Hydrochemical features of the Mzymta River catchment area

The chemical composition of rivers is determined by catchment basin features, climatic conditions and anthropogenic influence. This study is devoted to the identification of the main natural and anthropogenic factors and patterns that determine the formation of the chemical composition of the Mzymta River and its tributaries in its middle and lower reaches. Data on hydrochemical parameters, content of biogenic compounds and trace elements, including heavy metals of the Mzymta River and its tributaries from the confluence of the Pslukh River with the Mzymta River to the confluence with the Black Sea, are presented. The result revealed that the lower reaches were characterised by higher concentrations of all nutrient compounds than the middle reaches. A group of trace elements (V, Al, Ti, Mn, Fe, Co, Cu, Pb and REE) whose concentrations have unidirectional changes as the waters move downstream has been identified. The waters of the Pslukh River and the Mzymta River in the area of its confluence with the Pslukh and Kepsha Rivers, as well as in the zone of influence of sewage and its estuary, are significantly enriched in trace elements relative to the median chemical constituents of river waters. In general, changes in the chemical composition of the Mzymta River are influenced by two factors, natural and anthropogenic, namely due to the different geological conditions of its main tributaries, the regime and gradient of the river in its middle and lower reaches and the impact of construction works in the river channels and wastewater discharge.

1. Kostyleva A.V. Distribution of dissolved organic carbon in river mouth areas of the greater Sochi region (North‐Eastern part of the Black Sea). Oceanology, 2015, vol. 55, no. 2, pp. 224–230. (In Russian) https://doi.org/10.7868/S0030157415020082

2. Litvinenko Yu.S., Zakharikhina L.V. Geochemistry and radioecology of waters and bottom sediments of the Mzymta River, the Black Sea coast. Geochemistry international, 2022, vol. 67, no. 4, pp. 376–393. (In Russian) https://doi.org/10.31857/S0016752522030049

3. Makkaveev P.N., Zavyalov P.O. Geokhimiya rechnogo stoka v Chernoe more. Glava 3.2 Stok malykh i srednikh rek rossiiskogo poberezhya Chernogo morya i ego vliyanie na kharakteristiki vod [Geochemistry of river runoff into the Black Sea. Chapter 3.2 Runoff of small and medium‐sized rivers of the Russian Black Sea coast and its influence on water characteristics]. Moscow, Nauchny Mir Publ., 2018, pp. 287–321. (In Russian)

4. Savenko A.V., Pokrovskii O.S. Transformation of Major and Trace Element Composition of the Dissolved Matter Runoff in the Mouths of Medium and Small Rivers of the Black Sea Coast of Russia. Oceanology, 2022, vol. 62, no. 3, pp. 380–402. https://doi.org/10.31857/S003015742203011X (In Russian)

5. Makkaveev P.N., Polukhin A.A., Stepanova S.V. Studies of the estuaries of small and medium‐sized rivers in the coastal zone of the Russian sector of the Black Sea. In: Ekologicheskaya bezopasnost pribrezhnoi i shelfovoi zon i kompleksnoe ispol'zovanie resursov shelfa [Environmental safety of coastal and shelf zones and integrated utilisation of shelf resources]. 2013, pp. 412–417. (In Russian)

6. Savenko A.V., Savenko V.S. Trace Element Composition of the Dissolved Matter Runoff of the Russian Arctic Rivers. Water, 2024, vol. 16, no. 4 (565). https://doi.org/10.3390/w16040565

7. Savenko A.V., Savenko V.S., Efimov V.A., Pokrovskii O.S. Trace element composition of the waters of the Kolyma River mouth section. Doklady Earth Sciences. 2023, vol. 509, no. 2, pp. 272–275. (In Russian) https://doi.org/10.31857/S2686739722602800

8. Komarov R.S., Reshetnyak O.S. Spatiotemporal variability of ion flux in the Kuban River basin. Geology and Geophysics of the South of Russia. 2024, vol. 14, no. 3, pp. 191–203. (In Russian) https://doi.org/10.46698/q44917472‐5566‐w

