著者

Yifan Zhu Wakana Oishi Mayuko Saito Masaaki Kitajima Daisuke Sano

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.19, no.3, pp.170-183, 2021 (Released:2021-06-10)

参考文献数

60

被引用文献数

10

---

Amid the ongoing battle against COVID-19, the scientific community has high hope in wastewater-based epidemiology (WBE). It was not only proposed as a complement to capacity-plagued clinical testing, but also an early warning tool that may enable timely intervention measures. In this study, we developed a wastewater SARS-CoV-2 RNA load model based on the fecal shedding profile of infected individuals. The epidemic data of COVID-19 in the Tokyo metropolitan area were used to perform a simulation to analyze the capability of WBE in providing early warning. The simulation result suggests that under the current settings, WBE is not a feasible approach as the detection limit is too high to provide a warning signal in the early stage of the epidemic. However, it also indicates that if the methodology can be reasonably improved by new experimental practices, optimized sampling strategy, and refined model, the concentration of viral RNA in Tokyo wastewater would exceed the detection limit as early as in April 2020, when Tokyo was being hit by the first wave of COVID-19 outbreak. This early detection may have great social benefit if the detection can be used to facilitate the decision-making process and form epidemic emergency response.

著者

Kyoshiro Hiki Fumiyuki Nakajima

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.20, no.5, pp.137-144, 2022 (Released:2022-10-10)

参考文献数

32

被引用文献数

1

---

Microplastics adversely affect organisms through physical damage, inhibition of food assimilation, and/or toxicity of chemical leachates. We investigated the influence of feeding mode on microplastic ingestion by using polystyrene microbeads (diameter: 4.1 and 20.6 μm) and the estuarine benthic amphipod Grandidierella japonica, which can switch between filter-feeding and deposit-feeding modes. When provided with sediment, amphipods burrowed and were in the filter-feeding mode; they ingested 4.1 and 20.6 μm beads in the ratio at which the two sizes were suspended in the water. Without sediment, however, the amphipods were mainly in the deposit-feeding mode and ingested more 20.6 μm beads, which tended to be deposited on the bottom, compared with 4.1 μm beads. In addition, the number of microbeads ingested by the amphipods in sediment increased as the amount of food provided (i.e., fish food TetraMin) increased, whereas no such increase was observed for the amphipods without sediment. These results indicate that the microbead ingestion was dependent on feeding mode (i.e., presence/absence of sediment), amount of food, and distribution of microbeads (i.e., sizes of microbeads). To better understand the ingestion, accumulation, and toxicity of microplastics in aquatic environments, we recommend that more attention be paid to behavioral changes in benthic organisms.

著者

Mitsuo Yamamoto Toshiaki Kato Susumu Kanayama Kota Nakase Naoto Tsutsumi

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.15, no.5, pp.186-197, 2017 (Released:2017-10-10)

参考文献数

25

被引用文献数

10

---

Reduction of seaweed beds is a serious problem in coastal areas of Japan and worldwide, and the lack of dissolved iron in seawater may contribute to the destruction of this ecologically important habitat. We have previously developed a method for restoring seaweed beds using a mixture of steelmaking slag and composts containing humic substances. Since October 2004, we have been performing field tests on the Shaguma coast in Mashike-cho, Hokkaido, Japan, to confirm the effectiveness of this method. However, thus far, no studies have been conducted to evaluate the effects of the hydrodynamic conditions by calculating the iron distributions in the area of the field tests. In this study, we evaluated the continuous effects of this iron fertilization method in Mashike by comparing the changes in seaweed bed distributions with the analyzed iron concentrations over a 5-year study period and the simulation results of iron distribution in the study area. Our findings demonstrated that the biomass of seaweeds at the fertilized (experimental) site was larger than that at the reference site. We also found that both the analyzed iron concentration and the calculated iron distribution in the area corresponded to the distribution of seaweed beds.

