• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.550-558
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• 2021

In a radiotracer study, the bioaccumulation and efflux of metals in earthworms (Eisenia fetida) exposed to soil spiked with ZnO and Ag nanoparticles (AgNP) were compared to those exposed to soil spiked with ionic Zn and Ag. Additionally, the bioavailability and chemical mobility of nano- and ionic metals in the soil were estimated using the sequential extraction method and compared to the bioaccumulation factor(BAF). The BAF for ZnO (0.06) was 31 times lower than that for Zn ions (1.86), suggesting that ZnO was less bioavailable than the ionic form in contaminated soil. In contrast, the BAFs for two types of AgNPs coated with polyvinylpyrrolidone (0.12) or citrate (0.11) were comparable to those of ionic Ag (0.17). The sequential extraction of metals from the soil suggests that the chemically mobile fractions in the Zn ion treatment were higher(35%) than those (<20%) in the Ag ion treatment, which was consistent with the greater BAFs in the former than the latter. However, the chemical mobility in the ZnO treatments did not predict bioavailability. The efflux rates of Ag (3.2-3.8% d^-1) in the worms were 2-3×those(1.2-1.7% d^-1) for Zn.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.3
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• pp.60-70
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• 2012

Zn, Cu, Fe, Al contents of sludges produced from sewage treatment plants and night soil treatment plant in Pocheon City, Gyeong-gi Province were investigated. And the accumulated contents of those metals in the earthworm Eisenia fetida were also investigated while 15, 30, 45, 60, 75, 90, 105 grams(dw) of sludges were cumulatively supplied to the earthworms. Zn contents of sludges were 75.1~196.1 mg/kg, Cu contents 3.74~76.1 mg/kg, Fe contents 219.9~857.8 mg/kg, Al contents 198.4~991.7 mg/kg, all of which would not cause acute toxicity to the earthworm, but could cause sublethal effects on earthworm and reduce the density of next generation's population. However, cumulative supplies of sludges didn't increase the bioaccumulation rates of metals in the earthworm body, and BAFs of those metals after 60g of sludge supply were 0.0~0.43, which meant that the accumulated Zn, Cu, Fe, Al contents in the earthworm were lower than those of sludges.

• Korean Journal of Poultry Science
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• v.14 no.1
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• pp.15-24
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• 1987

A total of 216 day-old broiler chickens were randomly assigned to 6 treatment combined 2 dietary protein regimens (22-20%, 20-18% for starter and finisher, respectively) with 3 times of change (2, 4, 6 weeks) to study the effects of different protein levels and time of change from starter to finisher ration on the performance of broilers. Increasing the dietary protein level resulted in not only a significant increase in the body weight gain and the protein requirement per kg body weight gain, but also an improvement of feed efficiency. However abdominal fat accumulation was decreased by adding incremental levels of protein. On the other hand, the earlier time of change from starter to finisher ration, less\ulcorner\ulcornerbody weight gain and the abdominal fat accumulation. But feed intake and viability were not affected by the dietary protein level and/or the time of change from starter to finisher ration. Income was highest for birds fed 22% and 20% protein diet' starter and finisher, respectively changed from starter to finisher at 4weeks of age.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.457-460
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• 2000

A biofilm airlift reactor filled with biomass-covered carriers (sand) were used to remove ammonium by selective nitrification (ammonium to nitrite). The effects of experimental conditions (ammonium load, pH, dissolved oxygen) on nitrification and nitrite accumulation were investigated. The reactor showed more than 90% nitrification efficiencies at 2.5 kg $NH_4\;^+-N/m^3/d$ and $NO_2\;^--N$ could be accumulated between 75% and 90% in the effluent. It is likely that nitratation (nitrite oxidizer) was inhibited by low dissolved oxygen concentration while nitritation (ammonium oxidizer) was kept stable.

