Takanobu Inoue

• Professor (Full) at Toyohashi University of Technology

Plastic pollution has become a major environmental threat, with extensive research focusing on the transfer of plastic waste from urban areas to oceans. However, limited attention has been given to the role of agricultural areas in plastic emissions to rivers. Rivers play a crucial role in transporting plastics to the ocean. This study investigates...

Chlorine is the most common disinfectant in drinking water worldwide, and the free residual chlorine concentration has been stipulated at least 0.1 mg/L according to Japanese drinking water standard to ensure disinfection efficacy during distribution. In addition, Japan is also applying approximately 0.4 mg/L chlorine at treatment plants to supply...

In urbanization, understanding of water consumption is necessary for water supply infrastructure development. We have been studying water consumption at Iride-Chibata District in the development of water supply management in Kosai City, Shizuoka Prefecture, Japan. Here the water consumption has been managed by reading water meter at each household...

Microplastics have negative chemical and ecological effects on aquatic biota and humans. However, few studies have explored the abundance of microplastic in rural river. This study aims to compare of the abundance of microplastic, size distribution, color, and polymer types in rural river of Japan and Indonesia. Data were collected at one of river...

In urbanization, understanding of water consumption is necessary for water supply infrastructure development. We have been studying water consumption at Iride-Chibata District in the development of water supply management in Kosai City, Shizuoka Prefecture, Japan. Here the water consumption has been managed by reading water meter at each household...

Smart meters monitor hourly water consumption patterns while reducing the cost and inconvenience of traditional meters. This study comprehensively analyzes 1871 households that previously used traditional meters from the distribution point to the distribution area. All the households were equipped with smart meters and the data collected were used...

Sweet basil (Ocimum basilicum L.) is a highly profitable crop grown in commercial plant factories, primarily valued for its aromatic profile rich in essential oils that offer positive health effects. Cultivated hydroponically under artificial light conditions, the plant’s light environment, including intensity, photoperiod, and spectrum, can be eas...

In this study, we developed a plant air purification system. We evaluated the performance and effectiveness of the system. The results are as follows. 1. The air permeability coefficient of the mixed medium was approximately 6.3 and 1.4 times higher than that of Akadama Soil and Seramis. 2. The removal rates of formaldehyde under soil aeration cond...

To reduce aquatic eutrophication, measurements of bioavailable phosphorus (BAP) rather than total phosphorus (TP) are deemed critical. However, current methods require much time to separate sediments from river water, which limits the routine measurement of BAP in rivers. Therefore, in this study, a simultaneous multisample ultrasonic extraction me...

This study critically evaluated the potential of Refuse Derived Fuel (RDF) as a sustainable substitute for coal in the cement manufacturing process. Using Emplacement Pluit's waste as a primary source, three distinct RDF variations were analyzed: RDF A (comprised purely of PET Charcoal), RDF B (a 50-50 combination of PET Charcoal and organic waste)...

Marine debris in Jakarta is a complex problem because the amount is too large every day. Addressing this critical gap, this study proposes a model for efficient waste transportation through the development of an Intermediate Transition Station (ITS) system. This system not only facilitates the effective movement of waste but also incorporates a rec...

Plastics can long persist in nature to become an environmental issue if not taken care of properly. To understand factors affecting plastic pollution in Japan’s farmland Hamada River, this study examined quantification of macroplastics (those larger than 5 cm) during differing weather conditions. The average number of collected samples in unit area...

Sampah perairan di Tempat Penampungan Sementara (TPS) Jakarta memberikan beban polusi yang signifikan akibat aktivitas manusia. Pemulihan energi menyajikan peluang untuk mendapatkan nilai dari puing-puing ini dan mencapai solusi limbah nol. Di antara komponen limbah di TPS Perintis, puing kayu dari puing-puing sungai di Jakarta mendominasi. Penelit...

Nutrient measurement to control eutrophication in closed water environment is an approach toward sustainable development. Accurate as well as fast measurements are vital to determine agricultural land use, watershed construction or urban planning. The nutrients, mainly nitrogen and phosphorus, contributing to eutrophication are clarified as rather...

Microplastics are concerning pollutants with increasing global presence. Yet, data on theiroccurrence in Indonesian rivers, especially in Semarang, is limited. This study aimed to assessmicroplastic abundance and characteristics in Greater Semarang's Babon and East Flood Canal(Kanal Banjir Timur, KBT) rivers at five stations. Sampling and analysis...

Many land-based plastic pollutants are transferred by river-based sources. This study examined the accumulation of macroplastics (plastics larger than 5 cm) on the banks of a farmland river in Japan’s Aichi prefecture to evaluate the plastic influx from agricultural sources. The samples were collected manually and through visual inspection. The col...

