Journal of Ecotechnology Research
Online ISSN : 1884-0388
Print ISSN : 1881-9982
ISSN-L : 1881-9982
Volume 16 , Issue 2
Showing 1-7 articles out of 7 articles from the selected issue
Original Article
  • OSAKA Ken'ichi, HIDA Yoshifumi, KUNIMATSU Takao
    2011 Volume 16 Issue 2 Pages 33-38
    Published: 2011
    Released: March 11, 2015
    JOURNALS FREE ACCESS
     The amount of litter discharge and its influence on nutrient loads from a Japanese cypress plantation watershed were examined. The temporal changes of litter discharge were controlled mainly by the amount of rainfall. The proportions of litter discharge to litterfall of Japanese cypress and Japanese red pine were 0.18?2.11% and 0.03?1.41%, respectively, from 1999 to 2002. The annual nitrogen, phosphorus, and carbon loads from litter discharge in this period were 0.046?0.800, 0.003?0.057, and 1.9?33.0 kg/ha/year, representing 0.6?5.2% and 3.8?10.1% of the total nitrogen and phosphorus loads, respectively. Nutrient loads were highest in 2001, a rainy year, and the contributions of litter discharge to total nutrient loads were also highest in this period. These results show that nutrient loads from litter discharge have a minor influence on total nutrient loads from this forested watershed in normal years, but play an important role in rainy years.
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  • KAWAKAMI Tomonori, S. K. Weragoda, M.A.M.S.L. Attanayake, SAKAMOTO Mas ...
    2011 Volume 16 Issue 2 Pages 39-45
    Published: 2011
    Released: March 11, 2015
    JOURNALS FREE ACCESS
     A massive fish die-off was reported in Kandy Lake, Sri Lanka, in 2009. The maximum number of dead fish was as high as 150 per day. A survey of the water quality of Kandy Lake was conducted in the afternoon on 28 March for the daytime survey and before dawn on 29 March 2010 for the nighttime one. In this research, a hydrographic survey and water sampling at various depths were carried out to determine the cause of the fish die-off. Dissolved Oxygen (DO), nutrients, and heavy metals that could cause a fish die-off were thoroughly analyzed. The lake had sufficient DO to support a fish habitat near the surface layer even in the nighttime. The lake water had high T-N and low T-P concentrations, which could limit the growth of phytoplankton, such as Microcystis. No significant lethality was attributed to heavy metals. No conclusive evidence of the cause of the fish die-off was obtained during the investigation period; however, occasional disturbances could inversely affect a fish habitat. Long-term monitoring of the water quality of Kandy Lake seems to be required.
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  • MANAKA Atsushi, SAWAI Hikaru, TAFU Masamoto, TOSHIMA Takeshi, SURIKAWA ...
    2011 Volume 16 Issue 2 Pages 47-50
    Published: 2011
    Released: March 11, 2015
    JOURNALS FREE ACCESS
     A simple preprocessing method to allow the analysis of the fluoride content of gypsum is proposed for use in gypsum board recycling. The perchloric acid distillation method is well established as a method to quantify the fluoride content of gypsum. However, this method is a long, complex operation using hazardous chemicals. As an alternative, we propose a simple preprocessing method, using cationic and anionic ion exchange resins to allow the analysis of the fluoride content of gypsum using a commercially available kit based on the Lanthanum-Alizarin complexone (La-ALC) method. This preprocessing technique results in greatly increased solubility of calcium sulfate coupled with the separation of fluoride contaminants for quantitative analysis. This makes the determination of fluoride in gypsum by the La-ALC method possible because the preprocessing process does not remove the fluoride ionic species. This method is proposed as a suitable technique for on-site fluoride analysis.
