Hydrological outlook UK - March 2017

Ecology and Environment

NERC/centre for Ecology & Hydrology

关键词: rodenticide;    barn owl;    difenacoum;    bromadiolone;    brodifacoum;   

英国|英语

来源: NERC Open Research Archive

【 摘 要 】

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 exposedto Second Generation Anticoagulant Rodenticides (SGARs). The barn owl Tyto alba is a sentinel forspecies that are generalist predators of small mammals in rural areas in the UK and monitoring of liverSGAR residues in barn owls has been adopted as an element of the monitoring undertaken as part ofanticoagulant rodenticide stewardship. Monitoring of liver SGAR residues in some 100 barn owls peryear is conducted in support of stewardship and annually collected data are compared with those from395 barn owls that died between 2006 and 2012 (hereafter termed baseline years), prior to the 2016changes 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 abaseline was that all measurements had been made using the same analytical techniques, there hadbeen 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 werebromadiolone, difenacoum and brodifacoum. Overall, 90% of the owls had detectable liver residues ofone or more SGAR.The metrics to be used for stewardship monitoring are reported below in terms of differences betweenowls that died in 2017 and in baseline years.飩?Numbers of barn owls containing detectable residues of flocoumafen and difethialone.There was no significant difference in the proportion of barn owls with detectable liverresidues of either flocoumafen or difethialone between the baseline years and 2017.飩?The ratio of birds with 鈥漧ow鈥?(<100 ng/g wet wt.) vs 鈥渉igh鈥?(>100 ng/g wet wt.)concentrations for any single SGAR or for 鈭慡GARs. There was no significant differencebetween barn owls from baseline years and from 2017 for any individual compound orfor summed SGARs (鈭慡GARs)飩?Average concentrations of brodifacoum, difenacoum, bromadiolone and 鈭慡GARs in thecohort of owls with 鈥渓ow鈥?residues (<100 ng/g wet wt.) and 鈥渉igh鈥?residues (>100 ng/gwet wt.). There was no significant difference between barn owls from baseline years andfrom 2017 in the concentrations of either 鈥渓ow鈥?or 鈥渉igh鈥?residues for bromadiolone,difenacoum and brodifacoum, or for all residues summed (鈭慡GARs). Although notstatistically significant, the median and 75th percentile values of 鈥渓ow residues鈥?of mostcompounds and 鈭慡GARs were lower in 2017 [and 2016] than in the baseline yearsOverall, the lack of statistically significant differences in SGAR accumulation by barn owls in 2017compared within baseline years suggests that full implementation of stewardship since 2016 has yetto be reflected by a detectable general reduction in exposure of barn owls.