• The Korean Journal of Malacology
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• v.27 no.4
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• pp.307-315
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• 2011

Digestibility index of 12 phytoplankton species were invested during the larval development sizes. Ingestible size of phytoplankton varied depending on larval sizes: Isochrysis galbana, I. aff. galbana, Pavlova lutheri, Chlorella ellipsoidea, Nannochloris oculata was ingested 94.2-99.7% all larval sizes. Cheatoceros calcitrans, C. gracilis and C. simplex could ingest over 90.0% after umbo stage (mean shell length $189.3{\pm}13.8{\mu}m$). Phaeodactylum triconutum, Dunaliella tertiolecta and Tetraselmis tetrathele could not ingested D-shaped larvae (shell length $65.0-100.0{\mu}m$) but ingested 97.3-99.7%, 43.3-99.3%, 48.5-99.3% after then larval stages, respectively. But Thalassiosira weissflogii was ingested 1.0-1.7% only at full grown stage. Over 50.0% ingestion cell size was D-shape stage larvae with smaller than mean $102.3{\mu}m$ in shell length could ingest phytoplankton with $4.6{\mu}m$ in both major and minor axis and up to $9.3{\mu}m$ in minor axis basis for larger than mean $158.3{\mu}m$ in shell length, respectively. At all larval stages, phytoplankton with larger than $10.0{\mu}m$ in both major and minor axis could not be ingested.

• Resources Recycling
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• v.6 no.3
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• pp.28-35
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• 1997

Adsorption properities of hcavy metals (Cd, Cu, Fe, Mn, Pb, Zn) and organic compounds (Trichloroethylene and T Tetrachroethy len려 on sh$\xi$1I( oyster and ark shell) were investigated using wat$\xi$r treatment matenals, The shell powder (m띠or C crystal structurc is calcium hydroxide) showed the preference adsorption for heavy metals in order of Mn > Zn > Fe > Cd > eu > P Pb. The high removal capacities of heavy metals arc helicved to be largely due to precipitation by foonation of metal c carhonat,잃 and hydroxides at high pH caused by the $Ca(OH)_2$ component of sl1ell, immobilizatIon of heavy metals in a solid I matrix by calcium‘ and fixation by insoluble organic materials in the oystcr and ark shell. The use of sh려I in water treatment h has the potential to bc benefIcial as a source of inexpensive matcrials‘ moreover, not only treatment of waste but also e environmcntal business including environmental-purification ceramics could be better off by utili낌ng high-valued waste and d developed puri'fication ceramics and media.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.185-192
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• 2010

The objective of this study was to investigate the effectiveness of stabilization for army firing range soil highly contaminated with Pb (total Pb: 29,000 mg/kg) using calcined waste oyster shells. The calcination was conducted to activate quicklime from calcite. In order to evaluate the effectiveness of calcination, both natural oyster shells (NOS) and calcined oyster shells (COS) were applied to the Pb contaminated soil. Stabilization was conducted by mixing the contaminated soil with oyster shell media at 5-20 wt% and cured for 28 days. Following 28 days of curing, Pb leachability was measured based on the Korean Standard Test method (0.1 N HCl extraction). The treatment results showed that the COS treatment outperformed the NOS treatment. All of the NOS treatments failed to meet the Korean warning standard of 100 mg/kg. However, the Pb concentrations were significantly reduced to 47 mg/kg and 3 mg/kg upon 15 wt% and 20 wt% COS treatments, respectively which passed the Korean warning standard. Moreover, -#20 mesh materials were more effective than the -#10 mesh materials in effectively reducing Pb leachability. The scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) results indicated that Pb immobilization was strongly linked to Al and Si.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.1
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• pp.52-57
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• 2005

Previous studies showed that shell meal fertilizer from the oyster farming industry could be a potential inorganic soil amendment to increase Chinese cabbage productivity and to restore the soil nutrient balance in upland soil (Lee et al., 2004). Herein, shell meal fertilizer was applied at rates of 0, 4, 8, 12, and $16Mg\;ha^{-1}$ to upland soil (Pyeontaeg series, Fine silty, Typic Endoaquepts) for Chinese cabbage cultivation. We found available phosphate increased significantly with shell meal fertilizer application, due to high content of phosphate ($1.5g\;P_2O_5\;kg^{-1}$) in the applied shell meal fertilizer. In addition, high pH of shell meal fertilizer contributed to increase available phosphate content by neutralization of acidic soil. Total and residual P contents increased significantly with increasing shell meal fertilizer application, but we could not find any tendency in organic and inorganic P fraction. Of extractable P fraction, water-soluble phosphorus (W-P) and calcium-bound P (Ca-P) contents increased significantly with increasing application level. By contrast, aluminum and iron-bound P (Al-P and Fe-P) decreased slightly with shell meal application. The present experiment indicated that shell meal fertilizer had a positive benefit on increasing available phosphate content in arable soil. And so the increased available phosphate by shell meal fertilizer may decrease phosphate application level and then reduce phosphorus loss in arable soil.

