Polymetallic Ore Mining Impact Assessment on the Benthic Hydrobiocenosis of the Small Estuaries on the Arctic Islands

Abstract

The results of studies on the content of aluminum and heavy metals in benthic sediments and algae in the estuaries of the Arctic island Vaygach are presented. This island is located on the Barents and Kara Sea border, and it is part of the Pay-Khoi ridge which can be called a “continuation” of the Ural Mountains to the north. The observations were conducted in Krasnaya and Varkulyakha Rivers located in the island’s southern part and flow into the Yugorsky Shar Strait. Krasnaya River is located near a polymetallic ore deposit, which was developed in 1931–1934. Reconnaissance fieldwork was carried out in the river estuaries through measurements of salinity and water level. Measurements of the mass concentration of elements in the studied samples of sediments and algae were carried out by atomic emission spectrometry. The preparation of plant samples was by microwave decomposition, and that for samples of bottom sediments was carried out by acid decomposition in an open manner. The obtained concentration samples were compared using “Tukey exploratory data analysis (EDA)”. The presence of anomalies in the high content of copper, manganese, and zinc in filamentous algae at the control site in the Krasnaya River estuary was revealed. For some elements, the enrichment index was calculated relative to the upper part of the earth’s crust content. It is assumed that the occurrence of this situation is due to the long-term consequences of mining polymetallic ores. The accumulation of metals in river estuaries may be related to the observed warming of the climate in the western sector of the Arctic region.

1. Introduction

The observed warming of the Arctic region in recent decades [1] opens up great prospects for the development of its mineral resources [2], including polymetallic ores on the Arctic islands. At the same time, many heavy metals in such ores can pose a serious danger to aquatic flora and fauna if they enter rivers and seas [3,4]. The significant vulnerability of Arctic ecosystems to man-made impacts entails the necessity for developing special environmental measures. Solving this problem requires a large amount of research on the specifics of migration of toxic metals in the natural environment of the Arctic islands. Unfortunately, the number of field studies of the ecosystems of the Arctic islands is very limited due to the inaccessibility of their territories and the high cost of fieldwork on such islands. In this situation, any observations within the framework of the problem raised will undoubtedly be useful for the rational and environmentally safe development of the mineral resources of the Arctic islands [5].

Currently, gold mining is underway in the territory of Russia on Bolshevik Island of the Severnaya Zemlya archipelago in the Laptev Sea, and a lead–zinc ore deposit is being prepared for development on Yuzhny Island of the Novaya Zemlya archipelago. However, even in the period of 1931–1934, lead–zinc ores were mined in the south-west of Vaygach Island in the Barents Sea. Its volume amounted to about 11 TMT of ore [6]. In 1935, ore mining was stopped due to the flooding of the mines with groundwater. In all probability, these were the consequences of short-term climate warming in the western sector of the Russian Arctic region, observed in the 1920s–1940s [7]. During the period, an attempt was also made to develop a copper ore deposit in the north of Vaygach Island. The extraction of these ores was carried out without observing any environmental measures.

In other countries, the development of deposits of various metals on the Arctic islands began in the second half of the twentieth century. Polymetallic ore mining has been mostly developed on the island of Greenland. Eleven million metric tons of lead–zinc ores were mined here at the Black Angel deposit in the period of 1973–1990 [8]. In some years, molybdenum and gold mining was also carried out on this island.

The transfer of metals from mining sites in the catchments of Arctic rivers occurs through the estuaries of rivers of various types. Estuaries of rivers, as particularly complex hydrologically, hydrochemically, and hydrobiologically water bodies, attract the attention of many researchers. The main issues of formation, typification, and zoning of estuaries of rivers in Russia have been studied relatively well [9]. However, the estuaries of its southern territories are the most studied. Modern knowledge about the estuaries of Arctic rivers is mainly based on studies of several large hydrographic systems [10,11,12]. The studies of the estuaries of small rivers carried out in the north were carried out mainly on the mainland coast in the European part of Russia, mainly on the White Sea [13,14,15]. There are a number of works on the specifics of natural processes in the estuaries of small rivers outside Russia, for example, the article [16].

Practically no works have been carried out to study the processes occurring in the estuaries of small rivers of the Arctic islands, the Kara Sea, the Laptev Sea, and the East Siberian Sea. On the other hand, the available data suggest that the processes in the estuaries of small rivers occur in a completely different way than in medium and large rivers [15].

