Abstract：
Plastic ingestion presents many potential avenues of risk for wildlife. Understanding which species and environments are most exposed to plastic pollution is a critical first step in investigating the One Health implications of plastic exposure. The objectives of this study were the following: 1) Utilize necropsy as part of ongoing passive disease surveillance to investigate ingested mesoplastics in birds collected in Ontario and Nunavut, and examine the relationships between bird-level factors and ingested debris; 2) evaluate microplastic ingestion compared to ingested mesodebris in raptors; and 3) identify potential sentinel species for plastic pollution monitoring in understudied freshwater and terrestrial (inland) environments. Between 2020 and 2022, 457 free-ranging birds across 52 species were received for postmortem examination. The upper gastrointestinal tracts were examined for mesoplastics and other debris (>2 mm) using standard techniques. Twenty-four individuals (5.3%) retained mesodebris and prevalence varied across species, with foraging technique, food type, and foraging substrate all associated with different metrics of debris ingestion. The odds of ingesting any type of anthropogenic mesodebris was nine times higher for non-raptorial species than for raptors. For a subset of raptors (N = 54) across 14 species, the terminal portion of the distal intestinal tract was digested with potassium hydroxide and microparticles were assessed using stereo-microscopy. Although only one of 54 (1.9%) raptors included in both analyses retained mesodebris in the upper gastrointestinal tract, 24 (44.4%) contained microparticles in the distal intestine. This study demonstrates that a variety of Canadian bird species ingest anthropogenic debris in inland systems, and suggests that life history and behaviour are associated with ingestion risk. For raptors, the mechanisms governing exposure and ingestion of mesoplastics appear to be different than those that govern microplastics. Herring gulls (Larus argentatus) and ring-billed gulls (Larus delawarensis) are proposed as ideal sentinels for plastic pollution monitoring in inland systems.
摘要：
塑料摄入给野生动物带来了许多潜在的风险。了解哪些物种和环境最容易受到塑料污染是研究塑料暴露对健康的影响的关键第一步。这项研究的目的如下：1）利用尸检作为正在进行的被动疾病监测的一部分，调查在安大略省和努纳武特收集的鸟类中摄入的介体，并检查鸟类水平因素与摄入的碎片之间的关系；2）评估与猛禽中摄入的中段碎片相比的微塑料摄入；3）确定潜在的哨兵物种，用于在研究不足的淡水和陆地（内陆）环境中进行塑料污染监测。在2020年至2022年之间，接收了52种457只自由放养的鸟类进行验尸。使用标准技术检查上消化道的中塑料和其他碎片(>2mm)。24个人（5.3％）保留了中质碎片，并且患病率因物种而异，用觅食技术，食物类型,和觅食基质都与不同的碎片摄取指标相关。非猛禽物种摄取任何类型的人为中间碎片的几率是猛禽的九倍。对于14个物种的猛禽子集（N=54），用氢氧化钾消化远端肠道的末端部分,并使用立体显微镜评估微粒.尽管两项分析中包含的54只猛禽中只有1只（1.9％）保留了上消化道的中膜碎片，24(44.4%)在远端肠中含有微粒。这项研究表明，各种加拿大鸟类在内陆系统中摄取人为碎片，并表明生活史和行为与摄入风险有关。对于猛禽来说,控制中塑料暴露和摄入的机制似乎与控制微塑料的机制不同。建议将鲱鱼海鸥（Larusargentatus）和环嘴海鸥（Larusdelawarensis）作为内陆系统中塑料污染监测的理想哨兵。
