Advancing One Health surveillance with non-invasive biomonitoring: a review of persistent pesticide exposure assessment using external keratinized animal tissue

Despite less use today, persistent pesticides remain ubiquitous in the environment, and exposure presents risks for humans, animals, and ecosystems. Biomonitoring persistent pesticides in animals can provide critical information for evaluating shared exposures and risks, information which is currently lacking in One Health surveillance systems. One promising non-invasive option is the use of animal external keratinized tissue. The goal of this review is to examine and summarize the current state of research on the use of external keratinized animal tissues for assessing exposure to persistent pesticides. Six databases were searched for articles published between 1950 and 2024 related to the detection of persistent pesticides in animal feathers, hair, and other keratinized tissues. Articles were screened for inclusion, and information such as order, species, sample matrix, country of origin, and methods were summarized. A total of 31 articles were included in this review. Articles were published between 2001 and 2021, and most measured DDT in bird feathers. Feathers most commonly came from live birds in the Strigiformes, Passeriformes, and Falconiformes orders. Carnivorous animals were the most well-studied. The majority of studies used liquid-based phase extraction and gas chromatography-mass spectrometry. Over half of the studies were conducted in European countries. Feathers from apex predators such as those in the Strigiformes, Passeriformes, and Falconiformes orders offer a particular advantage because these birds are especially vulnerable due to their long lifespan, and they also typically have extensive migration patterns and are primarily carnivorous with high trophic levels that account for bioaccumulation and biomagnification. The feathers are also large in size and sampling collection is relatively easy. However, the determination of appropriate species and feather type for analysis is complex, as diet, breeding habits, migration patterns, and molting must be considered. The use of feathers and hair from animals for non-invasive biomonitoring of persistent pesticides can offer important information on shared animal, human, and environmental exposures. Although not yet widely implemented, using feathers from apex predators to measure persistent pesticides in animals is becoming more prevalent and is a promising tool for One Health surveillance.