Biomedical subjects

Eiliv Steinnes

Publications and source records attributed to Eiliv Steinnes.

22 records · Page 2Linked to original sources

PubMed2003

Influence of pH and TOC concentration on Cu, Zn, Cd, and Al speciation in rivers.

Dissolved ( < approximately 4 nm, dialysis in situ), colloidal ( < 0.45 microm filtered, minus dissolved) and particulate (total, minus < 0.45 microm filtered) concentrations of Cu, Zn, Cd, (Al) in eight (three) mining polluted rivers were determined by atomic absorption spectrometry (flame and graphite furnace). The metal size distribution in the rivers was compared to pH, Ca concentration, alkalinity, conductivity, and total organic carbon (TOC). Data plots based on the present and other studies also yielded information about the interrelations between TOC, pH and metal adsorption in rivers and lakes. Less than 10% of Cu, Zn, and Cd were sorbed on particles or colloids in two rivers with average pH at 3.1 and 5.1, whereas 46%, 21%, and 21% of Cu, Zn, and Cd, respectively, occurred in sorbed form in six pH neutral rivers. In three pH neutral rivers, on average 55% of Al was in colloidal form, whereas the dissolved and particulate fractions were 21% and 23%, respectively. Our data combined with data from similar studies support conclusions from other research suggesting that the percent fraction of metals adsorbed on particles rises steeply from almost zero to nearly 100% within a narrow and element specific pH range. Changes in TOC concentration seem capable of shifting the pH to % metal absorption curves in the order of one pH unit.

Adsorption↗

PubMed2003

The global re-cycling of persistent organic pollutants is strongly retarded by soils.

'Persistent organic pollutants' (POPs) are semi-volatile, mobile in the environment and bioaccumulate. Their toxicity and propensity for long-range atmospheric transport (LRAT) has led to international bans/restrictions on their use/release. LRAT of POPs may occur by a 'single hop' or repeated temperature-driven air-surface exchange. It has been hypothesised that this will result in global fractionation and distillation-with condensation and accumulation in polar regions. Polychlorinated biphenyls (PCBs)--industrial chemicals banned/restricted in the 1970s--provide a classic illustration of POP behaviour. A latitudinally-segmented global PCB inventory has been produced, which shows that approximately 86% of the 1.3 x 10(6) tonnes produced was used in the temperate industrial zone of the northern hemisphere. A global survey of background surface soils gives evidence for 'fractionation' of PCBs. More significantly, however, very little of the total inventory has 'made the journey' via primary emission and/or air-surface exchange and LRAT out of the heavily populated source regions, in the 70 years since PCBs were first produced. Soils generally occlude PCBs, especially soils with dynamic turnover of C/bioturbation/burial mechanisms. This limits the fraction of PCBs available for repeated air-soil exchange. The forested soils of the northern hemisphere, and other C-rich soils, appear to be playing an important role in 'protecting' the Arctic from the advective supply of POPs. Whilst investigations on POPs in remote environments are important, it is imperative that researchers also seek to better understand their release from sources, persistence in source regions, and the significant loss mechanisms/global sinks of these compounds, if they wish to predict future trends.

Arctic Regions↗

PubMed2002

Sorption of toxic heavy metals to soil.

The surface soil is a major recipient of pollutants, including heavy metals, through atmospheric deposition, agricultural practices, and waste disposal. In the present work the sorption capacity of different types of soils to toxic heavy metals, i.e. chromium, copper, cadmium and lead has been studied. Experimental adsorption data for metals to the soil obtained by the batch method were fitted by linear isotherm. The various soils showed a very different behaviour in sorption of heavy metals. The distribution coefficient Kd, which is an indication of the adsorbing capacity of the substrate, varies within a wide range, from 57 to 53,000 l kg-1. Desorption of metals from the solid phase was found to be small, indicating that the soil matrix is affecting the metal mobility by modifying the bonding of pollutants to the soil system consequently affecting the potential for soil remediation processes.

Adsorption↗

PubMedDate not supplied

Molecular defense systems are expressed in the king bolete (Boletus edulis) growing near metal smelters.

The induction of defense systems against metal exposure was investigated in 48 wild-growing fruiting bodies of the king bolete (Boletus edulis) from two areas polluted with several transition metals from smelters, as well as five reference areas. To determine the degree of metal exposure, cadmium (Cd), zinc (Zn), and copper (Cu) were determined in caps of fruiting bodies by atomic absorption spectrophotometry (AAS), whereas mercury (Hg) was determined by cold vapor atomic fluorescence spectrometry (CVAFS). Caps were analyzed further with respect to relative activities of the antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), as well as concentrations of total glutathione (GSHTOT = GSH + GSSG) and relative concentrations of heat shock protein 70 kDa (HSP70). The results showed that concentrations of the four metals, as well as SOD, CAT and HSP70, were significantly elevated in the exposed group (Mann-Whitney, P < or = 0.001). In contrast, GSHTOT was significantly lowered in the exposed group (P < or = 0.05). Significant positive correlations were established between concentrations of Cd, Zn, Hg, or Cu and activities of SOD (Spearman's P < or = 0.01 for the association between SOD and Cd, P < or = 0.001 for all other metal exposure parameters), CAT (P < or = 0.001 for all exposure parameters), or expression of HSP70 (P < or = 0.001 for all exposure parameters). Significant negative correlations were found between total GSH and Cd (P < or = 0.001), Zn (P < or = 0.001), or Hg (P < or = 0.05). We conclude that antioxidant enzymes are induced in wild-growing B. edulis exposed to environmentally relevant concentrations of potentially toxic transition metals; whereas the net consumption of GSH that occurs with increasing metal exposure may reflect GSH consumption by mechanisms of metal detoxification. Finally, the induction of HSP70 suggests that the antioxidant response and the mechanisms in which GSH is consumed are insufficient for protection against the harmful effects of severe metal stress.

Basidiomycota↗