Understanding PFAAs exposure in a generalist seabird species breeding in the vicinity of a fluorochemical plant: Influence of maternal transfer and diet

Maternal transfer of per- and polyfluoroalkyl substances (PFAS) in wild birds: A systematic review and meta-analysis

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals widely used in consumer products. PFAS can accumulate in animal tissues, resulting in biomagnification and adverse effects on wildlife, such as reproductive impairment. In bird species, PFAS are transferred from mothers to eggs along with essential nutrients and may affect embryo development. However, the extent of maternal PFAS transfer across different species and compounds remains poorly understood. Here, we conducted a systematic review and meta-analysis to quantify maternal PFAS transfer in wild birds and investigate potential sources of variation. We tested the moderating effects of compounds' physicochemical properties and biological traits of studied birds. The dataset included 505 measurements of PFAS concentration and 371 effect sizes derived from 13 studies on 16 bird species and 25 compounds. Overall, across all studies and species, we found a 41% higher concentration of PFAS in offspring than in mothers. Specifically, contaminants were concentrated in the yolk, longer and heavier compounds showed preferential transfer, larger clutch size was associated with decreased PFAS transfer and a higher transfer rate was shown in species with piscivorous and opportunistic/diverse diets. A validation assessment showed good robustness of the overall meta-analytic result. Given the crucial role of birds in maintaining ecological balance, this research article has relevant implications for modelling the impacts of PFAS on wildlife, ecosystems, and human health.

Extraordinary levels of per- and polyfluoroalkyl substances (PFAS) in vertebrate animals at a New Mexico desert oasis: Multiple pathways for wildlife and human exposure

Per- and polyfluoroalkyl substances (PFAS) in the environment pose persistent and complex threats to human and wildlife health. Around the world, PFAS point sources such as military bases expose thousands of populations of wildlife and game species, with potentially far-reaching implications for population and ecosystem health. But few studies shed light on the extent to which PFAS permeate food webs, particularly ecologically and taxonomically diverse communities of primary and secondary consumers. Here we conducted >2000 assays to measure tissue-concentrations of 17 PFAS in 23 species of mammals and migratory birds at Holloman Air Force Base (AFB), New Mexico, USA, where wastewater catchment lakes form biodiverse oases. PFAS concentrations were among the highest reported in animal tissues, and high levels have persisted for at least three decades. Twenty of 23 species sampled at Holloman AFB were heavily contaminated, representing middle trophic levels and wetland to desert microhabitats, implicating pathways for PFAS uptake: ingestion of surface water, sediments, and soil; foraging on aquatic invertebrates and plants; and preying upon birds or mammals. The hazardous long carbon-chain form, perfluorooctanosulfonic acid (PFOS), was most abundant, with liver concentrations averaging >10,000 ng/g wet weight (ww) in birds and mammals, respectively, and reaching as high 97,000 ng/g ww in a 1994 specimen. Perfluorohexanesulfonic acid (PFHxS) averaged thousands of ng/g ww in the livers of aquatic birds and littoral-zone house mice, but one order of magnitude lower in the livers of upland desert rodent species. Piscivores and upland desert songbirds were relatively uncontaminated. At control sites, PFAS levels were strikingly lower on average and different in composition. In sum, legacy PFAS at this desert oasis have permeated local aquatic and terrestrial food webs across decades, severely contaminating populations of resident and migrant animals, and exposing people via game meat consumption and outdoor recreation.

Physiological effects of PFAS exposure in seabird chicks: A multi-species study of thyroid hormone triiodothyronine, body condition and telomere length in South Western France

