Tsurumi River Research Articles

Assessment of microplastic occurrence in tidal flat biota of the Tsurumi River estuary (Tokyo Bay, Japan): Preliminary study and first evidence

As concerns grow over the detrimental impacts of microplastics (MPs) on aquatic ecosystems, understanding their dynamics in Japanese biota has become increasingly urgent. We identified and compared MPs (diameter 20–5000 µm) in 11 organisms (fish, invertebrates, and a macroalga) and in sediments in the Tsurumi River estuary, Japan. A total of 1260 MPs were detected across all samples. The most common polymer was polyethylene (n = 492), followed by polypropylene (136) and polyamide (120). The mass concentration of MPs entangled in macroalgae was approximately two orders of magnitude higher than in sediment by wet weight. While there seemed to be no indication of increased bioaccumulation of MPs via trophic transfer, the results suggest that MP accumulation in macroalgae might play an important role in adverse effects of MPs on tidal flat organisms. Due to additional technical challenges, we were unable to process many samples. Further work is needed to clarify the dynamics of MPs in this area.

Database of fish fauna in a highly urbanised river (Tsurumi River Basin, Kanagawa, Japan).

Urbanisation has facilitated changes in the hydrological cycle, sediment dynamics and habitat loss and it has had a tremendous impact on river ecosystems. Moreover, the invasion of non-native species reduces the number of native species with the progress of urbanisation, thereby resulting in the homogenisation of fish fauna and significant decrease in diversity. However, the effects of urbanisation on fish fauna vary depending on the region, degree of urbanisation and number of years since the construction of the city. Hence, it is necessary to collect information on how fish fauna changes due to urbanisation in different regions. The target site of the present study is the Tsurumi River, of which approximately 85% of the basin is urbanised and many of the river channels have been affected by straightening and concrete channelling. Monitoring of biota has been conducted mainly in downstream areas; however, data on fish fauna in upstream areas and tributaries of the river, which have been substantially affected by urbanisation, are lacking. Surveys were conducted at 71 sites in the Tsurumi River Basin during summers and winters, focusing on river channels that have been straightened or converted to concrete channels due to urbanisation. As a result of this investigation, 10 families, 28 species and 9,335 individuals were collected. Some of the fish collected included rare species, such as Tanakialanceolata, Lefuaechigonia and Pseudobagrustokiensis, indicating that, even in rivers that have been severely impacted by human activities, there are still rare indigenous species living there, albeit in limited numbers. In addition, Misgurnus sp. (clade B2), Micropterussalmoides, Lepomismacrochirus and Poeciliareticulata were confirmed to be non-native species. Misgurnus sp. (clade B2) was widespread; however, populations of carnivorous non-native alien species were small. The data are all accessible from the document "database_fish_urban_tsurumi" (https://ipt.pensoft.net/manage/resource?r=database_fish_urban_tsurumi).

都市河川にみる治水システムと遊水地の意義（I）:―鶴見川を例として―

都市河川にみる治水システムと遊水地の意義（I）:―鶴見川を例として―

The Role of the Spatial Distribution of Radar Rainfall on Hydrological Modeling for an Urbanized River Basin in Japan

Recently, the use of gridded rainfall data with high spatial resolutions in hydrological applications has greatly increased. Various types of radar rainfall data with varying spatial resolutions are available in different countries worldwide. As a result of the variety in spatial resolutions of available radar rainfall data, the hydrological community faces the challenge of selecting radar rainfall data with an appropriate spatial resolution for hydrological applications. In this study, we consider the impact of the spatial resolution of radar rainfall on simulated river runoff to better understand the impact of radar resolution on hydrological applications. Very high-resolution polarimetric radar rainfall (XRAIN) data are used as input for the Hydrologic Engineering Center–Hydrologic Modeling System (HEC-HMS) to simulate runoff from the Tsurumi River Basin, Japan. A total of 20 independent rainfall events from 2012–2015 were selected and categorized into isolated/convective and widespread/stratiform events based on their distribution patterns. First, the hydrological model was established with basin and model parameters that were optimized for each individual rainfall event; then, the XRAIN data were rescaled at various spatial resolutions to be used as input for the model. Finally, we conducted a statistical analysis of the simulated results to determine the optimum spatial resolution for radar rainfall data used in hydrological modeling. Our results suggest that the hydrological response was more sensitive to isolated or convective rainfall data than it was to widespread rain events, which are best simulated at ≤1 km and ≤5 km, respectively; these results are applicable in all sub-basins of the Tsurumi River Basin, except at the river outlet.

