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The microplastics in the surface seawater at 23 fixed points in the southwestern waters of Jeju Island were analyzed to conduct a study on the distribution characteristics of microplastics. The abundance of microplastics was shown to be 0.17 ~ 1.37 (average 0.46) n/L, the materials were mainly PP and PE, and the shape of fragments was dominant in the 0.02–0.3 mm group in terms of sizes and shapes. Alkyd and polyester were dominant in the shape of fibers in the 1.0–5.0 mm group. The correlations between the abundance of microplastics, water temperatures, and salinity were compared and as a result, water temperatures, PE, and the 0.02–0.3 mm size group, and the shape of fragments showed negative correlations. Therefore, it is judged that the for PE, which are in the form of 0.02 ~ 0.3 mm fragments to flow into the study area through the Yellow Sea coastal current and the Korean coastal current that show tendencies of relatively low water temperatures. However, since salinity and PP and polyester showed positive correlations, it is judged the possibility for polyester, which are in the form of 1.0 ~ 5.0 mm fibers, to flow into the study area through the Taiwan warm current and Tsushima warm current. In conclusion, it could be judged that in the complex open waters where continental and oceanic waters intersect, the sources of inflow may be different depending on the components of microplastics.

In this study, we determined 13 perfluoroalkyl substances (PFASs) concentrations in 514 samples of blood, liver, muscle and egg tissues of ten edible freshwater fish species from major rivers and lakes in Korea. The sample was extracted by ion-pair extraction (IPE) method and analyzed by Shimadzu HPLCMSMS 8040. Besides, the Total Daily Intake (TDI) of PFASs and potential risk of human exposure by freshwater fish consumption in several scenarios were investigated. The greatest total PFASs concentration in each fish tissue was found as 925 ng/mL in a crucian carp (Carassius auratus) for blood, 598 ng/g ww in a Korea piscivorous chub (Opsariichthys uncirostris) for liver, 283 ng/g ww in a crucian carp (Carassius auratus) for egg, and 129 ng/g ww in a skygager (Erythroculter erythropterus) for muscle. The greatest mean concentration of PFOS was determined in blood (38.8 ng/mL), followed by egg (22.0 ng/ww), liver (21.1 ng/g ww) and muscle tissues (1.14 ng/g ww). Addition to fish species and tissues, several other factors such as sex, habitat and fish traits, may affect the bioaccumulation of PFASs in fish. The consumption guideline of one meal per week for skygager is strongly applied for skygager caught from a middle stream of Nakdong River watershed. The total daily intake of PFASs by freshwater fish muscle tissues consumption were ranged from 0 to 12.4 ng/kg b.w./day for PFOS and from 0 to 0.05 ng/kg b.w./ day for PFOA. This study firstly reports the tissues distribution and human consumption exposure of PFASs in various edible freshwater fish from major rivers and lakes in Korea. The contamination levels of PFOS and PFOA in the fish muscles in this study were unlikely to pose an immediate risk to the Korean general population or Korean freshwater fish consumer population.

The occurrence and distribution of cyclic and linear siloxanes were investigated in South Korean river water and sediment, with a special focus on crucian carp tissues, to evaluate the residual status and potential bioaccumulation of siloxanes. The total siloxanes median concentrations observed in this study were 1495 ng/L in river water, 39.2 ng/g-dry weight [dw] in sediment, and 41.7 ng/g-wet weight [ww] in crucian carp muscle. Cyclic siloxanes (D3-D6) were predominant in all matrices, and D5 (mean:81%) was more abundant in biota tissues than in river water (30%) and sediment (26%) samples. Specifically, positive correlations between D5 concentrations and crucian carp sizes (p 0.01, Spearman) as well as the relatively high estimated biota-sediment accumulation factor value of D5 (D5: 2.31), suggest the high bioaccumulative property of D5 in biota. However, no bioaccumulation potentials were observed for D3, D4, D6, and L3-L17 in this field-scale study. The distributions of major linear siloxanes (L7-L14) in crucian carp gills (17%) and gonads (21%) were higher than in other tissues (brain, 9.6%; liver, 2.6%; muscle, 1.5%). Moreover, relatively high tissue/plasma ratios were observed for linear siloxanes (L7-L10: 1.79-2.12) compared to cyclic siloxanes (D4-D6: 0.829-1.18) (p 0.01, Mann Whitney U test), which indicated the higher transportability of linear siloxanes to fish tissues than cyclic siloxanes.

Thirteen PFASs in water (n = 58), sediment (n = 58) and edible fish samples (n = 81) collected from three special management sea areas of Korea including Gwangyang bay, Masan bay and Busan harbor in July 2018 were investigated. The mean PFASs concentration in water (ng/L) were in order Masan (5.09) > Busan (2.82) > Gwangyang (1.74). PFASs levels were found as the low concentration in sediment. The greatest total PFASs concentration in each fish tissue was found as 3.04 (ng/g ww) in a Japanese amberjack fish for muscle in Busan, 66.23 (ng/mL) in Japanese amberjack fish for blood in Masan and 125.03 (ng/g ww) flathead grey mullet in Busan bay. The BCF (L/kg) of PFDoDA was found as the highest in muscle of all species with values from 30,922 (grey mullet in Gwangyang) to 69,131 (grey mullet in Busan). PFDS was the highest BCF's PFASs (110,599 L/kg) in muscle which was found in Japanese amberjack in Busan bay.

