• Journal of Environmental Science International
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• v.5 no.3
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• pp.329-335
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• 1996

This project studies marine Vibrio vulnificus in oysters in the marine environment and attempts to correlate this bacteria's presence within various environmental parameters; we design this study to determine how different storage temperatures affect the survival of V. vuinficus in oysters and whether V. vulnificus is able to persist in oysters after exposure to UV light-disinfected seawater. Experimental depuration systems consist of aquaria containing temperature-controlled seawater treated with UV light and 0.2 ㎛ pore size filtration. Results showed that depuration at temperatures higher than 25℃ caused V. vuinificus counts to increase in oysters. Throughout the process, depuration water contained high concentrations of U vuinificus indicating"that the disinfection properties of UV radiation and 0.2 ㎛ pore size filtration were less than 어e release of V. vuinificus into seawater, In contrast, when depuration seawater was maintained at 10℃, the numbers of V. vuinificus were very little and multiplication in oysters was inhibited.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.453-461
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• 2009

Killifish (Oryzias latipes) were exposed to an organophosphate pesticide, pirimiphos-methyl, in a flow-through system to determine the bioconcentration factor (BCF) following GLP (Good Laboratory Practice). This study was conducted at two different concentrations (1 and $10\;{\mu}$g/L) of $^{14}C$-labeled pirimiphos-methyl for 28 days uptake and 14 days depuration according to the OECD 305 test guideline. The $BCF_{ss}$ for total radioactive residues in whole fish were 1,251 and 1,277 for low and high concentrations, respectively. The $BCF_k$ based on the uptake and depuration rate constants were 1,200 for both low and high concentrations. During the depuration phase, the accumulated test substance was rapidly depurated from fish. Greater than 95% of the residue at steady-state was depurated after 2 days. Although the measured BCF values were high, pirimiphos-methyl could be evaluated as a low risk from bioaccumulation by aquatic organisms due to the short depuration period and low amount of bound residue (1.5%). We suggest that in evaluating bioaccumulation, not only the BCF should be considered, but also depuration time and bound residue in aquatic organisms give an indication of the potential environmental risks.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.842-850
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• 2020

The objective of this study was to evaluate the effect of the depuration process (artificial seawater sterilization using UV light) for extending the shelf life of raw oyster Crassostrea gigas and maintaining food quality. To confirm the effects of depuration, microbiological (viable cell count) and several physiochemical analyses (pH and glycogen levels in shucked oyster and pH, soluble protein, and turbidity in filling water) were carried out during the storage of raw oysters. The results showed that depuration could effectively extend the shelf life (2-3 days) of raw oysters with minimal change in food quality, including pH and glycogen content. Thus, the depuration process proposed in this study could successfully be applied to processing practices for other shellfish to extend their shelf life and contribute to the management of seafood safety issues.

• Journal of Environmental Health Sciences
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• v.23 no.2
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• pp.72-82
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• 1997

This study was performed to investigate the effect of co-existence of BPMC, carbaryl and chlorothalonil on the short-term bioconcentration factor in Carassius auratus(goldfish). The fishes were exposed to the combined treatment of BPMC, carbaryl and chlorothalonil (0.05 ppm+0.05 ppm+0.005 ppm, 0.05 ppm+0.05 ppm+0.010 ppm, 0.05 ppm+0.10 ppm+0.005 ppm, 0.10 ppm+0.05 ppm+0.005 ppm, 0.10 ppm+0.10 ppm+0.005 ppm) for 3 and 5 days, respectively. BPMC, carbaryl and chlorothalonil in fish and in test water were extracted with n-hexane and acetonitrile. GC-ECD was used to detect and quantitate BPMC, carbaryl and chlorothalonil. 3-day and 5-day bioconcentration factors(BCF$_3$ and BCF$_5$) of each pesticide were calculated from the quantitation results. The depuration rate of each pesticide-from the whole body of fish was determined over the 72-h period after combined treatment.The results were as follows: BCF$_3$ values of BPMC were 4.163, 4.011, 4.122, 4.750 and 4.842 when the concentration of BPMC+ carbaryl+chlorothalonil in combined treatment were 0.05 ppm+0.05 ppm+0.005 ppm, 0.05 ppm+0.05 ppm+0.010 ppm, 0.05 ppm+0.10 ppm+0.005 ppm, 0.10 ppm+0.05 ppm+0.005 ppm and 0.10 ppm+ 0.10 ppm+0.005 ppm. BCF$_5$ values of BPMC were 3.465, 3.270, 3.472, 3.162, 4.227 and 4.157, respectively, under the above conditions. While BCF$_3$ values of carbaryl were 4.583, 4.642, 4.571, 3. 637 and 3.529, respectively, and BCF$_5$ values of carbaryl were 3.932, 3.797, 3.843, 4.293 and 4.132, respectively, under the conditions. While BCF$_3$ values of chlorothalonil were 2.024, 3.532, 2.213, 2.157 and 2.271, respectively, and BCF$_5$ of chlorothalonil were 6.712, 7.013, 6.457, 6.694 and 6.597, respectively, under the conditions. Depuration rate constants of BPMC were 0.019, 0.018, 0.020, 0.022 and 0.021 when the concentration of BPMC+carbaryl+chlorothalonil in combined treatment were the same as above. And depuration rate constants of carbaryl were 0.030, 0.029, 0.030, 0.029 and 0.031, respectively, under the same condition of pesticide mixtures. While depuration rate constants of chlorothalonil were 0.004, 0.004, 0.003, 0.004 and 0.003, respectively, under the same condition. It was observed that no significant differences of BCFs and concentrations of the compounds in fish extracts, test water between combined treatment and single treatment. It was considered that no appreciable interaction at experimental concentrations was due to low concentrations, near environmental level, 0.005-0.1 ppm. Coexistence of BPMC, carbaryl and chlorothalonil had no effect on depuration rate of each pesticide and depuration rate of chlorothalonil was investigated 1/8 and 1/6 slower than those of carbaryl and BPMC in combined treatment. It is similar result in comparison with single treatment. Therefore, it is considered that the persistence of chlorothalonil in fish body would be higher than those of carbaryl and BPMC.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.255-259
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• 1979