A Geographical Study on the Dissolving Process of the Flood Prevention Cooperative by Analyzing Its Flood Prevention Imposition System--The Case of the Tsurumi River Flood Prevention Cooperative in Kanagawa Prefecture

A Geographical Study on the Dissolving Process of the Flood Prevention Cooperative by Analyzing Its Flood Prevention Imposition System--The Case of the Tsurumi River Flood Prevention Cooperative in Kanagawa Prefecture

Stakeholders' Participation in Sustainable Water Resource Management, Lessons from Tsurumi River for Muda River Basin

Rivers in Malaysia play an important role in regional economic development as well as water source for industrial, domestic, agricultural, aquaculture, hydroelectric power generation, and environment. The aim of this research is to examine the applicability of lessons drawn from the Tsurumi River Basin for improving the management of the Muda River Basin in Malaysia as well as highlighting the major problems in existing water resources management in Muda River Basin address the problems. There is little or no stakeholders involvement in Muda River Basin and water resource management is not holistic and not integrated as it should be. Besides that, there is little or no Integrated Resources Water Management, a pre‐requisite for sustainable water resources. It is concluded that full support and participation from public stakeholders (meaning the non‐government and non‐private sector stakeholders) are important factors towards an integrated water resources management (IWRM) approach for sustainable water use in Muda River Basin.

Levels and distribution of hexabromocyclododecane and its lower brominated derivative in Japanese riverine environment

Hexabromocyclododecane (HBCD) and its lower brominated derivatives were measured in both surface water and sediment samples from three Japanese rivers; Tsurumi River, Yodo River, and Kuzuryu River. The concentration level of ∑HBCD (sum of α-, β-, and γ-HBCD) was in the order of Kuzuryu>Yodo>Tsurumi Rivers, reflective of the different emission sources for each basin. The highest ∑HBCD concentration (7800ngg−1dw) was detected in the sediment sample from the Kuzuryu River that receives effluents from textile industries, which use HBCD in flame retardant finishes. A different diastereomeric pattern of α-, β-, and γ-HBCD of each river was investigated, indicating the level of HBCD in these rivers is directly influenced by emission source. Enantiomer fractions of HBCDs in water and sediment samples were also determined. Racemic mixtures were observed in the water samples, whereas enantiomeric enrichment of (−) γ-HBCD and (+) α-HBCD was observed in the sediment samples. Some lower brominated HBCD derivatives such as pentabromocyclododecenes were detected in both the water and sediment samples, and their concentration ranged from below the detection limit to 15ngL−1 and 20ngg−1dw, respectively.

低平地都市河川におけるリアルタイム洪水シミュレーションモデルの開発

This study aims to develop a real time flood simulation model in an urbanized low-lying river basin (Tsurumi river of Japan). The model has been developed by enhancing the distributed hydrological model (WEB-DHM) to account for urban land surface characteristics and effects of flood control ponds and coupling 1D unsteady flow model to the enhanced WEB-DHM. The enhanced WEB-DHM model computes the flow rate in the upper stream and the 1D unsteady flow model computes the time-varying water surface level in the lower stream accounting for tides and effects of retention ponds. The system has been validated against past flood events along the study region with acceptable accuracy.

