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Long-term changes in air and water temperatures and the resulted stratification phenomena were observed for Soyang Lake (SY), Paldang Lake (PD), Chungju Lake (CJ), and Daecheong Lake (DC) in South Korea. Non-parametric seasonal Kendall and Mann-Kendall tests, Sen slope estimator, and potential energy anomaly (PEA) were applied. The lake surface water temperatures (LSWTs) of SY and DC increased at the same rate (0.125 °C/y), followed by those of CJ (0.071 °C/y) and PD (0.06 °C/y). Seasonally, the LSWT increase rates for all lakes, except PD, were 2–3 times higher than the air temperature increase rates. The lake stratification intensity order was similar to those of the LSWT increases and correlations. SY and DC displayed significant correlations between LSWT (0.99) and PEA (0.91). Thus, the LSWT significantly affected stratification when the water temperature increased. PD demonstrated the lowest correlation between LSWT and PEA. Inflow, outflow, rainfall, wind speed, and retention time were significantly correlated, which varied within and between lakes depending on lake topographical, hydraulic, and hydrological factors. Thus, hydraulic problems and nutrients should be managed to minimize their effects on lake water quality and aquatic ecosystems because lake cyanobacteria can increase as localized water temperatures increase.
Soon-Ju Yu; Ju-Yeon Son; Ho-Yeong Kang; Yong-Chul Cho; Jong-Kwon Im. Effects of Long-Term Increases in Water Temperature and Stratification on Large Artificial Water-Source Lakes in South Korea. Water 2021, 13, 2341 .
AMA StyleSoon-Ju Yu, Ju-Yeon Son, Ho-Yeong Kang, Yong-Chul Cho, Jong-Kwon Im. Effects of Long-Term Increases in Water Temperature and Stratification on Large Artificial Water-Source Lakes in South Korea. Water. 2021; 13 (17):2341.
Chicago/Turabian StyleSoon-Ju Yu; Ju-Yeon Son; Ho-Yeong Kang; Yong-Chul Cho; Jong-Kwon Im. 2021. "Effects of Long-Term Increases in Water Temperature and Stratification on Large Artificial Water-Source Lakes in South Korea." Water 13, no. 17: 2341.
Human and veterinary pharmaceuticals are being increasingly used for disease treatment; hence, their distribution and factors influencing them in the aquatic environment need to be investigated. This study observed the effect of human and animal populations, usage, purchasing criteria (prescription vs. non-prescription), and land use to identify the spatio-temporal distribution of eight pharmaceuticals at twenty-four sites of the tributaries of the Han River watershed. In rural areas, the mean concentration (detection frequency) of non-prescription pharmaceuticals (NPPs) was higher (lower) compared to that of prescription pharmaceuticals (PPs); in urban areas, a reverse trend was observed. Pharmaceutical concentrations in urban and rural areas were mainly affected by wastewater treatment plants (WWTPs) and non-point sources, respectively; concentrations were higher downstream (4.9 times) than upstream of the WWTPs. The concentration distribution (according to the target) was as follows: human–veterinary > human > veterinary. Correlation between total concentration and total usage of the pharmaceuticals was high, except for NPPs. Most livestock and land use (except cropland) were significantly positively correlated with pharmaceutical concentrations. Concentrations were mainly higher (1.5 times) during cold seasons than during warm seasons. The results of this study can assist policymakers in managing pharmaceutical pollutants while prioritizing emerging pollutants.
Jong Im; Sang Kim; Young Kim; Soon Yu. Spatio-Temporal Distribution and Influencing Factors of Human and Veterinary Pharmaceuticals in the Tributary Surface Waters of the Han River Watershed, South Korea. International Journal of Environmental Research and Public Health 2021, 18, 7969 .
AMA StyleJong Im, Sang Kim, Young Kim, Soon Yu. Spatio-Temporal Distribution and Influencing Factors of Human and Veterinary Pharmaceuticals in the Tributary Surface Waters of the Han River Watershed, South Korea. International Journal of Environmental Research and Public Health. 2021; 18 (15):7969.
Chicago/Turabian StyleJong Im; Sang Kim; Young Kim; Soon Yu. 2021. "Spatio-Temporal Distribution and Influencing Factors of Human and Veterinary Pharmaceuticals in the Tributary Surface Waters of the Han River Watershed, South Korea." International Journal of Environmental Research and Public Health 18, no. 15: 7969.
