Levels and profiles of perfluorinated alkyl acids in liver tissues of birds with different habitat types and trophic levels from an urbanized coastal region of South Korea

Legacy and emerging persistent organic pollutants in sea turtles from Korean waters: Levels, profiles, and interspecies differences

Sea turtles, as endangered species with their long lifespans, wide-ranging migration, and high trophic level, are effective bioindicators of marine pollution. Despite the importance of global monitoring of persistent organic pollutants (POPs) in sea turtles, research has been limited, especially in Asia. This study examined the accumulation of POPs in the livers of 44 sea turtles from Korean waters, including loggerhead (Caretta caretta) and green turtles (Chelonia mydas). The turtles accumulated the chemicals in the order PAHs > PCBs > DDTs > PBDEs > CHLs, HBCDs, hexachlorobenzene, HCHs > mirex, pentachlorobenzene. Loggerhead turtles had significantly higher levels of DDTs, HCHs, pentachlorobenzene, and PBDEs than green turtles (Wilcoxon rank sum test, p < 0.01), along with a higher proportion of bioaccumulative congeners and isomers, likely due to their primarily carnivorous diet compared to the predominantly herbivorous diet of green turtles. Conversely, HBCD levels were similar in both species, yet green turtles had a higher proportion of γ-HBCD-the dominant isomer in commercial HBCDs used as plastic additives, with lower bioaccumulation potential-likely reflecting their greater ingestion of plastic debris than loggerhead turtles. Notably, sea turtles had higher ratios of γ-HBCD to α-HBCD and HBCDs to PCBs than seabirds from Korean waters, implying greater exposure to plastic-derived POPs. This study highlights the widespread accumulation of legacy and emerging POPs, including plastic-associated chemicals, in Korean sea turtles. These findings underscore the need for global POP monitoring in sea turtles and further research on the environmental fate and impact of plastic-associated chemicals.

Hair analysis as a non-invasive method for assessing the exposure of wildlife to per- and poly-fluoroalkyl substances (PFAS)

In mammals, exposure to PFAS is usually assessed by measuring burdens in internal organs (i.e., liver and brain) or plasma, while less emphasis is devoted to non-invasive and non-destructive methods. We assess the suitability of hair as a non-invasive matrix for monitoring the exposure of mammals to 33 PFAS, including perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkane sulfonic acids (PFSAs), perfluoroalkylether carboxylic acids (PFECAs), perfluoroalkylether sulfonic acids (PFESAs), perfluoroalkane sulfonyl fluoride-based substances (PASFs), and fluorotelomers (FTs). The Red fox is chosen as the target species due to its apical position in the terrestrial food web of the study area, the Cavallino-Treporti peninsula in North-East Italy. All analysed samples (n = 24) are positive for PFAS, with eight compounds quantified in all samples, including PFHxA, PFOA, PFDA, PFUnDA, PFDoDA, PFTriDA, PFTeDA, and PFOS. The highest mean concentration in hair samples is measured for PFOS (1.40 ± 0.48 ng g-1 dw) followed by PFDoDA (0.31 ± 0.05 ng g-1 dw), and PFOA (0.31 ± 0.19 ng g-1 dw), while the mean ∑33PFAS was 3.41 ± 0.93 ng g-1 dw. The dominance of PFOS and long-chain PFAS in the PFAS profile and the occurrence of compounds with even-numbered carbon chains at higher concentrations than the odd-numbered compounds with a one-carbon longer chain (i.e., PFOA > PFNA, PFDA > PFUnDA, PFDoDA > PFTriDA) suggest the trophic transfer along the terrestrial food web as the primary exposure pathway in the study area. The data suggest hair analysis as a reliable, non-invasive method for assessing the possible exposure of mammals to PFAS and suggested that the Red fox can be used as a sentinel of the environment, embracing the One Health perspective.

Per- and polyfluoroalkyl substance profiles revealed by targeted and non-targeted screening in European starling eggs from sites across Canada