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.2
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• pp.136-146
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• 2007

Landfill leachate was successfully treated in upflow anaerobic sludge blanket (UASB) reactors regardless of the addition of granular sludge. Initial operating period was significantly reduced by the addition of granular sludge. At hydraulic retention time (HRT) of one day, chemical oxygen demand (COD) removal rates in Control and Granule reactor were maintained over 90%, respectively with organic loading rate (OLR) of $4-8kgCOD/m^3.d$. During the experiment, the inorganic precipitates were accumulated in and around the sludge, and in the wall of the reactors were formed in both reactors regardless of addition of granular sludge. Specific methanogenic activity (SMA) increased as adaptation of microorganism to the substrate and OLR were increased. The maximum SMA value of the sludge for Granule reactor was about $0.57gCOD/g{\cdot}VSS{\cdot}.d$. The SMA value was not decreased because of excessive inorganic accumulation, however, it was needed to have pre-treatment process of influent to remove the inorganic metals.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.339-339
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• 2020

도시화로 인한 불투수면적의 증가와 기후 변화로 인한 강우패턴의 변화 자연적 물순환 체계에 악영향을 미치며. 이를 해결하기 위하여 국내에서는 도시 내 빗물관리 및 비점오염원 저감이 가능한 저영향개발(Low Impact Development, LID)를 적용하고 있다. 건기시 도로, 주차장등 차량통행 및 유동인구가 많은 지역에서는 입자상 물질들이 많이 발생되어 노면에 축적되어 있다가 강우시 강우유출수를 통해 시설로 유입된다. 이로 인해 시설 내 오염물질 및 퇴적물이 축적되어 여재 공극막힘현상 및 침투율저하의 문제가 발생되어 시설 내 효율이 감소된다. 따라서, 레인가든의 장기 모니터링을 통해 시설 내 유입되는 오염물질의 성상 분석 및 시설 내부의 퇴적물 분석을 통해 LID시설 운영의 효율성 평가를 수행하였다. 모니터링은 강우시 모니터링과 건기시 집수구역, 침강지, 시설 상부, 중부, 하부 등 총 5곳에서 채취하여 분석을 수행하였다. 모니터링은 평균 선행건기 일수는 5.46±4.7 days, 평균 강우량은 14.31±11.4 mm, 평균 강우강도는 5.33±6.7 mm/hr의 강우사상에서 모니터링을 수행하였다. 시설 내 평균 유입수농도는 TSS 98.0 ± 32.7 mg / L, COD 133.6 ± 6.3 mg / L, TN 5.77 ± 4.05 mg, TP 0.54 ± 0.03 mg / L으로 분석되었다. 유입부 내 퇴적물 종류는 Sandy Clay Loam으로 나타났으며, Cr 0.36mg / kg, Cu 5.17 mg / kg and Pb 6.04 mg / kg으로 중금속의 함유량이 높은것으로 분석되었다. 퇴적물은 침강지 및 시설 유입부에서의 입자크기는 49-113㎛ 약 60%의 퇴적물이 축적되어 제거되는 것으로 나타났다. 시설 내 침강지에서 50㎛ 이상의 입자들이 여과, 흡착 및 침전으로 인하여 40% 이상의 입자들이 제거되는 것으로 분석되었으며, 50㎛ 미만의 입자들은 시설 내 중간부, 유출부에서 제거되는 것으로 분석되었다. 침강지에서 유입수 대부분의 입자상물질들이 흡착 및 여과로 인한 제거가 이루어지기에 침강지 여재부는 넓은 표면적, 우수한 흡착능 및 여과율을 고려하여 선정하영 하며, 잦은 교체를 위하여 중량성이 낮은 우드칩 등이 적당한 것으로 사료된다.