A simultaneous monitoring study on organotins (butyltins and phenyltins) and most frequently used alternative antifouling biocides (Irgarol 1051, Diuron, Sea-Nine 211 and M1) in water and sediments (n=44) collected from three Special Management Sea Areas operated by Korean government. The lower concentration of butyltins (BTs) than that of new antifouling biocides (NEW) was found in water but the significant greater concentration of BTs than that of NEW was still found in sediments. The tributyltin (TBT) levels in water exceeded the chronic criterion to protect seawater aquatic life at several sites. Even ten years after the ban of the use of TBT-based antifouling paint, the concentrations of TBT, Diuron and Irgarol 1051 in sediments from shipyards exceeded global sediment quality guidelines and potentially poses adverse risks on marine organisms and extremely high concentration of TBT up to 2304ng/g was found for a sediment collected at a shipyard.

To examine how tributyltin (TBT), a model obesogen, affects the lipid metabolism in the marine rotifer Brachionus koreanus, we carried out life-cycle studies and determined the in vitro and in silico interactions of retinoid X receptor (RXR) with TBT, the transcriptional levels of RXR and lipid metabolic genes, and the fatty acid content. The lethal concentration 10% (LC10) was determined to be 5.12 μg/L TBT, and negative effects on ecologically relevant end points (e.g., decreased lifespan and fecundity) were detected at 5 μg/L TBT. On the basis of these findings, subsequent experiments were conducted below 1 μg/L TBT, which did not show any negative effects on ecologically relevant end points in B. koreanus. Nile red staining analysis showed that after exposure to 1 μg/L TBT, B. koreanus stored neutral lipids and had significantly increased transcriptional levels of RXR and lipid metabolism-related genes compared to the control. However, the content of total fatty acids did not significantly change at any exposure level. In the single fatty acids profile, a significant increase in saturated fatty acids (SFAs) 14:0 and 20:0 was observed, but the contents of omega-3 and omega-6 fatty acids were significantly decreased. Also, a transactivation assay of TBT with RXR showed that TBT is an agonist of Bk-RXR with a similar fold-induction to the positive control. Taken together, these results demonstrate that TBT-modulated RXR signaling leads to increase in transcriptional levels of lipid metabolism-related genes and the synthesis of SFAs but decreases the content of polyunsaturated fatty acids (PUFAs). Our findings support a wider taxonomic scope of lipid perturbation due to xenobiotic exposure that occurs via NRs in aquatic animals.

Perfluoroalkyl substances (PFASs) have been found in water environment globally. However, the difference on occurrence profiles between PFASs in water from coastal areas and inland rivers or/and agricultural areas is still limited. In this study, the presence of thirteen PFASs in sixty-five surface water samples collected from coastal areas of three southeastern industrialized bays, four major rivers, and six rice field areas in Korea were analyzed. Total PFAS concentrations (ng/L) range from 0.22-73.9 (mean=22.1) for the major rivers, 0.54-3.19 (mean=1.77) for the rice field areas, and

In this study, a comprehensive investigation was performed to understand the overall occurrence, relative distribution, and bioaccumulation of seven different groups of POPs, comprising 27 polybrominated diphenyl ethers (PBDEs), 76 polychlorinated biphenyls (PCBs), 23 organochlorine pesticides (OCPs), three hexabromocyclododecanes (HBCDs), and 13 perfluoroalkyl substances (PFASs) as legacy POPs, and 41 polychlorinated naphthalenes (PCNs) and 24 short-chain chlorinated paraffins (SCCPs) as emerging POPs, by monitoring crucian carp, sediment, and river water in the freshwater system. Among the targeted POPs, SCCPs were predominant in sediment and crucian carp (more than 95%), while a dominance of PFASs was observed in river water (92%). Principal component analysis revealed four different groups/patterns of POPs in all media: one for PBDEs, PCBs, and OCPs, another for HBCDs and PFASs, and the two others for PCNs and SCCPs. Also, sexually dimorphic growth-dependent accumulation of legacy POPs was observed in crucian carp such that POPs concentration increased with increasing fish size and males recorded significantly higher levels of POPs compared to females. Keywords: Persistent organic pollutants, Overall monitoring, Relative distribution, Growth-dependent accumulation, Maternal transfer

The occurrence and distribution of 41 congeners of polychlorinated naphthalenes (PCNs) were investigated in major tissues of crucian carp (muscle, gonad, liver, and blood) and in river sediment to assess the bioaccumulation potential of PCNs. The total PCN concentrations in sediment ranged from 4.37 to 19.5 pg/g dry weight (dw), mainly comprising CN-13, CN-33/34/37, and CN-38/40. Among fish tissues, higher PCN concentrations were observed in the gonads (29.6 ± 10.3 pg/g wet weight, ww) and liver (25.7 ± 4.35 pg/g ww) of crucian carp than in the muscle (2.17 ± 0.68 pg/g ww). CN-28/43, CN-33/34/37, CN-42, CN-52/60, CN-53/55, and CN-66/67 congeners were detected most frequently and had the highest concentration among all crucian carp tissues. We investigated the association between the PCN concentration in each tissue (muscle, liver, and gonad) and the size of the fish (total length and weight) and found positive correlations between the PCN concentration in the gonads and the total length and weight (p 0.05, Spearman correlation).

