Publications by authors named "Nguyen Thanh-Nho"

8 Publications

  • Page 1 of 1

Respective contribution of urban wastewater and mangroves on nutrient dynamics in a tropical estuary during the monsoon season.

Mar Pollut Bull 2020 Nov 17;160:111652. Epub 2020 Sep 17.

Faculty of Fisheries and Aquatic Resources, Mae Jo University, Chiang Mai, Thailand.

Estuaries of Southeast Asia are increasingly impacted by land-cover changes and pollution. Here, our research objectives were to (1) determine the origins of nutrient loads along the Can Gio estuary (Vietnam) and (2) identify the processes that affect the nutrient pools during the monsoon. We constructed four 24-h time-series along the salinity gradient measuring nutrient concentrations and stable isotopes values. In the upper estuary, urban effluents from Ho Chi Minh City were the main input of nutrients, leading to dissolved oxygen saturation <20%. In the lower estuary, ammonium and nitrite concentration peaks were explained by mangrove export. No contribution from aquaculture was detected, as it represents <0.01% of the total river discharge. Along the salinity gradient, nutrient inputs were rapidly consumed, potentially by phytoplankton while nitrate dual-stable isotopes indicated that nitrification occurred. Thus, even in a large and productive estuary, urban wastewater can affect nutrient dynamics with potentially important ecological risks.
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http://dx.doi.org/10.1016/j.marpolbul.2020.111652DOI Listing
November 2020

Sedimentological and geochemical data in bed sediments from a tropical river-estuary system impacted by a developing megacity, Ho Chi Minh City - Vietnam.

Data Brief 2020 Aug 27;31:105938. Epub 2020 Jun 27.

CARE, Ho Chi Minh City University of Technology, VNU-HCM, Viet Nam.

Sedimentological and geochemical data were obtained for bed sediments from a tropical estuary environment in Vietnam in October 2014, January 2016, and November 2016. The data include grain-size distribution, percentage of clay, silt and sand, percentage of organic matter, concentration of total particulate phosphorus (TPP), concentration of particulate inorganic phosphorus (PIP), concentration of particulate organic phosphorus (POP), percentage of total nitrogen (TN), percentage of total carbon (TC), trace metals concentrations (V, Cr, Co, Ni, Cu, Zn, As, Mo, Cd, Pb) and major elements (Al, Fe, Mn). Geochemical indexes (Enrichment factor EF and Geo-accumulation Index I-geo) and sediment quality guideline (mean Effect Range Median quotients) were calculated.
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http://dx.doi.org/10.1016/j.dib.2020.105938DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7339034PMC
August 2020

Fatty acids, C and N dynamics and stable isotope ratios during experimental degradation of shrimp pond effluents in mangrove water.

Mar Environ Res 2019 Sep 26;150:104751. Epub 2019 Jun 26.

BOREA Biologie des Organismes et Ecosystèmes Aquatiques, UMR 7208 MNHN CNRS SU UA UCN IRD 207, Muséum National d'Histoire Naturelle, 75005, Paris, France.

Intensive shrimp farming generates high loads of wastewaters that are released along tropical coastlines with potential impacts on the ecosystems. In this study, we used an experimental approach to analyze the behavior of shrimp pond effluents released in the Can Gio mangrove waterways (Southern Vietnam). We incubated shrimp pond effluents (EF), river water (RV), and a mixture of both (MI; 90% RV + 10% EF) in a dark room and measured fatty acid (FA) compositions, C and N concentrations and stable isotopes ratios (δC and δN) of suspended particulate matter during 16 days. Fatty acid concentrations rapidly decreased in EF with a 50% loss of FA during the first 24 h of the experiment and a 75% loss after 4 days of incubation. Proportions of the FA 18:1ω7 increased in MI during incubation, suggesting that this FA may be used as a tracer of anthropogenic substances release in marine environments.
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http://dx.doi.org/10.1016/j.marenvres.2019.104751DOI Listing
September 2019

Bioaccumulation of some trace elements in tropical mangrove plants and snails (Can Gio, Vietnam).

Environ Pollut 2019 May 25;248:635-645. Epub 2019 Feb 25.

Faculty of Chemical Engineering and Food Technology, Nguyen Tat Thanh University, Viet Nam.