Smart water meters in households monitor hourly consumption patterns while mitigating the cost and inconvenience associated with traditional manual meters. This study comprehensively analyses 1871 households that previously used traditional manual water meters from the distribution point to the distribution area. All the households are equipped wit...

A system was developed for measuring the time course of photosynthesis and transpiration. The system was applied to ornamental plants in an office under different root environmental conditions: soil and non-soil aerations. This system composes an automated-closed chamber and a sensing unit. The shoot part of a fully grown ornamental plant enclosed...

Marine plastic pollution has become a global concern as plastic wastes continue to accumulate in the world’s oceans. Usually, such accumulation occurs due to garbage leakage from land, which eventually flow into the river pathways through surface runoff or wind. This study aims to draw a parallel between the garbage influx of two rural rivers in In...

To reduce watershed eutrophication, measurements of bioavailable phosphorus (BAP) rather than total phosphorus (TP) are deemed critical. However, standard methods for direct and routine BAP measurement in river water have not been widely investigated. Therefore, in this study, a simultaneous multisample ultrasonic extraction method is proposed to m...

The waste from the river is one of the obstacles in managing the Bengawan Solo River, Surakarta City. River debris is usually collected in tributaries so as not to carry the pollutant load to the watershed, causing flooding, and then transported to the Final Processing Site (TPA). This study aims to analyze the waste transportation system from the...

Zinc is frequently reacting with inorganic species in water to form zinc species. Thus, the chemical speciation of Zinc in the aquatic environment has become a significant concern nowadays due to its adverse effect on humans and its potential toxicity in the water system. In this study, to investigate the interaction between dissolved zinc and hydr...

Plastic pollution in the ocean primarily originates from the land-derived mismanaged plastic waste that is transported by rivers. This study aimed to estimate the plastic litter generation in the surface water in Jakarta and Indonesia. A field survey was conducted at six riverine sampling points (upstream to downstream) and three holding facilities...

River debris is the main problem from the negative impact of poor waste management. The composition of river debris in Jakarta consists mostly of plastic waste. Plastic waste from river debris has an opportunity for energy recovery. This study aimed to see the potential for utilizing river debris in energy recovery in power plants. This research wa...

This study validated the CO2 distribution predicted by a computational fluid dynamics model considering CO2 absorption by photosynthesis in a chamber and greenhouse. The effect of photosynthesis with CO2 emission from a perforated tube remains not fully understood, although previous studies on CO2 distribution in greenhouses have been conducted. Mo...

River waste in Surakarta City primarily consists of biodegradable waste that can be processed by biological processes such as composting. However, there are various kinds of composting application techniques. This, of course, must be adapted to the conditions in Surakarta City. This study aims to conduct a decision analysis on debris processing tec...

Indonesian marine debris of aquatic waste in Jakarta is managed by the UPK of the Water Agency, one of which is the Pluit Employment. Several composting methods can be used and adapted to the available circumstances and needs. The composting process is carried out by utilizing the supply of oxygen, nutrients, water, and temperature control. This st...

Unlike other potentially toxic metals, zinc (Zn) is indispensable to life but also poses environmental risks to aquatic organisms. Aichi Prefecture has the Japan's fourth‐highest discharges of Zn into water bodies. As a major industrial area, it is likely that the Zn fluxes in Aichi's water bodies originate from industrial wastewater. This study ev...

Marine debris is one of the global problems due to human activities. One of the biggest loads of marine debris is in the city of Jakarta, namely the Pluit Emplacement. Emplacement Pluit is a special location for managing marine debris in Jakarta, with the largest burden of marine debris problems discharged from urban areas. This study analyses aqua...

Heavy metal contamination in the urban river has become the most severe problem in the urban environment, especially the zinc (Zn) compound is harmful to the environment at current levels of exposure. This study aims to assess the impact of urbanization and industrialization on Zn pollution in surface sediment at the Umeda River. Triplicate surface...

Solid waste management on Nusa Penida Island is one of the problems in tourism in Bali Province. To deal with this issue, the government has implemented various policies, where the policy that becomes an essential issue is the processing of energy waste. To support this, it is necessary to study the potential of waste characteristics on the island...

One of the contributors to eutrophication is from agricultural wastewater which contained nutrients such as nitrogen and phosphorus. The agricultural industry in Japan has practice greenhouse plantation recently. In this study, the amount of nutrient concentration and load in the wastewater were investigated. Water samples from water supply, soil m...

