• 상하수도학회지
• /
• 제32권5호
• /
• pp.389-398
• /
• 2018

A nationwide survey of 8 N-nitrosamines in finished water samples from drinking water treatment plants (DWTPs) in Korea was conducted. The samples were pre-treated by solid-phase extraction (SPE) and analyzed using a gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). According to the study results, four N-nitrosamines (NDMA, NDEA, NMOR, NDBA) were detected for three consecutive years, NMEA and NPYR were only found in samples collected in 2013. Two of these N-nitrosamines, N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), have received attention and were the most commonly detected. The concentration of NDMA and NDEA in this study ranged from $0.002{\mu}g/L$ to $0.013{\mu}g/L$ and in $0.001{\mu}g/L$ to $0.008{\mu}g/L$, respectively. In comparison to studies performed in EPA(UCMR2), the concentrations of NDMA (from $0.002{\mu}g/L$ to $0.630{\mu}g/L$) and NDEA (from $0.005{\mu}g/L$ to $0.100{\mu}g/L$) observed in the this study were low.

• 한국물환경학회지
• /
• 제23권1호
• /
• pp.12-18
• /
• 2007

Difference of total coliforms (TC) survival time of mixed samples (effluent were mixed by seawater or freshwater) were examined in various conditions. The time taken to achieve a 90% reduction in the TC concentration ($T_{90}$) of effluent, high initial TC concentration and low initial TC concentration samples indicated 143.9, 121.9 and 89.6 hours at $25^{\circ}C$, respectively. At $4^{\circ}C$, log removal rate after 336 hours were 0.96, 1.04, and 1.30. TC survival time of effluent-inoculated seawater sample was longer than that of effluent-inoculated freshwater sample in laboratory. At outdoor condition, TC inactivation curves of effluent-inoculated seawater or freshwater samples showed similar patterns. And both of them were greatly influenced by climate condition. There was not enough evidence that TC survived longer in freshwater than sea water. It was unlikely that the salinity of sea water contributed to the inactivation process of TC.

• 한국환경농학회지
• /
• 제23권4호
• /
• pp.251-257
• /
• 2004

Analytical methods were developed to determine cyclosulfamuron residues in soil, water, rice grain and straw using high-performance liquid chromatography (HPLC) with ultraviolet absorption detection. In these methods, cyclosulfamuron was extracted with aqueous $Na_2HPO_4$/acetone and acetone/methanol mixture from soil and rice samples respectively. Liquid-liquid partition coupled with ion-associated technique, Florisil column chromatography, and solid-phase extraction (SPE) were used to separate cyclosulfamuron from interfering co-extractives prior to HPLC analysis. For water sample, the residue was enriched in $C_{18}$-SPE cartridge, cleaned up in situ, and directly subjected to HPLC. Reverse-phase HPLC under ion-suppression was successfully applied to determine cyclo-sulfamuron in sample extracts with the detection at its ${\lambda}_{max}$ (254 nm). Recoveries from fortified samples averaged $87.8{\pm}7.1%$ (n=12), $97.3{\pm}7.2%$ (n=12), $90.8{\pm}6.6%$ (n=6), and $78.5{\pm}6.7%$ (n=6) for soil, water, rice grain and straw, respectively. Detection limits of the methods were 0.004 mg/kg, 0.001 mg/L, 0.01 mg/kg and 0.02 mg/kg for soil, water, rice grain and straw samples, respectively.