Mangrove sediments can store high amount of pollutants that can be more or less bioavailable depending on environmental conditions. When in available forms, these elements can be subject to an uptake by mangrove biota, and can thus become a problem for human health. The main objective of this study was to assess the distribution of some trace elements (Fe, Mn, Co, Ni, Cr, As, and Cu) in tissues of different plants and snails in a tropical mangrove (Can Gio mangrove Biosphere Reserve) developing downstream a megacity (Ho Chi Minh City, Vietnam). In addition, we were interested in the relationships between mangrove habitats, sediment quality and bioaccumulation in the different tissues studied. Roots and leaves of main mangrove trees (Avicennia alba and Rhizophora apiculata) were collected, as well as different snail species: Chicoreus capucinus, Littoraria melanostoma, Cerithidea obtusa, Nerita articulata. Trace elements concentrations in the different tissues were determined by ICP-MS after digestion with concentrated HNO and HO. Concentrations differed between stands and tissues, showing the influence of sediment geochemistry, species specific requirements, and eventually adaptation abilities. Regarding plants tissues, the formation of iron plaque on roots may play a key role in preventing Fe and As translocation to the aerial parts of the mangrove trees. Mn presented higher concentrations in the leaves than in the roots, possibly because of physiological requirements. Non-essential elements (Ni, Cr and Co) showed low bioconcentration factors (BCF) in both roots and leaves, probably resulting from their low bioavailability in sediments. Regarding snails, essential elements (Fe, Mn, and Cu) were the dominant ones in their tissues. Most of snails were "macroconcentrators" for Cu, with BCF values reaching up to 42.8 for Cerithidea obtusa. We suggest that high quantity of As in all snails may result from its high bioavailability and from their ability to metabolize As.
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http://dx.doi.org/10.1016/j.envpol.2019.02.041DOI Listing
May 2019

Metals geochemistry and ecological risk assessment in a tropical mangrove (Can Gio, Vietnam).

Chemosphere 2019 Mar 30;219:365-382. Epub 2018 Nov 30.

Department of Analytical Chemistry, Faculty of Chemistry, University of Science, Vietnam National University, Ho Chi Minh City, Viet Nam; Faculty of Chemical Engineering and Food Technology, Nguyen Tat Thanh University, Viet Nam.

Mangrove sediments act as natural biogeochemical reactors, modifying metals partitioning after their deposition. The objectives of the present study were: to determine distribution and partitioning of metals (Fe, Mn, Ni, Cr, Cu, Co and As) in sediments and pore-waters of Can Gio Mangrove; and to assess their ecological risks based on Risk Assessment Code. Three cores were collected within a mudflat, beneath Avicennia alba and Rhizophora apiculata stands. We suggest that most metals had a natural origin, being deposited in the mangrove mainly as oxyhydroxides derived from the upstream lateritic soils. This hypothesis could be supported by the high proportion of metals in the residual fraction (mean values (%): 71.9, 30.7, 80.7, 80.9, 67.9, 53.4 and 66.5 for Fe, Mn, Ni, Cr, Cu, Co, and As respectively, in the mudflat). The enrichment of mangrove-derived organic matter from the mudflat to the Rhizophora stand (i.e. up to 4.6% of TOC) played a key role in controlling metals partitioning. We suggest that dissolution of Fe and Mn oxyhydroxides in reducing condition during decomposition of organic matter may be a major source of dissolved metals in pore-waters. Only Mn exhibited a potential high risk to the ecosystem. Most metals stocks in the sediments were higher in the Avicennia stand than the Rhizophora stand, possibly because of enhanced dissolution of metal bearing phases beneath later one. In a context of enhanced mangrove forests destruction, this study provides insights on the effects of perturbation and oxidation of sediments on metal release to the environment.
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http://dx.doi.org/10.1016/j.chemosphere.2018.11.163DOI Listing
March 2019

Variability of CO emissions during the rearing cycle of a semi-intensive shrimp farm in a mangrove coastal zone (New Caledonia).

Mar Pollut Bull 2018 Apr 22;129(1):194-206. Epub 2018 Feb 22.

