We evaluate the suitability of a fly-ash-shell blocks (FSBs) for periphytic diatom growth. FSBs and concrete and granite blocks (length 4 cm, width 16 cm, and height 4 cm) were immersed in an aquarium filled with sea water for two weeks. The upper surfaces of the blocks were photographed by digital cameras every weekday. The increase of the periphytic diatom biomass (Chl-a) on the blocks with time was understood from image analysis using a color channel having a high correlation with Chl-a. Factors defining the growth characteristics, such as specific growth rate in the exponential phase and initial recruitment rate, were obtained from the temporal change in the biomass, and were compared among each type of material of the blocks. The results, show that while the diatom recruitment rate was fastest on concrete, the specific growth rate in the exponential phase showed no difference among the materials.
{"title":"Verification of Suitability of Fly-Ash-Shell Blocks for Algal Growth: Understanding Growth Characteristics of Periphytic Diatoms by Using Non-Distractive Measurement Method","authors":"M. Honda, M. Imamura, Takuya Kobayashi, Y. Hiei","doi":"10.2965/jswe.43.79","DOIUrl":"https://doi.org/10.2965/jswe.43.79","url":null,"abstract":"We evaluate the suitability of a fly-ash-shell blocks (FSBs) for periphytic diatom growth. FSBs and concrete and granite blocks (length 4 cm, width 16 cm, and height 4 cm) were immersed in an aquarium filled with sea water for two weeks. The upper surfaces of the blocks were photographed by digital cameras every weekday. The increase of the periphytic diatom biomass (Chl-a) on the blocks with time was understood from image analysis using a color channel having a high correlation with Chl-a. Factors defining the growth characteristics, such as specific growth rate in the exponential phase and initial recruitment rate, were obtained from the temporal change in the biomass, and were compared among each type of material of the blocks. The results, show that while the diatom recruitment rate was fastest on concrete, the specific growth rate in the exponential phase showed no difference among the materials.","PeriodicalId":16300,"journal":{"name":"Journal of Japan Society on Water Environment","volume":"107 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77417837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effects of operations to increase nitrogen discharge from sewage treatment plants to prevent oligotrophication at Harima-nada in the Seto Inland Sea on concentrations of organic matter, nitrogen, and phosphorus in surface water were evaluated. First, the sea waters around the Futami treatment center, which has been conducting the operation, were analyzed. The results show that no significant changes in water quality were observed during the operation. Next, the effects of the operations of 20 sewage treatment plants at Harima-nada on the water quality were simulated using a numerical simulation model. As a result, it was estimated that dissolved inorganic nitrogen and phosphorus were taken up by phytoplankton, and organic matter and nitrogen concentrations in the entire area of Harima-nada were increased by phytoplankton advection and diffusion. The observed values could not confirm the effect of the operation to increase nitrogen discharge at the Futami treatment center owing to dilution by seawater and the drainages of other nitrogen emission sources. However, it was shown that when the number of operations to increase nitrogen discharge from sewage treatment plants increased, the water quality in a wide area of Harima-nada may be affected.
