Robert M. Delinom
Indonesian Institute of Sciences
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Featured researches published by Robert M. Delinom.
Science of The Total Environment | 2008
Yu Umezawa; Takahiro Hosono; Shin-ichi Onodera; Fernando P. Siringan; Somkid Buapeng; Robert M. Delinom; Chikage Yoshimizu; Ichiro Tayasu; Toshi Nagata; Makoto Taniguchi
The status of nitrate (NO(3)(-)), nitrite (NO(2)(-)) and ammonium (NH(4)(+)) contamination in the water systems, and the mechanisms controlling their sources, pathways, and distributions were investigated for the Southeast Asian cities of Metro Manila, Bangkok, and Jakarta. GIS-based monitoring and dual isotope approach (nitrate delta(15)N and delta(18)O) suggested that human waste via severe sewer leakage was the major source of nutrient contaminants in Metro Manila and Jakarta urban areas. Furthermore, the characteristics of the nutrient contamination differed depending on the agricultural land use pattern in the suburban areas: high nitrate contamination was observed in Jakarta (dry fields), and relatively lower nutrients consisting mainly of ammonium were detected in Bangkok (paddy fields). The exponential increase in NO(3)(-)-delta(15)N along with the NO(3)(-) reduction and clear delta(18)O/delta(15)N slopes of NO(3)(-) ( approximately 0.5) indicated the occurrence of denitrification. An anoxic subsurface system associated with the natural geological setting (e.g., the old tidal plain at Bangkok) and artificial pavement coverage served to buffer NO(3)(-) contamination via active denitrification and reduced nitrification. Our results showed that NO(3)(-) and NH(4)(+) contamination of the aquifers in Metro Manila, Bangkok, and Jakarta was not excessive, suggesting low risk of drinking groundwater to human health, at present. However, the increased nitrogen load and increased per capita gross domestic product (GDP) in these developing cities may increase this contamination in the very near future. Continuous monitoring and management of the groundwater system is needed to minimize groundwater pollution in these areas, and this information should be shared among adjacent countries with similar geographic and cultural settings.
Science of The Total Environment | 2008
Shin-ichi Onodera; Mitsuyo Saito; Misa Sawano; Takahiro Hosono; Makoto Taniguchi; Jun Shimada; Yu Umezawa; Rachmat Fajar Lubis; Somkid Buapeng; Robert M. Delinom
Asian megacities have severe pollution problems in both coastal and urban areas. In addition, the groundwater potential has decreased and land subsidence has occurred because of intensive groundwater pumping in urban areas. To prevent the adverse effects of urbanization on groundwater quality, it is necessary to confirm the changes in groundwater flow and contaminant transport caused by urbanization. We examined the effects of urbanization on contaminant transport in groundwater. The research areas were located around Bangkok, Thailand, and Jakarta, Indonesia, cities with populations of approximately 8 and 12 million, respectively. Each metropolitan city is located on a river delta and is adjacent to a bay. We measured the water level and collected water samples at boreholes at multiple depths (100 to 200 m) in 2004 and 2006 in Bangkok and Jakarta, respectively. The current hydraulic potential is below sea level in both cities because of prior excess abstraction of groundwater. As a result, the direction of groundwater flow is now downward in the coastal area. The Cl(-) concentration and delta(18)O distributions in groundwater suggest that the decline in hydraulic potential has caused the intrusion of seawater and shallow groundwater into deep groundwater. Concentrations of Mn and NO3(-)-N in groundwater suggest the intrusion of these contaminants from shallow to deep aquifers with downward groundwater flow and implies an accumulation of contaminants in deep aquifers. Therefore, it is important to recognize the possibility of future contaminant transport with the discharge of deep groundwater into the sea after the recovery of groundwater potential in the coastal areas.
Science of The Total Environment | 2009
Robert M. Delinom; Abdurrahman Assegaf; Hasanuddin Z. Abidin; Makoto Taniguchi; Dadan Suherman; Rachmat Fajar Lubis; Eko Yulianto
This study examines the factors of human activities causing environmental stresses on the subsurface environments in the urban settings of Jakarta. A major objective of this study is to identify the basin geometry and estimate how critical is the degradation of the subsurface environment within the basin, and it covered micro-palaeontology and chemical analyses, the decrease of water level, and GPS data. New data on shallow groundwater quality is provided and the results indicate strong evidence for human activities have influenced the degradation of the Jakarta subsurface environment.
