The impact of calcium-rich diamond mining effluent on downstream cladoceran communities in softwater lakes of the Northwest Territories, Canada

2018 ◽  
Vol 75 (12) ◽  
pp. 2221-2232 ◽  
Author(s):  
Katherine Griffiths ◽  
Joshua Thienpont ◽  
Adam Jeziorski ◽  
John P. Smol

Effluent from diamond mining operations rich in calcium (Ca) has transformed softwater tundra lakes in the Northwest Territories, Canada. Lakes downstream of the Dominion Diamond Corporation Ekati Mine have experienced marked changes in water chemistry and cladoceran community composition since establishment of the mine in 1998. The greatest changes have occurred at the sites closest to the effluent discharge, with [Ca] increasing from <1 to >30 mg·L−1 and corresponding increases in pH from <7 to >8. A split was identified in the cladoceran communities with Holopedium glacialis (a jelly-clad cladoceran tolerant of low [Ca]) generally dominating the cladoceran community at [Ca] < 2.5 mg·L−1, while in impacted lakes with [Ca] ≥ 2.5 mg·L−1, Daphnia longiremis and Daphnia middendorffiana (taxa with higher [Ca] requirements) were often dominant. In contrast, the three study lakes that did not receive mining effluent maintained stable and low [Ca] (mean [Ca] = 0.66 ± 0.06 mg·L−1 (SD)) throughout the monitoring period and have not experienced directional shifts in their cladoceran communities.

2020 ◽  
Vol 9 (2) ◽  
pp. 1-22
Author(s):  
Phetole P Ramollo

The study aimed to assess the impact of alluvial diamond mining on macroinvertebrate community composition at four selected sites in lower Vaal River in 2016 with the application of the South African Scoring System 5 (SASS5). Macroinvertebrates and physico-chemical water parameters such as pH, turbidity, electrical conductivity and dissolved oxygen were measured seasonally. Turbidity levels were high 5.98.0±0.63 NTU but never exceeded the water quality guidelines of aquaculture, whilst pH values did not vary much and were generally alkaline throughout the study. The macroinvertebrate community structure varied at all sites during the study period. Site 4 was the most impacted site dominated by the more tolerant macroinvertebrates such as Simuliidae, Baetidae and Gyrinidae. The study concludes that although alluvial diamond mining had a negative impact on macroinvertebrate community in the short-term period, they appeared to re-establish quickly once the mining operations stopped.


Ecotoxicology ◽  
2013 ◽  
Vol 22 (8) ◽  
pp. 1186-1199 ◽  
Author(s):  
Olivier Herlory ◽  
Jean-Marc Bonzom ◽  
Rodolphe Gilbin ◽  
Sandrine Frelon ◽  
Stéphanie Fayolle ◽  
...  

2021 ◽  
Vol 11 (14) ◽  
pp. 6592
Author(s):  
Ana Moldovan ◽  
Maria-Alexandra Hoaghia ◽  
Anamaria Iulia Török ◽  
Marius Roman ◽  
Ionut Cornel Mirea ◽  
...  

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.


Author(s):  
Zuhair AlYousef ◽  
Subhash Ayirala ◽  
Majed Almubarak ◽  
Dongkyu Cha

AbstractGenerating strong and stable foam is necessary to achieve in-depth conformance control in the reservoir. Besides other parameters, the chemistry of injection water can significantly impact foam generation and stabilization. The tailored water chemistry was found to have good potential to improve foam stability. The objective of this study is to extensively evaluate the effect of different aqueous ions in the selected tailored water chemistry formulations on foam stabilization. Bulk and dynamic foam experiments were used to evaluate the impact of different tailored water chemistry aqueous ions on foam generation and stabilization. For bulk foam tests, the stability of foams generated using three surfactants and different aqueous ions was analyzed using bottle tests. For dynamic foam experiments, the tests were conducted using a microfluidic device. The results clearly demonstrated that the ionic content of aqueous solutions can significantly affect foam stabilization. The results revealed that the foam stabilization in bulk is different than that in porous media. Depending on the surfactant type, the divalent ions were found to have stronger influence on foam stabilization when compared to monovalent ions. The bulk foam results pointed out that the aqueous solutions containing calcium chloride salt (CaCl2) showed longer foam life with the anionic surfactant and very weak foam with the nonionic surfactant. The solutions with magnesium chloride (MgCl2) and CaCl2 salts displayed higher impact on foam stability in comparison with sodium chloride (NaCl) with the amphoteric alkyl amine surfactant. Less stable foams were generated with aqueous solutions comprising of both magnesium and calcium ions. In the microfluidic model, the solutions containing MgCl2 showed higher resistance to gas flow and subsequently higher mobility reduction factor for the injection gas when compared to those produced using NaCl and CaCl2 salts. This experimental study focusing about the role of different aqueous ions in the injection water on foam could help in better understanding the foam stabilization process. The new knowledge gained can also enable the selection and optimization of the right injection water chemistry and suitable chemicals for foam field applications.


Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 855
Author(s):  
Mikołaj Kokociński ◽  
Dariusz Dziga ◽  
Adam Antosiak ◽  
Janne Soininen

Bacterioplankton community composition has become the center of research attention in recent years. Bacteria associated with toxic cyanobacteria blooms have attracted considerable interest. However, little is known about the environmental factors driving the bacteria community, including the impact of invasive cyanobacteria. Therefore, our aim has been to determine the relationships between heterotrophic bacteria and phytoplankton community composition across 24 Polish lakes with different contributions of cyanobacteria including the invasive species Raphidiopsis raciborskii. This analysis revealed that cyanobacteria were present in 16 lakes, while R. raciborskii occurred in 14 lakes. Our results show that bacteria communities differed between lakes dominated by cyanobacteria and lakes with minor contributions of cyanobacteria but did not differ between lakes with R. raciborskii and other lakes. Physical factors, including water and Secchi depth, were the major drivers of bacteria and phytoplankton community composition. However, in lakes dominated by cyanobacteria, bacterial community composition was also influenced by biotic factors such as the amount of R. raciborskii, chlorophyll-a and total phytoplankton biomass. Thus, our study provides novel evidence on the influence of environmental factors and R. raciborskii on lake bacteria communities.


2021 ◽  
Vol 7 (7) ◽  
pp. 565
Author(s):  
Anindita Lahiri ◽  
Brian R. Murphy ◽  
Trevor R. Hodkinson

Fraxinus excelsior populations are in decline due to the ash dieback disease Hymenoscyphus fraxineus. It is important to understand genotypic and environmental effects on its fungal microbiome to develop disease management strategies. To do this, we used culture dependent and culture independent approaches to characterize endophyte material from contrasting ash provenances, environments, and tissues (leaves, roots, seeds). Endophytes were isolated and identified using nrITS, LSU, or tef DNA loci in the culture dependent assessments, which were mostly Ascomycota and assigned to 37 families. Few taxa were shared between roots and leaves. The culture independent approach used high throughput sequencing (HTS) of nrITS amplicons directly from plant DNA and detected 35 families. Large differences were found in OTU diversity and community composition estimated by the contrasting approaches and these data need to be combined for estimations of the core endophyte communities. Species richness and Shannon index values were highest for the leaf material and the French population. Few species were shared between seed and leaf tissue. PCoA and NMDS of the HTS data showed that seed and leaf microbiome communities were highly distinct and that there was a strong influence of Fraxinus species identity on their fungal community composition. The results will facilitate a better understanding of ash fungal ecology and are a step toward identifying microbial biocontrol systems to minimize the impact of the disease.


2015 ◽  
Vol 68 (2) ◽  
pp. 221-227 ◽  
Author(s):  
Cristina Paixão Araújo ◽  
João Felipe Coimbra Leite Costa

AbstractDecisions, from mineral exploration to mining operations, are based on grade block models obtained from samples. This study evaluates the impact of using imprecise data in short-term planning. The exhaustive Walker Lake dataset is used and is considered as the source for obtaining the true grades. Initially, samples are obtained from the exhaustive dataset at regularly spaced grids of 20 × 20 m and 5 × 5 m. A relative error (imprecision) of ±25% and a 10% bias are added to the data spaced at 5 × 5 m (short-term geological data) in different scenarios. To combine these different types of data, two methodologies are investigated: cokriging and ordinary kriging. Both types of data are used to estimate blocks with the two methodologies. The grade tonnage curves and swath plots are used to compare the results against the true block grade distribution. In addition, the block misclassification is evaluated. The results show that standardized ordinary cokriging is a better methodology for imprecise and biased data and produces estimates closer to the true grade block distribution, reducing block misclassification.


2017 ◽  
Vol 11 (1) ◽  
pp. 219-238 ◽  
Author(s):  
Laxmi Goparaju ◽  
P. Rama Chandra Prasad ◽  
Firoz Ahmad

Abstract Forests, the backbone of biogeochemical cycles and life supporting systems, are under severe pressure due to varied anthropogenic activities. Mining activities are one among the major reasons for forest destruction questioning the survivability and sustainability of flora and fauna existing in that area. Thus, monitoring and managing the impact of mining activities on natural resources at regular intervals is necessary to check the status of their depleted conditions, and to take up restoration and conservative measurements. Geospatial technology provides means to identify the impact of different mining operations on forest ecosystems and helps in proposing initiatives for safeguarding the forest environment. In this context, the present study highlights the problems related to mining in forest ecosystems and elucidates how geospatial technology can be employed at various stages of mining activities to achieve a sustainable forest ecosystem. The study collates information from various sources and highlights the role of geospatial technology in mining industries and reclamation process.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Rasmus H. Kirkegaard ◽  
Simon J. McIlroy ◽  
Jannie M. Kristensen ◽  
Marta Nierychlo ◽  
Søren M. Karst ◽  
...  

1983 ◽  
Vol 105 (4) ◽  
pp. 719-725 ◽  
Author(s):  
M. A. Hebbar ◽  
C. E. Sessions

The impact of Materials and Processes (M and P) development activities at the Nuclear Components Division - Breeder Reactor Components Project of Westinghouse are described. Nine specific M and P programs have been performed over the past five years and the conclusions drawn from each are summarized herein. These engineering activities could be classified as component design, fabrication, and testing results. However, the discussion presented is from a materials engineer’s viewpoint as to how the previously proposed development tasks have answered existing questions about either design, manufacturing, or plant operation. The nine areas which are discussed include (i) double-wall tubing, (ii) tube-to-tubesheet welding, (iii) few tube model fabrication and testing, (iv) tube support plates, (v) shell welding, (vi) convoluted shell expansion joint, (vii) water chemistry and corrosion behavior, (viii) chemical cleaning, and (ix) surface contamination protection.


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