著者

鬼倉 徳雄 川本 朋慶

出版者

Japan Society on Water Environment

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.36, no.3, pp.99-106, 2013

被引用文献数

2

---

九州北部の主要な一級河川の水文水質および水辺の国勢調査データに,九州大学が保有する魚類相データを加えて,水質と純淡水魚類との関係を解析した。流水性魚類の種数はBODと負に相関した一方,止水性魚類の種数は相関を示さなかった。Receiver operating characteristic curve解析を行ったところ,幾つかの魚種の出現/非出現がBODに左右されていた。2001-2010年の期間は1991-2000年よりもBODが低く,魚類の出現種数が多かったことから,近年の水質改善が魚類の多様性回復に貢献したと評価される。

著者

A. H. M. Enamul Kabir Masahiko Sekine Tsuyoshi Imai Koichi Yamamoto

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.18, no.3, pp.175-194, 2020 (Released:2020-06-10)

参考文献数

103

被引用文献数

9

---

Marine microplastics pollution has been an emerging global threat. This study investigated microplastics pollution in the ‘Seto Inland Sea (SIS)’ and ‘Sea of Japan (SJ)’ surrounded Yamaguchi prefecture areas in Japan. The density separation method was applied to extract microplastics from sea surface sediment and water samples. Polymeric compounds were identified through ATR-FTIR analysis. The average microplastic abundances were 112.57 ± 121.30 items/kg in sediment and 57.46 ± 20.82 items/L in water. Abundance comparisons revealed similar level of pollution in both sea areas and medium to high-level pollution than others around the world. Characterization revealed that fragments and small microplastics (< 1,000 µm) predominated sediments. Fragments and films were major shapes in the SIS sediments while only fragments predominated the SJ sediments. Large microplastics (1,000–5,000 µm) fibers predominated water in all the areas. Transparent microplastics predominated both the sediments and water. Polyethylene, polyvinyl alcohol, and polypropylene were major polymers in sediments while polyethylene terephthalate and polyethylene predominated water. No significant correlations of microplastics abundances and characteristics were observed between sediment and water. Anthropogenic activities and environmental factors were speculated to be the main sources of microplastics in these areas. Overall, this study indicated that microplastics pollution in these marine areas could be an alarming environmental problem.

著者

志々目 友博

出版者

Japan Society on Water Environment

雑誌

水環境学会誌 = Journal of Japan Society on Water Environment (ISSN:09168958)

巻号頁・発行日

vol.29, no.8, pp.469-476, 2006-08-10

参考文献数

19

被引用文献数

1 1

---

The amounts of Co-PCB emission in Tokyo Bay basin were estimated using a multimedia environmental model, the CoZMo-POP model, which was developed for describing the long-term fate of persistent organic pollutatnts (POPs) in a coastal environment. The Co-PCB concentrations in sediment estimated using the model effectively explained the chronological changes in the concentrations in substances that settled at the bottom of sea water, which were estimated by a sediment mixing model based on the concentrations in sediment core samples. Furthermore, the estimated chronological changes in the amounts of Co-PCB emission in each year were in agreement with the chronological changes in PCB demand in Japan.

著者

Satoru Suzuki Daisuke Sano

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.21, no.2, pp.97-107, 2023 (Released:2023-04-10)

参考文献数

79

---

There is much evidence that the environment is a reservoir of antibiotic resistance genes (ARGs). For ARG latency and stability, environmental factors should play a role since ARGs are transferred among bacterial species, which results in their evolution and dissemination. Recent findings have expanded the novel mechanisms of horizontal gene transfer (HGT) beyond classically accepted HGT mechanisms such as conjugation, transformation, and transduction. In these HGT processes, environmental factors directly or indirectly affect the transfer rate and mechanism. Here, we focus on the effect of protists that affect HGT, because HGT is regulated among the microbial community, in which protist grazing is one factor that enhances HGT. Protist grazing eliminates planktonic bacteria. However, it is reported that environmental DNA release and HGT in protist vacuoles are increased by the grazing, although the effect is not uniform and depends on the environmental conditions. Biofilms protect bacteria and accelerate HGT. In these processes, quorum sensing and organic matter contribute to HGT. Although HGT occurs between bacterial cells, other microorganisms such as protists should be recognized as factors relating to HGT. We should pay attention to microbial ecosystem when consider ARG risk from water environment in terms of “one health” aspect.

