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Abstract: The acetylthiocholine (ATC) – cleaving cholinesterase (ChE) activity in Manila clam, which is widely distributed throughout the coastal environment of Korea, was assayed as a potentially useful biomarker of organophosphorous pesticides (OPs). A clear dose–response relationship was determined between inhibited ChE in adductor muscle of clams and four OPs (methidathion, chlorpyrifos, diazinon, IBP) which are heavily used OPs in Korea. The measured EC50-24 h values of methidathion, chlorpyrifos, diazinon, and IBP for Ruditapes philippinarum were 7.16 μg l−1, 0.34 mg l−1, 3.01 mg l−1, and 3.41 mg l−1, respectively. In field studies, ChE activity in Manila clams collected from 23 stations in the mid-western coastal region demonstrated spatial variation with statistical differences. These results suggest that ChE activity in R. philippinarum is a potential biomarker for assessing organophosphorous pesticide contamination in coastal environments. [Copyright &y& Elsevier]

Abstract: Terrace stratigraphy of the southeastern coastal areas of Korea has been studied with the help of terrace mapping and geochronology. Coastal terraces include 90–130m upper High Terrace (uHT), 63–86m High Terrace (HT), 36–55m Middle Terrace (MT) and 8–25m Low Terrace (LT) divisions, each of which has been subdivided. Amongst these, LT 2 formed during the late Pleistocene, based on Tephras Aso-4 (MIS 5c), Ata (MIS 5d or 5e) and OSL ages. The age of LT 1–3 ranges from MIS 5e to 5a, based on tephra ages from Aso-4 (ca. 90ka) and Ata (100–125ka). The uplift rate in the SE part of Korea ranges between 0.14 and 0.22mm/a and it is quite small in comparison to the Japanese island arc, or many other tectonically active East and Southeastern Asian regions. [Copyright &y& Elsevier]