Constitutive changes in pigment concentrations: implications for estimating isoprene emissions using the photochemical reflectance index

The photochemical reflectance index (PRI), through its relationship with light use efficiency (LUE) and xanthophyll cycle activity, has recently been shown to hold potential for tracking isoprene emissions from vegetation. However, both PRI and isoprene emissions can also be influenced by changes in carotenoid pigment concentrations. Xanthophyll cycle activity and changes in carotenoid concentrations operate over different timescales but the importance of constitutive changes in pigment concentrations for accurately estimating isoprene emissions using PRI is unknown. To clarify the physiological mechanisms behind the PRI–isoprene relationship, the light environment of potted Salix viminalis (dwarf willow) trees was modified to induce acclimation in photosynthetic rates, phytopigments, isoprene emissions and PRI. Acclimation resulted in differences in pigment concentrations, isoprene emissions and PRI. Constitutive changes in carotenoid concentration were significantly correlated with both isoprene emissions and PRI, suggesting that the relationship between PRI and isoprene emissions is significantly influenced by constitutive pigment changes. Consequently knowledge regarding how isoprene emissions are affected by both longer term changes in total carotenoid concentrations and shorter term dynamic adjustments of LUE is required to facilitate interpretation of PRI for monitoring isoprene emissions

Second generation anticoagulant rodenticide residues in barn owls 2018

The current report is the fourth in a series of annual reports that describe the monitoring of second generation anticoagulant rodenticide (SGAR) liver residues in barn owls Tyto alba in Britain. This work is an element of an overarching monitoring programme undertaken to track the outcomes of stewardship activities associated with the use of anticoagulant rodenticides. The barn owl is used for exposure monitoring as it is considered a sentinel for species that are generalist predators of small mammals in rural areas. The specific work reported here is the measurement of liver SGAR residues in 100 barn owls that died in 2018 in locations across Britain. The residue data are compared with those from 395 barn owls that died between 2006 and 2012 (hereafter termed baseline years), prior to changes in anticoagulant rodenticide (AR) authorisations and onset of stewardship. As in the baseline years, the compounds detected most frequently in barn owls that died in 2018 were bromadiolone, difenacoum and brodifacoum. Overall, 87% of the owls had detectable liver residues of one or more SGAR. The metrics to be used for stewardship monitoring are reported below in terms of differences between owls that died in 2018 and in baseline years. Numbers of barn owls containing detectable residues of flocoumafen and difethialone. There was no significant difference in the proportion of barn owls with detectable liver residues of flocoumafen between the baseline years and 2018. There was a significantly higher proportion of barn owls with detectable liver residues of difethialone in 2018 compared to baseline years (8% vs 0.3% ). The ratio of birds with ”low” (100 ng/g wet wt.) concentrations for any single SGAR or for ∑SGARs. There was no significant difference between barn owls from baseline years and from 2018 for any individual compound or for summed SGARs (∑SGARs), although a decrease in the proportion of birds with “high” difenacoum residues approached significance. Average concentrations of brodifacoum, difenacoum, bromadiolone and ∑SGARs in the cohort of owls with “low” residues (100 ng/g ww). There was no significant difference between barn owls from baseline years and from 2018 in the concentrations of either “low” or “high” residues for bromadiolone, difenacoum (data tested statistically only for “low residues”), all residues summed (∑SGARs), or “high” brodifacoum residues. The median concentration of “low” brodifacoum residues was higher in birds from 2018 than in baseline years. Overall, there were few differences in liver SGAR accumulation between barn owls that died in baseline years and in 2018. The lack of significant reductions in SGAR residues in barn owls in 2018 suggests that full implementation of stewardship since 2016 has yet to result in a reduction in exposure of barn owls to SGARs

From seeds to plasma : confirmed exposure of multiple farmland bird species to clothianidin during sowing of winter cereals

Neonicotinoids are the largest group of systemic insecticides worldwide and are most commonly applied as agricultural seed treatments. However, little is known about the extent to which farmland birds are exposed to these compounds during standard agricultural practices. This study uses winter cereal, treated with the neonicotinoid clothianidin, as a test system to examine patterns of exposure in farmland birds during a typical sowing period. The availability of neonicotinoid-treated seed was recorded post-sowing at 39 fields (25 farms), and camera traps were used to monitor seed consumption by wild birds in situ. The concentration of clothianidin in treated seeds and crop seedlings was measured via liquid chromatography-tandem mass spectrometry, and avian blood samples were collected from 11 species of farmland bird from a further six capture sites to quantify the prevalence and level of clothianidin exposure associated with seed treatments. Neonicotinoid-treated seeds were found on the soil surface at all but one of the fields surveyed at an average density of 2.8 seeds/m2. The concentration of clothianidin in seeds varied around the target application rate, whilst crop seedlings contained on average 5.9% of the clothianidin measured in seeds. Exposure was confirmed in 32% of bird species observed in treated fields and 50% of individual birds post-sowing; the median concentration recorded in positive samples was 12 ng/mL. Results here provide clear evidence that a variety of farmland birds are subject to neonicotinoid exposure following normal agricultural sowing of neonicotinoid-treated cereal seed. Furthermore, the widespread availability of seeds at the soil surface was identified as a primary source of exposure. Overall, these data are likely to have global implications for bird species and current agricultural policies where neonicotinoids are in use, and may be pertinent to any future risk assessments for systemic insecticide seed treatments

How dо pesticides get into honey?

