Geographic and trophic patterns of OCs in pelagic seabirds from the NE Atlantic and the Mediterranean: a multi-species/multi-locality approach

Influence of paternal factors on plastic ingestion and brominated chemical exposure in East Tropical Atlantic Procellariid chicks

The presence of plastic debris and organo-brominated compounds in the marine environment poses a concern to wildlife. Plastic can absorb and release chemical compounds, making their ingestion potentially harmful, while chemical compounds have become omnipresent, with a tendency to bioaccumulate in the food web. Seabirds are often used as indicators of marine plastic pollution, yet studies on the exposure of tropical communities to plastic contamination are still scarce. In this study we monitored the amounts of plastics in faeces and organo-brominated compounds ingested/assimilated in feathers by adults and chicks of Cape Verde shearwaters and Bulwer's petrels from Cabo Verde. Anthropogenic pollutants, polybrominated diphenyl ethers (PBDEs), and naturally generated methoxylated-PBDEs (MeO-PBDEs) were among the probed compounds. The frequency of plastic debris ingestion was similar in both species' adults and chicks, although, the characteristics of the ingested plastic differed. Frequency and number of microplastics increased throughout the nestling season for chicks from both species. All species and age groups showed the presence of PBDEs and MeO-PBDEs. Among PBDEs, Bulwer's petrels exhibited higher concentrations than Cape Verde shearwaters, and chicks had higher concentration profiles than adults. Specifically, Bulwer's petrel chicks showed higher concentrations than Cape Verde shearwater chicks. On the contrary, Cape Verde shearwater adults exhibited higher occurrence and concentrations of MeO-PBDEs when compared to Cape Verde shearwater chicks. We found no effect of plastic loadings or loadings of organohalogen contaminants on body condition or size, although harmful effects may be hidden or reveal themselves in a medium- to long-term. Feather samples from both adults and chicks were shown to be useful for comparing intraspecific contamination levels and appear suitable for the long-term assessment of organohalogen contaminants in seabirds. Species-specific foraging and feeding strategies are likely the drivers of the observed variation in organochlorine contamination burdens among seabird species.

Blood Kinetics of Lipophilic and Proteinophilic Pollutants during Two Types of Long-Term Fast in King Penguins

In vertebrates, fasting is an intricate physiological process associated with strong metabolic changes, yet its effect on pollutant residue variation is poorly understood. Here, we quantified long-term changes in plasma concentrations of 20 organochlorine and 16 perfluoroalkyl pollutants in king penguins Aptenodytes patagonicus during the breeding and molting fasts, which are marked by low and high levels of protein catabolism, respectively, and by strong lipid use. The profile of measured pollutants in plasma was dominated by perfluorooctanesulfonic acid (PFOS, initial relative contribution of 60%). Initial total pollutant concentrations were similar in molting (3.3-5.7 ng g-1 ww) and breeding penguins (range of 4.2-7.3 ng g-1 wet weight, ww). Long-term fasting (25 days) for molting and breeding led, respectively, to a 1.8- and 2.2-fold increase in total plasma pollutant concentrations, although the rate and direction of change were compound-specific. Hexachlorbenzene (HCB) and PFOS concentrations increased in plasma (net mobilization) during both types of fasting, likely due to lipid use. Plasma perfluoroundecanoate (PFUnDA) and perfluorotridecanoate (PFTrDA) concentrations increased in breeders (net mobilization) but decreased in molting individuals (net excretion), suggesting a significant incorporation of these pollutants into feathers. This study is a key contribution to our understanding of pollutant variation in blood during long-term fasting in wildlife.

