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Tytuł:
Heavy Subgraph Conditions for Longest Cycles to Be Heavy in Graphs
Autorzy:
Lia, Binlong
Zhang, Shenggui
Powiązania:
https://bibliotekanauki.pl/articles/31340942.pdf
Data publikacji:
2016-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
heavy cycles
heavy subgraphs
Opis:
Let G be a graph on n vertices. A vertex of G with degree at least n/2 is called a heavy vertex, and a cycle of G which contains all the heavy vertices of G is called a heavy cycle. In this note, we characterize graphs which contain no heavy cycles. For a given graph H, we say that G is H-heavy if every induced subgraph of G isomorphic to H contains two nonadjacent vertices with degree sum at least n. We find all the connected graphs S such that a 2-connected graph G being S-heavy implies any longest cycle of G is a heavy cycle.
Źródło:
Discussiones Mathematicae Graph Theory; 2016, 36, 2; 383-392
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distribution of Heavy Metal Fractions in Sewage Sludge from a Selected Municipal Sewage Treatment Plant
Autorzy:
Wojciula, Ada
Boruszko, Dariusz
Kacprzak, Amadeusz
Powiązania:
https://bibliotekanauki.pl/articles/2069929.pdf
Data publikacji:
2021
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
sewage sludge
heavy metals
heavy metal fraction
Opis:
Sewage sludge used for reclamation of egraded areas or in agriculture must have a certain total heavy metal content, as required by law. In practice, however, it is important to carry out a fractional analysis of the elements contained in the sludge. This activity allows to determine the chemical form of a given metal, thanks to which it is possible to assess the assimilability of elements by plants. The study proved that the fraction of certain metals in sewage sludge can vary depending on the period studied. The combination of elements with other compounds in sludge from one treatment plant can vary from month to month. Once analysis has been carried out, it should not be the basis for assessing the bioavailability of metals if sludge from a given treatment plant were to be sampled several times a year.
Źródło:
Rocznik Ochrona Środowiska; 2021, 23; 369--383
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Heavy Metal Fraction Content in Sewage Sludge from Selected Wastewater Treatment Plants
Autorzy:
Wojciula, Ada
Boruszko, Dariusz
Pajewska, Gabriela
Powiązania:
https://bibliotekanauki.pl/articles/1839655.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
sewage sludge
heavy metals
heavy metal fraction
Opis:
Assessment of the assimilability of elements contained in sewage sludge can only be carried out if their fractions, by means of which the chemical form of the element can be identified, are determined. The total content of heavy metals only makes it possible to determine whether the sludge meets the legal requirements and can be used, inter alia, for reclamation, in agriculture or for the adaptation of land to specific needs that result from waste management plans. Therefore, when planning the agricultural use of sewage sludge, attention should be paid above all to the heavy metal fractions contained in it. This is due to the fact that plants do not assimilate every form of element to the same extent. The research and analysis carried out indicate that the metals were most closely related to fractions IV and III, for example they formed connections with silicates, as well as sulphides and organic matter. The metal forms available to plants occupied a small percentage of the total heavy metal content. It was noted that with the metastable fraction of lead increased along with population equivalent. Furthermore, the population equivalent value did not affect the distribution of individual heavy metal fractions in the sludge.
