• Journal of the Korean Society for Marine Environment & Energy
• /
• v.9 no.3
• /
• pp.176-186
• /
• 2006

Distribution characteristics of organophosphorous pesticides(OPs) in water and suspended particles were studied in Asan Bay, Korea, from June 2004 to October 2005. 28 organophosphorous pesticides could be detected in Asan Bay during this study. The most commonly and abundantly measured OPs in the surface waters were IBP (max=$6,343.7ng\;l^{-1}$). DDVP, diazionon, ethoprophos and methidathion were also observed at relatively high concentrations. Their maximum concentrations exceeded $100ng\;l^{-1}$ in almost every month. Malathion, mevinphos, ph orate and chlorfenvinphos were also detected at relatively high concentrations. Many OPs more frequently appeared in summer than in winter due to the intensive application of pesticides in summer months. The concentration of OPs generally decreased with increasing distance from the mouth of Asan Bay. This result implies progressive dilution of these pesticides in the marine environment. Measured concentrations of diazinon were well below $20,000ng\;l^{-1}$ which is a limit set by the seawater quality standard of Korea. The concentrations of malathion and parathion in the surface waters of Asan Bay did not exceed the seawater quality standard of Korea($250,000\;and\;60,000ng\;l^{-1}$ respectively). OPs adsorbed on suspended particles were also studied. DDVP, phorate, stirofos, EPN, azinphos-methyl and IBP had higher adsorption capacity onto suspended particles than other pesticides. Calculated pesticide-particle adsorption coefficient($K_d-particle$) for samples collected in Asan Bay were closely related to the reported pesticides-soil adsorption coefficient ($K_d-soil$).

• Korean Journal of Environmental Biology
• /
• v.25 no.3
• /
• pp.273-278
• /
• 2007

The cell numbers of heterotrophic bacteria inhabiting the surface and bottom sea water harvested from the 5 stations in the marine ranching ground of Tongyeong coastal waters in $2003{\sim}2007$ were examined, and species composition of the heterotrophic bacterial population and dominant species were analyzed as well. Sea water samples collected in summer season contained much higher number of heterotrophic bacteria than those harvested in winter, spring and autumn seasons due to the higher sea water temperature. However the cell number of heterotrophic bacteria did not show a significant dependence on the location of the sampling stations. The cell number of heterotrophic bacteria in the surface sea water harvested in October 2003 and in September 2004 was not discernibly different from that in the bottom sea water and sometimes the former was even fewer than the latter because of the typhoon and localized torrential downpour. The number of heterotrophic bacteria decreased every year. The main bacterial species were Pseudomonas fluorescens TY1, Pseudomonas stutzeri TY2, Acinetobacter lwoffii TY3, Sphingomonas paucimobilis TY4, Burkholderia mallei TY5, Pasteurella haemolytica TY6, Pasteurella multocida TY7, Comamonas acidovorans TY8, Actinobacillus ureae TY9 and Chryseobacterium indologenes TY10. P. fluorescens TY1 and A. lwoffii TY3 were found to be the dominant species.

• Journal of Aquaculture
• /
• v.13 no.1
• /
• pp.87-99
• /
• 2000

Field survey on the variational characteristics of water quality and chlorophyll a concentraion were carried out at the 25 stations for four seasons in Kogum-sudo(Straits) southern coast of Korean Peninsula from Feburuary to October in 1993. We made an analysis on biological factor as chlorophyll a concentraion as well as physicio-chemical factors such as water temperature salinity sigma-t transparency dissolved oxygen(DO) chemical oxygen demand(COD) nutrients (ammonia, nitrite, nitrate, phosphate, and silicate) N/P ratio and suspended solid(SS). The waters in the Kogum-sudo were not stratified due to the tidal mixing. And the high productivity in photic layer were supported by high nutrients concentration from bottom waters. The high concen-trations of suspended solid in straits had a bad influence upon marine biology of nature and cultivations. In Kogum-sudo had a sufficient nutrients for primary productivity during a year. Especially phosphate and inorganic nitrogen were high the other side silicate was very low. The source of nutrients supply depend on rather mineralization of organic matters and input of seawater from outside than input of freshwaters from lands. Phytoplankton biomass as measured by chlorphyll a concentratiion was very high all the year round and it was controlled by the combination o f several environmental factors especially of phosphate in summer and dissolved nitrogen in other seasons.

