Jeong S.,Korea Basic Science Institute |
Yang K.,Korea Environmental Institute |
Jho E.H.,Hankuk University of foreign Studies |
Nam K.,Seoul National University
Journal of Hazardous Materials | Year: 2017
Bioaccessible concentrations of As associated with Fe oxide as different chemical binding types were determined in soils using the in vitro Physiologically Based Extraction Test (PBET). When compared to the five-step sequential extraction data, most of the As extracted by in vitro PBET originated from the amorphous Fe oxide-bound fraction, and more importantly, the bioaccessibility of As ranged from 0 to 58.8% in 24 soil samples. Two batches of ferrihydrite were synthesized separately. For one batch, As was adsorbed onto the ferrihydrite after synthesis; for the other one, As was added while synthesizing ferrihydrite to co-precipitate. The bioaccessible concentration of As determined by in vitro PBET of the former was 415 mg of As/kg of ferrihydrite and that of the latter was 67 mg of As/kg of ferrihydrite. X-ray photoelectron spectra (XPS) analysis indicated that As–O–Fe bonds were evident in As-associated ferrihydrite sample and especially, As was found within the Fe oxide lattice in the co-precipitated sample. Our data suggest that binding type between As and Fe oxide should be considered when determining the bioaccessibility of As in soil, which, in turn, greatly influences the realistic risk of As present in soil. © 2017 Elsevier B.V.
Yang K.,Korea Environmental Institute |
Kim B.-C.,Seoul National University |
Nam K.,Seoul National University |
Choi Y.,Seoul National University
Environmental Science and Pollution Research | Year: 2017
This study investigated the effect of chemical forms of arsenic (As) and soil-magnetite mixing regimes on As mass transfer in magnetite-amended soil. Two soil samples with different component ratios of As chemical forms were prepared. In the absence of magnetite, the amount of desorbable As was strongly dependent on the fraction of easily extractable As in soil. Contact of the soils with magnetite in a slurry phase significantly reduced soil As concentration for both soils. Changes in As concentrations in soil, magnetite, and water by the slurry phase contact were simulated using an As mass transfer model. The model parameters were determined independently for each process of As soil desorption and magnetite sorption. The experimentally measured As mass transfer from soil to magnetite was significantly greater than the simulation result. By sequential extraction, it was observed that the soil As concentration was significantly reduced not only for easily extractable As, but also for relatively strongly bound forms of As. Enclosing the magnetite in a dialysis bag substantially limited the As mass transfer from soil to magnetite. These results suggest that improving the mixture between Fe oxides and soils can facilitate the effectiveness of As stabilization using Fe oxides. © 2017 Springer-Verlag Berlin Heidelberg
Yoo J.-W.,Korea Institute of Coastal Ecology Inc. |
Lee Y.-W.,Fish Program |
Ruesink J.L.,University of Washington |
Lee C.-G.,Korea Institute of Coastal Ecology Inc. |
And 8 more authors.
Environmental Monitoring and Assessment | Year: 2010
The coast of the Korean peninsula experiences a range of human impacts, including pollution, shipping, reclamation, and aquaculture, that have motivated numerous local studies of macrobenthic organisms. In this paper, 1,492 subtidal stations were compiled from 23 studies (areas) to evaluate environmental quality on a broader scale. A common index in biomonitoring, Shannon-Wiener evenness proportion (SEP), could not incorporate azoic or single-species samples. This shortcoming was overcome by developing an inverse function of SEP (ISEP), which was positively correlated with independent measures of water quality available for nine sites and was not biased by the size of the sampling unit. Additionally, at Shihwa Dike, where samples were collected before and after reinstating a tidal connection with the ocean, ISEP values improved over time, as expected. Thus, it is now possible to assign Korean subtidal sites to seven ISEP "grades" and to use their values and trends to guide coastal management. © 2009 Springer Science+Business Media B.V.
PubMed | Dongduk Women's University, University of Seoul, Korea Environmental Institute and Hoseo University
Type: | Journal: Environmental health and toxicology | Year: 2014
Effects of nanoparticles including zinc oxide nanoparticles, titanium oxide nanoparticles, and their mixtures on skin corrosion and irritation were investigated by using in vitro 3D human skin models (KeraSkin ((TM)) ) and the results were compared to those of an in vivo animal test.Skin models were incubated with nanoparticles for a definite time period and cell viability was measured by the 3-(4, 5-dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide method. Skin corrosion and irritation were identified by the decreased viability based on the pre-determined threshold.Cell viability after exposure to nanomaterial was not decreased to the pre-determined threshold level, which was 15% after 60 minutes exposure in corrosion test and 50% after 45 minutes exposure in the irritation test. IL-1 release and histopathological findings support the results of cell viability test. In vivo test using rabbits also showed non-corrosive and non-irritant results.The findings provide the evidence that zinc oxide nanoparticles, titanium oxide nanoparticles and their mixture are non corrosive and non-irritant to the human skin by a globally harmonized classification system. In vivo test using animals can be replaced by an alternative in vitro test.
