# Microplastic Pollution: Chemical Characterization and Impact on Wildlife
## 3 Microplastics and Wildlife
### Microplastics in Aquatic Animals
7 (\(\Sigma\)PAHs2306 \(\pm\) 372.42 ng/g dry weight)) than on day 21 (\(\Sigma\)PAHs 1229 \(\pm\) 165.30 ng/g dry weight) which had an increased prevalence of oocyte atresia. Microphasics also cause intestinal toxicity in _Ambioctopus fungsaio_. In this study, [PERSON] et al. demonstrated _A. fungsaio_ exposed to microplastics at concentration of 100 (low concentration polystyrene microplastics, PS-L) and 1000 (high concentration polystyrene microplastics, PS-H) mg/L for 21 days (about 3 weeks) exhibited physiological changes [76]. These authors found the mean values of reactive oxidative species (ROS) content in the PS-L and PS-H groups have significantly increased (4.19 \(\pm\) 0.069 and 4.31 \(\pm\) 0.050 fluorescence intensity/mg protein, \(p\) < 0.001) in comparison to the control group (3.02 \(\pm\) 0.013 fluorescence intensity/mg protein). In the case of malondialdehydedehyde (MDA) levels, which is commonly known as a marker of oxidative stress, the authors found 2.53 \(\pm\) 0.092 and 2.20 \(\pm\) 0.165 uM/mg protein in PS-L and PS-H groups, but in the control group, it observed 2.59 \(\pm\) 0.066 uM/mg protein which the authors interpret as the level of lipid peroxidation increasing significantly in high concentration of MPs treatment (_p_ < 0.05). Likewise, superoxide dismutase (SOD) (11.80 \(\pm\) 0.550 and 13.75 \(\pm\) 0.51 U/mg protein) and catalase (CAT) (11.03 \(\pm\) 0.650 and 13.12 \(\pm\) 0.61 M/min/mg protein) activities in the intestines of PS-L- and PS-H-treated octopuses were significantly higher than in the control group (9.34 \(\pm\) 0.087 mol/mg protein) (_p_ < 0.001). Thus, the oxidative stress parameter levels SOD and ROS were significantly increased under micro-PS exposure stress, leading to the imbalance of homeostasis. Due to the oxidative damage caused by micro-PS stress, the antioxidant enzyme activities of SOD and CAT were stimulated and increased the risk of various physiological damages in the octopus. Microphasics mixed with certain organic contaminants can cause severe effects on aquatic wildlife [77]. [PERSON] et al. investigated the effects of polystyrene combined with organophosphate pollutant chlorpyrifos in zebrafish. They administered fish feed in combination with polystyrene microplastics with the concentration of 50 and 500 ug/g dry weight which was denoted as PSL (low) and PSH (high), respectively, and chlorpyrifos with the concentration of 0.02, 0.2, 2, 20, and 200 ug/g dry weight feed and denoted as CPF1, CPF2,...... CPF5, respectively. Fish were fed twice daily in a 10 L tank with the contaminated feeds at a level of 2% body weight. The accumulation of microplastics in the gut and liver of fish was observed by fluorescent microscope and found MPs were increased over time and reached steady-state after 4 and 8 days. For PSH and PSL treatments, the maximum amounts of MPs were found as 1.5 \(\times\) 10\({}^{4}\) items/fish for PSH treatment and 6 \(\times\) 10\({}^{3}\) items/fish for PSL treatment. In the liver, they found about 500 and 300 items/individual in PSH and PSL treatments, respectively. Adsorption of chlorpyrifos by MPs followed a pseudo-first-order model, which increased rapidly at first and reached equilibrium at 4 and 8 h for 20 and 200 g/L CPF, respectively. When compared to the control, both single MPs and mixture treatments significantly increased the number of goblet cells (_p_ < 0.05). There was a dose-dependent increasing trend of goblet cells with CPF treatments, but only CPF5 (200 g/g) caused a significant change (_p_ < 0.05). Microplastic alone had limited effects on SOD activity in both fish gut and liver in most of the cases except that PSH inhibited SOD activity by almost 45% after 14 days of exposure. Contrary to SOD, single MPs significantly affected CAT activity in both gut and liver tissues, but in different ways. CAT activity in the gut increased initially but then decreased with increasing exposure time, reaching a peak at 4 and 7 days for PSH and PSL treatments, respectively.