著者

Rie Tai Kenta Chiba Yu Nishimura Shuping Han Shigeki Masunaga Wataru Naito

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.20, no.5, pp.118-127, 2022 (Released:2022-10-10)

参考文献数

26

---

Copper (Cu) toxicity is an increasing concern in marine environments; however, its effects are species- and area-specific. In this study, area-specific Cu toxicity test was conducted on the sensitive early life stages (i.e., embryonic and larval development) of two important fisheries species, namely, Pacific oyster (Crassostrea gigas) and sea squirt (Halocynthia roretzi) using natural sea waters collected from three sites in the coastal area of Miyagi Prefecture, Japan. Measured concentrations for C. gigas and nominal concentrations for H. roretzi were used to calculate effect concentrations for each species. The 10% effect concentration (EC10) for Cu were 12.8–17.0 and 15.0–22.0 µg L−1, and 50% effect concentration (EC50) for Cu were 20.3–22.6 and 45.6–47.2 µg L−1, respectively. Notably, this study is the first to determine the toxicity of Cu to H. roretzi, and our results can provide additional information to strengthen the Cu species sensitivity distribution of saltwater species, which can support bioavailability correction. Moreover, the results of this study can help policymakers to develop more realistic Cu water quality standard while considering the effects of Cu toxicity on important species and the water chemistry in specific regions.

著者

Do Thi My Phuong Nguyen Xuan Loc Huynh Thi Diem

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.21, no.3, pp.166-179, 2023 (Released:2023-06-10)

参考文献数

38

---

U Minh Thuong National Park is a key site for wetland biodiversity conservation in Vietnamese Mekong Delta. This paper outlines a field experiment carried out in U Minh Thuong National Park in the dry season 2019. The study aimed to compare methane emissions and related physicochemical soil and water parameters between the Peat swamp forest and Melaleuca forest. The results show that both water and soil parameters at 8 examined sites in Melaleuca forest and Peat swamp forest fluctuated highly over the sampling intervals. The average hourly C-CH4 emission rates in Melaleuca forest (26.58 mg/m2/h) was higher than that in Peat swamp forest (21.18 mg/m2/h). Generally, water level and redox potential were important factors regulating emissions of methane gases. The Eh values were all negative values, ranged between −196.5 ± 22.75 mV and −27.75 ± 15.37 mV, indicative of high electron activity and intense anaerobic. Peat swamp forest’s soil had relatively higher organic matter, CEC, TN and TP values than Melaleuca forest’s soil. The COD values fluctuated between 197.3 ± 51.78 mg/L and 396.8 ± 25.77 mg/L, indicative of organic pollution of surface water. It is suggested shorter time measurement (at least twice a day) of methane emission for more accurate evaluation.

著者

Masaya Matsuki Nobuhiro Shimizu Kazuhiro Tobiishi Yoshito Tanaka Haruyo Yamaguchi Tomoharu Sano

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.20, no.6, pp.261-272, 2022 (Released:2022-12-10)

参考文献数

34

---

Cyanotoxins produced by blue-green algae in lakes are among the most serious threats to water quality worldwide. As global warming rapidly extends the locations and timing of blue-green algae blooms, a simple and accessible method for the detection and quantification of cyanotoxins in fresh water is increasingly necessary. Here, a quick, simple and accessible simultaneous analytical method for five cyanotoxins (cylindrospermopsin, anatoxin-a, microcystin-RR, YR and LR) is reported. This method has three advantages. First, it does not require complicated operations, such as a concentration operation. Second, it employs an HPLC column without high pressure. Third, the use of stable isotope-labeled surrogates enables correct identification and precise quantification of cyanotoxins. The method was applied to the lakes of Fukuoka Prefecture in Japan, and four of the five above-named cyanotoxins (i.e., all but cylindrospermopsin) were detected. The limits of quantification were 20–43 ng/L, which were considerably lower than the WHO guideline values. The recovery levels were 97–104%. Microbial flora analysis revealed that the sources of anatoxin-a were Pseudanabaena limnetica and Cuspidothrix issatschenkoi, and the source of microcystins was the group A1 of Microcystis aeruginosa. This study provides a quick, easy and accessible method for the worldwide monitoring of cyanotoxin levels.

