ZINC AND LEAD ACCUMULATION BY FUCUS DISTICHUS (FUCALES) IN COASTAL WATERS OF SOUTHEASTERN KAMCHATKA AND COMMANDER ISLANDS DURING 2000-2020 Liliya A. Pozolotina, Anna V. Klimova, Nina G. Klochkova Kamchatka State Technical University , Petropavlovsk-Kamchatsky, Russian Federation INTRODUCTION In the Far Eastern seas of Russia, Fucus distichus Linnaeus (1767) is widespread and dominant species of macrophytes in the littoral zone (Fig. 1). This fucoid can withstand long-term exposure to different contaminants (heavy metals, petroleum hydrocarbons, phenols) and is a biomonitor of environmental pollution In the Far Eastern seas of Russia. The aim of this study was to determine changes in the content of zinc (Zn) and lead (Pb) in F. distichus of Avacha Bay (southeastern Kamchatka) and Bering Island (Commander Islands) for twenty years. Avacha Bay is an anthropogenic impact area, Bering Island is a protected area, where the negative impact of human activity is minimal (Fig. 2). Figure 1. Plants of Fucus distichus in the coastal areas of Avacha Bay (southeastern Kamchatka) MATERIALS AND METHODS Avachinsky Fucus distichus recognized as an environmental pollution monitor Inlet species. Samples of algae were collected in the period 2000-2020. The material was carried out in the coastal areas of Avacha Bay and Bering Commander Islands Island (Commander Islands) (Fig. 2). The quantitative content of Zn and Pb was determined by the method of acid digestion of samples and the subsequent determination of the content of metals by the spectrochemical method. The generalization and processing of the obtained data was carried out by statistical methods. Concentration of Zn (Me±95SI) Concentration of Zn: Zn: 2016-2020 50 2000-2020 34.1 Figure 2. Location of the coastal sample sites. (A) Map of Avacha Bay 150 150 (Avachinsky Inlet), (B) Map of Bering Island (Commander Islands) 40 100 30 100 50.2 39.7 33.4 mg/kg mg/kg 20 mg/kg 50 RESULTS AND DISCUSSION 50 10 no data 0 0 0 Over the entire period, the Zn content in F. distichus varied in the 2016 2017 2018 2019 2020 2000- 2011- 2000- 2011- range of 11.6-140.4 /g dw in Avacha Bay and 7.8-21.3 /g dw for 2010 2020 2010 2020 Avacha Bay Bering Is Avacha Bay Bering Islands Avacha bay Bering Is (Fig. 3). Over a twenty-year period, there has been an increase Concentration of Pb: Concentration of Pb (Me±95SI) μg μg 2000-2020 Pb: 2016-2020 in its content in from all the studied areas. The Pb content in 6 F. distichus 15 15 4.5 F.distichus for the entire period of research varied in the range of 0.5-13.2 4 /g dw in Avacha Bay and 0.4-5.1 /g dw for Bering Is. During 2000- 10 10 3.9 gg mg/kg 2020, the accumulation of Pb by F. distichus decreased. In the period mg/kg 3.5 μg μg 2 5 5 1.9 2000-2010, the concentration ranges of Zn in the F. distichus of the Avacha no data 0 0 0 Bay and Bering Is. was comparable. In the last decade, significant 2000- 2011- 2000- 2011- 2016 2017 2018 2019 2020 2010 2020 2010 2020 differences have been observed in the accumulation of these metals by Avacha Bay Avacha Bay Bering0 Islands0 Bering Is 0 0 Avacha bay F.distichus of Avacha Bay and Bering Is. Figure 3. Dynamics of Zn and Pb content in Fucus distichus during 2000- 2020. Algological material was collected in the coastal areas of Avacha Bay and Bering Island CONCLUSION The presented study of the Zn and Pb accumulation over two decades in the brown algae Fucus distichus (Fucales) showed the dependence of the accumulation of heavy metals on the growing place of the monitor species. Avacha Bay is characterized as an anthropogenic impact area. In F. distichus from Avacha Bay the maximum Zn content was seven times higher than the metal content in algae from the coastal areas of Bering Island. Similarly, the maximum Pb content in the analyzed material from Avacha Bay was more than two and a half times more than from the protected area of Bering Island, where the negative impact of human activity is minimal..