• Food Science and Biotechnology
• /
• 제17권3호
• /
• pp.447-456
• /
• 2008

Limonene, pinene, and isoprene are abundant and ubiquitous volatile organic compounds (VOCs) which are found in various natural products and also produced from various manufacture processes. Limonene and pinene are major components of food additives and household products for enrichment of good flavors and elimination of malodors, and isoprene is a basal motif of monoterpenes such as limonene and pinene. They have shown many beneficial effects such as chemopreventive, chemotherapeutic, and antioxidant activities. Upon certain conditions, however, adverse effects of these compounds on human health have also been reported. Although they do not seem to have acute and severe toxicity to human, they can easily generate secondary organic aerosols (SOAs) when they react with oxygen and/or ozone, which have shown certain toxic effects on experimental animal models as well as on humans. Numerous household and scented products containing limonene, pinene, and isoprene are widely used in these days. However, biological consequences upon exposure to these products are largely unknown. The aim of this review is to summarize and analyze the current understanding on the biological effects of VOCs, in particular limonene, pinene, and isoprene, as well as their SOAs.

• 한국수산과학회지
• /
• 제47권6호
• /
• pp.1014-1025
• /
• 2014

We measured the concentrations of various geochemical parameters [grain size, ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS), and trace metals (Fe, Cu, Cd, Pb, Cr, Mn, As, Zn, and Hg)] in the surface sediments of two intertidal oyster Crassostrea gigas farming areas (Iwon and Mongsan tidal flats) on the Taean Peninsula, Korea, to evaluate the pollution level of organic matter and trace metals in sediment. The intertidal sediments in the study region comprise mostly sand with a mean grain size of 2.5-3.5 Ø. The concentrations of IL, COD, AVS, and trace metals in the sediment of two study regions were either similar or lower in oyster farming areas relative to non-farming areas, apparently due to biological uptake or physical and biological sediment reworking. Based on the results for the pollution evaluation of organic matter and trace metals derived from sediment quality guidelines, enrichment factor, and geoaccumulation index, our results suggest that the sediment in these two intertidal oyster farming regions is not polluted by organic matter and trace metals.

• Macromolecular Research
• /
• 제14권3호
• /
• pp.272-286
• /
• 2006

Dendritic hyperbranched poly(methyl methacrylate)s (PMMA)s, whose branched architectures resemble the 'dendron' part(s) of dendrimer, were synthesized by an iterative methodology consisting of two reactions in each iteration process: (a) a coupling reaction of u-functionalized, living, anionic PMMA having two tert-butyldimethylsilyloxymethylphenyl(SMP) groups with benzyl bromide(BnBr)-chain-end-functionalized PMMA, and (b) a transformation reaction of the introduced SMP groups into BnBr functionalities. These two reactions, (a) and (b), were repeated three times to afford a series of dendron-like, hyperbranched (PMMA)s up to third generation. Three dendron-like, hyperbranched (PMMA)s different in branched architecture were also synthesized by the same iterative methodology using a low molecular weight, functionalized 1,1-diphenylalkyl anion prepared from sec-BuLi and 1,1-bis(3-tert-butyldime-thylsilyloxymethylphenyl)ethylene in the reaction step (b) in each iterative process. Furthermore, structurally similar, dendron-like, hyperbranched block copolymers could be successfully synthesized by the iterative methodology using $\alpha$-functionalized, living, anionic poly(2-(perfluorobutyl) ethyl methacrylate) (PRfMA) in addition to $\alpha$-functionalized, living PMMA. Accordingly, the resulting block copolymers were comprised of both PMMA and PRfMA segments with different sequential orders. After the block copolymers were cast into films and annealed, their surface structures were characterized by angle-dependent XPS and contact angle measurements. All three samples showed significant segregation and enrichment of PRfMA segments at the surfaces.

• 한국해양학회지:바다
• /
• 제16권4호
• /
• pp.169-179
• /
• 2011

본 연구에서는 미량 금속의 농축 가능성이 제기되는 천수만 퇴적물에 대하여 미량 금속의 조절 요인과 농축 정도를 파악하고자 하였다. 천수만 전역에 걸쳐 27개의 표층 퇴적물을 채취하였으며, 입도, 비표면적, 유기탄소 및 탄산칼슘 함량과 주성분 및 미량 금속(Al, Fe, Na, K, Mg, Ca, Ti, Mn, P, S, Ba, Sr, Li, Co, Cr, Ni, Cu, Zn, As, Cd, Cs, Sc, V, Sn) 농도를 분석하였다. 퇴적물의 총 금속 농도는 크게 3 가지 요인(석영, 희석, 탄산칼슘, 굵은 모래 혹은 정장석)에 의해 조절되었는데 V, Co, Cr, Ni, Cu, Zn, As, Cd는 석영 희석 효과(quartz dilution effect)에 의해 Mn 및 As는 석영 희석 효과와 정장석(굵은 모래) 함량의 복합적 요인에 의해 조절되었다. 농축 인자(enrichment factor) 및 약산(1 M HCl) 용출 실험 결과 천수만 퇴적물에서 미량 금속은 농축되지 않았음을 알 수 있었으며 금속의 농도는 퇴적물의 지화학적 특성들로 잘 설명되었다. 특징적으로 As는 조립질 퇴적물에서도 세립질 퇴적물과 유사한 농도를 보여주었는데, 이것은 조립질 퇴적물 내 Mn 산화물(용출 부분) 및 정장석(잔류 부분)과 밀접한 관련이 있는 것으로 해석되었다. 따라서 퇴적물 중 As의 농축 정도를 평가할 경우, 모래질을 포함하는 시료는 모래질 부분을 따로 분리하거나 $16{\mu}m$보다 작은 세립질 퇴적물의 함량이 10% 이상인 시료만을 대상으로 하는 것이 합리적인 것으로 판단된다.