Honey is nature’s sweetest gift. But did you know that honey may contain pesticides? Farmers use pesticides to kill pests that harm their crops. But pesticides also hurt honey bees and other beneficial insects. Furthermore, when bees collect nectar from flowers which received pesticide treatments, these chemicals make their way into the honey. In the past, scientists found neonicotinoids (a class of pesticides) in about half of the honey samples collected in the United Kingdom. Since 2014, the European Union banned neonicotinoids in flowering crops that bees visit. We wanted to know how effective this policy was. Does UK honey still contain neonicotinoids? Here, we collected and tested honey samples from beekeepers across the UK. We found that about a fifth of all honey contained neonicotinoids. These chemicals are not at dangerous levels for human health but may harm the bees in the long run

Detecting fluoxetine and norfluoxetine in wild bird tissues and feathers

The contamination of the environment with human pharmaceuticals is widespread and demand for such products is mounting globally. Wild vertebrates may be at particular risk from any effects from pharmaceuticals, because of the evolutionary conservation of drug targets. However, exposure of wildlife to pharmaceuticals is poorly characterised, partly due to challenges associated with detecting rapidly metabolised compounds. As part of a wider study on the behavioural effects of fluoxetine (Prozac) on Eurasian starlings (Sturnus vulgaris), we investigated which avian samples are best suited for detecting exposure to fluoxetine in free-living birds. We analysed plasma, various tissues and tail feathers (grown both in the wild and in captivity during the dosing period) from fluoxetine-treated birds (dosed daily with 0.035 mg kg-1 bodyweight for 28 weeks), and liver tissue and tail feathers from sham-dosed birds. We detected fluoxetine in only two of twelve plasma samples from dosed birds. In dosed birds, median concentrations of free fluoxetine/norfluoxetine in tissues (two hour post-final dose) were: 111.2/67.6 ng g-1 in liver, 29.6/5.7 ng g-1 in kidney, 14.2/4.0 ng g-1 in lung, 15.1/1.6 ng g-1 in brain. We estimated that fluoxetine would remain detectable in liver and kidney approximately 4.5 times longer (90 h) than in brain (20h). In dosed birds, fluoxetine was detected in feathers regrown during the dosing period (median concentration = 11.4 ng g-1) at concentrations significantly higher than in regrown feathers from control birds. Fluoxetine residues were detected in wild-grown feathers (grown before the birds were brought into captivity) at concentrations up to 27.0 ng g-1, providing some evidence of likely exposure in the wild. Our results show liver and kidney can be used for detecting fluoxetine in avian carcasses and provide a first indication that feathers may be useful for assessing exposure to fluoxetine, and possibly other pharmaceuticals

Second generation anticoagulant rodenticide residues in barn owls 2016

CEH contract report to the Campaign for Responsible Rodenticide Use (CRRU) UK

Neonicotinoid residues in UK honey despite European Union moratorium

Due to concerns over negative impacts on insect pollinators, the European Union has implemented a moratorium on the use of three neonicotinoid pesticide seed dressings for mass-flowering crops. We assessed the effectiveness of this policy in reducing the exposure risk to honeybees by collecting 130 samples of honey from bee keepers across the UK before (2014: N = 21) and after the moratorium was in effect (2015: N = 109). Neonicotinoids were present in about half of the honey samples taken before the moratorium, and they were present in over a fifth of honey samples following the moratorium. Clothianidin was the most frequently detected neonicotinoid. Neonicotinoid concentrations declined from May to September in the year following the ban. However, the majority of post-moratorium neonicotinoid residues were from honey harvested early in the year, coinciding with oilseed rape flowering. Neonicotinoid concentrations were correlated with the area of oilseed rape surrounding the hive location. These results suggest mass flowering crops may contain neonicotinoid residues where they have been grown on soils contaminated by previously seed treated crops. This may include winter seed treatments applied to cereals that are currently exempt from EU restrictions. Although concentrations of neonicotinoids were low (<2.0 ng g-1), and posed no risk to human health, they may represent a continued risk to honeybees through long-term chronic exposure

