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Accumulation of polonium by Mytilus trossulus under experimental conditions

100%

Stepnowski P. , Kożuch J.

tom Vol. 28, No. 1-2

73-82

The bioaccumulation of polonium in the Baltic mussel Mytilus trossulus was studied experi-mentally in an attempt to discover the differences between food and water as sources of polonium. The 209Po isotope was used as tracer for accumulation and excretion. The highest 209Po con-centration was found in the hepatopancreas of mussels exposed to spiked water for 24 days. Both parts of the experiment (exposure to food and water) showed that while the rate of bioaccumula-tion of polonium by Mytilus trossulus was very high, the excretion rate was also relatively high. Furthermore, in both cases the duration of the accumulation-excretion (a-e) cycle of polonium in Mytilus trossulus was 10 days. Finally, a simple mathematical model approximating the experimental data was developed.

Synteza oligoestrów tereftalowych z odpadowego poli(tereftalanu etylenu)

80%

Langer E. , Lenartowicz M. , Kożuch J. , Waśkiewicz S.

Przemysł Chemiczny

2012

tom T. 91, nr 8

1587-1590

Oracowano nową metodę otrzymywania oligoestrów tereftalowych w reakcji chemicznej degradacji poli(tereftalanu etylenu) PET. Jako surowce zastosowano odpadowy PET, 2-etyloheksanol, kwasy dikarboksylowe o zróżnicowanej długości łańcucha oraz poliole. Otrzymane oligoestry analizowano w celu określenia ich struktury, stosując spektroskopię NMR, spektrometrię ESI-MS oraz chromatografię żelową GPC. Pozwoliło to na dokładne poznanie struktury powstających produktów. W celu pełniejszego scharakteryzowania produktów syntezy wykonano również ich analizę termiczną (DSC, TGA). Dodatkowo przedstawiono wyniki badań, jakie uzyskano, stosując otrzymane oligoestry tereftalowe jako plastyfikatory PVC.

Poly(ethylene terephthalate) was degraded by transestrification with oligoesters made by conversion of azelaic or adipic acid, glycerol, diethylene or dipropylene glycol and 2-ethylhexanol at 190–210°C to resp. oligoterephthalates used then as plasticizers of poly(vinyl chloride) (PVC). Use of the plasticizers resulted in an improvement of mech. properties of PVC.

The influence of marine and lacustrine humic substances on the accumulation of cadmium by the Baltic mussel Mytilus trossulus

80%

Kożuch J. , Pempkowiak J. , Gjessing E.

tom No. 40 (1)

39-49

The accumulation of cadmium by the Baltic mussel Mytilus trossulus in the presence of marine and lacustrine humic substances (HS) was investigated under laboratory conditions. The tested organisms were exposed to Baltic Sea water (salinity 7.0 PSU, pH 7.85) spiked with cadmium (50 μg Cd l -1) and humic substances (6.0 mgHS l -1), isolated from either marine (6 sampling sites) or lacustrine (8 sampling sites) environments. Experiments were carried out at a constant seawater temperature of (10±C1oC). The exposure time was 21 days. On average, the humic substances, a fraction of naturally occurring organic matter, were found to stimulate cadmium accumulation in the mussels. Lacustrine humic substances stimulated cadmium uptake to a lesser extent than the marine ones. Cadmium was accumulated preferentially in the hepatopancreas, and to a smaller extent in the gills and muscles, regardless of the presence, properties and origin of the humic substances. However, the effect was modified by the dissimilar physical and chemical properties of the substances, which were related to their place of origin.