Toxicological effects of polychlorinated biphenyls (PCBs) on freshwater turtles in the United States

Decrypting the skeletal toxicity of vertebrates caused by environmental pollutants from an evolutionary perspective: From fish to mammals

The rapid development of modern society has led to an increasing severity in the generation of new pollutants and the significant emission of old pollutants, exerting considerable pressure on the ecological environment and posing a serious threat to both biological survival and human health. The skeletal system, as a vital supportive structure and functional unit in organisms, is pivotal in maintaining body shape, safeguarding internal organs, storing minerals, and facilitating blood cell production. Although previous studies have uncovered the toxic effects of pollutants on vertebrate skeletal systems, there is a lack of comprehensive literature reviews in this field. Hence, this paper systematically summarizes the toxic effects and mechanisms of environmental pollutants on the skeletons of vertebrates based on the evolutionary context from fish to mammals. Our findings reveal that current research mainly focuses on fish and mammals, and the identified impact mechanisms mainly involve the regulation of bone signaling pathways, oxidative stress response, endocrine system disorders, and immune system dysfunction. This study aims to provide a comprehensive and systematic understanding of research on skeletal toxicity, while also promoting further research and development in related fields.

Morphological variations and demographic responses of the Mediterranean pond turtle Mauremys leprosa to heterogeneous aquatic habitats

Human activities affect terrestrial and aquatic habitats leading to changes at both individual and population levels in wild animal species. In this study, we investigated the phenotype and demographics of the Mediterranean pond turtle Mauremys leprosa (Schweigger, 1812) in contrasted environments of Southern France: two peri-urban rivers receiving effluents from wastewater treatment plants (WWTP), and another one without sewage treatment plant. Our findings revealed the presence of pesticides and pharmaceuticals in the three rivers of investigation, the highest diversities and concentrations of pollutants being found in the river subsections impacted by WWTP effluents. Principal component analysis and hierarchical clustering identified three levels of habitat quality, with different pollutant concentrations, thermal conditions, nutrient, and organic matter levels. The highest turtle densities, growth rates, and body sizes were estimated in the most disturbed habitats, suggesting potential adult benefits derived from harsh environmental conditions induced by pollution and eutrophication. Conversely, juveniles were the most abundant in the least polluted habitats, suggesting adverse effects of pollution on juvenile survival or adult reproduction. This study suggests that turtles living in polluted habitats may benefit from enhanced growth and body size, at the expense of reproductive success.

Partitioning of PFAS to serum, tissues, eggs, and hatchlings of an Australian freshwater turtle

Turtles are a potential sentinel species of aquatic ecosystem health as they inhabit aquatic ecosystems, are long lived, and potentially have high exposure to anthropogenic chemicals via food and water. This study investigated per- and polyfluoroalkyl substances (PFAS) tissue partitioning in female Emydura macquarii macquarii turtle, and the maternal offloading of (PFAS) into eggs and then hatchlings as well as the accumulation of PFAS in male and female Emydura macquarii macquarii serum. Significantly higher levels of perfluorosulfonic acids (PFSAs) and perfluorocarboxylic acids (PFCAs) were measured in the male serum compared to the female turtle serum, whereas perfluoroalkane sulfonamides (FASAs) were significantly higher in the female turtle serum. Perfluorooctane sulfonate (PFOS) was the predominant PFAS in the turtles whereas PFHxA was the predominant PFAS found in the surrounding water. PFHxA was not reported in any turtle tissue or the serum. The short-chain PFSAs and FASAs appeared to be highly associated with blood; long-chain PFSAs and PFCAs were more likely to be associated with tissue. Half of the PFHxS and all the long-chain PFSAs and PFCAs reported in the yolks were transferred into the hatchlings (by mass), suggesting a potential intergenerational effect.

