Office for Environmental Programs - Theses
Permanent URI for this collection
Search Results
1 - 2 of 2
-
ItemWhat is the impact of glitter, as a type of microplastics, on springtail, Folsomia candida?( 2022)With the rapid development of urbanization, plastics are continuously produced in the industry, and large amount of them are released to the environment. When plastics released to the environment, they could be degraded by physical, chemical, or biological approaches to form microplastics. Microplastics, the mixed plastics with size smaller than 5 mm, have raised more concern than before as an emerging contaminant that can affect the environment and ecosystem. Furthermore, microplastics have high variety on their size, shape, and polymer type, which increase the difficulty to measure their toxicity and quantify them in natural environments. Glitter, a primary source of microplastics, is usually used in cloth and cosmetic, which normal structure include a polymer coating, a colored aluminum coating, and core PET film. Glitter may directly release to the environments because there is no regulation on the recycle of glitter, and thus many researchers urged to promote biodegradable glitter, a plant-based glitter, as an alternatives to replace conventional PET glitter. However, there may have already large amounts of PET glitter released to the environment, but previous studies on microplastic analysis usually ignored resulting from the pretreatment of sample cannot filter out the PET glitter. In terrestrial environment, glitter may cause the detrimental effect on soil invertebrate, leading to the survival decrease and reproduction inhibition. Therefore, it is critical to estimate the toxicity of PET glitter as well as biodegradable glitter. In this study, an exposure experiment is conducted to assess the toxicity of microfine PET glitter and two biodegradable glitters on the survival and reproduction of Folsomia candida, which is a collembola species widespread in the world. The results showed that reproduction was inhibited when F. candida expose to microfine PET glitter at the concentration of 1000 mg/kg. In contrast, no significant reproduction inhibition and survival decrease is observed when F. candida expose to two types of biodegradable glitters. Therefore, it implies that biodegradable glitter has lower toxicity than PET glitter, and biodegradable glitter can be an alternative to replace PET glitter. There are two possible mechanisms: Chemical toxicity by glitter additives and alteration of feeding behavior. These assumptions require further investigation, which is pointed out as future direction.
-
ItemCurrent state-of-the-art methods, equipment and analyses in soil ecotoxicology( 2022)Soil ecotoxicology study the impact of pollutants on soil ecosystem, which has been developed for more than 50 years. After the first soil ecotoxicology study published in 1960s, the methodology of soil ecotoxicity test was rapidly developed to support the ecological risk assessment. Many standardized ecotoxicity tests were established by international organizations (OECD and ISO) to provide researchers and industries to produce a comparable ecotoxicity data that can improve the understanding of mechanisms of toxicity. However, researchers started to notice the limitations of standardized ecotoxicity test to solve more complicated pollution issues raised in recent years. These issues include the reproducibility and reliability of standard ecotoxicity test, the limited information gained from ecotoxicity test, and the challenge in ecological risk assessment from laboratory experiments to field study. Currently, several novel methodologies, technologies, and analysis in soil ecotoxicology, such as full life cycle ecotoxicity test, continuous monitoring techniques, and eDNA metabarcoding, are proposed as a potential tools used in ecological risk assessment. These novel developments have high potential to deal with the challenges raised in soil ecotoxicology, while no literature review provide a holistic view to summarize them and link with modern pollution issues. Therefore, this article introduce the the historical perspective of soil ecotoxicology, summarize the pollution issues raised in recent years, and point out the state-of-the-art methodology, technology, and analysis in soil ecotoxicology.