The ecosystems of the rivers of the Arctic territories are very sensitive to various types of climatic influences. First, this can be traced to the flow of rivers [17]. It was established in [18] that the degradation of permafrost led to an increase in the removal of carbonates, nitrogen, and phosphorus by rivers into the seas. Therefore, studying the processes of the estuarine marginal filter is an important prerequisite for understanding the potential climate feedback associated with the release of freshwater and carbon [12]. A quantitative assessment of the contribution of river runoff to the removal of matter into the sea is important for determining the effects of climate warming in the Arctic region [19], but the necessary information concerns only the main large Arctic rivers.

The remoteness of the Arctic territories has long provided a certain degree of protection from pollution of their watercourses and reservoirs, but currently, the problem of pollution of Arctic aquatic ecosystems is very acute [20]. The increased impact on Arctic ecosystems is also due to the continued exploitation of its mineral resources, such as oil, gas, gold, and polymetallic ores [21].

In order to understand the nature of such an impact, minimize it, and eliminate possible negative consequences, it is advisable to conduct a more in-depth study of the impact of previously developed mineral deposits. This problem is of particular relevance for the Arctic islands, including in the territory of Russia. As mentioned above, the object of such a study may be the island of Vaygach, which separates the southern regions of the Barents and Kara Seas.

Studies of the state of the ecosystems on the island of Vaygach are limited and fragmentary. Most of the research concerns the study of flora and fauna [22,23,24], including their role as an indicator of atmospheric pollution [25]. In 2010–2012, an assessment of the impacts of climate change and anthropogenic pressure on the ecosystems of Vaygach Island was carried out [26,27], but they did not concern the assessment of the possible consequences of mining polymetallic ores on the island. There are a number of works on the study of surface waters of the Vaygach River, but only lakes were included [28,29]. There are also studies on the distribution of suspended solids in the coastal waters of the island [30] and its soils [31].

The research objective here is identifying possible negative consequences of polymetallic ore production on the Arctic islands, which was carried out many years ago without environmental protection measures.

2. Materials and Methods

2.1. Study Area and Field Observations

To assess the long-term effects of polymetallic ore mining on the ecosystem of Vaygach Island in 2023, specialized studies were conducted on the content of aluminum and heavy metals (manganese, copper, arsenic, nickel, lead, and zinc) in benthic sediments of river estuaries and algae. The observations were carried out at the estuaries of the small Krasnaya and Varkulyakha Rivers flowing into the Yugorsky Shar Strait between the Barents and Kara Seas (Figure 1); they belong to the lagoon type.

The estuary of the Krasnaya River consists of an open estuary with a length of about 1 km, a lagoon about 1.6 km long and 0.7–1 km wide, a funnel-shaped estuary about 1 km long, and an estuary section of the river about 0.8 km long. In the last site, the width of the watercourse becomes constant, and rifts appear. Lead–zinc ores were mined in the catchment area of this river within its estuarine area. In the ore mining area, 2 destroyed mines and 10 trenches with dumps of undelivered ore were found (Figure 2). The estuary of the Krasnaya River was chosen as a control area to assess the consequences of mining lead–zinc ores.

The estuary of the Varkulyakha River also has an open outfall offshore with a length of 1 km, a small lagoon about 0.6 km long and 0.3–0.5 km wide, a small delta about 1.5 km long, and an estuary section of the river about 1.4 km long. The estuary of this river was chosen as a background area for assessing the consequences of mining lead–zinc ores.

The catchments of the Krasnaya and Varkulyakha Rivers touch each other, the distance between their estuaries is about 14 km, and they have the same landscape and sediment texture. Based on the measurement results conducted during fieldwork, in their estuaries, the greatest depths at low tide usually do not exceed 0.5 m, but at the sea borders of lagoons in narrow straits, they reach 2–3 m. The lagoons, estuaries, and river deltas are dominated by silts and silty sand. Sands, gravel, and pebbles with inclusions of stones begin to predominate in the estuaries of rivers, on the sea borders of lagoons, and in the estuaries of rivers. At the peak of the tidal cycle, the estuaries of the rivers under consideration completely occupy the mixing zones of river and sea waters with a salinity of 3–25‰.