There is growing evidence that poly and perfluoroalkyl substances (PFAS) exposure leads to the disruption of thyroid hormones including thyroxine (T4) and triiodothyronine (T3), and may affect telomeres, repetitive nucleotide sequences which protect chromosome ends. Many seabird species are long-lived top predators thus exhibit high contaminant levels, and PFAS-disrupting effects on their physiology have been documented especially in relation to the endocrine system in adults. On the contrary, studies on the developmental period (i.e., chicks), during which exposure to environmental contaminants may have a greater impact on physiological traits, remain scarce to this date. We carried out a multi-species study with the aim to assess whether and to which extent chicks of four gull species (herring gull, great and lesser black-backed gull, yellow-legged gull) in South Western France are contaminated by PFAS, and to bring further evidence about their potential physiological consequences. Linear PFOS showed concentrations of concern as it was generally >10 times higher than the other PFAS, and exceeded a threshold toxicity level (calculated from previous studies in birds) in almost all sampled chicks. Nonetheless, in herring gull male chicks, total T3 levels were significantly and negatively associated with perfluorodecanoate (PFDA) and perfluorododecanoate (PFDoDA) and positively associated with perfluorotetradecanoate (PFTeDA) in female chicks. Total T3 levels were also positively associated with PFDoDA in great black backed gull male chicks and with perfluorotridecanoate (PFTrDA) in lesser black backed gull chicks. In lesser and great black-backed gulls, both females and males showed significant negative associations between several PFAS and their body condition, and a positive association between telomere length and L-PFOS in the yellow-legged gull was also found. These results corroborate previous findings and need to be further explored as they suggest that PFAS may interfere with the physiological status of chicks during the developmental period, potentially inducing long-lasting consequences.

Transcriptomic effects of Perfluoralkyl acids on the adipose tissue of a songbird species at environmentally relevant concentrations

Perfluoralkyl acids (PFAS) have been regarded as global pollutants for at least twenty years, with potentially negative physiological effects on multiple vertebrate species including humans. Here we analyze the effects of the administration of environmentally-relevant levels of PFAS on caged canaries (Serinus canaria) by using a combination of physiological, immunological, and transcriptomic analyses. This constitutes a completely new approach to understand the toxicity pathway of PFAS in birds. While we observed no effects on physiological and immunological parameters (e.g, body weight, fat index, cell-mediated immunity), the transcriptome of the pectoral fatty tissue showed changes compatible with the known effects of PFAS as obesogens in other vertebrates, particularly in mammals. First, transcripts related to the immunological response were affected (mainly enriched), including several key signaling pathways. Second, we found a repression of genes related to the peroxisome response and fatty acid metabolism. We interpret these results as indicative of the potential hazard of environmental concentrations of PFAS on the fat metabolism and the immunological system of birds, while exemplifying the ability of transcriptomic analyses of detecting early physiological responses to toxicants. As the potentially affected functions are essential for the survival of the animals during, for example, migration, our results underline the need for tight control of the exposure of natural populations of birds to these substances.

Target and untargeted screening of perfluoroalkyl substances in biota using liquid chromatography coupled to quadrupole time of flight mass spectrometry

Perfluoroalkyl substances (PFAS) are known to bioaccumulate and trigger adverse effects in marine birds. This study develops an extraction and analytical methodology for the target/untargeted analysis of PFAS in eggs of Yellow-legged gull (Larus michahellis) and Audouin's gull (Larus audouinii) and blood of Greater flamingo (Phoenicopterus roseus), which are used as bioindicators of organic chemical pollution. Samples were extracted by ultrasonication with acetonitrile and cleaned-up with activated carbon, and analysis was performed by ultra-high-performance liquid chromatography coupled to a quadrupole-time of flight mass spectrometer (UHPLC-Q-TOF) with negative electrospray ionization. Data-independent acquisition (DIA) was performed through full-scan acquisition to obtain MS1 at 6 eV and MS2 at 30 eV. In a first step, quantitative analysis of 25 PFAS was performed using 9 mass-labelled internal standard PFAS and quality parameters of the method developed are provided. Then, an untargeted screening workflow is proposed using the high-resolution PFAS library database from NORMAN to identify new chemicals through accurate mass measurement of MS1 and MS2 signals. The method permitted to detect several PFAS at concentrations ranging from 0.45 to 55.2 ng/g wet weight in gull eggs and from 0.75 to 125 ng/mL wet weight in flamingos' blood, with PFOS, PFOA, PFNA, PFUdA, PFTrDA, PFDoA, PFHxS and PFHpA the main compounds detected. In addition, perfluoro-p-ethylcyclohexylsulfonic acid (PFECHS, CAS number 646-83-3) and 2-(perfluorohexyl)ethanol (6:2 FTOH, CAS number 647-42-7) were tentatively identified. The developed UHPLC-Q-TOF target/untargeted analytical approach increases the scope of PFAS analysis, enabling a better assessment on contaminant exposure and promoting the use of bird species as bioindicators of chemical pollution.

