Chung J.-Y.,Dong - A University |
Yu S.-D.,National Institute of Environmental Research |
Hong Y.-S.,Dong - A University
Journal of Preventive Medicine and Public Health | Year: 2014
Arsenic is a ubiquitous, naturally occurring metalloid that may be a significant risk factor for cancer after exposure to contaminated drinking water, cigarettes, foods, industry, occupational environment, and air. Among the various routes of arsenic exposure, drinking water is the largest source of arsenic poisoning worldwide. Arsenic exposure from ingested foods usually comes from food crops grown in arsenic-contaminated soil and/or irrigated with arsenic-contaminated water. According to a recent World Health Organization report, arsenic from contaminated water can be quickly and easily absorbed and depending on its metabolic form, may adversely affect human health. Recently, the US Food and Drug Administration regulations for metals found in cosmetics to protect consumers against contaminations deemed deleterious to health; some cosmetics were found to contain a variety of chemicals including heavy metals, which are sometimes used as preservatives. Moreover, developing countries tend to have a growing number of industrial factories that unfortunately, harm the environment, especially in cities where industrial and vehicle emissions, as well as household activities, cause serious air pollution. Air is also an important source of arsenic exposure in areas with industrial activity. The presence of arsenic in airborne particulate matter is considered a risk for certain diseases. Taken together, various potential pathways of arsenic exposure seem to affect humans adversely, and future efforts to reduce arsenic exposure caused by environmental factors should be made. Copyright © 2014 The Korean Society for Preventive Medicine.
Um N.,National Institute of Environmental Research |
Hirato T.,Kyoto University
Hydrometallurgy | Year: 2014
This study describes a hydrometallurgical process to investigate the recovery of lithium from seawater using devised total process including an adsorption process with manganese oxide adsorbent and a precipitation process. First, precipitation experiments on Ca(OH)2, Mg(OH)2, and Mn(OH)2 from CaCl2, MgCl2, and MgCl2 in NaOH-H2O solutions were carried out under various conditions of reaction temperature (25-90 °C), NaOH concentration (7-14 pH), and initial amount of CaCl2, MgCl2, and MnCl2 (10 and 100 mmol/dm3). The obtained results showed that there was a need to divide the precipitation process into two steps based on the precipitation characteristics of the target elements in NaOH (or HCl)-H2O solutions. These two steps consist of a first stage with precipitation of Ca(OH)2, Mg(OH)2, and Mn(OH)2 by NaOH and a second stage with Li2CO3 recovery by neutralization using HCl, carbonation using Na2CO3, and concentration using evaporation. Chemical modeling with OLI-Systems® software was used to interpret the precipitation behavior of target elements in the first and second stages; it was compared with available experimental data and good agreement was found. On the basis of the above data, it was possible to separate Ca, Mg, and Mn under pH values ranging from 11.5 to 12.5 in the first stage after the process of seawater adsorption with manganese oxide adsorbent and to recover crystalline Li2CO3 with high purity (over 99%) carbonated by Na2CO3 in the second stage, involving neutralization by adjusting the pH value in the range of 6-8 and evaporation at 100°C to obtain the product with high yield. © 2014 Elsevier B.V.
Sim W.-J.,Pusan National University |
Lee J.-W.,Pusan National University |
Lee E.-S.,Pusan National University |
Shin S.-K.,National Institute of Environmental Research |
And 2 more authors.
Chemosphere | Year: 2011
Twenty-four pharmaceuticals were measured in wastewater from 12 municipal wastewater treatment plants (M-WWTPs), four livestock WWTPs (L-WWTPs), four hospital WWTPs (H-WWTPs) and four pharmaceutical manufacture WWTPs (P-WWTPs). The total concentration of pharmaceuticals in the influent samples was highest in the L-WWTPs followed by the P-WWTPs, H-WWTPs and M-WWTPs. The effluents had different patterns of pharmaceuticals than their corresponding influents because of the different fate of each compound in the WWTPs. Non-steroidal anti-inflammatory drugs (NSAIDs) were the most dominant in the influents from the M-WWTPs and P-WWTPs, while antibiotics were dominantly detected in the L-WWTP. In the H-WWTP influents, NSAIDs, caffeine and carbamazepine were dominant. In the P-WWTPs, the distribution of pharmaceuticals in the effluents varied with sampling sites and periods. The M-WWTP influents had the highest daily loads, while the effluents showed somewhat similar levels in all source types. © 2010 Elsevier Ltd.
Jung J.H.,Korea Institute of Science and Technology |
Jung J.H.,California Institute of Technology |
Lee J.E.,National Institute of Environmental Research
Atmospheric Environment | Year: 2013
Bioaerosols, including aerosolized bacteria, viruses, and fungi, are associated with public health and environmental problems. One promising control method to reduce the harmful effects of bioaerosols is thermal inactivation via a continuous-flow high-temperature short-time (HTST) system. However, variations in bioaerosol physical characteristics - for example, the particle size and shape - during the continuous-flow inactivation process can change the transport properties in the air, which can affect particle deposition in the human respiratory system or the filtration efficiency of ventilation systems. Real-time particle monitoring techniques are a desirable alternative to the time-consuming process of microscopic analysis that is conventionally used in sampling and particle characterization. Here, we report in situ real-time optical scattering measurements of the physical characteristics of airborne bacteria particles following an HTST process in a continuous-flow system. Our results demonstrate that the aerodynamic diameter of bacterial aerosols decreases when exposed to a high-temperature environment, and that the shape of the bacterial cells is significantly altered. These variations in physical characteristics using optical scattering measurements were found to be in agreement with the results of scanning electron microscopy analysis. © 2013 Elsevier Ltd.
Jung J.H.,Korea Institute of Science and Technology |
Lee J.E.,National Institute of Environmental Research |
Bae G.-N.,Korea Institute of Science and Technology
Journal of Aerosol Science | Year: 2013
Previously, we demonstrated that electrospraying, driven by high-intensity electric fields, can be used to generate stable antimicrobial nanoparticles continuously from ethanolic extracts of natural plant products. In this study, we evaluated the performance of antimicrobial air filters made by these electrosprayed natural-product nanoparticles. As a natural antimicrobial suspension, an ethanolic extract of Sophora flavescens Ait. was sprayed in steady cone-jet mode using our specially designed electrospray system (Jung et al., 2011b). Natural-product nanoparticles with a bimodal size distribution were electrosprayed and deposited continuously onto the surfaces of air filters at various concentrations. The physical (filtration efficiency, pressure drop, and fiber morphology) and biological (antimicrobial efficacy against airborne Staphylococcus epidermidis) characteristics were evaluated. Consequently, although the filter pressure drop increased with the amount of nanoparticles on the filter, the antimicrobial activity was enhanced. Compared with the conventional nebulization process, the filters generated by electrospraying S. flavescens natural-product nanoparticles resulted in more effective removal of S. epidermidis bioaerosols. These results will facilitate the implementation of this new technology to control air quality and protect against hazardous airborne microorganisms. © 2012 Elsevier Ltd.