Palaeogeography, Palaeoclimatology, Palaeoecology | 1988
Christian Jouannic; Chi-Trach Hoang; Wahyoe S. Hantoro; Robert M. Delinom
Abstract A Th/U date of 152,000 years obtained from the prominent fifth step, at 44 m elevation, of a flight of 7 well defined raised reef terraces at Cape Namosain, 5 km west of Kupang, allows inference of a preliminary mean uplift rate of 0.3 mm/yr since the last interglacial. Such a slow uplift rate is supported by the observation of numerous large modern reef platforms and of very limited mid-Holocene emergence — if any — throughout the region. Subject to conformation through further dating, this suggests the existence of a more rapid uplift zone in central West Timor, by contrast with the area of Kupang to the west and of northern East Timor and Atauro Island to the east, possibly in relation with the NW-SE seismic tear zone which has been recently pointed out within the subducting plate north of West Timor. One of the main interests in the terraces of Cape Namosain, apart from its neotectonic aspect, resides in the fact that there may be an oppurtunity to define the 180,000 year old paleo-sea level (terrace VIII of Huon Peninsula): based on the geomorphological interpretation of the series, it could correspond here to the fourth or the sixth terrace. Field investigation and dating in that regard are currently in progress. Another Th/U date of 124,000 years, obtained on the lowest emerged terrace (7 m above low tide) in the southeast of the nearby island of Semau, indicates that this second area has been uplifting little during the last 125,000 years. This, together with the observation of tilts and other structural features, leads to the conclusion that the area of the southwest of Kupang is affected by differential uplifts and block-faulting.
Science of The Total Environment | 2011
Takahiro Hosono; Robert M. Delinom; Takanori Nakano; Makoto Kagabu; Jun Shimada
The sources of sulfate in an aquifer system, and its formation/degradation via biogeochemical reactions, were investigated by determining sulfate isotope ratios (δ³⁴S(SO₄) and δ¹⁸O(SO₄) in dissolved sulfate in groundwater from the Jakarta Basin. The groundwater flow paths, water ages, and geochemical features are well known from previous studies, providing a framework for the groundwater chemical and isotopic data, which is supplemented with data for spring water, river water, hot spring water, seawater, detergents, and fertilizers within the basin. The sulfate isotope composition of groundwater samples varied widely from -2.9‰ to +33.4‰ for δ³⁴S(SO₄) and +4.9‰ to +17.8‰ for δ¹⁸O(SO₄) and changed systematically along its flow direction from the mountains north to the coastal area. The groundwater samples were classified into three groups showing (1) relatively low and narrow δ(34)S(SO₄) (+2.3‰ to +7.6‰) with low and varied δ¹⁸O(SO₄) (+4.9‰ to +12.9‰) compositions, (2) high and varied δ³⁴S(SO₄) (+10.2‰ to +33.4‰) with high δ¹⁸O(SO₄) (+12.4‰ to +17.3‰) compositions, and (3) low δ³⁴S(SO₄) (< +6.1‰) with high δ¹⁸O(SO₄) (up to +17.8‰) compositions. These three types of groundwater were observed in the terrestrial unconfined aquifer, the coastal unconfined and confined aquifers, and the terrestrial confined aquifer, respectively. A combination of field measurements, concentrations, and previously determined δ¹⁵N(NO₃) data, showed that the observed isotopic heterogeneity was mainly the result of contributions of pollutants from domestic sewage in the rural area, mixing of seawater sulfate that had experienced previous bacterial sulfate reduction in the coastal area, and isotopic fractionation during the formation of sulfate through bacterial disproportionation of elemental sulfur. Our results clearly support the hypothesis that human impacts are important factors in understanding the sulfur cycle in present-day subsurface environments. A general model of sulfate isotopic evolution along with groundwater flow has rarely been proposed, due to the complicated hydrogeological research setting that causes varied isotope ratios, although its understanding has recently received great attention. This pioneer study on a simple volcanic fan aquifer system with a well-understood groundwater flow mechanism provides a useful model for future studies.
