Persistent Organic Pollutants (POPs) and inorganic elements in predatory bird livers and eggs 2007 to 2009: a Predatory Bird Monitoring Scheme (PBMS) Report

The Predatory Bird Monitoring Scheme (PBMS; http://pbms.ceh.ac.uk/) is the umbrella project that encompasses the Centre for Ecology & Hydrology’s National Capability contaminant monitoring and surveillance work on avian predators. By monitoring sentinel vertebrate species, the PBMS aims to detect and quantify current and emerging chemical threats to the environment and in particular to vertebrate wildlife. Sparrowhawk livers were analysed for a range of persistent organic pollutants (POPs) and heavy metals. Sparrowhawks are studied because they have a wide distribution across the Britain and can be used as a sentinel species for the terrestrial environment. Mean PCB and mercury liver concentrations were below those thought to have an adverse effect on individual birds. Pollutants, such as mercury and PCBs, can affect development and hatchability. Therefore, the PBMS also monitors the levels of contaminants in the eggs of a range of species including those of conservation concern, such as golden eagle and the re-introduced white-tailed sea eagle. Other species that are monitored are the northern gannet, which is used as a monitor of the marine environment, and merlin that hunts in upland habitats. The residues measured in the eggs of golden eagle and gannets collected between 2007 and 2009 were below those thought to have an adverse effect, but some residues in individual merlin eggs were above concentrations suggested to be indicative of no effect concentrations for birds generally. Few white-tailed see eagle eggs are received for analysis by the PBMS but many of the eggs that have been analysed, including one of the eggs analysed for this report, have DDE, PCB and/or mercury concentrations above levels associated with adverse effects on bird embryos and hatching success. In terms of long-term trends, there has been a decline in congener sum PCB contamination in the eggs of most of the species that have been monitored, except for coastal nesting golden eagles. In contrast however, there has been no significant decline over time in PCB concentrations in sparrowhawk livers and concentrations of ‘Paris 10’ congener sum and PCB-TEQ concentrations have also largely remained unchanged in both livers and eggs since monitoring began in 1996. Evidence for changes over time in mercury concentrations in predatory birds or their eggs is inconsistent across the species monitored. Where a decline has been detected, it has occurred before approximately 1990 and remained largely unchanged since then

Lead (Pb) concentrations in predatory bird livers 2010 and 2011: a Predatory Bird Monitoring Scheme (PBMS) report

The Predatory Bird Monitoring Scheme (PBMS; http://pbms.ceh.ac.uk/) is the umbrella project that encompasses the Centre for Ecology & Hydrology’s National Capability contaminant monitoring and surveillance work on avian predators. By monitoring sentinel vertebrate species, the PBMS aims to detect and quantify current and emerging chemical threats to the environment and in particular to vertebrate wildlife. Lead (Pb) is a highly toxic metal that acts as a non-specific poison affecting all body systems and has no known biological requirement. Sources of Pb in the environment include lead mining, the refining and smelting of lead and other metals, the manufacture and use of alkyl lead fuel additives, and the use of lead ammunition. The present study is the first two years of a PBMS monitoring programme to quantify the scale of exposure to [and associated risk from] Pb in predatory birds. The aim is to quantify the extent of exposure to lead [as assessed from liver residues] in two predatory bird species, the red kite (Mivus milvus) and the sparrowhawk (Accipiter nisus). The red kite is a scavenger and, as such, is particularly at risk from consumption of Pb ammunition in unretrieved game. Sparrowhawks prey predominantly upon live passerine birds that are unlikely to be shot in the UK; likely sources of exposure are diffuse Pb contamination although some individuals may also be exposed to Pb particles ingested by their prey. We also examined the liver Pb isotope ratios in to explore whether they can be used to ascribe likely sources of any Pb detected in the birds. Red kites had significantly higher Pb concentration than those measured in sparrowhawks but the majority of sparrowhawks and all the red kites had liver Pb concentrations below those thought to cause clinical and sub-clinical adverse effects in Falconiforme species. There was overlap in the liver Pb isotope ratios of red kites and sparrowhawks yet there was evidence of separation between the two species. There was also evidence of overlap with the isotope signature for coal and for Pb shot but the isotope signatures in the bird livers were distinct from that of petrol Pb. The Pb isotope pattern observed in the red kites and sparrowhawks in the current study may reflect the fact that liver Pb concentrations were low in the small sample of birds that were analysed and may have been a result of exposure to low-level, diffuse contamination.birds. Red kites had significantly higher Pb concentration than those measured in sparrowhawks but the majority of sparrowhawks and all the red kites had liver Pb concentrations below those thought to cause clinical and sub-clinical adverse effects in Falconiforme species. There was overlap in the liver Pb isotope ratios of red kites and sparrowhawks yet there was evidence of separation between the two species. There was also evidence of overlap with the isotope signature for coal and for Pb shot but the isotope signatures in the bird livers were distinct from that of petrol Pb. The Pb isotope pattern observed in the red kites and sparrowhawks in the current study may reflect the fact that liver Pb concentrations were low in the small sample of birds that were analysed and may have been a result of exposure to low-level, diffuse contamination