Źródło:
Journal of Ecological Engineering; 2021, 22, 4; 98-105
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Implicit Heavy Subgraphs and Hamiltonicity of 2-Connected Graphs
Autorzy:
Zheng, Wei
Wideł, Wojciech
Wang, Ligong
Powiązania:
https://bibliotekanauki.pl/articles/32083821.pdf
Data publikacji:
2021-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
implicit degree
implicit o-heavy
implicit f-heavy
implicit c-heavy
Hamilton cycle
Opis:
A graph G of order n is implicit claw-heavy if in every induced copy of K1,3 in G there are two non-adjacent vertices with sum of their implicit degrees at least n. We study various implicit degree conditions (including, but not limiting to, Ore- and Fan-type conditions) imposing of which on specific induced subgraphs of a 2-connected implicit claw-heavy graph ensures its Hamiltonicity. In particular, we improve a recent result of [X. Huang, Implicit degree condition for Hamiltonicity of 2-heavy graphs, Discrete Appl. Math. 219 (2017) 126–131] and complete the characterizations of pairs of o-heavy and f-heavy subgraphs for Hamiltonicity of 2-connected graphs.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 1; 167-181
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Content of Heavy Metals and Their Fractions in Organic Soils of Podlasie
Autorzy:
Wiater, Józefa
Powiązania:
https://bibliotekanauki.pl/articles/124491.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
heavy metal
organic soils
speciation of heavy metals
Opis:
The purpose of this study was to determine the total content of cadmium, lead, nickel, copper, zinc and their fractions in organic soils of Podlasie used as permanent grassland. The research material were samples taken from 30 soils of the Podlasie province in 2011-2013. The samples were taken from the determined layer to depth of 0-30 cm. Basic physicochemical properties were determined in the taken soil samples: organic carbon content, pH in 1 M KCl potentiometrically. The total content of metals after mineralization in aqua regia was determined, and cadmium fractions were determined with a modified BCR method. The measurements were conducted by means of atomic absorption spectroscopy with electrothermal atomization using Varian AA-100 spectrometer. It was found that only 2 soils can be included in the soils with first pollution degree due to the cadmium content. The content of other metals was at geochemical background level. The distribution of investigated metals in the fractions in studied organic soils was different comparing to mineral soils. Most of the analyzed elements were present in the fraction associated with organic substance, which limited their mobility, as evidenced by their low share in the available and potentially available fraction. The proportion of metals in the residual fraction was low, which is typical for organic soils. The share of studied metals in particular fractions varied depending on the sampling date, which may be related to the climatic conditions course in the study period and the treatments performed on these soils.
Źródło:
Journal of Ecological Engineering; 2019, 20, 3; 179-184
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heavy-mineral analysis in Polish investigations of Quaternary deposits: a review
Autorzy:
Marcinkowski, Bogusław
Mycielska-Dowgiałło, Elżbieta
Powiązania:
https://bibliotekanauki.pl/articles/94664.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
heavy mineral analysis
heavy mineral resistance
heavy mineral habit
heavy mineral density
Polska
analiza ciężkich minerałów
odporność ciężkich minerałów
gęstość mineralna
Polska
Opis:
The composition of heavy-mineral assemblages is one of the main textural features of sediments because they can have significant value for the interpretation of, among others, their depositional environment, their depositional processes, and their stratigraphic position. Distinctive features of heavy minerals include their resistance to chemical weathering and mechanical abrasion, their habit, and their density. These parameters are the most widely used in the heavy-mineral research of Quaternary deposits in Poland, as well as in such research in other countries conducted by Polish scientists. Several other heavy-mineral parameters can also be used in various types of interpretation. It is discussed whether heavy-mineral analysis is decisive in the evaluation of deposits or whether it plays mainly a role that may support evidence obtained by other types of analysis. The attention is mainly devoted to transparent heavy minerals; the significance of opaque heavy minerals for interpretational purposes is only mentioned.
Źródło:
Geologos; 2013, 19, No. 1-2; 5-23
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heavy Metals in Soils
Autorzy:
Draszawka-Bołzan, Beata
Powiązania:
https://bibliotekanauki.pl/articles/1153848.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
heavy metals
soils
Opis:
For the purposes of this Issue Paper, metals most commonly found at Superfund sites will be discussed in terms of the processes affecting their behavior in soils, as well as in those of the laboratory methods available to evaluate this behavior. The retention capacity of soil will also be discussed with regard to the movement of metals between the other environmental compartments: ground water, surface water, or the atmosphere. Long-term changes in soil environmental conditions, due to the effects of remediation systems or to natural weathering processes, are also explained with respect to the enhanced mobility of metals in soils.
Źródło:
World News of Natural Sciences; 2015, 2; 20-37
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Leaching of heavy metals from monolithic waste
Autorzy:
Mizerna, K.