{"title":"Evaluating the Effects of Operations to Increase Nitrogen Discharge from Sewage Treatment Plants on Concentrations of Organic Matter and Nutrients in Surface Water at Harima-nada in the Seto Inland Sea","authors":"Motoharu Suzuki, Yusuke Nakatani, Yutaro Koga","doi":"10.2965/jswe.43.43","DOIUrl":"https://doi.org/10.2965/jswe.43.43","url":null,"abstract":"The effects of operations to increase nitrogen discharge from sewage treatment plants to prevent oligotrophication at Harima-nada in the Seto Inland Sea on concentrations of organic matter, nitrogen, and phosphorus in surface water were evaluated. First, the sea waters around the Futami treatment center, which has been conducting the operation, were analyzed. The results show that no significant changes in water quality were observed during the operation. Next, the effects of the operations of 20 sewage treatment plants at Harima-nada on the water quality were simulated using a numerical simulation model. As a result, it was estimated that dissolved inorganic nitrogen and phosphorus were taken up by phytoplankton, and organic matter and nitrogen concentrations in the entire area of Harima-nada were increased by phytoplankton advection and diffusion. The observed values could not confirm the effect of the operation to increase nitrogen discharge at the Futami treatment center owing to dilution by seawater and the drainages of other nitrogen emission sources. However, it was shown that when the number of operations to increase nitrogen discharge from sewage treatment plants increased, the water quality in a wide area of Harima-nada may be affected.","PeriodicalId":16300,"journal":{"name":"Journal of Japan Society on Water Environment","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83696331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Morio Tsuji, Yutaro Nagasawa, H. Itoh, Masaki Suzuki
The influence of different land use types on groundwater was evaluated on the basis of the relationship between the annual water quality fluctuation and the content of stable NO3 isotopes in winter in five spring water samples collected from a river terrace. The compositions of two spring water samples from the edge of the terrace with forested land use on the upstream side were very similar and were not affected by anthropogenic activity. Spring water collected from the terrace surface near a paddy field was influenced by ammonium sulfate, but contained low concentrations of NO3-N. The quality of spring water from a terrace site surrounded by agricultural land (a vegetable field) suggested the influence of chemical fertilizers, such as magnesian lime and ammonium chloride. In spring water from a terrace site where a poultry farming facility and residential area were located, the concentration of N derived from organic matter and the K, Na, and Cl ion contents were high. This pollution from domestic drainage is a cause of concern.
{"title":"Relationship between Spring Water Quality and Land Use Type in a Small Area","authors":"Morio Tsuji, Yutaro Nagasawa, H. Itoh, Masaki Suzuki","doi":"10.2965/jswe.43.55","DOIUrl":"https://doi.org/10.2965/jswe.43.55","url":null,"abstract":"The influence of different land use types on groundwater was evaluated on the basis of the relationship between the annual water quality fluctuation and the content of stable NO3 isotopes in winter in five spring water samples collected from a river terrace. The compositions of two spring water samples from the edge of the terrace with forested land use on the upstream side were very similar and were not affected by anthropogenic activity. Spring water collected from the terrace surface near a paddy field was influenced by ammonium sulfate, but contained low concentrations of NO3-N. The quality of spring water from a terrace site surrounded by agricultural land (a vegetable field) suggested the influence of chemical fertilizers, such as magnesian lime and ammonium chloride. In spring water from a terrace site where a poultry farming facility and residential area were located, the concentration of N derived from organic matter and the K, Na, and Cl ion contents were high. This pollution from domestic drainage is a cause of concern.","PeriodicalId":16300,"journal":{"name":"Journal of Japan Society on Water Environment","volume":"160 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76573178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sayoko Oba, Kouki Kirihara, Masaki Otsuchihashi, H. Takanashi, T. Nakajima, T. Ueda, J. Kadokawa, H. Ishikawa, N. Miyamoto
There are some reports that transformation products of a pesticide exist at higher concentrations than their parent pesticide, or their pharmacological activities are comparable to that of a parent pesticide. It is therefore of importance to examine their potential effects on aquatic organisms; however, few studies have focused on the insecticidal activities of a transformation product of dinotefuran, a neonicotinoid pesticide. In this study, dinotefuran’s transformation products were explored by LC-HRMS analyses of dinotefuran aqueous solutions that had been irradiated by a xenon lamp. This exploration resulted in the discovery of two unknown transformation products. Structural elucidations of these two compounds suggested 28 and 82 chemical structures in terms of structural isomers and steric isomers, respectively. Their binding affinities for a glia-derived acetylcholine-binding protein of Lymnaea stagnalis were simulated to estimate their insecticidal activities. Out of 28 candidates, 20 were judged to have significant insecticidal activities. It can be concluded that the simulation of a substance’s binding affinity, the so-called docking simulation, is a promising way to exclude nontoxic substances among a large number of candidate substances.
