말똥성게 (Hemicentrotus pulcherrimus)의 생식세포 및 pluteus 유생을 이용하여 중금속인 Arsenic (As)와 Chromium (Cr)이 정상 수정률 및 배아 발생률에 미치는 독성 영향을 조사하였다. H. pulcherrimus의 수정률 및 배아 발생률에 미치는 As와 Cr의 독성은 6.25, 12.5, 25, 50, 100 ppb의 농도에서 조사하였다. 0.5 M KCl 용액을 이용하여 방란 및 방정을 유도하였고, 정상 수정률 및 배아발생률은 수정 후 각각 10분 및 64시간째 관찰하였다. As와 Cr을 첨가하지 않은 대조구에서 정상 수정률과 배아 발생률은 각각 94%와 93% 이상을 나타냈다. 이들 중금속 첨가에 의해 수정률은 아무런 변화가 나타나지 않았지만 배아 발생률은 농도 의존적 감소하는 것으로 나타났으며, As의 첨가에 의해 배아 발생률은 6.25 ppb에서 유의적으로 감소하였으며 (P⁄0.01), Cr의 경우는 25 ppb에서 유의적인 감소를 나타냈다 (P⁄0.05). H. pulcherrimus의 정상 배아 발생률에 대한 LOEC는 As의 경우는 6.25 ppb를 Cr은 25 ppb를 나타냈다. 이들 연구결과로 해양생태계 내에서 As가 6.25 ppb, Cr이 25 ppb를 초과하는 농도일 때는 H. pulcherrimus와 같은 무척추동물의 정상부화율은 급격히 감소할 것으로 판단된다. 본 연구결과를 바탕으로, H. pulcherrimus의 정상 배아 발생률을 이용한 생물학적 평가방법은 중금속과 같은 유해물질에 대한 해양생태계의 영향을 판단하기 위한 시험방법으로 유용하게 이용될 수 있을 것으로 판단된다.

The present study was carried out to assess the dietary exposure and the risk for arsenic (As) and mercury (Hg) through mushrooms intake. Various samples (n = 536) covering 17 kinds of mushrooms were collected from retail outlets and markets in Korea. The contents of As were 0.003 (King oyster) ~ 1.952 (Matsutake) mg/kg in raw mushrooms and 0.015 (Fuscoporia obliqua) ~ 16.95 (Matsutake) mg/kg in dry mushrooms, respectively. The contents of Hg were 0.001 (King oyster) ~ 0.030 (Matsutake) mg/kg in raw mushrooms and 0.004 (Oyster) ~ 0.588 (Matsutake) mg/kg in dry mushrooms, respectively. The mean dietary exposures of As was 0.151 μg/day, taking 0.005% of provisional tolerable weekly intake (PTWI). The mean dietary exposures of Hg was 0.022 μg/day, corresponding to 0.071% of PTWI. Therefore, the level of overall dietary exposure to As and Hg for Korean population through mushroom was far below the levels recommended by Joint FAO/WHO Expert Committee on Food Additivies, indicating little possibility of concern.

본 연구에서는 폐금속 광산 주변 비소와 중금속으로 오염된 논토양을 효과적으로 복원하기 위한 안정화 제로써 석회석과 제강슬래그의 처리효과와 그 적용성을 검토하기 위해 담수답의 환원 환경을 적용한 컬럼 실험을 실시하였다. 실험결과 담수된 논토양의 환원 환경에서는 철과 망간 성분이 환원되어 급격하게 용출되는 시점에 중금속 성분도 급격하게 용출되는 경향이 나타났으며, 대조구(무처리)의 경우 침출수에서 오염기준을 초과한 시료가 나타났다. 그러나 석회석 5%와 제강슬래그 5%로 각각 처리한 토양은 모두 오염기준 이하로 대조구보다 중금속 농도가 매우 낮게 검출되었다. 석회석과 제강슬래그 모두 담수답의 환원 환경에서 좋은 처리효과를 나타내어 효과적인 안정화제로 판단되었으며, 특히 제강슬래그는 담수답 환 경에서 지속적으로 증가하는 비소 성분에 대해서 좋은 처리효과를 나타내었다.