Król, A.
Powiązania:
https://bibliotekanauki.pl/articles/208246.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
heavy metals
leaching heavy metals
metale ciężkie
wymywanie metali ciężkich
Opis:
Leaching of heavy metals (Zn, Pb, Cu, Ni and Cr) from hazardous waste originating from steel works (slag) has been investigated. Contaminant leaching behavior from monolithic waste materials in the function of time was examined. There was established the cumulative leaching of elements per surface area of waste material and the impact of the duration of the leachant contact with the waste on the leachability. The types of processes accompanying the release of heavy metals were determined as well. Surface wash-off and dissolution were dominant processes during the leaching of the analyzed elements. Chromium was the only element whose release from the sample was controlled by diffusion when subjected to leaching in a liquid of pH 7. Due to the low levels of heavy metal leaching in relation to their concentrations in the samples, it seems that longer duration of the tank test can contribute to the release of additional amounts of the heavy metals.
Źródło:
Environment Protection Engineering; 2018, 44, 4; 143-158
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Beneficiation of oxide ores using dense medium cyclones. A simulation study
Autorzy:
Aghlmandi Harzanagh, A.
Ergun, S. L.
Gulcan, E.
Powiązania:
https://bibliotekanauki.pl/articles/110337.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
heavy medium cyclone
heavy liquid
simulation
iron ores
manganese
chromite
Opis:
Recent investigations of particle behavior and segregation phenomena in a cyclone underline that little is known about particle distribution within a heavy medium separation. For this purpose, density profiles in a heavy medium cyclone (HMC) is measured with techniques such as computational fluid dynamics (CFD) in combination with discrete element modelling (DEM), electrical resistance tomography (ERT), X-ray tomography, particle dynamics analyzer (PDA) etc. Along with these modern efforts of determining the performance of HMC, traditional methods depending on empirical inferences based on experimental data are still important and in progress. The aim of this research was to investigate the possibility of using HMC for the concentration of problematic ores which are not coarsely aggregated. Towards this purpose, current empirical methods were applied to experimental data which were derived from float-sink tests of selected heavy minerals and Fe, Mn, and Cr ore samples. Low density difference between particles made the enrichment difficult using other gravity methods like jigs and shaking tables. After determining physical and mineralogical properties of the samples, appropriate size fractions were prepared for float-sink tests. Combination of sodium polytungstate and tungsten carbide powder were used to prepare non-toxic heavy liquids with density up to 3.5 g/cm3. Using the sink-float test results and existing empirical models for high-density DMC plants simulations were performed. The results of the simulations followed by experimental studies showed that HMCs are applicable to process Fe, Mn, and Cr ores with acceptable grade and recovery.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 1; 379-393
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sewage sludge as barrier material for heavy metals in waste landfill
Autorzy:
Zhang, H.
Yang, B.
Zhang, G.
Zhang, X.
Powiązania:
https://bibliotekanauki.pl/articles/204656.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sewage sludge
hydraulic conductivity
heavy metal pollution
heavy metal retardation
Opis:
Heavy metal pollutants in the leachate of waste landfill are a potential threat to the environment. In this study, the feasibility of using municipal sewage sludge as barrier material for the containment of heavy metal pollutants from solid waste landfills was evaluated by compaction test and hydraulic conductivity test concerning compaction property, impermeability and heavy metal retardation. Results of the compaction test showed that the maximum dry density of 0.79 g·cm−3 was achieved at the optimum water content of about 60%. The hydraulic conductivities of compacted sewage sludge permeated with synthetic heavy metal solutions were in the range of 1.3×10−8 – 6.2×10−9 cm·s−1, less than 1.0 ×10−−7cm·s−1 recommended by regulations for barrier materials. Chemical analyses on the effluent from the hydraulic conductivity tests indicated that the two target heavy metals, Zn and Cd in the permeants were all retarded by compacted sewage sludge, which might be attributed to the precipitation and adsorption of heavy metal ions. The results of this study suggest that specially prepared material from sewage sludge could be used as a barrier for waste landfills for its low permeability and strong retardation to heavy metal pollutants.
