Levels of perfluorinated acids (PFCAs) in different tissues of Lepidochelys olivacea sea turtles from the Escobilla beach (Oaxaca, Mexico)

Skin sampling as a proxy for screening per- and polyfluoroalkyl substances (PFAS) exposures in endangered sea turtles

Per- and polyfluoroalkyl substances (PFAS) are widespread in the environment, including the ocean. However, information on PFAS exposures in protected and endangered sea turtle species is scarce because sampling liver or blood is invasive and challenging. We assessed, for the first time, whether skin tissue, which is less invasive to collect, can be used to screen for PFAS in sea turtles. We measured concentrations of 20 PFAS in the skin and serum from deceased juvenile green turtles. Perfluorooctane sulfonic acid (PFOS) was the predominant PFAS and was detected in most of the skin (85 %) and serum (100 %). For individuals with paired skin and serum, PFOS concentrations were not significantly different, and thus suggest that skin samples have promising use for screening PFAS in sea turtles. This method may be adapted and optimized in the future to increase data coverage and improve our understanding of sea turtle exposures to PFAS.

First insights into aliphatic and polycyclic aromatic hydrocarbons (PAHs) in hawksbill turtle (Eretmochelys imbricata) eggs from Persian Gulf, Iran

Petroleum pollution in marine ecosystems has raised great concern for both marine organisms and human health. The Persian Gulf, as a significant hotspot of petroleum pollution, is a crucial nesting area for hawksbill turtles (Eretmochelys imbricata) worldwide. In this work concentration level, source, and compositional profiles of polycyclic aromatic hydrocarbons (PAHs) and normal alkanes (n-alkanes) were analyzed in the yolk, albumen, and shell of hawksbill turtle eggs collected from 3 nests on the Persian Gulf coast of Iran. Twenty-eight PAHs and 19 n-alkanes were detected in samples. The highest levels of ƩPAHs and Ʃn-alkanes were found in yolk samples compared to the albumen and shell, possibly due to the high lipid content and lengthy duration of yolk formation. Comparable levels of pollutants were found in eggshells, indicating the potential for turtle eggshells to accumulate organic pollutants. The source of PAHs and n-alkanes in all samples primarily indicates petrogenic, suggesting extensive oil-producing activities and petroleum pollution in the Persian Gulf. Inter-nest variations in levels and profiles of PAHs and n-alkanes were observed in the eggs from the 3 nests, which might be related to the turtle's diets and migration patterns. Although this study provides the first monitoring data on organic pollutants for sea turtles in the Persian Gulf, more complementary researches are required in terms of monitoring petroleum biomarkers in foraging grounds, maternal blood, and their eggs in this region.

Poly- and perfluoroalkyl substances (PFASs) in amphibians and reptiles - exposure and health effects

Poly- and perfluoroalkyl substances (PFASs) are commonly used in various industries and everyday products, including clothing, electronics, furniture, paints, and many others. PFASs are primarily found in aquatic environments, but also present in soil, air and plants, making them one of the most important and dangerous pollutants of the natural environment. PFASs bioaccumulate in living organisms and are especially dangerous to aquatic and semi-aquatic animals. As endocrine disruptors, PFASs affect many internal organs and systems, including reproductive, endocrine, nervous, cardiovascular, and immune systems. This manuscript represents the first comprehensive review exclusively focusing on PFASs in amphibians and reptiles. Both groups of animals are highly vulnerable to PFASs in the natural habitats. Amphibians and reptiles, renowned for their sensitivity to environmental changes, are often used as crucial bioindicators to monitor ecosystem health and environmental pollution levels. Furthermore, the decline in amphibian and reptile populations worldwide may be related to increasing environmental pollution. Therefore, studies investigating the exposure of amphibians and reptiles to PFASs, as well as their impacts on these organisms are essential in modern toxicology. Summarizing the current knowledge on PFASs in amphibians and reptiles in a single manuscript will facilitate the exploration of new research topics in this field. Such a comprehensive review will aid researchers in understanding the implications of PFASs exposure on amphibians and reptiles, guiding future investigations to mitigate their adverse effects of these vital components of ecosystems.

