Sources and leaching of manganese and iron in the Saigon River Basin, Vietnam

2011 ◽  
Vol 63 (10) ◽  
pp. 2231-2237 ◽  
Author(s):  
Nguyen Thi Van Ha ◽  
Satoshi Takizawa ◽  
Kumiko Oguma ◽  
Nguyen Van Phuoc
Keyword(s):  
Water Quality ◽  
Low Ph ◽  
Ho Chi Minh City ◽  
Viet Nam ◽  
Leaching Tests ◽  
Acid Sulfate Soil ◽  
Release Rates ◽  
Sediment Samples ◽  
High Concentrations ◽  
Fe Reduction

High concentrations of manganese and iron in the Saigon River are major problems for the water supply in Ho Chi Minh City (HCMC), Viet Nam. To identify their sources and leaching processes, we surveyed water quality along the Saigon River and ran batch leaching tests using soil and sediment samples. Two important leaching processes were identified: acidic leaching from acid sulfate soil (ASS) in the middle reaches of the river, and Mn dissolution and Fe reduction from sediments in the downstream reaches. Low pH caused the concurrent release of Fe and Mn from the ASS. In contrast, anoxia caused the release of Fe but not Mn from the sediments, whereas low pH facilitated Mn dissolution. Sediments are a more important source of Mn because of their higher Mn contents (10 times) and release rates (14 times) than those from ASS.

Algal Demand Drives Sediment Phosphorus Release in a Shallow Eutrophic Cove

2019 ◽  
Vol 62 (5) ◽  
pp. 1315-1324
Author(s):  
James A. McCarty
Keyword(s):  
Water Quality ◽  
Shallow Water ◽  
Sediment Core ◽  
Algal Growth ◽  
Phosphorus Release ◽  
Water Bodies ◽  
Release Rates ◽  
Sediment Samples ◽  
P Release ◽  
Core Incubation

Abstract. Algae play an important role in the internal nutrient cycling of shallow lakes and coves. Algae of shallow water bodies have been shown to thrive and even lead to eutrophic conditions despite a lack of measurable quantities of biologically available phosphorus (P) in the water during summer months. To study how sediment P release and algal growth are connected, water and sediment samples were collected in a shallow eutrophic cove on Beaver Lake in northwest Arkansas. Water quality profiles depicting temperature, dissolved oxygen, nutrients, metals, and photic zone chlorophyll-a were collected weekly from 21 May to 10 July 2018 at three points in the cove: one shallow, one at the cove midpoint, and one at the deepest part of the cove. Cove sediment samples were collected at similar points as the water quality samples for equilibrium P concentration (EPCo) analysis, sediment core incubation, and sediment composition. EPCo for the sediments ranged from 0.024 to 0.027 mg L-1. Sediment cores exposed to aerobic conditions typical of shallow areas had P release rates ranging from 1.37 to 2.02 mg m-2 d-1. Concentrations of soluble reactive P (SRP) in the water column from the weekly water quality sampling averaged 0.002 ±0.003 mg L-1, and photic zone SRP concentrations averaged 0.002 ±0.004 mg L-1 for all sampling sites. The chlorophyll-a concentration increased from 10 to 40 µg L-1 during the period from 21 May to 25 June. When SRP << EPCo, conditions favor the release of SRP from sediments to the overlying water. This was confirmed with the aerobic sediment core incubation in which algal demand was controlled using dark conditions and the release rates were >1.37 mg L-1 d-1. Core aerobic release rates and EPCo conditions both confirmed the release of P under aerobic conditions; however, it appears that algal demand sustained low SRP conditions. This created a nutrient cycle in which algae imposed a nutrient gradient favoring P release by keeping SRP conditions below the EPCo. This study indicates that algal growth potential in shallow water bodies is not limited by SRP concentrations measured within the water column. Studies of shallow water bodies with low SRP concentrations and high productivity should look to the sediments as a source of P to fuel algal growth. Finally, these findings suggest that coves play an integral part in algal production and should not be overlooked when determining the overall P budget for a lake or reservoir. Keywords: Aerobic phosphorus release, Equilibrium phosphorus concentration, Sediment core incubation.

