CC BY
0
Original papers
Materials for energy and environment, next-generation photovoltaics, and green technologies УДК 574:2.043 DOI: 10.17277/jamt.2023.02.pp.141-156
Heavy metal contents in the Tyumen city residential area soils
© Yana M. Chichiginaa, Gulnara N. Shigabaevaa^, Ekaterina A. Emelyanovaa, Evgeny V. Galunina, Artem S. Yakimovb, Alexei Yu. Isaeva, Maria R. Bekkera
a Tyumen State University, 6, Volodarskogo St., Tyumen, 625003, Russian Federation, b Institute of the Earth's Cryosphere, Tyumen Scientific Center of the Siberian Branch of the Russian Academy of Sciences,
86, Malygina St., Tyumen, 625026, Russian Federation
И g.n.shigabaeva@utmn.ru
Abstract: The present paper examines the state of pollution of soils in the city of Tyumen regarding heavy metals contained therein: nickel (Ni), cobalt (Co), manganese (Mn), copper (Cu), cadmium (Cd), lead (Pb) and chromium (Cr). Soil sampling was carried out in autumn 2021 within the city residential areas. The sampling points were chosen in the sites of increased anthropogenic load - near highways and industrial enterprises. In soil samples, the content of acid-soluble and mobile fractions of heavy metals and organic matter was determined, and the pH factor was also measured. The analysis showed that significant excesses, from 3.2 to 14.3 MPC level, were found on nickel in 11 soil samples, and all the soil samples belong to the zones of motor transport impact. In one sample, No. 29, which belongs to the impact zone of such large industrial enterprises as the Elektrostal Tyumen Metallurgical Plant (Ural Mining and Metallurgical Company-Steel, UMMC Steel) and the Motor Plant, the MPC for nickel was exceeded by 8.1 times. There were also excesses in the copper contents in 11 samples, from 1.5 to 4.9 MPC, and in both the zones of motor transport impact and the territories affected by the building materials enterprises, railway junction, and UMMC Steel. For lead, there was a two-times excess in two samples in the zone of motor transport impact, 4.4 times - in the impact zone of the Construction Machinery Plant, and 29.7 times - in the zone of impact of Velizhansky Highway. For cobalt, chromium and manganese, the MPC values for the acid-soluble fractions were not exceeded. For the mobile fractions, excesses were also observed for manganese. The highest excesses of the MPC level for nickel and copper were found in the Vostochny (Eastern) and Central districts of the city, in the areas affected by motor transport and the large enterprises.
Keywords: soil mantle; heavy metals; pH of saline extract of soils; soils; pH of aqueous extract of soils; degree of pollution; MPC; environmental monitoring.
For citation: Chichigina YaM, Shigabaeva GN, Emelyanova EA, Galunin EV, Yakimov AS, Isaev AYu, Bekker MR. Heavy metal contents in the Tyumen city residential area soils. Journal of Advanced Materials and Technologies. 2023;8(2):141-156. DOI: 10.17277/jamt.2023.02.pp.141-156
Содержание тяжелых металлов в почвах селитебной зоны г. Тюмени
© Я. М. Чичигинаа, Г. Н. Шигабаева"и, Е. А. Емельянова", Е. В. Галунина, А. С. ЯкимовЬ, А. Ю. Исаев", М. Р. Беккера
а Тюменский государственный университет, ул. Володарского, 6, Тюмень, 625003, Российская Федерация, Ь Институт криосферы Земли Тюменского научного центра СО РАН, ул. Малыгина, 86, Тюмень 625026, Российская Федерация
И g.n.shigabaeva@utmn.ru
Аннотация: Исследовано состояние загрязненности почв г. Тюмени на предмет содержания в них тяжелых металлов: никеля (№), кобальта (Со), марганца (Мп), меди (Си), кадмия (Cd), свинца (РЬ) и хрома (Сг). Отбор проб почв проводился осенью 2021 г. на селитебных участках в пределах города. Точки отбора выбирались в зонах повышенной антропогенной нагрузки - вблизи автомагистралей и промышленных предприятий. В пробах почв определено содержание кислоторастворимых и подвижных форм тяжелых металлов, и органического вещества, а также измерен водородный показатель (рН). Анализ показал, что значительные превышения выявлены по
никелю в 11 пробах почв от 3,2 до 14,3 ПДК, причем все пробы почв относятся к зонам влияния автотранспорта. В одной пробе № 29, которая относится к зоне влияния таких крупных промышленных предприятий, как Металлургический завод «Электросталь Тюмени» («УГМК-Сталь») и Моторный завод, превышено ПДК по никелю в 8,1 раза. По содержанию меди тоже есть превышения в 11 пробах, от 1,5 до 4,9 ПДК, причем в зонах влияния как автотранспорта, так и на территориях влияния предприятий строительных материалов, железнодорожной развязки, «УГМК Сталь». По свинцу есть превышения в двух пробах в два раза в зоне влияния автотранспорта, в 4,4 раза в зоне влияния Завода строительных машин, в 29,7 раз в зоне влияния автодорог Велижанского тракта. По кобальту, хрому и марганцу значения ПДК для кислоторастворимых форм не превышены. По подвижным формам превышения наблюдаются и по марганцу. Наибольшие превышения ПДК по никелю, меди выявлены в Восточном и Центральном районах города, в зонах влияния автотранспорта и крупных предприятий.
