IC-MS/MS와 내부표준물질을 이용한 식품 중 perchlorate 분석법 개선

양민준(Minjune Yang),김종성(Jongsung Kim),한종훈(Jonghun Han),허남국(Namguk Her) 한국식품과학회 2011 한국식품과학회지 Vol.43 No.5

본 연구에서는 IC-MS/MS 시스템에 내부표준물질(³⁵Cl¹⁸O4₄)을 이용하여 식품에서의 정확한 perchlorate 분석을 위한 최적화된 전처리 방법을 제시하였다. Perchlorate를 분석하기 위한 식품의 전처리는 미국 FDA에서 제안하는 perchlorate 분석을 위한 식품 전처리 방법을 변형하여 더욱 재현성이 높은 방법을 제시하였으며, 제시된 분석법의 신뢰성을 검증하기 위한 유효성의 검토는 음용수, 우유 및 분유, 쌀, 채소류, 해조류 등 다양한 식품들을 대상으로 MDL과 LOQ를 설정하여 외국의 사례와 비교 확인하였다. 또한 시료에 표준물질을 첨가하여 회수율 및 재현성을 확인하였다. 본 연구에서 수행된 5 μg/L 및 5, 10 μg/kg의 perchlorate 회수율 시험 결과 모든 시료에서 %RSD는 적합범위(<20%) 내에 포함되었고 평균 %RSD는 6.4%로 나타났으며, %Recovery도 98-105%로 적합한(80%<x<120%) 범위로 나타났다. 따라서 본 연구에서 제시한 정확한 perchlorate 분석을 위한 식품 시료의 전처리 방법은 반복 분석을 통한 시험의 정확도 및 재현성을 확인할 수 있었으며, 향후 다른 식품에 대한 perchlorate 분석에도 적용하여 관련분야 연구에 크게 기여할 것으로 기대된다. The internal standard method using ion chromatography combined with tandem mass spectrometry (IC-MS/MS) for quantifying perchlorate in different types of food was established. Because the presence of ions and other biomolecules in matrices usually interrupts accurate determination of perchlorate, it is necessary to develop efficient, reproducible method to determine perchlorate concentrations in food. In this study, the internal standard method was compared with the external standard method to determine perchlorate concentrations in standard samples. The obtained method detection limit (MDL) for perchlorate was 0.005 μg/L for bottled water, 0.12 μg/L for milk, 0.27 μg/kg for rice, 0.16 μg/kg for vegetables, and 0.07 μg/kg for seaweed, respectively. The limit of quantitation (LOQ) was calculated by multiplying the MDL by 7. The recoveries of perchlorate from food samples spiked with perchlorate ranged from 98 to 105% and their percent relative standard deviation (%RSD) levels were <20%. This method was successfully applied for the quantitative determination of perchlorate in various kinds of food.

Autotrophic Perchlorate-Removal Using Elemental Sulfur Granules and Activated Sludge

한경림(Kyoung-Rim Han),강태호(Tae-Ho Kang),강형창(Hyung-Chang Kang),김경현(Kyunghun Kim),서득화(Deuk-Hwa Seo),안영희(Yeonghee Ahn) 한국생명과학회 2011 생명과학회지 Vol.21 No.10

