Temporal and Spatial Variations of Inorganic Nitrogen Levels in Surface and Groundwater Around Hanoi, Vietnam

Kurosawa, Kiyoshi; Hai, Do Nguyen; Thanh, Nguyen Huu; Tra, Ho Thi Lam; Ha, Tran Thi Le; Canh, N. T.; Egashira, Kensuke

doi:10.1080/00103620500447025

Cited by 9 publications

(4 citation statements)

References 3 publications

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“…N-NH 4 ), P (P-PO 4 ), and Si (DSi), were calculated at the inlet and the outlet of the five sub-basins on the basis of the water budget as established by Luu et al (2010), (see Fig. 1b, c), and the mean annual concentrations of DSi and P-PO 4 , measured in the field or taken from the literature (Kurosawa et al 2006;Le et al 2005Le et al , 2010IMHE -MONRE 1996-2006Nguyen et al 2005;Trinh et al 2006;Tran et al 2006) Flx ð10 6 kg year À1 Þ ¼ Qm Â Cm Â 3; 600 Â 24 Â 365 10 9…”

Section: Nutrient and Suspended Solid Flux Calculationsmentioning

confidence: 99%

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N, P, Si budgets for the Red River Delta (northern Vietnam): how the delta affects river nutrient delivery to the sea

et al. 2010

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The Red River Delta (RRD) (Vietnam), a region experiencing rapid population growth, industrialization, and economic development, concentrates 54% of the population of the whole Red River watershed in less than 10% of the basin area. Our study aimed at understanding and quantifying the processes by which the delta affects the nutrient fluxes coming from the upstream watershed before they reach the sea. A comprehensive budget of nitrogen (N), phosphorus (P), and silica (Si) fluxes associated with natural and anthropogenic processes in the terrestrial and hydrological system of the delta was established for five sub-basins of the delta for the period 2000-2006, based on official statistical data, available measurements, and our own sampling campaigns and enquiries. The results show that anthropogenic inputs of N and P brought into the delta area are higher than the amounts delivered by the river from the upstream watershed. However, the amounts of these two elements ultimately delivered to the coastal zone from the delta are lower than the amounts carried by the upstream river, showing extremely efficient retention of both the soils and the delta's drainage network. For Si (taking into account both dissolved and amorphous solid forms), the retention is much lower. High retention of N and P and low retention of Si in the delta area have up to now protected the coastal zone from severe eutrophication problems.Electronic supplementary material The online version of this article

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Section: Nutrient and Suspended Solid Flux Calculationsmentioning

confidence: 99%

“…1b). Nutrient concentration in runoff from each land use type was evaluated from direct measurements and from the literature (Kurosawa et al 2006;Wosten et al 2003). Point sources were estimated from population data and industrial census.…”

Section: Budget Of the Hydrological Networkmentioning

confidence: 99%

N, P, Si budgets for the Red River Delta (northern Vietnam): how the delta affects river nutrient delivery to the sea

et al. 2010

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“…This is particularly notable in the DRB (Fig. 1), where rice cultivation constitutes approximately 50% of land use and the majority of the fertilizer used is applied to paddy fields (DARD-Hanoi 2009; DARD-Namdinh 2011; Kurosawa et al 2004;Kurosawa et al 2006). These chemical fertilizers applied within the DRB are the primary sources of N in the Day River (MONRE 2006;Hanh et al 2010).…”

Section: Study Site Descriptionmentioning

confidence: 99%

Stable isotopes as an effective tool for N nutrient source identification in a heavily urbanized and agriculturally intensive tropical lowland basin

