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A study of the competitive sorption of heavy metals onto sediments by means of a planned multifactorial experiment yielded equations describing the mutual influence of the zinc(II), cadmium(II), lead(II), and copper(II) cations in the sorption process, with the coefficients in the equations indicating the degrees of this influence. The competition between the metal ions significantly increases their mobility. Lead(II) and copper(II) cations prevent the binding of cadmium(II) and zinc(II) cations to sediments and promote their mobilization. Cadmium is a serious threat to aquatic ecosystems because of its mobility and high toxicity. After refinement under natural conditions the resulting mathematical models can be used for assessing and predicting the environmental risks of water pollution. [ABSTRACT FROM AUTHOR]

The Zn, Cd, Pb, Cu, Mn, and Fe concentrations in sediments, bottom waters, and benthic macroinvertebrates (Amphipoda, Bivalvia, Gastropoda, Hirudinea, and Oligochaeta) collected at six coastal stations in the Eastern Gulf of Finland were determined with the aim to reveal the features of heavy metals bioaccumulation in the macrozoobenthos. It was shown that benthic macroinvertebrates accumulate Mn, Fe, and Zn more actively than Pb, Cu, and Cd, while Hirudinea and Oligochaeta worms have enhanced accumulative capacities as compared to amphipods and mollusks. A close relationship was found between the Zn and Pb concentrations in the sediments and amphipods, but for the other elements no reliable relationship was observed. It was recommended to use organisms of other trophic levels along with zoobenthos and data on heavy metal concentrations in sediments for chemical monitoring of coastal waters. [ABSTRACT FROM AUTHOR]

A simple method is proposed for the rapid determination of the brittleness of fibers. Measurement data are given for glass and carbon fibers. It is shown that the conditions of heat processing for carbon fibers may fundamentally alter their brittleness. [ABSTRACT FROM AUTHOR]