퍼클로레이트(ClO₄)는 지표수 및 토양/지하수에서 검출되는 오염물이다. 미생물은 퍼클로레이트를 무해한 최종산물로 환원시킬 수 있으므로 퍼클로레이트제거는 미생물을 이용한 방법이 가장 적절한 것으로 알려졌다. 미생물이 퍼클로레이트를 환원시키기 위해서는 전자 공여체가 필요하다. 퍼클로레이트를 환원하기 위한 기존의 기술들은 전자 공여체로서 유기물을 사용하는 종속영양방식의 퍼클로레이트환원세균을 사용한다. 그래서 종속영양방식으로 퍼클로레이트를 연속 제거하기 위해서는 지속적으로 유기물을 공급해야 하므로 처리비용이 많이 든다. 본 연구에서는 원소 황 입자와 활성 슬러지를 이용하여 독립영양방식의 퍼클로레이트제거가능성을 조사하였다. 입자상 황은 비교적 값이 저렴하고 활성 슬러지는 하수처리장으로부터 쉽게 구할 수 있는 장점이 있다. 회분배양 실험결과 활성 슬러지 미생물은 전자 공여체로서 황 입자가 존재할 때 퍼클로레이트를 제거할 수 있다는 것이 증명되었다. 이러한 퍼클로레이트 분해는 퍼클로레이트가 분해됨에 따라 생성되는 Cl의 몰 농도를 통해 검증할 수 있었다. 독립영양방식의 ClO₄ 제거공정에 사용된 황 입자의 표면에 간균 형태의 미생물들이 존재한다는 것을 주사전자현미경을 통해 관찰하였다. 그래서 황 입자가 생물막을 형성하기 위한 담체로도 작용할 수 있다는 것을 알 수 있었다. 황입자가 첨가된 ClO₄ 분해성 농화 배양으로부터 채취한 생물막의 미생물군집조성은 접종균으로 사용된 활성 슬러지의 그것과는 다름이 DGGE 분석결과 나타났다. Perchlorate (ClO₄) is a contaminant found in surface water and soil/ground water. Microbial removal of perchlorate is the method of choice since microorganisms can reduce perchlorate into harmless end-products. Such microorganisms require an electron donor to reduce perchlorate. Conventional perchlorate-removal techniques employ heterotrophic perchlorate-reducing bacteria that use organic compounds as electron donors to reduce perchlorate. Since continuous removal of perchlorate requires a continuous supply of organic compounds, heterotrophic perchlorate removal is an expensive process. Feasibility of autotrophic perchlorate-removal using elemental sulfur granules and activated sludge was examined in this study. Granular sulfur is relatively inexpensive and activated sludge is easily available from wastewater treatment plants. Batch tests showed that activated sludge microorganisms could successfully degrade perchlorate in the presence of granular sulfur as an electron donor. Perchlorate biodegradation was confirmed by molar yield of Cl as the perchlorate was degraded. Scanning electron microscope revealed that rod-shaped microorganisms on the surface of sulfur particles were used for the autotrophic perchlorate-removal, suggesting that sulfur particles could serve as supporting media for the formation of biofilm as well. DGGE analyses revealed that microbial profile of the inoculum (activated sludge) was different from that of the biofilm sample obtained from enrichment culture that used sulfur particles for ClO₄-degradation.

Analysis and Exposure Assessment of Perchlorate in Korean Dairy Products with LC-MS/MS

Oh, Sung-Hee,Lee, Ji-Woo,Mandy, Pawlas,Oh, Jeong-Eun The Korean Society of Environmental Toxicology 2011 환경독성보건학회지 Vol.26 No.-

Objectives: Perchlorate is an emerging contaminant that is found everywhere, including various foods. Perchlorate is known to disturb the production of thyroid hormones and leads to mental disorders in fetuses and infants, as well as metabolic problems in adults. In this study, we attempted to establish an LC-MS/MS method for measuring perchlorate in dairy products and used this developed method to investigate perchlorate levels in Korean milk and yogurt samples. Methods: The developed method of perchlorate analysis requires a shaker and 1% acetic acid/acetonitrile as the extracting solvent. Briefly, the samples were extracted and then centrifuged (4000 rpm, 1hour), and the supernatant was then passed through a $Envi^{TM}$ Carb SPE cartridge that had been prewashed sequentially with 6 mL of acetonitrile and 6 mL of 1% acetic acid in water. The final volume of the sample extract was adjusted to 40 mL with reagent water and the final sample was filtered through a 0.20-${\mu}m$ pore size PTFE (Polytetrafluoroethylene) syringe filter prior to LC-MS/MS. Results: The average levels of perchlorate in milk and yogurt samples were $5.63{\pm}3.49\;{\mu}g/L$ and $3.65{\pm}2.42\;{\mu}g/L$, respectively. The perchlorate levels observed in milk samples in this study were similar to those reported from China, Japan, and the United States. Conclusions: The exposure of Koreans to perchlorate through the consumption of dairy products was calculated based on the results of this study. For all age groups, the calculated exposure to perchlorate was below the reference of dose (0.7 ${\mu}g/kg$-day) proposed by the National Academy of Science, USA, but the perchlorate exposure of children was higher than that of adults. Therefore, further investigation of perchlorate in other food samples is needed to enable a more exact assessment of exposure of children to perchlorate.