Per- and polyfluoroalkyl substances (PFAS) are environmental contaminants including in wildlife but are a fraction of the growing 1000s of PFAS that are being produced. Our study objective was to determine and compare PFAS profiles using targeted analysis and non-targeted analysis (NTA) methods in European starling (Sturnus vulgaris) eggs collected in April/May of 2023 from 11 nesting box sites across Canada at locations described as landfills, near parks, forest, urban, near wastewater facilities, rural, waste management facilities and urban industrial. NTA revealed 41 PFAS at variable detection frequencies in eggs samples and up to 29 PFAS were quantifiable by targeted method analysis. The Σ29PFAS mean concentration (range) (1048 (991-1078) ng/g ww) at the lone landfill site at Brantford were the highest whereas all other sites were <151 ng/g w.w. Σ29PFAS concentrations were not significantly different (p < 0.05) among the 10 non-Brantford landfill sites including the Nova Scotia hospital site (range of 58.0-152 ng/g ww). Two side-chain fluorinated polymer surfactants for a sub-set of egg pools, and 4 emerging PFAS including GenX (or HFPO-DA), F-53B components and ADONA for all pools were not detectable. Confirmed against in-house synthesized standards, 8:2 FTOH sulfate, was detected in 93 % of all samples, and 6:2, 10:2, and 12:2 FTOH sulfates were also detected only in Brantford landfill site eggs. FTOHs, which are likely precursors of FTOH sulfate metabolites, were not detectable in any samples. This suggested that FTOH sulfate metabolites may be suitable biomarkers of exposure to FTOHs and perhaps other PFAS. Among all nest box locations, other additional NTA detected PFAS in eggs were e.g. branched isomers of PFOA, PFHpS, PFNS and PFDS and 6:2 diPAP. Overall, more targeted PFAS candidates should be monitored in starling eggs.

Trends in extraction techniques for the determination of organic micropollutants in liver tissues of vertebrates

Determining organic micropollutants in liver samples of apex species is of foremost importance for biomonitoring studies, as it can provide evidence of environmental pollution and exposure of living organisms to chemicals. This review aims to provide a 4-year overview and summarize the trends in the extraction methodologies to determine both polar and non-polar organic micropollutants in liver samples from organisms of higher trophic levels. The dominant extraction techniques including ultrasound-assisted extraction (UAE), pressurized liquid extraction (PLE), Soxhlet, and QuEChERS, as well as additional steps and/or modifications applied in the reviewed studies, are presented and critically discussed. The latest trends in these methods as well as a comparison between them considering elapsed time, robustness, cost, and environmental fingerprint are also provided.

A 20-year study reveal decrease in per- and polyfluoroalkyl substances (PFAS) in a pelagic seabird from the Western Mediterranean Sea

Despite the first ban on perfluorooctane sulfonic acid (PFOS) in 2009, it remains unclear whether Europe, a key regulator, has effectively reduced per- and polyfluoroalkyl substances (PFAS) in the environment over the past 20 years. This study investigates the levels and temporal trends of 19 PFAS compounds in the livers of 62 Scopoli's shearwaters (Calonectris diomedea) collected from the Mediterranean basin during 2003-2022. Over the past two decades, PFAS concentrations showed an overall significant decrease of 77%. PFOS was the most frequently and predominantly detected chemical in livers, closely followed by perfluorotridecanoic acid (PFTrDA) and perfluoroundecanoic acid (PFUnDA). However, the contribution of PFTrDA (32.4%) surpassed that of PFOS (30.3%) in 2009-2014, which can be attributed to its increased use as a substitute following the regulation on PFOS in 2009. Perfluoroalkyl carboxylic acids (PFCAs), along with PFOS, showed a general decline over the study periods, with the largest decrease occurring after 2015, corresponding to the regulations on PFCAs. An odd-numbered, long-chain PFCAs accumulation trend was observed in samples. Principal component analysis showed a shift from PFOS to PFCAs in Scopoli's shearwater PFAS patterns over 20 years. Our results offer valuable insights into the environmental behavior of PFAS, the complex interactions between regulations and compounds and their transfer to the marine ecosystems. Despite widespread declines, their persistent detection underscores the need for enhanced international cooperation efforts to comprehensively mitigate PFAS emissions, including those from developing regions and unregulated sources.

Innovative approach for environmental pollution assessment using seabird eggs: mercury in black-tailed gull (Larus crassirostris) eggs from the Korean islands (2012-2021)

Since black-tailed gulls derive energy for egg production around their habitat, analyzing concentration of chemicals in the eggs reveals the local environmental pollution. This is, however, complex due to the diversity of seabird diets across multiple ecosystems. This study determined the influence of food source and trophic position (TP) on the mercury concentration ([Hg]) in eggs and subsequently mitigated these influences by adjusting through [Hg]-TP relationship, thereby enabling spatial and temporal comparisons among individuals. Following TP adjustment, the [Hg] that previously exhibited significant regional differences no longer displayed such a variation. Moreover, by normalizing to trophic level 4, as suggested by the European Union (EU), the total [Hg] was standardized from 1001 ± 415 ng g-1 to 1347 ± 516 ng g-1 in all the egg samples, far exceeding the EU criteria. These two approaches provide valuable insights for the effective monitoring of marine pollution and past environmental reconstruction by adjusting/normalizing [Hg] in seabird eggs.