So-called microtidal conditions are observed in the estuaries of the Krasnaya and Varkulyakha Rivers [33]. During the period of fieldwork, the tide at the river boundaries of the lagoons ranged between 24 and 33 cm. The water temperature in the peaks of the mouths of the Krasnaya and Varkulyakha Rivers at the end of July 2023, due to abnormally hot weather, reached 18.2–25.2 °C, and at their maritime borders, the temperature reached 15.3–18.2 °C.

2.2. Sample Collection and Analysis

In each estuary, benthic sediment samples were taken at 5 stations separated by a distance of 1 km. The first station was located on the estuary of the river in the Yugorsky Shar Strait, the second station was on the sea border of the lagoon, the third station was in the center of the lagoon, the fourth station was on the river border of the lagoon, and the fifth station was on the estuary section of the river. Algae samples were taken at the second station (fucuses) and the fourth station (filamentous algae).

To measure fluctuations in the water level, water-level scales were used with reference to the conditional zero of the post. Measurements of water temperature and salinity (mineralization) were carried out with a multiparametric liquid analyzer Multi 3420 SET G by Wissenschaftlich-Technische Werkstätten (Munich, Germany). The detection limits (accuracy) were −5.0–105 °C (±1.0 °C) and 0.001–500 mS/cm (±2.5 mS/cm). Calibration to a reference standard was performed every 6 months. The cell constant was determined in the control standard, 0.01 mol/L KCl (E-Set Trace by Wissenschaftlich-Technische Werkstätten (Munich, Germany)).

Benthic sediment samples were taken in the tidal zone of river mouths using a stainless-steel sampler from the surface layer of sediments. Simultaneously with benthic sediment samples, algae samples were taken from 4 out of 10 sites. Their selection was carried out by the method of mowing from sites of 50 cm², for their further analysis in dry weight with complete algae thallomes, given that the brown algae Fucus distichus was represented by a small aberrant shape, and the morphological parts of the thallome did not differ in the green algae Ulva prolifera. Disposable plastic bags were used for sampling and storage of samples.

In the laboratory, the samples were dried in a drying cabinet to an air-dried state, crushed in an agate mortar, and then sifted through a sieve with 1 mm cell size without separating other fractions. The sample weight was 30–100 g.

Measurements of the mass concentration of elements in the studied samples of sediments and algae were carried out using Inductively Coupled Plasma Atomic Emission Spectrometer ICPE-9000 by Shimadzu (Kyoto, Japan), according to the method of (PND F) 16.2.2:2.3.71-2011. The detection limits (accuracy) were as follows: Al—8–400 mg/kg (±42%) and over 400–10,000 mg/kg (±30%), Cu—0.25–10 mg/kg (±40%) and over 10–100 mg/kg (±30%), Zn—1–100 mg/kg (±44%), Pb—0.25–100 mg/kg (±36%), Mn—1–100 mg/kg (±30%) and over 100–2000 mg/kg (±25%), Ni—0.25–10 mg/kg (±42%) and over 10–70 mg/kg (±34%), and As—0.5–5 mg/kg (±50%) and over 5–100 mg/kg (±38%).

The preparation of plant samples was carried out by microwave decomposition, and that for samples of bottom sediments was carried out by acid decomposition in an open manner.

The microwave decomposition method consists of the following steps. At least 0.250 g of sifted sample is weighed onto paper or in a weighing cup, quantitatively transferred to a microwave cup, and 10 cm³ of concentrated nitric acid is added, covered with a watch glass, and left in a fume hood for 2–3 h. Then, about 10 cm³ of bidistilled water is carefully added, the prepared cups are placed in a microwave oven and decomposition is carried out according to the established mode for specific types of samples. Upon decomposition completion, the samples are cooled in closed cups to approximately room temperature. After that, the resulting solution is transferred to a 50 cm³ measuring flask. The cup walls are rinsed with bidistilled water and poured into the same measuring flask while bringing the solution volume to the mark. The resulting solution prepared for analysis is transferred into a plastic test tube. The solution can be filtered with a paper filter if necessary.

The open acid digestion method was used for bottom sediments in a glass beaker on a sand bath. This method consists of the following procedure. The sample is placed in a heat-resistant beaker; nitric acid is added, covered with a watch glass, placed in a sand bath, brought to a boil, and boiled for at least 20 min. Then, 5–10 cm³ of concentrated hydrogen peroxide is added dropwise to the sample while stirring and boiled for another 15–30 min until the solution is completely dissolved. After cooling to room temperature, the solution is transferred to a 50 cm³ measuring flask while bringing the volume up to the mark with bidistilled water. The solution can be filtered with a paper filter if necessary.