The concentrations, distributions, and bioaccumulation of nine organophosphate flame retardants (OPFRs) were investigated in both abiotic and biotic media, comprising river water, sediment, and crucian carp. The highest concentrations were observed in liver (6.22–18.1 ng/g ww), and the levels in muscle (4.23–7.75 ng/g ww) and gonad (3.08–7.70 ng/g ww) were similar. In whole blood, tris(2-butoxyethyl) phosphate (TBOEP; 31.1–256 ng/mL) accounted for 90% of the total OPFR concentration. Distributions of OPFRs differed between biotic and abiotic media, as tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCIPP), and TBOEP were dominant in abiotic media, whereas triethyl phosphate (TEP), tri-n-butyl phosphate (TNBP), TCEP, and TBOEP dominated in crucian carp. The TNBP had remarkable accumulation potential among nine OPFRs, which the TNBP concentrations in muscle increased with increased total length and body weight. The higher perfusion rate of TNBP to female eggs were observed rather than to male gonads as the concentrations were higher in males than in females, while the opposite results were observed in gonad. Moreover, the concentration of TNBP in female muscle began to decrease near maximum growth as a sexually dimorphic difference in crucian carp. This is the first study to simultaneously investigate the fate of OPFRs in biotic and abiotic media and to show sex differences.

The occurrence and distribution of hexabromocyclododecanes (HBCDs) were investigated in freshwater, sediment, and selected crucian carp (Carassius carassius) tissues (muscle, liver, egg, and blood) to evaluate the potential for HBCDs bioaccumulation. The HBCDs concentration ranged from not detected to 0.35ng/L in freshwater, and from 0.037 to 35.4ng/g-dw in sediment. The highest HBCDs concentration was detected in crucian carp liver (5.14±8.15ng/g-ww), followed by egg (3.88±10.1ng/g-ww), blood (0.61±0.63ng/mL), and muscle (0.38±0.70ng/g-ww). In all crucian carp tissues, α-HBCD was the predominant stereoisomer, and the fraction of α-HBCD as a proportion of the total HBCDs in liver tissue (96%) was higher than that in egg tissue (79%). There was a positive correlation between the HBCDs concentration in crucian carp muscle and body size (p0.01, Spearman). The biota-sediment accumulation factor (BSAF) (0.14) and bioconcentration factor (BCF) (137,000L/kg) values were estimated in crucian carp muscle using field-based data.

Water, sediment, plankton, and blood and liver tissues of crucian carp (Carassius auratus) and mandarin fish (Siniperca scherzeri) were collected from six major rivers and lakes in South Korea (including Namhan River, Bukhan River, Nakdong River, Nam River, Yeongsan River and Sangsa Lake) and analyzed for perfluorinated alkyl substances (PFASs). Perfluorooctane sulfonate (PFOS) was consistently detected at the greatest concentrations in all media surveyed with the maximum concentration in water of 15 ng L(-1) and in biota of 234 ng mL(-1) (fish blood). A general ascending order of PFAS concentration of watersedimentplanktoncrucian carp tissuesmandarin fish tissues was found. Except for the Nakdong River and Yeongsan River, the sum PFAS concentrations in water samples were below 10 ng L(-1). The PFOS and perfluorooctanoic acid (PFOA) concentrations in water did not exceed levels for acute and/or chronic effects in aquatic organisms. High concentrations of long chain perfluorocarboxylates (LCPFCAs) were found in sediment samples. PFOS, perfluoroundecanoic acid (PFUnA), perfluorododecanoic acid (PFDoA) and perfluorodecanoic acid (PFDA) accounted for 94-99% of the total PFASs concentration in fish tissues. The mean ratios of PFAS concentration between fish blood and fish liver were above 2 suggesting higher levels in blood than in liver. Significant positive correlations (r0.80, p0.001) were observed between PFOS concentration in blood and liver tissues of both crucian carp and mandarin fish. This result suggests that blood can be used for nonlethal monitoring of PFOS in fish. Overall, the rank order of mean bioconcentration factors (BCFs) of PFOS in biota was; phytoplankton (196 L/kg)zooplankton (3,233 L/kg)crucian carp liver (4,567 L/kg)crucian carp blood (11,167 L/kg)mandarin liver (24,718 L/kg)mandarin blood (73,612 L/kg).

Seasonal characteristics of water and sediment qualities and potential effects of the freshwater discharge from a small tide embankment interior in a coastal area in Goheung county were investigated from May to September in 2012. Chemical oxygen demand values (COD) were mostly higher than 2 mg/L in summer ebb tide, which exceed the standard value of water quality criteria II of acceptable level for aquaculture activities. Nitrogen and phosphorus were found as the limiting nutrients for algae growth in summer and fall and in spring, respectively. Nitrogen was the limiting nutrient for diatom growth in the whole studied period. The sudden high values of COD, ammonia, dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) were found in water sample collected from station 5 which located in front of the tide embankment sluice gate during spring ebb tide. The freshwater discharge form the tide embankment interior maybe affected the survey areas during a short time interval. Mean values of eutrophication index of the surveyed coastal region in spring, summer and fall were all bigger than 1. Water quality was mostly considered at level II which acceptable for aquaculture activities. Sediment quality in this study was generally in the range of standard for fisheries environment.

Six organotins including monobutyltin, debutyltin, tributyltin (TBT), monophenyltin, dephenyltin (DBT), triphenyltin were analyzed to investigate a status and effects of a shipyard to organotins pollution in seawater and sediment from 31 sampling sites, in total, in Jinhae Bay. TBT (mean concentration=2.24 ng/L as Cl) and DBT (mean concentration=3.69 ng/L as Cl) were found as two dominant organotins in water samples. In sediment samples, TBT, which has mean concentration of 53.4 ng/g wet weight as Cl and accounted for 74% in total organotins concentration, in average, was consistently found as the predominant organotin. Phenyltins were not found or found as low concentrations comparing with butyltins. Remarkable geographic distribution of TBT and butyltin compounds showed lower concentrations of those compounds in sampling sites located far from the shipyard.