PEUBAH KUALITAS AIR YANG MEMPENGARUHI PERTUMBUHAN RUMPUT LAUT (Gracilaria verrucosa) DI TAMBAK TANAH SULFAT MASAM KECAMATAN ANGKONA KABUPATEN LUWU TIMUR PROVINSI SULAWESI SELATAN

2009 ◽  
Vol 4 (1) ◽  
pp. 125
Author(s):  
Akhmad Mustafa ◽  
Rachmansyah Rachmansyah ◽  
Dody Dharmawan Trijuno ◽  
Ruslaini Ruslaini
Keyword(s):  
Water Quality ◽  
Growth Rate ◽  
Ammonium Phosphate ◽  
Gracilaria Verrucosa ◽  
Acid Sulfate Soils ◽  
Acid Sulfate Soil ◽  
Acid Sulfate ◽  
Independent Variables ◽  
Water Quality Variables ◽  
Sulfate Soils

Rumput laut (Gracilaria verrucosa) telah dibudidayakan di tambak tanah sulfat masam dengan kualitas dan kuantitas produksi yang relatif tinggi. Oleh karena itu, dilakukan penelitian yang bertujuan untuk mengetahui peubah kualitas air yang mempengaruhi laju pertumbuhan rumput laut di tambak tanah sulfat masam Kecamatan Angkona Kabupaten Luwu Timur Provinsi Sulawesi Selatan. Pemeliharaan rumput laut dilakukan di 30 petak tambak  terpilih selama 6 minggu. Bibit rumput laut dengan bobot 100 g basah ditebar dalam hapa berukuran 1,0 m x 1,0 m x 1,2 m. Peubah tidak bebas yang diamati adalah laju pertumbuhan relatif, sedangkan peubah bebas adalah peubah kualitas air yang meliputi: intensitas cahaya, salinitas, suhu, pH, karbondioksida, nitrat, amonium, fosfat, dan besi. Analisis regresi berganda digunakan untuk menentukan peubah bebas yang dapat digunakan untuk memprediksi peubah tidak bebas. Hasil penelitian menunjukkan bahwa laju pertumbuhan relatif rumput laut di tambak tanah sulfat masam berkisar antara 1,52% dan 3,63%/hari dengan rata-rata 2,88% ± 0,56%/hari. Di antara 9 peubah kualitas air yang diamati ternyata hanya 5 peubah kualitas air yaitu: nitrat, salinitas, amonium, besi, dan fosfat yang mempengaruhi pertumbuhan rumput laut secara nyata. Untuk meningkatkan pertumbuhan rumput laut di tambak tanah sulfat masam Kecamatan Angkona Kabupaten Luwu Timur dapat dilakukan dengan pemberian pupuk yang mengandung nitrogen untuk meningkatkan kandungan amonium dan nitrat serta pemberian pupuk yang mengandung fosfor untuk meningkatkan kandungan fosfat sampai pada nilai tertentu, melakukan remediasi untuk menurunkan kandungan besi serta memelihara rumput laut pada salinitas air yang lebih tinggi, tetapi tidak melebihi 30 ppt.Seaweed (Gracilaria verrucosa) has been cultivated in acid sulfate soil-affected ponds with relatively high quality and quantity of seaweed production. A research has been conducted to study water quality variables that influence the growth of seaweed in acid sulfate soil-affected ponds of Angkona Sub-district East Luwu Regency South Sulawesi Province. Cultivation of seaweed was done for six weeks in 30 selected brackishwater ponds. Seeds of seaweed with weight of 100 g were stocked in hapa sized 1.0 m x 1.0 m x 1.2 m. Dependent variable that was observed was specific growth rate, whereas independent variables were water quality variables including light intensity, salinity, temperature, pH, carbondioxide, nitrate, ammonium, phosphate, and iron. Analyses of multiple regressions were used to determine the independent variables which could be used to predict the dependent variable. Research result indicated that relative growth rate of seaweed in acid sulfate soils-affected brackishwater ponds ranged from 1.52% to 3.63%/day with 2.88% ± 0.56%/day in average. Among nine observed water quality variables, only five variables namely: nitrate, salinity, ammonium, phosphate and iron influence significantly on the growth of seaweed in acid sulfate soils-affected brackishwater ponds. The growth of seaweed in acid sulfate soils-affected brackishwater ponds of Angkona District East Luwu Regency, can be improved by using nitrogen-based fertilizers to increase ammonium and nitrate contents and also fertilizers which contain phosphorus to improve phosphate content to a certain level. Pond remediation to decrease iron content and also rearing seaweed at higher salinity (but less than 30 ppt) can also be alternatives to increase the growth of seaweed.