미생물을 이용한 염수의 퍼클로레이트 제거

안영희(Yeonghee Ahn) 한국생명과학회 2019 생명과학회지 Vol.29 No.11

퍼클로레이트는 물에 용해도가 높고 안정되어 잔류하는 음이온성 오염물이다. 이 오염물은 토양/지하수는 물론 지표수, 먹는물, 식품, 어류, 농작물에도 검출이 되었다. 퍼클로레이트는 갑상선에 요오드가 흡수되는 것을 방해함으로써 대사조절에 중요한 갑상선 호르몬 생산을 감소시키는 것으로 알려졌다. 오염된 환경으로부터 퍼클로레이트를 제거하기 위한 다양한 기술이 개발되었으나 미생물에 의한 생분해가 가장 환경 친화적이고 경제적인 것으로 알려졌다. 그러나 염수와 같은 염이 있는 환경에서의 퍼클로레이트 생분해에 대한 정보는 비교적 제한적이다. 본 논문에서는 미생물을 이용한 염수의 퍼클로레이트 제거와 이와 관련된 미생물에 대해 기술하였다. 대부분 염수의 퍼클로레이트 생분해 연구는 acetate와 같은 유기물을 전자공여체로 사용하는 종속영양방식으로 이루어졌으며 폐재생액(염수) 내의 퍼클로레이트 처리에 중점을 두었다. 폐재생액은 퍼클로레이트로 오염된 지하수를 정화하는데 주로 사용되는 이온교환법에서 발생한다. 내염성 미생물을 농화배양하여 식종한 생물반응기를 통해 최고 10% NaCl 농도에서도 퍼클로레이트의 연속제거가 가능한 것으로 보고되었으나 장기적으로 안정적인 제거는 제시되지 않았다. 염수 내의 퍼클로레이트 제거에 사용된 생물반응기에는 주로 β- 와 γ-Proteobacteria가 우세한 것으로 나타났다. 본 논문에서 기술한 이러한 정보는 생물공학기술 개발을 위해 염수의 퍼클로레이트 생분해에 대한 이해를 하는데 도움을 줄 것이다. Perchlorate is an anionic pollutant that is very soluble and stable in water. It has been detected not only in soil/ground water but also in surface water, drinking water, food, fish, and crops. Perchlorate inhibits iodine uptake by the thyroid gland and reduces production of thyroid hormones that are primarily responsible for regulation of metabolism. Although various technologies have been developed to remove perchlorate from the environment, biodegradation is the method of choice since it is economical and environmentally friendly. However there is limited information on perchlorate biodegradation in salt environment such as salt water. Therefore this paper reviews biodegradation of perchlorate in salt water and related microorganisms. Most biodegradation research has employed heterotrophic perchlorate removal using organic compounds such as acetate as electron donors. Biodegradation research has focused on perchlorate removal from spent brine generated by ion exchange technology that is primarily employed to clean up perchlorate-contaminated ground water. Continuous removal of perchlorate at up to 10% NaCl was shown when bioreactors were inoculated with enriched salt-tolerant perchlorate-reducing bacteria. However the reactors did not show long-term stable removal of perchlorate. Microorganisms belonging to β- and γ-Proteobacteria were dominant in bioreactors used to remove perchlorate from salt water. This review will help our understanding of perchlorate removal from salt water to develop a decent biotechnology for the process.

Analysis and Exposure Assessment of Perchlorate in Korean Dairy Products with LC-MS/MS

오성희,이지우,Pawlas Mandy,오정은 환경독성보건학회 2011 환경독성보건학회지 Vol.26 No.-

Objectives: Perchlorate is an emerging contaminant that is found everywhere, including various foods. Perchlorate is known to disturb the production of thyroid hormones and leads to mental disorders in fetuses and infants, as well as metabolic problems in adults. In this study,we attempted to establish an LC-MS/MS method for measuring perchlorate in dairy products and used this developed method to investigate perchlorate levels in Korean milk and yogurt samples. Methods: The developed method of perchlorate analysis requires a shaker and 1% acetic acid/acetonitrile as the extracting solvent. Briefly,the samples were extracted and then centrifuged (4000 rpm, 1hour), and the supernatant was then passed through a EnviTM Carb SPE cartridge that had been prewashed sequentially with 6 mL of acetonitrile and 6 mL of 1% acetic acid in water. The final volume of the sample extract was adjusted to 40 mL with reagent water and the final sample was filtered through a 0.20-μm pore size PTFE (Polytetrafluoroethylene) syringe filter prior to LC-MS/MS. Results: The average levels of perchlorate in milk and yogurt samples were 5.63 ± 3.49 ㎍/L and 3.65 ± 2.42 ㎍/L, respectively. The perchlorate levels observed in milk samples in this study were similar to those reported from China, Japan, and the United States. Conclusions: The exposure of Koreans to perchlorate through the consumption of dairy products was calculated based on the results of this study. For all age groups, the calculated exposure to perchlorate was below the reference of dose (0.7 ㎍/㎏-day) proposed by the National Academy of Science, USA, but the perchlorate exposure of children was higher than that of adults. Therefore, further investigation of perchlorate in other food samples is needed to enable a more exact assessment of exposure of children to perchlorate.