Ключевые слова: почвенный покров; тяжелые металлы; рН солевой вытяжки почв; рН водной вытяжки почв; степень загрязнения; ПДК; экологический мониторинг.
Для цитирования: Chichigina YaM, Shigabaeva GN, Emelyanova EA, Galunin EV, Yakimov AS, Isaev AYu, Bekker MR. Heavy metal contents in the Tyumen city residential area soils. Journal of Advanced Materials and Technologies. 2023;8(2):141-156. DOI: 10.17277/jamt.2023.02.pp.141-156
1. Introduction
Human activities to transform the soils of residential areas result in changes in the elemental composition of soils - heavy metals (HMs) enter the environment where they are able to accumulate in the soil, especially in the upper part of the soil. Besides, HMs are actively involved in geochemical cycles, through which they can penetrate into the atmosphere, hydrosphere, lithosphere and biosphere. Anthropogenic impacts on soils have a negative effect on their structure and characteristics: fertility and biomass production, dynamism and sustainability are reduced, which can lead to soil degradation. At the same time, soil is an indicator of the condition of the landscape and the degree of safety for human habitation. It should be noted that HMs have carcinogenic, toxic and mutagenic effects. The penetration of these pollutants into human and animal bodies leads to deterioration of the health of those ones, up to lethal outcome. In soils HMs are found as oxides, sulphides, and also as soluble salts such as chlorides, nitrates and sulphates. When acidic precipitation enters the soil, nitric acid dissolves the oxides and sulphides of the HMs. In the upper horizons of the soil profile, which contains the greatest amount of humus, metals bind with organic ligands, resulting in the formation of low-mobile complex compounds. Then, they accumulate in the upper horizons of the soil profile, but are not transported by downward water flow to the lower horizons. However, if the concentration of humus is low, the bulk of the HMs will be in a free state and transferred to the deeper horizons and layers under the influence of soil moisture [1].
In this regard, nowadays, the timely assessment of soil contamination with HMs appears to be an urgent task at present. In work [2], the authors
establish that more and more attention is given to soil pollution all over the world. This is due to the increasing number of oil and gas processing enterprises that leads to the prevalence of complex pollution from HMs and polycyclic aromatic hydrocarbons (PAHs). Soil co-pollution with the HMs and PAHs poses more serious threats to the environment and human health, such as increased toxicity to microbial activity and diversity, reduced bioavailability, and inhibition of plant growth. Possible ways of purifying soils from such pollutants are represented by electrokinetic remediation and leaching and the use of chelating agents.
Soil monitoring studies that are being conducted determine enrichment factor (EF), environmental risk calculation (ER), bioconcentration factor (BCF), transfer factor (TF), hazard index (HI), and carcinogenic risk (CR). Such studies provide insights into the controls of urbanization in relation to the combined severity of pollution and potential health risk [3].
The main source of HM contamination of soils is dust pollution. At the same time, the concentration of HMs is highest in the fractions having dust particle sizes of < 0.63 ^m. The penetration of such particles into the human body can cause a variety of diseases, including cancer [4].
The city of Tyumen is located in the southwest of the West Siberian Plain within the sub-taiga zone. Zonal soils are sod-podzolic and gray forest, black earth occurs closer to the forest-steppe. Soils are formed on covered loams, with the lower part of the profile predominantly of loamy granulometric composition, while the upper part of the profile is loamy-sandy. The soils are slightly alkaline and neutral.
The aim of the present work was to assess the pollution of soils of Tyumen city with the most common HMs (Ni, Co, Mn, Cu, Cd, Pb, Cr), organic matter (OM), as well as to determine the hydrogen index (pH).
2. Materials and Methods
In this study, soils contaminated with HMs in residential areas of Tyumen, as well as adjacent territories, were chosen as analysis objects.
At present, the following industries are being dynamically developing in the city: fuel industry (oil and gas processing), machine building, forestry, etc. There are large industrial facilities in and around Tyumen such as the Tyumen Battery Plant, the
Antipinsky Oil Refinery, UММС-Steel, and the Tyumen Plywood Plant. Moreover, Tyumen is a major transportation hub: The Trans-Siberian Railway, major highways and interchanges pass through its territory. Industrial and transport facilities are the sources of HM entering the environment and have a significant impact on its ecological situation. Soil sampling was conducted in urban and suburban areas. Samples were taken from the upper (0-10 cm) organo-mineral horizon that adsorbs a significant part of dust emissions due to its peculiar structure and large OM amount. Therefore, this soil layer was selected for the study. Characteristics of soil sampling points are presented in Table 1.
