• Membrane Journal
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• v.17 no.2
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• pp.112-117
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• 2007

The application of membrane bioreactors for the depuration of wastewater coming from the washing of mineral oil storage tanks is described. Microfiltration hollow-fibre membranes were used in the submerged configuration. Filtration tests were carried out with a biomass concentration of about 15 g/L in order to assess the critical flux of the hollow fibre membrane used. Then particular care was taken in carrying out the performance runs in the sub-critical flux region. The reactor performance was very high, with removal efficiencies ranging between 93% and 97% also when the concentration of hydrocarbon was very high. Some kinetic parameters for the COD and the hydrocarbon removal were estimated.

• Fisheries and Aquatic Sciences
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• v.14 no.3
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• pp.210-217
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• 2011

Olive flounder, Paralichthys olivaceus were exposed to waterborne Cu (control, 50, 80, 150, and 320 ${\mu}g$/L) for 30 days and then depurated for 20 days to investigate the effects of waterborne Cu exposure on growth, accumulation, and elimination. The weight-specific growth rate was significantly negatively related to waterborne Cu concentrations at 150 and 320 ${\mu}g$/L. The order of Cu accumulation in different tissues of exposed fish was liver>intestines>gills>kidneys>muscle, suggesting that the liver is more important than other tissues for the storage of Cu in olive flounder. The accumulation factor for the gills, intestines, liver, and muscle increased with increasing exposure time, and accumulation was negatively related to exposure concentration for the gills, kidneys, and muscle. Cu concentrations in the gills, intestines, and liver continuously decreased for 20 days of depuration. The fastest elimination rate occurred in the intestines at all exposure concentrations, and the order of Cu elimination in the different tissues was intestines>liver>gills.

• The Korean Journal of Malacology
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• v.21 no.1
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• pp.13-17
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• 2005

In this study, the influence of water temperature and salinity on sand ejection of Manila clams, Ruditapes philippinarum, was investigated. The result showed that, under different water temperature, the highest quantity of sand ejection was at $20^{\circ}C$, the value of which was 0.091 g, while the smallest one was only 0.058 g at 0$^{\circ}C$. The highest releasing rate, 95.79%, could be seen in $20^{\circ}C$ group, while $0^{\circ}C$ group was the lowest one, 85.29%. Under different salinity, 30 psu group had the highest value, 0.057 g, and 0 psu (freshwater) group was the lowest one, only 0.026 g. At the same time, the highest releasing rate appeared at 25 psu, which was 90%. 0 psu group was the lowest one in releasing rate, 60.47%. According to these results, we recommend that the clams should be placed into the clear seawater with about 25 psu of salinity at near $20^{\circ}C$ to let the clams perform the self-depuration. Better quality of clams containing less impurity in the aquaculture and commerce could be obtained from this pre-treatment.

• Korean Journal of Ecology and Environment
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• v.44 no.4
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• pp.317-326
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• 2011

With its recent advances, nanotechnology is now being applied to various areas. Despite the benefits of nanoparticles, their risk in the environment has caused controversy, which is now becoming an international issue. Nanoparticles can easily infiltrate into cells, accumulate in biota, and may cause adverse effects in the levels of molecules, cells and organisms, and in the community. If nanoparticles are released into the environment, they can be transferred to organisms in the ecosystem, and eventually to the human body through the food chain. In this study, the research trend of the trophic transfer of nanoparticles in the food chain was investigated. Although a few investigations have been conducted regarding this topic, the trophic transfer of nanoparticles is becoming a significant issue in the area of nanotoxicology due to the potential risk to humans via the biomagnification process. While previous studies have demonstrated evidence of the trophic transfer of nanoparticles intensive future studies are needed to provide further information on the properties of nanomaterials, the exposure media, and the in vivo mechanisms such as uptake, accumulation, and depuration.

• Fisheries and Aquatic Sciences
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• v.7 no.3
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• pp.115-121
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• 2004

Experiments were carried out to investigate Cd accumulation, elimination and cell response in juvenile rockfish (Sebastes schlegeli) exposed to sub-chronic dietary Cd (0, 0.5, 5, 25 and 125 mg/kg) for 60 days and depuration periods of 30 days. Cd accumulation in the kidney of cock fish increased with exposure periods and concentrations for the 60 days of dietary Cd exposure. After the end of the dietary Cd exposure, Cd accumulation values in the kidney were $52.9{\pm}9.94\;{\mu}g/g$ and $90.6{\pm}15.7\;{\mu}g/g$ for those exposed to 25 mg/kg and 125 mg/kg Cd, respectively. The accumulation factors increased with the exposure period in the kidney. Cd elimination in the kidney of rockfish did not vary significantly and remained constant after the cessation of the dietary Cd exposure. In the primary exposure periods, the effect of kidney tissue in the rockfish exposed to dietary Cd was observed the swelling of capillary of the glomerulus. In addition, there was also hydropic swelling within the pyknotic nuclei, some of hyaline droplet accumulation and the microvilli showed a positive reaction to alcian blue in the tubular cells. While exposure time and concentrations were increased, there was a lot of hyaline droplet accumulation and the microvilli showed a positive reaction to alcian blue in the tubular cells. Fused renal tubule and its necrosis were observed after 60 days at l25 mg/kg.