퍼클로레이트(Perchlorate)의 위해성과 저감기술 소개

신경희(Kyung Hee Shin),손아정(Ah Jeong Son),Daniel K. Cha,김경웅(Kyoung Woong Kim) 大韓環境工學會 2007 대한환경공학회지 Vol.29 No.9

건강유해물질인 perchlorate로 인한 음용수의 오염은 국·내외적으로 심각히 대두되고 있으나, 전세계적으로 perchlorate에 대한국가 차원의 규제 기준을 가진 곳은 아직 없고 발암물질로 구분되지도 않은 상황이다. 최근엔 미국 환경청(US EPA)에서 perchlorate의 예방적 복원 지침서를 발표하였으며, perchlorate 분석 및 저감기술에 관한 연구가 활발히 진행되고 있다. 현재 국내에서는 perchlorate에 대한 먹는 물 수질기준이나 배출 허용 기준 등이 설정되어 있지 않고, perchlorate에 관한 국내 연구는 초기 단계에 머무르고 있다. 본 연구에서는 perchlorate의 성상 및 인체 유해성에 관해 간단히 고찰하였고, 기존의 이온교환(Ion exchange), 생물반응기(Bioreactor), 액상 탄소 흡착(Liquid Phase Carbon Adsorption), 퇴비화 처리(Composting), 현장 생물학적 정화(In Situ Bioremediation), 투수성 반응 벽체(Permeable Reactive Barrier), 식물정화법(Phytotechnology), 막분리기술(Membrane Technologies) 등과 같은 저감 기술의 장단점 및 효율에 관해 소개하였다. 최근 활발히 진행되고 있는 투수성 반응 벽체와 생물학적 환원 기술의 통합 등에 대한 연구 및 분석기술 개발에 대해서도 소개하였다. 본 논문을 통해 향후 국내 실정에 맞는 고효율의 perchlorate 국내저감기술 개발을 위한 기초자료를 제공하고자 하였다. Perchlorate contamination in aquatic system is a growing concern due to the human health and ecological risks associated with perchlorate exposure. In spite of potential risks associated with perchlorate, drinking water standard has not been established worldwide. Recently, US EPA has issued new protective guidance for cleaning up perchlorate contamination with a preliminary clean-up goal of 24.5 ppb. In Korea, the drinking water standard and discharge standard for perchlorate has not been established yet and little information is available to address perchlorate problems. Perchlorate treatment technologies include ion exchange, microbial reactor, carbon adsorption, composting, in situ bioremediation, permeable reactive barrier, phytoremediation, and membrane technology. The process description, capability, and advantages/disadvantages of each technology were described in detail in this review. One of recent trends in perchlorate treatment is the combination of available treatment options such as combined microbial reduction and permeable reactive barrier. In this review, we provided a brief perspective on perchlorate treatment technology and to identify an efficient and cost-effective approach to manage perchlorate problem.