Table 1. Characteristics of Soil Samples
Sample No. Sampling point Possible impact
1 Pchyolka rural district Bypass road, Salair Highway
2 Mezhdurechenskaya Street Salair Highway
3 Tsimlyan Lake green area Battery Plant
4 Plekhanova village Bypass road, Plekhanovo Airport
5 Dudareva village Moscow Highway
6 Paderina village Moscow Highway, Chervishevsky Highway
7 City forest area Motor transport
8 Salair Highway, roadside Motor transport
9 Komunisticheskaya Street Motor transport
10 Mira Street Motor transport
11 Komarovo village Bypass road, Chervishevsky Highway
12 Chervishevsky Highway, roadside Motor transport
13 Salair Highway, roadside Motor transport
14 Kazarovo village Construction Machinery Plant
15 Druzhby Street, city park Motor transport
16 Kharkovskaya Street Motor transport
17 Shirotnaya Street Motor transport
18 Patrusheva village Motor transport
19 Yasny Horticultural Cooperative Velizhansky Highway
20 Velizhansky Highway, roadside Construction Machinery Plant, Motor transport
21 Malinovskogo Street Motor transport
22 Gilyovskaya grove Motor transport
23 Stantsionnaya Street UММС-Steel, Railroad junction, Motor transport
24 Fedyuninskogo Street, roadside Motor transport
25 Sadovoye Horticultural Cooperative Velizhansky Highway
26 Druzhby Street Bypas road, Plywood Plant
27 Tura River bank Motor transport
28 Antipino Starotobolsky Highway, Antipinsky Oil Refinery
29 Andreyevskoye Lake Motor plant, UММС-Steel, Motor transport
The pH of aqueous and saline extracts of the selected soils was determined through the method according to Russian Standard 26423-85. The OM content was assessed through gravimetry in accordance with Russian Standard 26213-91. The mass fraction of mobile and acid soluble forms of the metals (copper, lead, zinc, nickel, cadmium, cobalt, chrome, and manganese) in the soil samples was measured by atomic absorption method according to Guidance Document 52.18.289-90 and Guidance Document 52.18.191-89 respectively. The atomic-absorption method realized on a ContrAA700 spectrophotometer (AnalytikJena™,
Jena, Germany) using xenon lamp of continuous spectrum was used to quantify HM contents in acid and acetate-ammonium soil extracts.
3. Results and Discussion
3.1. Determination of pH and organic matter of soil samples
The results of determining the pH of aqueous and saline extracts of soils are shown in Figs. 1 and 2. From Fig. 1, it can be seen that the pH of the soil
I pH values of water extract ■ pH values of salt extract Fig. 1. pH values obtained for the aqueous and saline extracts
Central District Kalininskiy District Eastern District Leninskiy District Tyumensky District upH values of water extract pH values of salt extract Fig. 2. Average pH values obtained for the aqueous and saline extracts for different districts
solutions is predominantly alkaline. This fact can be explained by the contents of magnesium and calcium carbonates coming from construction and household wastes from industrial enterprises. Furthermore, transport can be an additional source of pollution source, especially, in areas with heavy traffic (e.g., near highways which give HMs in the form of dust particles [5]. High pH values are probably associated with an increase in the mobility of HM compounds that may accumulate in acidic soils due to the presence of humic acids [6].
The pH values of aqueous and saline extracts were found to lie in the ranges of 6.22-9.20 and
5.87-9.06, respectively and refer to neutral, low-alkaline and alkaline media.
The investigated soils belong to the objects with low resistance to acids and high sensitivity in relation to the HMs. Since the upper parts of the soil profiles have a sandy loam granulometric composition, the corresponding maximum permissible concentrations (MPCs) [Sanitary Rules and Regulations 1.2.3685-2] were taken when assessing the HM content.
The results on the OM determination are presented in Figs. 3 and 4 and Table 2.
Fig. 3. OM contents in the soil samples
12,00 n
10,00 -
8.00 -
6,00 -
4.00 -
2.00 -
0.00
Corg, %
Central District Kalininskiy District Eastern District Lenin ski y District Fig. 4. Average OM contents in the soil samples
Tyumensky District
Table 2. OM contents, pH of aqueous and saline extracts
Sample No. рН of aqueous extract рН of saline extract OM contents C^o^ %
1 8.05 7.89 5.26
2 7.87 7.56 1.65
3 8.20 8.02 2.52
4 6.22 5.87 5.69
5 6.68 6.36 10.46
6 7.92 7.65 3.58
7 7.54 7.31 7.34
8 8.70 8.60 4.79
9 7.54 7.31 1.39
10 7.38 7.13 8.73
11 7.41 7.24 6.85
12 8.99 8.89 3.34
13 7.99 7.76 11.25
14 7.71 7.37 4.64
15 8.37 8.09 9.76
16 8.28 8.10 8.85
17 7.82 7.58 10.29
18 7.02 6.70 9.92
19 8.62 8.48 6.57
20 9.20 9.06 5.59
21 7.77 7.53 10.19
22 6.80 6.51 14.24
23 7.66 7.45 12.66
24 7.51 7.30 11.18
25 8.29 8.08 6.65
26 8.00 7.81 5.15
27 8.40 8.16 10.86
28 7.52 7.37 7.19
29 8.51 8.32 2.90
The OM percentage in the upper soil horizon is 1.39-14.24 %. The soil sample with the highest OM amount was taken in the Gilyovskaya grove area. High OM contents were also observed in the soils sampled outside the Tyumen city limits and in the Leninsky administrative district of Tyumen city.