Comparative toxic effect of ammonia exposure on Mauremys sinensis and invasive species Trachemys scripta elegans

As one of main pollutants, ammonia could cause adverse effects to aquatic animals. To explore the toxic effects of ammonia on Chinese striped-necked turtles (Mauremys sinensis) and invasive species red-eared slider (Trachemys scripta elegans), we compared the activities of antioxidant enzymes, the mRNA levels of genes involved in immune status, endoplasmic reticulum stress and apoptosis between T. s. elegans and M. sinensis under ammonia exposure for 30 days. The results showed that ammonia obviously increased the activities of SOD, CAT, GPX and T-AOC in both T. s. elegans and M. sinensis, especially CAT and GPX in T. s. elegans were higher than that in M. sinensis. The expression levels of JAK, RELA and Mcl-1 in T. s. elegans obviously increased, while IL-6 mRNA levels significantly increased in M. sinensis. In addition, Bip and IRE1 levels in M. sinensis showed a marked increase, and were significantly higher than that in T. s. elegans. Bcl-2 and Bcl-xL transcriptional levels in T. s. elegans showed an increase, especially Bcl-xL were significantly higher than that in M. sinensis. These results indicated that T. s. elegans exhibited more stronger antioxidant defense and immune function than M. sinensis under ammonia exposure. M. sinensis was more likely to occur endoplasmic reticulum stress and inflammation in ammonia environment. This research reveals the physiological response of turtles to ammonia, helps to understand adverse effects of environmental pressure on aquatic turtles, and further explains the tolerance of invasive species T. s. elegans to environmental pollution.

Effects of butyl paraben on behavior and molecular mechanism of Chinese striped-necked turtle (Mauremys sinensis)

Butyl paraben (BuP) is widely used in cosmetics, drugs, and food preservation. Recently it is an identified new pollutant that affects various aspects of reproduction, lipid metabolism, and nervous system. Behavioral activity serves as a pre-warning biomarker for predicting water quality. So, in this study, the changes in some behaviors and its neurotransmitters and cell apoptosis in the brain of Chinese striped-necked turtles (Mauremys sinensis) were studied when the turtles were exposed to BuP concentrations of 0, 5, 50, 500, and 5000 µg/L for 21 weeks. The results showed that, the basking time and altering scores to external stimuli in the groups of 50, 500, and 5000 µg/L were significantly reduced, while the time for body-righting was significantly increased, compared with the control (0 µg/L), indicating that the turtles exhibited depression and inactive behavior. The analysis of neurotransmitter in the brain showed that 5-hydroxytryptamine (5-HT) contents in the groups of 500 and 5000 µg/L were significantly higher than the other groups, which was due to an increase in the mRNA relative expression levels of the 5-HT receptor gene (5-HTR), neurotransmitter transporter genes (Drd4, Slc6a4), and neurotransmitter synthase tryptophan hydroxylase (TPH). Furthermore, GABA transaminase (GABA-T) activity increased in the 500 and 5000 µg/L groups, and tyrosine hydroxylase (TH) activity increased dramatically in the 5000 µg/L group. However, acetyl-CoA (AChE) activity was significantly reduced in these four BuP exposure groups. These changes could be attributed to decreased movement velocity and increased inactivity. Meanwhile, the mRNA expression level of BAX, Bcl-2, caspase-9 and TUNEL assay indicated the occurrence of cell apoptosis in the brains of the higher BuP exposed groups, which may play an important role in neuronal death inducing behavior change. In summary, these findings offer fundamental insights into turtle ecotoxicology and serve as a foundation for a comprehensive assessment of the ecological and health risks associated with BuP.

Butylparaben disordered intestinal homeostasis in Chinese striped-necked turtles (Mauremys sinensis)

Butylparaben (BuP) is regarded as a widespread pollutant, which has potential risk to aquatic organisms. Turtle species are an important part of aquatic ecosystems, however, the effect of BuP on aquatic turtles is not known. In this study, we evaluated the effect of BuP on intestinal homeostasis of Chinese striped-necked turtle (Mauremys sinensis). We exposed turtles to concentrations of BuP (0, 5, 50, and 500 μg/L) for 20 weeks, then investigated the composition of gut microbiota, the structure of intestine, and the inflammatory and immune status. We found BuP exposure significantly changed the composition of gut microbiota. Specially, the unique genus in three concentrations of BuP-treated groups mainly was Edwardsiella, which was not present in control group (0 μg/L of BuP). In addition, the height of intestinal villus was shortened, and the thickness of muscularis was thinned in BuP-exposed groups. Particularly, the number of goblet cells obviously decreased, the transcription of mucin2 and zonulae occluden-1 (ZO-1) significantly downregulated in BuP-exposed turtles. Meanwhile, neutrophils and natural killer cells in lamina propria of intestinal mucosa increased in BuP-treated groups, especially in high concentration of BuP (500 μg/L). Moreover, the mRNA expression of pro-inflammatory cytokines, especially IL-1β showed a significant upregulation with BuP concentrations. Correlation analysis indicated the abundance of Edwardsiella was positively correlated with IL-1β and IFN-γ expression, whereas its abundance was negatively correlative with the number of goblet cells. Taken together, the present study demonstrated BuP exposure disordered intestinal homeostasis through inducing dysbiosis of gut microbiota, causing inflammatory response and impairing gut physical barrier in turtles, which emphasized the hazard of BuP to health of aquatic organism.

