Trace element accumulation in Baikal seal (Phoca sibirica) from the Lake Baikal

Trace element concentrations (Fe, Mn, Zn, Cu, Pb, Ni, Cd, Co and Hg) were determined in 60 Baikal seals and in fishes collected from Lake Baikal in 1992. Low levels of Hg and Cd were found in Baikal seals in comparison with those of marine mammals and it was due to their low concentrations in dietary fish. These results suggest that pollution by Hg and Cd was low in Lake Baikal and these toxic elements were unlikely to be the causative factors for mass mortality of Baikal seal in 1987-1988. Significant correlation of Hg concentration between hair and internal tissues suggested the use of hair for Hg monitoring in pinnipeds. Among essential elements, higher Fe and lower Cu levels were specifically found in the liver of Baikal seal. The noticeable accumulation of essential elements might be related to the unique and specific environment of Lake Baikal.     

The "Linh Duong" Pseudonovibos spiralis (Mammalia, Artiodactyla) is a new buffalo

The controversial phylogenetic position of the recently described South-East Asian endemic bovid, Pseudonovibos spiralis, was evaluated on the basis of phylogenetic analyses of originally obtained nearly complete 12S mitochondrial rDNA sequences for this species and Bubalus bubalis and 26 sequences of Bovidae from the Genbank using Cervus elaphus (Cervidae) as outgroup. In most of the phylogenetic analyses performed using PAUP 4.0 (maximum parsimony, maximum likelihood and neighbour-joining), Bovidae consisted of two major clades: Bovinae including the tribes Bovini, Tragelaphini and Boselaphini, and Antilopinae + Caprinae, incorporating all other bovids. In most trees P. spiralis fell within the buffalos (subtribe Bovina) between Bubalus and Syncerus. Therefore, our phylogenetic analyses of bovid mitochondrial 12S rRNA gene sequences suggest the close relationship of this enigmatic species with the buffalos and its placement within the subtribe Bovina.     

Biochar reduces the toxicity of silver to barley (Hordeum vulgare) and springtails (Folsomia candida) in a natural soil

Environmental Science and Pollution Research - The use of biochar in soil remediation is a promising method to deal with metal contamination. In the present study, the influence of biochar...     

Small mammals in undisturbed and restored tundra biogeocenoses

Small mammal communities have been studied in undisturbed and restored zonal biogeocenoses in the southern subzone of eastern European tundras. The results show that the consequences of anthropogenic disturbances to the environment have an adverse effect on parameters of abundance, spatial distribution, and population dynamics of species comprising zonal communities. Soil and plant components of the disturbed biogeocenosis recover more rapidly than its small mammal community.     

Aliphatic–Aromatic Polyols by Thiol–Ene Reactions

Aliphatic–aromatic polyols were synthesized by thiol–ene reactions (photochemical or thermal) using mercaptanized starting materials from bio-based compounds: limonene dimercaptan, thioglycerol, mercaptanized castor oil and isosorbide (3-mercaptopropyl) ether. Aromatic starting materials were phenols containing double bonds; ortho-allyl phenol (OAP, petrochemical-based) and eugenol (EUG, bio-based). The phenolic hydroxyl groups were blocked by alkoxylation with propylene oxide (PO) or glycidol (GLY) prior to use in thiol–ene reaction. The aromatic rings were attached to the mercaptans by reacting thiol groups with the double bonds of alkoxylated OAP (OAP–PO and OAP–GLY) and alkoxylated EUG (EUG–PO and EUG–GLY). These synthesized aliphatic–aromatic polyols were utilized for preparation of rigid polyurethane foams whose physical–mechanical properties were superior to those made only from bio-based aliphatic polyols. These rigid PU foams can be used in a wide range of applications; such as thermal insulation of freezers, buildings, pipes and storage tanks for food and chemical industries, as wood substitute, packaging materials and flotation materials.     

Study of soil-plant transfer of 226Ra under greenhouse conditions

A soil-plant transfer study was performed using soil from a former uranium ore processing factory in South Bohemia. We present the results from greenhouse experiments which include estimates of the time required for phytoremediation. The accumulation of ²²⁶Ra by different plant species from a mixture of garden soil and contaminated substrate was extremely variable, ranging from 0.03 to 2.20 Bq ²²⁶Ra/g DW. We found differences in accumulation of ²²⁶Ra between plants from the same genus and between cultivars of the same plant species. The results of ²²⁶Ra accumulation showed a linear relation between concentration of ²²⁶Ra in plants and concentration of ²²⁶Ra in soil mixtures. On the basis of these results we estimated the time required for phytoremediation, but this appears to be too long for practical purposes.     

Polyacetal Polyols for Polyurethanes

The synthesis of telechelic polyacetals with terminal hydroxyl groups (polyacetal polyols), by the reaction of triethylene glycol divinyl ether with dipropylene glycol in the presence of trimethylolpropane or other triols or diols as starters, in acidic catalysis, has been studied. The synthesized liquid polyacetal triols and polyacetal diols were characterized by hydroxyl number, viscosity, acidity, number average molecular weight (M_n), weight average molecular weight (M_w), molecular weight distribution (M_w/M_n), FT-IR spectra. The obtained polyacetals were transformed in cast elastomers by the reaction with the isocyanate Mondur CD (modified diphenyl methane diisocyanate) with properties very close to the elastic polyurethanes obtained by using conventional polyether triols, copolymers propylene oxide–ethylene oxide. The polyacetal polyols are suitable for the synthesis of elastic polyurethanes (polyurethane elastomers, flexible polyurethane foams). Polyacetals are well known biodegradable polymers. Therefore, the polyurethanes based on polyacetal polyols are expected to be biodegradable.