3.2. Determination of acid-soluble and mobile fraction of HM
The HM fraction extracted from the soil using ammonium acetate buffer (pH = 4.8) represents the mobile form of HM compounds. At this pH value, the most efficient uptake of trace elements by plants from the soil solution occurs. The mobile HM fraction is associated with its most transportable part. It determines the availability of mineral components to plants and soil toxicity. This fraction is found in the form, in which the HMs are integrated into geochemical cycles and food chains.
The results of determining the HM mobile fraction content of the of HM in the soil are presented in Table 3.
The HMs are extracted from the soil solution using ammonium acetate buffer through ion exchange and complexation reactions. The predominance of one or the other process depends on the nature of the metal to be extracted. For instance, for cobalt and zinc, the extraction is caused to a greater extent by the complexation reaction, whereas for chromium and cadmium, it is caused by the ion exchange reaction [7].
The gross HM content in the soils is determined when the soil samples are exposed to strong acids (5n-HNO3). The value of this indicator makes it possible to judge on the total contamination of soils with the HMs, however, it should be noted that this indicator does not provide information on the element availability of elements [8]. High values of the gross HM content indicate a potential environmentally unfavourable situation of the territory; that is, if the water and plants are not polluted at the moment, the ecological situation may change for the worse if external factors change.
Table 3. Contents of the HM mobile fractions, mg-kg 1
Sample No. Ni eo Mn Cu Cd Pb Cr
1 19.3±5.8 - 76±23 0.53±0.16 - - 5.50±1.70
2 - - 35±10 0.87±0.26 - 5.90±1.80 1.73±0.50
3 - - 41±12 0.68±0.20 - - 1.70±0.52
4 1.40±0.43 - 54±16 0.45±0.14 - 0.33±0.10 2.50±0.76
5 - - 70±21 0.39±0.12 - - 2.01±0.60
6 2.40±0.71 - 52±16 1.02±0.30 - 0.47±0.14 2.42±0.73
Continue Table 3
Sample No. Ni Co Mn Cu Cd Pb Cr
7 - - 301±90 0.41±0.12 - - 2.12±0.63
8 21.1±6.2 - 89±27 1.83±0.55 - 42±13 4.30±1.30
9 - - 43±13 0.97±0.29 - 1.94±0.56 2.44±0.72
10 8.9±2.7 - 171±51 0.92±0.28 - 1.91±0.58 2.81±0.85
11 - - 77±23 0.37±0.11 - - 1.50±0.46
12 31.2±9.4 0.34±0.10 88±26 3.01±0.89 - 6.8±2,0 4.00±1.20
13 5.8±1.8 0.15±0.04 103±31 0.67±0.20 - 20.0±6.1 2.02±0.60
14 1.81±0.55 - 65.±20 0.60±0.18 - - 4.90±1.50
15 0.140±0.043 - 149±45 0.44±0.13 - - 0.91±0.27
16 - - 143±43 4.60±1.40 - - 1.21±0.37
17 - - 148±44 0.52±0.16 - - 1.41±0.42
18 - - 174±52 1.40±0.41 - 9.7±2.9 0.84±0.25
19 30.1±9.1 - 84±25 1.82±0.55 - 18.0±5.4 3.23±0.95
20 27.2±8.2 - 101±30 5.60±1.70 - 80±24 3.90±1.20
21 - - 90±27 0.65±0.20 - 2.90±0.88 0.87±0.26
22 - - 228±68 0.80±0.24 - 3.31±0.99 1.13±0.34
23 - - 136±41 0.50±0.15 - 7.3±2.1 1.13±0.33
24 3.30±0.99 - 147±44 0.68±0.20 - - 2.51±0.74
25 19.0±5.6 1.10±0.19 287±86 9.20±2.80 2.60±0.77 2076±622 8.20±2.50
26 - - 72±22 1.01±0.30 - 0.36±0.11 0.96±0.29
27 0.62±0.19 - 332±100 1.01±0.30 - 2.08±0.62 1.41±0.42
28 22.3±6.7 0.62±0.19 95±28 2.44±0.73 - 2.63±0.77 4.20±1.30
29 - - 92±27 1.12±0.33 - - 1.60±0.49
MPC 4 5 140 3 6 6
Table 4. Contents of the HM acid-soluble fractions, mg-kg- 1
Sample No. Ni Co Mn Cu Cd Pb Cr
1 160±48 8.8±2.6 267±80 15.3±4.4 - 0.88±0.26 71±21
2 4.8±1.4 3.01±0.91 165±50 71±21 - 16.00±4.90 4.1±1.1
3 28.0±8.4 9.4±2.8 487±146 62±19 - 3.31±0.10 21.1±6.2
4 26.1±7.9 13.1±3.8 604±181 67±20 - 0.96±0.29 21.2±6.2
5 36±11 14.0±4.2 549±165 47±14 - 0.84±0.25 21.4±6.4
6 36±11 3.9±1.2 165±49 34±10 - 14.00±4.10 18.0±5.5
7 3.5±1.1 3.4±1.0 366±110 163±49 - - 3.3±1.0
8 189±57 11.1±3.2 362±109 39±12 - 61±19 65±20
9 14.0±4.1 6.1±1.8 267±80 50±15 - - 9.1±2.6
10 133±40 12.1±3.6 407±122 18.1±5.3 - 3.6±1.1 50±15
11 21.1±6.3 8.9±2.7 401±120 25.3±7.6 - - 15±4.4
12 238±72 14.1±4.3 273±82 26.2±7.9 - - 82±24
13 114±34 8.5±2.5 264±79 114±34 - 22.1±6.6 34±10
Continue Table 4
Sample No. Ni Co Mn Cu Cd Pb Cr
14 42±13 7.2±2.2 199±60 38±11 - - 102±31
15 44±13 3.30±0.99 407±122 43±13 - - 17.4±5.1
16 67±20 12.0±3.5 449±135 20.0±5.9 - - 34±10
17 63±19 7.5±2.3 398±119 51±15 - - 31±9,2