• 한국해양학회지
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• v.13 no.1
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• pp.35-43
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• 1978

Short-term acute toxicity of mercury, cadmium and copper to arkshell, Anadara broughtonii, and to oyster, Crassostrea gigas, was determinedby static bioassays from 20 May to 27 June in 1977. During the observations of the opening rate of the shell mercury was the most sensitive toxicant of the three toxic substances to the test animals and caused them to close their shellvalves together after being exposed to a mercury solution for an hour during the test. Opening rate to cadmium and copper increased gradually at the higher concentration. the 96hr-LC50 values for the test animals are 4.84mg/l for mercury and 1.86mg/l for cadmium, while the 72hr-LC50 value for copper is 0.31mg/l. the death rate of oysters for cadmium showed lower than that of the mercury and copper test solutions. The 96hr-LC50 values of mercury, copper and cadmium were 1.1mg/l, 2.54mg/l and 19.5mg/l, respectively. For oysters mercury was the most toxic substance, and cadmium was the least toxic one. the medium lethal time (LT 50) value decreased gradually at higher concentration of heavy metals. The LT 50 of 2mg/l was found within 96 hours ofr copper, 104 hours for mercury and 121 hours for cadmium. The lethal threshold concentrations for 7 days were found to be about 1mg/l for mercury and copper, and 2mg/l for cadmium.

• Korean Journal of Poultry Science
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• v.8 no.2
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• pp.55-68
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• 1981

Calcium and phosphorus are not only indispensable for the bone formation and body fluids equilibrium but also are major components of egg shell. It is nutritionally important, therefore, to investigate the metabolism of calcium and phosphorus and to search for optimum requirement of calcium and phosphorus and the availability of various sources of calcium an4 phosphorus by poultry. An attempt was made to review the nutrition of calcium and phosphorus in poultry diets. 1, Calcium and phosphorus have great interrelationship with vitamin D in their metabolisms. 2. Most of the plant-origin phosphorus are existing in phytic form and it leads to low availability when used in poultry rations, although calcium and phosphorus present in animal-origin or mineral supplements are highly available in general. 3. Calcium and phosphorus requirement from existing information indicated that 1.0% calcium and 0.7% phosphorus for broiler and egg-type chicks, and 3.5% calcium and 0.4% phosphorus for laying hen. 4. It has been recommended that calcium and phosphorus level should be increased when the feed intake was decreased or when the egg Production rate was higher or when the hens are old. 5. Mono-, ci-, tri-, calcium phosphate, calcium carbonate, bone meal, limestone and oyster shell u the most readily available among various sources of calcium phosphorus supplements. Soft rock phosphate, deflourinated phosphate and gypsum are somewhat inferior to the previous ones in bioavailability. 6. The effect of particle size of calcium supplements on egg shell quality and egg production rate is not yet clearly defined but recent works showed that oyster shell is more available when it was coarse and limestone is more available when it was fine in panicle. size. 7. Present data indicated that mixed feeding of oyster shell and limestone is superior to the single feeding of each on laying performance. 8. Significant interaction between phosphorus and sodium was observed, that is, excessive sodium decreased egg production in layer and body weight growth in broiler in the low phosphorus diets but increased them in the high phosphorus diets.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.1
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• pp.68-75
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• 2002

This study were observed to the conditions of organic pollution applying to tile environmental assessments based on macrobenthos around the raft culture ground which became an issue by organic matter input in Jinhae Bay. Three stations, mussel farm, oyster farm and the control station on which rarely culture activities were fixed and have analyzed to the sediment characteristics and macrobenthic communities. Muddy substrates between 6.0 and 6.60 on mean grain size have prevailed to the bottom layer in all stations. The highest organic matter content of 2.8% was observed to the mussel farm while the lowest one of 1.5% was recorded on the control area. As a total, 79 species from seven phyla were identified. Comparing to shell farms, the control station have composed to more diversified community structure. In the mussel and the oyster farm, opportunistic species, living in high organic contents area, Lumbrineris longifolia, Heteromastus. filiformis in polychaetes and Corophium sinense in amphipod were dominated. As results on environmental assessment, in spite of changing to the species composition and densities seasonally, the mussel farm have recorded only to moderately polluted condition.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.367-373
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• 2014