Hybridization of semiconductor materials with carbon nanotubes (CNTs) is a recent field of interest in which new nanodevice fabrication and applications are expected. In this work, nanowire type GaAs structures are synthesized on porous single-wall carbon nanotubes (SWCNTs) as templates using the molecular beam epitaxy (MBE) technique. The field emission properties of the as-synthesized products were investigated to suggest their potential applications as cold electron sources, as well. The SWCNT template was synthesized by the arc-discharge method. SWCNT samples were heat-treated at 400˚C under an N2/O2 atmosphere to remove amorphous carbon. After heat treatment, GaAs was grown on the SWCNT template. The growth conditions of the GaAs in the MBE system were set by changing the growth temperatures from 400˚C to 600˚C. The morphology of the GaAs synthesized on the SWCNTs strongly depends on the substrate temperature. Namely, nano-crystalline beads of GaAs are formed on the CNTs under 500˚C, while nanowire structures begin to form on the beads above 600˚C. The crystal qualities of GaAs and SWCNT were examined by X-ray diffraction and Raman spectra. The field emission properties of the synthesized GaAs nanowires were also investigated and a low turn-on field of 2.0 V/μm was achieved. But, the turn-on field was increased in the second and third measurements. It is thought that arsenic atoms were evaporated during the measurement of the field emission.

Although concerns about Arsenic (As) contamination in agricultural foods have currently increased, there in on adequate international risk management standards for As particularly on agricultural commodities and processed agricultural products. This scenario holds true also in Korea. Australia, and New Zealand has determined the As maximum level (ML) but only on cereals grains which is based on total As contents. In addition,Japan has regulated the ML based on trivalent As contents in agricultural commodities, which do not have legal restrictions. On the other hand, China has developed a systemic risk management to restrict the As contamination above MLs in agricultural commodities and processed agricultural products based on inorganic and total As contents. The establishment of an adequate analytical method for As specification in agricultural foods is essential to determine the acceptable level of As in agricultural food. Probabilistic approach may remove some uncertainties in calculating human risk assessment from As. It should be reviewed in terms of maximum levels to set the best scenario based on a realiability and availability to achieve effective As management on agricultural foods in Korea.

This study was concentrated that the contents of heavy metals were estimated from 782 samples of sold fisheries in Seoul(33 species in fishes, 15 in bivalves, 12 in crustaceans and 10 in others) by Atomic Absorption Spectrometer. The contents of As, Cd and Pb [minimum-maximum (mean)] were N.D.-0.162 mg/kg(0.021), 0.001-0.120 mg/kg(0.014) and 0.015-0.499 mg/kg(0.111) in fishes, 0.003-0.311 mg/kg(0.052), N.D.-1.905 mg/kg(0.182) and 0.013-0.462 mg/kg(0.138) in bivalves, N.D.-0.328 mg/kg(0.042), 0.002-1.113 mg/kg(0.079) and 0.006-0.510 mg/kg(0.109) in crustaceans, N.D.-0.181 mg/kg(0.024), 0.001-0.214 mg/kg(0.033) and 0.010-V0.877 mg/kg(0.118) in others respectively, bivalves were the highest than others. The average weekly intakes of three metals from sold fisheries took about 1.4-26.4% of PTWI (provisional tolerable weekly intakes) that FAO/WHO Joint Food Additive and Contaminants Committee had set to evaluate their safety.

