secondary enrichment
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2021 ◽  
Vol 567 ◽  
pp. 120081
Author(s):  
Qiong Yang ◽  
Zhongfang Yang ◽  
Gabriel M. Filippelli ◽  
Junfeng Ji ◽  
Wenbing Ji ◽  
...  

2021 ◽  
Author(s):  
Anna Karczewska ◽  
Katarzyna Szopka ◽  
Agnieszka Dradrach ◽  
Bernard Gałka

<p>Spatial distribution of As in a surface soil layer was determined in three historical mining sites in the Sudetes where As ores were exploited and processed over the centuries: in Złoty Stok (formerly: Reichenstein), Radzimowice (Altes Berg) and Czarnów (Evelinensgluck). Of those sites, Złoty Stok that operated until 1962, is the largest one. Thirteen patches of land situated in all those sites (6, 4, and 3, respectively) were chosen for analysis, each with an area of 2-5 hectares. They differed in terms of sources of soil enrichment in As, land topography and various types of land use or habitats. Both soils that developed on waste rock dumps and tailings, as well as those in their surroundings were examined. Simplified maps of As concentrations in soils were drawn based on 15-20 screening points located in each area. Arsenic distribution in soils in a mini-scale was examined by collecting multiple samples from several spots (each with an area of 1-10 m<sup>2</sup>). Gangue rock material disposed on the dumps was highly heterogeneous and locally contained over 1% of As. Total As concentrations in soil samples varied in a broad range: 72–193000 mg/kg, and the highest local enrichment in As was identified in alluvial soils along a stream affected by acid mine drainage. Various factors responsible for As concentrations in soils, including the amounts inherited from the parent rocks as well as various processes of redistribution, transport and secondary enrichment were discusses. Related environmental risk associated with a likely processes of further As mobilization and transport has been assessed with considering various scenarios. Additionally, soil enrichment and contamination indices, commonly used in the literature, such as geoaccumulation index Igeo, enrichment factor EF according to Sutherland and Nemerow pollution index PI, were calculated for each of the areas under study. Their ambiguity and limited suitability for the assessment of soil contamination with As were critically discussed.   </p><p>This research was funded by the National Science Centre of Poland; Project No. 2016/21/B/ST10/02221</p>


2020 ◽  
Vol 10 (17) ◽  
pp. 6041
Author(s):  
Urszula Aleksander-Kwaterczak ◽  
Dariusz Ciszewski

Heaps of waste material constitute a serious environmental problem in regions where the historical exploitation and processing of metal ores has taken place. The presented paper describes the trace metal distribution in selected heaps in the lead-zinc mining area of an abandoned mine in Poland, as well as the soil horizons beneath. The study aims at the estimation of the metal remobilization rate in vertical profiles in the spontaneously afforested area in the context of the potential danger it poses to the local groundwater. Individual samples were taken from profiles dug in heaps found in deciduous and coniferous forests. The bulk density, pH, organic matter and carbonate content, as well as the concentration and chemical forms of metals were analysed. Buffer properties and the mineralogical composition were also determined for the selected samples. The investigation indicates excessive cadmium, zinc and lead concentrations in the analysed heap material and the significant secondary enrichment of former soil horizons. A large percentage of these metals occur in potentially mobile forms. It suggests that, despite the high pH of the heap material and the good buffer properties of soil, cadmium and to a lesser extent, zinc, has migrated downwards to depths of at least several dozen centimetres over a period of about 200 years. This is related to soil acidity, particularly in profiles abundant in organic matter resulting from the encroachment of forest communities, particularly of coniferous forest. Spontaneous afforestation forming the litter cover contribute to the stabilization of the heap material and limiting groundwater pollution. Even though specific remediation measures are not needed in this area, it requires long-term monitoring.


2020 ◽  
Vol 22 (1) ◽  
pp. 114-140
Author(s):  
Malcolm Thomas ◽  
Barry Rees ◽  
Gareth Emyr Evans ◽  
Nicola Thomas ◽  
Clive Williams ◽  
...  

This paper outlines the development of one integrated ITE programme that leads to two QTS pathways: Primary Post-Graduate Certificate in Education with Secondary Enrichment; and Secondary Post-Graduate Certificate in Education with Primary Enrichment. The integrated ITE programme AberTeach + enables student teachers to 'Teach beyond boundaries for an all-through experience'. This paper reviews the programme's conceptual framework and learning philosophy and in so doing, considers the core principles that influenced the design of the programme, as follows: Inclusive Partnership; Effective Pedagogy; Integrated Pedagogy; Specialised and Enriched Pedagogy; Shared and Reflective Pedagogy; Truly Collaborative Research Culture, Democratic Accountability and the eight principles of the Learning Philosophy. The paper proceeds to explain how the integrated programme is delivered via a cluster hub approach across 5 hub regions in Mid-Wales. In doing so, it outlines the role of the University staff and Lead and Partner school mentors as well as the minimum expectations for student teachers whilst on school experience. Consideration is also given to Welsh-medium provision and support as well as the centrality of research within the ITE Partnership as a whole. The paper closes by considering what is innovative about the programme and the benefits that student teachers gain from undertaking the programme.