• Applied Biological Chemistry
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• v.39 no.4
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• pp.287-292
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• 1996

The present study was carried out to investigate the difference of absorption and translocation of Ni by radish grown for 45 days under factors such as the levels of Ni in soil, soil pH, competitive metal interactions, covering with soil, organic matter and lime. Germination rate of radish in soil treated by Ni 150 mg/kg was 40%. As soil pH was increased, the contents of Ni translocated to radish showed the negative correlation$(shoot=-0.965^{**},\;root= -0.837^{*})$. The Ni content in shoot and root of radish grown under 50 mg/kg Ni treated soil were slowly decreased with iron levels increased. However Ni content in shoot and root of radish grown under 50 mg/kg Ni treated soil showed increasing trend with the increasing the zinc levels. As covering with soil, organic matter and lime were treated, Ni contents of shoot and root in radishes were in the decreasing order of organic matter>covering with soil>lime.

• KOREAN POULTRY JOURNAL
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• v.5 no.12 s.50
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• pp.113-118
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• 1973

1. 카나다산 보리의 아미노산조성은 국산보리의 그것과 큰 차이가 없으나 단백질의 함량은 12$\%$로서 국산 보리의 10$\%$보다 약간 높았다. 증체량은 초생추시기에 보리 40$\%$수준이 낮았으나 중추 및 대추시기에는 각 처리구들 사이에 통계적 유의성이 없었으며 2. 사료섭취량과 사료효율은 전시험기간에 걸쳐서 역시 각 처리구 사이에 통계적인 유의성이 없었다. 3. 경제성 분석 결과, 0$\~$6주령에서 보리 40$\%$ 수준이 다소 비싸게 사료비가 소요되었으며 전 육성기간에 걸쳐 5개의 처리에 따른 유의성은 검출되지 않았다. 4. 중추사료의 대사시험 결과 고형물 질소축적률, 조섬유, NFE의 대사율은 각 처리구별로 유사하였으나, 조지방의 소화율은 보리수준이 높아질 수록 소화율도 향상됨을 보여 주었다(P<0.01).

• Horticultural Science & Technology
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• v.29 no.5
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• pp.413-419
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• 2011

This study was conducted to find out the cadmium (Cd) accumulation and tolerance of Iris pseudacorus and Acorus calamus as aquatic plants native to Korea for Cd removal in water. In the range of Cd concentration from $10{\mu}M$ to $130{\mu}M$, the Cd lethal dose 50 ($LD_{50}$) was $78.5{\mu}M$ in I. pseudacorus and $47.6{\mu}M$ in A. calamus. In I. pseudacorus, superoxide dismutase and peroxidase as antioxidants were relatively effective against oxidative stress caused by Cd, while catalase, superoxide dismutase, and polyphenolics were effective in A. calamus. The polyphenolics known as typical antioxidants were not detected in I. pseudacorus. In both species, the Cd accumulation in plants increased with the higher Cd concentration and the longer processing period. Also, the absorbed Cd was accumulated mainly in the roots. The amount of Cd accumulated in the shoot part was maximally $548.1mg{\cdot}kg^{-1}$ (82.1% to Cd accumulated in the root part) in I. pseudacorus and $121.4mg{\cdot}kg^{-1}$ (13.7%) in A. calamus, which implied that both species all were enough evaluated as Cd hyper-accumulators based on 0.01% or more Cd accumulation in the shoot. Especially I. pseudacorus showed outstanding ability to move well Cd into the shoots from the roots and high tolerance to Cd stress.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.2
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• pp.137-145
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• 1990

In this research, biological uptake of heavy metals(Cd(II), Cu(II), Zn(II)) was measured under various conditions ; pH, initial heavy metal concentration, temperature, contact time and the amount of biomass through batch test. From this research, it was found that heavy metals might be removed through adsorption and accumulation in activated sludge process. Heavy metals were highly concentrated by microbial floc in activated sludge. Also, the removal efficiency was reached up to 80~90% within and after 1 hour the increase of removal efficiency was minimal. The order of accumulation efficiency was Cu(II)>Zn(II)>Cd(II), and the bonding strength between heavy metals and microbial floc may be expressed in order of Cu(II)>Zn(II)>Cd(II).