Geographical Study on the Relationship between Change of Land Use and Flooding in the Tsurumi River Basin

Geographical Study on the Relationship between Change of Land Use and Flooding in the Tsurumi River Basin

Seasonal and spatial distribution of trace elements in the water and sediments of the Tsurumi River in Japan

The Tsurumi, a class-one Japanese river, has a significant metal loading originating from urban environment. Water and sediment samples were collected from 20 sites in winter and summer, 2009 and were analyzed to determine and compare the extent of different trace element enrichment. A widely used five-step sequential extraction procedure was also employed for the fractionation of the trace elements. Concentrations of zinc, copper, lead, chromium, and cadmium were three to four times higher than that of reference values and downstream sediments are much more polluted than the upstream sites. Geochemical partitioning results suggest that the potential trace metal mobility in aquatic environment was in the order of: cadmium > zinc > lead > copper > cobalt > chromium > molybdenum > nickel. About 80.2% zinc, 77.9% molybdenum, 75.3% cobalt, 63.7% lead, 60.9% copper, 55.1% chromium, and 39.8% nickel in the sediment were contributed anthropogenically. According to intensity of pollution, Tsurumi river sediments are moderately to heavily contaminated by zinc, lead, and cobalt. Enrichment factor values demonstrated that zinc, lead, and molybdenum have minor enrichment in both the season. The pollution load index (PLI) has been used to access the pollution load of different sampling sites. The area load index and average PLI values of the river were 7.77 and 4.93 in winter and 7.72 and 4.89 in summer, respectively. If the magnitude of pollution with trace metal in the river system increases continuously, it may have a severe impact on the river's aquatic ecology.

Determination of EDTA in Water Samples by SPE-Gas Chromatography/Mass Spectrometry

Japan's recommended method of EDTA determination is complex and time-consuming. In this study, a new method to prepare the solution to determine EDTA in water by solid-phase extraction-GC/MS was developed. Recovery yields were excellent with values ranging from 98.1 to 100.5%. Due to this method's ease and simplicity, it is suggested that this approach be adopted as Japan's recommended method for EDTA analysis. The method was applied to assess the concentrations of EDTA in river water from three regions of Japan. Median concentration of EDTA in river water samples was 115 μg/L, and the concentrations ranged from 18.8 to 443 μg/L. The highest concentration of EDTA (443 μg/L) was observed in Tsurumi River. Sewage treatment plant (STP) effluent significantly contributed to high EDTA levels.

Geochemical distribution of trace metal pollutants in water and sediments of downstream of an urban river

A study was conducted to investigate the trace metal pollution of water and sediments of downstream of Tsurumi River, Yokohama, Japan. Twenty samples of water and sediments were collected from the river starting from Tokyo bay side up to the junction point of the Yagami River. Results show that the mean concentrations of chromium, cupper and nickel in water greatly exceed (>100 times) the surface water standard. The concentration of molybdenum and lead was also higher than standard values while iron and manganese was lower than that of surface water standard. The mean concentration of zinc, cupper, cadmium, lead, chromium, vanadium, bromine and iodine was 381.1, 133.0, 1.0, 40.8, 102.9, 162.0, 71.5 and 10.6 µg/g sediments, respectively and was greatly exceed the average worldwide shale concentrations and average Japanese river sediment values. However, mean concentration of arsenic, nickel and strontium was 11.0, 36.6 and 164.6 µg/g sediments, respectively which was lower than the average shale value. Other analyzed trace metals, including barium, zirconium, rubidium, yttrium, tin, antimony, cesium, lanthanum, cerium, praseodymium and neodymium were detected in river sediments; the concentration of which was close to the Japan's river sediment average values. Pollution load index values of the sites of the studied area ranged from 1.24 to 7.65 which testify that the river sediments are polluted. The PLI value of the area was, however, high (6.53) as the concentration of trace metals like zinc, cupper, cadmium, lead and chromium were very high and were the major pollutants.