Lake Paldang is a complex water system with both fluvial and lacustrine characteristics and the largest artificial dam lake in South Korea. In this study, the different occurrence patterns and causes of the clear-water phase (CWP) were investigated using water quality and hydrological factors at four sites in Lake Paldang. Among the environmental and other factors associated with CWP occurrence, secchi depth and turbidity exhibited significant correlations with precipitation, hydraulic retention time (HRT), and individual and relative abundance (RA) of zooplankton (Cladocera) (p< 0.01). Hence, a change in the HRT because of precipitation could alter the CWP. The Cladocera individuals and RA showed significant correlations with the water temperature, indicating that the emergence of Cladocera in spring as the water temperature rises could cause the CWP. Sensitivity assessments conducted using Bayesian models demonstrated different CWP occurrence sensitivity relationships for the river-type, lake-type, and shallow and deep sites. Turbidity, secchi depth, and zooplankton factors also showed sensitive relationships with CWP occurrence for all sites. The sensitivity to precipitation and HRT was higher in the river-type sites. The lake-type sites, with common Cladocera emergence and long HRT, favored CWP occurrence. Thus, CWP occurrence was dependent on the site characteristics and climate conditions.
Younbo Sim; Myeong Byeon; Keonhee Kim; Soon Yu; Jong Im. Influence of Zooplankton and Environmental Factors on Clear-Water Phase in Lake Paldang, South Korea. International Journal of Environmental Research and Public Health 2021, 18, 7205 .
AMA StyleYounbo Sim, Myeong Byeon, Keonhee Kim, Soon Yu, Jong Im. Influence of Zooplankton and Environmental Factors on Clear-Water Phase in Lake Paldang, South Korea. International Journal of Environmental Research and Public Health. 2021; 18 (13):7205.
Chicago/Turabian StyleYounbo Sim; Myeong Byeon; Keonhee Kim; Soon Yu; Jong Im. 2021. "Influence of Zooplankton and Environmental Factors on Clear-Water Phase in Lake Paldang, South Korea." International Journal of Environmental Research and Public Health 18, no. 13: 7205.
Volatile organic compounds (VOCs), with negative impacts on the aquatic ecosystem, are increasingly released into the environment by anthropogenic activities. Water samples were collected from five areas of the Han River Watershed (HRW) tributaries, South Korea, to detect 11 VOCs, which were classified as halogenated aliphatic hydrocarbons (HAHs) and aromatic hydrocarbons (AHs). Among the 11 VOCs, 1,1-dichloroethylene, 1,1,1-trichloroethane, and vinyl chloride were undetected. The highest concentration compounds were chloroform (0.0596 ± 0.1312 µg/L), trichloroethylene (0.0253 ± 0.0781 µg/L), and toluene (0.0054 ± 0.0139 µg/L). The mean concentration (0.0234 µg/L) and detection frequency (37.0%) of HAHs were higher than those of AHs (0.0036 µg/L, 21.0%, respectively). The Imjin Hantan River area exhibited the highest mean concentration (0.2432 µg/L) and detection frequency (22.9%), because it is located near industrial complexes, thus, highlighting their role as important VOC sources. However, the detected VOCs had lower concentrations than those permitted by the EU, WHO, USA, and South Korea drinking water guidelines. Ecological risks associated with the VOCs were estimated by risk quotient (RQ); consequently, the predicted no-effect concentration was 0.0029 mg/L, and the toluene and styrene RQ values were >1 and >0.5, respectively. The findings may facilitate policymakers in designing pollution control strategies.
Jong-Kwon Im; Yong-Chul Cho; Hye-Ran Noh; Soon-Ju Yu. Geographical Distribution and Risk Assessment of Volatile Organic Compounds in Tributaries of the Han River Watershed. Agronomy 2021, 11, 956 .
AMA StyleJong-Kwon Im, Yong-Chul Cho, Hye-Ran Noh, Soon-Ju Yu. Geographical Distribution and Risk Assessment of Volatile Organic Compounds in Tributaries of the Han River Watershed. Agronomy. 2021; 11 (5):956.
