• Korean Journal of Mineralogy and Petrology
• /
• v.33 no.3
• /
• pp.233-242
• /
• 2020

As studies and developments of nano-material increase, the release of the nano-sized material to water environment increase. Especially, silver nanoparticles have been found as dissolved and particulate state since nano-silver particle have been intensively used in industrial and our living environment due to the anti-bacterial effect of the nano-particles. The silver nano-particles and silver ion gives adverse effect on ecology and US-EPA set a secondary drinking water standards as 0.1 mg/L. Current study focused on the analysis of silver in groundwater, small scale water supply systems in Gyeongbook area. The results have been compared with the secondary drinking water standards and discussed at the point of characteristics of the local area and purpose of use of the water sample. Among the total of 298 samples, 2 samples exceed the secondary drinking water standards of EPA, 0.64% rate. Community drinking water and simplified water service showed relatively high detection rate and groundwater gave relatively higher concentration of silver indicating anthropogenic source and natural source could contribute simultaneously on groundwater.

• The Journal of Engineering Geology
• /
• v.29 no.4
• /
• pp.495-508
• /
• 2019

We measured the concentrations of natural radionuclides (uranium and radon) and major elements in groundwater collected from forty wells located in Wonju area to investigate the hydrochemistry and the occurrence of these radionuclides. The range of electrical conductivity (EC) value in the study area was 73~400 μS/cm. In addition to the increase of EC value, the content of cations and anions also tends to increase. Uranium concentrations ranged from 0.06~50.5 ㎍/L (median value, 1.55 ㎍/L) and radon concentrations ranged from 67~8,410 pCi/L (median value, 1,915 pCi/L). Uranium concentrations in 3 well, 7.5% of the samples, exceeded 30 ㎍/L, the maximum contaminant level (MCL) proposed by the US Environmental Protection Agency (EPA), based on the chemical toxicity of uranium. Radon concentrations in 9 wells, 22.5% of the samples, and 1 well, 2.2% of the samples, exceeded 4,000 pCi/L (AMCL of the US EPA) and 8,100 pCi/L (Finland's guideline level), respectively. Concentrations of uranium and radon related to geology of the study area showd the highest values in groundwater of the biotite granite area. Uranium and radon contents in the groundwater are comparatively low compared to those in other countries with similar geological settings. It is likely that the measured value was lower than the actual content due to the inflow of shallow groundwater by the lack of casing and grouting.

• Economic and Environmental Geology
• /
• v.51 no.6
• /
• pp.553-566
• /
• 2018

The occurrence of natural radionuclides like uranium and radon in groundwater was hydrochemically examined based on 40 well groundwaters in Mungyeong area. The range of electrical conductivity (EC) value in the study area was $68{\sim}574{\mu}S/cm$. In addition to the increase of EC value, the content of cations and anions also tends to increase. Uranium concentrations ranged from $0.03{\sim}169{\mu}g/L$ (median value, $0.82{\mu}g/L$) and radon concentrations ranged from 70~30,700 pCi/L (median value, 955 pCi/L). Only 1 out of 40 wells (2.5%) showed uranium concentration exceeding the maximum contaminant level (MCL; $30{\mu}g/L$) proposed by the US Environmental Protection Agency (EPA). Radon concentrations of eight wells (20%) exceeded AMCL(Alternative maximum contaminant level) of the US EPA (4,000 pCi/L). Four out of those eight wells even exceeded Finland's guideline level (8,100 pCi/L). When concentrations of uranium and radon were investigated in terms of geology, the highest values are generally associated with granite. The uranium and radon levels observed in this study are low in comparison to those of other countries with similar geological settings. It is likely that the measured value was lower than the actual content due to the inflow of shallow groundwater by the lack of casing and grouting.

• Journal of Korean Society of Environmental Engineers
• /
• v.33 no.3
• /
• pp.202-211
• /
• 2011

In this study the seasonal and spatial pattern of mercury (Hg) concentrations in multimedia environments were investigated in Lake So-Yang. Total mercury (TM) in water column greatly enhanced as turbidity and particulate organic carbon (POC) increased due to the severe runoff, suggesting that most of Hg existed as particulate Hg in Lake Soyang. We also collected 22 species of fish in Lake Soyang and Han River, and the average total mercury in fish was 0.073 ppm, lower than both Korean (0.5 ppm) and EPA criteria (0.3 ppm). However when considering the amount of fish intake for Korean the Hg criterion in fish must be more stringent than current value, and the advisory for fish consumption should be made. Hg in fish considerably varied with sampling sites, having the highest in the upper region (Yang-gu) and the lowest in downstream (Han River). This spatial variation was possibly derived by "bloom dilution" associated with high phosphorus loading or elevated DOC concentrations, or both. Total mercury in sediment varied from 69.9 to $98.3{\mu}g/kg$, which was relatively lower than those measured in Voyageurs National Park in Minnesota in USA ($102{\sim}364{\mu}g/kg$).