PBMS archive holdings: a Predatory Bird Monitoring Scheme (PBMS) report

The Predatory Bird Monitoring Scheme (PBMS; http://pbms.ceh.ac.uk/) is the umbrella project that encompasses the Centre for Ecology & Hydrology’s National Capability contaminant monitoring and surveillance work on avian predators. By monitoring sentinel vertebrate species, the PBMS aims to detect and quantify current and emerging chemical threats to the environment and in particular to vertebrate wildlife. As part of its chemical monitoring studies the PBMS receives and carries out post-mortem examinations on approximately 300 birds or prey each year. A range of tissues are taken from the carcasses. Around 100 addled and deserted eggs from various species are also submitted to the PBMS. The eggs are cracked open and the contents collected. The shells are retained for two years prior to being donated to the National Museums Scotland for cataloguing and archiving. The main purpose for collecting tissues and egg contents is for use in annual monitoring of pollutant concentrations by the PBMS. However, not all samples are used each year for chemical analyses and, even when samples are used, typically only a sub-sample is analysed. Samples that are not analysed or for which only a sub-sample is analysed are retained in the PBMS archive. Overall, the number of samples in the PBMS archive is approaching 50,000 tissue and egg content samples. The material in the archive is used for research studies investigating chemical fate and behaviour, to trial new monitoring, and for a wide range of other studies, some of which are unrelated to pollutants. The purpose of this short report is to summarise the main holdings in the PBMS archive. This is done for the seven species for which we currently or used to obtain relatively large numbers of carcasses. We also draw attention to holdings of a small number of other species which may be of priority conservation concern. The information is broken down by type of sample that is held, the decade in which it was collected, and provenance as to whether samples were from England and Wales, or Scotland. In addition to information on numbers of samples from carcasses, we provide a description on the holdings for the number of egg contents for various species, again broken down by decade and provenance

Concentrations of perfluorinated compounds (PFCs) in northern gannet, Morus bassanus, eggs: a Predatory Bird Monitoring Scheme (PBMS) report

The Predatory Bird Monitoring Scheme (PBMS; http://pbms.ceh.ac.uk/) is the umbrella project that encompasses the Centre for Ecology & Hydrology’s National Capability contaminant monitoring and surveillance work on avian predators. By monitoring sentinel vertebrate species, the PBMS aims to detect and quantify current and emerging chemical threats to the environment and in particular to vertebrate wildlife. This report presents the results of a pilot study to quantify the concentrations of perfluorinated compounds (PFCs) in the eggs of the northern gannet, Morus bassanus, from the Ailsa Craig and Bass Rock colonies off the UK coast. The principle aim of this work determine the concentrations of PFCs that are accumulated in the eggs of gannets and whether there was any evidence of differences in accumulation between eggs from the two colonies studied. The egg contents were analysed by Liquid Chromatograph – Mass Spectrometry (LC-MS) techniques. Compounds from both the perfluorinated carboxylate and perfluorinated sulfonate groups of PFCs were quantified. PFCs were detected in all of the ten eggs analysed, with both carboxylate and sulfonate compounds present. Perfluorobutanoate (PFBA) and perfluorononanoate (PFNA) concentrations were both significantly higher in eggs from Ailsa Craig compared to those from Bass Rock but there was no difference between colonies in egg concentrations of sum PFC, sum carboxylate or sum sulphonate concengtrations. Overall data from this limited one year of sampling suggests that gannet eggs from both Ailsa Craig and Bass Rock contain relatively low concentrations compared to eggs from some other species that have been examined. Concentrations of perfluorooctane sulfonate (PFOS) were with an order of magnitude of residues associated with adverse effects [and for one egg from Bass Rock these levels were exceeded] but the majority of eggs from both colonies contained PFOS residues that exceeded a suggested predicted no effect concentration (PNEC) for this compound

