Metamorphization of Bottom Sediments under Uncontrolled Discharge of Waste Waters into the Litoral Zone of the Herakleisky Peninsula (Crimea)

Based on the data of field research performed in 2015, the authors studied characteristics of bottom sediments in the area of a deepwater sewage collector of “Yuzhnye” Integrated Sewage Treatment Plant and transformation of bottom sediments resulted from a longterm anthropogenic impact. The data were obtained by standard methods of geochemical analysis. It is established that the bottom sediments in the wastewater discharge area of “Yuzhnye” Integrated Sewage Treatment Plant are represented by rudaceous and coarsegrained fractions. These are mineral particles formed both as a result of coastal abrasion and in the process of accumulation and diagenesis (shell rock, detrital sand) of bottom sediments. In terms of their size distribution and chemical composition they differed significantly from the sediments formed under natural conditions. These were mostly unconsolidated water-saturated sediments with low carbonate content, high organic carbon and moisture content and signs (impurities, consistency, odour) characteristic of municipal sewage sludge. It is noted that the accumulation level of anthropogenic organic carbon is comparable to that of organic matter in the bottom sediments of Sevastopol region bays characterized by limited water exchange and subject to long-term anthropogenic pollution. Exceeding the previously established critical organic carbon levels in the soft soils of the Black Sea (Corg ≥ 2.5 %) results in destructive changes in ecosystems: it has a negative impact on benthos sharply changing its structural characteristics (abundance, biomass, total species richness) with restructuring of its dominant species structure.