Per- and polyfluoroalkyl substances in waterbird feathers around Poyang Lake, China: Compound and species-specific bioaccumulation

As a nondestructive means of environmental monitoring, bird feathers have been used to analyze levels of per- and polyfluoroalkyl substances (PFASs) in specific environments. In this study, feather samples from 10 waterbird species around Poyang Lake were collected, and a pretreatment method for PFASs in feathers was optimized. The results showed that a combined cleaning method using ultrapure water and n-hexane effectively removed external PFASs. Twenty-three legacy and emerging PFASs were identified in the feathers of waterbirds, of which hexafluoropropylene oxides (HFPOs), chlorinated polyfluoroalkyl ether sulfonates (Cl-PFESAs), and sodium p-perfluorinated noneoxybenzene sulfonate (OBS) were reported for the first time, with their concentrations ranging from 0.060-2.4 ng·g-1 dw, 0.046-30 ng·g-1 dw, and lower than the method detection limit to 30 ng·g-1 dw, respectively. Compound- and species-specific bioaccumulation of PFASs was observed in the feathers of different waterbird species, suggesting that different PFAS types can be monitored through the selection of different species. Moreover, the concentrations of most PFCAs (except perfluorobutyric acid), perfluorooctane sulfonate (PFOS), and perfluorooctane sulfonamide (FOSA) were significantly positively correlated with δ15N (p < 0.05), while the concentrations of HFPOs, Cl-PFESAs, and OBS had significant positive correlations with δ13C. This indicates that the bioaccumulation of legacy and emerging PFASs in waterbird feathers is affected by their trophic level, feeding habits, and foraging area.

Integrated approach for the isotope trophic position of black-tailed gull (Larus crassirostris) eggs over a decade: Combining stable isotopes of amino acids and fatty acids composition

Recently, compound-specific isotope analysis (CSIA) using the amino acid nitrogen stable isotope ratio (δ15NAAs) has been widely used for accurate estimation of trophic position (TP). In addition, a quantitative fatty acid signature analysis (QFASA) offers insights into diet sources. In this study, we used these techniques to estimate the TP for seabirds that rely on diverse food sources across multiple ecosystems. This allows for the proper combination of factors used in TP calculation which are different for each ecosystem. The approach involved the application of a multi-mixing trophic discrimination factor (TDF) and mixing β which is a Δδ15N between trophic and source amino acid of primary producer. Since the black-tailed gulls (BTGs) are income-breeding seabirds, which rely on energy sources obtained around their breeding sites, they and their eggs could be useful bioindicators for environmental monitoring. However, the ecological properties of BTGs such as habitats, diets, and TP are not well known due to their large migration range for wintering or breeding and their feeding habits on both aquatic and terrestrial prey. In this study, the eggs were used for estimating TP and for predicting TP of mother birds to overcome difficulties such as capturing birds and collecting non-invasive tissue samples. Eggs, sampled over a decade from three Korean islands, showed spatial differences in diet origin. Considering both the food chain and physiology of BTG, the TP of eggs was estimated to be 3.3-4.0. Notably, the TP was significantly higher at site H (3.8 ± 0.1) than at site B (3.5 ± 0.2), which indicated a higher contribution of marine diet as confirmed by QFASA. Using a reproductive shift of δ15NAAs, the TP of the mother birds was predicted to be 3.6-4.3, positioning them as the top predator in the food web. The advanced integration of multiple approaches provides valuable insights into bird ecology.

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.

Spatial distribution and temporal trends of classical and emerging persistent organic pollutants (POPs) in black-tailed gull (Larus crassirostris) eggs from Korea

This study monitored the spatiotemporal trends of persistent organic pollutants (POPs) contamination along the Korean coasts using eggs of the black-tailed gull, a resident bird that occupies a high trophic position in the marine food web. Black-tailed gull eggs were collected from three breeding islands located in the western (Seoman-do), southern (Hong-do), and eastern (Dok-do) seas of Korea during 2015-2019, and egg contents were analyzed for classical and emerging POPs. Among the target analytes, levels of emerging POPs such as brominated flame retardants (BFRs) and perfluoroalkyl acids (PFAAs) were significantly higher in eggs from Seoman-do than other islands. Global positioning system tracking data show that seagulls from Seoman-do traveled frequently to two neighboring major cities (Incheon and Seoul), indicating that the accumulation of BFRs and PFAAs in bird eggs is directly affected by the pollution characteristics of urban areas. Overall, the ratios of PFAA and BFR to the total POPs in eggs from the islands increased over time, while the proportion of classical POPs decreased. A shift from classical POPs to BFRs and PFAAs in seagull eggs was identified. Interestingly, perfluorooctanoic acid (PFOA), which exhibits limited bioaccumulation, was detected at higher levels in eggs from Seoman-do, indicating widespread use of PFOA and maternal transfer to seabird eggs. Continuous monitoring of PFAAs in marine environments of Korea is needed. This study demonstrates that monitoring of seabird eggs is effective for detecting spatial and temporal trends of POPs in the marine environment, and provides insights into emerging POPs such as PFAAs.