Anticoagulant rodenticides in predatory birds 2012: a Predatory Bird Monitoring Scheme (PBMS) report

The Predatory Bird Monitoring Scheme (PBMS; http://pbms.ceh.ac.uk/) is the umbrella project that encompasses the Centre for Ecology & Hydrology’s National Capability contaminant monitoring and surveillance work on avian predators. By monitoring sentinel vertebrate species, the PBMS aims to detect and quantify current and emerging chemical threats to the environment and in particular to vertebrate wildlife. Anticoagulant rodenticides, and in particular second generation anticoagulant rodenticides (SGARs), can be toxic to all mammals and birds. Predators that feed upon rodents are particularly likely to be exposed to these compounds. The PBMS, together with other studies, has shown that there is widespread exposure to SGARs of a diverse range of predators in Britain and that some mortalities occur as a result. This report describes the PBMS monitoring for SGARs in barn owls (Tyto alba) found dead in 2012, summarises long term trends in exposure in this species, and compares the relative prevalence of SGARs in barn owls in England and Scotland. We also report the results of an initial investigation into SGAR contamination in 42 sparrowhawks (Accipiter nisus) found dead between 2010 and 2012. Sparrowhawks normally feed on birds and the aim of this investigation was to assess the potential importance of avian foodwebs in exposure of predators to SGARs. SGARs were detected in 87% of the 63 barn owls that were collected in 2012. The most prevalent compounds were difenacoum, bromadiolone and brodifacoum. The majority of the residues were low (< 0.1 µg/g wet weight). One owl was diagnosed as likely to have been poisoned by SGARs. Most of the sparrowhawk livers that were analysed had detectable liver SGAR concentrations, again mainly difenacoum, bromadiolone and brodifacoum (79%, 55% and 64% of birds, respectively). The proportion of sparrowhawks with detectable residues of one or more SGAR (93%) did not differ significantly from that for barn owls (86%) collected over the same time 2010-12 time period. Co-occurrence of multiple residues in the liver was common in barn owls and sparrowhawks (70% and 74% of birds respectively). Sparrowhawks had significantly lower liver sum SGAR concentrations than barn owls in those birds that had detectable residues. SGARs have been monitored in barn owls since 1983. Data on long-term trends have been adjusted to account for changes over time in sensitivity of analytical methods. This has meant that very low residues (<0.025 µg/g wet weight), which are now detectable, are not included in the time trend analysis. Overall, the proportion of both adult and juvenile barn owls with detectable liver concentrations of one or more SGAR has increased significantly over the course of monitoring. The proportion of barn owls with detectable SGAR residues over the period 1990-2012 was two-fold higher in England than in Scotland but residue magnitude did not differ between birds from the two areas

Liver concentrations of flame retardants in Eurasian otters (Lutra lutra) collected from Scotland between 2013 and 2015: a Predatory Bird Monitoring Scheme (PBMS) report

The Predatory Bird Monitoring Scheme (PBMS; http://pbms.ceh.ac.uk/) is the umbrella project that encompasses the Centre for Ecology & Hydrology’s National Capability contaminant monitoring and surveillance work on avian predators. By monitoring sentinel vertebrate species, the PBMS aims to detect and quantify current and emerging chemical threats to the environment and in particular to vertebrate wildlife. The current study presents the results of a study in which the concentrations of polybrominated diphenyl ethers (PBDEs) were determined in the livers of a small sample of Eurasian otters (Lutra lutra) that died in Scotland between 2013 and 2015. The principle aim of this work was to determine the current concentrations of PBDEs that are accumulated by otters in Scotland and whether these concentrations are likely to cause adverse effects in those individuals analysed. The otters that were analysed included adult and sub-adult, males and females although there were insufficient sample numbers to test for differences among these demographic groups. Liver tissue was analysed using Gas Chromatograph – Mass Spectrometry (GC-MS). PBDEs were detected in all otter livers analysed, with congeners BDE47, BDE153 and BDE100 dominant in the congener profile. The toxicological consequences of exposure to PBDEs in otters are uncertain given the lack of established links between liver PBDE concentrations and health effects in this species but concentrations were lower than those associated with adverse effects in mink. The general low levels of PBDEs suggests that there is little evidence to date of toxicologically significant contamination of Scottish otters with these compounds. There is clear evidence that Scottish otters have significantly lower residues of the less-brominated PBDEs than those previously measured in otters from England and Wales. However, these results may not be representative of otters from throughout Scotland as the present sample came predominantly from the Inner Hebrides

