electronic microscope, nucleus, mitochondria and rough endoplasmic reticulum presented various degrees of lesions with dose-dependent manner. In conclusion, Cd has significant toxicity on liver tissue of the freshwater turtle, which occurs in a dose-dependent manner.

The current situation of inorganic elements in marine turtles: A general review and meta-analysis

Inorganic elements (Pb, Cd, Hg, Al, As, Cr, Cu, Fe, Mn, Ni, Se and Zn) are present globally in aquatic systems and their potential transfer to marine turtles can be a serious threat to their health status. The environmental fate of these contaminants may be traced by the analysis of turtle tissues. Loggerhead turtles (Caretta caretta) are the most frequently investigated of all the sea turtle species with regards to inorganic elements, followed by Green turtles (Chelonia mydas); all the other species have considerably fewer studies. Literature shows that blood, liver, kidney and muscle are the tissues most frequently used for the quantification of inorganic elements, with Pb, Cd, Cu and Zn being the most studied elements. Chelonia mydas showed the highest concentrations of Cr in muscle (4.8 ± 0.12), Cu in liver (37 ± 7) and Mg in kidney (17 μg g^-1 ww), Cr and Cu from the Gulf of Mexico and Mg from Japanese coasts; Lepidochelys olivacea presented the highest concentrations of Pb in blood (4.46 5) and Cd in kidney (150 ± 110 μg g^-1 ww), both from the Mexican Pacific; Caretta caretta from the Mediterranean Egyptian coast had the highest report of Hg in blood (0.66 ± 0.13 μg g^-1 ww); and Eretmochelys imbricata from Japan had the highest concentration of As in muscle (30 ± 13 13 μg g^-1 ww). The meta-analysis allows us to examine some features that were not visible when data was analyzed alone. For instance, Leatherbacks show a unique pattern of concentration compared to other species. Additionally, contamination of different tissues shows some tendencies independent of the species with liver and kidney on one side and bone on the other being different from other tissues. This review provides a general perspective on the accumulation and distribution of these inorganic elements alongside existing information for the 7 sea turtle species.

Cadmium toxicokinetics in the freshwater turtle, Chinemys reevesii

This study was designed to investigate the toxicokinetics of Cadmium (Cd) in Chinemys reevesii. The animals were exposed to 15 mg/kg Cd chloride by intraperitoneal injection, and the Cd absorption, distribution, and excretion in different organs were determined. The results showed that Cd absorption reached its peak in the blood at 3 h after treatment. The accumulation of Cd was the highest in the liver and the second highest in the pancreas. All other tissues also accumulated Cd, such as spleen, kidney, intestine, lung, stomach, heart, brain, muscle. A small amount of Cd was found in the faeces. The urine and bile had low concentrations of Cd. In conclusion, absorbance of Cd reaches its peak at 3 h in blood. The liver and pancreas are the major organs of Cd accumulation, and the major excretion route of Cd is through feaces.

Morphologic and Cytochemical Characteristics of the Blood Cells of the Yellow-Bellied Slider (Trachemys scripta scripta)

The increasing prevalence of yellow-bellied sliders (Trachemys scripta scripta) as pets in the European Union and also its utilization as animal models for experimental purposes makes crucial an accurate classification of their blood cells. The aim of this work was to provide a morphologic classification based on the cytochemical characteristics of the blood cells of 15 yellow-bellied sliders. Cytochemical stains included benzidine peroxidase, chloroacetate esterase, alpha-naphthyl butyrate esterase (with and without sodium fluoride), acid phosphatase (with and without tartaric acid), Sudan black B, periodic acid-Schiff and toluidine blue. Nuclear and cellular dimensions were also measured based on quick Romanowsky-type stained smears. Besides erythrocytes and thrombocytes, five types of white blood cells were identified: heterophils, eosinophils, basophils, lymphocytes and monocytes. The cytochemical patterns of heterophils, eosinophils and basophils were unique compared to those described for other chelonians. This paper provides a useful guideline for clinical settings and further haematological studies of this species.