생쥐에서 카드뮴이나 비소의 전처리에 의하여 카드뮴과 비소의 치사독성이 완화되는 효과가 카드뮴과 비소를 교차 전처리 한 경우에도 이 같은 효과가 나타나는지를 조사하였다 치사량의 비소를 주사하기 전에 치사량 이하의 비소를 생쥐에 주사하면 치사량의 비소에 의한 치사작용이 완화되는 효과가 나타나며 카드뮴 전처리에 의해서도 카드뮴의 치사독성은 완화되었다. 두 경우에서 생존한 개체의 간조직의 glutathione함량은 대조군과 별 차이가 없었으나 치사한 개체는 그

In Korea, a small proportion of fishery products are contaminated with a considerable amount of potentially hazardous contaminants. So, there is generally a high risks to consumers. Inorganic contaminants with the greatest potential for toxicity are Sb, As, Cd, Pb, Hg, Se and the Sulfides. As appears to be much more variable than the others. This study was performed to assess the levels of the As in fisheries caught from the waters of the western coast of Korea. The samples included 26 kinds of fishes, 18 kinds of Mollusca, 3 kinds of Crustacea and 7 kinds of salted fishes. The Moisture content of molluscans was significantly higher than that of others (p$lt;0.05). And the As contents of crustaceans were significantly higher than those of fishes, molluscans and salted fishes (p$lt;0.05). The As content of Turban shell was 51.62 ppm, which was the highest among the samples. Also, the As contents of eel, cattle fish and blue crab were found to be higher than in other fisheries. This variability offers a solution for the reduction of eosure to As through restricting the harvest of aquatic organism from the western coast of Korea.

본 연구는 원자력 시설 해체 시 발생되는 저준위 및 극저준위 폐토양, 점토와 산업부산물인 고로슬 래그를 이용하여 방사성 폐기물을 안전하게 담지할 수 있는 비소성 시멘트의 제조 가능성을 평가하고 광물· 형태학적 분석을 통하여 생성된 반응 물질에 대하여 고찰하였다. 본 연구에서는 (1) 폐토양, 점토 및 고로슬 래그의 특성 분석, (2) 폐토양, 점토 및 고로슬래그를 고화재 및 성분조정제로 이용한 원전 해체 폐기물 담지를 위 한 비소성 시멘트 제조 및 최적의 배합 비율 도출, (3) 제조된 비소성 시멘트 고화체의 수화반응 생성물질에 대하여 광물·형태학적 분석 등을 수행하였다. 비소성 시멘트 고화체의 광물·형태학적 분석 결과, 폐토양과 점 토는 수화반응 생성물이 관측되지 않았으며, 고로슬래그의 경우 고화체의 강도를 발현시킬 수 있는 수화반응 생성물질인 calcium silicate hydrate (CSH), 에트링가이트(ettringite)가 생성되는 것을 확인하였다. 폐토양, 점 토를 고화재로 이용한 비소성 시멘트의 재령 28일 후 고화체는 최적의 배합 비율에서 약 3 MPa의 강도를 나 타내 처분장 인수기준 압축강도인 3.44MPa를 만족하지 못하는 것을 확인하였다. 그러나, 고로슬래그를 고화 재로 이용한 비소성 시멘트는 모든 실험 조건에서 처분장 인수기준 압축강도를 만족하며, 최적의 배합 비율 에서는 약 27 MPa로 높게 나타나는 것을 확인할 수 있었다. 이러한 결과를 통하여 비소성 시멘트 고화재로 고로 슬래그, 방사성 핵종에 대한 흡착제 역할로 폐토양 및 점토를 이용한다면 방사성 폐기물 처분을 위한 최적의 비소성 시멘트를 제조할 수 있을 것으로 판단된다.

In this study, we evaluated the effect of the type of sewage sludge (digested, non digested) on drying efficiency according to the polymer injection rate. The drying characteristics were shown using a near-infrared ray (NIR) and a microwave. As a result of the drying characteristics with NIR at a polymer dose ratio of 8%, the heating up period is up to 6 minutes after the start of the drying experiment. Afterwards, the constant rate drying period of the digested sludge (A, C and G sites) was 6 minute → 18 minute, showing a rapid decrease in moisture. On the other hand, non digested sludge (B, D, E, F, H, I, J and K sites) showed gradual drying characteristics compared to digested sludge until complete drying (10%). As the polymer dose ratio of 10% and 12%, the heating up period for digested sludge is up to 6 minute after the start of the experiment. Afterwards, the constant rate drying period of the digested sludge was 6 minute → 20 minute, showing a rapid decrease in moisture. On the other hand, the heating up period of non digested sludge was up to 10 minute after the start of the experiment, and the constant rate drying period was 10 minute → 22 minute, which was shorter than digested sludge. As a result of the drying characteristics with microwave at a polymer dose ratio of 8%, 10% and 12%, the constant rate drying period the digested sludge was 4 minute → 20~22 minute, showing a rapid decrease in moisture. On the other hand, non digested sludge of the constant rate drying period was 4 minute → 22~30 minute, which was longer than digested sludge.