• 한국환경보건학회지
• /
• 제7권1호
• /
• pp.33-41
• /
• 1981

This study was carried out to investigate Water Temperature, Residual Chlorine, Coliform Groups, and the Standard Plate Counts of Water Supply Areas provided by 7 Water Purification Plant (W.P.P) in Seoul from September 20, 1979 through October 20, 1979. The results were summarized below: 1) The mean water temperature of the 63 Water Samples was 19.8$\circ$C, the mean pH 7.18, and the mean residual chlorine concentration 0.52 ppm by each Water Supply Areas. There is no statistically significant differences between the WPP Areas, but there is significant differences between water supply areas. 2) 30(47.6%) out of the 63 Water Samples were Standard Plate Counts free and 33 Samples (52.4%) were contaminated by Standard Plate Counts. 30 (47.6%) out of 33 samples showed the existence of Standard Plate Counts less than 15 and the other 3 samples 15-30. 3) 2 (3.2%) out of the 63 Samples had the coliform. Those 2 Samples had 2 and 6 coliform group counts per 50ml respectively both of them were 0.1ppm in residual chlorine. 4) There is correlation among Water Temperature, pH, Residual Chlorine, Standard Plate Counts, and Coliform Groups. The Coefficient of Correlation(r) between Water Temperature & Residual Chlorine was 0.147, 0.240 between Water Temperature & Standard plate Counts and 0.215 between pH & Standard Plate Counts. These correlations are statistically no significant, But the correlation of coefficient between pH & Residual Chlorine was -0.291 which is showed significant correlation at p<0.05. The coefficient of correlation between Residual Chlorine & Standard Plate Counts was -0.441 which is showed Negative Correlation Statistically Significant difference at p<0.01.

• 상하수도학회지
• /
• 제26권6호
• /
• pp.757-766
• /
• 2012

In this study, we have examined concentration distribution and patterns of PCBs in waters, sediments and soils in an agricultural area of South Korea to investigate the relationship between PCBs sources and concentration levels. The concentration of PCBs in water samples were ranged from lower values below detection limit to 8.25 ug/L and the concentration of PCBs in sediment samples were ranged from lower values below detection limit to 76.67 ug/Kg. The concentration of PCBs in soil samples were ranged from lower values below detection limit to 23.51 ug/Kg. These contamination levels were far below the guideline values suggested for environmental quality assessment. The homologue patterns in samples varied from sample to sample, but isomer patterns were very similar with each other. PCB-138 and PCB-153 were predominant congeners in the soil and sediment, which were similar to the results obtained from previous studies. With these results, the assessment of potential sources of PCBs contamination in the sediments of the Nakdong river basin was performed. The principal components were extracted by Principal Component Analysis(PCA). As the result of PCA, it could be expected that PCBs in samples of this study were more affected by PCB products than combustion processes and mostly affected by already-known sources. The PCBs in the soil and sediment samples were related with commercial PCB products.

• 한국환경보건학회지
• /
• 제25권3호
• /
• pp.1-6
• /
• 1999

This study was conducted to survey trihalomethane(THMs) levels in finished water of J water treatment plant and examine its reduction by powder activated carbon(PAC) treatment. Samples were collected weekly based and head-space technique was employed to determine THMs levels by G.C-ECD. THMs levels in finished waters were highest in August and showed close relationship with water temperature. All the samples satisfied the drinking water limit(100 ${\mu}$g/l) for THMs. The individual formation rates of THMs were 64.8% for CHCl$_3$, 28.4% for CHCl$_2$BR, 6.5% for CHClBr$_2$ and 0.3% for CHBr$_3$, respectively and showed little monthly difference. The reduction efficiency of THMs formation by PAC treatment was 67% during July and August. Bromine substituents were more efficiently reduced than CHCl$_3$ by PAC.

• 한국환경보건학회:학술대회논문집
• /
• 한국환경보건학회 2004년도 International Conference Global Environmental Problems and their Health Consequences
• /
• pp.197-201
• /
• 2004

This study was to determine the prevalence of Legionella species in public spas and to know that the presence of Legionella was correlated with other microbiological parameters. A total of 81 water samples were collected from 30 different public spas and sudatoriums so called zzimzilbang in Korea. Although Legionella was not detected in the influent water and the cold tub water, of the 38 samples of hot and warm water taken from public tubs, 11(28.8%) were found to be positive for Legionella spp. All of the isolates were identified as a species L. pneumophila serogroups 1 and 2-14 by latex agglutination. And HPC concentrations in all spas water isolated Legionella were above the level of $10^4\;cfu/ml$.

• 한국환경보건학회:학술대회논문집
• /
• 한국환경보건학회 2003년도 Challenges and Achievements in Environmental Health
• /
• pp.132-135
• /
• 2003

Endotoxin concentrations were measured from 69 point-of-use(POU) water treatment system(WTS) by using Limulus amebocyte lysate(LAL) assay, and the results were compared to heterotrophic bacterial data. Endotoxin concentrations in all POU WTS water samples and tap waters varied within the range 0.8-79.1EU mL$\^$-1/ and 0.1-3.4EU mL$\^$-1/, respectively, The correlations between endotoxin concentration and HPC bacteria from the water samples showed not significant(r=0.18).