Depuration of extraneous substances such as bottom deposit, feces and coliforms from live oyster has been studied. Coliform accumulation of bottom cultured oysters was much higher than that of raft or long line cultured oysters. When the depuration tank designed in this study was adopted, the depuration rate could be diminished to about $50\%$ within one hour treatment. Tho most effective conditions of the tank water for depurating live oysters wer $22^{\circ}C$ in temperature, 8.80 in pH and below about 2 ppm of residual chlorine concentration.

• Journal of Aquaculture
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• v.10 no.2
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• pp.189-197
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• 1997

A series of short (8 hours) and long term (96 hours) exposure studies was conducted on a laboratory scale to evaluation (1) the threshold concentrations of petroleum hydrocarbon in seawater which can lead to tainting problems in yellow tail (Seriola quinqueradiata) and (2) the time to recover (depuration period) once the tainting has occurred. The water-soluble fraction (WSF) of crude oil was prepared by stirring the oil with cold seawater. The main component of the WSF were low-boiling aromatics, although these were only al small proportion of the starting oil. From the sencory evaluation it was concluded that the threshold hydrocarbon levels in seawater which will impart a taint in yellow tail fillets within a 8-hour exposure period (short exposure period) are in the range of 0.4 to 1.0 ppm and within a 96-hour exposure period (long exposure period) are in the range of 0.2 to 0.5 ppm. Depuration trials were carried out with WSF from crude oil. The fish were exposed for 48 hours to concentration of 2.5 ppm hydrocarbons. After 48-hour exposure period, the fish were allowed to depurate in fresh, uncontaminated seawater. Depuration time for these fish was 10 days. The taste panelists were able to detect the contaminated fillets very easily while the depurated fish could not be distiguished from the control.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.2
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• pp.109-115
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• 2016

The efficacy of depuration following growing area translocation for the defecation of norovirus was evaluated under experimental conditions using oysters Crassostrea gigas previously subjected to bioaccumulation of this virus at a waste treatment plant discharge site. Three trials were assayed in an open experimental system with a commercial oyster farm located in a shellfish growing area approved by the Korean Shellfish Sanitation Program. Real-time reverse-transcription polymerase chain reaction (RT-PCR) was used to quantify viruses in the digestive glands of oysters. The final viral loads in oysters after 12 days remained under the detection limit (10 copies/g digestive gland) of the real-time RT-PCR. This reduction trend showed two-phase removal kinetics, with an initial slow reduction or slight increase in viruses during the first 2 days of depuration and subsequent stabilization with 0.12 to 2.64 log unit norovirus copies/g digestive gland per 2 days of depuration for the remaining time.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.1
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• pp.11-16
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• 2012