{"title":"Binding Affinity Evaluation of Monohydroxydinotefuran and Its Isomers to Acetylcholine Receptor","authors":"Sayoko Oba, Kouki Kirihara, Masaki Otsuchihashi, H. Takanashi, T. Nakajima, T. Ueda, J. Kadokawa, H. Ishikawa, N. Miyamoto","doi":"10.2965/jswe.43.1","DOIUrl":"https://doi.org/10.2965/jswe.43.1","url":null,"abstract":"There are some reports that transformation products of a pesticide exist at higher concentrations than their parent pesticide, or their pharmacological activities are comparable to that of a parent pesticide. It is therefore of importance to examine their potential effects on aquatic organisms; however, few studies have focused on the insecticidal activities of a transformation product of dinotefuran, a neonicotinoid pesticide. In this study, dinotefuran’s transformation products were explored by LC-HRMS analyses of dinotefuran aqueous solutions that had been irradiated by a xenon lamp. This exploration resulted in the discovery of two unknown transformation products. Structural elucidations of these two compounds suggested 28 and 82 chemical structures in terms of structural isomers and steric isomers, respectively. Their binding affinities for a glia-derived acetylcholine-binding protein of Lymnaea stagnalis were simulated to estimate their insecticidal activities. Out of 28 candidates, 20 were judged to have significant insecticidal activities. It can be concluded that the simulation of a substance’s binding affinity, the so-called docking simulation, is a promising way to exclude nontoxic substances among a large number of candidate substances.","PeriodicalId":16300,"journal":{"name":"Journal of Japan Society on Water Environment","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87467403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Hiraoka, Yuhei Omich, S. Nakahara, T. Ikeda, M. Okada
The objective of this study is to clarify the effects of typhoon 0418 on the macrobenthic community in the tidal flats on the coast of Iwakuni in Hiroshima Bay, using monitoring data from 2001 to 2016. Zostera beds disappeared after typhoon 0418 hit in September 2004. The distribution area of the beds recovered to the pretyphoon level after more than eight years, because of two consecutive years of disturbance by typhoons. The bottom sediment of the tidal flats showed large fluctuations in the mud content, COD （ Chemical Oxygen Demand ） and IL （ Ignition Loss ） regardless of changes in the Zostera bed area. Macrobenthic communities showed a drastic decrease in number of species, number of individuals, wet weight and diversity （ H’ ） after typhoon 0418. These values were low during the deterioration period （ from just after typhoon 0418 to 2008 ） of Zostera beds, but became high during the recovery period （ 2009 and later ） . These results show that the presence of Zostera beds is important to the macrobenthic community in tidal flats and that typhoon 0418 had both short- and long-term effects on the macrobenthic community in the tidal flats as it caused physical disturbance and subsequent loss of Zostera beds.
