Pollution history of Neva Bay bottom sediments (eastern Gulf of Finland, Baltic Sea)

Abstract

Neva Bay is the shallowest and easternmost part of the Gulf of Finland (Baltic Sea). St. Petersburg, Russia's second largest city, occupies the coastal area where the Neva River debouches into Neva Bay. St. Petersburg has a protracted history of industrial, transportation and urban related activity that have affected Neva Bay. By the sealing off the bay from the eastern Gulf of Finland, the St. Petersburg Flood Protective Facility, which was constructed from the 1970's to 2011, transformed Neva Bay into a "technogenic" lagoon. Neva Bay sediments record a unique history of pollution near the metropolis. Heavy metal concentrations of most elements studied varied consistently throughout sediment cores. Temporal trends indicate that metals started to accumulate abruptly in the first half of the 20th century. Zinc, lead and copper were the first metals to reach contaminant thresholds implicating the regional base metal industry as a source. Significant increase in cadmium levels a decade or two later suggests pollution from the regional chemical industry. th and 21 st century scientific surveys reveal dramatic shifts in Neva Bay sedimentation processes over the last three centuries. The western part of Neva Bay has transitioned from a sanddominated system to one of mud accumulation with the aerial extent of mud deposition expanding significantly during the 20 th century. This inventory coupled with an understanding of primary natural and anthropogenic processes can help inform decision makers to support the overall ecological health of the bay.

Experimental studies of benthos resistance to mechanical burying under the dredging material

“…The resistance of benthic hydrobionts to impact depends not only from the biological peculiarities of different species, but also from specific biotope, and composition of dredging material [5,6,[10][11][12][13][14][15].…”

“…There were Chironomidae «bloodworms» Chironomus plumosus, Gastropoda mollusks (marine snails) Melanoides tuberculate, and Oligochaete Tubifex tubifex. All selected objects can be observed as a model of the freshwater component of the EGoF fauna [7][8][9][10]12]. The fauna of the Neva Bay is of the freshwater type [9,10].…”

Long-term monitoring of the dredged material deposit sites in the Eastern Gulf of Finland

“…Field studies in the form of EM UDS program in the Eastern Gulf of Finland and Neva Bay were carried out since 1999 by expert team specialists [1][2][3][4][5][6][7][8][9][10]12]. The measurements of oceanographic parameters were made:…”

“…On the base of the results of investigations, which took place during 20 years in the coastal zone of the Eastern Gulf of Finland (Baltic Sea) and Neva Bay, the environmental effects of the dumping of the dredged material on the ecosystems of the underwater bottom deposit sites were analysed. In 1999-2019 the program of the Ecological Monitoring of Underwater Deposit Sites (EM UDS) for the Eastern Gulf of Finland and Neva Bay was developed and used [1][2][3][4][5][6][7][8][9]. Principal questions and goals of the EM UDS are: (1) revealing of the short-and long-term environmental effects of the dumping of the dredged material, and establishing the difference between the natural and anthropogenic trends of the coastal ecosystems near the dredged material deposit sites; (2) estimation of reversibility / irreversibility of trends and changes in coastal ecosystems due to influence of the dumping of dredged material; (3) finding the ways of minimizing and compensation of negative effects on the coastal environment [3,4,[10][11][12][13][14][15].…”

The supply of total nitrogen and total phosphorus from small urban catchments into the Gulf of Gdańsk

“…Research on marine sediments also indicates a strong eutrophication of the Baltic Sea caused by man (Warnock et al 2018). The influence of bottom sediments on the quality of the Baltic Sea was also described by Vallius (2016) or Ryabchuk et al (2017). Climate disturbances are extremely important in the aspect of emerging extreme phenomena.…”