Non-targeted proteomics reveals altered immune response in geographically distinct populations of green sea turtles (Chelonia mydas)

All seven species of sea turtle are facing increasing pressures from human activities that are impacting their health. Changes in circulating blood proteins of an individual, or all members of a population, can provide an early indicator of adverse health outcomes. Non-targeted measurement of all detectable proteins in a blood sample can indicate physiological changes. In the context of wildlife toxicology, this technique can provide a powerful tool for discovering biomarkers of chemical exposure and effect. This study presents a non-targeted examination of the protein abundance in sea turtle plasma obtained from three geographically distinct foraging populations of green turtles (Chelonia mydas) on the Queensland coast. Relative changes in protein expression between sites were compared, and potential markers of contaminant exposure were investigated. Blood plasma protein profiles were distinct between populations, with 85 out of the 116 identified proteins differentially expressed (p < 0.001). The most strongly dysregulated proteins were predominantly acute phase proteins, suggestive of differing immune status between the populations. The highest upregulation of known markers of immunotoxicity, such as pentraxin fusion and complement factor h, was observed in the Moreton Bay turtles. Forty-five different organohalogens were also measured in green turtle plasma samples as exposure to some organohalogens (e.g., polychlorinated biphenyls) has previously been identified as a cause for immune dysregulation in marine animals. The few detected organohalogens were at very low (pg/mL) concentrations in turtles from all sites, and are unlikely to be the cause of the proteome differences observed. However, the changes in protein expression may be indicative of exposure to other chemicals or environmental stressors. The results of this study provide important information about differences in protein expression between different populations of turtles, and guide future toxicological and health studies on east-Australian green sea turtles.

Toxicity of polychlorinated biphenyls in aquatic environments - A review

The assessment of polychlorinated biphenyls (PCBs) and their congeners resulting from the pollution of all environmental media is inherently related to its persistence and ubiquitous nature. In principle, determination of this class of contaminants are limited to the determination of their concentrations in the various environmental matrices. For solving many problems in this context, knowledge of the emission sources of PCBs, transport pathways, and sites of contamination and biomagnification is of great benefit to scientists and researchers, as well as many regulatory organizations. By far the largest amounts of PCBs, regardless of their discharged points, end up in the soil, sediment and finally in different aquatic environments. By reviewing relevant published materials, the source of origin of PCBs in the environment particularly from different pollution point sources, it is possible to obtain useful information on the nature of different materials that are sources of PCBs, or their concentrations and their toxicity or health effects and how they can be removed from contaminated media. This review focuses on the sources of PCBs in aquatic environments and critically reviews the toxicity of PCBs in aquatic animals and plants. The review also assesses the toxicity equivalency factors (TEFs) of PCBs providing valuable knowledge to other scientists and researchers that enables regulatory laws to be formulated based on selective determination of concentrations regarding their maximum permissible limits (MPLs) allowed. This review also supplies a pool of valuable information useful for designing decontamination technologies for PCBs in media like soil, sediment, and wastewaters.

Effects of salinization on the occurrence of a long-lived vertebrate in a desert river

The lower Pecos River located in the southwest USA, is a naturally saline river system that has been significantly altered in relatively recent years. Climate change, coupled with anthropogenic disturbances such as dam construction have led to portions of the river becoming more susceptible to increased salinization and declines in water quality. These alterations have been documented to be detrimental to multiple freshwater communities; however, there is a lack of knowledge on how these alterations influence long-lived species in the river, such as freshwater turtles, where the effects can appear over dramatically different temporal scales. The Rio Grande Cooter (Pseudemys gorzugi) is a species of concern known to occur in the Pecos River. To understand the current distribution and habitat requirements for P. gorzugi in the Pecos River, we used a single-season, single-species occupancy modeling framework to estimate occurrence while accounting for the sampling process. Day of year, water surface area, and water visibility had the greatest influence on the ability to detect the species given a sampling unit is occupied. Conductivity (a measure of salinity) had the greatest influence on the occupancy probability for the species, where sites with higher conductivity coincided with lower occupancy probabilities. This study indicates that increased salinization on the lower Pecos River is a cause for concern regarding freshwater turtle populations within the Chihuahuan Desert.