著者

Naoyuki Kishimoto Atsuya Kitamura

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.20, no.5, pp.128-136, 2022 (Released:2022-10-10)

参考文献数

19

被引用文献数

1

---

In an electrolytic water treatment, electrode reactions for pollutant removal can be easily controlled by changing an electrode potential. Thereby, it has a potential to realize an efficient water treatment process. However, its coulombic efficiency, η, strongly depends on reactant concentrations near electrodes. In a continuous electrolysis, the reactant concentrations near an electrode is lower than that in the bulk due to electrolytic consumption of reactant, which gives a negative impact on the η. Therefore, an introduction of intermittent electrolysis instead of the conventional continuous one was discussed in this research, where the reactant concentration near the electrode is recovered during the electrolysis-off stage. The intermittent electrolysis of 1 mM formic acid solution revealed that the η of formic acid removal under electrolysis-on/off time cycle of 1/10 s was 3.3 times higher than that under the continuous electrolysis. A popular technique to keep the reactant concentration near the electrode is an increase in the linear velocity of solution on the electrode. However, the η at a linear velocity of 20 cm/s was only ≤ 25% higher than that at 10 cm/s. Thus, the intermittent electrolysis was very effective in enhancing the energy-efficiency of electrolytic water treatment.

著者

Naoyuki Kishimoto Koki Hara

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.19, no.6, pp.283-293, 2021 (Released:2021-12-10)

参考文献数

29

---

This study reports the availability of seawater as an economical chloride (Cl−) source for the UV/electro-chlorine process from the viewpoints of advanced oxidation performance and unwanted byproduct formation of chlorate ion (ClO3−) and bromate ion (BrO3−). In the electrochemical oxidant production stage, the oxidant production rate in diluted seawater containing 30 mM Cl− was 21% lower than that in the NaCl solution due to coexisting electrolytes in the seawater. The ClO3− formation during electrolysis was successfully inhibited under acidic conditions and BrO3− formation was not detected in the diluted seawater. However, ClO3− and BrO3− were steadily formed in the undiluted seawater electrolysis, even when the initial pH value was set to 3. The oxidant utilization efficiency for 1,4-dioxane removal during UV irradiation was not deteriorated in the diluted seawater but decreased under basic conditions due to the radical scavenging effect of electrochemically produced free bromine and free chlorine. As a result, the formation of BrO3− and ClO3− was enhanced under basic conditions, whereas BrO3− formation was completely inhibited at an initial pH ≤ 5. Consequently, the diluted seawater was thought to be available as a Cl− source for the UV/electro-chlorine process if an acidic condition was maintained throughout the operation.

著者

Shuai Zhou Manae Ninoseki Asahi Kusaba Kazuma Nakagawa Taro Urase

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.19, no.6, pp.294-301, 2021 (Released:2021-12-10)

参考文献数

33

被引用文献数

1

---

Membrane bioreactor-reverse osmosis process (MBR-RO) is widely applied in wastewater treatment, especially when high-quality treated water is needed. Although MBR shows better performances in the removal of pathogens than the conventional activated sludge process, stable operation of RO process in the latter step of MBR-RO depends on residual bacteria in the filtrate of microfiltration membranes. Species and sizes of bacteria found in the filtrate of activated sludge with 0.2 μm pore-size polycarbonate membranes were investigated in this study. Isolated bacterial species grown on R2A agar medium were identified based on the full length 16S rRNA gene sequences. The result showed that approximately 90% of the isolates found in the filtrates were members of phylum Proteobacteria in which Ralstonia spp., Achromobacter spp., Methylobacterium spp. and Methylorubrum spp. accounted for the largest proportions while other bacteria affiliated with phyla Actinobacteria and Firmicutes. The leakage of Ralstonia and Actinobacteria was probably due to their small sizes judging from microscopic observation, while a longer filtration time is needed for Methylobacterium and Methylorubrum to be detected in the filtrate.