Perfluorinated Carboxylic Acids with Increasing Carbon Chain Lengths Upregulate Amino Acid Transporters and Modulate Compensatory Response of Xenobiotic Transporters in HepaRG Cells

Perfluorinated carboxylic acids (PFCAs) are widespread environmental pollutants for which human exposure has been documented. PFCAs at high doses are known to regulate xenobiotic transporters partly through peroxisome proliferator-activated receptor alpha (PPARα) and constitutive androstane receptor (CAR) in rodent models. Less is known regarding how various PFCAs at a lower concentration modulate transporters for endogenous substrates, such as amino acids in human hepatocytes. Such studies are of particular importance because amino acids are involved in chemical detoxification, and their transport system may serve as a promising therapeutic target for structurally similar xenobiotics. The focus of this study was to further elucidate how PFCAs modulate transporters involved in intermediary metabolism and xenobiotic biotransformation. We tested the hepatic transcriptomic response of HepaRG cells exposed to 45 μM of perfluorooctanoic acid, perfluorononanoic acid, or perfluorodecanoic acid in triplicates for 24 hours (vehicle: 0.1% DMSO), as well as the prototypical ligands for PPARα (WY-14643, 45 μM) and CAR (6-(4-chlorophenyl)imidazo[2,1-b][1,3]thiazole-5-carbaldehyde O-(3,4-dichlorobenzyl)oxime [CITCO], 2 μM). PFCAs with increasing carbon chain lengths (C8-C10) regulated more liver genes, with amino acid metabolism and transport ranked among the top enriched pathways and PFDA ranked as the most potent PFCA tested. Genes encoding amino acid transporters, which are essential for protein synthesis, were novel inducible targets by all three PFCAs, suggesting a potentially protective mechanism to reduce further toxic insults. None of the transporter regulations appeared to be through PPARα or CAR but potential involvement of nuclear factor erythroid 2-related factor 2 is noted for all 3 PFCAs. In conclusion, PFCAs with increasing carbon chain lengths up-regulate amino acid transporters and modulate xenobiotic transporters to limit further toxic exposures in HepaRG cells. SIGNIFICANCE STATEMENT: Little is known regarding how various perfluorinated carboxylic acids modulate the transporters for endogenous substrates in human liver cells. Using HepaRG cells, this study is among the first to show that perfluorinated carboxylic acids with increasing carbon chain lengths upregulate amino acid transporters, which are essential for protein synthesis, and modulate xenobiotic transporters to limit further toxic exposures at concentrations lower than what was used in the literature.

Within-season shifts in multiple paternity patterns in mass-nesting olive ridley sea turtles

Multiple paternity is common to all sea turtle species, but its causes and consequences are hard to ascertain and the behaviors and success of males difficult to observe. This study aims to describe patterns of multiple paternity for olive ridley turtles Lepidochelys olivacea at Playa de Escobilla, an ‘arribada’ (mass-nesting) site on the Mexican Pacific coast with over a million clutches laid each reproductive season. A total of 15 females and their hatchlings were sampled during 3 arribada events which occurred over the 2016-2017 nesting season. Females and hatchlings (N = 329) were genotyped at 5 microsatellite loci, from which we inferred the alleles of 46 contributing males. Multiple paternity was detected in 60% of the analyzed clutches, which were sired by a range of 2 to 7 males. Multiple paternity rates differed significantly across arribada events, suggesting more males achieved fertilizations earlier in the breeding season. Paternal contribution in 6 of the clutches with multiple paternity was skewed towards a single male; the remaining clutches had a homogeneous male contribution. However, our results are based on relatively small within-arribada sample sizes. The frequency of multiple paternity among turtle clutches laid on this arribada beach could be related to the density of breeding individuals in the reproductive patch off Playa de Escobilla, rather than to the nesting population size or female size.