Toxic effects of ammonia on intestinal health and microbiota in red-eared slider (Trachemys scripta elegans)

Ammonia is an important environmental pollutant and can induce serious damages to the organs of aquatic animals, especially the intestine which is mostly exposed to external environment. As important species of aquatic ecosystems, turtles may be potential risk targets of ammonia. However, it is not clear whether ammonia shows toxic effects on the intestines of turtles. Therefore, the worldwide species red-eared slider (Trachemys scripta elegans) was selected, to investigate the effects of ammonia on intestinal health and the composition of microbiota. Results showed that ammonia significantly changed the structure of intestines by decreasing the thickness of intestinal wall, shortening the length of intestinal villus, extending lamina proprias, and inducing inflammatory cells appearance when the turtles were exposed to ammonia (1.418 mg NH₃ L^-1) for 30 d. In addition, the downregulation of epithelial tight junction genes indicated that ammonia increased selective paracellular permeability. Simultaneously, the upregulation of cytokines suggested that ammonia induced intestinal immune and inflammatory responses. Furthermore, ammonia altered the dominant bacterial composition, and decreased the abundance of beneficial intestinal bacteria in the host. Our results demonstrated that ammonia impaired the intestinal health and changed the composition of residential microbiota in T. s. elegans. This study provides a new insight to evaluate the toxic effects of ammonia on aquatic turtles and helps to build a framework for the effective conservation of turtles.

EVALUATION OF IMMUNE FUNCTION IN TWO POPULATIONS OF GREEN SEA TURTLES (CHELONIA MYDAS) IN A DEGRADED VERSUS A NONDEGRADED HABITAT

There is a strong correlation between degraded marine habitats and the prevalence of diseases such as green turtle fibropapillomatosis (GTFP) in coastal populations. In GTFP, small to large tumors grow on the turtle's soft tissues and shell, while internal nodules may also occur. The disease primarily affects juvenile green sea turtles (Chelonia mydas) that reside in nearshore waters. As a link has been shown between environmental pollution and immune suppression in a variety of animals, the objective of our research was to compare innate and adaptive immune responsiveness in green sea turtles from a severely degraded and a more pristine habitat, which differ greatly in rates of GTFP. We quantified phagocytosis by flow cytometry and performed in vitro stimulation analysis to measure activity of both the innate and adaptive immune systems in wild-caught Florida green turtles. Sea turtles from the degraded environment, both with and without visible cutaneous tumors, exhibited significantly reduced phagocytosis and stimulation indices than did those from the less polluted environment. Our results suggest that environmental factors may contribute to the development of GTFP and thus can impact the health of sea turtle populations.

Turtles and Tortoises Are in Trouble

Turtles and tortoises (chelonians) have been integral components of global ecosystems for about 220 million years and have played important roles in human culture for at least 400,000 years. The chelonian shell is a remarkable evolutionary adaptation, facilitating success in terrestrial, freshwater and marine ecosystems. Today, more than half of the 360 living species and 482 total taxa (species and subspecies combined) are threatened with extinction. This places chelonians among the groups with the highest extinction risk of any sizeable vertebrate group. Turtle populations are declining rapidly due to habitat loss, consumption by humans for food and traditional medicines and collection for the international pet trade. Many taxa could become extinct in this century. Here, we examine survival threats to turtles and tortoises and discuss the interventions that will be needed to prevent widespread extinction in this group in coming decades.

Determinants of Legacy Persistent Organic Pollutant Levels in the European Pond Turtle (Emys orbicularis) in the Camargue Wetland, France

Many banned persistent organic pollutants (POPs) remain for decades in the aquatic environment and can have harmful effects on long-lived predators because of their high bioaccumulation and biomagnification potentials. We investigated the occurrence and levels of 18 polychlorinated biphenyls (PCBs) and 16 organochlorine pesticides in European pond turtles (n = 174) from April to July 2018 in the Camargue wetland, France. Although the Camargue was highly contaminated in previous decades, plasma occurrence and levels of POPs were very low: we were able to quantify only 3 of the 34 compounds we analyzed in >10% of the turtles. The burdens from POPs did not differ between males and females and were uncorrelated with sampling date and body mass. We observed differences in POP burdens between turtles from the 2 sampling sites. One possible explanation is that the sampling sites were in different agricultural hydraulic systems: plasma occurrence and levels were higher for PCB-52 and hexachlorobenzene in turtles captured in drainage channels and for PCB-153 at the site that receives irrigation. Finally, the occurrence and levels of PCB-153 in turtles increased with age, likely because of bioaccumulation and much higher exposure 20 to 30 yr ago than now. Environ Toxicol Chem 2021;40:2261-2268. © 2021 SETAC.