Anticoagulant rodenticides in sparrowhawks: a Predatory Bird Monitoring Scheme (PBMS) report

The Predatory Bird Monitoring Scheme (PBMS; http://pbms.ceh.ac.uk/) is the umbrella project that encompasses the Centre for Ecology & Hydrology’s National Capability activities for contaminant monitoring and surveillance work on avian predators. The PBMS aims to detect and quantify current and emerging chemical threats to the environment and in particular to vertebrate wildlife. Second generation anticoagulant rodenticides (SGARs) can be toxic to all mammals and birds. The PBMS together with other studies have shown that in Britain, there is widespread exposure to SGARs in a diverse range of predators of small mammals. Defra’s Wildlife Incident Monitoring Scheme (WIIS) and the PBMS have shown that some mortalities result from this exposure. The main transfer pathway for SGARs has been thought to be most likely via target and non-target rodents that eat SGAR bait. However, recent studies, including a preliminary analysis by the PBMS on sparrowhawks, Accipiter nisus, have suggested that that SGAR transfer through avian transfer pathways may also be important. The aims of the current study were to build on our earlier results by analysing a further 52 sparrowhawks for liver SGAR residues, and using the combined dataset to (i) assess overall levels of exposure in sparrowhawks from across Britain and (ii) determine if age and sex affect the magnitude of liver SGARs residues. A final aim was to compare exposure (assessed from liver residues) in sparrowhawks with that of the barn owl Tyto alba, a predator that takes predominantly small mammals We found one or more SGARs in the livers of 89% of the 94 sparrowhawks we analysed; all birds were collected by the PBMS between 2010 and 2013. A high proportion of these residues were relatively low and none were associated with haemorrhaging unconnected with physical trauma. The proportion of birds with detectable residues and the magnitude of those residues were significantly higher in adults than juveniles, but residues did not vary significantly between males and females. Comparison of liver SGAR residues in barn owls and sparrowhawks that had died over a similar time period indicated that, for both adults and juveniles, sparrowhawks were as likely to have detectable liver SGAR residues as barn owls but the magnitude of the residues was lower in sparrowhawks. Overall this study has demonstrated that food-chain transfer of SGARs can occur via a predominantly avian trophic pathway and lead to secondary exposure

Dilution of individual microtubules observed in real time in vitro: evidence that cap size is small and independent of elongation rate

Although the mechanism of microtubule dynamic instability is thought to involve the hydrolysis of tubulin-bound GTP, the mechanism of GTP hydrolysis and the basis of microtubule stability are controversial. Video microscopy of individual microtubules and dilution protocols were used to examine the size and lifetime of the stabilizing cap. Purified porcine brain tubulin (7-23 microM) was assembled at 37 degrees C onto both ends of isolated sea urchin axoneme fragments in a miniature flow cell to give a 10-fold variation in elongation rate. The tubulin concentration in the region of microtubule growth could be diluted rapidly (by 84% within 3 s of the onset of dilution). Upon perfusion with buffer containing no tubulin, microtubules experienced a catastrophe (conversion from elongation to rapid shortening) within 4-6 s on average after dilution to 16% of the initial concentration, independent of the predilution rate of elongation and length. Based on extrapolation of catastrophe frequency to zero tubulin concentration, the estimated lifetime of the stable cap after infinite dilution was less than 3-4 s for plus and minus ends, much shorter than the approximately 200 s observed at steady state (Walker, R. A., E. T. O'Brien, N. K. Pryer, M. Soboeiro, W. A. Voter, H. P. Erickson, and E. D. Salmon. 1988. J. Cell Biol. 107:1437-1448.). We conclude that during elongation, both plus and minus ends are stabilized by a short region (approximately 200 dimers or less) and that the size of the stable cap is independent of 10-fold variation in elongation rate. These results eliminate models of dynamic instability which predict extensive "build- up" stabilizing caps and support models which constrain the cap to the elongating tip. We propose that the cell may take advantage of such an assembly mechanism by using "catastrophe factors" that can promote frequent catastrophe even at high elongation rates by transiently binding to microtubule ends and briefly inhibiting GTP-tubulin association