In order to investigate the impact of recycling agricultural wastes as feed for mealworm (Tenebrio molitor), we evaluated the replacing effect by the different level of tangerine shell, Chinese cabbage, king oyster mushroom (Pleurotus eryngii) and Enoki mushroom (Flammulina velutipes) substrates on wheat bran feed. Larval survival rate, larval weight, developmental period of larva, pupation rate and pupal weight were evaluated. In tangerine shell and Chinese cabbage replacement group, no replacing effects found. In all groups replacing by spent King oyster mushroom (Pleurotus eryngii) substrate, survival rate of larva was similar to that of control group but larvae weighed less than control group significantly. Developmental period of larva increases in the group of King oyster mushroom substrate replacement. Larval and pupal weight in Enoki mushroom (Flammulina velutipes) substrate by the level of 40 and 50%, replacement effect showed best results in successive breeding considering pupation rate. It is concluded that replacing 40 and 50% of Enoki mushroom (Flammulina velutipes) substrate is appropriate to substituted diet of Tenebrio molitor larvae.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.5
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• pp.685-690
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• 2021

Harmful shell-boring species of the genus Polydora (Polychaeta: Spionidae) were frequently reported from commercially important mollusk species in Korea, Japan and China. The traditional approach based on the morphological characteristics showed limitations for species discrimination among shell-boring species. Therefore, DNA barcoding was adopted to identify Polydora species using molecular markers. Two Polydora species (P. haswelli and P. hoplura) in abalone shells were reported from our previous molecular phylogenetic study. In this study, we additionally reported the presence of shell-boring Polydora haswelli in commercially sold shellfish. The taxon-specific cox1 marker used in this study successfully allowed the isolation of P. haswelli from cockle Scapharca subcrenata, mussel Mytilus galloprovincialis, oyster Crassostrea gigas and scallop Argopecten irradians. Polydora hoplura was not found in these shellfish species. The genetic variations were found on the intraspecific level of P. haswelli and the same genotype was also detected in different shellfish species. This result can provide information on a new host and accurate parasitic Polydora species. Moreover, this report can be used as the biodiversity data of Polydora species on the invasion and transition of harmful Polydora species in mollusk aquaculture farms.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.2
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• pp.90-100
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• 1975

The estimation of the pre-processing condition of oyster is of great importance for distributors and processors. This study was attempted to establish the basic data for evaluating the processing suitability of oyster, which is the most important shellfish for domestic use and export. The data were analysed by measuring the condition index, chemical composition and heavy metal content of oysters. In order to eliminate the manual work that has to be done on a tightly closed oyster shell and avoid shrinkage in the oyster meat which is attendant on the steaming process, chemical means to open oyster were examined. finding the method of pretreatment of polyphosphate for frozen oysters were attempted to improve the product quality. The prevention of undesirable color change of the canned oyster meat is another problem to solve. The important results are as follows : 1. The ratio of meat volume and meat weight to the holding capacity by shells may be useful as an index to measure the condition index of oysters. 2. As a whole, monthly changes of moisture and fat content in oysters were reversely correlated. Protein content slightly decreased from April and rapidly decreased in July, and again rapidly increased in August but from September to November decreased slightly. In April, the content of glycogen was 4 percent. From this period to September, glycogen was rapidly decreased. From July to September, it was only 0. 7 to 1 percent but increased from October. There were little seasonal changes in pH value. The pH value of oyster meat was 6.0 to 6.2. The crude ash content was slightly decreased from June to August. 3. The range of monthly change of heavy metal content are as follows: Total mercury was 0 to 0.019 ppm, cadmium was 0.026 to 0.053 ppm, copper was 0.111 to 0.594 ppm, and lead_was 0.061 to 0.581 ppm. 4. By the results of condition index, chemical composition and heavy metal content of oysters, the suitable harvest season as raw materials for processing was the end of December to the end of May of next year. 5. The pretreatment of 10 percent polyphosphate in 5 percent salt solution of oyster meat appeared effective to reduce thawing drip during cold storage. 6. The pretreatment of $Na_2EDTA$ and BHA did not show the color prevention effect to the canned oyster meat during storage. 7. Magnesium chloride affected to open the valves of oysters.