낙동강 수계에서의 Perchlorate 검출 및 활성탄 공정에 의한 제거특성

손희종(Hee Jong Son),정철우(Chul Woo Jung) 大韓環境工學會 2007 대한환경공학회지 Vol.29 No.4

2006년 6월부터 12월까지 낙동강 본류 및 주요 지천들에서의 perchlorate 검출현황을 조사한 결과, 2006년 6월에 구미 하류인 왜관에서 82.1 μg/L가 검출되었으며, 고령에서 34.1 μg/L, 대암 18.3 μg/L, 적포 12.6 μg/L, 남지 13.6 μg/L 및 부산시 상수 취수원인 물금에서 7.6 μg/L가 검출되었다. 이런 결과는 구미와 왜관 사이에 perchlorate 오염원이 존재하는 것을 의미하며, 하류로 갈수록 perchlorate 검출농도가 낮아졌다. 또한, 2006년 7월부터 12월까지 채수한 낙동강 본류 및 지천 시료에서는 perchlorate가 전혀 검출되지 않아 2006년 6월에 일시적으로 perchlorate가 구미와 왜관 사이의 본류에서 유출된 것으로 나타났다. 활성탄 공정에서의 perchlorate 제거 특성을 조사한 결과, 3.1년 사용탄에서는 활성탄 재질별로 거의 흡착능이 없었으며, 석탄계 및 야자계 재질의 활성탄 신탄에서는 운전초기에는 흡착 제거되어지나, 목탄계 활성탄에서는 신탄에서도 제거능이 낮았으며, 석탄계 신탄은 BV 2,300 정도에서 파과에 도달하였고, 야자계와 목탄계 신탄의 파과시점은 BV 719와 288 정도로 나타났다. 또한, 활성탄 g당 perchlorate에 대한 최대 흡착량(X/M)은 석탄계 활성탄이 768.2 μg/g으로 가장 높았으며, 다음으로 야자계 299 μg/g, 목탄계 99.2 μg/g로 나타났다. CUR의 경우 석탄계 활성탄은 0.71 g/일, 야자계와 목탄계 활성탄은 2.16 g/일과 3.45 g/일로 나타났다. 석탄계, 야자계 및 목탄계 활성탄의 k값은 각각 307.2, 102.5 및 94.2로 나타났다. This study was done to investigate perchlorate contamination in Nakdong river. The perchlorate was detected in Nakdong river and ranged from ND to 82.1 μg/L. The highest concentration was observed in Wheguan. The perchlorate concentration was decreased with the down stream of Nakdong river. Three different virgin activated carbons made of each coal(Calgon), coconut(Samchully) and wood(Picabiol) based activated carbon(AC) were tested for an adsorption performance of perchlorate in a continuous adsorption column. Breakthrough behavior was investigated that the breakthrough points of coal, coconut and wood based AC as 2,300 bed volumn(BV), 719 BV and 288 BV respectively. Adsorption capacity(X/M) of coal, coconut and wood based AC was observed. The experimental results of adsorption capacity showed that coal based AC was highest(768.2 μg/g) coconut based AC was intermediate(299 μg/g) and wood based AC was lowest(99.2 μg/g). Moreover, carbon usage rates(CURs) for coal, coconut and wood based AC had been shown as 0.71 g/day, 2.16 g/day and 3.45 g/day respectively. The constant characteristic of the system, k of coal, coconut and wood based ACs were found to be 307.2, 102.5 and 94.2, respectively.

신균주 Rhodococcus sp. YSPW01과 YSPW02를 이용한 수중 내 고농도 Perchlorate 환원 특성 연구

이상훈(Sang Hoon Lee),황재훈(Jae Hoon Hwang),Kabra Akhil,이대성(Dae Sung Lee),전병훈(Byong Hun Jeon) 大韓環境工學會 2014 대한환경공학회지 Vol.36 No.5

수중 내 함유된 고농도 perchlorate의 환원가능성을 perchlorate 환원 미생물인 신균주 Rhodococcus sp. YSPW01과YSPW02로 검토하였다. Perchlorate 환원 미생물은 혐기소화조 슬러지에서 분리 배양하였으며, perchlorate 환원능을 검토하기위해 전자공여체인 acetate를 사용하였다. YSPW01과 YSPW02는 perchlorate 82 mg L-1와 acetate 550 mg L-1에서 회분식 실험을 수행하였을 때, 반응 26시간과 9시간 후 각각 정상상태에 도달하였다. 이 때 perchlorate 환원은 8, 7시간 이내에 초기농도82 mg L-1에서 검출한계 이하(10 μg L-1)까지 제거되었다. 반응조 내에 acetate:perchlorate (w:w)비를 1:1에서 5:1로 증가한결과, perchlorate의 제거 속도는 YSPW01과 YSPW02 모두 2.1, 3.2 mg L-1 h-1에서 15, 15.5 mg L-1 h-1로 약 4.5배 증가하였고,최종 perchlorate는 검출한계 이하까지 제거되었다. 본 연구결과, Rhodococcus sp. YSPW01 및 YSPW02는 고농도 perchlorate제거에 적합하며, 신균주를 고농도 perchlorate 제거를 위한 생물학적 처리공정에 응용가능 할 것으로 판단된다. The feasibility of perchlorate reducing-bacteria isolated from the sludge of an anaerobic digester was determined usingammonium perchlorate in aqueous medium. Growth kinetics of the two perchlorate reducing bacteria including Rhodococcus sp. YSPW01 and YSPW02 were investigated using acetate as the electron donor in batch experiment. The growth of YSPW01 andYSPW02 reached a steady-state at 26 and 9 h, respectively. The initial perchlorate concentration was completely reduced within8 and 7 h by YSPW01 and YSPW02, respectively. The reduction rates were 2.1 and 15 mg L-1 h-1 for YSPW01, and 3.2 and 15.5mg L-1 h-1 for YSPW02, at 1:1 and 5:1 ratios of acetate:perchlorate (w:w), respectively. In this study, the bacteria Rhodococcussp. YSPW01 and YSPW02 demonstrated a potential for the perchlorate reduction, which could be further investigated for developmentof an efficient strategy to treat the perchlorate contaminated waters.

