Remote evaluation of gold placer mining impact on river water quality

In the Far Eastern region of Russia, due to remoteness, territorial vastness and weak infrastructural development, it is particularly important to use remote sensing to detect and evaluate environmental impact of anthropogenic activities. This article describes the studies aimed evaluation of river water quality in the influence zones of gold placer mining using the mathematical analysis of time series of test indicators and by synthesizing Sentinel-2 satellite images. A regression model is developed for the prediction of water silt content in hard-to-reach places. The object of study is the natural-and-technical system in the south of the Russian Far East, including the Blagodatnoe cluster of placers. Samples of river water and soil were taken for the research. The chemistry and water silt content of the samples were tested in laboratory. It was found that 47% of the test water samples had a silt content higher than the average value over the test region. A procedure is elaborated, which allows remote evaluation of river water quality in the influence zone of gold placer mining. It is revealed that gold placer mining in the Bolshaya Ussurka river basin greatly contributes to build-up of water silt content. Normalization of this indicator takes place through mixing of this river with water of rivers flowing into it. Reduction of water silt content requires undertaking water clarification activities.

Ozaryan Yu. A., Kozhevnikova T. A., Okladnikov V. E. Remote evaluation of gold placer mining impact on river water quality. MIAB. Mining Inf. Anal. Bull. 2025;(12):91-101. [In Russ]. DOI: 10.25018/0236_1493_2025_12_0_91.

The study was supported by the Russian Science Foundation, Grant No. 24-11-20029, https://rscf.ru/project/24-11-20029/, and by the Government of the Khabarovsk Krai, Agreement No. 107С/2024 dated July 31, 2024, and using resources of the Shared-Use Center for Minerals Research of the Far Eastern Branch of the Russian Academy of Sciences, supported by the Ministry of Science and Higher Education of the Russian Federation under Agreement No. 075-15-2025-621.

Yu.A. Ozaryan, Cand. Sci. (Eng.), Leading Researcher, Institute of Mining of the Far Eastern Branch of the Russian Academy of Sciences (IGD FEB RAS), 680000, Khabarovsk, Russia, e-mail: ozaryanigd@gmail.com, ORCID ID: 0000-0002-8892-4595,
T.A. Kozhevnikova¹, Researcher, e-mail: ktvsl@mail.ru, ORCID ID: 0000-0002-2660-3104,
V.E. Okladnikov¹, Engineer, e-mail: okladnikov03@mail.ru,
¹ Computing Center of the Far Eastern Branch of the Russian Academy of Sciences (CC FEB RAS), 680000, Khabarovsk, Russia.

Yu.A. Ozaryan, e-mail: ozaryanigd@gmail.com.

1. Medvedev E. I., Molchanov V. P., Khomich V. G. Palladium-containing gold, magnetite and shorlomite microspherules from placers of the Blagodatnensky cluster (Primorye) and their possible sources. Russian Journal of Pacific geology. 2006, vol. 25, no. 4, pp. 92—96. [In Russ].

2. Molchanov V. P., Khomich V. G., Medvedev E. I. Indicator value of Pd-containing gold from placers of the Blagodatnensky cluster (Primorye). Proceedings of higher educational establishments. Geology and exploration. 2004, no. 3, pp. 36—38. [In Russ].

3. Nevolin P. L., Mitrokhin A. N., Utkin V. P. Sikhote-Alin folded system: general structural features and some aspects of gold mineralization control (using the Central Sikhote-Alin as an example) (part two). Bulletin of the Kamchatka regional association «Educational-scientific Center». Series: Earth Sciences. 2018, no. 3(39), pp. 74—89. [In Russ]. DOI: 10.31431/1816-5524-2018-3-39-74-89.

4. Ozaryan Yu. A. Remote sensing of vegetation restoration in mining areas of the southern Far East. Gornyi Zhurnal. 2024, no. 6, pp. 105—109. [In Russ]. DOI: 10.17580/gzh.2024.06.17.

5. Masocha M., Dube T., Mambwe M., Mushore T. D. Predicting pollutant concentrations in rivers exposed to alluvial gold mining in Mazowe Catchment, Zimbabwe. Physics and Chemistry of the Earth, Parts A/B/C. 2019, vol. 112, pp. 210—215.