Organotin compounds are considered to be dangerous chemicals because of their deleterious effects on non-target marine organisms. In 2003, the use of TBT-based antifouling paints was totally banned in Korea, and the International Maritime Organization (IMO) proposed to extend the ban to almost all ocean-going vessels. In this study, the concentrations of organotins in the coastal environment are analyzed to illustrate the differences of these analyzed items in the periods before and after the IMO and Korean regulations, focusing on organotins concentrations in molluscan soft tissues and the imposex phenomenon in the rock shell (Thais clavigera), a gastropod species sensitive to organotin compounds, collected from the Korean coasts from 1995 to 1997 and 2002, and from 2005 to 2009. TBT and TPhT were dominant organotins. Higher organotin concentrations were observed in areas with frequent shipping activities, including regions adjacent to harbors or shipyards, than in areas away from shipping activities. Concentrations of TBT, TPhT, and their metabolites in tissue, imposex frequency, and relative penis length index and sterility ratio of rock shell specimens collected from the southern coast after the regulations for TBT- and/or TPhT-based antifouling paints were in place showed lower values than those before the regulations. Because of the continued occurrence of imposex in the rock shell populations after the regulations were established, it is necessary to carry out further studies to monitor organotin concentrations in tissues and imposex frequency of rock shell specimens along with evaluations of the organotins residues in seawater and sediment in Korean coastal areas.

PAHs(Polycyclic Aromatic Hydrocarbons) in coastal area and estuary adjacent to urban area and industrial activities region are mainly introduced into marine environment via atmosphere and river. This study which is evaluated the distribution characteristics of PAHs discharge from rivers and sewage disposal water which flowing into Ulsan bay, and were carried out in Jun of dry season and in Auguest of wet season, 2008. The water samples from eight main rivers and Youngyeon WWTP(Wastewater Treatment Plant) flowed into Ulsan bay were taken for analysis of dissolved PAHs. The range and mean values of dissolved PAHs concentrations showed 10.30 to 87.88 ng/L, its mean 36.94 ng/L in dry season and 10.30 to 69.57 ng/L, its mean 24.37 ng/L in wet season. The distribution of dissolved PAHs showd the high concentrations in the Gungcheoncheon which is flowed from urban and industrial area. The ranges and means values of the loading fluxes were estimated with 0.04 to 8.27 g/day, its mean 2.05 g/day in dry season, and 0.03 to 4.77 g/day, its mean 1.61 g/day, in wet season. The loading flux showed the highest value in Taewha river due to the high flow rate and the urban activity. The composition patterns of dissolved PAHs compound showed most of the trend occupying low molecuar weight PAHs than high molecular weight PAHs. These results were due to physical and chemical characteristics of PAHs compound, and were similar to those of other studies. The concentrations of dissolved PAHs in this study are lower than those of other studies, and the level of PAHs pollution appeared to be not serious in reverine waters of Ulsan coast.

Concentrations of polybrominated diphenyl ethers (PBDEs) were determined in seawater, sediment and biota collected from Gwangyang Bay, Korea. Total concentrations of PBDEs in seawater and sediment ranged from 56.1 to 343 pg/L and from 1.16 to 43.6 ng/g dry weight, respectively. Total concentrations of PBDEs in edible tissue and liver samples ranged from 1.79 to 67.9 ng/g lipid weight and from 1.69 to 10.5 ng/g lipid weight, respectively. The concentrations of PBDEs in sediment measured in our study were moderate or lower than those reported for rivers and coasts from other countries. The highest concentrations of PBDEs in seawater and sediment were found at several stations near petrochemical and steel industrial complexes, suggesting industrial activities contributed to the PBDE contamination in the bay. The major congener of PBDEs in seawater and sediment was BDE 209, which is consistent with a consumption pattern of brominated-flame retardant market in Korea. Fish, bivalve and crustacean had different accumulation patterns of PBDEs, suggesting different diet, habitat and/or bioaccumulation behavior for PBDEs. The bioconcentration factors (BCFs) of all of the PBDE congeners ranged from 102 to 105. The BCFs of PBDE congeners in fish species increased as the octanol-water partition coefficient (Kow) was close to log Kow≈8, above which they decreased. Bivalves appeared slightly bioaccumulation potentials for higher-brominated congeners such as BDE 209 with a high log Kow. Our results suggest that Kow can be a major factor governing bioconcentration mechanism of PBDEs, with minor factor by habitat of target species.

Water, sediment, various tissues of fish, crustacean, gastropod and bivalve were collected from major river basins in Vietnam and analyzed for the presence of perfluorinated alkyl substances (PFASs). Furthermore, the occurrence of PFASs in coastal, tap and well waters collected from eight different regions in Vietnam was investigated. PFOA and PFOS were consistently detected as the dominant PFASs in surface waters. The greatest concentrations of PFOA (53.5ngL-1) and PFOS (40.2ngL-1) were found in a surface water sample collected from a channel that receives wastewater treatment plant discharges. PFOS and PFHxS were found as the predominant PFASs in sediments. The greatest PFAS concentration in biota was 16.9ng PFUnDA g-1 wet weight found in a fish liver. Some long-chain PFCAs including PFNA, PFUnDA and PFTrDA as well as PFHxS were more abundant than short-chain PFASs in biota tissues. The measured concentrations of PFOS and PFOA in surface and tap waters were below the provisional health advisory. The rank order of mean bioconcentration factor of PFOS in biota was; crustacean (115L/kg), gastropod (1117L/kg), fish (1120L/kg) and bivalve (2110L/kg). This study provides baseline information for a better understanding of PFASs contamination in Vietnam.

