• Journal of Korean Society on Water Environment
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• v.36 no.2
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• pp.116-124
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• 2020

This study aims to identify the characteristics of organic matter and pollutant sources using water quality and stable isotope ratios (δ¹⁵N, δ¹³C) of the two inflow tributaries (Gulpo (GP) and Anyang (AY) streams). Water samples were analyzed in June and September 2018, and the results showed that the concentrations of nutrients, such as TN and NO₃-N, were increased at GP4, which is located at the downstream of sewage treatment facilities(STFs). TOC and TN ratios showed a strong positive correlation (R² = 0.77, p<0.01) at all points except for GP4. The results of GP's stable isotope ratio analysis do not appear to be a constant cluster compared to AY because GPs with large amounts of pollutants from the industry (metal processing companies, etc.) have less tributary, shorter waterway and significantly different external sources. This could be attributed to different sources of external inflow despite its smaller number of tributaries and shorter waterways than AY. In the first half of the year, the δ¹⁵5N of GP4 was affected by discharge of STFs, while AY3 seemed to have an influence of tributary than the discharge of STFs. Consequently, using water quality, stable isotope ratio and C/N, the sources of contamination in two streams with different contaminants were identified and origin was estimated.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.85-88
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• 2003

Polycyclic aromatic hydrocarbons (PARs) are an important group of organic contaminants present in sewage sludge, due to their persistence, toxic, bioaccumulative and long range transfer. These characters make themselves as Persistent Organic Pollutants(POPs) in Long Range Transboundary Air Pollutions convention(LRT AP) of Europe. A method of the gas chromatographic-mass spectrometric (GC-MS) determination of PARs present in sewage sludge was developed and applied to analyzed samples from five sewerage treatment plants (SWTPs), having different treatment types. PARs were extracted from freeze-dried samples by toluene 16 hours in a soxhlet extraction system. The sludge extracts were cleaned-up by an activated silica gel column chromatography. The sum of the 16 US Environmental Protection Agency PARs sewage sludge samples varied from 2.44 to 4.82 ${\mu}g$/g. Concentration of emission carcinogen PARs(PARcarc), such as Benzo(a)anthracene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(a)pyrene, Dibenzo(a, h)anthracene and Indeno(1, 2, 3-cd)pyrene ranged from 0.62 to 1.03 ${\mu}g$/g. The total amount of PAHs emission from sewage sludge in Korea was calculated as a top-down approach. PARs and $\sum$PAHcarc from sewage treatment plants had several pathway each by-products. In the ocean dumping, PAHs and $\sum$PAHcarc emissions were 1155.95 kg/year and 5040.32 kg/year. In recycle, PAHs and $\sum$PAHcarc emissions were 98.36 kg/year and 428.87 kg/year. In the landfill, PAHs and $\sum$PAHcarc emissions were 190.40 kg/year and 830.21 kg/year. In the incineration, PAHs and $\sum$PAHcarc emission were 33.10 kg/year and 830.21 kg/year. (In case of incineration, the whole provisions of PARs and $\sum$PAHcarc contained to flowed in sludge was supposed to be exhausted to environment through exhaust after incineration.)

• Environmental Analysis Health and Toxicology
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• v.10 no.1_2
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• pp.21-35
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• 1995

Risk assessment processes, which include processes for the estimation of human cancer potency using animal bioassay data and calculation of human exposure, entail uncertainties. In the exposure assessment process, exposure scenarios with various assumptions could affect the exposure amount and excess cancer risk. We compared risk estimates among various exposure scenarios of vinyl chloride, trichloroethylene and tetrachloroethylene in tap water. The contaminant concentrations were analyzed from tap water samples in Seoul from 1993 to 1994. The oral and inhalation cancer potencies of the contaminants were estimated using multistage, Weibull, lognormal, and Mantel-Bryan model in TOX-RISK computer software. In the first case, human excess cancer risk was estimated by the US EPA method used to set the MCL(maximum contaminant level). In the second and third case, the risk was estimated for multi-route exposure with and without adopting Monte-Carlo simulation, respectively. In the second case, exposure input parameters and cancer potencies used probability distributions, and in the third case, those values used point estimates(mean, and maximum or 95% upper-bound value). As a result, while the excess cancer risk estimated by US EPA method considering only direct ingestion tended to be underestimated, the risk which was estimated by considering multi-route exposure without Monte-Carlo simulation and then using the maximum or 95% upper-bound value as input parameters tended to be overestimated. In risk assessment for volatile organic compounds, considering multi-route exposure with adopting Monte-Carlo analysis seems to provide the most reasonable estimations.