Influence of a Former Mining Area in the Heavy Metals Concentrations in Blood of Free-Living Mediterranean Pond Turtles (Mauremys leprosa)

The objective of this study was to assess metal exposure in the Mediterranean Pond Turtle (Mauremys leprosa) inhabiting a watercourse in an ancient mining district polluted by different metals ("Rambla de Las Moreras", southeastern Spain) and included in the Ramsar Convention. For this purpose, mercury (Hg), lead (Pb), copper (Cu), zinc (Zn) and cadmium (Cd) were analysed in blood samples from 42 M. leprosa healthy adults (27 males and 13 females). The highest median concentrations were found for Zn, followed by Cu, Pb, Hg and Cd (366, 33, 9, 0.83 and 0.14 µg/dL, respectively). Although the literature regarding toxic metals in freshwater turtles is relatively scarce, Pb may cause deleterious effects in our population. In general, males presented higher levels than females, which could be due to maternal transfer during egg formation. The significant correlations between Cu-Cd and Cu-Hg suggest the implication of an efficient mechanism of detoxification involving metallothioneins.

Trace elements in loggerhead turtles (Caretta caretta) stranded in mainland Portugal: Bioaccumulation and tissue distribution

Pollution is among the most significant threats that endanger sea turtles worldwide. Waters off the Portuguese mainland are acknowledged as important feeding grounds for juvenile loggerheads. However, there is no data on trace element concentrations in marine turtles occurring in these waters. We present the first assessment of trace element concentrations in loggerhead turtles (Caretta caretta) occurring off the coast of mainland Portugal. Also, we compare our results with those from other areas and discuss parameters that may affect element concentrations. Trace element concentrations (As, Cd, Cu, Pb, Mn, Hg, Ni, Se, Zn) were determined in kidney, liver and muscle samples from 38 loggerheads stranded between 2011 and 2013. As was the only element with higher concentrations in muscle (14.78 μg g^-1 ww) than in liver or kidney. Considering non-essential elements, Cd presented the highest concentrations in kidney (34.67 μg g^-1) and liver (5.03 μg g^-1). Only a weak positive link was found between renal Cd and turtle size. Inter-elemental correlations were observed in both liver and kidney tissues. Hepatic Hg values (0.30 ± 0.03 μg g^-1) were higher than values reported in loggerheads in the Canary Islands but lower than in Mediterranean loggerheads. Cd concentrations in the present study were only exceeded by values found in turtles from the Pacific. Although many endogenous and exogenous parameters related with complex life cycle changes and wide geographic range may influence trace element accumulation, the concentrations of Cd are probably related to the importance of crustaceans in loggerhead diet in the Portuguese coast.

Trace element reference intervals in the blood of healthy green sea turtles to evaluate exposure of coastal populations

Exposure to essential and non-essential elements may be elevated for green sea turtles (Chelonia mydas) that forage close to shore. Biomonitoring of trace elements in turtle blood can identify temporal trends over repeated sampling events, but any interpretation of potential health risks due to an elevated exposure first requires a comparison against a baseline. This study aims to use clinical reference interval (RI) methods to produce exposure baseline limits for essential and non-essential elements (Na, Mg, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Sb, Ba, and Pb) using blood from healthy subadult turtles foraging in a remote and offshore part of the Great Barrier Reef. Subsequent blood biomonitoring of three additional coastal populations, which forage in areas dominated by agricultural, urban and military activities, showed clear habitat-specific differences in blood metal profiles relative to the those observed in the offshore population. Coastal turtles were most often found to have elevated concentrations of Co, Mo, Mn, Mg, Na, As, Sb, and Pb relative to the corresponding RIs. In particular, blood from turtles from the agricultural site had Co concentrations ranging from 160 to 840 μg/L (4-25 times above RI), which are within the order expected to elicit acute effects in many vertebrates. Additional clinical blood biochemistry and haematology results indicate signs of a systemic disease and the prevalence of an active inflammatory response in a high proportion (44%) of turtles from the agricultural site. Elevated Co, Sb, and Mn in the blood of these turtles significantly correlated with elevated markers of acute inflammation (total white cell counts) and liver dysfunction (alkaline phosphatase and total bilirubin). The results of this study support the notion that elevated trace element exposures may be adversely affecting the health of nearshore green sea turtles.