Concentrations of organotin compounds (OTCs) were measured in the muscle and liver of two fish species (Paralichthys Olivaceus and Mugil cephalus) collected in the six developed coastal regions of Korea: Incheon, Gunsan, Yeosu, Masan, Pohang and Jeju. Concentrations of butyltin compounds (ΣBTs) in the muscle and liver of the two fish species were detected in the range of 1.7–28.8 (mean: 8.8) ng/g-wet wt. as Cl and 18.7–5,096.9 (mean: 832.6) ng/g-wet wt. as Cl, respectively. Concentrations of phenyltin compounds (ΣPTs) ranged

A numerical simulation of the polycyclic aromatic hydrocarbons (PAHs) in Masan Bay, Korea, was con- ducted using a program written in STELLA to estimate the transport of organic chemicals in the coastal environment. A sensitivity analysis of dissolved PAHs and PAHs in suspended particulate matter (SPM) indi- cated that PAH levels were significantly influenced by the settling velocity, the adsorption and desorption rates. PAHs in phytoplankton were sensitive to all coefficient. The mass balance model indicated that the standing stocks of PAHs in water, in SPM, and in phytoplankton were 2.01×10 4 g, 1.15×10 3 g, and 7.5×10 -1 g, respectively. Flux were characterized by a high rate of desorption, followed by descending rates of adsorp- tion, settling, and flow to the open sea. The scenario predicted a "safe" concentration level of dissolved PAHs of less than 30 ng/L if the input loads from rivers, the atmosphere, or both rivers and the atmosphere were reduced to 50%, 50%, or 30% of the current levels, respectively.

This study investigated the bioaccumulation effects of endocrine disruption chemicals (EDCs) such as Tributyltin (TBT), Nonylphenol (NP) and Bisphenol-A (BPA) on flounder,Paralichthys olivaceus. The exposure experiment with the flow through system was performed to examine the effects of bioconcentration for single or multi-chemicals. In the muscle of flounder exposed to TBT, the concentrations of TBT were significantly increased compared with the control tank after two months. It is markedly more accumulated in the liver of the flounder than in the muscle. TBT in muscle of the low level of EDCs were highly accumulated in single exposures of TBT compared to multi-chemical exposure with NP and/or BPA. The concentrations of TBT in muscle were increased in the multi-chemical exposure system. The concentration of TBT in the liver of flounder showed a slight decrease in the multi-chemical exposure system. The metabolites of TBT, DBT and MBT were also concentrated in the muscle and liver. NP and BPA in the muscle of flounder were accumulated with high concentration of EDCs. NP and BPA in muscle were significantly decreased compared with TBT after the depuration period.

Class Gastropoda includes a large number of described species, many with extensively rearranged mitochondrial genomes. We sequenced the mitogenome of the rock shell, Thais clavigera (Gastropoda: Muricidae), an intertidal snail, using long PCR with primers designed on the basis of expressed sequence tags. The mitogenome of T. clavigera consists of 2 rRNAs, 22 tRNAs, and 13 protein-coding genes, but no control region. Structural comparisons revealed that the order Sorbeoconcha, including T. clavigera, have nearly identical mitochondrial gene patterns. However, they have an inversion between a tRNAPhe–tRNAGlu cluster that comprises 21 genes, but most of the remaining structure is similar to the putative mollusk ground pattern. These findings will provide a better insight into mitochondrial gene rearrangement over the course of gastropod evolution.

Residual PEGs in surface river water and sediments were measured at Nakdong River watershed. In this research considering hazards to human and environment, to understand the behavior of PFGs within inorganic materials while moving through river system, and evaluated inter-media distribution characteristics and the influence of river flow from Seonsan to estuary dike of Nakdong River. In surface water, the concentration of PEGs were detected the order as PFOA >PFNA>PFOS>PFHxS>PFOSA, and in sediments the order was PFOS>PFNA=PFOA>PFHxS=PFOSA. Carboxyl series, PFOA and PENA, showed high concentration in surface water, PFOS, PFHxS, and PFOSA were detected with low concentration. The concentration of PFOA and PFNA were relatively high in Nakdong River watershed and it is mainly due to the effects Geumho River.

In recent years, environmental pollution by phannaceuticals and personal care products (PPCPs) in the aquatic environment is of great concern worldwide. Recent studies have been reported to occur in a variety of environmental organisms such as surface, drinking and ground water, soils, sediments and hospitals. The purpose of this study was to evaluate the occurrence and environmental behavior of fourteen human PPCPs in surface waters of Mankyung River in South Korea. We were conducted to field survey for water quality and PPCPs analysis at November, 2006. PPCPs were analyzed by liquid chromatograph coupled with a tandem mass spectrometer (HPLC-MS/MS). The concentration of COD was measured to be 2.3719.71 mg/L, which was belong to 45 grade in water quality criteria of lake. Station 2 that there is no pollution in upper stream, was appeared to lower concentration. The concentration of TN and TP, that is cause matter of eutrophication, were found to be 7.7835.42 mg/L and 0.080.95 mg/L, respectively, which were exceeding 5 grade in Lake water quality criteria. The 11 kind of PPCPs compounds except levofloxacin and triclosan were detected to Mankyung river. PPCPs concentrations of STP(Sewer Treatment Plant) effluents and aquatic environment in Mankyung river have been detected in the range from dozens of ng/L to hundreds of that by order of atenolol, carbamazepine, propranolol, Ibuprofen, erythromycin, ifenprodil, clarithromycin, mefenamic acid, fluconazole, indomethacin, disopyramide. PPCPs concentration of Station 1 and 5, which was influenced by Jeonju STP and Wanju STP, was detected high values. Station 2 that there is no pollution, showed lower values. Station 3 which joined Gosan stream and Jeonju stream and station 4 which influenced by stock wastewater was detected to low values.