Problems and practical experiences during refilling of the Kerspe-Talsperre under unfavourable climatic conditions

1998 ◽  
Vol 37 (2) ◽  
pp. 145-152 ◽  
Author(s):  
A. E. Nienhüser ◽  
P. Braches
Keyword(s):  
Water Quality ◽  
Early Summer ◽  
Climatic Conditions ◽  
Oxygen Deficit ◽  
Light Limitation ◽  
Raw Water ◽  
Artificial Mixing ◽  
Poor Water Quality ◽  
High Concentrations ◽  
Practical Experiences

Refilling of the Kerspe-Talsperre reservoir after restoration of the dam caused severe problems in water quality and supply due to a long-lasting ice-cover period and minimal precipitation. Unusually short spring overturn, high algal mass in spring and certainly the overflooding of the sediment, which had not been removed, caused a tremendous oxygen deficit in early summer. The whole hypolimnion turned anoxic and even in the metalimnion oxygen declined to a minimum. Manganese and iron reached high concentrations. Despite the poor water quality, raw water was urgently needed for the water supply and was pumped from the epilimnion during the clear water phase and in July when algal biomass was low. In the middle of August holomixis was induced artificially in order to improve water quality. The decline in algal production during and after artificial mixing was probably caused by light limitation of the algae.

scholarly journals Spatial Variation of Water Chemistry in Aries River Catchment Western Romania

2021 ◽  
Vol 11 (14) ◽  
pp. 6592
Author(s):  
Ana Moldovan ◽  
Maria-Alexandra Hoaghia ◽  
Anamaria Iulia Török ◽  
Marius Roman ◽  
Ionut Cornel Mirea ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Water Quality ◽  
Water Chemistry ◽  
Water Samples ◽  
Mine Drainage ◽  
Pollution Indices ◽  
Mining Activities ◽  
River Catchment ◽  
High Concentrations ◽  
The Impact

This study aims to investigate the quality and vulnerability of surface water (Aries River catchment) in order to identify the impact of past mining activities. For this purpose, the pollution and water quality indices, Piper and Durov plots, as well vulnerability modeling maps were used. The obtained results indicate that the water samples were contaminated with As, Fe, Mn, Pb and have relatively high concentrations of SO42−, HCO3−, TDS, Ca, K, Mg and high values for the electrical conductivity. Possible sources of the high content of chemicals could be the natural processes or the inputs of the mine drainage. Generally, according to the pollution indices, which were correlated to high concentrations of heavy metals, especially with Pb, Fe and Mn, the water samples were characterized by heavy metals pollution. The water quality index classified the studied water samples into five different classes of quality, namely: unsuitable for drinking, poor, medium, good and excellent quality. Similarly, medium, high and very high vulnerability classes were observed. The Durov and Piper plots classified the waters into Mg-HCO3− and Ca-Cl− types. The past and present mining activities clearly change the water chemistry and alter the quality of the Aries River, with the water requiring specific treatments before use.

scholarly journals Effect of Maritime Traffic on Water Quality Parameters in Santa Marta, Colombia

2021 ◽  
Vol 9 (5) ◽  
pp. 474
Author(s):  
René Rodríguez-Grimón ◽  
Nestor Hernando Campos ◽  
Ítalo Braga Castro
Keyword(s):  
Water Quality ◽  
Petroleum Hydrocarbons ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Maritime Traffic ◽  
Natural Park ◽  
High Concentrations ◽  
The Impact ◽  
The Relationship ◽  
Multiple Chemical

