Youngyun Park

Sulfur and oxygen isotopic compositions of the dissolved sulphate in the meteoric water in Chuncheon, Korea

The meteoric water deposited in the Chuncheon area was collected from July 2002 to May 2004 and its chemical and isotopic compositions were analyzed to examine if the isotopic data can help trace the sources of the sulfur pollutant and understand the details of acid formation processes in the air. The chemical compositions of the meteoric water indicate that the sulfate mostly comes from anthropogenic sources. The sulfur isotopic compositions of the dissolved sulfate in the meteoric water (δ34Sso4) vary from 2.6 to 7.5‰ with little seasonal differences, which are significantly different from those of the sulfur in the coal being locally consumed (−4.5 to −0.7‰). This difference indicates that the local coal consumption gives insignificant contribution to the pollutant sulfur in the acid deposition of the area. The relationship between (δ34Sso4) and the concentration of sulfate suggests that the sources of pollutant sulfur are variable and inhomogeneous. The oxygen isotopic compositions of the dissolved sulfate in the meteoric water (δ18O4) range from 9.0 to 17.2‰ which are generally lower in winter than in spring. Comparison between the measured and calculated values of (δ18Oso4) suggests that the oxygen isotopic exchange between sulfite and water occurs before its oxidation to sulfate. The extent of isotopic exchange seems to be not controlled by equilibrium but by kinetic fractionation. The poor correlation between δ34S4) and the oxygen isotopic composition of the meteoric water confinns the disequilibrium nature of the isotopic exchange.

Geochemical properties of groundwater affected by open loop geothermal heat pump systems in Korea

This study was performed to examine the chemical and isotopic compositions of groundwater used in open loop GHP systems and natural groundwater around the open loop GHP systems and to evaluate the influence of open loop GHP systems’ operation on groundwater chemistry in Korea. The water temperature of groundwater used in open loop GHP systems ranged from 6.0 to 37.1°C and decreased by 6.7 to 11.6°C compared with that of natural groundwater around the open loop GHP systems. The pH, EC, Eh, Fe2+, and Mn2+ of the groundwater were not significantly affected by open loop GHP systems’ operation. The groundwaters used in open loop GHP systems showed various water types, such as Ca-HCO3, Ca-Cl, Ca-SO4, and Na-HCO3· Although HCO3- and Cl- concentrations were slightly influenced by open loop GHP systems at some sites, the groundwater chemistry used in the open loop GHP systems did not significantly change at most sites. In addition, carbonate and silica minerals and minerals containing Mn were in undersaturated condition, which indicates that the precipitation of these minerals will not occur. However, some minerals containing Fe, such as Fe(OH)3, goethite, and hematite can be precipitated as scale within these system. In the open loop GHP systems selected in this study, the influence of open loop GHP systems on groundwater chemistry is not revealed sufficiently because of short-term monitoring of groundwater chemistry. However, integrated long-term monitoring is necessary to evaluate influence of open loop GHP systems on groundwater chemistry and to improve our understanding of the environmental impacts related to these systems.

Chemical and isotopic compositions of groundwater and stream water in a heavy agricultural basin of Korea

The chemical and isotopic compositions of groundwater and stream water in the Haean basin, Korea, which have been intensively used for agricultural irrigation, were examined. The field parameters and chemical compositions were typical of relatively uncontaminated waters, except for the agricultural impact. The low EC levels indicated that the waters had not experienced any significant geochemical processes such as water-rock interaction and evaporation. The very similar chemical compositions and ionic ratios were also indicative of fast circulation and good hydraulic connection. The oxygen and hydrogen isotopic compositions of most of the samples in wet and dry seasons showed very similar range which indicated a single source for both waters without any significant geochemical alteration. However, in the wet season, evaporation trends were observed in some groundwaters because of inflow of irrigation return flow from a rice paddy field. The isotopes of both waters were affected by the altitude and amount of precipitation.