This study was carried out on the ark shell Scapharca broughtonii in order to examine if organotin compounds, which are known to induce reproductive abnormalities in gastropods, have the same affect on bivalves. The research was conducted during seven weeks in spring season through a field transplantation experiment in one reference area (Ra) and two organotin‐polluted areas (Opa) near a shipyard complex. Sex ratio in the Ra was 1:1.6 (female:male). Sex ratio in Opa I and Opa II were 1:0.49 and 1:1.03, respectively, illustrating slightly higher proportion of females. Gonad activity exhibited a sequence of Opa II>Ra>Opa I. Intersex individuals of 3.33% (n=4/120) were confirmed in Opa. Intersex gonads were observed only in females. The results show that organotin compounds caused reproductive disruption in Scapharca broughtonii.

The rock shell (Thais clavigera) has attracted interest due to high frequency of imposex induced by endocrine disrupting chemicals (EDCs) in its natural populations. Oxidative stress is one of the mechanisms of action of EDCs. Glutathione S-transferases (GSTs) play an important role in antioxidant defense protecting the cells from oxidative stress. So far, there is no information on antioxidant defense or detoxification genes from T. clavigera. We cloned the full length cDNA sequence for a Mu-class of GST gene from T. clavigera (Tc-GSTM) and purified recombinant Tc-GSTM protein by bacterial expression. The deduced amino acid sequence of Tc-GSTM exhibited 45 to 66% identity with other Mu-class GSTs. Real-time RT-PCR analysis showed highest expression of Tc-GSTM in gill, while reproductive organs showed low expression. The biochemical characteristics of purified recombinant Tc-GSTM were typical, and thus Tc-GSTM showed highest specific activity for the universal GST substrate, 1-chloro-2,4-dinitrobenzene (CDNB). After exposure to prooxidant H(2)O(2), transformed Escherichia coli containing Tc-GSTM showed higher survival rate compared to control bacteria without expressed Tc-GSTM. The present study reveals a conserved antioxidant role for GSTM in rock shells, and the tissue-specific differences in Tc-GSTM transcripts would partly reflect vulnerability of reproductive organs to chemically induced oxidative stress.

This study estimated response of water duality and pollutant behavior according to the discharge and reuse of treated wastewater by three-dimensional eco-hydrodynamic model, and suggest plan that water quality management and environmental restoration in the coastal area including urban stream of Yeosu, Korea. Dispersions of low-saline water and COD by treated wastewater loads (design facility capacity, about ) were very limited in near of effluent site. Nutrients, however, increase compared to the other water quality factors, especially total nitrogen was very sensitive to input loads. When reuse some of treated wastewater to Yeondeung stream, nitrogen was big influence on estuarine water quality. Although current characteristics of treated wastewater such as discharge and water quality were negligible to the change of marine environment, effluent concentration of COD, TN and TP, especially 40% of TN, are reduced within the allowable pollutant loads for satisfy environmental capacity and recommended water duality criteria. Also, controls of input point/non-point sources to Yeondeung stream and base concentration of pollutants in coastal sea itself are very necessary.

The types, quantities, and distribution of marine litter found on the sea bed of the East China Sea and the South Sea of Korea are surveyed. Surveys were evaluated using bottom trawl nets during 1996–2005 cruises. Mean distribution densities were high in coastal seas, especially in the South Sea of Korea offshore from Yeosu, with 109.8 kg km −2 , and low in the East China Sea, with densities of 30.6 kg km −2 . Fishing gear, such as pots, nets, octopus jars, and fishing lines, accounted for about 42–72% and 37–62% of litter items in the East China Sea and the South Sea of Korea, respectively, whereas the contributions of rubber, vinyl, metal, plastic, glass, wood, and clothing were below 30% mainly. Rope and drum composition fluctuated greatly, between 54% and 0%. Eel and net pots dominated the marine debris of the South Sea of Korea, and some vinyl, plastics, and fishing gear made in Korea, China, and Japan were collected in abundance in the East China Sea. Fishing gear was probably discarded into the sea, deliberately or inadvertently, by fishing operations. A comprehensive joint approach by Korea, China, and Japan is needed for the continuous monitoring of input sources, the actual conditions, and the behavior of marine litter for protection against litter pollution and fisheries resource management in this area.

Summary Porcine enteric calicivirus (PECV) shares morphological and genetical similarities with Sapoviruses (SVs), which are the leading cause of epidemic, non‐bacterial gastroenteritis in children worldwide. The aim of this study was to identify the prevalence of PECV infection in pig farms in Korea, and to compare the evolutionary inter‐relationships between Korean PECVs and other caliciviruses. Among 102 diarrhoeic faecal samples of sucking (n = 50) and weaned (n = 52) piglets from 31 different farms in Korea, five samples (4.9%) were detected positive by reverse‐transcriptase polymerase chain reaction (PCR), but nine (8.8%) by nested‐PCR. Furthermore, we found that Korean PECVs are closely related to SVs.