著者

Jun Jin Takashi Kusui

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.17, no.4, pp.218-230, 2019 (Released:2019-08-10)

参考文献数

38

被引用文献数

1

---

Sewage effluent plays an important role in regional water cycles and is gaining attention. Because a wide variety of chemicals are used in industry and daily life, the environmental impacts of trace chemicals in sewage effluents are a source of concern. Whole effluent toxicity (WET) testing uses biological responses to directly evaluate the toxicity of chemical substances in effluent. In contrast, the Japanese Pollutant Release and Transfer Register (PRTR) system provides estimated amounts of potentially hazardous chemicals released in effluent from factories and sewage treatment plants. The objectives of this study were to evaluate the ecological impacts of sewage effluent using WET tests and PRTR data and to compare the results from the two approaches. Of seven effluent samples tested, four demonstrated toxicities to aquatic organisms. Water analyses suggest that residual chlorine is responsible for toxicity to algae, while linear alkyl benzene sulfonates do not contribute to toxicity. The PRTR data tended to overestimate toxicity in comparison to the observed toxicity. The causes of this discrepancy are discussed, such as insufficient data. Due to the difference in calculation method, PRTR data of sewerage tends to be overestimated.

著者

Shohei Otomo Akihiko Terada Yu-You Li Kazuya Nishitoba Fumiaki Takakai Kunihiro Okano Naoyuki Miyata Shuhei Masuda

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.19, no.3, pp.139-152, 2021 (Released:2021-06-10)

参考文献数

54

被引用文献数

1

---

In full-scale sewage treatment plants, long-term and high-frequency monitoring is required to mitigate nitrous oxide (N2O) emissions. In this study, the profile of the dissolved N2O concentration in a full-scale oxidation ditch reactor was investigated to determine the variation of the N2O emission factor. It was found that the concentration of dissolved N2O depended on microbial activity, which is affected by water temperature, dissolved oxygen concentration, and the dimensional relationship between the rotator and the inflow point. In the reactor, higher transcription levels of amoA mRNA and lower transcription levels of clade II type nosZ mRNA may be associated with N2O production. The emission factor for removed dissolved inorganic nitrogen presented a mean value of 0.86% and a median of 0.19%. When N2O production was promoted, gasification from the water surface was the most significant emission source, accounting for 52% of the total N2O emitted, on average. The N2O emission factor was often lower than 0.01% during stable operation; however, this factor was subject to sudden increases caused by nitrite accumulation.

著者

Rina FEBRINA Masahiko SEKINE Hiroshi KANEMOTO Koichi YAMAMOTO Ariyo KANNO Takaya HIGUCHI Tsuyoshi IMAI

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.13, no.1, pp.77-87, 2015 (Released:2015-02-10)

参考文献数

9

被引用文献数

1 1

---

A stone-embedded fish passage (SEF) allows fish to pass a barrier by reducing the velocity in the slope. The efficiency of SEFs has however not been evaluated well and the design parameters are not clear. The efficiency of SEFs for fish therefore needs to be evaluated and analyzed. In this research, we attempted to develop a simple equation to estimate the passability of an SEF for Ayu (Plecoglossus altivelis), which is applicable in the SEF's designing stage. We reproduced the SEF conditions experimentally. The set-up consisted of a pool and a channel, and evaluated its passability based on physical conditions such as air bubbles, velocity, and depth. With the results, we developed a decision tree to explain the passability using design variables such as discharge, channel slope, and pool size and depth. Then, to estimate the whole SEF, we proposed an equation which calculated the average of the decision tree outputs throughout the SEF's whole ascending routes. Lastly, we verified the equation through field experiments. The equation showed good agreement with the observed fish ascent success rate. This technique could therefore be used to evaluate a SEF in its designing stage.

著者

Micky Vincent Fazidah Junaidi Lesley Maurice Bilung Nurashikin Suhaili Awang Ahmad Sallehin Awang Husaini Devagi Kanakaraju

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.18, no.4, pp.254-263, 2020 (Released:2020-08-10)

参考文献数

33

被引用文献数

2

---

Industrial sago starch extraction from the sago palm (Metroxylon sagu) generates large volumes of wastewater, known as sago effluent that is generally discharged into nearby water bodies without proper treatment. This practice has led to severe environmental pollution that prompts the development of biotechnological treatments of sago effluent. In this study, Rhizopus oligosporus was grown in sago effluent at several initial pHs (pH 4, 5, and 6) during submerged fermentation to determine the optimum pH for high protein fungal biomass (HPFB) production while simultaneously reducing the starch content and high organic loads of sago effluent. Our results showed that the growth of R. oligosporus was the highest (3.8 g/L) when the initial pH of the sago effluent was 4. The same pH also gave the best reduction of starch, biochemical oxygen demand and chemical oxygen demand of the sago effluent following the R. oligosporus fermentations, which were 96.70%, 89.81%, and 78.30%, respectively. In addition, nitrate concentration was found to be reduced from 0.266 to 0.257 g/L, while the nitrite level dropped from 0.040 to 0.029 g/L. The present findings presented the potential of R. oligosporus for the production of HPFB as well as for treating sago effluent.