9. Shesterkina N.M., Shesterkin V.P. Trace elements in the river waters of the coast of the Tatar Strait (eastern macroslope of the northern SikhoteAlin). Vestnik of Saint Petersburg University. Earth Sciences. 2024, vol. 69, no. 3, pp. 509–527. (In Russian) https://doi.org/10.21638/spbu07.2024.307

10. Sharma M.K., Kumar P., Prajapati P., Bhanot K., Wadhwa U., Tomar G., Goyal R.K., Prasad B., Sharma B. Study of hydrochemical and geochemical characteristics and solute fluxes in Upper Ganga Basin, India. Journal of Asian Earth Sciences: X. 2022, vol. 8, article number: 100108. https://doi.org/10.1016/j.jaesx.2022.100108

11. Lesnikova P. S. Changes in the Macroelemental Composition of River Waters in Contrast Geological Conditions, Sochi River of the Black Sea Coast of Russia. Proceedings of VSU, Series: Geography. Geoecology, 2023, no. 3, pp. 47–56. (In Russian) https://doi.org/10.17308/geo/16090683/2023/3/47‐56

12. Durán A.V., Velasquez J.L., Neculqueo G., Deckart K., Lillo D.D., Frez L.N., Trogger D., Quezada A.C., Solé M.B., Escobar M.E. Extreme climatic events in northern Chile and their impact on the geochemical composition of the Huasco River. Journal of South American Earth Sciences, 2022, vol. 118, article number: 103927. https://doi.org/10.1016/j.jsames.2022.103927

13. Huang L., Luo Q., Wei G., Jia Z., Sun K., Zhao C., Yang M., Fang H., Fan Z., Zeng F. Different impacts of natural and anthropogenic factors on dissolved organic matter chemistry in coastal rivers: Implications for water management. Journal of Environmental Management, 2024, vol. 368, article number: 122236. https://doi.org/10.1016/j.jenvman.2024.122236

14. Ansari A.J., Sen I.S., Sinha R. Trends of water composition and discharge in the Ramganga River, Ganga Basin over the last 40 years signal enhanced nitrate flux. Journal of Hydrology, 2024, vol. 641, article number: 131822. https://doi.org/10.1016/j.jhydrol.2024.131822

15. Liu Y., Su B., Mu H., Zhang Y., Chen L., Wu B. Effects of point and nonpoint source pollution on urban rivers: From the perspective of pollutant composition and toxicity. Journal of Hazardous Materials, 2023, vol. 460, article number: 132441. https://doi.org/10.1016/j.jhazmat.2023.132441

16. Basnet N., Sitaula S., Bohara R., Bhattarai S., Rawal S., Uprety M.P., Awasthi M.P., Varol M., Kayastha S.P., Pant R.R. Hydro‐chemical characteristics of Biring and Tangting Rivers (Nepal) and evaluation of water quality for drinking and irrigation purposes. Environmental Research, 2024, vol. 261, article number: 119697. https://doi.org/10.1016/j.envres.2024.119697

17. Dippong T., Török Iu., Tănăselia C., Resz M‐A. Impact of water and sediment pollution in Valea Viseu river, Romania. Process Safety and Environmental Protection, 2025, vol. 195, article number: 106796. https://doi.org/10.1016/j.psep.2025.106796

18. Ali G., Chaudhari M.P., Syed S., Rajpurohit D., Sanyal M., Shrivastav P.S., Hydrogeochemical investigation and water quality assessment of the Indus River in the semiarid region of Ladakh, India. Marine Pollution Bulletin, 2025, vol. 211, article number: 117413. https://doi.org/10.1016/j.marpolbul.2024.117413

19. Trinh D.A., Do N.T., Panizzo V.N., McGowan S., Salgado J., Large A.R., Henderson A.C., Vu T.T. Anthropogenic impacts on the water chemistry of a transboundary river system in Southeast Asia. Journal of Asian Earth Sciences: X, 2024, vol. 12, article number: 100183. https://doi.org/10.1016/j.jaesx.2024.100183