• 상하수도학회지
• /
• 제36권2호
• /
• pp.81-95
• /
• 2022

The present study was performed to investigate the effects of NH₃-N and nitrifying microorganisms on the increased BOD of downstream of the Yeongsan river in Gwangju. Water samples were collected periodically from the 13 sampling sites of rivers from April to October 2021 to monitor water qualities. In addition, the trends of nitrogenous biochemical oxygen demand (NBOD) and microbial clusters were analyzed by adding different NH₃-N concentrations to the water samples. The monitoring results showed that NH₃-N concentration in the Yeongsan river was 22 times increased after the inflow of discharged water from the Gwangju 1st public sewage treatment plant (G-1-PSTP). Increased NH₃-N elevated NBOD levels through the nitrification process in the river, consequently, it would attribute to the increase of BOD in the Yeongsan river. Meanwhile, there was no proportional relation between NBOD and NH₃-N concentrations. However, there was a significant difference in NBOD occurrence by sampling sites. Specifically, when 5 mg/L NH₃-N was added, NBOD of the river sample showed 2-4 times higher values after the inflow of discharged water from G-1-PSTP. Therefore, it could be thought other factors such as microorganisms influence the elevated NBOD levels. Through next-generation sequencing analysis, nitrifying microorganisms such as Nitrosomonas, Nitroga, and Nitrospira (Genus) were detected in rivers samples, especially, the proportion of them was the highest in river samples after the inflow of discharged water from G-1-PSTP. These results indicated the effects of nitrifying microorganisms and NH₃-N concentrations as important limiting factors on the increased NBOD levels in the rivers. Taken together, comprehensive strategies are needed not only to reduce the NH₃-N concentration of discharged water but also to control discharged nitrifying microorganisms to effectively reduce the NBOD levels in the downstream of the Yeongsan river where discharged water from G-1-PSTP flows.

• 한국환경복원기술학회지
• /
• 제13권2호
• /
• pp.42-51
• /
• 2010

Herbs and shrubs are employed for environmental restoration purposes. Among common herbs and shrubs, few species with low germination rates were selected and studied for enhanced germination rates and decreased germination times via soaking treatment. Rhus chinensis, incubator grown samples treated with the bacterial solution for 72hrs followed by immediate seeding showed the highest germination rate of 26.7% and germination period of 5.7 days, 3 days decrease from the control. Treatment of distilled water (t=3.79, p<0.01), nutrient broth (t=4.44, p<0.00) and bacterial solution (t=4.42, p<0.00) showed highly significant difference. In the case of soil tests, treating in the nutrient broth for 72 hrs followed by immediate seeding yielded the the highest germination rate of 23.3% with 7.3 days to initial germination, a decrease of 14.7 days with respect to the control. All the samples followed by immediate seeding showed significant difference (t=2.13, p<0.05). Incubator grown samples of Lespedeza cyrtobotrya showed different results. The incubator samples suspended for 48 hrs in distilled water followed by immediate seeding and 1 day drying displayed the highest germination rate of 96.7%, surpassing that of the control by 33.4%. The incubator samples treated with the distilled water and nutrient broth showed enhanced germination. But only the samples treated with distilled water and nutrient broth for 48hrs showed the increased germination in soil tests. All the sample treated for 24 hrs followed by immediate seeding or dried for 1 day showed initial germination as early as 1 day in incubator. The initial germinations were shortened in the samples treated with distilled water and nutrient broth for 48hrs in soil tests. Lespedeza cuneata incubator sample treated with nutrient broth for 24 hrs and dried for 1 day exhibited the highest germination rate of 83.3%, a 31.1% improvement over the control. The incubator samples treated with distilled water for 48 hrs (t=4.20, p<0.01) showed effective increase of germination. The treatment of distilled water (t=2.96, p<0.05) and bacterial solution (t=2.24, p<0.05) showed significant difference. The germination rates in soil were less than those of incubator and the control. The incubator samples treated with distilled water and bacterial solution displayed 1 day germination period, shortened by 1.3 days compared to the control. For soil grown samples, the samples treated with distilled water showed delayed initial germination and those treated with nutrient broth for 48hrs and bacterial solution for 72hrs shortened initial germination.