Geochemical transformation of soil cover and vegetation in a drained floodplain lake affected by long-term discharge of effluents from rayon industry plants,lower Don River Basin,Southern Russia

Environmental Geochemistry and Health - Lake Atamanskoye is one of the most polluted aquatic environments in the South of Russia. This water body was affected by long-term pollution by effluent...     

Pollution status and human health risk assessment of potentially toxic elements and polycyclic aromatic hydrocarbons in urban street dust of Tyumen city,Russia

Environmental Geochemistry and Health - This study investigated levels and sources of pollution and potential health risks associated with potentially toxic elements (PTEs) and polycyclic aromatic...     

Morphological evidence for vertical transmission of symbiotic bacteria in the viviparous sponge<Emphasis Type="Italic"> Halisarca dujardini</Emphasis> Johnston (Porifera,Demospongiae, Halisarcida)

All stages of vertical transmission of symbiotic bacteria, from the penetration into oocytes to the formation of rhagon, were investigated in the White Sea (Arctic) representatives of Halisarca dujardini Johnston (Demospongiae). Small populations of free-living specific symbiotic bacteria inhabit the mesohyl of H. dujardini. They are represented by a single morphotype of small spiral gram-positive bacteria. Vertical transmission of symbiotic bacteria between generations in sponges may occur in different ways. In the case of H. dujardini the bacteria penetrate into growing oocytes by endocytosis. A part of the bacteria plays a trophic role for oocytes and the other part remains undigested in membrane-bound vacuoles within the cytoplasm. In cleaving embryos bacteria are situated between the blastomeres or in the vacuoles. In the blastula all bacteria are disposed in the blastocoel. The symbionts are situated in intercellular spaces in free-swimming larvae and during metamorphosis. Symbiotic bacteria do not play any trophic role in the period of embryonic and postembryonic development of H. dujardini. No signs of destruction and digestion of bacteria were revealed at any stage of development.Communicated by O. Kinne, Oldendorf/Luhe     

Comparison of concentrations of toxic elements in the hair of first-year students of RUDN University from different regions of the world: a cross-sectional study

Environmental Science and Pollution Research - Due to the development of the metallurgical and energy industries and the operation of incinerators, more and more environmental pollution is...