Global evaluation of the effects of agriculture and water management adaptations on the water-stressed population

Fresh water is one of the most important resources required for human existence, and ensuring its stable supply is a critical issue for sustainable development. The effects of a general set of agriculture and water management adaptations on the size of the world’s water-stressed population were assessed for a specific but consistent scenario on socio-economic development and climate change during the 21st century. To maintain consistency with agricultural land use change, we developed a grid-based water supply–demand model integrated with an agro-land use model and evaluated the water-stressed population using a water withdrawals-to-availability ratio for river basins. Our evaluation shows that, if no adaptation options are implemented, the world’s water-stressed population will increase from 1.8 billion in 2000 to about 3.3 billion in 2050, and then remain fairly constant. The population and economic growth rather than climate change will be dominant factors of this increase. Significant increase in the water-stressed population will occur in regions such as North Africa and the Middle East, India, Other South Asia, China and Southeast Asia. The key adaptation options differ by region, depending on dominant crops, increase in crop demand and so on. For instance, ‘improvement of irrigation efficiency’ and ‘enhancement of reclamation water’ seem to be one of important options to reduce the water stress in Southeast Asia, and North Africa and the Middle East, respectively. The worldwide implementation of adaptation options could decrease the water-stressed population by about 5 % and 7–17 %, relative to the scenario without adaptations, in 2050 and 2100, respectively.     

Improvement of reporter gene assay for highly sensitive dioxin detection using protoplastic yeast with inactivation of CWP and PDR genes

Environmental Science and Pollution Research - A yeast reporter gene assay system with improved performance for dioxin detection was established. Since yeast reporter gene assays are relatively...     

Risk of Hunger Under Climate Change, Social Disparity, and Agroproductivity Scenarios

Considering the projected population growth in the twenty-first century, some studies have indicated that global warming may have negative impacts on the risk of hunger. These conclusions were derived based on assumptions related to social and technological scenarios that involve substantial and influential uncertainties. In this paper, focusing on agrotechnology and food access disparity, we analyzed food availability and risk of hunger under the combined scenarios of food demands and agroproductivity with and without climate change by 2100 for the B2 scenario in the Special Report on Emissions Scenarios. The results of this study suggest that (1) future food demand can be satisfied globally under all assumed combined scenarios, and (2) a reduction of food access disparity and increased progress in productivity are just as important as climate change mitigation for reducing the risk of hunger.     

Application of rotating cylinder method for ecotoxicological evaluation of antifouling paints

The environmental impact of two biocide-free antifouling paints, fluoropolymer and silicone types, painted on a test cylinder was assessed using a battery of ecotoxicity test and chemical analyses for organic micro-pollutants such as perfluoroalkyl substances (PFAS). A biocide paint containing zinc pyrithione (ZnPT₂) and cuprous oxide was assessed as a positive control. A standardized laboratory rotating-cylinder method using each test cylinder with artificial seawater was performed for 45 days. After 1?h rotation, the leaked seawater was subjected for bioassay and chemical analyses twice weekly. The seawater extracts from the biocide paint showed adverse effects on bacteria, algae, and crustaceans, but those from the biocide-free paints did not. The leakage seawater from biocide-free paints, after 7-day continuous rotation, contained the same concentration levels of PFAS as blank seawater used to conduct the tests. Thus, no significant toxicities of the biocide-free paints were found under the conditions of this study. Simultaneous analysis of ZnPT₂ and copper pyrithione (CuPT₂) was developed using an HPLC with a polymeric resin column, showing that ZnPT₂ was converted to CuPT₂ by trans-chelation in the leakage seawater from the positive control paint. The experimental results using a laboratory rotating-cylinder method demonstrated that biocide-free paints did not markedly affect three species tested and no PFAS was detected. In contrast, biocide paint was significantly toxic to test species and toxicity of the extract on bacteria was partly responsible for CuPT₂ produced in leakage seawater. Thus, a laboratory rotating-cylinder method may be applied for ecotoxicological assessment of antifouling paints.     

Photodecomposition of humic acid and natural organic matter in swamp water using a TiO2-coated ceramic foam filter: Potential for the formation of disinfection byproducts

This paper reports on the photodecomposition of aqueous humic acid (HA) by a TiO₂-coated ceramic foam filter (TCF) reactor and on the potential for the formation of disinfection byproducts (DBPs) upon chlorination of the photocatalytically treated solutions. This photocatalytic reactor can also be applied to the removal of natural organic matter (NOM) in swamp waters. The proposed photocatalytic reaction system was operated as per standardized methodologies. First, the ability of the TCF to decompose HA (a representative compound of NOM) was evaluated from the changes in the total organic carbon (TOC) and UV₂₅₄ with the reaction time. Remarkably, TOC removal and UV₂₅₄ values ranging from 44% to 61% and from 60% to 83%, respectively, were achieved. The potential for the formation of DBPs (total trihalomethane and total haloacetic acid) by chlorination of the phototreated solution was strongly dependent on the TOC removal and UV₂₅₄ values in the solution. The degree of photodecomposition of NOMs in the swamp water samples and the DBP formation potential showed similar trends as in the case of the standard solutions containing HA. The method used in this study could be effectively used to evaluate the efficiency of TCF for reducing HA and NOM, while suppressing the formation of DBP products.     