The release of contaminants from steel slags and natural aggregates: Evaluation of toxicity and genotoxicity

Steel slags (SS) are the major waste produced by iron and steel industry. Slags may be reused as recycled materials, instead of natural aggregates (NA), to reduce the final disposal in a landfill and the exploitation of raw materials. However, the reuse of SS may generate a potential release of toxic compounds for the environment and humans. The purpose of this study was to evaluate the toxicity and genotoxicity of SS, in comparison with NA, by using an integrated chemical-biological approach to enable their safe reuse in engineering applications. Leaching solutions from samples were obtained by using short-term leaching tests (CEN EN 12457-2, 2004) usually adopted for the evaluation of waste recovery and final disposal. Chemical analyses of leachates were performed according to the Italian legislation on waste recovery (Ministerial Decree 186/2006). The leaching solutions were assayed by using toxicity test on Daphnia magna. Moreover, mutagenicity/genotoxicity tests on Salmonella typhimurium, Allium cepa, and human leucocytes and fibroblasts were carried out. The releases of pollutants from all samples were within the limits of the Italian legislation for waste recovery. Despite the effects that SS and NA could have on different cells, in terms of toxicity and genotoxicity, globally, SS do not seem to be any more hazardous than NA. This ecotoxicological assessment, never studied before, is important for promoting further studies that may support the decision-making process regarding the use of such types of materials.

Bioaccumulation and physiological responses of the turtle Chelydra serpentina exposed to polychlorinated biphenyls during early life stages

Despite the North American production ban of polychlorinated biphenyls (PCBs), PCBs are ubiquitous in the environment and in wildlife tissues. Chelydra serpentina serpentina (common snapping turtle) have been used as environmental indicators of PCB pollution upwards of 40 years given their high site fidelity and high trophic position. Despite their long use as indicators of PCB contamination, the effects of PCBs in reptiles remain largely unknown. In this study, we performed two experiments to assess i) bioaccumulation and ii) toxicity of PCBs to 1-month-old C. s. serpentina, to aid in interpretation of PCB burdens. Food pellets were spiked at an environmentally relevant concentration (0.45 μg/g) of the PCB mixture Aroclor 1254 to model hepatic bioaccumulation and depuration, through feeding, for 31 days and clean food for 50 days, respectively. No significant differences in PCB concentrations were observed in liver tissue over the course of the experiment, suggesting that juvenile turtles can likely metabolize low environmentally occurring concentrations of PCBs. Additionally, a dose-response experiment, performed to determine hepatic toxicity and bioaccumulation in juvenile C. s. serpentina, showed a 1.8-fold increase in hepatic expression of cyp1a when fed A1254-spiked pellets (12.7 μg/g; range 0-12.7 μg/g). This gene induction correlates with the significant increase of group 3 PCB congeners measured in the turtle liver, which are known to be metabolized by CYP1A. This study indicates that C. s. serpentina may be a good environmental indicator for PCBs, while more research is needed to assess the effects of body burdens in wild C. s. serpentina.

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.

Halogenated organic compounds in the eggs of aquatic birds from the Gulf of Gdansk and Wloclawek Dam (Poland)

Diet is the major route of exposure to environmental contaminants in biota and, after penetration into an organism, xenobiotics continue to accumulate in the body. In birds the egg-laying process acts as a transfer mechanism for the accumulated pollutants and results in the burdening of the next generation at an early stage of development. This transfer has a strong influence on developmental disorders and even breeding success. With this in mind polybrominated diphenyl ethers (PBDE), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo furans (PCDD/Fs), as well as polychlorinated biphenyls (PCBs), were analyzed in the eggs of aquatic birds from different habitats and with different diet preferences. The highest concentration of PBDE was noted in gull eggs (198.31 ng g^-1 dw.) and the lowest in tern eggs (sandwich tern: 76.96 ng g^-1 dw.; common tern: 113.73 ng g^-1 dw). Deca-BDE was detected only in herring gull eggs from the Wloclawek reservoir. PCDDF/s were found in the eggs of terns from the southern coast of the Baltic Sea and gulls from an inland reservoir (dam) on the River Vistula close to the town of Wloclawek. The highest toxicity (birds Toxic Equivalent Factor) was found in the eggs of terns (sandwich tern - 93.97 pg g^-1 dw., common tern - 68.35 pg g^-1 dw.), and this was found to be several times higher than in herring gull eggs (18.80 pg g^-1 dw.). Non-dioxin like PCBs were ten times higher than other analyzed PCB congeners, but the congener pattern was similar to other studies.