18 33±9.8 6.1±1.8 360±108 158±47 - - 16.4±4.8
19 286±86 17.2±5.1 266±80 15.2±4.4 - 32.3±9.7 71±21
20 228±68 12.0±3.7 298±89 62±18 - 140±42 65±19
21 42±13 7.8±2.3 579±174 10.4±3.0 - 8.2±2.5 26.2±7.9
22 35±10 8.6±2.6 812±243 30.2±8.9 - 16.0±4.9 16.1±4.9
23 37±11 5.6±1.7 325±97 61±18 - 11.0±3.2 12.1±3.7
24 72±22 3.6±1.1 319±96 37±11 - - 24±7.3
25 199±60 11.0±3.4 798±239 13.1±3.8 4.8±1.4 951±285 87±26
26 33±10 6.6±2.0 496±149 33.0±9.9 - 3.4±1.0 16.0±4.7
27 74±22 7.1±2.1 688±207 27.2±8.1 - 10.0±3.1 22.3±6.7
28 23.4±7.0 7.7±2.3 510±153 79±24 - 18.4±5.3 17.1±5.0
29 161±48 9.1±2.7 218±65 49±15 - 15.3±4.5 64±19
MPC 20 20 1500 33 0.5 32 100
The results on the content of HM acid-soluble forms in the soil are presented in Table 4.
The HM content in sample No. 25 significantly exceeded the MPC values; that sample was taken from the territory of Sadovoye Horticultural Cooperative, where agrarian works have been carried out for several years. A large HM amount could come into the soil from phosphate fertilizers, in which the HM contents can reach 220 mg-kg-1 [9]. On this basis, the authors of this study assumed that a large fertilizer amount was entering the soil, or that the site was used as a landfill. Therefore, in further consideration of the data obtained, the values for sample No. 25 were excluded from the total set.
Nickel. The MPC of nickel in the soils of residential areas is 20 mg-kg-1 for acid soluble fractions and 4 mg-kg-1 for its mobile fractions. The most common are Ni2+ compounds. Ni3+ exists in an alkaline environment as well as under harsh oxidizing conditions, but such conditions are rare in the natural environment [10, 11]. Nickel is a moderate complexing agent capable of forming predominantly fulvate complexes with organic or inorganic ligands. Besides, it can also be found in soils as carbonate or hydrocarbonate complexes, with the ratio of one or the other complex form depending on the acidity of the medium [12]. Compounds of this element can be adsorbed by fine-grained clay
particles as well as by iron, manganese and aluminum hydroxides [13].
Nickel sources may include a variety of industrial emissions, vehicle fuel emissions, and parts of rubber tyres. At different sampling points, the levels of the nickel contents exceeding the MPC were observed, suggesting that the contamination with this metal is not local but extensive, covering the whole area (see Figs. 5, 6).
This contamination may be caused by roads connecting different parts of the city. The high content of the nickel acid-soluble fractions in many samples exceeded the MPC by a factor of 2 to 14, thereby indicating its accumulation in the soils of these districts. The excess levels of the nickel contents in the samples taken near the roadsides (bypass road, as well as the highways: Salair, Chervishevsky, Moscow and Velizhansky) allow concluding about the transport impact.
Cobalt. The MPC level for its acid-soluble fractions is 20 mg-kg-1, whereas for its mobile fractions of cobalt in the case of the soils of residential areas, it is 5 mg-kg-1. In most cases the cobalt contents in soils depend on the parent rock composition. Considerable quantities of cobalt are identified in soils formed from basic rocks and clay sediments. It should be taken into account that the pattern of the cobalt distribution and behavior in soils is much affected by humus contents in the soil horizon.
Ni, nig/kg
400
350 300 250 200 150 100 50 0
yj
-h
1 | 2 | 7 | 8 | 13 | 14 | 15 | 20 Central District
3 | 4 | 9 | 10
Kalininskiy District
M
11 I 12 I 17 I 29 Eastern District
M-i-U
16 | 19 | 21 | 22 | 23 | 24 | 26 \ 27 | 28 Lenin ski y District
iM
5 | 6 | 18
Tyumensky District
Ni, mg/kg--MPC
Fig. 5. Contents of the nickel acid-soluble fractions in the soil samples
Ni, mg/kg
180 -i
160 -140 -120 -100 -80 -60 -40 -20 -0--
■
Central District Kalininskiy District Eastern District Lenin skiy District Tyumensky Distiict
Ni, mg/kg--MPC
Fig. 6. Average contents of the nickel acid-soluble fractions in the soil samples
Cobalt takes different forms depending on pH of the environment and is found as Co2+ and Co3+, or as the complex anion Co(OH)3-, i.e. in the mobile form.