Second generation anticoagulant rodenticide residues in barn owls 2017

CEH contract report to the Campaign for Responsible Rodenticide Use (CRRU) UK. A wide range of avian and mammalian predators and scavengers in rural Britain is known to be exposed to Second Generation Anticoagulant Rodenticides (SGARs). The barn owl Tyto alba is a sentinel for species that are generalist predators of small mammals in rural areas in the UK and monitoring of liver SGAR residues in barn owls has been adopted as an element of the monitoring undertaken as part of anticoagulant rodenticide stewardship. Monitoring of liver SGAR residues in some 100 barn owls per year is conducted in support of stewardship and annually collected data are compared with those from 395 barn owls that died between 2006 and 2012 (hereafter termed baseline years), prior to the 2016 changes in anticoagulant rodenticide (AR) authorisations and onset of stewardship. The rationale for using data on SGAR residues in barn owls that died between 2006 and 2012 as a baseline was that all measurements had been made using the same analytical techniques, there had been little clear change in exposure over that time period, and the data were the most recent available. The aim of the current study was to measure SGAR exposure in barn owls in 2017. As in the baseline years, the compounds detected most frequently in barn owls that died in 2017 were bromadiolone, difenacoum and brodifacoum. Overall, 90% of the owls had detectable liver residues of one or more SGAR. The metrics to be used for stewardship monitoring are reported below in terms of differences between owls that died in 2017 and in baseline years. Numbers of barn owls containing detectable residues of flocoumafen and difethialone. There was no significant difference in the proportion of barn owls with detectable liver residues of either flocoumafen or difethialone between the baseline years and 2017. The ratio of birds with ”low” (100 ng/g wet wt.) concentrations for any single SGAR or for ∑SGARs. There was no significant difference between barn owls from baseline years and from 2017 for any individual compound or for summed SGARs (∑SGARs) Average concentrations of brodifacoum, difenacoum, bromadiolone and ∑SGARs in the cohort of owls with “low” residues (100 ng/g wet wt.). There was no significant difference between barn owls from baseline years and from 2017 in the concentrations of either “low” or “high” residues for bromadiolone, difenacoum and brodifacoum, or for all residues summed (∑SGARs). Although not statistically significant, the median and 75th percentile values of “low residues” of most compounds and ∑SGARs were lower in 2017 [and 2016] than in the baseline years Overall, the lack of statistically significant differences in SGAR accumulation by barn owls in 2017 compared within baseline years suggests that full implementation of stewardship since 2016 has yet to be reflected by a detectable general reduction in exposure of barn owls

Second generation anticoagulant rodenticide residues in barn owls 2019

The fifth in a series of annual reports describing the magnitude of second generation anticoagulant rodenticide (SGAR) liver residues in barn owls Tyto alba in Britain

Second generation anticoagulant rodenticide residues in barn owls 2020

The current report is the sixth in a series of annual reports that describe the monitoring of second generation anticoagulant rodenticide (SGAR) liver residues in barn owls Tyto alba in Britain. This work is an element of an overarching monitoring programme undertaken to track the outcomes of stewardship activities associated with the use of anticoagulant rodenticides. The barn owl is used for exposure monitoring as it is considered a sentinel for species that are generalist predators of small mammals in rural areas. The specific work reported here is the measurement of liver SGAR residues in 100 barn owls that died in 2020 at locations across Britain. The residue data are compared with those from 395 barn owls that died between 2006 and 2012 (hereafter termed baseline years), prior to changes in anticoagulant rodenticide (AR) authorisations and onset of stewardship. As in the baseline years, the compounds detected most frequently in barn owls that died in 2020 were brodifacoum, bromadiolone, and difenacoum. Overall, 88% of the owls had detectable liver residues of one or more SGAR. Numbers of barn owls containing detectable residues of flocoumafen and difethialone. There was no significant difference in the proportion of barn owls with detectable liver residues of flocoumafen between the baseline years and 2020. There was a significantly higher proportion of barn owls with detectable liver residues of difethialone in 2020 compared to baseline years (5% vs 0.3%) but it was lower than in some of the intervening years (2016-2019). The ratio of birds with “low” (100 ng/g wet wt.) concentrations for any single SGAR or for ∑SGARs. There were significantly higher proportion of birds from 2020 with “high” concentrations of brodifacoum and summed SGARs (ƩSGARs) detected in their livers compared to baseline years. Average concentrations of brodifacoum, difenacoum, bromadiolone and ∑SGARs in the cohort of owls with “low” residues (100 ng/g wet wt.). There was no significant difference between barn owls from baseline years and from 2020 in the concentrations of either “low” or “high” residues for all residues summed (∑SGARs), bromadiolone and difenacoum, or “high” brodifacoum residues. The median concentration of “low” brodifacoum residues was higher in birds from 2020 than in baseline years. Overall, there were few differences in liver SGAR accumulation between barn owls that died in baseline years and in 2020, the eception being a potential increase brodifacoum residues. The lack of significant reductions in SGAR residues in barn owls in 2020 suggests that full implementation of stewardship since 2018 has yet to result in a statistically significant reduction in exposure of barn owls to SGARs