Źródło:
Archives of Environmental Protection; 2016, 42, 2; 52-58
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of bottom sediment on content, bioaccumulation and translocation on heavy metals in maize biomass
Wplyw osadu dennego na zawartosc, bioakumulacje i translokacje metali ciezkich w biomasie kukurydzy
Autorzy:
Jasiewicz, C
Baran, A.
Tarnawski, M.
Powiązania:
https://bibliotekanauki.pl/articles/16168.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie / Polskie Towarzystwo Magnezologiczne im. Prof. Juliana Aleksandrowicza
Tematy:
bottom sediment
heavy metal content
bioaccumulation
translocation
heavy metal
maize
biomass
Opis:
The research aimed to assess the effect of bottom sediment on the content, bioaccumulation and translocation of heavy metals in maize biomass. The investigations were conducted in 2006-2007 as a pot experiment on light soil of the granulometric composition of weakly-loamy sand. The experimental design comprised 3 treatments: without sediment (I), a 5% sediment admixture (II) and a 10% sediment admixture to the soil (III). Bottom sediment was added to the soil in the first year of the investigations. The content of Zn, Cu, Ni. Pb, Cd and Cr was determined using the ICP-EAS method in the plant material after its dry mineralization and ash solution in HNO3. The uptake of the above-mentioned metals by maize was computed alongside their bioaccumulation and translocation coefficients. The effect of bottom sediment admixture on heavy metal concentrations in maize was determined to be varied, e.g. a 5% dose of sediment added to soil decreased the content of all the analyzed heavy metals in the biomass of maize aerial parts, whereas a 10% admixture increased the content of Cu, Ni, Pb and Cr. The values of bioaccumulation coefficients revealed that an admixture of both doses of bottom sediment led to a decreased accumulation of Zn, Cu, Cd, Cr and Ni (5% dose) in maize aerial biomass. Moreover, the plant more easily accumulated Zn, Cd and Cu than Cr, Ni or Pb. Permissible amounts of heavy metals in plants to be used as animal fodder were not exceeded in the maize biomass.
Celem badań była ocena wpływu osadu dennego na zawartość, bioakumulację i translokację metali ciężkich w biomasie kukurydzy. Badania prowadzono w latach 2006-2007, w warunkach doświadczenia wazonowego, na glebie lekkiej o składzie granulometrycznym piasku słabogliniastego. Schemat doświadczenia obejmował 3 obiekty: bez osadu (I), z dodatkiem 5% osadu (II) i dodatkiem 10% osadu do gleby (III). Osad denny dodano do gleby w pierwszym roku badań. Zawartość Zn, Cu, Ni, Pb, Cd, Cr w materiale roślinnym oznaczono po suchej mineralizacji i roztworzeniu popiołu w HNO3. Obliczono wynos ww. metali przez kukurydzę oraz ich współczynniki bioakumulacji i translokacji. Stwierdzono niejednoznaczny wpływ dodatku osadu dennego na zawartość metali ciężkich w kukurydzy. Osad dodany w ilości 5% do gleby wpłynął na zmniejszenie zawartości wszystkich analizowanych metali w nadziemnej biomasie kukurydzy, natomiast 10% dodatek osadu na zwiększenie ich zawartości (Cu, Ni, Pb, Cr). Wartości współczynników bioakumulacji świadczą, że dodatek osadu dennego w obu dawkach spowodował zmniejszenie akumulacji Zn, Cu, Cd, Cr oraz Ni (dawka 5%) w biomasie nadziemnej kukurydzy, ponadto rośliny łatwiej akumulowały Zn, Cd i Cu niż Cr, Ni i Pb. W biomasie kukurydzy nie stwierdzono przekroczenia dopuszczalnych zawartości metali ciężkich przyjętych do oceny roślin pod względem ich przydatności paszowej.
