Suchergebnisse

AbstractPlastic waste is recognised as hazardous, with the risk increasing as the polymers break down in nature to secondary microplastics or even nanoplastics. The number of studies reporting on the prevalence of microplastic in every perceivable niche and bioavailable to biota is dramatically increasing. Knowledge of the ecotoxicology of microplastic is advancing as well; however, information regarding plants, specifically aquatic macrophytes, is still lacking. The present study aimed to gain more information on the ecotoxicological effects of six different polymer types as 4 mm microplastic on the morphology (germination and growth) and the physiology (catalase and glutathione S-transferase activity) of the rooted aquatic macrophyte, Nelumbo nucifera. The role of sediment was also considered by conducting all exposure both in a sediment-containing and sediment-free exposure system. Polyvinyl chloride and polyurethane exposures caused the highest inhibition of germination and growth compared to the control. However, the presence of sediment significantly decreased the adverse effects. Catalase activity was increased with exposure to polyvinyl chloride, polyurethane, and polystyrene, both in the presence and absence of sediment but more so in the sediment-free system. Glutathione S-transferase activity was significantly increased with exposure to polypropylene, polyvinyl chloride, and polyethylene terephthalate in the sediment-free system and exposure to polyethylene terephthalate and polyurethane in the absence of sediment. There was no clear correlation between the morphological and physiological effects observed. Further studies are required to understand the underlying toxicity mechanism of microplastics.

Communities with a high degree of vulnerability to disasters often experience greater impact from disasters. Understanding and identifying the extent of community vulnerability to natural disasters, would provide emergency managers and decision-makers with strategic direction in their efforts to improve local communities' capacity to natural disasters while reducing the degree of vulnerability and the negative impacts of disasters. This study aims to develop a methodology for constructing a set of indicators for deriving a community vulnerability index (CVI) in terms of social, physical, and natural environmental factors. The degree of community vulnerability to natural disasters is measured at 229 local municipalities in Korea. Shannon's entropy method is employed to assess the weight of each vulnerability factor in the local communities of Korea. In order to verify the measured CVI, this study also examines the relationship between the aggregated CVI using the entropy method and disaster losses.

DNA barcoding, an inventory of DNA sequences from a standardized genomic region, provides a bio-barcode for identifying and discovering species. Several recent studies suggest that the sequence diversity in a 648 bp region of the mitochondrial gene for cytochrome c oxidase I (COI) might serve as a DNA barcode for identifying animal species such as North American birds, insects and fishes. The present study tested the effectiveness of a COI barcode in discriminating Korean bird species. We determined the 5′ terminus of the COI barcode for 92 species of Korean birds and found that species identification was unambiguous; the genetic differences between closely related species were, on average, 25 times higher than the differences within species. We identified only one misidentified species out of 239 specimens in a genetic resource bank, so confirming the accuracy of species identification in the banking system. We also identified two potential composite species, calling for further investigation using more samples. The finding of large COI sequence differences between species confirms the effectiveness of COI barcodes for identifying Korean bird species. To bring greater reliability to the identification of species, increased intra- and interspecies sampling, as well as supplementation of the mitochondrial barcodes with nuclear ones, is needed. ; This study was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MOST) (No. M10508040002-06N0804- 00210), the Brain Korea 21 Program for Veterinary Science funded by the Ministry of Education, and the Korea National Research Resource Collection Program funded by the Korea Science and Engineering Foundation. We express our appreciation to Mr. Tae Wook Kang for assistance with data analysis and special thanks to Tae Young Choi, Dong Gi Choi, and Chun Gweon Choi for donating road-killed samples collected for the Eco-technopia 21 Project, the Korean Government's R&D Program on environmental technology develop- ment. The authors also thank the Korean Association for Bird Protection in Cheorwon, Korea and the Wildlife Rescue Center in Suncheon for samples.