Phytoestrogens and organochlorine pesticides in the diet of laboratory animals are a possible source of interference in bioassays that assess estrogenic activity. In the present study, we investigated the levels of dietary phytoestrogens, organochlorine pesticides and the estrogenic activity of various diets for an experimental fish and discuss the potential contribution of these substances to estrogenic activity, in comparison with those used in previous studies. After hydrolysis with β-glucuronidase, genistein and daidzein were detected in all of the diets, and there were no significant differences in the contents of these substances among present and previous investigations. In addition, organochlorine pesticides, such as hexachlorobenzene (HCB), β-benzene hexachloride (β-BHC), γ-BHC, trans-nonachlor, and/or endrin, were detected in most fish diets. All of these diets exhibited higher levels of activation of β estrogen receptors than with α estrogen receptors in an in vitro yeast-based bioassay. These results indicate that phytoestrogens, such as genistein and daidzein, were the main substances contributing to the estrogenic activity of the diet. Moreover, some diets may exert estrogenic activity in in vivo tests, indicating the necessity for more careful selection of the feeding diet and measurement of estrogenic substances when performing routine screening assays for endocrine-disrupting chemicals., Journal of Health Science v.51(2) p.212-219, 2005

This study estimated the appropriate pollutant load reduction from point sources in Kwangyang Bay, Korea, using an eco-hydrodynamic model. The total chemical oxygen demand (COD), nitrogen (TN), and phosphorus (TP) loads from rivers and ditches that provide input to the bay were approximately 2.8x10(4), 2.5x10(4), and 5.9x10(2) kg day-1, respectively. Wastewater discharge from industrial complexes was the greatest contributor to pollutant loads in the inner part of the bay. COD values in the inner part of the bay were greater than 3.0 mg l-1, and exceeded Korean seawater quality grade III limits. A residual current was simulated, using a hydrodynamic model, to have a slightly complicated pattern in the inner part of the bay, ranging from 0.001 to 8 cm s-1. In the outer part of the bay, the simulated current flowed out to the South Sea with a southward flow at a maximum of 15 cm s-1. The results of the ecological model simulation of COD levels showed high concentrations, exceeding 4 mg l-1, in the southwest of the Myodo, an area of wastewater discharge, and lower levels, approaching less than 1 mg l-1, closer to the outer part of the bay. Engineering countermeasures to reduce the organic and inorganic material loads from point sources by more than 45% were required to keep the COD levels below 2 mg l-1.

Objective To develop a rapid and sensitive method for the detection of canine distemper virus (CDV) by nested PCR using clinical specimens. Design A nested PCR was developed, compared to a one-step RT-PCR and validated. ProcedureTwo sets of specific primers for a one-step RT-PCR and a nested PCR, targeting a 640 bp fragment and a 297 bp fragment, respectively, were selected from the highly conserved region of the nucleocapsid protein (NP) gene of CDV. The nested PCR and the one-step RT-PCR were used to amplify a part of the CDV NP gene of a CDV vaccinal strain and samples of urine, blood, nasal discharge and saliva from 29 dogs suspected of suffering CD. Results Both the one-step RT-PCR and the nested PCR reacted with the CDV vaccinal strain, but not with canine parvovirus. The expected 640 bp fragment of the NP gene was detected in 11/22 (50.0%) blood, 10/20 (50.0%) urine, 5/25 (20.0%) saliva and 6/27 (22.2%) nasal swab samples by one-step RT-PCR, whereas the nested PCR amplified an expected 297 bp fragment of the NP gene in 18/22 (81.8%) blood, 15/20 (75.0%) urine, 14/25 (56%) saliva and 19/27 (70.3%) nasal swab samples. Conclusion The nested PCR detected CDV in blood, urine, nasal swab and saliva more frequently than did the one-step RT-PCR. Therefore, this assay should be a useful aid to ante-mortem diagnosis of CDV infections in dogs.

Toxicity and persistence of perfluorinated alkyl substances (PFASs) in human have raised considerable concern and several biomonitoring studies throughout the world reported the widespread occurrence of these compounds in human tissues. However, information regarding influence of geographic, lifestyle and demographic factor on PFAS levels in human blood tissues is limited. In this study, whole blood samples collected in 2006–2007 from 319 donors from suburban Seoul (Suwon and Yongin), Busan and Yeosu in Korea were analyzed for perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorohexane sulfonate (PFHxS) and perfluorooctane sulfonamide (PFOSA). Blood donors classified into seven age groups with ages ranging from 8 to 82 years, and different lifestyles and socio-economic status. PFOS (median = 4.15 ng/mL) was found at the highest concentration with a maximum concentration of 59.1 ng/mL. The concentrations of other PFASs were in the decreasing order of; PFOA (median = 1.30 ng/mL) > PFNA (median = 0.85 ng/mL) > PFHxS (median = 0.47 ng/mL) > PFOSA (median = 0.12 ng/mL). Geographical differences in the concentrations of five target PFASs were found. Significant positive relationships between PFAS concentrations and the age of the donors were found. Gender-related differences were found in the concentrations of PFOA, PFNA, PFHxS and PFOSA. No association was found between PFAS levels and several lifestyle factors and socio-economic status which included drinking habit, furniture/carpet in an indoor environment and monthly income. Occupation was an important determinant for PFNA and PFHxS concentrations in the whole blood. Except for PFOSA, significant associations were noted between PFASs concentrations and smoking habit. The results of this study provide information for further public health monitoring and safety management for PFASs in Korea.