Źródło:
Journal of Elementology; 2010, 15, 2; 281-290
1644-2296
Pojawia się w:
Journal of Elementology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metale ciężkie - korzyści i zagrożenie dla zdrowia i środowiska
Heavy metals – Benefits and hazards for the health and the environment
Autorzy:
Kondej, D.
Powiązania:
https://bibliotekanauki.pl/articles/180493.pdf
Data publikacji:
2007
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
metale ciężkie
zatrucie metalami ciężkimi
heavy metals
poisoning by heavy metals
Opis:
W artykule przedstawiono zagadnienia dotyczące występowania metali ciężkich w środowisku życia i pracy człowieka. Scharakteryzowano wybrane metale ciężkie niezbędne dla zdrowia człowieka oraz toksyczne metale ciężkie. Opisano objawy zatrucia wybranymi metalami ciężkimi oraz sposoby zapobiegania im.
This paper presents issues related to heavy metals in residential and occupational environments. It characterizes both heavy metals essential for good health and toxic heavy metals. Symptoms of toxicological effects are presented and prevention of heavy metal poisoning is discussed.
Źródło:
Bezpieczeństwo Pracy : nauka i praktyka; 2007, 2; 25-27
0137-7043
Pojawia się w:
Bezpieczeństwo Pracy : nauka i praktyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heavy metals distribution in different soil series of district Swabi, Khyber Pakhunkhawa, Pakistan
Autorzy:
Jamal, Aftab
Sarim, Muhammad
Powiązania:
https://bibliotekanauki.pl/articles/1166358.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Heavy metals
Swabi soils
Opis:
The present research was carried out with the main aim to evaluate the levels of heavy metals in some contaminated or expected to be contaminated by industrial effluents and some non contaminated soils of district Swabi. A total of 30 soil samples were collected from 15 different selected soil series of Swabi area at 0-15 cm and 15-30 cm depths and analyzed for various chemical properties using standard analytical techniques and for extractable heavy metals Zn, Cu, Fe, Cr, Co, Ni, Cd and Pb using Atomic Absorption Spectrophotometer. All soil samples were found non saline having EC values between 0.13-0.56 dsm-1. Soil reaction or pH value ranged from 7.21-8.60 except Mansabdar soil which had pH value of 9.21. It was found that swabi soil was moderately to strongly calcareous in nature, alkaline in reaction having deficient to marginal in organic matter content. Furthermore all soil samples were found almost adequate in Fe, Cu and Zn for most of agriculture crops. The higher concentrations of Ni (22.21 and 21.9 mg kg-1) and Cr (8.02 and 5.11 mg kg-1) at both surface and sub surface were recorded in Gadoom Amazai soils located near ghee mills and many other industries. Higher levels of heavy metals were observed in contaminated soils as compared with non contaminated soils. Decreased in concentration levels of metals were observed in majority of soils with increase in depth. No correlation was found between AB-DTPA extractable heavy metals and soil chemical properties and it might be due to samples collected from different locations with different thermodynamic characteristics.
Źródło:
World Scientific News; 2018, 105; 1-13
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heavy metals in circulation biogeochemical
Autorzy:
Cyraniak, Emil
Draszawka – Bołzan, Beata
Powiązania:
https://bibliotekanauki.pl/articles/1194079.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
biogeochemical
circulation
heavy metals
Opis:
Heavy metals can come from two types of sources: natural and anthropogenic. Natural origin of heavy metals associated with: volcanic eruptions, weathering of rocks, processes soil - creative, forest fires or evaporation of the oceans. Anthropogenic sources of pollution these elements is primarily the burning of fuels, both in power and heating plants and power plants as well as regional and local municipal boiler houses, as well as in the home. In addition to the natural environment gets heavy metals as a result of non-ferrous metals and iron, waste incineration and transport. The rapid development of technology and the changes that are occurring in the world today largely affect on the environment. One of the primary sources of pollution of the biosphere are industrial plants, which emit both gaseous substances (eg. Carbon monoxide, sulfur and nitrogen) and dust, containing all sorts of toxic substances. For the serious consequences of the development of civilization and industry should be spread include heavy metals [6]. Included in the atmosphere, dust and heavy metals fall to the ground parts of plants and enters the soil. Shall be collected by the roots of plants or animals grazing on the roads and thus incorporated into the food chain. These elements are not biodegradable.