{"title":"Short- and Long-term Effects of Typhoon 0418 on Macrobenthic Community in Tidal Flats on the Coast of Iwakuni in Hiroshima Bay","authors":"K. Hiraoka, Yuhei Omich, S. Nakahara, T. Ikeda, M. Okada","doi":"10.2965/jswe.43.97","DOIUrl":"https://doi.org/10.2965/jswe.43.97","url":null,"abstract":"The objective of this study is to clarify the effects of typhoon 0418 on the macrobenthic community in the tidal flats on the coast of Iwakuni in Hiroshima Bay, using monitoring data from 2001 to 2016. Zostera beds disappeared after typhoon 0418 hit in September 2004. The distribution area of the beds recovered to the pretyphoon level after more than eight years, because of two consecutive years of disturbance by typhoons. The bottom sediment of the tidal flats showed large fluctuations in the mud content, COD （ Chemical Oxygen Demand ） and IL （ Ignition Loss ） regardless of changes in the Zostera bed area. Macrobenthic communities showed a drastic decrease in number of species, number of individuals, wet weight and diversity （ H’ ） after typhoon 0418. These values were low during the deterioration period （ from just after typhoon 0418 to 2008 ） of Zostera beds, but became high during the recovery period （ 2009 and later ） . These results show that the presence of Zostera beds is important to the macrobenthic community in tidal flats and that typhoon 0418 had both short- and long-term effects on the macrobenthic community in the tidal flats as it caused physical disturbance and subsequent loss of Zostera beds.","PeriodicalId":16300,"journal":{"name":"Journal of Japan Society on Water Environment","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79023794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
一弘 小松, 秀美 尾内, 章雄 今井, 伸之 川崎, Hashim Emi Fazlina, Rajuddin Mohd Kushairi Mohd
{"title":"土壌抽出物中溶存有機物 (DOM) の微細藻類増殖に及ぼす影響","authors":"一弘 小松, 秀美 尾内, 章雄 今井, 伸之 川崎, Hashim Emi Fazlina, Rajuddin Mohd Kushairi Mohd","doi":"10.2965/JSWE.42.239","DOIUrl":"https://doi.org/10.2965/JSWE.42.239","url":null,"abstract":"","PeriodicalId":16300,"journal":{"name":"Journal of Japan Society on Water Environment","volume":"2 1","pages":"239-246"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72932298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The contribution of dissolved organic carbon （ DOC ） decomposition to oxygen consumption was estimated in the inner part of the Ariake sea. Oxygen consumption and decomposition of particulate organic carbon （ POC ） and DOC were estimated using the bottom water samples collected from two stations in the inner part of the Ariake sea from May to August 2018. The contribution of DOC decomposition to total organic carbon decomposition was about 10%. Although the contribution of organic matter decomposition to total oxygen consumption was 47.0-54.2% before the occurrence of hypoxia, the contribution of organic matter decomposition to total oxygen consumption was minor during the hypoxia. These results suggest that organic matter decomposition plays an important role in oxygen consumption before the occurrence of hypoxia, and DOC decomposition is one of the driving forces of hypoxia.
{"title":"Contribution of Organic Matter Decomposition in Water Column to Oxygen Consumption in the Inner Part of the Ariake Sea","authors":"K. Uchino, Haruka Inomata, Saki Tahara, H. Takasu","doi":"10.2965/jswe.42.195","DOIUrl":"https://doi.org/10.2965/jswe.42.195","url":null,"abstract":"The contribution of dissolved organic carbon （ DOC ） decomposition to oxygen consumption was estimated in the inner part of the Ariake sea. Oxygen consumption and decomposition of particulate organic carbon （ POC ） and DOC were estimated using the bottom water samples collected from two stations in the inner part of the Ariake sea from May to August 2018. The contribution of DOC decomposition to total organic carbon decomposition was about 10%. Although the contribution of organic matter decomposition to total oxygen consumption was 47.0-54.2% before the occurrence of hypoxia, the contribution of organic matter decomposition to total oxygen consumption was minor during the hypoxia. These results suggest that organic matter decomposition plays an important role in oxygen consumption before the occurrence of hypoxia, and DOC decomposition is one of the driving forces of hypoxia.","PeriodicalId":16300,"journal":{"name":"Journal of Japan Society on Water Environment","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79410800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Sugimoto, Takanori Sugano, Shigemori Takahama, Hikaru Takashima, Yoichi Takata, M. Okada
The purpose of this study is to investigate the formation of seaweed bed substrata using different sizes of Ferromanganese slag and Ferromanganese slag block in the sea area and by comparing them with the surrounding natural seaweed bed. We were unable to confirm any changes in pH or manganese concentration in seawater as a result of using FMS and FMSB. Small seaweed such as Hypnea grew five months after the material was set up. After 17 months, Sargassum horneri , Myagropsis myagroides , Undaria pinnatifida , and Ecklonia kurome grew on FMS, whereas S . horneri , Sargassum piluliferum , and Ecklonia kurome grew on FMSB. The vegetation transition progressed from undergrowth seaweed to large seaweed. About one year after the installation of the FMS and FMSB substrata, there was no significant difference in the number of seaweed species that grew on FMS and FMSB and the nearby natural seaweed bed. However, there was a small difference in the seaweed biomass between the FMS （ 30-75 mm ） and the surrounding natural seaweed bed. We found that when using smaller material, FMS （ 30-75 mm ） has higher seaweed biomass except in November 2017. By installing FMS and FMSB seaweed beds, we were able to confirm that the gathering fish are similar to those that gather around the nearby natural seaweed bed, but we were unable to confirm the relationship between seaweed biomass, material size, and fish density.