Microplastics ingestion and endocrine disrupting chemicals (EDCs) by breeding seabirds in the east tropical Atlantic: Associations with trophic and foraging proxies (δ15N and δ13C)

In this study we found that endocrine disrupting chemicals (EDCs) were omnipresent in a tropical seabird community comprising diverse ecological guilds and distinct foraging and trophic preferences. Because EDCs tend to bioaccumulate within the food web and microplastics can absorb and release harmful chemical compounds, our findings draw attention to the potential threats to wildlife. Thus, the goal of this study was to investigate the role of plastic ingestion, trophic and foraging patterns (δ15N and δ13C) of five tropical seabird species breeding in sympatry, on the exposure to EDCs, namely Polybrominated diphenyl ethers (PBDEs), methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and personal care products (PCPs, e.g., musk fragrances and UV-filters). Results indicated that microplastics occurrence and EDCs detection frequency varied among species. Microplastics occurrence was higher in species with dual and coastal foraging strategies. Preen oil had higher levels of MeO-PBDEs and PCPs, while serum had higher levels of PBDEs. In brown boobies, the correlation between microplastics and ∑PBDEs levels was significant, suggesting that microplastics ingestion is a key PBDEs route. Trophic position (δ15N) plays a key role in PBDEs accumulation, particularly in Bulwer's petrel, which occupies a high trophic position and had more specialized feeding ecology than the other species. MeO-PBDEs were linked to foraging habitat (δ13C), although the link to foraging locations deserves further investigation. Overall, our findings not only fill key gaps in our understanding of seabirds' exposure to microplastics and EDCs, but also provide an essential baseline for future research and monitoring efforts. These findings have broader implications for the marine wildlife conservation and pollution management in sensitive environments, such as the tropical regions off West Africa.

Persistent organic pollutant patterns in seabirds from marine protected areas in the tropical Atlantic Ocean

Persistent organic pollutants were investigated in the blood of living seabirds (Pterodroma arminjoniana, Onychoprion fuscatus, Sula dactylatra, Anous minutus, Anous stolidus and Sula leucogaster) from two Brazilian Conservation Units - Trindade Island and São Pedro and São Paulo Archipelago. ∑PCBs (0.55 to 55.09 ng/g wet weight (ww), ∑DDTs (0.01 to 17.36 ng/g ww) and Mirex (0.01 to 5.53 ng/g ww) were predominant in all samples. Trindade petrel Pterodroma arminjoniana presented higher values than other seabirds, which is potentially related to diet and migratory behavior. Fluctuations in the trophic ecology data, through carbon and nitrogen stable isotope ratios, warn of temporal variation in diet and foraging and highlight the importance of using a nondestructive matrix to allow long-term monitoring of POP contamination in seabirds from Brazilian Conservation Units. In addition, the data will fill the gaps in the POP baselines for seabirds from the tropical Atlantic Ocean.

Microplastics ingestion and chemical pollutants in seabirds of Gran Canaria (Canary Islands, Spain)

Plastic pollution constitutes an environmental problem in the Canary Islands nowadays. Nevertheless, studies evaluating the impact of plastics on its avifauna are still scarce. Gastrointestinal tracts of 88 birds belonging to 14 species were studied for the presence of plastics. Moreover, their livers were analyzed for the determination of bromodiphenyl ethers (BDEs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs). Among Cory's shearwaters (n = 45), the frequency of occurrence of plastic ingestion was considerably high (88.89 %). This species had the highest mean value of items (7.22 ± 5.66) and most of them were compatible with lines derived from fishing gear. PCBs and PAHs were detected in all of the samples and OCPs in the great majority of them (98.86 %). Our results highlight the problems that plastic debris (mainly for seabirds) and organic pollutants pose to these species.