Quality control of the measurement results during the experimental process in the laboratory involves a measurement procedure control by assessing the error using reference materials according to “17th Needle/Leaf Interlaboratory test 2014/2015”.

In order to identify the effects of lead–zinc ore mining on aquatic ecosystems, an exploratory analysis procedure developed by the famous mathematician Tukey was used [34,35,36]. It is adapted to studies of very short series of observations and does not depend on the specific type of statistical distribution of the analyzed data. According to the procedure above, the results of observations are presented in the form of a “box-and-whisker” plot, which clearly reflects their statistical structure. It is a rectangle (box), the upper and lower sides of which (folds) correspond to the values of quartiles C_0.25 and C_0.75, and a transverse line inside the box is the median C_m. Next, “whiskers” are attached to the box: segments connecting each fold with extreme values. This structure is complemented by the “Tukey internal barriers”. They are located at a distance of 1.5 interquartile ranges H from the lower and upper quartiles, by capturing 99% of the sample elements in the case of a normal distribution [34]. If the value of interest is above or below the “Tukey internal barriers”, one can conditionally consider it an anomaly, possibly related to anthropogenic influence.

The enrichment index is used to assess the enrichment of sediments, including benthic sediments, with heavy metals:

$$EF=\left({\displaystyle \frac{{El}_{sed}}{{Al}_{sed}}}\right)/\left({\displaystyle \frac{{El}_{bgrnd}}{{Al}_{bgrnd}}}\right)$$

(1)

where El_sed and Al_sed are the contents of the element of interest and aluminum in the studied sediments, respectively, and El_bgrnd and Al_bgrnd are the geochemical background contents of the element and aluminum, respectively [37]. In this work, the average values of the content of heavy metals in the upper part of the earth’s crust were used as a background value.

3. Results

To identify the effects of lead–zinc ore mining on aquatic ecosystems, a statistical analysis of data on pollution of sediments and algae in the estuaries of the Krasnaya and Varkulyakha Rivers was carried out; Figure 3 shows Tukey diagrams of these data.

Table 1. Statistical characteristics of the content of aluminum and heavy metals in the benthic sediments (mg/kg) of the river estuaries of the island of Vaygach in July 2023.

Statistics	Al	As	Cu	Mn	Ni	Pb	Zn
Krasnaya and Varkulyakha Rivers both (N = 10)
Min	610–5400
Average value	2815	1.27	1.01	77.6	4.71	0.36	9.83
Standard deviation	1819	0.61	1.19	70.5	3.57	0.39	7.27
Median	3250	1.10	0.58	50.0	5.25	0.13	10.25
Three-average value	2919	1.18	0.59	54.6	4.92	0.24	9.98
Lower quartile (C25%)	928	0.70	0.20	35.3	1.73	0.13	3.15
Upper quartile (C75%)	4250	1.83	0.99	83.0	7.45	0.59	16.25
Interquartile range (H)	3323	1.13	0.79	47.8	5.73	0.46	13.10
Maximum value	5400	2.10	3.30	210.0	9.10	1.00	19.00
Minimum value	610	0.58	≤0.25	18.0	≤0.25	≤0.25	1.20
Krasnaya River only (N = 5)
Average value	2794	1.15	0.89	78.0	4.41	0.30	9.96
Maximum value	4400	1.90	3.10	200.0	9.10	0.99	19.00
Minimum value	670	0.58	≤0.25	19.0	≤0.25	≤0.25	1.02
Varkulyakha River only (N = 5)
Average value	2836	1.38	1.14	77.2	5.01	0.42	9.70
Maximum value	5400	2.10	3.30	210.0	8.90	1.00	19.00
Minimum value	610	0.60	≤0.25	18.0	≤0.25	≤0.25	1.20
According to data from other sources
Around Novaya Zemlya, Yushin et al. [38]	-	-	5.95–28.37	-	14.07–45.72	9.07–17.39	25.15–84.57
The Chukchi Sea, Sattarova et al. [39]	-	15.90	16.50	-	41.00	15.96	82.70
Spitsbergen, 2007, Perner et al. [40]	-	17–36	-	-	-	180–2325	379–4600

and

Table 2. Statistical characteristics of the content of aluminum and heavy metals in algae (mg/kg) of the river estuaries of the island of Vaygach in July 2023.