Since 2013, there has been an increase (>23%) in naval traffic using maritime routes and ports on the coastal fringe of Santa Marta, Colombia. Of major concern, and described by several studies, is the relationship between maritime traffic and coastal contamination. This study proposed a maritime traffic indicator considering the simultaneous effects of several relevant measurements of water quality parameters to estimate the impact of naval activity. The approach involved developing a model including the number of vessels, hull length, and permanence time in berths. In addition, water quality variables, considering climatic seasons, were used to verify association with maritime traffic and touristic activities. The high concentrations of total coliforms (TC) and dissolved/dispersed petroleum hydrocarbons in chrysene equivalents (DDPH) reported by the International Marina of Santa Marta (SM) were affected by the local anthropic activities, including tourism, naval traffic, and urban wastewater discharges. Moreover, our results suggest the occurrence of multiple chemical impacts within Tayrona National Natural Park (PNNT) affecting conservation goals. The estimation of the maritime traffic indicator proposed in this study may be an easy and more complete tool for future studies evaluating the impact of naval activities on environmental quality.

scholarly journals Uncovering prevalence of pangolin consumption using a technique for investigating sensitive behaviour

Oryx ◽  
2021 ◽  
pp. 1-9
Author(s):  
Alegria Olmedo ◽  
Diogo Veríssimo ◽  
E.J. Milner-Gulland ◽  
Amy Hinsley ◽  
Huong Thi Thu Dao ◽  
...  
Keyword(s):  
Representative Sample ◽  
Ho Chi Minh City ◽  
Viet Nam ◽  
Rice Wine ◽  
Population Declines ◽  
Demographic Groups ◽  
Prevalence Estimates ◽  
The 1960S ◽  
Local Use ◽  
Estimate Prevalence

Abstract Pangolins have been exploited throughout history but evidence points to population declines across parts of their ranges since the 1960s, especially in Asia. This is the result of overexploitation for local use and international trade and trafficking of their derivatives. The prevalence of the consumption of pangolin products has been estimated for different localities in Viet Nam but, considering that national legislation prohibits the purchase of pangolin products, previous research has not accounted for the potential for biased responses. In this study, we treat pangolin consumption as a sensitive behaviour and estimate consumption prevalence of pangolin meat, scales and wine (a whole pangolin or pangolin parts or fluids soaked or mixed in rice wine) in Ho Chi Minh City using a specialized questioning method, the unmatched count technique. We also characterize the demographics of consumers. Our results suggest there is active consumption of all three pangolin products, with a best-estimate prevalence of 7% of a representative sample of Ho Chi Minh City residents for pangolin meat, 10% for scales and 6% for wine. Our prevalence estimates exceed estimates from direct questions, providing evidence for the sensitivity of pangolin consumption. We compared our analysis of consumer characteristics with existing profiles of pangolin consumers and found substantial differences, suggesting that consumption occurs among broader demographic groups than previously described. Our findings suggest that efforts to reduce demand for pangolin consumption in Viet Nam should focus on a broader range of consumers than previously identified.

scholarly journals Dissolved organic nutrients at the interface of fresh and marine waters: flow regime changes, biogeochemical cascades and picocyanobacterial blooms—the example of Florida Bay, USA

2021 ◽  
Author(s):  
Patricia M. Glibert ◽  
Cynthia A. Heil ◽  
Christopher J. Madden ◽  
Stephen P. Kelly
Keyword(s):  
Water Quality ◽  
Anthropogenic Activities ◽  
Florida Bay ◽  
Climate Conditions ◽  
Regime Changes ◽  
Physico Chemical ◽  
Organic Nutrients ◽  
High Concentrations ◽  
Chemical Conditions ◽  
Favorable Conditions

AbstractThe availability of dissolved inorganic and organic nutrients and their transformations along the fresh to marine continuum are being modified by various natural and anthropogenic activities and climate-related changes. Subtropical central and eastern Florida Bay, located at the southern end of the Florida peninsula, is classically considered to have inorganic nutrient conditions that are in higher-than-Redfield ratio proportions, and high levels of organic and chemically-reduced forms of nitrogen. However, salinity, pH and nutrients, both organic and inorganic, change with changes in freshwater flows to the bay. Here, using a time series of water quality and physico-chemical conditions from 2009 to 2019, the impacts of distinct changes in managed flow, drought, El Niño-related increases in precipitation, and intensive storms and hurricanes are explored with respect to changes in water quality and resulting ecosystem effects, with a focus on understanding why picocyanobacterial blooms formed when they did. Drought produced hyper-salinity conditions that were associated with a seagrass die-off. Years later, increases in precipitation resulting from intensive storms and a hurricane were associated with high loads of organic nutrients, and declines in pH, likely due to high organic acid input and decaying organic matter, collectively leading to physiologically favorable conditions for growth of the picocyanobacterium, Synechococcus spp. These conditions, including very high concentrations of NH4+, were likely inhibiting for seagrass recovery and for growth of competing phytoplankton or their grazers. Given projected future climate conditions, and anticipated cycles of drought and intensive storms, the likelihood of future seagrass die-offs and picocyanobacterial blooms is high.