20. Zavyalov P.O., Makkaveev P.N., Konovalov B.V., Osadchiev A.A., Khlebopashev P.V., Pelevin V.V., Grabovskii A.B., Izhitskii A.S., Goncharenko I.V., Solov'ev D.M., Polukhin A.A. Hydrophysical and hydrochemical characteristics of the sea areas adjacent to the estuaries of small rivers of the Russian coast of the Black Sea. Oceanology, 2014, vol. 54, no. 3, pp. 293–308. (In Russian) https://doi.org/10.7868/S0030157414030150

21. Gazeev V.M., Gurbanov A.G., Kondrashov I.A. Paleogenic basalttrachytic formation of west caucasus: geochemical specialization, question of petrogenesis, geodynamic typisation, metallogeny. Geology and Geophysics of the South of Russia, 2018, no. 4, pp. 18–32. (In Russian) https://doi.org/10.23671/VNC.2018.4.20131

22. Prutskii N.I. Karta poleznykh iskopaemykh: K‐37‐V. Gosudarstvennaya geologicheskaya karta Rossiiskoi Federatsii. Novaya seriya. Karta poleznykh iskopaemykh. Kavkazskaya seriya, masshtab: 1:200000. [Mineral map: K‐37‐ V. State Geological Map of the Russian Federation. New series. Map of Mineral Resources. Caucasian series, scale: 1:200000]. FGUGP Kavkazgeolsemka, 2001. Available at: https://www.geokniga.org/maps/32454 (accessed 08.07.2024)

23. Borevskii B.V., Ershov G.E., Kuvykina Yu.Yu. Conditions of formation of operational reserves of Nizhnemzymtinskoye fresh groundwater deposit on the Black Sea coast of the Caucasus and their spatial and temporal changes under the influence of intensive anthropogenic load. Geoekologiya. Inzhenernaya geologiya, gidrogeologiya, geokriologiya [Geoecology. Engineering geology, hydrogeology, geocryology]. 2012, no. 6, pp. 507–519. (In Russian)

24. Lesnikova P.S., Zakharikhina L.V., Litvinenko Yu.S., Shevelev S.G., Vareldzhyan G.V. Geochemistry of Spring Water of Mzymta and Sochi River Basins, Southern Slopeof the Caucasus Ridge. Izvestiya rossiiskoi akademii nauk. Seriya geograficheskaya, 2023, vol. 87, no. 8, pp. 1258–1274. (In Russian) https://doi.org/10.31857/S258755662308010

25. Karelina E.V., Markov V.E., Blokov V.I. Prospectivity of Krasnopolyansky district in Sochi (Russia) for precious metal mineralization. RUDN Journal of Engineering Research, 2017, vol. 18, no. 4, pp. 497–504. (In Russian) https://doi.org/10.22363/2312‐8143‐2017‐18‐4‐497‐504

26. Dzhaoshvili S. Reki Chernogo morya [Rivers of the Black Sea]. Technical Report No. 71. European Environment Agency, 2002, 58 p. (In Russian)

27. Tsomaya V.Sh. Resursy poverkhnostnykh vod SSSR. Tom 9. Zakavkazie i Dagestan. Vypusk 1. Zapadnoe Zakavkaz'e. Gidrograficheskoe opisanie rek i ozer [Surface water resources of the USSR. Volume 9. Transcaucasia and Dagestan. Issue 1. Western Transcaucasia. Hydrographic description of rivers and lakes]. Leningrad, Gidrometeoizdat Publ., 1974, 578 p. (In Russian)

28. Sapozhnikov V.V. Rukovodstvo po khimicheskomu analizu morskikh i presnykh vod pri ekologicheskom monitoringe rybokhozyaistvennykh vodoemov i perspektivnykh dlya promysla raionov Mirovogo okeana [Guidelines for chemical analysis of marine and fresh waters in environmental monitoring of fishery reservoirs and prospective areas of the World Ocean]. Moscow, VNIRO Publ., 2003, 202 p. (In Russian)

29. Rukovodstvo po khimicheskomu analizu poverkhnostnykh vod sushi [Manual on chemical analysis of surface waters of land]. Leningrad, Gidrometeoizdat Publ., 1977, 541 p. (In Russian)

30. Dickson A.G., Sabine C.L., Christian J.R. Guide to best practices for ocean CO2 measurements. PICES Special Publication 3. IOCCP Report, 2007, no. 8, 196 p.