Arsenic is among the heavy metals commonly found in aqueous environments. Iron oxide is known as an efficient adsorbent for the arsenic. A new synthetic method was applied to provide iron oxide giving a large specific surface area. The mixing method affects the formation of iron oxide. Ultrasonic waves assisted the formation of very fine iron oxide in an organic phase. The synthesized iron oxide is amorphous type with a high surface area of more than 181.3 m2/g. Sorption capacity of the synthesized adsorbent was relatively very high for arsenic and varied depending on the oxidation state of arsenic: a higher capacity was obtained with As(V). Lower solution pH provided a higher sorption capacity for As(V). The competitive effect of co-exist anions such as chloride, nitrate, and sulfate was minimal in sorption capacity of the iron oxide for arsenic.

최근 화력발전소에서는 순환유동층 연소방식의 발전소가 증가하는 추세이다. 순환유동층 보일러애시는 탈황 효과를 위해 석회석을 첨가함에 따라 애시 중에 포함되는 CaO, SO3성분이 증가하여 일반적인 플라이애시 보다 free-CaO 함량이 높다. 또한 순환유동층 보일러애시는 기존의 플라이애시와 다르게 자기수경성 특성과, 높은 free-CaO함량에 의해 물과 만나면 높은 반응성을 갖는다. 본 연구는 순환유동층 보일러애시의 자기수경성 특성을 이용하여, 시멘트를 대체할 수 있는 비소성 결합재로써 활용 가능성에 대해 분석하였다. 순환유동층 보일러 애시의 함량에 따른 역학적 및 수화특성에 대해 검토하였다. 또한 석고의 종류 및 함유량에 따른 순환유동층 보일러애시 활용 비소성 결합재에 대 한 압축강도 및 미세구조에 미치는 영향을 분석하였다.

This study was performed an evaluation of compressive strength of NSB mortar according to BP contents and curing conditions. As the results of study, compressive strength increase as BP content and curing temperature was increased. When considering the strength properties of BP NSB mortar, the proper BP content and curing temperature are thought to be 20% and 60℃ respectively.

The removal characteristics of As and Se ions from aqueous solution by hexadecyl trimethyl ammonium bromide (HTMAB) modified anthracite (HTMAB-AT) were investigated under various conditions of contact time, pH and temperature. When the pH is 6, the zeta potential value of anthracite (AT) is 24 mV and on the other hand, the zeta potential value of the HTMAB-AT is +44 mV. It can be seen that the overall increase of about 60 mV. Increasing the (+) potential value indicates that the surface of the adsorbent had a stronger positive charge, so adsorption for the anion metal was increased. The isotherm data was well described by Langmuir and Temkin isotherm model. The maximum adsorption capacity was found to be 7.81 and 6.89 mg/g for As and Se ions from the Langmuir isotherm model at 298 K, respectively. The kinetic data was tested using pseudo first and pseudo second order models. The results indicated that adsorption fitted well with the pseudo second order kinetic model. The mechanism of the adsorption process showed that adsorption was dependent on intra particle diffusion model according to two step diffusion. The thermodynamic parameters(ΔGo, ΔHo, and ΔSo) were also determined using the equilibrium constant value obtained at different temperatures. The thermodynamic parameters indicated that the adsorption process was physisorption, and also an endothermic and spontaneous process.