scholarly journals Implementation of GINA guidelines in Ho Chi Minh City: a model for Viet Nam

2012 ◽  
Vol 2 (4) ◽  
pp. 181-185
Author(s):  
N. V. Tho ◽  
H. T. H. Loan ◽  
N. T. P. Thao ◽  
N. T. T. Dung ◽  
L. T. T. Lan
Keyword(s):  
Ho Chi Minh City ◽  
Viet Nam ◽  
Gina Guidelines

Taking the pulse of Mother Ganga - Revealing the visible and invisible water pollution crisis along the Ganges River

2021 ◽  
Author(s):  
Stefan Krause ◽  
Keyword(s):  
Water Pollution ◽  
Water Quality ◽  
Land Use ◽  
Surface Water ◽  
River Network ◽  
Ganges River ◽  
Sediment Samples ◽  
Water And Sediment ◽  
The Ganges ◽  
Water And Sediment Samples

<p>It is probably hard to overestimate the significance of the River Ganges for its spiritual, cultural and religious importance. As the worlds’ most populated river basin and a major water resource for the 400 million people inhabiting its catchment, the Ganges represents one of the most complex and stressed river systems globally. This makes the understanding and management of its water quality an act of humanitarian and geopolitical relevance. Water quality along the Ganges is critically impacted by multiple stressors, including agricultural, industrial and domestic pollution inputs, a lack and failure of water and sanitation infrastructure, increasing water demands in areas of intense population growth and migration, as well as the severe implications of land use and climate change. Some aspects of water pollution are readily visualised as the river network evolves, whilst others contribute to an invisible water crisis (Worldbank, 2019) that affects the life and health of hundreds of millions of people.</p><p>We report the findings of a large collaborative study to monitor the evolution of water pollution along the 2500 km length of the Ganges river and its major tributaries that was carried out over a six-week period in Nov/Dec 2019 by three teams of more than 30 international researchers from 10 institutions. Surface water and sediment were sampled from more than 80 locations along the river and analysed for organic contaminants, nutrients, metals, pathogen indicators, microbial activity and diversity as well as microplastics, integrating in-situ fluorescence and UV absorbance optical sensor technologies with laboratory sample preparation and analyses. Water and sediment samples were analysed to identify the co-existence of pollution hotspots, quantify their spatial footprint and identify potential source areas, dilution, connectivity and thus, derive understanding of the interactions between proximal and distal of sources solute and particulate pollutants.</p><p>Our results reveal the co-existence of distinct pollution hotspots for several contaminants that can be linked to population density and land use in the proximity of sampling sites as well as the contributing catchment area. While some pollution hotspots were characterised by increased concentrations of most contaminant groups, several hotspots of specific pollutants (e.g., microplastics) were identified that could be linked to specific cultural and religious activities. Interestingly, the downstream footprint of specific pollution hotspots from contamination sources along the main stem of the Ganges or through major tributaries varied between contaminants, with generally no significant downstream accumulation emerging in water pollution levels, bearing significant implications for the spatial reach and legacy of pollution hotspots. Furthermore, the comparison of the downstream evolution of multi-pollution profiles between surface water and sediment samples support interpretations of the role of in-stream fate and transport processes in comparison to patterns of pollution source zone activations across the channel. In reporting the development of this multi-dimensional pollution dataset, we intend to stimulate a discussion on the usefulness of large river network surveys to better understand the relative contributions, footprints and impacts of variable pollution sources and how this information can be used for integrated approaches in water resources and pollution management.</p>

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