First report of the microgastropod Ammonicera japonica (Omalogyridae Habe, 1972) in Korea

The intertidal zone of Jeju Island, Korea, is characterized by well-developed volcanic rocks with high wave action. During low tide, numerous small tidal pools are formed on the rocky intertidal zone, which provide shelter and habitats for benthic organisms. Previous investigation indicated that many species of micromolluscans inhabit the tidal pools; however, only a few studies have reported the ecology and identification of these microshells. In this study, we have identified a microgastropod, Ammonicera japonica Habe, 1972 (Omalogyridae), from a tidal pool on the southern coast of Jeju Island. Morphological identification of the species was based on scanning electron microscopy (SEM) of the protoconch and teleoconch. A. japonica was found to be associated with encrusting coralline algae distributed on the bottom of the tidal pools. This is the first report of A. japonica from Korea, and the specimen was registered at the National Marine Biodiversity Institute of Korea (MABIK MO00157413)

Instrumental and bioanalytical measures of dioxin-like compounds and activities in sediments of the Pohang Area, Korea

Pohang is a mid-sized city in which Korea's largest manufacturer of steel is located. The Hyeongsan River, which runs through Pohang and empties into Yeongil Bay, is therefore expected to be affected by various municipal and industrial inputs. In order to characterize aryl hydrocarbon receptor (AhR)-mediated activities in sediments from the Pohang area, a total of eight locations along the Hyeongsan River were chosen and 16 sediment samples were collected during two sampling campaigns in 2010. Organic extracts of sediments were characterized by both quantitative chemical analyses of dioxin-like chemicals and the in vitro H4IIE-luc bioassay. Significant dioxin-like activities were observed in sediments from industrial and municipal areas, which indicates that most of the dioxin-like chemicals were associated with surrounding anthropogenic sources. In general, responses of the H4IIE-luc assay were significantly correlated with concentrations of target compounds including dioxins, furans, co-planar PCBs, and dioxin-like PAHs. A potency balance analysis indicated that instrumentally derived TCDD equivalents (TEQs) explained about 77% of the bioassay-derived TCDD equivalents (TCDD-EQs). Among the target chemicals measured, certain penta-chlorinated dioxin and furan compounds accounted for the majority of dioxin-like activities associated with sediments. Compositional analysis of target chemicals the sources of such dioxin-like activities were mainly derived from the local activities such as the iron and steel industries. Concentrations and activities of AhR agonists were similar to what was measured approximately 10 years ago. Thus, while AhR agonists seem to be persistent in sediments there seem to have been no large increases in these chemicals in the Pohang area.close2

Species- and tissue-specific bioaccumulation of arsenicals in various aquatic organisms from a highly industrialized area in the Pohang City, Korea

Contamination of water and sediment with arsenic (As) in a highly industrialized area of Pohang City, Korea was investigated, with emphasis on in situ bioaccumulation of arsenicals by various aquatic organisms. Species- and tissue-specific concentrations of arsenicals were determined by use of HPLC-ICP/MS and ??-X-ray absorption near-edge structure (??-XANES). Concentrations of arsenic in aquatic organisms were strongly associated with corresponding water concentrations, which indicates point sources associated with land use and activities. Arsenobetaine was the most dominant form of arsenic found in fishes, bivalves, crabs, and shrimps, while AsIII was predominant in freshwater snails. The ??-XANES analysis provided additional information about the unidentified arsenicals such as As-thiol. Arsenicals were mainly localized in intestine of mullet and marsh clam. Distribution and bioaccumulation of arsenic were strongly correlated with salinity, which indicates that natural processes controlling biogeochemistry of arsenic would be important in estuarine lotic system.close0

Two Years after the <i>Hebei Spirit</i> Oil Spill: Residual Crude-Derived Hydrocarbons and Potential AhR-Mediated Activities in Coastal Sediments

The <i>Hebei Spirit</i> oil spill occurred in December 2007 approximately 10 km off the coast of Taean, South Korea, on the Yellow Sea. However, the exposure and potential effects remain largely unknown. A total of 50 surface and subsurface sediment samples were collected from 22 sampling locations at the spill site in order to determine the concentration, distribution, composition of residual crudes, and to evaluate the potential ecological risk after two years of oil exposure. Samples were extracted and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs), 20 alkyl-PAHs, 15 aliphatic hydrocarbons, and total petroleum hydrocarbons using GC-MSD. AhR-mediated activity associated with organic sediment extracts was screened using the H4IIE-<i>luc</i> cell bioassay. The response of the benthic invertebrate community was assessed by mapping the macrobenthic fauna. Elevated concentrations of residual crudes from the oil spill were primarily found in muddy bottoms, particularly in subsurface layers. In general, the bioassay results were consistent with the chemistry data in a dose-dependent manner, although the mass-balance was incomplete. More weathered samples containing greater fractions of alkylated PAHs exhibited greater AhR activity, due to the occurrence of recalcitrant AhR agonists present in residual oils. The macrobenthic population distribution exhibits signs of species-specific tolerances and/or recolonization of certain species such as <i>Batillaria</i> during weathering periods. Although the <i>Hebei Spirit</i> oil spill was a severe oil exposure, it appears the site is recovering two years later