Lactational exposure to dioxin-like polychlorinated biphenyl 169 and nondioxin-like polychlorinated biphenyl 155: Effects on rat femur growth, biomechanics and mineral composition

Exposure to polychlorinated biphenyls (PCBs), which are persistent lipophilic environmental pollutants, has a variety of adverse effects on wildlife and human health, including bone mineralization, growth and mechanical strength. The present study evaluated the effects of lactational exposure to nondioxin-like PCB-155 and dioxin-like PCB-169, individually and in combination, on pubertal rat femur development and its biomechanics. After offspring delivery, Wistar rat mothers were divided into four groups, i.e., PCB-169, PCB-155, PCB-155+169 and control, and were administered PCBs intraperitoneally. Data on bone geometry, biomechanics and mineral composition were obtained by analysis of femurs from 42-day-old offspring by microCT scanning, three-point bending test and inductively coupled plasma mass spectrometry. Decreased somatic mass and femur size, i.e., mass, periosteal circumference and cross sectional area, were observed in the PCB-169 and PCB-155 groups. Additionally, lactational exposure to planar PCB-169 resulted in harder and more brittle bones containing higher amounts of minerals. Combined exposure to structurally and functionally different PCBs demonstrated only mild alterations in bone width and mineralization. To conclude, our results demonstrated that alterations, observed on postnatal day 42, were primarily induced by PCB-169, while toxicity from both of the individual congeners may have been reduced in the combined group.

Morphological and physiological assessments reveal that freshwater turtle (Mauremys leprosa) can flourish under extremely degraded-polluted conditions

Freshwater turtles are long-lived sedentary organisms used as biological sentinels to assess anthropogenic perturbations in freshwater-ecosystems; notably because pollutants tend to accumulate in their tissues. Pollution has detrimental effects in sea turtles, but studies in freshwater turtles have provided contrasted results: several species have been impacted by habitat perturbation and pollution while others not. It is important to explore this issue since freshwater turtles are threatened worldwide. We compared two populations of the stripe necked terrapin (Mauremys leprosa) in a relatively pristine area (piedmont of the Atlas mountain) versus an extremely degraded-polluted area (sewers of a large city) in Morocco. All morphological and physiological proxies showed that turtles were able to cope remarkably well with highly degraded-polluted habitat. Population density, body size, and body condition were higher in the sewers, likely due to permanent water and food availability associated with human wastes. Stress markers (e.g. glucocorticoids) provided complex results likely reflecting the capacity of turtles to respond to various stressors. Reproductive parameters (testosterone level, indices of vitellogenesis) were lower in the relatively pristine area. The deceptive overall image provided by these analyses may hide the disastrous human impact on rivers. Indeed, Mauremys leprosa is the only aquatic vertebrate able to survive in the sewers, and thus, might nonetheless be a pertinent indicator of water quality, providing that the complexity of eco-physiological responses is considered.

Geographic variation in thermal sensitivity of early life traits in a widespread reptile

Taxa with large geographic distributions generally encompass diverse macroclimatic conditions, potentially requiring local adaptation and/or phenotypic plasticity to match their phenotypes to differing environments. These eco-evolutionary processes are of particular interest in organisms with traits that are directly affected by temperature, such as embryonic development in oviparous ectotherms. Here we examine the spatial distribution of fitness-related early life phenotypes across the range of a widespread vertebrate, the painted turtle (Chrysemys picta). We quantified embryonic and hatchling traits from seven locations (in Idaho, Minnesota, Oregon, Illinois, Nebraska, Kansas, and New Mexico) after incubating eggs under constant conditions across a series of environmentally relevant temperatures. Thermal reaction norms for incubation duration and hatchling mass varied among locations under this common-garden experiment, indicating genetic differentiation or pre-ovulatory maternal effects. However, latitude, a commonly used proxy for geographic variation, was not a strong predictor of these geographic differences. Our findings suggest that this macroclimatic proxy may be an unreliable surrogate for microclimatic conditions experienced locally in nests. Instead, complex interactions between abiotic and biotic factors likely drive among-population phenotypic variation in this system. Understanding spatial variation in key life-history traits provides an important perspective on adaptation to contemporary and future climatic conditions.