• Environmental Engineering Research
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• v.20 no.2
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• pp.149-154
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• 2015

In recent years, immobilization agents were introduced into organic contaminated soil remediation and more and more materials were screened and used as the immobilizing carrier. However, effect of the decomposition of the immobilizing carrier on the bioremediation was rarely concerned. Therefore, the decomposition experiment of immobilizing carrier -corncob was carried out in the lab with the efficient degradation fungi - Mucor mucedo (MU) existing, and polycyclic aromatic hydrocarbons (PAHs) residues E4/E6 of the dissolved organic matter and microbial diversity during the decomposition process were studied. The results showed that: a) during the decomposition, the degradation of pyrene (Pyr) was mainly in the first 28 d in which the content of extractable Pyr decreased rapidly and the highest decrease was in the treatment with only MU added. b) Anslysis of E4/E6 changes showed that rich microorganisms could promote aromatization and condensation of humus. c) From the diversity index analysis it can also be seen that there is no significant difference in effects of PAHs on the uniformity of microorganisms. These results will not only be useful to have a better understanding of the bioavailability of contaminants adsorbed to biodegradable carriers in PAHs contaminated soil remediation, but also be helpful to perfect the principle of immobilized microbial technique.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.10
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• pp.975-983
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• 2008

In view of previous investigations that the outermost zone of porous media displays the most vigorous removal of organic contaminant, a novel filtration apparatus of cylinder-shaped porous material (polyester fiber) was applied to the Samcheonji reservoir in Gyeongsan to assess its ability to remove contaminants from reservoir water. The apparent mechanism of purification is that organic pollutant dispersed in the water is collected by the matrix to be degraded by microbes in due course. Data obtained from the experiment appear promising; 19$\sim$27% decrease in COD$_{Cr}$, 37$\sim$43% reduction in COD$_{Mn}$, BOD$_5$ diminution between 67$\sim$81%, 93% decrease in turbidity, and 99% removal of Suspended Solids. The results suggest that this device may be a valuable supplementary means to ameliorate the quality of reservoir water.

• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.185-192
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• 1999

To assess the soil quality of Chonan City, soil analyses were conducted according to the 14 different sampling sites. The soil pH of the agricultural area near the expressway was lower than that of the other farming area, which indicated that this acidification was probably attributed to the acid rain caused by the traffic exhaust gas such as SOx and NOx. Acidification was more severe in the dry farming area than in the rice paddy area. All concentration of 6 different heavy metals (As, Cu, Cd, $Cr^{6+}$, Hg, Pb) and organic contaminants (cyanide, organic-p, PCBs, phenols) were found to be lower than the standard of soil pollution. The concentration of BTEX also lower than the standard of soil pollution. An assessment using the SPI (Soil Pollution Index). which was developed to estimate an overall soil quality, was performed. Each SPC (Soil Pollution Score) were evaluated with the results of the data from this study. The soil quality of most area of Chonan City was determined to Class 1 , which indicated that the soil was healthy.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.742-747
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• 2008

Formaldehyde(HCHO) and total volatile organic compounds(VOCs) can cause adverse health effects to the building occupants and may contribute to symptoms of 'Sick Building Syndrome'. These chemical contaminants are emitted from furnishings and electronic equipments as well as building materials. The purpose of this study is to measure and analyze VOCs and HCHO emission concentration from furnitures composed of wood materials including various chemicals by the large chamber method. This paper presents experiment results on the emission concentration of TVOCs and HCHO released from furnitures, such as bed, kitchen, sofa and table by a large chamber($24m^3$). The temperature and air humidity in the chamber are controlled to $25{\pm}1{\circ}C$ and $50{\pm}5%$ for this experiment. When the air change rate is $0.5hr^{-1}$, the background concentrations within the large chamber are below $50{\mu}g/m^3$ for TVOC, $5{\mu}g/m^3$ for HCHO and individual VOCs. The study is investigated the characterization of the chemical emission TVOC and HCHO concentrations and unknown VOCs from 6 furnitures.

