# Microplastic Pollution: Chemical Characterization and Impact on Wildlife
## 3 Microplastics and Wildlife
### Microplastics in Birds
Also, birds having high MPs showed higher production of malondialdehydedehyde in the liver, intestine, gizzard, and brain, and decreasing effects on hepatic nitric oxide production were found. The antioxidant response marker of the birds exposed to MPs and superoxide dismutase activity in the liver and intestine were decreased by 22.5% and 20.1%, respectively, in relation to the control group. Macro- and microplastic can cause severe multiorgan effects on seabirds. The paper by [PERSON] et al. (2018) investigated the impact of ingested plastics on the free-living flesh-footed shearwaters (_Ardenna carneipes_) and after an unsuccessful fledging attempt, the birds were euthanized under permit after being nest-bound and provisioned by both parents for the previous 90 days. Plastic ingestion is common in flesh-footed shearwaters, and severely affected birds are unable to regurgitate plastics before departing for the sea. The birds used in this study were chosen at random along a gradient of plastic exposure, ensuring that there was a control group of birds (n = 8). They weighed and measured birds with a spring scale, a stopped ruler (\(\pm\)1 mm), and exposed culmen (\(\pm\)0.1 mm) and head + bill (\(\pm\)0.1 mm) using Vernier calipers. Plastic items larger than 1 mm recovered from the gizzard and proventriculus were washed, dried, and weighed to the nearest 0.0001 g using an electronic balance. In free-living seabirds, they discovered pathologically significant tissue- and cellular-level sublethal effects of ingested plastics. In comparison to birds that had little to no ingested microplastics, those that had ingested plastics had a higher inflammatory response, more deterioration of the stomach lining, higher tissue damage scores across multiple organs, and a higher density of embedded micro- and nanoplastics in the proventriculus, spleen, and kidneys. These findings demonstrate the negative and insidious effects of plastic pollution on wildlife that have previously gone unnoticed. They found significant effects of inflammation in inferior regions of the proventriculus of the birds and oedema, erythema (redness), and the loss of tissue structure on the epithelial surface of the proventriculus. Water content was used to assess oedema, and the presence of plastic was associated with significantly higher water content in both the superior and inferior regions of the proventriculus. Ingestion of plastic also resulted in a significant loss of rugae, which plays an important role in digestion and nutrient absorption by increasing surface area and allowing the proventriculus to expand. The density of microplastics (particles/mm\({}^{3}\)) in seabird tissues was significantly correlated with the mass of visible plastics recorded in the proventriculus, implying that the mass of visible plastics recorded in the proventriculus can act as a proxy for the number of microplastics detected in the tissues. This finding suggests that the visual method of identifying microplastics in histological sections is accurate for approximating microplastic exposure, as significant levels of particle misidentification would prevent the discovery of the correlation with microplastic exposure. A blinded observer scored the tissue for pathology on a scale of 0-5, with the pathology score being significantly correlated with proventriculus plastic mass as observed in Figure 11 below. An additional paper has reported the first identification of microplastics in Indonesian seabirds, little black cormorants (_Phalaccoronax sulcirostris_) ([PERSON], 2018). The MPs were identified as present within the digestive tract likely due to ingestion of food which is taken mostly from seawater. The author identified 16 microplastic particles of a different type, size, and color and gave an estimation of 320 particles/bird. MPs were mostly films (75%), followed by fiber (18.75%), and fragments (6.3%) in type. Sizes of the microplastic were mostly (68.7%) between 100-1000 micrometer major dimension.