Chicago/Turabian StyleJong-Kwon Im; Yong-Chul Cho; Hye-Ran Noh; Soon-Ju Yu. 2021. "Geographical Distribution and Risk Assessment of Volatile Organic Compounds in Tributaries of the Han River Watershed." Agronomy 11, no. 5: 956.
Increasing public awareness about the aesthetics and safety of water sources has shifted researchers’ attention to the adverse effects of volatile organic compounds (VOCs) on humans and aquatic organisms. A total of 17 VOCs, including 10 volatile halogenated hydrocarbons and seven volatile non-halogenated hydrocarbons, were investigated at 36 sites of the Han River Basin, which is the largest and most important drinking water source for residents of the Seoul metropolitan area and Gyeonggi province in South Korea. The VOC concentrations ranged from below detection limits to 1.813 µg L−1. The most frequently detected VOC was 1,2-dichloropropane, with a detection frequency of 80.56%, as it is used as a soil fumigant, chemical intermediate, and industrial solvent. In terms of geographical trends, the sampling sites that were under the influence of sewage and industrial wastewater treatment plants were more polluted with VOCs than other areas. This observation was also supported by the results of the principal component analysis. In the present study, the detected concentrations of VOCs were much lower than that of the predicted no-effect concentrations, suggesting low ecological risk in the Han River. However, a lack of available ecotoxicity data and limited comparable studies warrants further studies on these compounds.
Jong Im; Soon Yu; Sujin Kim; Sang Kim; Hye Noh; Moon Kim. Occurrence, Potential Sources, and Risk Assessment of Volatile Organic Compounds in the Han River Basin, South Korea. International Journal of Environmental Research and Public Health 2021, 18, 3727 .
AMA StyleJong Im, Soon Yu, Sujin Kim, Sang Kim, Hye Noh, Moon Kim. Occurrence, Potential Sources, and Risk Assessment of Volatile Organic Compounds in the Han River Basin, South Korea. International Journal of Environmental Research and Public Health. 2021; 18 (7):3727.
Chicago/Turabian StyleJong Im; Soon Yu; Sujin Kim; Sang Kim; Hye Noh; Moon Kim. 2021. "Occurrence, Potential Sources, and Risk Assessment of Volatile Organic Compounds in the Han River Basin, South Korea." International Journal of Environmental Research and Public Health 18, no. 7: 3727.
Eight compounds from three categories of pharmaceuticals [5 antibiotics, 2 non-steroidal anti-inflammatory drugs, and 1 anti-epileptics] were monitored at 24 sites in the tributaries of the Han River watershed in South Korea, 2016. The seasonal occurrence, temporal-spatial variation, potential compound source(s), and a risk assessment of this watershed, which is the largest drinking water source in the country, were investigated. Clarithromycin was detected most frequently (72.2%) with the greatest median concentration (0.151 ± 0.072 μg L−1), followed by carbamazepine and sulfamethoxazole. The seasonality of the pharmaceuticals was observed, with higher concentrations and detection frequencies in spring than in summer and autumn; this was possibly caused by lower levels of microbial activities associated with lower water temperatures than other seasons. In terms of geographical variation, urban areas had higher pharmaceutical concentrations than rural areas, which was attributed to the former's high population density and largest wastewater treatment plants (WWTPs) regardless of season. The total concentration and detection frequency of WWTPs were 12.4 and 2.5 times higher in downstream sites than upstream sites, thereby conveying that WWTPs were the main source for the presence of pharmaceuticals in tributaries. According to the results produced from calculations of the risk quotient (RQ) of aquatic organisms, clarithromycin and sulfamethazine were identified as posing relatively high ecological risk (RQ > 1) during the spring that was identified for this study. This study can provide policymakers with scientific support for prioritizing pollutant management and collections of global data on emerging pollutants.
Jong Kwon Im; Sang Hun Kim; Hye Ran Noh; Soon Ju Yu. Temporal-spatial variation and environmental risk assessment of pharmaceuticals in tributaries of the Han River watershed, South Korea. Science of The Total Environment 2020, 741, 140486 .