Year-round element quantification of a wide-ranging seabird and their relationships with oxidative stress, trophic ecology, and foraging patterns

Multidisciplinary approaches are essential to diligently assess environmental health status of ecosystems. In this study, year-round chemical elements' exposure and impacts were assessed on the wide-ranging Cory's shearwater Calonectris borealis breeding in Berlenga Island, offshore Portugal, North Atlantic Ocean. The aim was to identify potential contamination and oxidative stress sources associated with trophic ecology, habitat and spatial use, and foraging patterns. A set of 20 chemical elements were quantified, along with oxidative stress biomarkers, stable isotope analyses, and GPS tracking data. Birds presented higher accumulation to some non-essential elements along the year (i.e. arsenic, As; cadmium, Cd; mercury, Hg; lead, Pb; and strontium, Sr), in which concentrations were similar or surpassed other procellariform seabird populations all over the world. No significant differences were found for any of the elements between different periods within the breeding season, with exception of Hg. However, a Principal Component Analysis taking into consideration a group of elements showed differences between pre-laying and chick-rearing periods, with overall higher concentrations in the former. Individuals spending more time engaging in an intensive search for food, and in more coastal environments, presented overall higher element concentrations, and particularly Hg. Contrary to expectations, no relationships were found between chemical elements and oxidative stress. On the other hand, spatial use and foraging patterns of Cory's shearwaters influenced their oxidative stress responses. Our results highlight the need for multidisciplinary approaches to deepen understanding of the large-scale vulnerability of bioindicators such as seabirds and, by extension, the overall environmental health of ecosystems in which they rely.

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 natural products in birds associated with the marine environment: A review

Halogenated natural products (HNPs) are widespread compounds found at high concentrations in top predators such as seabirds. This paper reviews available data on methoxylated polybrominated diphenyl ethers (MeO-BDEs), heptachloro-1'-methyl-1,2'-bipyrrole (Q1) and 1,1'-dimethyl-2,2'-bipyrroles (HDBPs) in these animals. In all, 25 papers reported such HNPs in seabirds. White tailed sea eagle from Sweden was the seabird species with higher MeO-BDEs levels in eggs and blood, while in liver the European shag from Norway was the one. Regarding HDBPs, glaucous gull livers from North Water Polynya and Leach's storm petrel eggs from South Canada (NE Atlantic) showed the highest levels, while brown skua eggs presented the highest concentration of Q1. DBP-Br₄Cl₂ and DBP-Br₆ were the most abundant HDBPs in seabirds, although only one study investigated DBP-Br₆. Furthermore, 2'-MeO-BDE-68/6'-MeO-BDE-47 ratios were lower than one in mostly of the studies (91%). The main sources of methoxylated congeners found in seabirds might to be from sponges and/or associated organisms (bacteria). The scarcity of data in seabirds showed the gap in knowledge. Few studies were done especially in tropical areas and Southern Hemisphere and the most were conducted in the northwest part of the globe. This review arouses the need of knowledge about the distribution of these compounds in seabirds worldwide as well as it encourages toxicological studies to better understand the possible effects of HNPs on seabirds.

Trace metal blood concentrations in Scopoli's shearwaters (Calonectris diomedea) during 2007-2014: A systematic analysis of the largest species colony in Greece

In this study, the concentrations of cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu), cobalt (Co), nickel (Ni), manganese (Mn) and zinc (Zn) were investigated in the blood of Scopoli's shearwaters (Calonectris diomedea). Blood samples (N=238) were collected from both juvenile and adult individuals during seven breeding seasons between 2007 and 2014, excluding 2013. Sampling was performed in the pristine environment of the Strofades island complex, Greece, where the largest colony of Scopoli's shearwaters is located in the Eastern Mediterranean basin. The median concentrations of the toxic metals, Cd and Pb, were 0.010 and 0.24μg/g (dry weight; dw), respectively, which were in good agreement with previous studies. The median concentrations of Co, Cr, Cu, Mn, Ni, Zn were 0.18, 1.11, 3.41, 0.29, 0.61, and 22.9μg/g dw, respectively. Inter-annual differences were observed among the concentrations of all assessed metals, except for Ni and Cd, which demonstrated similarities among female individuals. Age-group related differences were observed in both genders for Cd, Cu and Cr, but only among males for Zn. To the best of our knowledge, this is the longest multi-year biomonitoring study of select trace metals that has been conducted thus far on blood samples from Scopoli's shearwater species.