Mercury (Hg) concentrations and stable isotope signatures in golden eagle eggs 2009-2013: a Predatory Bird Monitoring Scheme (PBMS) report

The Predatory Bird Monitoring Scheme (PBMS; http://pbms.ceh.ac.uk/) is the umbrella project that encompasses the Centre for Ecology & Hydrology’s National Capability activities for contaminant monitoring and surveillance work on avian predators. The PBMS aims to detect and quantify current and emerging chemical threats to the environment and in particular to vertebrate wildlife. Mercury (Hg) is a neurotoxin and there has been global concern over its impact on humans and wildlife. It has been predicted that global Hg emissions may rise in the future because of increased coal-fired power generation, but, in 2013, the United Nations Environment Programme (UNEP) agreed The Minamata Convention on Mercury, a global treaty to protect human health and the environment from the adverse effects of mercury. An overarching aim of the convention is to control the anthropogenic releases of Hg to the environment. Therefore, long-term trends in environmental Hg concentrations are uncertain. One cost-effective means of assessing such trends is to monitor exposure in sentinel wildlife species. Golden eagles Aquila chrysaetos breed and forage in the Scottish uplands and could prove a sentinel for changing Hg deposition in upland terrestrial areas and associated wildlife exposure. We measured Hg residues in failed golden eagle eggs with the aim of providing baseline data on current levels of exposure. Specifically, we measured Hg concentrations in failed eggs laid between 2009 and 2013 in inland (> 3km from the coast) and coastal (<3 km from the coast) nests. We distinguished nests in this way because coastal nesting birds can feed on seabirds that can accumulate high levels of Hg themselves. Marine dietary Hg inputs could potentially obscure any changes in Hg accumulation associated with altered upland terrestrial Hg deposition, and so we hypothesized that only eggs from inland nests may be useful sentinels. In conjunction with Hg measurements, we examined stable isotope (SI) signatures (carbon (δ13C), nitrogen (δ15N) and sulphur (δ34S)) to determine if they differed between eggs from inland and coastal nests in a manner consistent with feeding primarily on terrestrial and marine prey, respectively. We also examined Hg concentrations and SI signatures of failed white-tailed sea eagle (Haliaeetus albicilla) eggs from nests on the west coast of Scotland. We used these measurements as a comparator against which to assess the extent to which SI and Hg measurements in eggs from coastal golden eagle nests might be indicative of feeding on marine prey and scavenge. We found that SI signatures (particularly δ34S isotopic ratios) and Hg concentrations were similar in golden eagle eggs from coastal nests and white tailed sea eagle eggs. SIs and Hg concentrations in eggs from inland nests were much more variable, and a third had SI signatures that were the same as those of eggs from coastal nests, suggesting that they too were laid by females feeding on a coastal diet. A cluster of seven eggs from inland nests had distinctive δ34S and δ15N values (below 11.0 ‰ and 5.7 ‰ respectively) and it was inferred that these were most likely laid by females feeding terrestrially. Hg concentrations were non-detectable in these seven eggs whereas the median concentration in golden eagle eggs associated with coastal feeding was 0.412 µg/g dry weight, similar to that (0.569 µg/g dry weight) in white tailed sea eagle eggs. Hg concentrations in all eggs were below those thought to be associated with embryotoxic effects. The lack of detectable Hg concentrations in GE eggs associated with upland terrestrial feeding is problematic if these eggs are to be used as sentinels of change in upland Hg concentrations. Re-analysis of a set of eggs using a more sensitive analytical technique may resolve this issue and should be explored, otherwise other sentinels may need to be investigated