Acute toxicity tests of tributyltin (TBT) and triphenyltin (TPT) were conducted on hte larvae of the rock shell, Thais clavigera, the disk abalone, Haliotis discus discus and the giant abalone, Haliotis madaka. For the rock shell larvae, the LC50 values (based on the nominal concentrations) were 8.4 μg (24 h) and 5.6 μg (48 h) TBT/IL; 8.6 μg (24 h) and 4.6 μg (48 h) TPT/L. For the disk abalone larvae, the 48 h LC50 values were 5.4 μg TBT/L and 1.4 μg TPT/L. For the giant abalone larvae, the LC50 values were 3.9 μg (24 h) and 1.2 μg (48 h) TBT/L; 2.4 μg (24 h) and 1.5 μg (48 h) TPT/L. Some effects on swimming behavior (e.g. unusual swimming behavior or low swimming activity) and irregular movement of cilia due to atrophy of velum compared to that in the control, as well as stripping out of the larvae from the shell, were observed even at lower concentrations than the LC50 values. From these experimental results and actual organotin concentrations in Japanese inshore waters, TBT pollution may have adversely affected the recruitment of the rock shell, the disk abalone and the giant abalone in heavily polluted areas.

We histologically examined normal differentiation and development of genital tract and gonad in the ivory shell Babylonia japonica (Buccinidae) to determine whether the formation of male-type genitalia in imposex-exhibiting females mimics the normal development of male genitalia in prosobranch gastropods. We used a wild-caught 2-year-old specimen and laboratory-reared juveniles aged 0–24 months. Gonad differentiation was unclear before age 14 months, but progressed after 16 months. Both sexes had complete genital tract and mature gonad at 20 months. However, differentiation and development occurred earlier in females than in males. Development of genital tract preceded gonad differentiation. Vas deferens morphogenesis in males resembled that in imposex-exhibiting females. These findings help to understand the morphogenesis of genital tract and gonad in prosobranch gastropods and will contribute to more in-depth studies of the mode of action of organotin compounds such as TBT and TPhT in imposex development in female prosobranch gastropods.

Bisphenol A (BPA) is an industrial chemical used in the manufacture of polycarbonate plastics and epoxy resins. Due to the potential of this compound to disrupt normal endocrinal functions, concerns over human exposure to BPA have been raised. Although several studies have reported human exposure to BPA in Western nations, little is known about exposure in Asian countries. In this study, we determined total urinary BPA concentrations (free plus conjugated) in 296 urine samples (male/female: 153/143) collected from the general population in seven Asian countries, China, India, Japan, Korea, Kuwait, Malaysia, and Vietnam, using high-performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS). On the basis of urinary BPA concentrations, we estimated the total daily intake. The results indicated that BPA was detected in 94.3% of the samples analyzed, at concentrations ranging from0.1 to 30.1 ng/mL. The geometric mean concentration of BPA for the entire sample set from seven countries was 1.20 ng/mL. The highest concentration of BPA was found in samples from Kuwait (median: 3.05 ng/mL, 2.45 μg/g creatinine), followed by Korea (2.17 ng/mL, 2.40 μg/g), India (1.71 ng/mL, 2.09 μg/g), Vietnam (1.18 ng/mL, 1.15 μg/g), China (1.10 ng/mL, 1.38 μg/g), Malaysia (1.06 ng/mL, 2.31 μg/g), and Japan (0.95 ng/mL, 0.58 μg/g). Among the five age groups studied (≤ 19, 20-29, 30-39, 40-49, and ≥ 50 years), the highest median concentration of BPA was found in urine samples from the age group of ≤ 19 years. There was no significant difference in BPA concentrations between genders (male and female) or domicile of residence (rural and urban). The estimated median daily intakes of BPA for the populations in Kuwait, Korea, India, China, Vietnam, Malaysia, and Japan were 5.19, 3.69, 2.90, 2.13, 2.01, 1.80, and 1.61 μg/day, respectively. The estimated daily intake of BPA in the seven Asian countries was significantly lower than the tolerable daily intake recommended by the U.S. Environmental Protection Agency. This is the first study to document the occurrence of and human exposure to BPA in several Asian countries.

The characteristics of the development of male genitalia (penis and vas deferens) in imposex-exhibiting female rock shells, Thais clavigera, were histologically examined using specimens from a wild population and tributyltin (TBT)-exposed females in the laboratory. A variety of vas deferens morphogenesis patterns were observed in wild female T. clavigera, and the characteristics were summarized. The immature vas deferens at an initial stage, however, was only observed beneath or behind the penis, and no vas deferens was observed close to the vaginal opening (i.e., vulva) of the capsule gland in TBT-exposed females, which was different from the characteristics of vas deferens formation observed in wild females. Taking into consideration both the observed results from wild female specimens and from TBT-exposed females in the laboratory, the vas deferens sequence (VDS) index for T. clavigera was proposed as VDS 1-6.

Concentrations of organotin compounds (butyltins and phenyltins) were determined in gonad, accessory sex organs, penis, digestive gland, kidney, radula with sac, oesophagus with crop, stomach, hypobranchial gland, rectum, mantle, osphradium, ctenidium, heart, salivary gland, head ganglia and muscle of imposex-exhibiting female and male rock shells (Thais clavigera), by gas chromatography with flame photometric detection (GC-FPD). Different tissue distributions were observed between butyltin and phenyltin compounds. More than 1000 ng TBT/g wet wt. were observed in ovary, digestive gland, kidney, heart, ctenidium, osphradium, stomach, head ganglia and penis, of both imposex-exhibiting females and males. More than 1000 ng TPT/g wet wt. were found in almost all tissues of both sexes. Approximately one-third or more of total TBT was accumulated in the digestive glands of both females and males, respectively. Meanwhile, approximately 40-50% and one-half of total TPT accumulated in the digestive glands of females and males, respectively.