To clarify the human health risk of inhalation of gaseous elemental mercury (GEM), we measured GEM concentrations in three artisanal small-scale gold mining (ASGM) areas of Palu (Central Sulawesi, 342 000 residents), Muara Aman (Benkulu in Sumatra, about 1000 residents), and Palangka Raya (Central Kalimantan, 236 000 residents). These sites differe...

There are still many people in Jakarta who throw their garbage into the river, resulting Jakarta city never being absent from the problems of river water pollution and flooding. Pesanggrahan River and Grogol River are some of the big river surrounded by high popullation area. All waste originating from the Pesanggrahan River and the Grogol River is...

A stringent environmental quality standard for zinc (Zn) has been enacted by regulators because of its toxicity to aquatic life. This study’s objective was to evaluate the variability of Zn concentrations and fluxes in the baseflow and stormflow and to estimate the contribution of Zn from point and non-point sources. By using high-resolution tempor...

We aimed to assess and observe the accumulation of Cu, Cd, and Hg heavy metals on land and the contamination of plant tissues in Grand Forest Park, Palu, Indonesia, and its surrounding areas. The method used was a mix between survey and investigation, integrating data on research findings from before 2013 to 2016 with data from 2018. The data were...

This research study evaluated the amount of total Zinc in the surface water of Umeda river during rainy event, which is located in southeastern corner of Toyohashi city, Aichi, Japan. The river is comprising of 62% agricultural area while the remaining is urban area and manufacturing zone. Hence, a total of 43 bottles (capacity 1000 ml) water sampl...

Predictive numerical simulation of airflow uniformity in canopy plants could provide a suitable environment for plant growth. A numerical investigation of airflow in a photosynthesis chamber was conducted using the Computational Fluid Dynamics (CFD) model. This research validated the numerical model with measurements performed in an empty bottom op...

Due to the adverse effects of zinc (Zn) on the aquatic organisms, environmental quality standards (EQS) for zinc of 0.03 mg/L in surface water has been enacted in Japan since 2003. However, “zinc elevated sites” persist, including Aichi Prefecture. This study aims to assess the spatial and temporal variability of zinc contamination for 14 months in...

For improving the management of watershed eutrophication, methods for measuring bioavailable phosphorus (BAP) are more important than measurements of total phosphorus (TP). BAP in particulate form (P-BAP) is an important substance that promotes eutrophication, especially during rainy seasons. Only a portion of particulate phosphorus (PP) is taken u...

A numerical simulation was performed to predict the distribution and uniformity of the airflow in a newly developed photosynthesis chamber. It is a semi-closed hanging-type chamber with three exhaust fans placed at the top to maintain airflow. The chamber's bottom (area: 0.55 m²) is fully opened for outside air inflow. For model validation, we meas...

Aichi Prefecture, which has a dense industrial area, is one of the sites in Japan where the levels of zinc are elevated. However, currently, there is no clear evidence of the source of zinc in this prefecture. This study aims to assess zinc concentration and load in a river and identify the main sources of zinc pollution. We conducted a 20‐month su...

Eutrophication is a global environmental issue and has been studied for more than 40 years in Atsumi Bay, Aichi Prefecture, Japan. The distribution of nutrients in watersheds and estuaries is strongly influenced by meteorological factors, especially rainfall. Our observations in summer 2010 found that high river discharges during rainfall altered n...

This study was carried out to determine the concentration of phosphorus in six rivers from agricultural and urban rivers and to compare the bioavailable phosphorus (BAP). Nutrients entering rivers are divided into suspended and dissolved state. In this study, BAP was measured by using ultrasonic extraction method. A 100 L sample was collected from...

Suspended sediments (SS) play a key role as carriers of particulate nutrients which support primary productivity in aquatic systems. In this study, we assessed the relationship between particulate bioavailable phosphorus (PBAP), particulate organic carbon (POC) and particulate organic nitrogen (PON) in rivers flowing through contrasting land use at...

Reduction of atmospheric sulfur (S) deposition and recovery of terrestrial ecosystems from acidification are matters of concerns in Asia. The Lake Ijira catchment (IJR) is located in the downwind region of the Chukyo Industrial Area in central Japan and has historically experienced large-scale deposition of S and nitrogen (N) from the atmosphere. L...

Bioavailable phosphorus (BAP) is a fraction of total phosphorus (TP) that accelerates algae growth in aquatic ecosystems. BAP is comprised of dissolved phosphorus (DP) and a portion of particulate phosphorus (PP). Algal assays and chemical extractions can be applied to determine BAP. However, several constraints such as long extraction time and hig...

