Deer as sentinels of emerging environmental pollution: Assessing contamination patterns and seasonal variations

Environmental pollution caused by various chemicals is a pressing issue that affects every ecosystem. National parks play a special role in protecting and preserving nature. However, despite their special status as protected areas, they are not immune to environmental pollution. We assessed the pollution burden of ungulate populations in eight national parks from all over Germany. We analyzed 118 compounds from eight pollutant groups (indicators for anthropogenic pollution, active pharmaceutical ingredients (APIs), polycyclic aromatic hydrocarbons (PAHs), personal care product ingredients (PCPs), pesticides, plasticizers, persistent organic pollutants (POPs), and industrial chemicals) in a total of 442 liver samples from Cervus elaphus and Dama dama taken between October 2023 and January 2025. Results revealed the presence of 61 different analytes in the samples. Parallel detected analytes in samples ranged from 14 to 33, (median 18). APIs and pesticides went largely undetected, whilst contamination with PAHs and PCPs was comparable among all eight parks and three age groups (fawn, subadult and adult). We are the first to report on such a wide range of specific compounds in ungulates, particularly emerging groups of pollutants. Determined concentrations of anthropogenic pollutants, industrial chemicals, plasticizers and POPs differed between parks. Statistical analyses and regression model fitting provided no evidence of seasonal variation in the contamination with anthropogenic pollutants, industrial chemicals, PAHs and POPs. The high number of analytes detected in parallel is alarming in terms of potential cocktail effects and underlines the importance of sustainable management of environmental pollution and further research into emerging pollutants.