Spatial and Interspecies Heterogeneity in Concentrations of Perfluoroalkyl Substances (PFASs) in Seabirds of the Southern Ocean

In this study, we evaluate the main factors driving the exposure of Southern Ocean seabirds to perfluoroalkyl substances (PFASs) across a wide geographic range. Five perfluoroalkane sulfonates (PFSAs, C_4-12), 10 perfluoroalkyl carboxylic acids (PFCAs, C_4-13), and perfluorooctane sulfonamide (FOSA) were analyzed in plasma (n = 128) from eight species, including penguins, giant petrels, skuas, albatrosses, and shearwaters, breeding at four sites in the Antarctic, sub-Antarctic, and adjacent cool-temperate regions. Mean ∑PFAS concentrations ranged from 0.53 to 53 ng/g wet weight from black-browed albatross to giant petrels, respectively. As expected due to biomagnification, greater concentrations of most PFASs were found in species near the top of marine food webs such as giant petrels. However, our results suggest that other factors, i.e., metabolic capabilities and spatial movements, can mask interspecies differences in PFASs, especially PFCAs, expected from trophic structure. For instance, trans-equatorial migratory seabirds exhibited PFAS levels and profiles that are consistent with northern hemisphere exposure, reflecting their potential biovector role in the global transport of these pollutants. Among resident species, greater concentrations of PFASs, especially long-chain PFCAs, were found in seabirds breeding or foraging north of the Antarctic Circumpolar Current (ACC) than in those restricted to Antarctic/sub-Antarctic distributions. Moreover, composition profiles of PFAS in Antarctic seabirds agree well with those expected from long-range transport. Our results confirm the importance of the ACC in protecting Antarctic food webs from water-phase-transported PFASs.

Contrasting congener profiles for persistent organic pollutants and PAH monitoring in European storm petrels (Hydrobates pelagicus) breeding in Ireland: a preen oil versus feathers approach

Persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) are anthropogenic contaminants of environmental concern due to their persistence in the environment and capacity to accumulate in biota. Many of these contaminants have been found to have ill effects over wildlife and humans. Birds are known to be particularly affected through endocrine disruption and eggshell thinning. POPs have been banned or restricted through the Stockholm Convention (2001), making monitoring essential for tracking effects of regulation. Seabirds have been used as monitoring tools for being top predators and consuming a diverse array of prey in different trophic levels. Non-destructive sampling has become widely popular using feathers and preen oil, as opposed to carcasses and internal organs. This study aimed to set baseline levels of POP and PAH concentration in a highly pelagic and abundant seabird in Ireland and the Atlantic, the European storm petrel, Hydrobates pelagicus, and to investigate the profiles of contaminant congeners in preen oil and feathers, comparatively. Mean concentrations in preen oil followed: PCB (10.1 ng/g ww) > PAH (7.1 ng/g ww) > OCP (5.4 ng/g ww) > PBDE (3.9 ng/g ww), whilst mean concentrations in feathers followed the order: PAH (38.9 ng/g ww) > PCB (27.2 ng/g ww) > OCP (17.9 ng/g ww) > PBDE (4.5 ng/g ww). Congener profiles highly differed between preen oil and feathers, and little correlation was found between the matrices. These results demonstrate that the sampling of a single matrix alone (preen oil or feathers) might produce confounding results on contamination in seabirds and that more than one matrix is recommended to obtain a full picture of contamination by persistent organic pollutants.

Temporal trends of mercury and organohalogen contaminants in great blue heron eggs from the St. Lawrence River, Québec, Canada, 1991-2011, and relationships with tracers of feeding ecology