A Review on Identification Methods for TCE Contamination Sources using Stable Isotope Compositions

This study was performed to summarize application of δ 13 C, δ 37 Cl and δD of trichloroethylene (TCE) to studies on environmental forensic field regarding identification of TCE sources and evaluation of contribution of TCE to groundwater using data collected from literatures. δ 13 C, δ 37 Cl and δD of TCE give some information regarding sources of TCE because they show specific value according to manufacturing method. Also, TCE do not show a significant isotopic fractionation owing to adsorption and dilution. The isotopic fractionation mainly occurs by biodegradation. In addition, isotopic fractionation factor for TCE is different according to a kind of microorganism participated in biodegradation. However, the isotopic data of TCE have to be applied with chemical compositions of TCE and other hydrogeologic factors because isotopic fractionation of TCE is influenced by various factors.

Status of Community Drinking Water in Korea and Implications for Appropriate Management

ABSTRACT Community drinking water (CDW), mostly naturally flowing groundwater, plays important roles in supplying drinkingwater for urban and rural residents in Korea. Over 1,600 CDW facilities are distributed throughout the country, many ofthem situated in the outskirts of metropolitan cities. A large proportion of Korean people have become dependent onCDW for drinking due to a distrust of piped water’s quality and a strong belief in the special medicinal effects of someCDWs. However, administrative and official management and the control of CDW facilities have been inadequate whencompared with the strict examination and control of commercial bottled water, which is physically treated groundwaterfrom deep bedrock aquifers. In this study, even though signs of anthropogenic contamination were not generally found, thetested chemical compositions of selected CDWs featured high enrichment of some constituents including Ca, Mg, Na, andHCO 3 with natural origins such as water-rock interactions. Careless consumption of particular CDWs, which has noscientific basis, will not guarantee health improvement. Consequently, more intensive management of CDW facilities anda long-term interdisciplinary examination of the health effects of CDWs are needed to effectively protect people’s health.Key words :Community drinking water, Yaksu (medical water), Carbonate, Iron, Anthropogenic contamination

A Study on Hydrochemistry Characteristics of Groundwater and Surface water near a Petroleum Contaminated area

The aim of this study was to examine chemical and isotopic compositions of groundwater and lake water near an area contaminated by petroleum and to evaluate influence of petroleum on them during the period from March to August 2011. In dry season, Ca 2+ and SO4 2� were dominant in the groundwater and lake water and Ca 2+ and HCO3 � were significant in wet season. δ 18 O and δD of the groundwater and lake water were plotted near LMWL (δD = 8.06δ 18 O + 12.5). δ 18 O and δD of the lake water did not show seasonal variation. However, δ 18 O and δD of the groundwater were enriched in wet season compared with those in dry season because of influence of small ponds around wells where evaporation losses were slightly experienced. Redox condition of most lake water was oxidation environment in contact with the atmosphere during the study period. However, redox condition of groundwater was transitional environment in dry season and oxidation environment in wet season because of influence of contaminant such as petroleum. In some groundwater, the concentrations of NO3 � in some groundwater were less than 1 mg/L because of denitrification. Also, NO3 � showed positive correlation with SO4 2� and weak negative correlation with HCO3 � , because of influence of denitrification.

Relationship between Water Levels and TCE Concentrations during Pump-and-Treat Tests for a TCE-Contaminated Aquifer

Pilot tests of a pump and treat system were performed three times in the wet season and two times in the dry season over 139 days in a trichloroethylene (TCE) contaminated aquifer. Both groundwater levels and TCE concentrations were measured at two pumping and five monitoring wells. The measured data were used to examine the relationships between groundwater levels, TCE concentrations, and pumping rates. In the wet season, the groundwater levels and TCE concentrations showed negative correlations at both pumping wells and some of the monitoring wells due to heavy rainfall by dilution. At the other monitoring wells, they showed positive correlations because of influence of a residual TCE around the wells. In the dry season, they had positive correlations at most wells. TCE concentrations were also influenced by the pumping rates in a zone including residual TCE. However, TCE concentrations did not show any correlation with the pumping rates out of the zone.