Eutrophication in an estuary occurs as an effect of the enrichment of nutrient inputs from rivers. This condition has become one of the most common environmental issues experienced around the globe and especially in Japan. Atsumi Bay is a eutrophic coastal area in Japan. The objective of this research was to analyze the influences of nutrient input...

The Marikina River in the Philippines has been polluted by Payatas landfill leachate, and domestic and agricultural waste. This study monitored the water quality at five stations on the river and two stations on two creeks that discharge to the river to determine the effects of Payatas landfill and to estimate pollution loading. The dissolved oxyge...

This study aims: • To assess the concentration of heavy metals. • To determine if the water is safe for human consumption. This study aims: • To assess the concentration of heavy metals. • To determine if the water is safe for human consumption.

Background and Objective: Tithonia diversifolia (T. diversifolia) compost could be used for reducing the effect of mercury (Hg) poisoning on heavy metal contaminated soil. Land and plants in Poboya Mining, Central Sulawesi, have been contaminated by mercury. This study aims to determine the decreasing activity of Hg²⁺ peanut and water spinach due t...

A study of the Water Quality Index (WQI) of rivers in Penang Island, Malaysia conducted by Universiti Sains Malaysia from October 2012 to January 2013 shows that almost all rivers in Penang Island were slightly polluted or polluted. However, WQI does not clarify each water quality indices, for example nutrients and organic pollutants, that reflect...

The concentration of bioavailable phosphorus (BAP), which is readily available to algae, has been reported to be important to the severity of eutrophication. Because time-consuming conventional methods have constrained sample processing, a rapid method of estimating BAP is required. We investigated an extraction method using 0.1 M NaOH in combinati...

Payatas landfill in Quezon City, Philippines, releases leachate to the Marikina River through a creek. Multivariate statistical techniques were applied to study temporal and spatial variations in water quality of a segment of the Marikina River. The data set included 12 physico-chemical parameters for five monitoring stations over a year. Cluster a...

Eutrophication is a common problem in closed bodies of water areas during the summer. Recent reports have alleged that bioavailable phosphorus (BAP) in particulate forms contributes to eutrophication. However, current methods for quantifying particulate BAP are time-consuming and tedious. Here, we investigated the use of extraction with 0.1 M NaOH...

This study aimed to assess the impact of the traditional gold mine management use of mercury in uncontrolled number on public health and agricultural land. This study used an observational studies method on the three traditional mining locations: Poboya, Sausu, and Dongi-Dongi as the representative locations of the mine area. The data is mercury le...

Poboya is a major small-scale gold-mining area in Central Sulawesi, Indonesia, that has been operating since 2009. About 200–500 kg of mercury is released each day as a result of gold-mining activities over a total area of 7000 ha. We examined mercury contamination by using two types of sample, namely food and human hair. Samples were obtained in P...

Poboya, Central Sulawesi is one of the primary sites used for small-scale gold mining activities in Indonesia. Poboya consumes 200-500 kg of mercury/day by amalgamation. Palu, the capital city of Central Sulawesi, is a city with a population of 0.35 million people and located around 11 km away from the edge of a small-scale gold mining area in Pobo...

Several bioassays and chemical extraction methods have been proposed to quantify bioavailable phosphorus (BAP), but procedural and theoretical limitations have hindered their use. In this paper, we developed a method for P extraction from agricultural soil and suspended sediment by combining ultrasonic treatment with extraction by 0.1 molL-1 NaOH s...

This research is comparative study of gold mining and non-gold mining areas, using four community vulnerability indicators. Vulnerability indicators are exposure degree, contamination rate, chronic, and acute toxicity. Each indicator used different samples, such as wastewater from gold mining process, river water from Tajum river, human hair sample...

While the effluent pollutant loads of nitrogen, phosphorus, and COD from paddy fields are very important basic figures in a wide variety of environmental planning and research tasks, more reliable figures have been required. In this paper, the database of the pollutant load from paddy fields in Japan, established by the authors, is explained and th...

Wando and tamari are water bodies in the floodplain of a river and play an important role in maintaining valuable ecosystems. There are over 100 wando and tamari in the middle and lower basin of the Kiso River. An Acheilognathus longipinnis, Itasenpara Bitterling, which is designated as an endangered species, has been identified in these areas. The...

The mercury concentrations in the atmosphere and in rivers were measured in the Krueng Sabee town Aceh Jaya District in Indonesia where a small-scale gold mining was heavily done on July 2010. The gaseous mercury concentration was measured with the simultaneous use of passive samplers, recently developed for multi-point sampling, and active sampler...