6. Ayiwouo M. N., Yamgouot F. N., Mambou L. L. N., Kingni S. T., Ngounouno I. Impact of gold mining on the water quality of the Lom River, Gankombol, Cameroon. Heliyon. 2022, vol. 8, no. 12.

7. Boussouga Y. A., Sacher F., Schäfer A. I. Water quality of the Gambia River: A prospective drinking water supply. Science of the Total Environment. 2023, vol. 878, article 162794. DOI: 10. 1016/j.scitotenv.2023.162794.

8. Eniowo O. D. When closure fails: Uncovering the environmental impact of gold rewashing on abandoned mine sites in Southwestern Nigeria. World Development Perspectives. 2025, vol. 38, article 100682. DOI: 10.1016/j.wdp.2025.100682.

9. Taskaeva A. I., Pakusina A. P. Changes in water quality during gold mining in small rivers. Ekologiya rechnykh basseynov: Trudy 11-y Mezhdunarodnoy nauchno-prakticheskoy konferentsii [Ecology of River basins: Proceedings of the 11th International Scientific and Practical Conference], Vladimir, 2023, pp. 657. [In Russ].

10. Tikhomirov O. A. Bocharov A. V., Komissarov A. B., Khizhnyak S. D., Pakhomov, P. M. Using Landsat 8 (OLI) sensor data to assess turbidity, color, and chlorophyll content in the water of the Ivankovskoye Reservoir. Vestnic TVGU. Series «Khimiya». 2016, no. 2, pp. 230—244. [In Russ].

11. Innokentyev A. I., Shkolny D. I., Prokopyeva K. N. Assessing the impact of mineral development on water turbidity based on satellite data. Materialy 22-y Mezhdunarodnoy konferentsii «Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa» [Proceedings of the 22nd International Conference «Modern Problems of Remote Sensing of the Earth from Space»], Moscow, 2024, p. 382. [In Russ]. DOI: 10.21046/22DZZconf-2024a.

12. Yanin E. P. Environmental consequences of placer deposit development. Review. Problems of environment and natural resources. 2019, no. 7, pp. 10—54. [In Russ].

13. Pakusina A. P., Taskaeva A. I., Gulenova T. V. Chemical and ecological characteristics of small rivers and wetlands of the Amur region. Izuchenie vodnykh i nazemnykh ekosistem: istoriya i sovremennost'. Tezisy dokladov 3-y Mezhdunarodnoy nauchno-prakticheskoy konferentsii [Study of aquatic and terrestrial ecosystems: history and modernity. Abstracts of the 3rd International Scientific and Practical Conference], Sevastopol, 2024, pp. 223—224. [In Russ].

14. Ushakov M. V. Calculation of rainfall flood recession curves for managing the hydroecological situation on the rivers of the Northern Sea of Okhotsk. Geographical environment and living systems. 2020, no. 1, pp. 126—133. [In Russ].

15. Novikov Yu. V., Sayfutdinov M. M. Voda i zhizn' na Zemle [Geographical environment and living systems], Moscow, Nauka, 1981, 184 p.

16. Ushakov M. V. Moisture regime in the Kolyma basin under climate change conditions. Society. Environment. Development. 2023, no. 2 (67), pp. 170—173. [In Russ].

17. Shulkin V. M., Bogdanova N. N., Elovsky E. V. Influence of filter colmatation on the determination of the concentration of truly dissolved and colloidal forms of migration of chemical elements in river waters. Water resources. 2022, vol. 49, no. 1, pp. 91. [In Russ].

18. Shkolnyi D., Magritsky D., Chalov S. Impact of open-cast placer mining on sediment transport across Far Eastern rivers of Russia. International Journal of Sediment Research. 2024, vol. 39, no. 5, pp. 702—713. DOI: 10.1016/j.ijsrc.2024.03.001.

19. Shkolnyi D., Magritsky D., Chalov S. Impact of open-cast placer mining on sediment transport across Far Eastern rivers of Russia. Earth science and subsoil use : Earth science and subsoil use. 2021, vol. 44, no. 4 (77), pp. 471—484. [In Russ].

20. Yanin E. P., Kuzmich V. N., Ivanitsky O. M. Regional natural heterogeneity of the chemical composition of surface waters on land and the need to take it into account when assessing their ecological state and the intensity of technogenic impact. Problemy okruzhayushchey sredy i prirodnykh resursov. 2016, no. 6, pp. 3—72. [In Russ].