AMA StyleJong Kwon Im, Sang Hun Kim, Hye Ran Noh, Soon Ju Yu. Temporal-spatial variation and environmental risk assessment of pharmaceuticals in tributaries of the Han River watershed, South Korea. Science of The Total Environment. 2020; 741 ():140486.
Chicago/Turabian StyleJong Kwon Im; Sang Hun Kim; Hye Ran Noh; Soon Ju Yu. 2020. "Temporal-spatial variation and environmental risk assessment of pharmaceuticals in tributaries of the Han River watershed, South Korea." Science of The Total Environment 741, no. : 140486.
The Han River watershed is the largest and most important source of drinking water for the residents of the Seoul metropolitan area and the Gyeonggi province in South Korea. The tributaries of the watershed are vulnerable to contamination by effluents from nearby wastewater treatment plants (WWTPs) and non-point sources. In this study, a one-year monitoring study was performed to investigate the occurrence of 13 pharmaceuticals in 24 tributaries of the Han River watershed in October 2015. From the 13 pharmaceuticals, 12 were found in at least one sample, with the exception of chlortetracycline, which was not detected. The three most frequently detected compounds were clarithromycin (95.8%), carbamazepine (66.7%), and lincomycin (62.5%). Compounds found in high concentrations included clarithromycin (5.2675 μg L−1), ibuprofen (1.9646 μg L−1), and carbamazepine (1.1009 μg L−1). The total concentration of 12 pharmaceuticals in the Seoul metropolitan area (0.7128 μg L−1) was higher than that in the Gyeonggi area (0.3177 μg L−1) possibly due to the large-scale WWTPs located upstream. However, in IHR-3, which is located at the very upstream of the tributary and is not impacted by a WWTP, pharmaceuticals were not detected. This can be explained by the fact that most pharmaceuticals derived from WWTPs are related to human activity. The risk quotients (RQs) for the target pharmaceuticals were calculated on the basis of their presence in tributaries, and all pharmaceuticals presented RQs < 0.01, indicating that potential environmental impacts should be low. These results will be useful to monitor and assess the potential environmental risks of pharmaceuticals in the surface water.
Jong Kwon Im; Moon Young Hwang; Eun Hee Lee; Hye Ran Noh; Soon Ju Yu. Pharmaceutical compounds in tributaries of the Han River watershed, South Korea. Environmental Research 2020, 188, 109758 .
AMA StyleJong Kwon Im, Moon Young Hwang, Eun Hee Lee, Hye Ran Noh, Soon Ju Yu. Pharmaceutical compounds in tributaries of the Han River watershed, South Korea. Environmental Research. 2020; 188 ():109758.
Chicago/Turabian StyleJong Kwon Im; Moon Young Hwang; Eun Hee Lee; Hye Ran Noh; Soon Ju Yu. 2020. "Pharmaceutical compounds in tributaries of the Han River watershed, South Korea." Environmental Research 188, no. : 109758.
In this study, the photo-ozonation reaction for carbamazepine (CBZ) removal was investigated under alkaline conditions. Response surface methodology based on a central composite design was used to obtain the optimum experimental conditions, and examine both main and interaction effects of the photo-ozonation reaction variables such as O3 concentration, H2O2 concentration and UV intensity. The level of O3 concentration significantly influenced CBZ removal (p < 0.001). CBZ removal increased with increasing both O3 and H2O2 concentration up to a certain level, whereas further increase in O3 and H2O2 concentration resulted in an adverse effect due to the hydroxyl radical scavenging effect. The optimum conditions for complete CBZ removal at pH 9 were found to be 0.89 mg of O3 l−1, 4.85 mg of H2O2 l−1 and 3.18 mW of UV intensity cm−2, respectively.
J. K. Im; Kyung-Duk Zoh. Application of response surface method to carbamazepine removal in photo-ozonation reaction under alkaline condition. Water Science and Technology 2013, 67, 74 -81.
AMA StyleJ. K. Im, Kyung-Duk Zoh. Application of response surface method to carbamazepine removal in photo-ozonation reaction under alkaline condition. Water Science and Technology. 2013; 67 (1):74-81.
Chicago/Turabian StyleJ. K. Im; Kyung-Duk Zoh. 2013. "Application of response surface method to carbamazepine removal in photo-ozonation reaction under alkaline condition." Water Science and Technology 67, no. 1: 74-81.