We investigated the availability of different forms of particulate soil phosphorus (P) to Microcystis aeruginosa by sequential extraction and bioassay. We cultured M. aeruginosa in media containing, as the sole source of P, soils sequentially extracted with 1 M NH4Cl, 0.11 M bicarbonate dithionite, 1 M NaOH, and 0.5 M HCl. Analyses of chlorophyll-a...

Typhoon No. 14 that hit Japan on 30th October 2010 brought a huge water mass that increased the water volume and nutrient into the Atsumi Bay estuary, Japan. The aims of this research were to clarify the impact of a typhoon on the physical properties and nutrient concentrations of Atsumi Bay. This study summarizes the effects of a typhoon on nutrie...

The nutrient loads from the Hamada River were studied extensively to develop a method of estimating reliable nutrient loads to Mikawa Bay from small rivers. In this study, the L-Q equations for the Hamada River were determined by applying the least-squares method to logarithmic and antilogarithmic regression curves based on data of ordinary flow an...

Bioavailable phosphorus has been reported to include not only phosphorus in dissolved form but also the fraction of particulate phosphorus that is readily usable. Here, a chemical extraction scheme in combination with an algal bioassay was conducted to estimate the potential bioavailability of particulate phosphorus in soil collected from a Chinese...

Algal blooms in eutrophic water bodies are controlled by inputs of phosphorus (P) as the growth-limiting nutrient. Runoff particulate P associated with soil from fields often predominates among P fractions. Here, an algal bioassay to investigate the potential bioavailability of particulate P in soil collected from a citrus orchard was conducted. Mi...

To study the relationship between the concentrations of nitrogen in mountain streams, and anthropologic and natural factors, the water chemistry of the mountain streams in the entire Hyogo Prefecture, Japan, were investigated. A thousand mountain streams were investigated between 1998 and 2001. The concentrations of nitrate nitrogen ranged from 2.9...

Rapid industrialization in East Asia is causing adverse effects due to atmospheric deposition in terrestrial and freshwater ecosystems. Decreasing stream pH and alkalinity and increasing NO3 − concentrations were observed throughout the 1990s in the forested Lake Ijira catchment in central Japan. We investigated these changes using data on atmosphe...

A great amount of fertilizer is applied to tea plantation area to improve the quality of the product in Japan. Field surveys on water quality of a small river whose watershed includes tea plantation fields and questionnaire survey to the owners in the area were carried out to make clear the runoff characteristics of nutrients, both nitrogen and pho...

We estimated four methods of calculating loads of nutrients from a citrus orchard in Japan. River water discharge and nutrient loads were examined every week for 2 years and more intensively at the time of one rainfall event. River water level was recorded automatically at 5-minute intervals. Nutrient concentrations and water discharge data obtaine...

From 2004 to 2007 we studied the contamination of the Kahayan and Rungan Rivers in Central Kalimantan, Indonesia, by mercury used in the processing of mined gold. Water, sediments and fish species were collected from both rivers. Total mercury concentration was determined by cold vapor atomic absorption spectrometry (CVAAS). In the Kahayan River an...

The release of pharmaceuticals into the aquatic environment and their occurrence in surface waters has become an increasing concern in recent years. In this study we investigated the occurrence of oxytetracycline (OTC), one of the most widely used veterinary antibiotics, in stream waters in a small catchment area with many livestock farms. OTC was...

Since 1983, the Ministry of the Environment of Japan has conducted nation-wide acid deposition surveys. To investigate the effects of acid deposition on surface water, we used the nonparametric Mann–Kendall test to find temporal trends in pH, alkalinity, and electrical conductivity (EC) in more than 10years of data collected from five lakes and the...

Although advances in water treatment technology have contributed to improved water quality at water treatment plants, treated water is not reaching consumer taps with the same quality. Water quality in service pipes is lower than at the water treatment plants, most likely because rust corrosion particles are generated inside the pipes, accumulated...

Verification of a diffuse pollution model involves comparing results actually observed with those predicted by precise model inputs. Acquisition of precise model inputs is, however, problematic. In particular, when the target catchment is large and substantial estimation uncertainty exists, not only model verification but also prediction is difficu...

To evaluate the role of a dam reservoir in the runoff of pollutant loadings from a forested watershed, the input-output budgets in the Ikuno dam reservoir had been investigated for eight years since 1996. The T-N, T-P, TOC and major ionic species in the bulk precipitation, stream water, and outflow were measured. The residence time calculated by us...

In predicting time-series concentrations of pesticides in river water using diffuse pollution hydrological models, farming schedules (including pesticide application) and pesticide sorption/decomposition rates greatly affect prediction accuracy. For large, basin-scale catchments, precise acquisition of these data is not possible and substantial est...