Enhanced Reduction of Perchlorate by Zero-Valent Iron: Effect of Temperature, pH, and Buffering Capacity

Oh, Seok-Young 한국암반공학회 2010 Geosystem engineering Vol.13 No.4

The objective of this study was to enhance the reduction of perchlorate by zero-valent iron (ZVI) to ensure that perchlorate-contaminated water can be significantly treated by employing the iron reduction process. Experiments were designed to accelerate the reduction rate of perchlorate by ZVI by using pH control, alteration of buffering capacity, and elevated temperatures. Batch experiments with pure iron granules demonstrated that chloride was a reduction product of perchlorate at elevated temperature. It was hypothesized that under pH-controlled conditions, perchlorate may be significantly reduced in an iron-packed column at moderately elevated temperatures (< $100^{\circ}C$), i.e. without the need to increase the temperature more than $100^{\circ}C$. The results showed that approximately 60% of perchlorate could be reduced at $75^{\circ}C$ and pH 4.7 with 0.2 M acetate after 120 min. At $99^{\circ}C$ and pH 4.7 with 0.6 M acetate, more than 99% of perchlorate could be removed after 490 min. Most hydrogen ions in the buffer solutions were consumed with short retention times (<120 min), indicating that buffering capacity is critical for enhancing the extent and kinetics of perchlorate reduction in iron-packed columns. However, even without buffering capacity, perchlorate could be completely reduced by ZVI at $150^{\circ}C$ in 5 hrs. Our results suggested that a series of iron-packed columns equipped with heating and buffer-control devices are a viable option for treating perchlorate-laden water continuously at moderately high temperatures (< $100^{\circ}C$). A steam-assisted temperature/ pressurecontrolled batch reactor may be another option for treating perchlorate within a temperature range of 150 to $200^{\circ}C$.

Enhanced Reduction of Perchlorate by Zero-Valent Iron: Effect of Temperature, pH, and Buffering Capacity

오석영 한국자원공학회 2010 Geosystem engineering Vol.13 No.4

The objective of this study was to enhance the reduction of perchlorate by zero-valent iron (ZVI) to ensure that perchlorate-contaminated water can be significantly treated by employing the iron reduction process. Experiments were designed to accelerate the reduction rate of perchlorate by ZVI by using pH control, alteration of buffering capacity, and elevated temperatures. Batch experiments with pure iron granules demonstrated that chloride was a reduction product of perchlorate at elevated temperature. It was hypothesized that under pH-controlled conditions,perchlorate may be significantly reduced in an iron-packed column at moderately elevated temperatures (< 100oC), i.e. without the need to increase the temperature more than 100oC. The results showed that approximately 60% of perchlorate could be reduced at 75oC and pH 4.7 with 0.2 M acetate after 120 min. At 99oC and pH 4.7 with 0.6 M acetate, more than 99% of perchlorate could be removed after 490 min. Most hydrogen ions in the buffer solutions were consumed with short retention times (<120 min), indicating that buffering capacity is critical for enhancing the extent and kinetics of perchlorate reduction in iron-packed columns. However, even without buffering capacity,perchlorate could be completely reduced by ZVI at 150oC in 5 hrs. Our results suggested that a series of iron-packed columns equipped with heating and buffer-control devices are a viable option for treating perchlorate-laden water continuously at moderately high temperatures (< 100oC). A steam-assisted temperature/ pressurecontrolled batch reactor may be another option for treating perchlorate within a temperature range of 150 to 200oC.