# Microplastic Pollution: Chemical Characterization and Impact on Wildlife
## 3 Microplastics and Wildlife
### Microplastics in Land Animals  
Blackbirds and song thrustes are commonly used as indicator organisms of microplastic pollution in terrestrial environments. One work investigated differently sized microplastics in the gastrointestinal tracts of dead birds which were mostly consisting of fibers (84%) in northeastern Poland [87]. This work found that all the analyzed birds contained  
Figure 11: The mass of proventriculars microplastics (>1 mm) correlates with organ microplastics (<1 mm) and organ pathology. Inserts (**a**,**e**,**i**): The correlation between the mass of proventriculars microplastics (grams) with tissue microplastics identified through histology in the proventriculars (**a**), kidney (**e**), and spleen (**i**). Inserts (**b**,**f**,**j**): The correlation between the mass of proventriculars microplastics with mean tissue pathology score (0-5) in the proventriculars (**b**), kidney (**f**) and spleen (**j**). Inserts (**c**,**g**,**k**): The correlation between the tissue microplastics with mean tissue pathology score (0–5) in the proventriculars (**c**), kidney (**g**), and spleen (**k**).Inserts (**d**,**h**,**l**): Histological examples of healthy tissue (**i**) and tissue pathology (**ii**) in the proventriculars ((**d**), inflammation and hemorrhage; scalebar 100 \(\upmu\)m), kidney ((**h**), collapsed glomerus around microplastic (arrow), scalebar (\(\upmu\)m), and spleen. Figure reproduced from Ref. [84] under the Creative Commons Attribution License. micoplastic in their gastrointestinal tracts. A total of 1073 microplastic objects were noted, with fibers consisting of 84% and films below 1 mm in size making up approximately 10% of objects. The dominant colors of microplastics were transparent (75%) and brown (14%). The average MP concentration was higher in song thrushes (40.1 objects per bird) compared to common blackbirds (21.9 objects per bird); however, the difference between species was not deemed statistically significant. No seasonal differences or age-related differences in microplastic ingestion in either species were observed. Their findings suggest that thrushes could be used as indicators of microplastic pollution in terrestrial ecosystems. As a result, they recommend the use of such a sampling technique in future work of MP pollutants of wildlife and the ecosystems in which they live. Microplastics can affect the behavior and physiological condition of animals including chickens. [PERSON] et al. (2018) investigated different adverse conditions in chicken health after administering microplastics. In the study they found microplastic exposure decreased growth and antioxidant ability, impaired chickens' viscera, and found a significant decrease in alpha diversity, accompanied by taxonomic composition alterations in gut microbiota in chicken that leads to hampering the nutrition metabolism and gut microbial homeostasis in chicken. This study may serve as inspiration for ecologic agencies around the world to regulate the use and disposal of plastic products to reduce environmental pollution. They also discovered a production connection or interaction between the gut microbiota and metabolites, expanding our understanding of the functions of gut-residing bacteria and their metabolites. Furthermore, it demonstrated that the interaction between gut microbiota and metabolites may be one of the mechanisms by which MPs exert their negative effects. Airway contamination of microplastics can cause severe health problems in mice. The [PERSON] et al. (2018) showed that respiratory microbial dysbiosis is induced by microplastics/nanoplastics in mice. There were multiple bacteria (nasal staphylococcus, lung Roseburia, lung _Eggerthella_, and lung _Corynebacterium_) which were potential biomarkers of micro/nanoplastic inhalation for respiratory illness.