Ultrastructural characteristics of blood cells in the Yellow-Bellied Slider Turtle (Trachemys scripta scripta)

BACKGROUND

The classification of blood cells from the Yellow-Bellied Slider Turtle (Trachemys scripta scripta) is relevant due to their increasing importance as pets and as object of study in clinical settings and research projects. However, no previous ultrastructural characterization of blood cells from turtles of the genus Trachemys has been reported.

OBJECTIVES

The objective of this study was to provide an ultrastructural characterization of blood cells of the Yellow-Bellied Slider Turtle.

METHODS

Blood samples from 10 healthy adult turtles (5 males and 5 females) were obtained and processed for transmission electron microscopy using standard methods.

RESULTS

Some erythrocytes had intracytoplasmic inclusions compatible with hemoglobin precipitates; mitochondria and ribosomes in the cytoplasm of erythrocytes were also observed. Five types of white blood cells were ultrastructurally identified: heterophils, eosinophils, basophils, lymphocytes, and monocytes. Heterophils were similar to those described from Sea Turtles, with only one morphologic variation of this cell. Eosinophils were homogeneous in size and had intracytoplasmic granules without crystalline structures. Basophils were ultrastructurally described for the first time for a turtle and had heterogeneous intracytoplasmic granules. Lymphocytes and monocytes were similar to those described from other chelonians. Some thrombocytes had an irregularly lobulated nucleus and intracytoplasmic canalicular structures.

CONCLUSION

This study provides the first ultrastructural classification of blood cells in Trachemys scripta scripta, as a baseline for further hematologic studies in this species.

Amelioration Effect of Zinc and Iron Supplementation on Selected Oxidative Stress Enzymes in Liver and Kidney of Cadmium-Treated Male Albino Rat

Cadmium (Cd) is a highly toxic, nonessential heavy metal with many industrial uses that can contribute to a well-defined spectrum of diseases in animals as well as in humans. The present study examines the effect of zinc (Zn) and iron (Fe) supplementation on oxidative stress enzymes in Cd-treated rats. Wistar strain male albino rats were treated with cadmium chloride (CdCl2) at a dose of 1/10(th) LD50/48 h, that is, 22.5 mg/kg body weight for 7, 15, and 30 days (d) time intervals. The 15d Cd-treated rats were divided into three groups. The first group received Zn (12 mg/kg), second group Fe (40 mg/kg) alone, and third group supplemented with both Zn and Fe and observed for 7, 15, and 30d. After the specific time intervals, rats were decapitated and oxidative stress enzymes like catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione S-transferase (GST) were assayed in liver and kidney. Simultaneously lipid peroxidation (LPO) levels were also measured. A significant elevation in LPO levels with decreased activity levels of CAT, SOD, GPx, and GST were observed during Cd intoxication. With Zn and/or Fe supplementation, a significant reversal in the oxidative stress enzymes was observed. Our study reveals that combination of Zn and Fe supplementation is effective in detoxifying the Cd body burden from the test tissues.

Assessment trace elements concentrations in tissues in Caspian Pond Turtle (Mauremys caspica) from Golestan province, Iran

Concentrations of cadmium, lead, zinc, and copper were measured in different organs and tissues of 15 Caspian Pond Turtle (Mauremys caspica) collected from Gharehsu River, Golestan province, Iran in June and July 2012. Mean concentrations (dry weight) of zinc and copper were 66.9 and 6.7µgg(-1) in liver, 147 and 3.4µgg(-1) in heart, 93.2 and 4.9µgg(-1) in shell, and finally 150.7 and 4.5µgg(-1) in muscle, respectively. Mean concentrations of cadmium and lead were 5.8 and 32.4µgg(-1) in liver, 2.9 and 20.9µgg(-1) in heart, 3.5 and 21.5µgg(-1) in shell, and finally 2.5 and 27.5µgg(-1) in muscle, respectively. On average, lead, cadmium, copper and zinc concentrations in the analyzed tissues were much higher than those reported in other freshwater turtle species. In particular, the mean concentrations of lead in liver and muscle of Caspian Pond Turtle was extremely high. To our knowledge, this is the first report into metal accumulation in tissues and organs of Caspian Pond Turtle from of the Gharehsu River in Golestan province, Iran.