Effect of 17beta-estradiol on the reproduction of Japanese medaka (Oryzias latipes)

Estrogenic compounds such as 17beta-estradiol (E2) and its analogs are present in the aquatic environment and can adversely affect the reproductive systems of aquatic organisms. Although E2 has been detected at a maximum concentration of 64 ng/l in effluents of sewage treatment works (STWs), few reports address the associated effects on reproduction in fish. Therefore, we exposed adult medaka (Oryzias latipes) to mean measured E2 concentrations of 29.3, 55.7, 116, 227, and 463 ng/l for 21 d and assessed the effects on the egg number and fertility of paired medaka during the exposure period. In addition, we determined the hepatic vitellogenin (Vtg) concentration and histologically assessed the gonads of these fish. The number of egg produced and fertility of the paired medaka exposed to 463 ng/l E2 were significantly less compared with those of the control fish. Males in all treatment groups had developed testis-ova. Males treated with E2 concentrations = 55.7 ng/l contained relating great concentrations of hepatic Vtg. Therefore, although only the greatest E2 concentration tested in our study affected fecundity and fertility, effects of E2 were observed on induction of Vtg and testis-ova in male medaka exposed to environmentally relevant concentrations of E2.     

Production and characterization of KOH-activated carbon derived from polychlorinated biphenyl residue generated by the sodium dispersion process

Polychlorinated biphenyl (PCB) residues from the sodium dispersion (SD) process were employed as the raw materials for the production of activated carbon using KOH activation. The pore properties, such as the specific surface area and pore size distribution, were characterized using the Barrett–Joyner–Halenda method and the Horvath–Kawazoe method based on the N₂ adsorption isotherm at 77 K. The activated carbon produced showed similar adsorption capacities and specific surface areas to the commercially available product. The effects of the activation conditions on the porosity of the activated carbon produced were studied. The most significant factor affecting the specific surface proved to be the activation temperature. The activated carbon produced from PCB residues from the high-temperature (423–443 K) SD process had a binary pore size distribution well developed in the 4 nm region and in the micropore region. The pore structure of the carbon produced from PCB residues from the low-temperature (333–393 K) SD process had a wide range of micropores and mesopores.     

排列法检测围隔生态实验中加磷对浮游植物结构的影响

分析了1997和1998年3次围隔实验中的浮游生物结构和环境因子，检验加P及赤潮前后的变化和对它们的影响。采用因子分析（EA）和关联分析（CA），得出浮游植物种类集合的序列，根据因子分析和关 联分析的前两个轴建立平面坐标，并用方差分析（ANOVA）检验其差异，探讨加P及赤潮相关的群落结构模式。建立种类序列坐标轴，为确定种对结构分散的重要程度评估提供 客观方法，并用方差检验差异确立加P发生赤潮和 分浮游植物的体积进行了测量，并用经验公式计算了单个细胞的碳含量。     

Identification and detection sensitivity of <Emphasis Type="Italic">Microcystis aeruginosa</Emphasis> from mixed and field samples using MALDI-TOF MS

To verify the applicability of identifying Microcystis aeruginosa by matrix-assisted laser desorption-ionization-time-of-flight mass spectrometry (MALDI-TOF MS), mixed and field samples were employed to study the sensitivity and the analysis power, respectively. Series diluted samples and artificially mixed samples by the M. aeruginosa NIES-843 strain were designed to verify the sensitivity. The lowest detection limit was 1.955?×?10⁶ cells in pure samples, while for mixed samples, the lowest detection limit and ratio of NIES-843 strain were 2.88?×?10⁶ cells and 33.7%, respectively. The results provided a reference for the reasonable volume of the water sample in which the M. aeruginosa could be detected. Ribosomal protein biomarkers for identifying M. aeruginosa which were successfully detected from the field samples in Taihu Lake, indicated that the identification of M. aeruginosa by MALDI-TOF MS could be applied in field samples. Furthermore, different genetic types of M. aeruginosa strains were also detected at different locations in Taihu Lake, which revealed the diversity of M. aeruginosa and the detection power of MALDI-TOF MS at the strain level for the field samples. The sensitivity and detection power in the analysis of M. aeruginosa by the MALDI-TOF MS demonstrated the applicability of this method in routine environmental monitoring.