Global ocean contamination of per- and polyfluoroalkyl substances: A review of seabird exposure

Per- and polyfluoroalkyl substances (PFAS) have been extensively produced and used as surfactants and repellents for decades. To date, the global contamination pattern of PFAS in marine biota has seldomly been reviewed. Seabirds are ideal biomonitoring tools to study environmental contaminants and their effects. Here, we compiled and synthesized reported PFAS concentrations in various seabird species to reflect spatiotemporal patterns and exposure risks of major PFAS on a global ocean scale. Perfluorooctane sulfonic acid (PFOS) was the most studied PFAS in seabirds, which showed the highest level in eggs of common guillemots (U. aalge) from the Baltic Sea, followed by great cormorants (P. carbo) from the North Sea and double-crested cormorants (P.auritus) from the San Francisco Bay, whereas the lowest were those reported for Antarctic seabirds. The temporal pattern showed an overall higher level of PFOS in the late 1990s and early 2000s, consistent with the phase-out of perfluorooctane sulfonyl fluoride-based products. Maximum liver PFOS concentrations in several species such as cormorants and fulmars from Europe and North America exceeded the estimated toxicity reference values. Systematic evaluations using representative species and long time-series are necessary to understand contamination patterns in seabirds in South America, Africa, and Asia where information is lacking. In addition, limited research has been conducted on the identification and toxic effects of novel substitutes such as fluorotelomers and ether PFAS (F-53B, Gen-X etc.) in seabirds. Further research, including multi-omics analysis, is needed to comprehensively characterize the exposure and toxicological profiles of PFAS in seabirds and other wildlife.

Legacy and emerging contaminants in flamingos' chicks' blood from the Ebro Delta Natural Park

The Ebro Delta is a wetland of international importance for waterbird conservation but severally affected by intensive agriculture, toxic waste discharges from a past chloro-alkali industry and affluence of tourism. The discharge of contaminants associated to these activities pose waterbirds breeding in the Ebro Delta at risk. The aim of this study is to evaluate the exposure of 91 emerging and legacy micropollutants in flamingo chicks (Phoenicopterus roseus), an emblematic species of the area. Fifty chicks of 45-60 days were captured, biometric parameters measured and whole blood collected. Compounds analyzed included perfluoroalkyl substances (PFASs), pharmaceuticals, organophosphate esters (OPEs), in-use pesticides, polychlorinated biphenyls (PCBs), organochlorine pesticides (OCs), and polycyclic aromatic hydrocarbons (PAHs). The results indicate a multi-exposure of flamingo's chicks from a very young age. PFASs were the most ubiquitous compounds with ∑PFASs ranging from 9.34 to 576 ng/mL, being PFOA, PFOS and PFHxS detected in all samples. ∑PAHs ranged from 0.19 to 423 ng/mL, ∑PCBs from 0.5 to 15.6 ng/mL and ∑OCs from 1.35 to 37.8 ng/mL. Pharmaceuticals, OPEs and in-use pesticides were not detected. The flamingo's filtering behavior on mud and maternal ovo-transference are the more likely routes of exposure of organic micropollutants to flamingos' chicks. The reported levels of micropollutants were not associated with any alteration in the body condition of chicks. This is the first study to describe flamingos chicks' exposure to multiple contaminants, highlighting the importance of biomonitoring for wildlife conservation and biodiversity preservation.