The results on the cobalt contents show that none of the Tyumen districts exceeded the MPC level established for both acid-soluble and mobile fractions of this element (Figs. 7, 8).
Manganese. The manganese MPC level is as follows: for its mobile fractions, it is 140 mg-kg-1, whereas for its acid-soluble fractions, it is 1500 mg-kg-1. This metal is found in soils more often than other elements. The main place of its accumulation
is the top soil layer, since it actively interacts there
with the OM. In nature, manganese occurs mainly as
Mn , Mn , Mn +, or as minerals. Manganese 2+
(as Mn ) can replace divalent cations of some 2+ 2+
elements (Fe , Mg ) in silicates and oxides, thereby forming ferromanganese nodules, so it is the most common one in the environment.
Slightly excessive levels of manganese MPC for the mobile fractions were observed in samples No. 17, 16 and 26, and in samples Nos. 7,10, 18, 22, 25 and 27 (Table 3), a significant MPC excess was fixed.
Co, mg/kg
25
20
15
10
ii
ii
1 2 7 8 13 14 15 20 3 4 9 10 11 12 17 29 16 19 21 22 23 24 26 27 28 5 6 18
Central District Kalininskiy District Eastern District Leninskiy District Tyumensky District
Co, mg/kg--MFC'
Fig. 7. Contents of the cobalt acid-soluble fractions in the soil samples
Co, mg/kg
25
20
15
10
Central District
Kalininskiy District
Eastern District
Leniuskiy District Tyumeusky District
Co, mg/kg — — MPC Fig. 8. Average contents of the cobalt acid-soluble fractions in the soil samples
A large OM amount is available in the inspected territories, since the above-mentioned samples were taken in landscaped urban areas (city forest and parks, riverbank, roadside forest belt, and green area near houses). The OM enters the soil with fallen leaves and grass. The disruption of the system of fallen leaves removal at urban sites results in large OM quantities [14]. Manganese accumulates in the upper soil horizons and is not leached to the lower horizons, since it forms insoluble complex compounds with the OM. The activities of ferrous and non-ferrous metallurgy, metal processing and machine building industries result in manganese entering the soil horizons. The soil samples from the area of UMMC-Steel (samples No. 22, 24, 27)
possess have high content of mobile fractions, which may indicate its recent entry.
The contents of the manganese acid-soluble fractions in all samples lied within normal limits,
indicating the leaching of this element from the soils
2+
in the form of mobile Mn (Figs. 9, 10).
Copper. The MPC level for the copper acid-soluble fractions is 33 mg-kg-1, and for its mobile fractions in the soils of residential areas is 3 mg-kg-1.
Copper is a highly toxic element and is most
2+
commonly found as Cu compounds. At the same time, it is one of the least mobile HMs, because in nature, due to good complexing properties, it forms complexes mainly with organic ligands.
Mn, m g/kg
1600 -i
1400 -1200 -1000 -800 -600 -400 -200 -
0
1 | 2 | 7 | 8 |13 | 14 | 15| 20 3 | 4 | 9 | 10 11 | 12 | 17 \l9
Central District Kalininskiy Eastern District
District
^^m Mil, mg/kg — —
16 I 19 I 21 I 22 I 23 I 24 | 26 | 27 | 28 Lenin ski y District
MPC
Fig. 9. Contents of the manganese acid-soluble fractions in the soil samples
5 | 6 118
Tyumensky District
Md. nig/kg
1600
1400 -1200 -1000 -800 -600 -400 -200 -
0
* É É
É
Central District Kalininskiy District Eastern District Leninskiy District Tyumensky District
mg/kg — — MPC
Fig. 10. Average contents of the manganese acid-soluble fractions in the soil samples
Copper becomes most toxic at pH values of 5.5 to 6.5 as it is dissolved as divalent copper ions. In more acidic soils, copper is less mobile and, therefore, non-toxic. At pH more than 9.0, complexes with inorganic ligands can be formed. Also, adsorption on suspended clay particles decreases its mobility. The excess of the content of the copper mobile fractions was found in samples No. 20 and 26, although these values do not exceed the MPC more than twice (Table 3). The accumulation of copper in soils in the form of complex compounds with fulvic acids is evidenced by exceeding of the MPC on average from 2 to 5 times for the copper acid-soluble fractions (Figs. 11, 12).
Cadmium. The MPC level for the cadmium acid-soluble fractions is 0.5 mg-kg-1, and no standard value has been established for its mobile fractions.