et al. 2020

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We present the application of dual stable isotope analyses of NO3 (δ 15 N-NO3 and 18 O-NO3) to provide a comprehensive assessment of the provenance, partitioning, and conversion of nitrate across the Day River Basin (DRB), Vietnam, which is heavily impacted by agriculture and urbanization. Stable isotope compositions of river water 18 O-H2O, in addition to their δ 15 N-NO3 and 18 O-NO3 signatures, were Man scripClick here to access/download;Manuscript;Biogeochemistry_3_final_VNP.doc Click here to ie linked References sampled at 12 locations in the DRB. Sample collection was conducted during three different periods to capture changes in regional weather and agricultural fertilization regimes; April (the dry season and key fertilization period), July (the rainy season and another key fertilization period) and October (the rainy season with no regional fertilization). Ranges of NO3 stable isotopes are -7.1 to +9.2 and -3.9 to +13.2 for 18 O and 15 N, respectively. Interpretation of the stable isotope data characterizes 4 main sources of NO3 in the DRB; (1) nitrified urea fertilizer derived from an intensive agricultural irrigation network, (2) soil and groundwater leaching from within the basin (3) manure and sewage inputs (which is more prevalent in downstream river sections) and ( 4) upstream inflow from the Red River which discharges into the Day River through the Dao River. We applied a mixing model for the DRB consisting of 4 variables, representing these 4 different sources. The partition calculation shows that during the fertilization and rainy period of July, more than 45% of river NO3 is derived from nitrified urea sources.During the other sampling periods (April and October), manure and sewage contribute more than 50% of river NO3 and are derived from the middle portion of the DRB, where the Day River receives domestic wastewater from the Vietnamese capital, Hanoi. Stable isotope data of O and N reveal that nitrification processes are more prevalent in the rainy season than in dry season and that this predominantly takes place in paddy field agricultural zones. In general, data demonstrate that nitrate loss in the DRB is due to denitrification which takes place in polluted stretches of the river and dominates in the dry season. This study highlights that i) domestic waste should be treated prior to its discharge into the Day River and ii) the need for better catchment agricultural fertilization practices as large portions of fertilizer currently discharge into the river, which greatly impacts regional water quality.

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“…[3,4] However, these groundwater sources contain contaminants such as ammonium-nitrogen (NH 4 -N) in concentrations higher than that limits prescribed by the World Health Organization (WHO). Even though the consumption of low levels of NH 4 -N does not have any negative effects on human health, high concentrations can make the water unsuitable for consumption due to bad taste and smell.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the effects of hydrogenotrophic denitrification and anammox on the improvement of the quality of the drinking water supply system

Khanitchaidecha

Koshy

Kamei

et al. 2013

Journal of Environmental Science and Health, Part A

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A drinking water supply system operates at Chyasal (in the Kathmandu Valley, Nepal) for purifying the groundwater that has high levels of ammonium nitrogen (NH4-N). However, high NO3-N concentrations were seen in the water after treatment. To further improve the quality of the drinking water, two types of attached growth reactors were developed for the purification system: (i) a hydrogenotrophic denitrification (HD reactor) and (ii) a concurrent reactor with anammox and hydrogenotrophic denitrification (AnHD reactor). For the HD reactor fed by water containing NO3-N, the denitrification efficiency was high (95-98%) for all NO3-N feed rates (20-40 mg/L). The nitrite-nitrogen (NO2-N) and nitrate-nitrogen (NO3-N) concentrations in the effluent were ∼0.5 mg/L. On the other hand, the AnHD reactor fed with water containing NH4-N and NO2-N was operated under varying flow rates of H2(30-70 mL/min) and intermittent supply periods (1-2 h). The efficiency of the anammox process was found to increase with decreasing H2flow rates or with increasing intermittency of the H2supply, while the efficiency of denitrification decreased under these conditions. For the optimal condition of 1.5 h intermittent H2supply, the anammox and denitrification efficiencies of the AnHD reactor reached 80% and 42%, respectively, while the concentrations of both NH4-N and NO2-N in the effluent were <1.0 mg/L, and no NO3-N was detected. From the experimental results, it is clear that both HD and AnHD reactors can function as efficient and critical units of the water purification system.

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Temporal and Spatial Variations of Inorganic Nitrogen Levels in Surface and Groundwater Around Hanoi, Vietnam

Cited by 9 publications

References 3 publications

N, P, Si budgets for the Red River Delta (northern Vietnam): how the delta affects river nutrient delivery to the sea

N, P, Si budgets for the Red River Delta (northern Vietnam): how the delta affects river nutrient delivery to the sea

Stable isotopes as an effective tool for N nutrient source identification in a heavily urbanized and agriculturally intensive tropical lowland basin

Investigation of the effects of hydrogenotrophic denitrification and anammox on the improvement of the quality of the drinking water supply system

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