• 한국산학기술학회논문지
• /
• 제17권12호
• /
• pp.333-338
• /
• 2016

시화호 표층퇴적물 중 지구화학적 특성과 미량금속의 오염도 평가를 위해 입도, 강열감량(IL), 화학적산소요구량(COD) 및 미량금속(As, Pb, Cd, Cu, Cr, Zn, Ni, Mn, Hg, Fe, Li)을 분석 하였다. 시화호 표층퇴적물의 평균입도는 2.94~6.35Ø의 범위로 분포하였으며, 퇴적상은 전반적으로 sandy silt(sZ)를 나타내었고, 이러한 표층퇴적물의 성상은 유기물 및 미량금속의 농도와 상관관계를 나타내었다 (p<0.05). 특히, 표층퇴적물 중 As, Pb, Cd, Cu, Cr, Zn, Fe, Hg은 평균입도와 상관성을 보일 뿐만 아니라, IL(Ignition Loss)과도 높은 상관성을 보여 이들 원소의 농도가 입도와 유기물의 영향을 받고 있는 것으로 나타났다. 이에 시화호의 표층퇴적물 관리에 있어서 미량금속의 유입 뿐 만 아니라 유기물의 유입을 병행하여 조사되어야 할 것으로 판단되었다. 오염도 평가에 있어서 표층퇴적물 중 미량금속 함량의 농축계수와 농집지수는 대부분 약간 오염된 상태를 나타낸 가운데, As의 경우 농축계수와 농집지수 가 오염된 상태를 보였다. 이는 특정 중금속에 의한 농축이 여전히 해결되지 않은 것으로 나타나, 이를 해결할 수 있는 방안마련이 시급할 것으로 사료되었다. 아울러 비교적 공단지역 및 배수갑문에 근접한 지역은 오염도가 높은 반면, 시화호 중앙부분은 오염도가 낮은 경향을 보여, 지역적 편차를 고려한 지속적인 모니터링시 이 필요할 것으로 판단되었다.

• 한국수산과학회지
• /
• 제48권4호
• /
• pp.542-554
• /
• 2015

Grain size, the content of ignition loss (IL), and the concentrations of chemical oxygen demand (COD), acid volatile sulfide (AVS), and trace metals (Fe, Mn, Cu, Pb, Zn, Cd, Cr, As, and Hg) in surface sediments from the Taehwa River estuary, Ulsan, were measured to evaluate pollution levels and potential ecological risks of organic matter and trace metals in estuarine sediment. The mean grain size (Mz) of sediments in the study region ranged from $-0.8-7.7{\varphi}$ (mean $2.8{\pm}2.4{\varphi}$). Surface sediments in the upstream region of the Taehwa River were mainly composed of coarse sediments compared to the downstream region. The concentrations of IL, COD, AVS and trace metals in the sediment were much higher at downstream sites of Myeongchon Bridge in the vicinity of industrial complexes than at upstream sites of those in the vicinity of the residential areas due to the anthropogenic input of organic matter and trace metals by industrial activities. On the basis of several geochemical assessment techniques [sediment quality guidelines (SQGs), enrichment factor (EF), geoaccumulation index ($I_{geo}$), pollution load index (PLI) and ecological risk index (ERI)], the surfaces sediments in the study region are not highly polluted for trace metals, except for As. However, the higher concentrations in downstream study regions of the Taehwa River could impact benthic organisms including shellfish (i.e. Manila clam) in sediments.

• Ocean and Polar Research
• /
• 제25권1호
• /
• pp.41-52
• /
• 2003

Sediment trap samples were collected to find out characteristic behaviors of metals in the settling particles by using time-series sediment traps at 678m and 1678m water depths in the Bransfield Strait from December 27th, 1999 to December 26th, 2000. Total mass fluxes at the intermediate water depth (678m water depth) were high in the austral summer and low in the austral winter, whereas at the deep water depth (1678m water depth) they showed high values in both the summer and winter. Total mass fluxes were generally higher in the deep water depth than in the intermediate water depth, which indicates that a substantial amount of sediments are laterally transported by strong currents into the deep basin from the shallow water depths. Aluminium contents also showed large seasonal variations with high values in the winter and low values in the summer. On the contrary, organic carbon contents were high in the summer and low in the winter. Al contents were negatively correlated with organic carbon contents, which may be ascribed that detrital particles are diluted by organic matter produced by phytoplankton in the surface waters. Metals measured in this study exhibited three characteristic behaviors; 1) a positive correlation with Al-Ti, Fe, Mn, V, Co, and Ba, 2) a negative correlation with Al-Cd and Zn, 3) no relationship with Al-Sr, Cu, Cr, Ni. Terrestrial materials may act as a major source fer metals that are positively correlated with Al, and organic matter may be a major source for metals that are negatively correlated with Al. Enrichment factor (EF) of Fe, Mn, Ba, Vi Co, Sr, Cr, and Ni ranged from 0.5 to 1.5, whereas EF of Zn, Cu, and Cd showed much higher values than 1.