Cadmium is mainly accumulated in the form of complexes with humic acids. It is a rarely dispersed element and is considered to be one of the most toxic metals, since its rates exceed permissible levels even at the minimum soil contamination value. The background cadmium content in soils is mainly determined by the composition of its parent rock. Cadmium is most mobile in soil solution media at pH 4.5-5.5. In alkaline conditions, it is low-mobile, therefore, its mobility values correlate with the acidity of the soil solution medium.
eu, ni g/kg 250 n
200 -
150 -
100
50 -
rlMtijiîittr.-.-tithljl
1 I 2 | 7 | 8 | 13 | 14 | 15 | 20 Central District
3 | 4 | 9 |10
Kalininskiy District
11 | 12 | 17 | 29 Eastern District
16 | 19 | 21 |22 | 23 | 24 | 26 \27 | 28 Leninskiy District
5 | 6 | 18
Tyumensky District
mg/kg--MPC
Fig. 11. Copper contents in the soil samples
Cu, mg/kg
120
100 -
80 -
60
40 -
20
_L
Central District
Kalininskiy District
Eastern District
Leninskiy District Tyumensky District
i Cn, mg/kg
MPC
Fig. 12. Average copper contents in the soil samples
When considering the data of the analyzed samples of Tyumen city, no excess of the MPC for this element was noted (see Tables 3, 4).
Lead. The MPC level for the lead mobile fractions in the case of soils from residential areas is 6 mg-kg-1, for its acid-soluble fractions, it is 32 mg-kg-1. Lead compounds accumulate in soils as a result of sorption on oxides and hydroxides of manganese and iron. Moreover, lead forms part of easily degradable minerals - PbO, PbCO3, and PbSO4. Degradability makes these forms of lead in soils the most dangerous. At the same time, the phosphate mineral [Pb5(PO4)3Cl] is the least toxic as it has low solubility and stability in a wide pH range. The mobility and bioavailability of lead without its
removal from the medium can be achieved by applying phosphate to contaminated soils. This reaction can be represented as follows:
Ca5(PO4)OH + 5Pb2+ ^ Pb5(PO4)OH + 5Ca
A significant excess of the MPC level for lead both in the mobile and the acid-soluble form was observed in samples No. 8 and 20 taken at roadsides (Tables 3, 4). For these soils, 7- and 13-fold excesses of the MPC level for its mobile fractions, and 2- and 4-fold excesses of the MPC for the acid-soluble fractions were observed, respectively (Figs. 13, 14).
Possible sources of lead pollution are wastes from metallurgical plants, landfills of used electric batteries, paints, and metal alloys. In addition, lead
2+
Pb, mg/kg
200 -|
ISO -160 -140 -120 -100 -
0
1 2 8 13 20 29 19 21 22 23 26 27 28 5 6
HPb, rag/kg--MPC
Fig. 13. Contents of the lead acid-soluble fractions in the soil samples
Pb, mg/kg
70 -i
60 -50 -40 -
Central District
Pb, mg/kg--MPC
Fig. 14. Average contents of the lead acid-soluble fractions in the soil samples
fUlvic acids. It should be noted that these forms are actively adsorbed by clays, whereas the CrO4 chromate anion is adsorbed only in more acidic media.
The presence of chromium in one form or the other also determines its toxicological properties. The most dangerous are the Cr+6 compounds, which have toxic, carcinogenic and mutagenic effects. At the same time, Cr+3 compounds in acidic media are inert, and at pH 5.5 become almost insoluble, so they do not harmfully affect the organisms.
The main areas of chromium application are metallurgical and chemical industries due to high corrosion resistance and strength of this element [17].
Among the investigated samples, only sample No. 14 exceeded the MPC established for chromium. However, the exceeding of the limits for the contents of the acid-soluble fractions is insignificant.
may enter soils from exhaust gases of vehicles running on petrol with lead additive. Its excessive concentrations were observed in the Central district, which can be explained by the increased traffic load in this part of the city.
Chromium. The MPC level established for its mobile fractions in case of soils of residential areas is 6 mg-kg-1, and for the acid-soluble fractions, it is 100 mg-kg-1. Chromium exists in several forms, the most stable of which are compounds with oxidation degrees of +6 and +3. The form, in which chromium is found in soils, depends not only on the acidity of the medium [15], but also on its redox potential [16].
Thus, +6 oxidation degree chromium possesses
low complexing ability, and is available in soils as
HCrO4- and CrO42-. +3 degree chromium, in its turn,
has high complexing properties and, as a result, it is
+ 2+ present in soil solution as [Cr(OH)2] and [Cr(OH)]
(at pH 7.5-8.5) as well as complexes with humus and
Cr, nig/kg
140
120 100 80 60 40 20 0
a B
1 | 2 | 7 | 8 | 13 | 14 | 15 | 20 Central District
11,11
iiliiliil
3 4 9 10 11 12 17 29 16 19 21 22 23 24 26 27 28 5 6 18
Kalininskiy Distiict Eastern Distiict Lenin ski y Distiict Tyumensky Distiict
Cr, mg/kg--MPC
Fig. 15. Contents of the chromium acid-soluble fractions in the soil samples
Cr, mg/kg
120 -
100 -
80 -
60 -
40 -
20
i
I .
