A preliminary study on the detection of potential contaminants in the European brown hare (Lepus europaeus) by suspect and microplastics screening

•Specimens of free-ranging European brown hares from Germany and Austria as well as indoor controls were monitored for exposure to chemicals and microplastics.•In plasma, residues of polyethoxylated tallow amines and propylparaben were observed.•Polyethoxylated tallow amine exposure might be linked with intake of agrochemicals.•Microplastics were found in faeces and intestine samples from free-ranging hares and indoor control hares.•Numerous microplastic particles made of chlorinated polyethylene were detected in the lymph nodes of one of the wild hares from Pellworm. The European brown hare (Lepus europaeus) is an herbivorous mammal of high ecological impact, which is widespread throughout Europe. Despite its ability to adapt to varying habitat conditions, this species has experienced a decline in numbers since the 1960s. Pathological examinations of dead individuals from different geographical regions have shown that most animals suffer from intestinal inflammation with changes in the intestinal mucosa resulting in diarrhoea and death. Nevertheless, even after years of extensive research the underlying factors causing observed pathological changes are still unknown. As wild animals are living in diverse environments, it was speculated that complex interactions of multiple factors, including exposure to chemicals and microplastics, may be involved. This pilot study was aimed to provide evidence for the occurrence of environmental contaminants in body fluids, tissues and faces of wild brown hares from Pellworm/Germany and Lower Austria/Austria, as well as of indoor control hares from Vienna/Austria. In this preliminary study, suspect and microplastics screening approaches were applied. Suspect screening, employing liquid chromatography-tandem mass spectrometry, enabled the identification of polyethoxylated tallow amines (POEAs), N-lauroylsarcosine, propylparaben and trinexapac in plasma samples. Interestingly, POEAs had only been found in the wild hares investigated. This detection may indicate exposure to agrochemicals. With microplastics screening, a low number of particles corresponding to six commonly used types of plastic were detected in faeces and intestinal samples. Remarkable, numerous microplastic particles were detected in the lymph nodes of one wild brown hare from Pellworm. No significant differences in microplastics exposure between wild hares and indoor controls were observed. To our knowledge, this is the first study that applied a suspect