PubMed | University of Seoul, Dongduk Women's University, Korea Environmental Institute and Hoseo University
Type: | Journal: Environmental health and toxicology | Year: 2015
The widely promising applications of graphene nanomaterials raise considerable concerns regarding their environmental and human health risk assessment. The aim of the current study was to evaluate the toxicity profiling of graphene family nananomaterials (GFNs) in alternative in vitro and in vivo toxicity testing models.The GFNs used in this study are graphene nanoplatelets ([GNPs]-pristine, carboxylate [COOH] and amide [NH2]) and graphene oxides (single layer [SLGO] and few layers [FLGO]). The human bronchial epithelial cells (Beas2B cells) as in vitro system and the nematode Caenorhabditis elegans as in vivo system were used to profile the toxicity response of GFNs. Cytotoxicity assays, colony formation assay for cellular toxicity and reproduction potentiality in C. elegans were used as end points to evaluate the GFNs toxicity.In general, GNPs exhibited higher toxicity than GOs in Beas2B cells, and among the GNPs the order of toxicity was pristine>NH2>COOH. Although the order of toxicity of the GNPs was maintained in C. elegans reproductive toxicity, but GOs were found to be more toxic in the worms than GNPs. In both systems, SLGO exhibited profoundly greater dose dependency than FLGO. The possible reason of their differential toxicity lay in their distinctive physicochemical characteristics and agglomeration behavior in the exposure media.The present study revealed that the toxicity of GFNs is dependent on the graphene nanomaterials physical forms, surface functionalizations, number of layers, dose, time of exposure and obviously, on the alternative model systems used for toxicity assessment.
Bosch N.S.,Grace College |
Allan J.D.,University of Michigan |
Dolan D.M.,University of Wisconsin - Green Bay |
Han H.,Korea Environmental Institute |
Richards R.P.,Heidelberg University
Journal of Great Lakes Research | Year: 2011
The Soil and Water Assessment Tool (SWAT), a physically-based watershed-scale model, holds promise as a means to predict tributary sediment and nutrient loads to the Laurentian Great Lakes. In the present study, model performance is compared across six watersheds draining into Lake Erie to determine the applicability of SWAT to watersheds of differing characteristics. After initial model parameterization, the Huron, Raisin, Maumee, Sandusky, Cuyahoga, and Grand SWAT models were calibrated (1998-2001) and confirmed, or validated (2002-2005), individually for stream water discharge, sediment loads, and nutrient loads (total P, soluble reactive P, total N, and nitrate) based on available datasets. SWAT effectively predicted hydrology and sediments across a range of watershed characteristics. SWAT estimation of nutrient loads was weaker although still satisfactory at least two-thirds of the time across all nutrient parameters and watersheds. SWAT model performance was most satisfactory in agricultural and forested watersheds, and was less so in urbanized settings. Model performance was influenced by the availability of observational data with high sampling frequency and long duration for calibration and confirmation evaluation. In some instances, it appeared that parameter adjustments that improved calibration of hydrology negatively affected subsequent sediment and nutrient calibration, suggesting trade-offs in calibrating for hydrologic vs. water quality model performance. Despite these considerations, SWAT accurately predicted average stream discharge, sediment loads, and nutrient loads for the Raisin, Maumee, Sandusky, and Grand watersheds such that future use of these SWAT models for various scenario testing is reasonable and warranted. © 2011 Elsevier B.V.
Kim H.-K.,Korea Institute of Energy Research |
Kim H.-K.,Hanyang University |
Jeong J.-Y.,Hanyang University |
Cho H.-N.,Hanyang University |
And 2 more authors.