{"title":"Application of Ferromanganese Slag of Different Sizes as Seaweed Bed Substratum","authors":"K. Sugimoto, Takanori Sugano, Shigemori Takahama, Hikaru Takashima, Yoichi Takata, M. Okada","doi":"10.2965/JSWE.42.123","DOIUrl":"https://doi.org/10.2965/JSWE.42.123","url":null,"abstract":"The purpose of this study is to investigate the formation of seaweed bed substrata using different sizes of Ferromanganese slag and Ferromanganese slag block in the sea area and by comparing them with the surrounding natural seaweed bed. We were unable to confirm any changes in pH or manganese concentration in seawater as a result of using FMS and FMSB. Small seaweed such as Hypnea grew five months after the material was set up. After 17 months, Sargassum horneri , Myagropsis myagroides , Undaria pinnatifida , and Ecklonia kurome grew on FMS, whereas S . horneri , Sargassum piluliferum , and Ecklonia kurome grew on FMSB. The vegetation transition progressed from undergrowth seaweed to large seaweed. About one year after the installation of the FMS and FMSB substrata, there was no significant difference in the number of seaweed species that grew on FMS and FMSB and the nearby natural seaweed bed. However, there was a small difference in the seaweed biomass between the FMS （ 30-75 mm ） and the surrounding natural seaweed bed. We found that when using smaller material, FMS （ 30-75 mm ） has higher seaweed biomass except in November 2017. By installing FMS and FMSB seaweed beds, we were able to confirm that the gathering fish are similar to those that gather around the nearby natural seaweed bed, but we were unable to confirm the relationship between seaweed biomass, material size, and fish density.","PeriodicalId":16300,"journal":{"name":"Journal of Japan Society on Water Environment","volume":"113 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76986832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For phosphorus recovery, we used the technique of bacterial leaching to elute phosphorus from night soil sludge incineration ash using sulfur-oxidizing bacteria. The purpose of this study was to obtain practically enriched strains of bacteria suitable for the local environment without a complicated isolation operation and to confirm a simple and economical medium composition. Three bacterial strains were enriched at night soil treatment facilities by using the medium for sulfur-oxidizing bacteria. Two enriched strains had a greater ability to generate sulfuric acid and elute phosphorus than Acidithiobacillus thiooxidans NBRC13701 （ NBRC ） which was used for comparison. Clone library analysis indicated that seven and five kinds of Acidithiobacillus spp. strain were included in these enriched strains, respectively. The ability of another enriched strain for sulfuric acid generation and phosphorus elution did not reach that of NBRC, but it was thought that this enriched strain included only A. caldus with a higher optimal growth temperature than those of the others. With regard to the medium composition, seven of the 11 original components could be omitted. For sulfur, an important substrate, inexpensive desulfurization sulfur could be used. The ability of sulfuric acid generation was unaffected by these changes, but the medium preparation cost was reduced to 1/18.
