Jihoon Yang

Molecular approaches for the detection and monitoring of microbial communities in bioaerosols: A review.

Bioaerosols significantly affect atmospheric processes while they undergo long-range vertical and horizontal transport and influence atmospheric chemistry and physics and climate change. Accumulating evidence suggests that exposure to bioaerosols may cause adverse health effects, including severe disease. Studies of bioaerosols have primarily focused on their chemical composition and largely neglected their biological composition and the negative effects of biological composition on ecosystems and human health. Here, current molecular methods for the identification, quantification, and distribution of bioaerosol agents are reviewed. Modern developments in environmental microbiology technology would be favorable in elucidation of microbial temporal and spatial distribution in the atmosphere at high resolution. In addition, these provide additional supports for growing evidence that microbial diversity or composition in the bioaerosol is an indispensable environmental aspect linking with public health.

Nocardioides daejeonensis sp. nov., a denitrifying bacterium isolated from sludge in a sewage-disposal plant.

Strain MJ31(T), a gram-reaction-positive, aerobic, rod-shaped, non-motile bacterium, was isolated from a sludge sample collected at the Daejeon sewage-disposal plant, in South Korea, and characterized in order to determine its taxonomic position. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain MJ31(T) belonged to the genus Nocardioides, appearing most closely related to Nocardioides dubius KSL-104(T) (98.6 % sequence similarity), Nocardioides jensenii DSM 20641(T) (97.6 %), Nocardioides daedukensis MDN22(T) (97.2 %) and Nocardioides mesophilus MSL-22(T) (97.0 %). The chemotaxonomic properties of strain MJ31(T) were consistent with those of the genus Nocardioides: MK-8(H(4)) was the predominant menaquinone, iso-C(16 : 0), iso-C(17 : 0) and C(18 : 1)ω9c were the predominant cellular fatty acids, and the cell-wall peptidoglycan was based on LL-2,6-diaminopimelic acid. The genomic DNA G+C content of strain MJ31(T) was 71.2 mol%. Some differential phenotypic properties and low DNA-DNA relatedness values (<28 %) with the type strains of closely related species indicated that strain MJ31(T) represents a novel species, for which the name Nocardioides daejeonensis sp. nov. is proposed. The type strain is MJ31(T) ( = KCTC 19772(T) = JCM 16922(T)).

Improved RDX detoxification with starch addition using a novel nitrogen-fixing aerobic microbial consortium from soil contaminated with explosives

In this work, we developed and characterized a novel nitrogen-fixing aerobic microbial consortium for the complete detoxification of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Aerobic RDX biodegradation coupled with microbial growth and nitrogen fixation activity were effectively stimulated by the co-addition of starch and RDX under nitrogen limiting conditions. In the starch-stimulated nitrogen-fixing RDX degradative consortium, the RDX degradation activity was correlated with the xplA and nifH gene copy numbers, suggesting the involvement of nitrogen fixing populations in RDX biodegradation. Formate, nitrite, nitrate, and ammonia were detected as aerobic RDX degradation intermediates without the accumulation of any nitroso-derivatives or NDAB (4-nitro-2,4-diazabutanal), indicating nearly complete mineralization. Pyrosequencing targeting the bacterial 16S rRNA genes revealed that the Rhizobium, Rhizobacter and Terrimonas population increased as the RDX degradation activity increased, suggesting their involvement in the degradation process. These findings imply that the nitrogen-fixing aerobic RDX degrading consortium is a valuable microbial resource for improving the detoxification of RDX-contaminated soil or groundwater, especially when combined with rhizoremediation.

State of the Art on Legislation for Subsurface Environment Management in Korea

ABSTRACT Many legislations have been implemented in order to manage the subsurface environment in Korea. However, there wasno control tools for managing subsurface environment so effectively. In this study, many laws and regulations wereanalyzed for extracting Korean subsurface environment management plan. Korean government need to 1) establish thebasic paradigm for building the subsurface space, 2) establish the clear subsurface environment management systems, 3)establish the regulations related with subsurface space compensation, 4) prepare the human health and ecosystem relatedlegislations.Key words : Subsurface environment, Laws, Regulations, Policy implications 1. 서론 2014년부터 2015년까지 연속하여 발생한 땅꺼짐 현상,포트홀 등의 지반 침하 현상으로 인해 국민들의 지중 환경 안전 관련 분야에 대한 관심이 매우 높아졌다. 2015년현재 지반 침하 관련 사고가 발생하는 경우 정부에서는전문가로 구성된 비상대책 위원회를 구성하여 사고의 원인을 조사하고 피해가 확산되지 않도록 조치하고 있다.하지만 지반 침하의 원인이 매우 다양하며 관계 법령이산재되어 있는 등의 제도적 기반 부족으로 인해 전문가의의견이 제대로 수렴되기 어려운 실정이다.또한 이해 관계자 및 책임 소재자에 따라 원인 규명에대한 접근 방식이 달라 원인 규명 자체에도 무척 긴 기간이 소요되고 있다.Lee(2014a)에 의해 크게 네 가지 행위가 지반 침하에주된 영향을 미칠 수 있다고 보고되었다. 첫 번째는 건설시공에 의한 지반 침하 현상이다. 인천 지하철공사 현장인근, 경기도 성남시 신분당선 건설 현장 인근에서 발생한 지반 관련 사고와 연관되어 있다. 두 번째는 광산 활동으로 인한 지반의 붕괴이다. 광산활동을 위해 지반 내 발파작업, 안전 수칙을 위반한 현장운영 등으로 지반이 심각하게 훼손된 경우 빈 공간이 압력을 이겨내지 못하여 지반 침하 현상이 발생할 수 있다.세 번째와 네 번째 지반 침하의 주요 원인은 우수 및지하수에 의한 지반 용해와 지하수위의 저하를 꼽을 수있다. 2015년 3월 강원도 삼척 소재 한 석회석 광산에서는 지반 침하가 심하게 진행되어 보도된 사례가 있다. 석회석 지질에 대한 지반 침하는 지하수의 작용으로 인한자연스러운 현상으로 알려져 있다. 또한 2014년 송파구의석촌 호수 수위저하가 땅꺼짐 현상과 관련이 있다고 보도된 바 있다.이와 같이 지반 침하 현상을 일으키는 다양한 원인 중도심지에서 발생하는 땅꺼짐 현상의 발생원인 1위는 ‘도심지 지반 굴착공사’가 선정되었다. 도심지 기반 굴착공사는 지반 침하의 일차적인 피해 이외에도 수도, 가스, 전력 시설의 파괴를 수반할 수 있기 때문에 더욱 위험한

A Study on the Introduction of Pre-management System to Prevent Soil Contamination by Chemical Accident

Although a number of chemical accidents have been occurred in South Korea, the effective prevention act for soil contamination has not been established so far. To effectively protect soil contamination from chemical accidents, decision support laws and regulations are absolutely essential. Regarding this situation, this study was aimed at diagnosing problems in current chemical safety management and prevention and response system against chemical accidents through analyzing the domestic and foreign causes of chemical accidents and the accident response procedures and finally suggesting policy measures for solving those problems. In order to clarify management of soil contamination by chemical accident, this study suggests the establishment of chemical accident preparedness, response, and making of local chemical management law and policy. This law needs to be supported by a clear management framework to guide government officials and all other stakeholders in the management of soil contamination by chemical accident.