Separation and Purification Technology | Year: 2015
This study investigated the kinetics of nitrate reduction with the zero-valent iron bipolar (ZVI-BP) electrode. The kinetics of the nitrate reduction was considered with respect to the initial concentration of nitrate and the flow rate. Increasing the initial concentration of nitrate enhanced the nitrate reduction rate and there was the proper flow rate (20 mL/min) to achieve the highest nitrate reduction rate (6.2 h-1). But increasing the initial nitrate concentration rather decreased conversion ratio of nitrate to ammonia from 54.5% to 45.9% because of the ammonia oxidation to nitrogen gas as electro-catalytic oxidation. The highest reaction rate was obtained when the experimental hydraulic retention time (HRT) was analogous to the theoretical HRT. The current efficiency was over 100% because of low current density and the redox reaction with Fe2+/Fe3+ redox couple. The corrosion of the ZVI-BP electrodes was characterized by using the X-ray Diffraction (XRD) and the field emission scanning electron microscope (FE-SEM). Magnetite was the major corrosion product and it had potential to enhance the nitrate reduction. The modeling of nitrate reduction had similar trend with experimental data and the verification of the modeling parameter will help the up-scale design of the system. © 2015 Elsevier B.V. All rights reserved.
Son J.,XVT |
Park Y.,Korea Environmental Institute |
Choung T.,University of Seoul |
Choen H.,University of Seoul
42nd International Congress and Exposition on Noise Control Engineering 2013, INTER-NOISE 2013: Noise Control for Quality of Life | Year: 2013
Predicted noise level has been used to assess the annoyance response since noise map was generalized and being the normal method to assess the environmental noise. Unfortunately using predicted noise level for the annoyance prediction curve caused some problems. The datum has to be grouped manually to use the annoyance prediction curve. So the aim of this paper is to propose the method to handle the predicted noise level and the survey data for annoyance prediction curve. This paper used the percentage of persons annoyed(%A) and the percentage of persons highly annoyed(%HA) as the descriptor of noise annoyance in a population. The logistic regression method was used for deriving annoyance prediction curve. It is concluded that the method of dichotomizing data and logistic regression was suitable to handle the predicted noise level and survey data.
Han H.,Korea Environmental Institute |
Allan J.D.,University of Michigan |
Bosch N.S.,Grace College
Journal of Great Lakes Research | Year: 2012
Phosphorus (P) applied to croplands in excess of crop requirements has resulted in large-scale accumulation of P in soils worldwide, leading to freshwater eutrophication from river runoff that may extend well into the future. However, several studies have reported declines in surplus P inputs to the land in recent decades. To quantify trends in P loading to Lake Erie (LE) watersheds, we estimated net anthropogenic phosphorus inputs (NAPI) to 18 LE watersheds for agricultural census years from 1935 to 2007. NAPI quantifies anthropogenic inputs of P from fertilizer use, atmospheric deposition and detergents, as well as the net exchange in P related to trade in food and feed. Over this 70-year period, NAPI increased to peak values in the 1970s and subsequently declined in 2007 to a level last experienced in 1935. This rise and fall was the result of two trends: a dramatic increase in fertilizer use, which peaked in the 1970s and then declined to about two-thirds of maximum values; and a steady increase in P exported as crops destined for animal feed and energy production. During 1974-2007, riverine phosphorus loads fluctuated, and were correlated with inter-annual variation in water discharge. However, riverine P export did not show consistent temporal trends, nor correlate with temporal trends in NAPI or fertilizer use. The fraction of P inputs exported by rivers appeared to increase sharply after the 1990s, but the cause is unknown. Thus estimates of phosphorus inputs to watersheds provide insight into changing source quantities but may be weak predictors of riverine export. © 2012 International Association for Great Lakes Research.
Ahn J.H.,Korea Environmental Institute
Desalination and Water Treatment | Year: 2012
Particle size spectra of suspended sediment eroded from the Santa Ana River, a human-impacted urban river in southern California are investigated to consider fractal behaviors in suspended sediment transport. Widespread urbanization has fueled hydrological change of the water- shed over four decades, showing significant increases in storm water runoff with decreases in instantaneous suspended sediment concentration. In-site observation of particle size distributions (PSDs) during three storm studies reveals two transport regimes (flow-controlled or bed- controlled) depending on whether average particle size increase (flow-controlled) or decrease (bed-controlled) with flow rate. Despite their complexity, the observed PSDs exhibit power-law mass-size statistics, and satisfy fractal (power-law) scaling in a very robust manner. The evolution of PSD to a stable form with asymptotic behavior in suspended sediments suggests that shedding of suspended sediments in urban watershed environment system has its own self- organized characteristics wherever the sediment source come from. © 2012 Desalination Publications. All rights reserved.