{"title":"Practical Enrichment of Strains of Sulfur-oxidizing Bacteria and Economical Medium for Bacterial Leaching","authors":"Yousuke Nakamura, M. Otsuka, S. Haruta, D. Omori","doi":"10.2965/JSWE.42.145","DOIUrl":"https://doi.org/10.2965/JSWE.42.145","url":null,"abstract":"For phosphorus recovery, we used the technique of bacterial leaching to elute phosphorus from night soil sludge incineration ash using sulfur-oxidizing bacteria. The purpose of this study was to obtain practically enriched strains of bacteria suitable for the local environment without a complicated isolation operation and to confirm a simple and economical medium composition. Three bacterial strains were enriched at night soil treatment facilities by using the medium for sulfur-oxidizing bacteria. Two enriched strains had a greater ability to generate sulfuric acid and elute phosphorus than Acidithiobacillus thiooxidans NBRC13701 （ NBRC ） which was used for comparison. Clone library analysis indicated that seven and five kinds of Acidithiobacillus spp. strain were included in these enriched strains, respectively. The ability of another enriched strain for sulfuric acid generation and phosphorus elution did not reach that of NBRC, but it was thought that this enriched strain included only A. caldus with a higher optimal growth temperature than those of the others. With regard to the medium composition, seven of the 11 original components could be omitted. For sulfur, an important substrate, inexpensive desulfurization sulfur could be used. The ability of sulfuric acid generation was unaffected by these changes, but the medium preparation cost was reduced to 1/18.","PeriodicalId":16300,"journal":{"name":"Journal of Japan Society on Water Environment","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79534759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Hayakawa, Y. Hirose, T. Okamoto, Syo-ichi Hichiri, T. Ohara, Kiyuki Noto, Shinsuke Inoue
Total organic carbon (TOC) is one of the indicators of organic pollution in aquatic environments. In this study, the pretreatment and measurement procedures employed when using a TOC analyzer with combustion catalytic oxidation are investigated to improve the accuracy of the analysis for samples containing suspended particles. Our results show that ultrasonically disrupting the particles promotes the homogenization of the suspension, which improves the accuracy of the TOC measurement. The TOC analyzer, which was designed to reduce the loss of samples in the injection syringe and the pathway of the equipment, obtained good recovery rates for samples taken from the north basin of Lake Biwa. However, low recovery rates were obtained for samples with high concentrations of suspended solids or dissolved organic matter. The low recovery rates reduced the accuracy of particulate organic carbon (POC) concentrations calculated as the difference between TOC and dissolved organic carbon (DOC) concentrations. It was found that the accuracy can be improved by using different methods (NPOC and TC-IC methods) for TOC combustion oxidation, depending on the sample concentration.
{"title":"Modification of Analytical Procedure for Determining Total Organic Carbon in Lake Waters Using a TOC Analyzer","authors":"K. Hayakawa, Y. Hirose, T. Okamoto, Syo-ichi Hichiri, T. Ohara, Kiyuki Noto, Shinsuke Inoue","doi":"10.2965/jswe.42.259","DOIUrl":"https://doi.org/10.2965/jswe.42.259","url":null,"abstract":"Total organic carbon (TOC) is one of the indicators of organic pollution in aquatic environments. In this study, the pretreatment and measurement procedures employed when using a TOC analyzer with combustion catalytic oxidation are investigated to improve the accuracy of the analysis for samples containing suspended particles. Our results show that ultrasonically disrupting the particles promotes the homogenization of the suspension, which improves the accuracy of the TOC measurement. The TOC analyzer, which was designed to reduce the loss of samples in the injection syringe and the pathway of the equipment, obtained good recovery rates for samples taken from the north basin of Lake Biwa. However, low recovery rates were obtained for samples with high concentrations of suspended solids or dissolved organic matter. The low recovery rates reduced the accuracy of particulate organic carbon (POC) concentrations calculated as the difference between TOC and dissolved organic carbon (DOC) concentrations. It was found that the accuracy can be improved by using different methods (NPOC and TC-IC methods) for TOC combustion oxidation, depending on the sample concentration.","PeriodicalId":16300,"journal":{"name":"Journal of Japan Society on Water Environment","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73364496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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