The impact of climate sensitive factors on the exposure to organohalogenated contaminants in an aquatic bird exploiting both marine and freshwater habitats

To assess how climate-sensitive factors may affect the exposure to organochlorines (OCs) and perfluoroalkyl substances (PFASs), we monitored concentrations in eggs of the common goldeneye (Bucephala clangula) over two decades (1999-2019) in central Norway. The goldeneye alternates between marine and freshwater habitats and is sensitive to climate variation, especially due to alterations in ice conditions which may affect feeding conditions. We assessed how biological factors such as diet (stable isotopes δ¹³C and δ¹⁵N), the onset of egg laying, and physical characteristics such as winter climate (North Atlantic Oscillation: NAO_w) influenced exposure. We predicted compounds to show different temporal trends depending on whether they were still in production (i.e. some PFASs) or have been banned (i.e. legacy OCs and some PFASs). Therefore, we controlled for potential temporal trends in all analyses. There were declining trends for α- and γ-hexachlorocyclohexane (HCH), oxychlordane, cis-chlordane, cis-nonachlor, p,p'-dichlorodiphenyltrichloroethane (p.p'-DDT) and less persistent polychlorinated biphenyl (PCB) congeners (e.g. PCB101). In contrast, the dominant compounds, such as p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and persistent PCB congeners, were stable, whereas hexachlorobenzene (HCB) increased over time. Most OCs were positively related to δ¹⁵N, suggesting higher exposure in birds feeding at upper trophic levels. Chlordanes and HCB were positively associated with δ¹³C, indicating traces of marine input for these compounds, whereas the relationships to most PCBs were negative. Among PFASs, perfluorooctanesulfonamide (PFOSA) and perfluorohexane sulfonic acid (PFHxS) declined. Most PFASs were positively associated with δ¹³C, whereas there were no associations with δ¹⁵N. Egg laying date was positively associated to perfluoroheptanesulfonic acid (PFHpS), perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), suggesting that some of the PFAS load originated from the wintering locations. Although NAOw had little impact on the exposure to organohalogenated contaminants, factors sensitive to climate change, especially diet, were associated with the exposure to OHCs in goldeneyes.

Feeding on grains containing pesticide residues is detrimental to offspring development through parental effects in grey partridge

Numerous toxicological studies have shown that ingestion of pesticides can induce physiological stress in breeding birds, with adverse consequences on egg laying parameters and offspring quality through parental effects. However, previous studies do not mimic current levels of pesticide residues in typical landscapes, and they do not consider potential cocktail effects of pesticides as they occur in the wild. Herein, we explored whether realistic pesticide exposure affected reproduction parameters and offspring condition through parental effects in Grey partridge. We fed 24 breeding pairs with either seeds from conventional agriculture crops treated with various pesticides during cropping, or organic grains without pesticide residues as controls. The conventional and organic grain diets mimicked food options potentially encountered by wild birds in the field. The results showed that ingesting low pesticide doses over a long period had consequences on reproduction and offspring quality without altering mortality in parents or chicks. Compared with organic pairs, conventional pairs yielded smaller chicks at hatching that had a lower body mass index at 24 days old. Additionally, these chicks displayed lower haematocrit when body mass index was higher. Therefore, ingestion of conventional grains by parents resulted in chronic exposure to pesticide residues, even at low doses, and this had detrimental consequences on offspring. These results demonstrate a sublethal effect of pesticide residues through parental effects. The consequences of parental exposure on chicks might partly explain the decline in wild Grey partridge populations, which raises questions for avian conservation and demography if current agrosystem approaches are continued.

Perfluoroalkylated compounds in the eggs and feathers of resident and migratory seabirds from the Antarctic Peninsula