• Journal of the Korean Chemical Society
• /
• v.40 no.2
• /
• pp.109-116
• /
• 1996

A matrix modification was studied for the determination of trace germanium in mineral waters by electrothermal atomic absorption spectrophotometry (ET-AAS). For this, the type and quantity of modifier as well as the use of auxiliary modifier were investigated to realize the efficient modification. Germanium suffers from low sensitivity and poor reproducibility in ET-AAS determination because of the premature loss of germanium via volatile germanium monoxide formation when heated in the presence of carbon. Therefore, the addition of a matrix modifier is necessary to stablize the germanium, thermally and chemically. By the addition of palladium (10 ${\mu}g/mL)$ as a single modifier to the sample containing 500 ng/mL germanium, the charring temperature could be raised from 800 to $1000^{\circ}C$, and its absorbance was also increased, but the atomization temperature was not raised. In this case, the absorbance of germanium was not changed in the range of 10∼70 ${\mu}g/mL$ of palladium added. On the other hand, it was considered that the use of a mixed modifier could modifiy the matrix more effectively than with a single modifier. The best results were obtained by using 1% ammonium hydroxide as an auxiliary modifier together with 10 ${\mu}g/mL$ palladium. The charring temperature could be raised from 800 to $1100^{\circ}C$, without any change of the atomization temperature. With above optimum conditions, the trace amount of germanium in several mineral waters were determined by a calibration curve method, and good recoveries of more than 95% were also obtained in the samples in which a given amount of germanium was spiked. The detection limit of this method was about 6.9 ng/mL.

• The Korean Journal of Malacology
• /
• v.32 no.4
• /
• pp.297-328
• /
• 2016

This study was performed to know and compare the community structures of macrobenthic invertebrates of five fishing grounds in the coastal waters of Jeju Island from 2013 to 2015. A total of 629 species was identified. Molluscans comprised 282 species (44.8%), Arthropods 88 (14.0%), Poriferans 61 (9.7%), Bryozoans 52 (8.3%) and the others including Cnidarians 51 (8.1%). Density and biomass were estimated to be $71,007ind./m^2$ and $599,208.0gwwt/m^2$, respectively. Gastropods was the most dominant taxon in terms of abundance ($24,625ind./m^2$ ) and number of species as well, and Gastropods was predominant in biomass ($190,789.0gwwt/m^2$). The dominant species were Omphalius pfeifferi, Astralium haematragum, Musculus viridulus, Halosydna brevisetosa, Phascolosoma scolops, Herdmania monus in 5-20 m. Based on the cluster analysis, the study area could be divided into five station groups. The biodiversity, evenness and richness index appeared as follows: H' = 4.28-4.64, E' = 0.74-0.79, R = 33.17-35.45. The dominance index were highest in Sagye and lowest in Sinhung.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.21 no.5
• /
• pp.599-607
• /
• 2015

The purpose of this study is to reproduce long-term wave fields in coastal waters of Korea based on wave hind-casting modelling and discuss its applications. To validate wind data(NCEP, ECMWF, JMA-MSM), comparison of wind data was done with wave buoy data. JMA-MSM predicted wind data with high accuracy. But due to relatively longer period of ECMWF wind data as compared to that of JMA-MSM, wind data set of ECMWF(2001~2014) was used to perform wave hind-casting modelling. Results from numerical modelling were verified with the observed data of wave buoys installed by Korea Meteorological Administration(KMA) and Korea Hydrographic and Oceanographic Agency(KHOA) on offshore waters. The results agree well with observations at buoy stations, especially during the event periods such as a typhoon. Consequently, the wave data reproduced by wave hind-casting modelling was used to obtain missing data in wave observation buoys. The obtained missing data indicated underestimation of maximum wave height during the event period at some points of buoys. Reasons for such underestimation may be due to larger time interval and resolution of the input wind data, water depth and grid size etc. The methodology used in present study can be used to analyze coastal erosion data in conjunction with a wave characteristic of the event period in coastal areas. Additionally, the method can be used in the coastal disaster vulnerability assessment to generate wave points of interest.

• Journal of Environmental Science International
• /
• v.2 no.1
• /
• pp.43-49
• /
• 1993