Optimal control of drainage basin considering moving boundary

The purpose of this article is to present a technique to optimally control river flood using a drainage basin considering a moving boundary. The main theme of this article is to obtain outflow discharge from the drainage basin that maintains the water level at a downstream point and empties the drainage basin as soon as possible. The water flow phenomenon inside the drainage basin when a river flood occurs is considered. This phenomenon can be analysed by the finite element method considering a moving boundary. The optimal control theory can be implemented to obtain the optimal control discharge. The finite element analysis with a moving boundary is introduced in the optimal control theory. A new boundary condition on the downstream side of the river is proposed. This condition is formulated by the solitary wave condition based on the basic water level being capable of representing natural water surface. As a numerical study, optimal control of shallow water flow is carried out for the Tsurumi River and its drainage basin model.

Existence of nonpoint source of perfluorinated compounds and their loads in the Tsurumi River basin, Japan

Products containing perfluorinated compounds (PFCs) have been widely used during the last 50 years. As a result, worldwide environmental pollution by PFCs has been reported. The sources of PFC pollution in the aquatic environment have been poorly understood. In this study, river water and sewage treatment plant (STP) effluent were sampled along the stretch of the Tsurumi River and also at a fixed station in the river. The concentrations of perfluorooctanesulfonate (PFOS), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were measured. With an increase in river flow rate, it was observed that the PFC concentrations in the river water at fixed station were remained the same or increased for PFOS (179.9 ± 34.4–179.6 ± 69.5 ng l −1), PFHxA (5.5 ± 0.8–9.0 ± 2.6 ng l −1), PFHpA (3.1 ± 0.3–4.4 ± 1.0 ng l −1), and PFOA (15.9 ± 0.3–13.4 ± 2.5 ng l −1) whereas the concentration of PFNA (38.0 ± 3.3–15.4 ± 3.0 ng l −1) and PFDA (3.9 ± 0.3–2.1 ± 0.3 ng l −1) were decreased. On the other hand, the loads of every PFC increased with an increase in river flow rate. The loads of PFCs in rain runoff were estimated to be 2–11 times greater than those in STP effluents that are discharged into the river. These results indicate the existence of a PFC nonpoint source (NPS) and its impact to the total PFC load of river is significant.

Optimal control of shallow water flow using time-delay function

This paper presents an optimal control system that includes a time-delay function for application to flood control setups with a retardation area. This system consists of the present and past controls that express flow behaviour in the retardation area. Optimal control theory is used to obtain a control discharge that satisfies the state equation including the time-delay function and minimizes the performance function. The optimal control and the delayed control discharges are obtained by the solution of an adjoint equation. The weighted gradient method is employed as a minimization algorithm. The Galerkin finite element procedure is employed to discretize the state and adjoint equations in the spatial direction. The bubble function interpolation, originated by the authors' group, using a stabilized term, is employed for the discretization in space. The flood flow in the Tsurumi river is presented as a numerical model. We show in this paper that floods can be controlled by means of a time-delay function.

An Optimal Control of Water Level Considering Time-Delay System

This paper presents a numerical application of the optimal control considering time- delay system to the flood control with drainage basin. The optimal control theory is used to obtain the control values which satisfies the state equation and minimizes performance function. Feature of this study is application of time-delay system to control problems. Two kinds of control values which has time difference can be introduced. Those are quantity of water intake and release in drainage basin. These control values are correlated with each other, which can be modeled by the time-delay system. The Sakawa-Shindo method is employed for the minimization algorithm. To calculate the water flow phenomenon, the shallow water equation is employed. The Clank-Nicolson method is applied to temporal discretization and the stabilized bubble function method is applied to spatial discretization. As the numerical model, the flood flow in the Tsurumi river which locates in Yokohama city is represented.

SIMULATION OF THE EFFECTS OF STRUCTURAL SCALE OF DETENTION FACILITIES ON FLOOD CONTROL

Stormwater detention facilities have been used to reduce flood runoff from urbanized areas. They are recognized as means to reduce peak flows of downstream rivers, and it is needed that the planning of them are done on a watershed-wide basis. In this paper a method to estimate the flood control effects of detention facilities on a watershed-wide basis, and the results of its application to Tsurumi river basin are presented. We could estimate the flood control effects of detention facilities by comparing the hydrographs calculated by the present method for Tsurumi river basin with and without detention basins respectively. It is found that there was little effect on flood control of the small scale detention facilities.

