ОСОБЕННОСТИ ФОТОМЕТРИЧЕСКОГО ОПРЕДЕЛЕНИЯ ОРГАНИЧЕСКОГО УГЛЕРОДА В ДОННЫХ ОТЛОЖЕНИЯХ

Abstract

Background. Organic matter in bottom sediments originates from plants and animals as a metabolic by-product; it determines biological productivity of a water body and physical and chemical properties of its bottom soils, enriches its aquatic environment with biogenic elements, and provides nutrients for its benthic communites, on which, in turn, feed benthophagous fish species. The most reprepresentative indicator of the organic matter in bottom sediments is organic carbon. Relevance. Currently, for determination of the organic carbon directly in bottom sediments, either expensive equipment or certified methods approved for soils are used. Aim. This work presents the results of development and validation of the method for quantitative determination of organic carbon in bottom sediments. Methods. The developed modification of I.V. Tyurin’s method is based on photometric detection of trivalent chrome that is equivalent to the content of oranic carbon after oxidation of the organic matter in bottom sediments in chromosulfuric acid. Chloride interference was precluded with silver sulphate; as a reference standard, the State Standard Sample of glucose was used for the first time. Results. This method has been tested on the bottom sediments of the Azov Sea, and the results are found to be in compliance with those obtained from the investigations conducted by the traditional Tyurin’s method with silver sulphate. This method does not require expensive equipment and is applicable for mass determination. Conclusion. Based on the results of this investigation, a metrological certification of the developed method has been conducted; it regulates the procedure for determination of carbon mass fractions in the bottom sediments of water bodies in the range from 0.3 to 16.0 %.