2019 ◽  
Vol 20 (3) ◽  
pp. 323-336
Author(s):  
Bagai-ool Yu Saryg-ool ◽  
I. N. Myagkaya ◽  
I. S. Kirichenko ◽  
M. A. Gustaytis ◽  
O. V. Shuvaeva ◽  
...  

The paper presents data on two cores from the dispersion train of gold-bearing sulfide tailings in the Novo-Ursk deposit (Kemerovo region, Russia), where organic-bearing mud and natural organic matter are interbedded with cyanide tailings and acid mine drainage (AMD). The study focuses on speciation of Au, Ag and potentially toxic elements (PTE), including Fe, Cu, Zn, As, Se and Pb according to selective sequential extractions. Since large contents of elements are found in water solution and bound to Fe(III) compounds, sulfides and/or organic matter in both cores, the organic material behaves as a natural biogeochemical barrier for potentially toxic elements and precious metals released from AMD. The interaction with organic matter results in biogeochemical sorption and immobilization of elements and is favourable for secondary enrichment in gold and silver. It leads to immobilization of elements that further form new mineral phases or become partitioned between existing phases. On the other hand, very high concentrations of water-soluble and oxidizable species of PTE and Au, which are unstable in surface conditions and may become remobilized when the environment changes, make the organic material less workable and even potentially hazardous. Thus, both positive (secondary enrichment) and negative (pollution) effects should be taken into account in the planning and design of systems for purification, disposal of cyanide tailings and recovery of useful components from tailings using natural organic matter as a geochemical barrier.


2018 ◽  
Vol 81 (9) ◽  
pp. 1425-1431 ◽  
Author(s):  
TY SEXTON ◽  
IFIGENIA GEORNARAS ◽  
KEITH E. BELK ◽  
MARISA BUNNING ◽  
JENNIFER N. MARTIN

ABSTRACT The objective of this study was to assess the presence and characteristics of Salmonella enterica found in the synovial fluid of broiler carcasses. The synovial fluid of three individual joints from 500 broiler carcasses was individually sampled from five broiler processing facilities located in the Southeast and West regions of the United States (1,500 total samples). The external surface of broiler carcass was decontaminated before sampling of the shoulder, coxofemoral, and tibiofemoral joints. Individual samples were enriched, composited, and subjected to rapid PCR-based detection of Salmonella. Individual samples from any positive composites were also enriched before determination of Salmonella presence in the same manner. Positive individual samples were subjected to secondary enrichment before plating onto selective agar for isolation of Salmonella. Salmonella isolates were serotyped before determination of antimicrobial susceptibility. Overall, 1.00% (5 of 500 broiler carcasses) of composite samples and 0.47% (7 of 1,500 samples) of individual samples were positive for Salmonella. Five of the seven isolates were susceptible to all drugs tested and determined to be Salmonella Enteritidis. The remaining two isolates, identified as Salmonella Typhimurium, were resistant to streptomycin. To our knowledge, no previous assessments of Salmonella in the synovial fluid of broilers has been reported; however, results of the present study suggested that the synovial fluid may be a reservoir for Salmonella in broilers. Although the prevalence of Salmonella is low, this information provides valuable insight into potential poultry contamination pathways and warrants further exploration.


2017 ◽  
Vol 80 (10) ◽  
pp. 1768-1776 ◽  
Author(s):  
Dongxin Liu ◽  
Yan Wang ◽  
Yi Wang ◽  
Lu Zhang ◽  
Lijuan Luo ◽  
...  

ABSTRACT Listeriosis, the disease caused by pathogenic Listeria species, can present severe symptoms in susceptible people. The goal of this study was to develop a novel enrichment broth, Listeria allose enrichment broth (LAEB), to improve isolation of Listeria monocytogenes and Listeria ivanovii from samples through incorporating a specific carbohydrate and reducing inhibitor concentrations. Other coexisting bacteria, particularly Listeria innocua, can interfere with the isolation of pathogenic Listeria in such ways as overgrowth of L. innocua and the generation of inhibitory metabolites. The incorporation of allose into the novel LAEB was effective for slowing the growth of L. innocua and other nontarget microorganisms. We determined that 35°C and pH 7.0 under aerobic conditions are optimal for Listeria growth in this medium. The novelty of the use of LAEB is the single enrichment procedure at 35°C for 24 h, obviating the need for a secondary enrichment medium. In 50 simulated samples, the sensitivity of the LAEB method (86%) was higher than that of the International Organization for Standardization (EN ISO) method (70%). In 142 naturally contaminated samples tested, the isolation rate for pathogenic Listeria with the LAEB method was 26.0% (37 of 142 samples), which was significantly higher than the 17.6% (25 of 142 samples) for the EN ISO method. Higher isolation rates and a quicker and easier protocol make the novel LAEB method an appropriate alternative for the isolation of pathogenic Listeria.


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