東京湾流入河川におけるダイオキシン類の輸送量と発生源

The amounts of dioxins (PCDD/Fs) and dioxin-like PCBs transported by rivers from various sources to Tokyo Bay were estimated. River water samples were collected at six stations in six different rivers (Edo River, Naka River, Ara River, Sumida River, Tama River and Tsurumi River) from April 2001 to July 2003, and the concentrations of PCDD/Fs and dioxin-like PCBs in these rivers were determined. On the basis of these results, the annual amounts of PCDD/Fs and dioxin-like PCBs transported by each river to Tokyo Bay were estimated. It was estimated that 10 g-TEQ (particulate phase) and 2.3 g-TEQ (dissolved phase) were transported to Tokyo Bay annually in recent years. Also, the contributions of sources of PCDD/Fs and dioxin-like PCBs in these rivers were estimated by a chemical mass balance (CMB) approach. In Tama and Tsurumi Rivers, it was estimated that more than 85% of total TEQ originated from combustion, while the contribution of combustion was less than 60% in the Ara River. Moreover, the amounts of PCDD/Fs and dioxin-like PCBs transported from each source were estimated, assuming that the contributions of sources in a river are constant in recent years. It was estimated that 8.4 g-TEQ, 1.1 g-TEQ, 0.45 g-TEQ, 1.2 g-TEQ originating from combustion, PCP, CNP and commercial PCBs, respectively, were transported to Tokyo Bay annually.

Biological Evaluation of the Pollution of the Tsurumi River with 7-Ethoxycoumarin O-Deethylase Activity Induced by River Sediment Extracts in HepG2 Cells.

The pollution level of the Tsurumi River flowing into Tokyo Bay was studied longitudinally using river sediment extracts in an assay system based on the arylhydrocarbon receptor (AhR)-dependent induction of 7-ethoxycoumarin O-deethylase (ECOD) activity in HepG2 cells. The sampling points of river sediment were as follows: Namamugi, Kami-Sueyoshi, Tsunashima, Shin-Yokohama A and B (downstream and upstream, respectively, from the former open-air industrial waste incineration site), Kozukue and Nakayama (Fig. 1). ECOD activity was induced to different extents in all samples tested. Namamugi, located in the middle of Keihin Industrial District, was considered to be the most polluted, followed by Shin-Yokohama A and Tsunashima. Results from these samples showed reverse U-shaped dose-response curves in terms of ECOD activity as well as 3-methylcholantrene (3-MC) although the expression of CYP1A1 mRNA in HepG2 cells remained roughly constant at higher concentrations as in the case of 3-MC, thus implying post-transcriptional suppression.

Biological Evaluation of the Pollution of Rivers Flowing into Tokyo Bay with the 7-Ethoxycoumarin O-deethylase(ECOD) Activity Induced by River Sediment Extracts in HepG2 Cells.

The extent of pollution in the rivers flowing into Tokyo Bay was studied comparatively using river sediment extracts in an assay system based on the arylhydrocarbon receptor (AhR)-dependent induction of 7-ethoxycoumarin O-deethylase (ECOD) activity in HepG2 cells. The sampling points of river sediment were as follows: Namamugi on the Tsurumi River, Rokugo on the Tama River, Hirai, Senjyu and Funado on the Ara River, Baraki on the Edo River, and Makuhari on the Hanami River (Fig. 1). The Tsurumi River (Namamugi) located in the middle of Keihin Industrial District was considered most polluted, followed by the Ara River (Hirai). The river sediment collected at Baraki on the Edo River was least polluted. The extracts of highly polluted river sediments sampled at Namamugi and Hirai exhibited a reverse U-shaped dose-response curve, for which polycyclic aromatic hydrocarbons (PAHs) might be mainly responsible, in a range of non-toxic concentrations. The pollution of river sediment collected at Namamugi was roughly estimated to be 2 to 20 μg as PAHs/g sediment by consulting the data of Nakama et al. and 0.2 to 2 μg as PAHs/g was assigned to the river sediment of Hirai.