Wyniki wyszukiwania - Biblioteka Nauki

1

Influence of pH on concentration of Pb2+ ions in bulk precipitation and throughfall

100%

Kram K. J.

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tom Vol. 12, nr 12

1375-1380

EN

Studies were performed on H+ and Pb2+ input in hulk precipitation and throughfall of 5 forest ecosystems of Kampinoski National Park. There were stands with following dominant trees: pine, birch, false acacia, alder, and oak. The studies were carried out during the growing seasons (April-October) 1998-2000. Results of that studies showed strict correlation between acidity of rainfalls (bulk precipitation and throughfali) and concentration of lead ions - the higher concentration of H+ (lower pH) the higher concentration of Pb2+. Besides concentrations of lead in throughfall were higher then in hulk precipitation with similar acidity.

PL

W trakcie sezonu wegetacyjnego (kwiecień-październik) w latach 1998-2000 na terenie Kampinoskiego Parku Narodowego przeprowadzono badania składu chemicznego opadów atmosferycznych. Badania te były prowadzone zarówno na terenie otwartym, jak i pod koronami drzew 5 różnych drzewostanów. Były to drzewostany, w których dominującym gatunkiem drzew były: sosna, brzoza, robinia, olsza i dąb. Wyniki tych badań wykazały, że stężenie jonów ołowiu (Pb2+) zarówno w wodach deszczowych, jak i podkoronowych było ściśle związane z kwasowością tych wód - przy wyższym stężeniu H+ (mniejsze pH) wyższe było stężenie jonów ołowiu. Przy czym przy podobnej kwasowości zaobserwowano większe stężenia jonów ołowiu w wodach podkoronowych niż w wodach deszczowych.

2

Efficient solidification of Pb2+ by activated tungsten tailings and cement

99%

Cheng H. , Kuang J. , Zhu L. , Yuan W. , Huang Z. , Yang Y.

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tom Vol. 59, iss. 2

art. no. 162618

EN

The preparation of cementing admixture from tailings and co-solidification of Pb2+ with cement is a green way to realize the resource utilization of tailings and treatment of the lead-containing wastewater. In this paper, the tungsten tailings were activated in different ways, and the mechanical properties of the tungsten tailings-cement solidified body with different activation systems and the solidification behavior of Pb2+ were studied. The phase and microstructure of the hydrated product were characterized by XRD, FT-IR, SEM and EDS. The results showed that the curing effect of Pb2+ was obviously different of different activation systems, and the curing effect of the solidified body of the ternary composite activation system (TCAS) was the best, second only to the pure cement system (PCS). Different activation methods have a significant impact on the mechanical properties of the solidified body. With the increase of the Pb2+ content, the compressive strength of the solidified body gradually decreased, the Pb2+ leaching concentration gradually increased; with the extension of the curing age, the compressive strength gradually increased, and the Pb2+ leaching concentration gradually decreased. In particular, the compressive strength of the 28d solidified body was 31.43 MPa and the leaching concentration of Pb2+ was only 0.38 mg/L when the Pb2+ content was 5%. The phase, microstructure and EDS results of the hydration products showed that Pb2+ was mainly solidified in the C-S-H gel.

3

Response of vitamins A, E, hematological and serum biochemical markers in Crucian carp (Carassius auratus gibelio) exposed to environmental Pb2+ and Cd2+

85%

Khan S. , Zhou P. , Liu X. , Li H. , Li J. , Rehman Z. u. , Ahmad I.

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nr 3

581-587

EN

Toxicity of Pb2+ and Cd2+ is a widespread issue in the world; however, few studies have been conducted to understand their effect at environmentally realistic concentration in a mixture. In the present study, Crucian carp was exposed to Pb2+ (30 µg·l-1), Cd2+ (100 µg·l-1) and their mixture (30+100 µg·l-1) for 96 h and 21 d period to assess changes in the liver and muscle vitamin A and E content, and hematological and serum biochemical parameters. The results indicated significant decline in the level of antioxidant vitamins A, E and alterations in the hematological and serum biochemical indices. The toxicity revealed anemia, impairment of the liver and kidney with evident responses after 21 d exposure due to additive effect of Pb2+ and Cd2+ in mixture. Moreover, the differential response of vitamins A, E and blood parameters to low levels of waterborne Pb2+ and Cd2+ in freshwater fish can be used as biomarkers for monitoring contamination of aquatic environment.

4

Effect of Pb(II) Ions on Mortality of the IJs of Steinernema Feltiae Filipjev and Heterorhabditis Megidis Poinar

57%

Jarmuł J. , Kamionek M.

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tom Vol. 7, nr 10

1023-1029

EN

An effect of lead nitrate on H. megidis and S. feltiae was studied. Changes: in the invasive properties of IJs exposed to Pb (II) ions; in the sexual structure of a nematode population developing in the host insect, and in viability of larvae migrating from the dead insect to the external environment were adopted as criteria of this effect. We used lead concentrations of 40, 100, 500 1000. and 5000 ppm Pb and an initial dose of 50 IJs per 1 G. melonella larvae. Preliminary results demonstrated that the presence of heavy metal ions affects the reproductive abilities of nematodes. S.feltiae totally loses its reproductive abilities with the increasing concentration of Pb+2 ions since almost all giant males die. H. megidis preserves its growth capabilities but the second generation is decimated before it attains the invasive stage.

PL

Badano wpływ azotanu ołowiu Pb(NO3)2 na H. megidis i S. feltiae. Jako kryteria oceny tego wpływu przyjęto zmiany: w inwazyjności IJs poddanych działaniu jonów Pb (II); w strukturze płciowej populacji nicieni rozwijającej się wewnątrz owada żywicielskiego oraz w żywotności larw migrujących z martwego owada do środowiska zewnętrznego. Zastosowano stężenia:40, 100, 500, 1000, 5000 ppm ołowiu oraz dawkę inicjalną 50 IJs na 1 larwę G. melonella. Na podstawie wstępnych wyników stwierdzono, że obecność jonów metali ciężkich w środowisku powoduje spadek inwazyjności larw inwazyjnych S. feltiae. Zależy on od stężenia jonów Pb2+.