• Environmental Engineering Research
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• v.22 no.2
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• pp.203-209
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• 2017

Innovations in the biofiltration process can provide effective solutions to overcome crucial water pollution problems. The elimination of pollutants is a result of the combined effects of biological oxidation, adsorption and filtration processes. This research aims to evaluate the performance of quartz sand biofiltration for removing total suspended solids, turbidity, color, organic matter, and ammonium from polluted river water and develop an empirical model for designing quartz sand biofilters for the treatment of polluted river water. Experiments were conducted using two biofilter units filled with quartz sand as filter media. A set of experiments were performed to evaluate the effect of hydraulic retention time on biofilter performance in removing water contaminants. The kinetics of organic matter removal were also determined to describe the performance of the biofilter. The results show that biofiltration can significantly remove river water pollutants. Removal efficiency depends on the applied hydraulic retention time. At a hydraulic retention time of two hours, removal efficiencies of total organics, ammonium and total suspended solids were up to 78%, 82%, and 91%, respectively. A model for designing quartz sand biofiltration has been developed from the experimental data.

• Journal of Environmental Science International
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• v.12 no.11
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• pp.1167-1171
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• 2003

Polycyclic aromatic hydrocarbons (PAHs) are an important group of organic contaminants present in sewage sludge, due to their persistence, toxic, bioaccumulative and long range transfer. These characters make themselves as Persistent Organic Pollutants(POPs) in Long Range Transboundary Air Pollutions convention(LRTAP) of Europe. A method of the gas chromatographicmass spectrometric (GCMS) determination of PAHs present in sewage sludge was developed and applied to analyzed samples from five sewerage treatment plants (SWTPs), having different treatment types. PAHs were extracted from freeze-dried samples by toluene 16 hours in a soxhlet extraction system. The sludge extracts were cleaned-up by an activated silica gel column chromatography. The sum of the 16 US Environmental Protection Agency PAHs sewage sludge samples varied from 2.44 to 4.82 $\mu\textrm{g}$/g. Concentration of emission carcinogen PAHs(PAHcarc), such as Benzo(a)anthracene, Benzo(b)f1uoranthene, Benzo(k)f1uoranthene, Benzo(a)pyrene, Dibenzo(a,h)anthracene and Indeno( 1,2,3-cd)pyrene ranged from 0.62 to 1.03 $\mu\textrm{g}$/g. The total amount of PAHs emission from sewage sludge in Korea was calculated as a top-down approach. PAHs and $\Sigma$PAHcarc from sewage treatment plants had emitted to environment by several pathway. The highest amount of emission to the environment was remarked in the ocean dumping(PAHs and $\Sigma$PAHcarc emissions were 1155.95 kg/year and 5040.32 kg/year, respectively).

• Journal of Environmental Policy
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• v.13 no.2
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• pp.65-98
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• 2014

Plastics of the marine environment are broken gradually down into smaller particles by chemical weathering, called "microplastic". Microplastics absorb organic pollutants that are persistent bioaccumulative substances. If marine animals ingested microplastic added to contaminant, it will lead to a bioaccumation through the food web. It eventually destroy health of marine environment and is harmful to marine top predators including humans. Also, Microplastics can impact marine animals by leaching the endocrine disruptor in microplastic itself as well as playing an adsorbent role of organic pollutants. Persistent and bioaccumulative substances in Korea have been regulated in terms of chemical risk but existing regulations largely have been limited in land-based source management of microplastic. Thus, the harmful impact will be increased whether the microplastics absorbed contaminants. To prevent risk of persistent bioaccumulative substances, this study suggests the following: (1) the strict management of microplastic by designating the hazardous substances, (2) expand the use of biodegradable plastic, (3) the effort for reuse and recycle, (4) the expand of microplastic clean-up programs.