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  • IQBAL Rofiq, INOUE Takanobu
    2011 Volume 16 Issue 2 Pages 51-57
    Published: 2011
    Released: March 11, 2015
    JOURNALS FREE ACCESS
     The aim of this paper is to summarize the studies related to the measurements of mercury pollution in Java Island. It is shown that the main source of mercury pollution was shifted from large-scale industries into small-scale gold minings. It is also found that research activities on mercury pollution in Java are not yet distributed properly. The studies were concentrated in West Java, where Central and East Java Provinces attract less attention from Indonesian researchers. It is also seen that there are increments of mercury concentrations in some areas, such as Kenjeran Beach in Surabaya, Muara Angke of Jakarta Bay and Cibuluh River in the vicinity of Pongkor mining areas. The data also suggested that even though the government succeeded to decrease the number of gold mining operations in one specific area, the miners did not actually stop their operations but just moved to other locations. As for the effects of the mercury pollution to the local population, there is less research that may explain the recent condition in Java. It is highly recommended to monitor mercury concentration in the environment as well as to study the health impact of the mercury to the local inhabitants. It is also advised to have an agreement and coordination between all research institutes in conducting the research to enable the accurate interpretation of the data which will lead to the right conclusion.
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  • TAKAYAMA Katsumi, OKABE Yuta, MATSUI Eiki, KOIZUMI Sadayuki, UEJIMA Ak ...
    2011 Volume 16 Issue 2 Pages 59-63
    Published: 2011
    Released: March 11, 2015
    JOURNALS FREE ACCESS
     Antimony (Sb) is one of the toxic metal pollutants in the environment. The removal technology from toxic metals contaminated soil and water based on bacterial biosorption has many advantages in the high cost performance and diversity compared with well-known physicochemical methods. The screening for Sb-resistant bacteria as bio-adsorbents was performed in 96 surface soils that were collected from a wide variety of locations in Fukui Prefecture, Japan. As a result of this screening, four Sb-resistant bacterial strains were isolated at 37 °C under aerobic conditions in a nutrient medium containing up to 6000 mg/l Sb (as an antimonyl potassium tartrate complex). Detailed analyses of the morphological, biochemical, and 16S rRNA sequence of the most promising candidate among the four strains revealed that it was closely related to Citrobacter murliniae (99.4%). When grown on a nutrient agar plate containing Sb, this strain produced a yellow precipitate, which was concluded to be antimony sulfide, suggesting that the formation of antimony sulfide is an important mechanism of Sb detoxification.
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  • TAFU Masamoto, CHOHJI Tetsuji
    2011 Volume 16 Issue 2 Pages 65-69
    Published: 2011
    Released: March 11, 2015
    JOURNALS FREE ACCESS
     A calcium hydrogen phosphate dihydrate (DCPD) reacts with fluoride ion in a solution to form fluorapatite (FAp). This reaction is very selective and efficient enough. In previous reports, we have appeared that this reaction needs “lag time”. The lag time is induction periods to form “nano-surface structure” on surface of the DCPD particles. Control of the lag time is very important for applying this reaction to fixation of fluoride in the environment. In this paper we assessed effects of reaction temperature and fluoride ion in the aqueous solution on the lag time. Relationship between the lag time and reaction temperature was fit Arrhenius’s equation and activation energy was 84.3 kJ mol-1. We appeared that induction of nano-surface structure” on surface of the DCPD particles is inhibited by fluoride ion in the solution. A “nano-surface DCPD” having nano-surface structure on its surface was easily obtained by mixing with DCPD and water. The obtained “nano-surface DCPD” reacted with fluoride ion in the aqueous solution without the lag time and applicable to removal of fluoride in the environment.
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  • KAWAKAMI Tomonori, MOTOYAMA Ayuri, SERIKAWA Yuka, TAFU Masamoto
    2011 Volume 16 Issue 2 Pages 71-74
    Published: 2011
    Released: March 11, 2015
    JOURNALS FREE ACCESS
     Many residents of the central north province of Sri Lanka such as Anuradhapura region suffer from fluorosis caused by drinking water with high concentration of fluoride. The ground water containing fluoride is supplied as drinking water in the region. The average concentration of fluoride is reported to be 5mg/l which is five times as high as the WHO guideline. In the current research, the removal of fluoride from water by char made from chicken bone was studied. Artificial raw water containing fluoride was contacted with char made from chicken bone and activated carbon to investigate the removal of fluoride. The char made from chicken bone absorbed fluoride efficiently, while activated carbon did not. The absorption of fluoride by char was found as a first order reaction. Assuming a first order reaction, the model calculation showed that 300g of char made from chicken bone is required to purify the contaminated water with a concentration of 10mg/l to less than 1mg/l with a flow rate of 100ml/min. 300g of char can be produced from 600g of chicken bone which is affordable for the Sri Lankan people.
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