Statistics	Al	As	Cu	Mn	Ni	Pb	Zn
Krasnaya and Varkulyakha Rivers both (N = 4)
Average value	1013	8.18	1.47	432.3	4.25	0.83	28.50
Standard deviation	633	5.04	0.72	302.5	0.33	1.05	16.13
Median	1060	7.15	1.25	400.0	4.15	0.40	25.50
Three-average value	1048	7.41	1.31	408.1	4.18	0.51	26.25
Lower quartile (25%)	548	5.05	1.05	294.8	4.00	0.29	18.25
Upper quartile (75%)	1525	10.28	1.68	537.5	4.40	0.95	35.75
Interquartile range	978	5.23	0.63	242.8	0.40	0.66	17.50
Maximum value	1600	15.00	2.50	830.0	4.70	2.40	50.00
Minimum value	330	3.40	0.89	99.0	4.00	≤0.25	13.00
According to data from other sources
The median concentration of elements in algae of different systematic groups, Sánchez-Quiles et al., 2017 [4]	-	13.90	7.43	41.90	4.40	4.60	37.30
MPC *	-	5.0	-	-	-	0.5	-

* The MPC is given following the Technical Regulations of the Customs Union “On Food Safety”, 2021.

present the results of the exploratory data analysis (EDA) in an appendix to the samples of the results of observations in the estuaries of Vaygach Island.

In benthic sediment samples, such values were recorded for manganese and copper in the estuaries of the Varkulyakha River. At the same time, they differed slightly from the maxima of manganese and copper content in the benthic sediments of the control area.

Abnormal values for manganese, copper, and lead are associated with their high concentrations in the thallomes of the green algae Ulva prolifera (=Enteromorpha prolifera), growing on the littoral of the estuary of the Krasnaya River, in the area opposite the ore mine. This species is also an important indicator of water eutrophication and actively absorbs elements. Concentrations exceeded the maxima of their content in the same algae of the estuary of the Varkulyakha River (background area). These samples were taken at the river boundaries of estuarine lagoons, where the hydrological frontal section between fresh and salt waters was localized.

The data analysis in Table 1 shows that the bottom sediments’ heavy metal concentration in the described river estuaries have comparable values. However, the average concentrations of Al, As, Ni, and Pb in the Varkutsyakha River estuary are slightly higher. This situation can be explained by the larger size of the Varkutsyakha catchment area, which increases the rocks’ mass as a metal source in the river waters. In addition, Tukey’s exploratory analysis shows abnormally high (“outlier”) concentrations of manganese and copper in the bottom sediments of this river (Figure 3), probably at the underground water’s discharge points. Nevertheless, they have comparable values with the maximum manganese and copper concentrations in the Krasnaya River estuary’s bottom sediments. For this river, the maximum values do not reach abnormal levels due to the high median value, which indicates a high average level of metal content in the Krasnaya River’s bottom sediments, while the increased content of metals at the Varkutsyakha River estuary is due to local influx, probably from groundwater.

In the algae of the estuaries of the rivers on Vaygach Island, the content of most elements except Al, which is not included in the group of physiologically active microelements of algae, is higher than in benthic sediments (Table 1 and Table 2). A significant excess is observed in terms of the content of Cu, Zn, and Mn in algae compared to benthic sediments.

The average concentrations of arsenic and lead in algae slightly exceed the norms established by the Technical Regulations of the Customs Union [41]: by 1.66 times. At the same time, the maximum values can exceed the maximum permissible values by up to 3–5 times.

For copper and lead, the enrichment factor (EF) values were both one, which indicate a lithogenic source for these elements. For manganese, nickel, and zinc, the EF values correspond to moderate enrichment. Significant enrichment of benthic sediments was noted for arsenic.

4. Discussion

Benthic sediments and algae absorb metals from water, but their accumulation in algae is noticeably more active in most elements compared to sediments, which indicates the selectivity of biological species to absorb elements and, possibly, their use in metabolic processes [42,43]. Marine algae selectively absorb elements from water and partly from bottom sediments. This has been shown for the brown alga Saccharina latissima in the Barents Sea off the coast of the Kola Peninsula [43]. The algae accumulate heavy metals during their entire life cycle and only a small part of them is consumed by cells in metabolic processes. In addition, bottom sediments are an unstable environment for element accumulation, as they are regularly washed by water. This explains the higher content of these elements in algae compared to bottom sediments. Among the algae we studied, Fucus distichus is perennial, while Ulva prolifera is annual. However, the most analyzed element content in Ulva prolifera samples is higher compared to that in Fucus distichus. One of the possible reasons for this is more intense absorption of elements. Ulva prolifera is a nitrophilous species, and its more active absorption of heavy metals can be explained by its adaptation to living in eutrophic water conditions enriched with nitrogen. High concentrations of metals in algae of the estuaries of the island of Vaygach indicate possible contamination of these river estuaries.