Determination of real-world emission factors of trace metals, EC, OC, BTEX, and semivolatile organic compounds (PAHs, PCBs and PCNs) in a rural tunnel in Bilecik, Turkey

A field study was performed in a rural tunnel to determine pollutant concentrations, sources and on road vehicle emission factors (EFs) of particulate matter, trace metals, elemental carbon (EC), organic carbon (OC), benzene, toluene, ethyl benzene and xylenes (BTEX), and polycyclic aromatic hydrocarbons (PAHs). Emission factors (EFs) for polychlorinated naphthalenes (PCNs) and polychlorinated biphenyls (PCBs) were also determined. A 12-day extensive sampling campaign during morning and afternoon periods at inlet and exit stations of the tunnel was conducted. Morphology of the particles was also investigated by Scanning Electron Microcopy (SEM). Correlation analysis, factor analysis and diagnostic PAH ratios were utilized to identify emission sources of trace metals. Identified sources include brake wear (33%), resuspension of road dust (15%), tyre wear (12%), exhaust emissions (10%), and lubricants (9%). Based on the PAH diagnostic ratios, major sources of PAHs were estimated as diesel emissions. EFs were comparable with the literature and varied from 31.5 to 295.4 mg vehicle^-1 km^-1 with an average of 129.2 ± 80 mg vehicle^-1 km^-1 for PM_2.5. PM_2.5-10 EFs varied between 15.9 and 236.1 mg vehicle^-1 km^-1 with an average of 96 ± 30 mg vehicle^-1 km^-1. Average EC EFs were 40.3 ± 9.8 mg vehicle^-1 km^-1 for PM_2.5 samples and 19.5 ± 0.5 mg vehicle^-1 km^-1 for PM_2.5-10 samples while OC EFs were 33.7 ± 18 and 15.5 ± 8.4 mg vehicle^-1 km^-1 for fine and coarse particles, respectively. EFs of elements were generally 2 (Al) to 59 (Mg) times higher than those previously reported in the literature. Compared to literature, relatively higher EFs for Σ₁₃PAHs (range: 48.1-168 μg vehicle^-1 km^-1, average: 84.3 ± 46.4 μg vehicle^-1 km^-1) were obtained. BTEX emission factors were in the range of 4.2 ± 4.7 mg vehicle^-1 km^-1 (m + p-xylene) and 16.7 ± 10.5 mg vehicle^-1 km^-1 (toluene). Average EFs for ΣPCBs and ΣPCNs were 12.06 ± 5.3 μg vehicle^-1 km^-1 and 88.9 ± 70.4 ng vehicle^-1 km^-1, respectively.

Transformer oils as a potential source of environmental exposure to polychlorinated biphenyls (PCBs): an assessment in three central provinces of Iran

Polychlorinated biphenyl (PCB) contamination of oils from all transformers of the national electrical grid in Tehran, Qom, and Alborz, three central provinces of Iran, was assessed. The concentration of PCBs in transformer oils was determined by gas chromatography. At the national level, the proportions of transformers with oil PCB contents of <5, 5-49, 50-499, 500-4999, and >5000 ppm were determined to be 85.7, 12.4, 1.6, 0.1, and 0.1%, respectively. About 0.5% of transformer oils (66,000 kg out of 13,342,000 kg) exhibited PCB levels higher than 50 ppm that based on the Stockholm Convention should be phased out before 2025. The contaminated oils contained 91.4% of detected PCBs (132 kg PCBs out of 144 kg PCBs) and were located in 1.9% of transformers (27 transformers out of 1449 transformers). Statistical analysis indicated that the year of manufacture and manufacturing company provided significant effects on PCB contamination (p value <0.001). PCB contamination of transformer oils in Tehran was higher than that of the other provinces that could be mainly caused by the older average year of manufacture. PCB levels higher than 499 ppm were also observed only in Tehran. This study provided valuable information for future studies on identification of PCB-contaminated transformers as well as planning and design of waste management facilities for PCB-contaminated oils at the national level.