Internal and Maternal Distribution of Persistent Organic Pollutants in Sea Turtle Tissues: A Meta-Analysis

We aimed to identify patterns in the internal distribution of persistent organic pollutants (POPs) and assess contributing factors using sea turtles and their offspring as a case study of a long-lived wildlife species. We systematically synthesized 40 years of data and developed a lipid database to test whether lipid-normalized POP concentrations are equal among tissues as expected under steady state for lipophilic compounds. Results supported equal partitioning among tissues with high blood flow or perfusion including the heart, kidney, muscle, and lung. Observed differences in the brain, fat, and blood plasma, however, suggest the physiological influence of the blood-brain barrier, limited perfusion, and protein content, respectively. Polybrominated diphenyl ethers partitioned comparably to legacy POPs. Polycyclic aromatic hydrocarbons, meanwhile, partitioned more into the lung, colon, and muscle compared to the liver under chronic and acute field exposure. Partitioning ratios of individual POPs among tissues were significantly related to the lipophilicity of compounds (as estimated by K_ow) in half of the observed cases, and significant differences between juveniles and adults underscore physiological differences across life stages. The comprehensive tissue partitioning patterns presented here provide a quantitative basis to support comparative assessments of POP pollution derived from biomonitoring among multiple tissues.

Sea turtles across the North Pacific are exposed to perfluoroalkyl substances

Perfluorinated alkyl substances (PFASs) are global, persistent, and toxic contaminants. We assessed PFAS concentrations in green (Chelonia mydas) and hawksbill (Eretmochelys imbricata) turtles from the North Pacific. Fifteen compounds were quantified via liquid chromatography tandem mass spectrometry from 62 green turtle and 6 hawksbill plasma samples from Hawai'i, Palmyra Atoll, and the Northern Marianas Islands. Plasma from 14 green turtles severely afflicted with fibropapillomatosis, and eggs from 12 Hawaiian hawksbill nests from 7 females were analyzed. Perfluorooctane sulfonate (PFOS) predominated in green turtle plasma; perfluorononanoic acid (PFNA) predominated in hawksbill tissues. Concentrations were greater in hawksbill than green turtle plasma (p < 0.05), related to trophic differences. Green turtle plasma PFOS concentrations were related to human populations from highest to lowest: Hawai'i, Marianas, Palmyra. Influence on fibropapillomatosis was not evident. PFASs were maternally transferred to hawksbill eggs, with decreasing concentrations with distance from airports and with clutch order from one female. A risk assessment of PFOS showed concern for immunosuppression in Kailua green turtles and alarming concern for hawksbill developmental toxicity. Perfluoroundecanoic (PFUnA) and perfluorotridecanoic (PFTriA) acid levels were correlated with reduced emergence success (p < 0.05). Studies to further examine PFAS effects on sea turtle development would be beneficial.

Legacy and Emerging Per- and Polyfluoroalkyl Substances: Analytical Techniques, Environmental Fate, and Health Effects

Due to their unique chemical properties, per- and polyfluoroalkyl substances (PFAS) have been used extensively as industrial surfactants and processing aids. While several types of PFAS have been voluntarily phased out by their manufacturers, these chemicals continue to be of ecological and public health concern due to their persistence in the environment and their presence in living organisms. Moreover, while the compounds referred to as “legacy” PFAS remain in the environment, alternative compounds have emerged as replacements for their legacy predecessors and are now detected in numerous matrices. In this review, we discuss the historical uses of PFAS, recent advances in analytical techniques for analysis of these compounds, and the fate of PFAS in the environment. In addition, we evaluate current biomonitoring studies of human exposure to legacy and emerging PFAS and examine the associations of PFAS exposure with human health impacts, including cancer- and non-cancer-related outcomes. Special focus is given to short-chain perfluoroalkyl acids (PFAAs) and ether-substituted, polyfluoroalkyl alternatives including hexafluoropropylene oxide dimer acid (HFPO-DA; tradename GenX), 4,8-dioxa-3H-perfluorononanoic acid (DONA), and 6:2 chlorinated polyfluoroethersulfonic acid (6:2 Cl-PFESA; tradename F-53B).

Changes in global protein expression in sea turtle cells exposed to common contaminants indicates new biomarkers of chemical exposure