Źródło:
World Scientific News; 2014, 6; 10-16
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The school performance of boys from rural schools in Lower Silesia in the light of lead concentration in blood
Osiągnięcia szkolne chłopców z Dolnego Śląska w świetle stężenia ołowiu we krwi
Autorzy:
Żurek, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/1178966.pdf
Data publikacji:
2012
Wydawca:
Instytut Medycyny Wsi
Tematy:
heavy metals
school performance
Opis:
Research conducted in many research centers all over the world indicate health threats resulting from the presence of lead in the blood gradually decreases to the permissible amount. Lead accumulation in a living organism results in adverse changes in different body systems, symptoms of which include various behavioral changes. They can be reflected in grades obtained by the child at school. The aim of this paper was to establish whether the blood lead level diversify the boys in the respect of their school performance during consecutive years of primary education. The amount of lead in blood of 94 boys at the age of 10 has been measured; subsequently, the group of subjects was divided into two subgroups; the first one (termed in this paper „L”) comprised students whose Pb-B level was lower than 6 μg/dl (4,846 μg/dl on average) and the second one (termed „H”) comprised boys whose blood level exceeded 6 μg/dl (9,256 μg/dl on average). Academic performance in the arts, scientific subjects, geography and natural science in respective groups was assessed. Said procedure was replicated in respective subgroups after a year when the subjects were 11 years old. It was ascertained that the academic performance of the boys with higher blood lead levels deteriorated in scientific subjects and tended to worsen also in other school subject groups. Performance of the students whose blood lead level was lower in the initial examination remained unchanged or improved.
Badania podejmowane w wielu ośrodkach naukowych na całym świecie, wskazujące na zagrożenia zdrowotne wynikające z obecności ołowiu we krwi, zaowocowały stopniowym obniżeniem dopuszczalnej zawartości tego metalu ciężkiego w organizmie. Konsekwencją jego kumulacji są bowiem niekorzystne zmiany obserwowane w układach wewnętrznych, których jednym z przejawów są m.in. różnego rodzaju zmiany behawioralne. Mogą one przekładać się na oceny uzyskiwane przez dziecko w szkole. Celem niniejszej pracy było określenie czy poziom ołowiu we krwi różnicuje chłopców pod kątem ich osiągnięć szkolnych w kolejnych latach kształcenia w szkole podstawowej. Wykonano pomiar zawartości ołowiu we krwi 94 chłopców 10-letnich, a następnie całą grupę badanych podzielono na dwie podgrupy; pierwszą (zwana umownie „N”), w której znaleźli się uczniowie, których poziom Pb-B był mniejszy niż 6 μg/dl (średnio 4,84 μg/dl) i drugą (W) o zawartości ołowiu we krwi przekraczającej ten poziom (średnio 9,25 g/dl). Wgrupach tych oceniono osiągnięcia w nauce z przedmiotów humanistycznych, ścisłych oraz geograficzno-przyrodniczych. Procedurę tę w wyodrębnionych podgrupach powtórzono w kolejnym roku, a więc wśród 11-latków, Wśród chłopców o wyższej zawartości ołowiu we krwi stwierdzono istotne obniżenie się wyników w nauce przedmiotów ścisłych oraz tendencję do obniżania się ocen z pozostałych grup przedmiotów. Uczniowie, których poziom ołowiu we krwi był niższy w badaniu wyjściowym utrzymali lub podnieśli poziom swoich osiągnięć szkolnych.
Źródło:
Medycyna Środowiskowa - Environmental Medicine; 2012, 15, 1; 27-31
1505-7054
2084-6312
Pojawia się w:
Medycyna Środowiskowa - Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 1650

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