• Fisheries and Aquatic Sciences
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• v.5 no.4
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• pp.263-270
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• 2002

The Pacific oysters, Crassostrea gigas, were stressed with different concentrations of benzo(a) pyrene and depurated to determine the hemocyte lysosomal membrane stability and hydrolytic enzymatic activity as a biomarker candidate to the chemical, using NRR (neutral red retention) and API ZYM System, respectively. The membrane damage measured as NRR decrease was significant with the increase of chemical concentration and exposure time (P<0.05), providing a possible tool for biomarker. Interestingly, the control showed intrinsic stress probably due to captive life in the laboratory, and a recovering trend was also found during the depuration. The benzo(a)pyrene-exposed oysters showed increased enzyme activities in alkaline phosphatase, esterase (C4), acid phosphatase, naphthol-AS-BI-phospho­hydrolase, $\beta$-galactosidase, $\beta$-glucuronidase, and N-acetyl- $\beta$-glucosaminidase. Of them, only two enzymes, acid phosphatase and alkaline phosphatase, showed some potential available for the generation of enzymatic biomarker in the oyster. The results are suggestive of the potential availability of the cellular and enzymatic properties as a biomarker. However, considering that a robust biomarker should be insensitive to natural stress coming from normal physiological variation, but sensitive to pollutants, a concept of intrinsic stress the animal possesses should be taken into consideration. This reflects the necessity of further research on the intrinsic stress affecting the cellular and enzymatic properties of the chemical­stressed oysters prior to using the data as a biomarker.

• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.37-42
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• 2001

Zebrafish(Brachdanio rerio)를 실험어류로 하여 methidathion 과 phosalone의 생물농축계수(bioconcentration factor : BCF)와 배설속도상수 (depuration rate constant) 및 LC$_{50}$를 측정하였다. Methidathion의 24, 48, 72, 96시간 LC$_{50}$는 각각 28.34, 35.98, 24.43, 22.03 mg/$\ell$로 측정되었다. Methidathion 0.22 mg/$\ell$(고농도)와 0.022 mg/$\ell$(저농도)에서 어류 체내에서의 농축정도는 두 농도군에서 각각 12시간 이후에 정류상태에 도달하여 72시간동안 거의 일정하였고, BCF값도 12시간에서 72시간 사이에 고농도와 저농도에서 8.72(n=4)와 11.25(n=4)로 조사되었다. 배설속도상수는 고농도와 저농도에서 6시간 이내에 모두 배설되어 배설속도상수를 구할 수 없었다. Phosalone의 24, 48, 72, 96시간 LC$_{50}$는 각각 3.76, 2.43, 1.86, 1.05 mg/$\ell$로 측정되었다. Zebrafish 체내에서의 농축정도와 BCF값은 고농도(0.01 mg/$\ell$)에서 12시간 이후에 정류상태에 도달하여 72시간동안 거의 일정하였고, BCF값은 12시간에서 72시간 사이에 48.88(n=4)로 측정되었다. 저농도(0.001 mg/$\ell$)에서는 실험 전기간동안 zebrafish 체내에서 phosalone이 검출되지 않아 BCF값을 산출할 수 없었다. Zebrafish 체내에서 phosalone(고농도)의 배설속도상수와 반감기를 구하기 위하여 6,12시간의 배설실험 결과 각각 0.17$hr^{-1}$과 4.01 시간이었다. Methidathion과 phosalone의 BCF값은 phosalone이 methidathion 보다 약 5배 정도 높게 나타났으며, 농약의 배설속도는 phosalone이 methidathion보다 빨랐다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.3
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• pp.179-183
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• 2001

Shortnecked clam, Ruditapes philippinarum, is one of the very important shellfish produced in south-western coast of Korea. But it's ready to be polluted and have sand in flesh because it mainly inhabit in silt at the inside of coastal area. This study was carried out to obtain informations about the elimination of sand in shortnecked clam harvested from western coast of Korea. During rearing shortnecked clams in water tank, the elimination rates of sand from them at 6, 13, 23, $28^{\circ}C$ were 59.0, 88.2, 97.9, $96.1^{\circ}C$ after 48 hours, respectively. The sand was eliminated above $95^{\circ}C$ from the shellfish at 32,9 to $40\%_{\circ}$ of salinity after 48 hours. But the sand elimination from them was incomplete and inconsistent at 10 to 20 of salinity. The sand was eliminated rapidly at pH 1.9 to 9.0 however, its elimination was not effective at neutral or acidity range, It was found that the sand elimination was most effective at $23^{\circ}C, 35\%_{\circ}$ salinty and pH 9.0. Reasonable flow rate for sand eliminate in shortnecked clam was above 150 L/min./shellfish $m^3$ under both 3,000 and 4,000 L/shellfish $m^3$, and above 100 L/min,/shellfish $m^3$ under both 6,000 and 8,000 L/shellfish $m^3$ in water tank.