There are no maximum permissible concentrations for the content of metals in benthic sediments in the territory of Russia. The norm of lead content in algae according to the Technical Regulations of the Customs Union [40] is 0.5 mg/kg. The recorded extreme of the lead content in algae at the estuary of the Krasnaya River exceeds the above standard by 4.8 times. However, according to the requirements of the European Union countries, where such a norm is 3 mg/kg, and those of the USA, where the norm is 10 mg/kg [44], the accumulation of lead in algae in the estuaries of the Vaygach Island rivers does not pose a threat to human health.

The content of As, Cu, Pb, and Zn in algae of the estuaries of the rivers of Vaygach Island is lower than that in algae of different systematic groups of regions of the World Ocean [44]. According to the literature, a significant excess of As is observed in the brown alga Saccharina latissima living in the Drozdovka Bay of the Barents Sea, where its concentrations in 2003 amounted to 82.0 mg/kg, under conditions of anthropogenic influence on the bay, and 50.49 mg/kg in 2018, after its weakening [42].

Ni concentrations in algae of the studied area are at the level of values for other algae species in different regions [45]. The concentration of Zn, which is the first element of lead–zinc ores in terms of content, also differs slightly.

Attention has been drawn to the relatively low average concentration of Mn in the algae of the World Ocean [44], which is 10 times lower than that in the estuaries of the rivers of the island of Vaygach. Lower concentrations of this element were obtained for brown algae (including Fucus distichus) in the Barents Sea [42,46] and for algae of different systematic groups in the Sea of Japan [43]. Manganese is a macronutrient of the earth’s crust and has a natural origin in the watercourses of Vaygach Island. Its accumulation is observed in the marshy meadows of the intertidal zone [47], which occupy significant areas in the estuaries of the island’s rivers.

The observed situation shows the presence of remote consequences of polymetallic ore mining on the bottom biogeocenosis of the estuary of the Krasnaya River. It could have been formed due to the inflow of highly acidified drainage waters from ore mining sites into the estuary. There are numerous ore dumps in these areas. They did not have time to be taken out the dumps for processing after the shutdown of the mines. There was no reclamation of polymetallic ore mining sites on Vaygach Island. Acidified rain and meltwater contribute to the gradual leaching of lead and other metals from ore dumps into surface and groundwater drains. For example, according to observations made by one of the authors of the present study in March 2024, snow on the island of Vaygach had slightly acidic properties, and the pH value of the thawed snow cover ranged from 4.38 to 4.80.

Another factor contributing to the ingress of a significant amount of metals into the Krasnaya River estuary may be an increase in the discharge of groundwater from the ore body. It is caused by the climate warming in the Arctic region in recent decades. There are forecasts about the continuation of this process into the 21st century [48]. At the ore mining site, the destruction of permafrost rocks with a high concentration of metals is enhanced by the penetration of heat and rain into their thickness through the destroyed mines.

The obtained results make it possible to propose algae and grasses that grow in the zone where the river and sea waters mix as an effective indicator of pollution of estuaries with heavy metals, namely, Fucus distichus as a perennial indicator, and Ulva prolifera as a seasonal indicator. This is also confirmed by a number of works by other authors [49,50,51,52].

5. Conclusions

Thus, it should be concluded that there is a certain negative impact of preserved (“abandoned”) polymetallic ore deposits in the Arctic region. It is manifested in the accumulation of toxic metals in the estuaries of rivers after such deposits drain into them. As studies on the island of Vaygach have shown, the most significant accumulation of metals is observed in filamentous algae at the site of localization of the frontal section between river and sea waters. For example, in the Krasnaya River catchment area where lead–zinc ores were mined 90 years ago, the Pb concentration in the algae reached 2.4 mg/kg, which exceeds the current Russian standard by 4.8 times. If the reclamation of the sites of the above-mentioned deposits is not carried out, then the negative effects on nature can persist for several decades. This should be taken into account in the economic development of the Arctic territories and, above all, the Arctic islands.