Salt and Seawater Science & Technology
Online ISSN : 2435-4619
  • Shinnosuke KAMEI, Masakazu MATSUMOTO
    2024 年 5 巻 p. 1-7
    発行日: 2024年
    公開日: 2024/04/03
    ジャーナル フリー
    Synthesis method of inorganic compounds from seawater or raw materials originating from seawater and its characterization were reviewed. The inorganic compounds to be introduced are Layerd double hydrate (LDH), Northpite (Na3Mg(CO3)2Cl), Calcium carbonate (CaCO3) and protodolomite and Dolomite (CaMg(CO3)2). The effects of the synthetic conditions on the products and the functionality of these materials are described. Therefore, the useful material production form seawater is important to continue preventing poor resource for Japan. Here's a brief description of the details.
  • Kiyomi TAKASE, Izuru KAKUTA
    2024 年 5 巻 p. 8-16
    発行日: 2024年
    公開日: 2024/04/13
    ジャーナル フリー
    Neonicotinoid insecticides (NEOs) are widely used in many agricultural products. However, it has been pointed out that it may flow into rivers, lakes, and coastal areas and affect organisms inhabiting those environments. In this study, the effects of exposure to NEOs at concentrations and exposure periods observed in rivers, waterways and agricultural drainage channels around rice paddies, where Japanese killifish (Oryzias latipes) inhabit, on their anxiety behavior were assessed by light/dark preference tests. We also examined whether or not the anxiety behavior recovered when reared in clean water after exposure to NEOs. Japanese killifish were divided into seven groups of seven males and females each as follows and reared for one week: pesticide-free (Control), thiamethoxam (THM) exposure; 10 and 200 μg/L, dinotefuran (DIN) exposure; 6 and 120 μg/L, fipronil (FIP) exposure; 1 and 20 μg/L. Light/dark preference tests were conducted immediately before exposure, one day and one week after exposure to measure the percentage of time spent on a black background (Choice index) and the number of times the fish moved between the black and white demarcation line. After the oneweek exposure test, the Japanese killifish were again subjected to the light/dark preference test after two weeks in clean water to determine any behavioral changes. Before pesticide exposure, Japanese killifish spent most of the time in the dark, but one and seven days after exposure to low and high concentrations of THM and DIN, their dark selectivity was significantly lower than that of the control group. Similar changes were also observed in individuals exposed to FIPs. Furthermore, when the killifish were returned to clean water seven days after exposure and kept for at least two weeks, dark selectivity increased (recovered) again in the FIP-exposed group, whereas dark selectivity did not recover in both sexes in the groups exposed to THMs and DINs. In other words, the effects of NEOs exposure are irreversible or long-lasting, and once exposed, even if the animals return to clean water afterwards, the effects will continue for a long period of time for aquatic organisms, and there is concern about the effects on the ecosystem.
  • Takaaki WAJIMA, Ryoto HASHIKAWA
    2024 年 5 巻 p. 18-19
    発行日: 2024年
    公開日: 2024/04/16
    ジャーナル フリー
    Adsorption of PGMs, Rh, Ir, and Ru, on sulfur-impregnated charcoal, which is prepared from domestic biomass resource, bamboo, via pyrolysis after sulfur-immersion, was examined to apply for PGMs recovery from wastewater. Sulfur-impregnated bamboo charcoal can adsorb Ir and Ru, indicating higher adsorption capacity for Ir (12.2 mg/g) and Ru (15.9 mg/g) than commercial activated carbon, while Rh can't be adsorbed.