Concentrations of sulfate and 6-values of sulfate, $({\delta}^{34}SO_4_){pw}$, dissolved In pore waters were measured from the sediment cores of the two different marine environments : deep northeast Pacific (57-1) and coastal Kyunggi Bay of Yellow Sea (57-2) . Sulfate concentration in pore waters decreases with depth at both cores, reflecting sulfate reduction in the sediment columns. However, much higher gradient of pore water sulfate at 57-2 than 57-1 indicates more rapid sulfate reduction at 57-2, because of high sedimentation rate at the coastal area compared to the deep-sea. The measured 6-values, $({\delta}^{34}SO_4_){pw}$, follow extremely well the predicted trend of the Rayleigh fractionation equation. The range of 26.756 to 61.35% at the coastal core 57-2 is not so great as that of 32.4$\textperthousand$ to 97.8$\textperthousand$ at the deep-sea core 57-1. Despite greater graclient of pore water sulfate at 57-2, the 6-values become lower than those of the deep- sea core 57-1. This inverse relation between the 6-values and the gradients of pore water sulfate could be explained by the combination of the two subsequent factors : the kinetic effect by which the residual pore water sulfate becomes progressively enriched with respect to the heavy isotope of $^{34}S$ as sulfate reduction proceeds, and the intrinsic formulation effect of the Rayleigh fractionation equation in which the greater becomes the fractionation factor, the more diminished values of $({\delta}^{34}SO_4_){pw}$ are predicted.

• The Journal of Engineering Geology
• /
• v.13 no.4
• /
• pp.389-404
• /
• 2003

VOCs were detected in the 21 groundwaters out of 37 groundwaters sampled from around the Hanam Industrial Complex and the Gwangju stream. Ten components of chlorinated aliphatic hydrocarbons of VOCs were detected in the 18 groundwater samples. Among them, total trihalomethanes (TTHM) concentration is in the range of $0.1~36.2{\;}\mu\textrm{g}/L$, CECs concentration is $2.3~190{\;}\mu\textrm{g}/L$, and chlorinated solvents concentration containing PCE, TCE, etc. is $0.1~124.2{\;}\mu\textrm{g}/L$ respectively. Ten components of the aromatic hydrocarbons of VOCs were detected in the 5 groundwater samples, but their concentration are less than $1{\;}\mu\textrm{g}/L$. Detection frequency and concentration of the chlorinated aliphatic hydrocarbons components from the groundwaters in the Hanam Industrial Complex are higher than those of nearby downtown Gwangju stream. VOCs components except for TCE are lower than the MCL of USGS drinking water standard. TCE concentration of the 2 groundwater samples is over MCL, whose concentrations are 5 and 25 times higher than MCL, respectively. TCE is detected from the H8 and H10 groundwater samples and CFCs is detected H8 and H11 groundwater samples in the Hanam Industrial Complex. TTHM in study area is estimated from leakage of the main waters or sewage waters. Because most of the studied groundwater is under an aerobic condition, aromatic hydrocarbons are well degraded. But chlorinated aliphatic hydrocarbons are degraded very slowly.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.4
• /
• pp.432-437
• /
• 1999

Age and growth of the marbled rockfish, Sebastiscus marmoratus were studied based on 818 specimens caught from the coastal waters of Cheju Island from July 1992 to July 1993 and from June 1994 to July 1995. According to the monthly changes of marginal increment in each annual ring groups, the ring of otolith was formed in both female and male in February. Relationship between the total body length (TL) and the radius of otolith (R) was estimated, Growth of females was rather slower than that of male in total length; TL=-0.526+4.818R(r=0.847) for female, and TL=-1.895+ 5.239R (r=0.881) for male. The growth curve fits well with Bertalanffy equation: $L_{t}=21.484(1-e^{-0.424(t+0.334)})$ for female and $L_{t}=23.698(1-e^{-0.441(t+0.0589)})$ for male, Growth in weight as follows: $W_t=163.42(1-e^{-0.424(t+0.334)})^3$ for female and $W_t=210.14(1-e^{-0.441(t+0.0589)})^3$ for male.

• Journal of Sericultural and Entomological Science
• /
• v.45 no.2
• /
• pp.90-95
• /
• 2003

This study was carried out to identify of C3G (cyanidin-3-glucoside) from mulberry fruits and quantify with different varieties. C3G of mulberry fruits was extracted with 1％ HCl-MeOH and purified with open column (5${\times}$90cm) which filled with Amberlite IRC-50 ion exchange resin. The $\lambda$max ranges of the purified C3G on UV/vis spectrum were 516nm and 280nm. Also, molecular weight of C3G from mulberry fruits by LC-Mass was determined as 449. From above results, we concluded that anthocyanin pigment of mulberry fruits was C3G only. The cyanidin-3-glucoside (C3G) was separated and quantified by High Performance Liquid Chromatography (HPLC) system using a Nova-Pack C$\_$18/ column. Mean content of the 35 tested accessions was 0.89％. Also fruity characteristics as well as C3G content to select the desirable mulberry varieties for the production of fruit were researched and analyzed. We selected three suitable varieties such as 'Susungppong', 'Kangsun', and 'Jeolgokchosaeng(Chungpuk)'.