Since 1991, great blue heron (Ardea herodias) eggs have been collected and analyzed for mercury (Hg), persistent organic contaminants (OCs), brominated and non-brominated flame retardants (FRs) as well as stable isotopes δ¹³C and δ¹⁵N. In the present study, temporal trends of contaminants were analyzed in eggs sampled in four regions along the St. Lawrence River (Quebec, Canada) and inland sites using new and previously published data. Most contaminants declined significantly over time in most regions. Globally, the highest annual change, -17.5%, was found for pp'-DDD, while the smallest annual decline, -0.54%, was observed for Hg. Concentrations of ΣDDT and ΣFR₈ (sum of 8 congeners) decreased by -11.6% and -7.3%, respectively. Declines in ΣPCBs differed among regions, from -5.6% in the fluvial section to -14.7% in the inland region. The highest concentration of ΣFR₈ was measured in eggs from Grande Ile in the fluvial section of the river in 1996 (2.39μg/g). Stable isotope ratios also showed temporal trends in some regions: δ¹³C decreased in the fluvial section and increased in Gulf region, while δ¹⁵N decreased in the fluvial section and increased in the upper estuary. Significant positive relationships were found between ΣDDT, ΣPCBs and ΣFRs and δ¹⁵N and δ¹³C in freshwater colonies, but not in estuarine or marine colonies. These results suggest that changes in trophic level and foraging areas over time were influential factors with respect to contaminant burden in great blue heron eggs in the fluvial section, but not in the other regions.

Relationship between legacy and emerging organic pollutants in Antarctic seabirds and their foraging ecology as shown by δ13C and δ15N

Foraging ecology and the marine regions exploited by Antarctic seabirds outside of breeding strongly influence their exposure to persistent organic pollutants (POPs). However, relationships between them are largely unknown, an important knowledge gap given that many species are capital breeders and POPs may be deleterious to seabirds. This study investigates the relationship between Antarctic seabird foraging ecology (measured by δ¹³C and δ¹⁵N) and POPs accumulated in their eggs prior to breeding. Organochlorinated pesticides, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and dechlorane plus (DP) were measured in eggs of chinstrap, Adélie, and gentoo penguins (Pygoscelis antarctica, P. adeliae, P. papua), as well as south polar skua (Catharacta maccormicki), sampled on King George Island. Total POP levels were as follows: skua (3210±3330ng/g lipid weight)>chinstrap (338±128ng/g)>Adélie (287±43.3ng/g)>gentoo (252±49.4ng/g). Trophic position and pre-breeding foraging sites were important in explaining POP accumulation patterns across species. The most recalcitrant compounds were preferentially accumulated in skuas, occupying one trophic level above penguins. In contrast, their Antarctic endemism, coupled with influence from cold condensation of pollutants, likely contributed to penguins exhibiting higher concentrations of more volatile compounds (e.g., hexachlorobenzene, PCB-28 and -52) than skuas. Regional differences in penguin pre-breeding foraging areas did not significantly affect their POP burdens, whereas the trans-equatorial migration and foraging sites of skuas were strongly reflected in their pollutant profiles, especially for PBDEs and DPs. Overall, our results provide new insights on migratory birds as biovectors of POPs, including non-globally regulated compounds such as DP, from northern regions to Antarctica.

Organochlorine contaminants in the muscle, liver and brain of seabirds (Larus) from the coastal area of the Southern Baltic

The presence of persistent organic pollutants in the environment manifests itself most strongly in the marine trophic chain, where the highest link is comprised of seabirds. At the same time, seabirds are excellent indicators of contamination in their habitat. The present study concentrates on toxic substances: polychlorinated dibenzo-p-dioxin (PCDDs), polychlorinated dibenzofurans (PCDFs) and chlorinated organic pesticides (OCPs) accumulated in the livers, pectoral muscles and brains of dead gulls collected along the Polish coast of the Baltic Sea in the years 2010-12. The highest toxic equivalence was determined in the livers of Larus argentatus (TEQ(birds TEF)-28.3pgg(-1) ww) and Larus marinus (TEQ(birds TEF)-29.9pgg(-1) ww.). However, the toxic equivalence of muscles was lower and amounted to 3.9pgg(-1) ww. and 7.8pgg(-1) ww. respectively for the two species. The lowest toxic equivalence was found in the brains of birds, where only one, the most toxic, 2,3,7,8 TCDD congener was found (TEQ(birds TEF) 0.87pgg(-1) ww). The highest concentration of chloroorganic pesticides was determined in the brains of the birds (total OCP 167.8pgg(-1) ww.), lower concentrations were found in the livers (total OCP 92.1pgg(-1) ww.) and muscles (total OCP 43.1pgg(-1) ww.). With regard to pesticides, the highest proportion in the total OCP content was constituted by DDT and its isomers (liver 81%, muscles 77% and brain 55%). High concentrations of the studied pollutants in the livers of gulls found dead on the coast of the Southern Baltic could have been effected by levels of contamination in the birds' last meals, which resulted in a seven-fold increase of the liver's toxic equivalence and a two-fold increase in OCP concentration in relation to muscles.