• Journal of Korean Society of Environmental Engineers
• /
• v.38 no.8
• /
• pp.435-443
• /
• 2016

In this study, MACT (Maximum Achievable Control Technology) application effect was evaluated for minimization of benzene fugitive emission in petrochemical industry. Although fugitive emission for benzene in the nation was regulated by the Clean Air Conservation Act from 2015, the US EPA already has introduced MACT standard to minimize its emission with up-to-date technology since 1995. EPA Emission Factor (AP-42) and EPA MACT Standard Guideline were used to assess MACT application effect. As a result, For MACT application it could reduce benzene emission up to 98% (average) comparing with uncontrolled facility, while the national regulation could achieve about 95% (average) reduction which is slightly lower than MACT. However there is no control measure in the national regulation to reduce benzene emission for vessel loading even though MACT standard requires preventive facility such as VRU (Vapor Recovery Unit). For further reduction of benzene emission, it needs to be mandatory for operation of VRU when benzene product is loaded in vessel. These efforts could contribute to achieve the global level for benzene emission management in national petrochemical industry.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 1995.10a
• /
• pp.104-107
• /
• 1995

지구온난화에 따른 해면상승이 일어난다면 한국 서해안과 같은 완경사의 간사지의 범람은 크게 일어날 것이다. 향후 2010년 까지의 해면상승에 대한 정량적인 예측에는 불확실성이 있으나 적어도 과거 1세기의 해면상승률 보다는 최소 2배이상일 것으로 추정되고 있다. 또한 IPCC(Inter-governmental Panel on Climate Change)는 각국이 100cm의 go면상승에 대한 영향평가를 수행할 것을 권장하였는데 미국 EPA는 이 보다도 더 비관적인 상승을 추정하고 있다. (중략)

• 수도
• /
• s.66
• /
• pp.90-107
• /
• 1994

일반 정수시설의 설계는 15년 이전경까지는 기성의 기본 Pattern에 따라서 토목기사에 의해서 행해져 왔고 괄목 할만한 변화는 보이지 않았다. 그러나 최근은 살균처리에 따른 부생성물의 발암성에 대한 공포 때문에 미국의 EPA는 음료수의 허용수질의 대폭 개정을 행함과 동시에 살균제, 살균처리의 기준, 발암성이 의심스러운 물질량의 제한, 여과수 탁도의 저감, 급수관의 부식을 방지하기 위한 정수 수질의 조정 등을 공공 수도에 의무화했다. 따라서 이와 같은 조건을 만족시키는 정수처리 계통과 그에 따르는 계장 시설과 정수관리가 필요하며, 화학, 화학 공학, 미생물학, 계장공학 등의 넓은 분야의 전문 지식이 토목 공학에 첨가해서 필요하게 되었다.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 1999.10a
• /
• pp.170-171
• /
• 1999

대기 중 오염물질의 확산 및 미래의 예측을 위하여 대기확산모형을 많이 사용하고 있으며, 국내에서 사용하고 있는 대기확산모형의 대부분은 미국 EPA에서 보급하는 것을 사용하고 있다. 이 중에서 최근에 많이 사용하고 있는 단기모형으로는 기간과 지형이 고려되는 ISCST3 모형을 들 수 있다. 국내 모델의 사용에 있어서 가장 중요한 문제점은 모델의 검정과 보정을 위한 data의 부재를 들 수 있다.(중략)

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 1999.10a
• /
• pp.449-450
• /
• 1999

VOCs(volatile organic compounds)는 대기중에서 질소산화물과 함께 광화학반응에 참여하여 인체 및 동식물에 유해한 오존 등 2차 오염물질인 광화학산화물을 형성하는 전구물질로 작용한다. 1998년 8월 미국 EPA에서는 휘발성유기화합물과 지표 부근의 오존 또는 스모그의 발생량을 감소시키기 위해 페인트, 세제 및 살충제의 제조공법에 관한 새로운 규칙을 발표하여 휘발성 용제 사용 규제를 강호하고 있다(과학기술부, 1998).(중략)

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2000.04a
• /
• pp.259-260
• /
• 2000

알데히드류는 실내 가정의 건축물 단열재, 실내가구의 칠, 접착제, 하드보드, 악취 제거제, 제지 등 생활 용품에서 공업용품에 이르기까지 광범위하게 사용되며, 그 사용량도 증가되고 있다. 특히, formaldehyde는 urea-와 Phenol-formaldehyde 수지를 합성하는 주요 화합물질이다. 알데히드류 중 포름알데히드는 1ppm 또는 그 이하의 농도로 노출될 경우, 눈, 코, 목의 자극을 유발하고, 농도에 따라서 피부 알레르기, 두통, 메스꺼움, 흥부 압박감, 기관지염, 폐염 및 폐부종을 야기하며, 동물 실험결과, 미국 환경보호처에서는 인체 발암 가능성 물질로 분류하고 있다(US EPA, 1999). (중략)