Environmental Earth Sciences | 2013
Rachmat Fajar Lubis; Makoto Yamano; Robert M. Delinom; Sudaryanto Martosuparno; Yasuo Sakura; Shusaku Goto; Akinobu Miyakoshi; Makoto Taniguchi
Urbanization has become one of the domain processes for city development in Indonesia. The results of the extremely high densities of fast growing population have led to negative subsurface environmental impact. Jakarta, as one of the rapidly developed and urbanized cities in Southeast Asia, has become one of the interesting urbanization city to analyze its effects. In Jakarta, the use of groundwater has greatly accelerated conforming to the rise in its population and the development of the industrial sector, which consume a relatively large amount of water. The increase of groundwater exploitation in Jakarta city has already caused a negative impact on these resources. Therefore, an assessment of groundwater trends in the urban area, including their hazard and risk management, is a necessary action. This paper describes the assessment of urban groundwater loading caused by human concentration in Jakarta city. Subsurface heat contamination under the condition of surface warming shows significant effects of urban groundwater loading during the past century in Jakarta city.
IOP Conference Series: Earth and Environmental Science | 2018
Rachmat Fajar Lubis; Robert M. Delinom; Sudaryanto Martosuparno; Hendra Bakti
The water-food nexus is promoted as an approach to look at the linkages between water and food. The articles of Waters Special Issue Water-Energy-Food Nexus in Large Asian River Basins look at the applicability of the nexus approach in different regions and rivers basins in Asia. Citarum River was selected for the case of Indonesia study site of RIHN Water-food Nexus Project with a focus on the Juanda/Jatiluhur dam as the downstream of the three large cascaded reservoirs and river estuary at the Jakarta Bay. As a result, there are a variety of interpretations for the nexus. These include three complementary perspectives that perceive nexus as an analytical approach, governance framework and emerging discourse. Secondly, nexus is a predominantly water-sector driven and water-centered concept. Evaluation of water quality of Citarum River and the increasing demands for water-food nexus revealed the critical status even at present condition that requires strategic decision to modify the water allocation policy to ensure human-environmental sustainability water security.
Marine Research in Indonesia | 2017
Hendra Bakti; Rachmat Fajar Lubis; Robert M. Delinom; Makoto Taniguchi
Submarine groundwater discharge (SGD) is defined as all direct discharge of subsurface fluids into coastal zone. Components of SGD consist of fresh submarine groundwater discharge and the recirculated saline seawater discharge. SGD could act as a pathway for the transport of anthropogenic contaminants and nutrients to coastal waters. Measurement SGD at Carnaval Beach, Ancol, Jakarta was focussed on unconfined groundwater system. The method of quantified used automatic seepage meter for measured of SGD and installed conductivity temperature depth. The average SGD rate was 0.21 mm/min on March 20-31, 2009 consist of 19.05% fresh water, 80.95% recirculated seawater. April 1-23, 2009, the average SGD rate was 0.81 ml/min which consisted of 16.04% fresh water, 83.96% recirculated seawater. SGD fluctuation was opposite with the tide. As a result, submarine groundwater discharge at Jakarta coastal area was defined and can be measured to quantify.
Archive | 2011
Robert M. Delinom
The Greater Jakarta, the capital city of Republic of Indonesia, occupies the northern zone of Java Island and the elevations of this plain vary from 0 to 1,000 m above sea level. Some evident showed that the population influenced the condition of groundwater resources in this megacity as most of them acquire the needed water by groundwater abstraction. It caused a negative impact on these resources itself both quantity and quality. Therefore, the proper groundwater management of this area should be established and the groundwater management should cover the two important aspects, i.e., physical and technical aspects, and social and non technical aspects.
Estuarine Coastal and Shelf Science | 2011
Takahiro Hosono; Chih-Chieh Su; Robert M. Delinom; Yu Umezawa; Tomoyo Toyota; Shinji Kaneko; Makoto Taniguchi