Persistent organic pollutants and inorganic elements in the Balearic shearwater Puffinus mauretanicus wintering off Portugal

This study presents the first data on trace element and organic pollutant concentrations in the Critically Endangered Balearic shearwater Puffinus mauretanicus collected in 2010 and 2011 in Portugal. Trace element levels were below the threshold levels for adverse effects on birds, despite the Hg concentrations in feathers (4.35μg·g-1ww). No significant differences were detected between individuals from 2010 and 2011 except for Se concentrations in liver, feathers and muscle (higher in 2010) and Ag in liver and muscle (higher in 2011). No significant differences were detected in total concentrations of organochlorine compounds in Balearic shearwaters between years, although PCB congeners -101 and -180 presented higher concentrations in individuals from 2010. The PCB congeners -138, -153 and -180, and 4.4-DDE were detected in all individuals. This study on toxic elements and organic pollutants in wintering Balearic shearwaters provides baseline data from which deviations can be detected in the future.

Temporal trends of mercury, organochlorines and PCBs in northern gannet (Morus bassanus) eggs from Bonaventure Island, Gulf of St. Lawrence, 1969-2009

Since 1969, northern gannet (Morus bassanus) eggs from Bonaventure Island, Québec, have been collected to monitor concentrations of contaminants. Levels of p,p'-DDE, which caused low breeding success of Bonaventure gannets in the 1960s, decreased by 99.4% from 1969 to 2009 (17.1-0.1 mg/kg ww), with concomitant improvement of hatching success. PCBs, most organochlorines and mercury also showed decreasing trends. Stable isotopes of carbon (δ(13)C) and nitrogen (δ(15)N) were measured to track the possible influence of diet changes on concentrations of contaminants over time. The confounding effect of the combustion of fossil fuels on baseline values of δ(13)C (the Suess effect) was taken into account. No temporal trends were observed in δ(13)C and δ(15)N values in gannet eggs. Hence trophic level or foraging area had a negligible influence on temporal trends of contaminants.

Identifying the provenance of Leach's storm petrels in the North Atlantic using polychlorinated biphenyl signatures derived from comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry

PCB signatures can be used for source identification, exposure studies, age dating and bio-monitoring. This study uses comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-ToFMS) to produce a PCB signature comprised of over 80 PCBs for individual Leach's storm petrels (Oceanodroma leucorhoa). The Leach's storm petrel is a relatively small, elusive, understudied pelagic bird, which only returns to remote islands under darkness during the breeding season. Samples were obtained from 25 Leach's storm petrels found dead in Canada and the UK following storm events in 2006 and 2009. Tissue samples were extracted and analysed by GCxGC-ToFMS and results showed that 83 PCB congeners were present in >60% of samples. An assessment of the PCB signature in four different tissue types showed that it did not vary greatly in samples obtained from the gut, heart, liver and stomach. Multivariate statistical analysis identified a distinctive PCB signature in birds from Canada and Europe which was used to identify the regional provenance and transatlantic movement of individual birds. The findings showcase the ability of GCxGC-ToFMS to provide the high quality congener specific analysis that is necessary for PCB fingerprinting, as well as highlighting the potential of PCB signatures for use in ecological studies of movement, foraging and behaviour.