Development and validation of a subcritical 1,1,1,2-tetrafluoroethane extraction technique: Gas chromatography-mass spectrometry method for the simultaneous determination of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and polybrominated biphenyl ethers in aquatic products

A simple, rapid, and green method was developed for the simultaneous analysis of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and polybrominated biphenyl ethers in aquatic products using subcritical 1,1,1,2-tetrafluoroethane extraction coupled with gas chromatography and mass spectrometry. Effects of the extraction temperature, pressure, and cosolvent volume on the extraction efficiency were investigated by extracting spiked oyster samples. The results show that the maximum extraction efficiency was obtained at 40°C, 12 MPa, and a cosolvent (dichloromethane) volume of 5.0 mL. Under these conditions, the calibration curves had good linearity with square of the correlation larger than 0.998 in the concentration range of 5-800 ng/mL; limit of detection and limit of quantitation were 0.16-2.83 and 0.55-9.43 ng/g, respectively. At spiked levels of 10, 30, and 50 ng/g, the average recoveries were 70.4-80.4% for polycyclic aromatic hydrocarbons, 74.0-83.6% for polychlorinated biphenyls, and 66.9-78.0% for polybrominated biphenyl ethers, with average relative standard deviations of less than 16.3%. The established method has no significant differences in recovery compared to traditional methods and is suitable for the analysis of real samples.

Effects of structurally different noncoplanar and coplanar PCBs on HELF cell proliferation, cell cycle, and potential molecular mechanisms

Polychlorinated biphenyls (PCBs) are a group of chemicals that persist in the environment, indoors, and humans. Lung exposure to airborne and food contaminants, such as PCBs, may cause possible lung disorders, such as cancer. In the present study, we investigated the effects of structurally different lower chlorinated (≤4Cl), noncoplanar PCB40, and coplanar PCB77 on human lung fibroblast cell line (HELF) cell proliferation, cell cycle progression, and possible molecular mechanisms. Noncoplanar PCB40 and coplanar PCB77 exhibited concentration- and time-dependent biphasic dose-response effects on HELF cell proliferation. Noncoplanar PCB40 and coplanar PCB77 induced 23 and 45% cytotoxicity at higher concentrations than the control. The flow cytometry analysis showed that exposure to PCB40 caused a significant increase in time spent in the G1 phase but decreased length of the S phase in a concentration- and time-dependent manner, whereas PCB77 exposure decreased time spent in the G1 and S phases but increased time spent in the G2 phase. Western blot analysis indicated that PCB77 increased the expression of cyclin E, CDK2, p21, and caspase-9, while PCB40 decreased the expression of these proteins (except CDK2 and p21). An increase in CDK expression after exposure to PCB77 suggests that it may cause carcinogenic effects on HELF cells at higher doses. Our results also demonstrate that the different cytotoxic effects induced by coplanar and nonplanar PCBs were correlated with their structural characteristics; the coplanar congener was more cytotoxic than the nonplanar congener. The study elaborates threshold levels for these chemicals and suggests that the cytotoxicity mechanisms by which PCB congeners act on HELF cells depend on their planarity and chemical structures. Furthermore, the study will be important for developing antidotes to the adverse effects and risk assessment practices for PCBs. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1183-1190, 2017.

Statistical Survey of Persistent Organic Pollutants: Risk Estimations to Humans and Wildlife through Consumption of Fish from U.S. Rivers

U.S. EPA conducted a national statistical survey of fish tissue contamination at 540 river sites (representing 82 954 river km) in 2008-2009, and analyzed samples for 50 persistent organic pollutants (POPs), including 21 PCB congeners, 8 PBDE congeners, and 21 organochlorine pesticides. The survey results were used to provide national estimates of contamination for these POPs. PCBs were the most abundant, being measured in 93.5% of samples. Summed concentrations of the 21 PCB congeners had a national weighted mean of 32.7 μg/kg and a maximum concentration of 857 μg/kg, and exceeded the human health cancer screening value of 12 μg/kg in 48% of the national sampled population of river km, and in 70% of the urban sampled population. PBDEs (92.0%), chlordane (88.5%) and DDT (98.7%) were also detected frequently, although at lower concentrations. Results were examined by subpopulations of rivers, including urban or nonurban and three defined ecoregions. PCBs, PBDEs, and DDT occur at significantly higher concentrations in fish from urban rivers versus nonurban; however, the distribution varied more among the ecoregions. Wildlife screening values previously published for bird and mammalian species were converted from whole fish to fillet screening values, and used to estimate risk for wildlife through fish consumption.