Microelements in anthropogenically contaminated soils in the central part of Petrozavodsk

Urban soils (Urbic Technosols) formed within or near the industrial sites removed of service show a considerable excess over the regional background in the content of Pb, Zn, Cu, Mn, Cr, Ni, as well as over the average content of W, Mo, Pb, Sb, Cr, Cu, Sn, Ni, Zn, and Mn in urban soils. Microelements are concentrated for the most part in the soil fine earth, and above all, in the fraction with particle size <0.1 mm. Surface films (on quartz and feldspar grains) of quartz–feldspar–muscovite (partially with tremolite and chlorite) composition and undifferentiated dispersed mixture of quartz, albite, microcline, muscovite and organomineral soil substance are the strongest concentrators of heavy metals and metalloids. Pb and Sn are partially present in soils as oxides, and a part of Zn and Pb, in the form of substantial admixtures to technogenic chemical compounds. As a whole, distribution of elements in the studied soils is controlled by the specifics and type of contamination, resistance of coarser grains to weathering under the given physicochemical conditions, and by predominantly mineral (quartz–feldspar) composition of the solids in soil layers and the features of elements proper.     

Fast HPLC for the analysis of oxygen heterocyclic compounds of citrus essential oils.

A fast HPLC method for the determination of the oxygen heterocyclic compounds of citrus essential oils was developed. Five different oils were analyzed under identical conditions, by reversed-phase HPLC with photodiode array detector, for a direct comparison of the composition of their oxygen heterocyclic fraction. Analysis time was 7 min. The oils analyzed were lemon, bergamot, mandarin, sweet orange, and bitter orange. The method developed is good for rapid screening or fingerprinting of these essential oils; a slightly slower method is recommended for higher resolution and better quantitative results.     

Extended-spectrum β-lactamase production in E. coli strains isolated from clinical bovine mastitis

Veterinary Research Communications -