31. RD 52.24. 405‐2018. Mass concentration of sulphates in waters. Methodology of measurements by turbidimetric method. Rostov‐on‐Don: Roshydromet, FGBU «GCI», 2018, 30 p. (In Russian)

32. Nguyen D.V., Nguyen A.B., Hoang T. H. Dissolved Oxygen as an Indicator for Eutrophication in Freshwater Lakes. Environmental Engineering and Management for Sustainable Development, International Conference, Proceedings, 2016, no. 47.

33. Kannel P.R, Lee S., Khan S.P. Application of water quality indices and dissolved oxygen as indicators for river water classification and urban impact assessment. Environmental Monitoring and Assessment, 2007, vol. 132, no. 1–3, pp. 93–110. https://doi.org/10.1007/s10661‐006‐9505‐1

34. Yang X., Wu X., Hao H., He Z. Mechanisms and assessment of water eutrophication. Journal of Zhejiang University Science B, 2008, pp. 197–209. https://doi.org/10.1631/jzus.B0710626

35. Addy K., Green L. Dissolved Oxygen and Temperature. Natural Resources Facts. Fact Sheet, 1997, no. 96–3.

36. Mackey K.R.M., Chien Ch., Post A.F., Saito M.A. Paytan A. Rapid and gradual modes of aerosol trace metal dissolution in seawater. Frontiers in Microbiology, 2015, vol. 5, article number: 794. https://doi.org/10.3389/fmicb.2014.00794

37. Dubinin A.V. Geokhimiya redkozemelnykh elementov v okeane [Geochemistry of rare earth elements in the ocean]. Moscow, Nauka Publ., 2006, 360 p. (In Russian)

38. Chudaev O.V., Chelnokov G.A., Bragin I.V., Kharitonova N.A., Rychagov S.N., Nuzhdaev A.A., Nuzhdaev I.A. Geochemical peculiarities of distribution of major and rare earth elements in the Paratun and Bolshebanna hydrothermal systems of Kamchatka. Tikhookeanskaya geologiya [Pacific Geology]. 2016, vol. 35, no. 6, pp. 102–119. (In Russian)

39. Kharitonova N.A., Filimonova E.A., Kortunov E.A., Samartsev V.N., Drobyazko E.V., Sorokoumova Ya.V., Grechushnikova M.G., Proshkina A.L., Pozdnyakov S.P. Isotope‐geochemical characteristics of natural waters in the southwestern part of the Crimean Peninsula. Water resources, 2022, vol. 49, no. 4, pp. 474–491. (In Russian) https://doi.org/10.31857/S0321059622040095

40. Petrenko D.B., Erofeeva K.G., Okina O.I. Rare earth elements in the environment: concentrations, migration characteristics and methods of determination (review). Theoretical and applied ecology, 2022, no 1, pp. 6–16. (In Russian) https://doi.org/10.25750/1995‐4301‐2022‐1‐006‐016

41. Vetoshkina A.V., Chekryzhov I.Yu., Panichev A.M. Vakh E.A., Baranovskaya N.V., Lutsenko T.N. Radioactive (Th, U) and rare earth elements in natural waters of central Sikhote‐Alin (Primorsky Krai). Bulletin of the Tomsk polytechnic university. Geo assets engineering, 2022, vol. 333, no. 1, pp. 45–56. (In Russian) https://doi.org/10.18799/24131830/2022/1/3408

42. Romanova T.I., Korotkov M.G., Korzhov Yu.V. Prevalence of rare earth elements in natural waters of Khanty‐Mansiysk. Bulletin of the Tomsk polytechnic university. Geo assets engineering, 2024. vol. 335, no. 7, pp. 20–32. (In Russian) https://doi.org/10.18799/24131830/2024/7/4546

43. Lafrenière M., Lapierre, J., Ponton D.E., Guillemette F., Amyot M. Rare earth elements (REEs) behavior in a large river across a geological and anthropogenic gradient. Geochimica et Cosmochimica Acta, 2023, vol. 353, pp. 129–141. https://doi.org/10.1016/j.gca.2023.05.019