In this study, we investigated factors that influence the differences in exposure of perfluoroalkyl acids (PFAAs) from eight species of Antarctic seabirds, including Pygoscelis penguins, Stercorarius maccormicki, and Macronectes giganteus. We analyzed the relationship between foraging ecology (based on δ¹³C, δ¹⁵N, and δ³⁴S values) and PFAAs accumulated in eggs and breast feathers. Ten out of 15 targeted PFAAs were detected in eggs compared to eight in feathers. Mean ∑PFAA concentrations in feathers ranged from 0.47 in P. antarcticus to 17.4 ng/g dry weight (dw) in S. maccormicki. In eggs, ∑PFAA concentrations ranged from 3.51 in P. adeliae to 117 ng/g dw in S. maccormicki. The highest concentrations of most PFAAs were found in trans-equatorial migrators such as S. maccormicki, probably due their high trophic position and higher concentrations of PFAAs in the Northern Hemisphere compared to the Southern Hemisphere. Based on stable isotopes correlations, our results suggest that the trophic position (δ¹⁵N) and the foraging area (δ¹³C and δ³⁴S) influence PFAAs concentrations in Antarctic seabirds. Our results point to the possibility that long-distance migratory birds may have as bio-vectors in the transport of pollutants, including PFCAs, in Antarctic environments, although this must be further confirmed in future studies using a mass balanced approach, such as extractable organofluorine (EOF).

PFAS Molecules: A Major Concern for the Human Health and the Environment

Per- and polyfluoroalkyl substances (PFAS) are a group of over 4700 heterogeneous compounds with amphipathic properties and exceptional stability to chemical and thermal degradation. The unique properties of PFAS compounds has been exploited for almost 60 years and has largely contributed to their wide applicability over a vast range of industrial, professional and non-professional uses. However, increasing evidence indicate that these compounds represent also a serious concern for both wildlife and human health as a result of their ubiquitous distribution, their extreme persistence and their bioaccumulative potential. In light of the adverse effects that have been already documented in biota and human populations or that might occur in absence of prompt interventions, the competent authorities in matter of health and environment protection, the industries as well as scientists are cooperating to identify the most appropriate regulatory measures, substitution plans and remediation technologies to mitigate PFAS impacts. In this review, starting from PFAS chemistry, uses and environmental fate, we summarize the current knowledge on PFAS occurrence in different environmental media and their effects on living organisms, with a particular emphasis on humans. Also, we describe present and provisional legislative measures in the European Union framework strategy to regulate PFAS manufacture, import and use as well as some of the most promising treatment technologies designed to remediate PFAS contamination in different environmental compartments.

Distribution and ten-year temporal trends (2009-2018) of perfluoroalkyl substances in gull eggs from Spanish breeding colonies

Gull eggs are excellent bioindicators of environmental pollution as reflect the contamination levels of coastal areas, especially of persistent and bioacumulative compounds such as perfluoroalkyl substances (PFAS). This study aims to evaluate the geographical distribution and 10-year temporal trends (2009-2018) of 17 PFAS in eggs of two gull species (Larus michahellis and Larus audouinii) from 5 main Spanish colonies. ∑PFAS ranged from 13.7 ± 5.9 to 164 ± 17 ng g^-1 wet weight and higher concentrations were observed in L. audouinii than in L. michahellis. Perfluorooctane sulfonate (PFOS) was the predominant compound in all samples, followed by perfluoroundecanoic acid (PFUnA) and perfluorotridecanoic acid (PFTriDA). Perfluorododecanoic acid (PFDoA), perfluorodecanoic acid (PFDA) and perfluorooctanoic acid (PFNA) were also found in all studied areas but at lower concentrations, while perfluorooctanoic acid (PFOA) was only detected in the Medes Islands. Principal Component Analysis revealed the co-occurrence of the 6 detected PFAS, and differentiated samples from Ebro Delta and Medes Islands, both located in the North-Eastern Mediterranean Sea, with high contribution of all PFAS, from Chafarinas and Atlantic Islands with lower concentration levels and variability. Also, different patterns were observed among colonies, suggesting the fish-based diet plays an important role in PFAS bioaccumulation. In all colonies, except for the Medes Islands, ∑PFAS decreased through the 10-year study period, with PFOS, PFUnA, and PFTriDA showing a significant concentration reduction in a colony-specific manner. This study demonstrates the usefulness and importance of continuous systematic long-term monitoring to determine the geographical distribution and temporal variations of PFAS in marine protected areas using gull eggs as bioindicators of environmental pollution.