Water quality impacts of irrigation return flow on stream and groundwater in an intensive agricultural watershed

Irrigation return flow can include contaminants derived from agricultural practices, and then deteriorate the quality of surface and subsurface water within the watershed. Thus, it is important to estimate the effect of irrigation return flow on water chemistry/quality. To do that water samples were collected between November 2004 and December 2005 from stream and groundwater in a small watershed that contains extensive rice paddy fields. The water isotopic compositions represented seasonal variation, particularly in downstream of main channel and the tributary. In April and May, water samples in the downstream and tributary could not be explained by three-component (soil water, groundwater and rainfall) hydrograph separation models (THSM). These results indicated that the stream water was affected by high evaporation and that another water body (e.g. quick return flow) impacted on THSM. Plot of Cl/NO3 and NO3/HCO3 showed that the water chemistry of all water samples was mainly regulated by soil water and groundwater. In addition, the water chemistry was related to water derived from rice paddy fields (WR) and manure. Manure impacted the water chemistry in tributary, one of the shallow groundwaters and the deep groundwaters, whereas that water in downstream was affected by WR. On a plot of δ15NNO3 and δ18ONO3 values, many samples were in a cluster indicative of manure and on a denitrification line. These imply that irrigation return flow characterized by denitrification processes was involved in determining the water chemistry. We suggest that chemical and multi-isotopes approach combined with the THSM is useful to elucidate the sources and processes controlling water chemistry in stream associated with rice paddy fields.

Sources of dissolved ions revealed by chemical and isotopic tracers in the Geum River, South Korea

Water samples were collected in the main channel of the Geum River, South Korea, and measured dissolved elemental concentrations and isotopic compositions of nitrate in order to identify the factors controlling water chemistry. Elemental concentrations significantly increased location-wise after the confluence from urban areas, indicating the changes in solute sources from chemical weathering to anthropogenic inputs such as manure, fertilizers, and sewage. In particular, the effect of sewage input is manifested in the concentrations of Cl−, SO42−, and Na+, while the NO3− concentration is influenced mainly by soil inputs with minor contributions from manure and fertilizer because both δ15N–NO3 and δ18O–NO3 indicate NO3− mostly consists of soil-derived nitrates in the upper reaches but manure/sewage nitrates in the lower reaches. The relative proportion of three factors, Cl−, Ca2++Mg2+, and NO3−, indicates that water chemistry in the upstream is controlled by the soil weathering but that in the downstream by the sewage. Seasonally, water chemistry during summer is dominated by the soil weathering due to the flushing effect but that during winter by the sewage. This study suggests that the relative proportion of three factors can be used for tracing natural and anthropogenic sources in water chemistry.

Salinization and Desalinization of Western and Southern Coastal Groundwaters of Korea: Implication for Agriculture

This study was performed to understand the chemical properties of coastal groundwaters of Korea and to evaluate salinization and desalinization using the chemical compositions of groundwaters, ionic ratios and base cation exchange. Salinization and desalinization frequently occurs in coastal and reclaimed regions, respectively. The reclaimed regions are mainly distributed in western coastal areas, but those are hardly distributed in southern coastal area. Thus, in the western coastal areas, the chemical compositions of groundwaters were mainly affected by salinization by seawater encroachment and desalinization by recharge of fresh water. 33 ~ 37% of the total groundwater samples were affected by seawater, and 6 ~ 15% of the total brackish and saline groundwater samples observed desalinization. However, in the southern coastal areas, the chemical compositions of groundwaters were mainly influenced by salinization (approximately 30 ~ 34%). Also, desalinization processes were observed in some southern groundwater samples (approximately 2 ~ 4%). While the desalinization in the western coastal groundwater was mainly observed in reclaimed regions, desalinization in the southern coastal groundwater was not observed in only reclaimed region. This study shows that desalinization can be one of main factors controlling the chemical compositions of groundwaters in the coastal areas including reclaimed regions and base cation exchange is good tool to identify desalinization.