著者

白井 康子 池田 滋 伊藤 英夫 横井 聰

出版者

Japan Society on Water Environment

雑誌

水環境学会誌 = Journal of Japan Society on Water Environment (ISSN:09168958)

巻号頁・発行日

vol.32, no.12, pp.661-664, 2009-12-10

被引用文献数

3

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Japanese rose bitterling, <I>Rhodeus ocellatus kurumeus</I>, is an endangered freshwater fish in Japan. Both the expansion of the habitat of an alien subspecies, <I>R. o. ocellatus</I>, and the increased chances of hybridization between the two subspecies have threatened the genetic identity of <I>R. o. kurumeus</I>. To conserve <I>R. o. kurumeus</I> in Kagawa Prefecture, 17 populations were genetically monitored in 2006. Two individuals in a pond were found to harbor <I>R. o. ocellatus</I> type mitochondrial DNA through PCR-RFLP analysis. Then the contaminated population was transplanted to a closed Bio-top water system to prevent contamination in other ponds. Three-day pond drying was found to be insufficient to eradicate <I>R. ocellatus</I>.

著者

Nan Wei Fumiyuki Nakajima Tomohiro Tobino

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.17, no.3, pp.153-162, 2019 (Released:2019-06-10)

参考文献数

37

被引用文献数

6

---

Environmental DNA (eDNA) is a non-invasive and less labor-intensive tool for biological survey. The advantages enable more frequent sampling work, but there is a lack of fundamental field data on the variation of eDNA in sediment in different timescales. We conducted a yearlong sampling at two marine parks of Tokyo Bay (Odaiba Marine Park and Kasai Marine Park) to investigate the temporal variation of sediment eDNA at scales of one year, one month and one tidal period. Grandidierella japonica, an indicator benthic species of water quality in Japan and also an invasive species in other countries, was chosen as target species. In yearlong scales, the total eDNA content and the copy number of the amphipod eDNA in both parks showed a seasonal variation pattern as low in cold season (89 ± 14 ng DNA/g sediment, 583 ± 64 copies/g sediment) and high in warm season (884 ± 97 ng DNA/g sediment, 9,501 ± 3,553 copies/g sediment). In scales shorter than one month, eDNA kept stable and did not show clear variation. The results indicated that eDNA in sediment is useful for biological survey by reflecting the well-averaged state of the species abundance in the environment and not showing the erroneous sudden variation in a short timescale.

著者

Hirofumi Tsutsui Taro Urase

出版者

Japan Society on Water Environment

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.17, no.3, pp.194-202, 2019 (Released:2019-06-10)

参考文献数

21

被引用文献数

3

---

16S rRNA gene copy numbers and bacterial counts in the permeate from different microfiltration membranes installed in membrane bioreactors (MBRs) were measured in order to provide information on the selection of suitable membrane for wastewater reclamation and reuse. 16S rRNA gene copy numbers in the MBR effluent (105 − 107 gene copies / mL) were 1/5 to 1/500 of those in the centrifugal supernatant of the mixed liquor. High bacterial counts and high gene copies were observed in the permeate of the membranes at the beginning of the filtration stage. The permeate contained bacteria without exceptions by using a 0.4 µm or larger pore size membrane, although the passage of bacteria was sporadic by the use of a membrane with cylindrical pores of 0.2 µm diameter. Acinetobacter junii and Microbacterium fluvii were identified in the permeate of the 0.2 µm pore size membrane based on the closest match of 16S rRNA gene sequence. The possibility of selective passage of small size bacteria in the mixed liquor of activated sludge through the membrane was suggested.