Non-targeted protein expression at the cellular level can provide insights into mechanistic effects of contaminants in wildlife, and hence new and potentially more accurate biomarkers of exposure and effect. However, this technique has been relatively unexplored in the realm of in vitro biomarker discovery in threatened wildlife, despite the vulnerability of this group of animals to adverse sublethal effects of contaminant exposure. Here we examined the usefulness of non-targeted protein expression for biomarker discovery in green sea turtles (Chelonia mydas) by investigating differences in the response of primary cells from five different tissue types that were exposed to three contaminants known to accumulate in this species. Cells derived from C. mydas skin, liver, kidney, ovary and small intestine were exposed to 100 μg/L of either polychlorinated biphenyl 153 (PCB153), perfluorononanoic acid (PFNA) or phenanthrene for 24 h. The global protein expression was then quantitatively evaluated using sequential window acquisition of all theoretical mass spectra (SWATH-MS). Comparison of the global protein profiles revealed that, while a majority of proteins were mutually expressed in controls of all tissue types (~90%), the response to exposure in terms of protein expression strength was significantly different between tissue types. Furthermore, a comparison to known markers of chemical exposure in sea turtles from the literature indicated that in vitro response can reflect known in vivo responses. In particular, markers such as heat shock protein (HSP) 60, glutathione S-transferases (GSTs) and superoxide dismutases (SODs), cytochrome P450 and catalase were dysregulated in response to exposure. Furthermore, potential new markers of exposure were discovered such as annexin, an important protein in cell signalling processes. While this methodology proved promising further studies are required to confirm the accuracy of in vitro protein expression as a tool for biomarker discovery in wildlife.

Persistent organic pollutants in Kemp's Ridley sea turtle Lepidochelys kempii in Playa Rancho Nuevo Sanctuary, Tamaulipas, Mexico

Persistent organic pollutants (POP) are toxic substances for wildlife and people. The Kemp's Ridley sea turtle Lepidochelys kempii is an endangered species with limited distribution in the Gulf of Mexico (GM), a marine ecosystem that has been perturbed by a variety of anthropogenic activities. In this work, the concentrations of ten organochlorine pesticides (OP), eight polychlorinated biphenyls (PCB), and atrazine were determined in the plasma of Kemp's Ridley sea turtles that nest in Playa Rancho Nuevo Sanctuary, Tamaulipas, Mexico. Seventy-nine blood samples were collected from female turtles during the 2015-2016 nesting season. Samples were extracted with a focalized ultrasonic sound technique and analyzed through Gas Chromatography coupled to a Mass Spectrometer. POP with the highest percentage of detection were atrazine > PCB 52 > PCB 153 > DDE > alpha endosulfan > DDD > alpha HCH > DDT. There is no linear correlation between the detected POP levels in the Kemp's Ridley sea turtle plasma and its curve carapace length (CCL). When comparing 2015 and 2016 POP concentrations, there were statistically significant differences in atrazine (p < 0.05, R² = 0.069), PCB 52 (p < 0.05, R² = 0.0051) and ∑POP (p < 0.05, R² = 0.0001) and, no statistically significant differences in alpha endosulfan (p < 0.05, R² = 0.0294), DDE (p < 0.05, R² = 0.0315) and PCB 153 (p < 0.05, R² = 0.0036). The reported POP values of this work are one of the few registered for Kemp's Ridley sea turtle in the GM and the first for atrazine levels. These levels were higher than those reported for other sea turtle species from America, Africa, and Europe, which demonstrates a deteriorated health status of the GM marine ecosystem.

Perfluoroalkyl substances in the Yangtze River: Changing exposure and its implications after operation of the Three Gorges Dam

Potential ecological risk from perfluoroalkyl substances (PFASs) under changing exposure in large river systems has become a new challenge recently. Based on systematic monitoring of PFASs at 43 hydrologic stations along a 4300 km continuum of the Yangtze River, we investigated the ecological risk of PFASs under changing exposure resulting from operation of the Three Gorges Dam (TGD). Importantly, perfluorooctanoic acid (PFOA) was found extensively exposed in most mainstream water samples, accounting for about 90% of the total content of PFASs in both spring and autumn, while short-chain PFASs contributed more than PFOA in sediment. The significant inversion of long-chain PFASs occurrence from sediment to water reflected a profound change in exposure due to loss of finer sediments resulting from long-distance and long-term scour of the riverbed downstream of the TGD. The coarsening of bed materials would weaken sorption of long-chain PFASs in sediments and enhance their exposure in water, resulting in substantial increase of ecological risk to representative aquatic organisms. In the long term, particular attention should be paid to reduction of PFOA discharge to downstream of the TGD from typical industries. This also highlights the significance of huge dams to alternative exposures of persistent organic pollutants and the necessity of new strategy for ecological risk management of large river systems.