In coastal areas that are affected by continuous, seasonal or occasional pollution sources, bivalves accumulate biological contaminants such as pathogenic bacteria. We investigated the effect of natural seawater relaying and electrolyzed seawater depuration on the bacteriological quality of artificially contaminated oysters Crassostrea gigas and short-necked clams Ruditapes philippinarum to suggest an alternative method of shellfish sanitation control.When artificially contaminated oysters and short-necked clams (fecal coliform level 1,700 MPN/100 g) were relayed into a sea area of safe bacteriological water quality, the fecal coliform level dropped to below 110 MPN/100 g after 1 day. The bacteriological quality of oysters and short-necked clams that are contaminated at a fecal coliform level of 1,700 MPN/100 g could be improved, and become appropriate for raw consumption by a single day relay under proper environmental conditions. When artificially contaminated oysters (fecal coliform level 330 MPN/100 g) were depurated with electrolyzed seawater, 94% of fecal coliform was eliminated after 12 h and fecal coliform was undetectable after 24 h. After 24 h depuration with electrolyzed seawater, the fecal coliform level of short-necked clams with initial fecal coliform of 2,400 MPN/100 g was below 20 MPN/100 g. However, the fecal coliform level of short-necked clams with initial fecal coliform of 17,000 MPN/100 g was relatively high, at 790 MPN/100 g, even after 24 h of depuration with electrolyzed seawater, because of the repeated cycle of excretion and accumulation of fecal coliform in shellfish tissue under the closed depuration environment. Such natural seawater relaying and electrolyzed seawater depuration can be restrictively applied to improve or secure the bacteriological quality of oysters and short-necked clams in accordance with safety levels for bivalves for raw consumption.

• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.108-118
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• 2001

This study was performed to investigate the bioconcentration of IBP, methidathion and piperophos. The BCFs(bioconcentration factor), depuration rate constants for three pesticides in zebrafish(Brachydanio rerio) were measured by OECD guideline 305. The concentration of test pesicides were one-hundredth and one-thousandth concentration of 96-hrs L $C_{50}$ in accordance with OECD guideline 305. The results obtained are summarized as follows: The average BCF values of IBP were 5.31(n=4) and 7.30(n=4) at one-hundredth and one-thousandth concentration of 96-hrs L $C_{50}$ . The average BCF values of methidathion were 8.72(n=4) and 11.25(n=4), the average BCF values of piperophos were 34.30(n=4) and 42.60(n=4). Depuration rate constants of IBP were 0.09( $h^{-1}$ ) and 0.08( $h^{-1}$ ), half-life of IBP were 7.70 and 8.66 at each tested concentration. The concentrations of IBP in zebrafish at low and high concentrations rapidly decreased after 12(0.243$\mu\textrm{g}$/g) and 12 hours(0.040$\mu\textrm{g}$/g). Depuration rate constants of methidathion were 0.40( $h^{-1}$ ), half-life of methidathion were 1.73 at one-hunderdth and of 96-hrs L $C_{50}$ , repectively. The concentrations of methidathion in zebrafish at high concentrations rapidly decreased after 6 hours(0.18 $\mu\textrm{g}$/g). Depuration rate constant of low concentration was no measured because methidathion in zebrafish was depurated in 6 hours. Depuration rate constants of piperophos sere 0.15( $h^{-1}$ ) and 0.44( $h^{-1}$ ), half-life of piperophos were 4.62 and 1.58 at each tested concentration. The concentrations of piperophos in zebrafish at los and high concentrations rapidly decreased after 12(0.26$\mu\textrm{g}$/g) and 6 hours(0.015 $\mu\textrm{g}$/g). It was suggested that high BCF of piperophos was due to high Kow(octanol-water partition coefficient). The possibility of bioconcenration was not likely to be high because of its $K_{DEP}$(depuration rate constant) in the evniroment. It was suggested that low BCF of methidathion showed lowest Kow as well as the most rapid $K_{DEP}$. Therefore, the possibility of bioconcentration was not occured in the enviroment. It was suggested that the BCF dtermined for IBP was lower than that of other pesticides due to high Sw(water solubility), show $K_{DEP}$. Therefore, IBP revealed little bioconcentration effect on in aquatic ecosystem.ystem.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.1
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• pp.44-48
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• 2003

Experiments were carried out to investigate the elimination of cadmium in tissues (gill, intestine, liver, kidney and muscle) of flounder, Paralichthys olivaceus, after sub-lethal Cd exposure (5, 50, 100 ${\mu}g/L$). During the depuration phase, Cd concentration in the gill decreased immediately following the end of the exposure period. The elimination rates at the end of depuration periods were $18\%$ for 50 ${\mu}g/L$ exposure and $70\%$ for 100 ${\mu}g/L$ exposure. Intestine showed fastest elimination rates of Cd at all concentration. At the end of the depuration period, the Cd concentration was similar to that in the control, Cd elimination in liver significantly decreased after 10 days of depuration period. After 20 days of depuration, the elimination rate was $66.20\%$ in the fish exposed to 50 ${\mu}g/L$ and $86.22\%$ in the fish exposed to 100${\mu}g/L$. The order of cadmium elimination in tissues were decreased intestine>liver${\geq}$gill>>kidney during depuration periods. In this study the gill, intestine and liver showed faster elimination rate of Cd in 50, 100 ${\mu}g/L$-Cd exposure concentration. After the end of the Cd exposure, the Cd concentration in the kidney slowly decreased or remained constant and the Cd concentration in the muscle slowly increased or remained constant.