| Microplastics are plastic particles <5 mm in size. There are several types of microplastics. One microplastic type, microbeads, were lost as a result of chemical digestion of fish tissues. An assessment of chemical digestion methods found that temperature >60 °C melted some types of microplastics. A room-temperature basic reaction was selected for use in feeding experiments. Six microplastic types were fed to three species of freshwater fish in a laboratory. Some microplastic types may have greater potential for retention in fish digestive tracts. Differences in retention among microplastic types were significant for Rainbow Trout (Oncorhynchus mykiss) but not for White Sucker (Catostomus commersonii) or Fathead Minnow ( Pimephales promelas). Polystyrene foam beads and spherical microbeads were observed in the esophagus and gills of Rainbow Trout respectively, demonstrating potential for accumulation and blockage. Retention of microplastics is a concern for potential physical effects in individuals and ecological effects for impacted fish communities. |