Assessment of regional and temporal trends in per- and polyfluoroalkyl substances using the Oriental Magpie (Pica serica) in Korea

Per- and polyfluoroalkyl substances (PFASs) are used in industrial and commercial products due to their amphiphilic properties. Birds have been utilized as biomonitoring species due to their environmental pollutant vulnerability and wide distribution. The Oriental Magpie (Pica serica) is a representative residential species inhabiting terrestrial environments. In this study, we measured PFAS concentrations in Magpie liver tissue (n = 253) collected from 12 Korean regions in 2004 and 2017. The predominant compounds were perfluorooctanesulfonic acid (PFOS; mean: 23.8 ng/g wet weight), perfluorotridecanoic acid (PFTrDA; 2.79 ng/g), and perfluoroundecanoic acid (PFUnDA: 2.11 ng/g). We observed significant correlations between Magpie PFAS measurements, indicating similar sources and bioaccumulation processes. Adult females showed significantly lower PFOS concentrations than adult males and young males and females, indicating that avian sex is a crucial physiological factor of PFAS accumulation. PFOS, perfluorodecanoic acid (PFDA), and perfluorotetradecanoic acid (PFTeDA) concentrations in urban regions were significantly higher than rural regions. PFOS concentrations in Magpie livers increased significantly between sampling years, whereas C11-C13 carboxylic acids (PFCAs) decreased. This suggests that urbanization and population are major factors in Magpie PFAS accumulation. Almost all hepatic PFOS concentrations were below the threshold values proposed by previous studies, implying limited risks. Our findings suggest that the Oriental Magpies are PFAS sentinel in residential environments. This is the first comprehensive report on biomonitoring of PFASs using the Oriental Magpie.

Maternal transfer and occurrence of siloxanes, chlorinated paraffins, metals, PFAS and legacy POPs in herring gulls (Larus argentatus) of different urban influence

Urban herring gulls (Larus argentatus) are exposed to contaminants from aquatic, terrestrial and anthropogenic sources. We aim to assess if differences in urbanisation affect ecological niche and contaminant concentrations in female herring gulls. Furthermore, we investigated maternal transfer from mothers to eggs for all the target compounds, including chlorinated paraffins (CPs) and cyclic volatile methyl siloxane (cVMSs), which to our knowledge have not been assessed in herring gulls previously. We compare concentrations of legacy and emerging contaminants and metals in blood and eggs between two herring gull colonies located 51 km apart, in the urban influenced Norwegian Oslofjord. While both colonies are within an urbanised area, the inner fjord is more so, as it is surrounded by Oslo, the capital and largest city in Norway Stable isotopes of carbon and nitrogen indicated a more marine ecological niche in the outer than the inner fjord colony, although with overlap. Persistent organic pollutant (POP) concentrations were similar in the inner and outer fjord colonies, while the short-chained chlorinated paraffins (SCCP), which are recently added to the Stockholm convention and contaminants of emerging concern (CECs) varied, with higher concentrations of SCCP and the cVMS decamethylcyclopentasiloxane (D5) in females and eggs of the inner fjord colony. Per- and polyfluorinated substances (PFAS) concentrations were higher in the outer fjord colony, likely linked to releases from a point-source (airport and waste management facility with open access to food waste). In blood, chlorinated paraffins contributed most the total lipophilic contaminants (inner: 78%, outer: 56%), while polychlorinated biphenyls (PCBs) were the most abundant lipophilic contaminants in eggs (inner: 62%, outer: 46%). Dechloranes and brominated flame retardants (BFRs) were detected in few samples. Maternal transfer, assessed by egg to blood ratios, of cVMSs were similar to the POPs with mean log ratio 0.39 (D5), while it was lower for SCCPs, with log ratios-0.77. Our results indicate comparable POP exposure of the herring gulls in the inner and outer Oslofjord, likely due to overlap in ecological niches between the colonies and wide distribution of POPs. The differences between the colonies in concentrations of PFAS, cVMS and CPs shows that point source exposures and urban influence may be more important than ecological niche for these compounds.