IMPMC, Institut de Recherche pour le Développement (IRD), UPMC, CNRS, MNHN, Noumea, New Caledonia; University of Sciences of Ho Chi Minh City, Analytical Chemistry Department, 225 Nguyen Van Cu, District 5, Ho Chi Minh City, Viet Nam. Electronic address:

In New Caledonia, shrimp ponds are built not on cleared mangroves but on salt flats behind the mangroves. The objectives of this study were to determine the variability of CO fluxes from a semi-intensive shrimp pond during active and non-active periods of the farm and to determine the carbon dynamics from the upstream tidal creek to the downstream creek, which receives the farm's effluents. CO emissions from the active pond were estimated at 11.1 ± 5.26 mmol CO m d. By modifying the hydrodynamics of the creeks, farm practices also influenced CO emissions from both the upstream and downstream creeks. After tillage, all the organic carbon deposited at the pond bottom during the active period was mineralized, resulting in CO emissions to the atmosphere estimated at 7.9 TCO ha. Therefore, shrimp farming is an anthropogenic source of CO to the atmosphere, but suitable and optimized rearing practices limit these emissions.
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http://dx.doi.org/10.1016/j.marpolbul.2018.02.025DOI Listing
April 2018

Trace metals partitioning between particulate and dissolved phases along a tropical mangrove estuary (Can Gio, Vietnam).

Chemosphere 2018 Apr 30;196:311-322. Epub 2017 Dec 30.

Department of Analytical Chemistry, Faculty of Chemistry, University of Science, Vietnam National University, Ho Chi Minh City, Viet Nam; IMPMC, Institut de Recherche pour le Développement (IRD), UPMC, CNRS, MNHN, Noumea, New Caledonia, France.

Mangroves can be considered as biogeochemical reactors along (sub)tropical coastlines, acting both as sinks or sources for trace metals depending on environmental factors. In this study, we characterized the role of a mangrove estuary, developing downstream a densely populated megacity (Ho Chi Minh City, Vietnam), on the fate and partitioning of trace metals. Surface water and suspended particulate matter were collected at four sites along the estuarine salinity gradient during 24 h cycling in dry and rainy seasons. Salinity, pH, DO, TSS, POC, DOC, dissolved and particulate Fe, Mn, Cr, As, Cu, Ni, Co and Pb were measured. TSS was the main trace metals carrier during their transit in the estuary. However, TSS variations did not explain the whole variability of metals distribution. Mn, Cr and As were highly reactive metals while the other metals (Fe, Ni, Cu, Co and Pb) presented stable log K values along the estuary. Organic matter dynamic appeared to play a key role in metals fractioning. Its decomposition during water transit in the estuary induced metal desorption, especially for Cr and As. Conversely, dissolved Mn concentrations decreased along the estuary, which was suggested to result from Mn oxidative precipitation onto solid phase due to oxidation and pH changes. Extra sources as pore-water release, runoff from adjacent soils, or aquaculture effluents were suggested to be involved in trace metal dynamic in this estuary. In addition, the monsoon increased metal loads, notably dissolved and particulate Fe, Cr, Ni and Pb.
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http://dx.doi.org/10.1016/j.chemosphere.2017.12.189DOI Listing
April 2018

Spatial variation and risk assessment of trace metals in water and sediment of the Mekong Delta.

Chemosphere 2017 Jul 27;179:367-378. Epub 2017 Mar 27.

Faculty of Environment, HCMUT, Ho Chi Minh City, Viet Nam.

The Mekong Delta, is home to 17 million inhabitants and faces numerous challenges relating to climate change, environmental degradation and water issues. In this study, we assess trace metals concentrations (Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Hg, Pb) in the water, suspended particulate matter and surface sediments of the Tien River, the Northern branch of the Mekong Delta, during both dry and rainy seasons. Metal concentrations in the dissolved and suspended particle phases remain in the low concentration range of the main Asian Tropical River. During transportation in the riverine part, we evidenced that V, Cr, Co, As and Pb are dominant in the particulate phase while Mo, Ni and Cu dominate in the dissolved fraction. In the salinity gradient, dissolved U, V, Mo exhibit conservative behaviour while Ni, Cu, As, Co and Cd showed additive behaviour suggesting desorption processes. In the surface sediment, metal concentrations are controlled by the particle-size, POC contents and Fe, Al and Mn - oxy(hydr)oxides. Calculated Enrichment Factor and Geoaccumulation Index evidenced As enrichment while the calculated mean effect range median quotients evidenced a low to medium ecotoxicological potential effects range in the surface sediments.
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http://dx.doi.org/10.1016/j.chemosphere.2017.03.105DOI Listing
July 2017