• 한국수산과학회지
• /
• 제46권4호
• /
• pp.454-466
• /
• 2013

To evaluate the organic matter and trace metal pollution in intertidal sediment of the coastal zone, various geochemical parameters (grain size, ignition loss [IL], chemical oxygen demand [COD], acid volatile sulfide [AVS], and metals [Al, Fe, Cu, Pb, Zn, Cd, Cr, Mn, Hg, and As]) were measured for the intertidal surface sediment of the mainland and islands between Mokpo and Haenam in the southwestern coast of Korea. The surface sediments consist mainly of finer sediments, such as mud and silt. The concentrations of IL, COD, and trace metals in intertidal sediment were relatively high in the shoreline of the mainland than in that of islands and those in some stations exceeded the sediment quality guidelines (SQGs). Moreover, the concentrations of IL, COD, and trace metals (except As) in sediment showed relatively good positive correlations with mean grain size, indicating that the concentrations of organic matter and trace metals in intertidal sediment of the study region are dependent on grain size of sediment. Pollution evaluation for trace metals using geochemical assessment techniques, such as enrichment factor, geoaccumulation index, and SQGs, suggested that the intertidal sediments in the study region show light pollution with Cr and moderate pollution with As. More extensive interdisciplinary studies are required to determine the potential causes of As pollution in intertidal sediment.

• 한국환경과학회지
• /
• 제11권3호
• /
• pp.215-225
• /
• 2002

In order to evaluate the relationship between geochemical characteristics and benthic facies of the sediments from the Oenaro Island where red tide proliferation is first observed every year including this year, surface and short multiple core sediment samples were analyzed in terms of geochemical and benthic facies variation. The contents of organic carbon, carbonate, and sulfide gas were relatively low. The variation in C/N ratios, which indicate nature of organic carbon, suggested that the organic carbon recorded in the study area is composed of mixtures of marine and terrigenous organic matters. The concentration of minor elements found at the surface and multiple core sediment samples were also low as well as the enrichment factors(Ef) for the seven heavy metals indicated that the sediment of this area is not polluted significantly. The macrobenthic faunal community comprised 61 species, and their mean density was 708 ind./m2. Polychaete worms were major taxa of this benthic community. A crustacean amphipod, Melita sp. was the most abundant species accounted for 20.7% of total abundance, and the small polychaetes such as Heteromastus filiformis, Paralacydonia poradoxa, Magelona japonica and Sigambra tentaculata were the next dominant species. The macrobenthos around the Oenaro Island were more diverse and abundant than that in Gamak Bay. The benthic communities in the study area sustained somewhat different species composition based on the cluster analysis and the MDS ordination. The benthic community health condition at three stations seemed to be unbalanced, and slightly polluted based on the biological index such as BPI and BC. There was no clear relationship between the geochemistry characteristic and the benthic faunal facies attributed by the micro-algal blooms in this coastal area.

• 자원환경지질
• /
• 제19권spc호
• /
• pp.163-173
• /
• 1986

Black and graphite slates from the Okcheon metamorphic belt contain enriched values of uranium (average 200~250ppm) and molybdenum (average 150~200ppm). Uranium mineralization is closely associated with quartz and sulfide veinlets which are formed diagenetically in graphite slate. The uranium minerals were concentrated in outer part of graphite nodules. The ${\delta}^{13}C$ values of organic carbon from the metasediments including uranium bearing graphite slate range from -15.2 to -26.1‰ with a mean of -23.5‰. Meanwhile, ${\delta}^{13}C$ values of coal and coaly shale from some Paleozoic coal fields of South Korea vary from -19.4 to -23.9‰ with an average of -22.5‰. Isotopic compositions of vein calcite in uranium bearing slate range from -13.4 to -15.4‰ in ${\delta}^{13}C$ and +11.3 to +15.1‰ in ${\delta}^{18}O$ could indicate a reduced organic carbon source isotopically exchanged with a graphite of biogenic origin. Metamorphic temperature determined by a calcite-graphite isotope geothermometer was 383~$433^{\circ}C$ which corresponded to greenschist facies by Miyashiro (1973) and is consistent with metamorphic facies estimated by mineral assemblages (Lee, et al., 1981, and Kim, 1971). The fixation of uranyl species by carbonaceous matter in marine epicontinental environment, and remobilization of organouranium by diagenetic processes have attributed to the enrichment of uranium and heavy metals in the graphite slate of Okcheon metamorphic belt.