Cental Distiict Kaliiiiiiskiy Distiict Eastern District Leiiiiiskiy Distiict Tyumensky Distiict
Cr, mg/kg--MPC
Fig. 16. Average contents of the chromium acid-soluble fractions in the soil samples
3.3. Correlation analysis
According to the Goldschmidt classification, all the elements in nature belong to one of the five groups: atmophilic, chalcophilic, lithophilic, siderophilic, as well as rare elements and elements not found in nature [18]. In this paper, a correlation analysis was carried out between the contents of the different element pairs. This type of analysis can reveal the absence or presence of correlation between elements belonging to the same group according to the geochemical classification of Goldschmidt, as well as indicate the possible causes of the HM accumulation.
Within the framework of this classification, matrices of pair wise correlations for the HM and OM contents and pH were constructed using the Microsoft Excel software. Indicators with a correlation coefficient of 0.5 were considered as correlated. The results of the analysis are presented in Table 5.
The highest correlations were found between the pairs of the following metals: Co - Ni, Cr; Pb - Cr; Cr - Ni, Co, Pb. The presence of correlations between nickel and cobalt contents is quite understandable, as they belong to siderophilic group of elements. The correlation between lead and chromium contents, different in nature, indicates the
Table 5. Matrices of pairwise correlations of the HM acid-soluble fractions in the soils
Ni, mg-kg 1 Co, mg-kg 1 Mn, mg-kg 1 Cu, mg-kg 1 Pb, mg-kg 1 Cr, mg-kg-1 pH Corg, %
Ni, mg-kg-1 1.00 0.67 -0.16 -0.34 0.36 0.80 0.65 -0.15
Co, mg-kg-1 0.67 1.00 0.22 -0.38 0.17 0.54 0.15 -0.06
Mn, mg-kg-1 -0.16 0.22 1.00 -0.21 0.39 -0.17 -0.30 0.48
Cu, mg-kg-1 -0.34 -0.38 -0.21 1.00 -0.26 -0.41 -0.28 0.08
Pb, mg-kg-1 0.36 0.17 0.39 -0.26 1.00 0.54 0.21 -0.06
Cr, mg-kg-1 0.80 0.54 -0.17 -0.41 0.54 1.00 0.52 -0.28
pH 0.65 0.15 -0.30 -0.28 0.21 0.52 1.00 -0.35
Corg, % -0.15 -0.06 0.48 0.08 -0.06 -0.28 -0.35 1.00
anthropogenic nature of their entry into the environment.
A correlation between the chemical element content in the soil and the pH of the aqueous extract for Cu, Cr, Ni was also been detected. This information can be interpreted as a confirmation of the effect of metal accumulation effect during the soil alkalinization, since in the samples studied, there was a shift to the alkaline pH region. The observed correlation between the soil OM content and the manganese concentration is related to the formation of strong complexes with the soil organic component.
4. Conclusion
Thus, in the present work, the pH values of saline and aqueous soil extracts were determined to be 5.87 to 9.06 and 6.22 to 9.20, respectively. A comparison of the obtained results on the HM content in the soils with Sanitary Rules and Regulations normative values showed that the contents of both mobile and acid-soluble fractions exceed the MPC values for copper, lead, nickel and manganese. The concentrations of cobalt, cadmium and chromium are not exceeded. Based on the correlation analysis of these results, it can be concluded that there is a significant anthropogenic load on the soils of Tyumen city, especially for the Vostochny (Eastern) and Central districts, where the main transport routes and industrial enterprises (UMMC-Steel, Construction Machinery Plant) are located.
5. Funding
No external funding was received for this research.
6. Acknowledgement
The authors would like to express their deep gratitude to the Core Facilities Center "Rational
Nature Management and Physical Chemical Research" of the Tyumen State University, Russia, and its head, Doctor of Chemical Sciences, Professor Nikolay Tretyakov, for the equipment provided for measurements and result processing.
7. Conflict of interests
The authors declare no conflict of interest.
References
1. Rusanov AM, Teslya AV, Prichogai NI, Turlibekova DM. The content of total and mobile forms of heavy metals in soils of Orsk city. Vestnik Orenburgskogo gosudarstvennogo universiteta. 2012;4:57-89. (In Russ.)
2. Zhang X, Zhang X, Wang S, Zhao S. Improved remediation of co-contaminated soils by heavy metals and PAHs with biosurfactant-enhanced soil washing. Scientific Reports. 2022;12(1):3801. D01:10.1038/s41598-022-07577-7
3. Rezapour S, Moghaddam S, Nouir A, Aqdam K. Urbanization influences the distribution, enrichment, and ecological health risk of heavy metals in croplands. Scientific Reports. 2022;12(1):3868. D0I:10.1038/s41598-022-07789-x
4. Al-Swadi, Usman A, Al-Farraj, Al-Wabel M, Ahmad M, Al-Faraj A. Sources, toxicity potential, and human health risk assessment of heavy metals-laden soil and dust of urban and suburban areas as affected by industrial and mining activities. Scientific Reports. 2022;12(1):3868. D0I:10.1038/s41598-022-12345-8
5. Jiang H, Cai L, Wen H, Luo J. Characterizing pollution and source identification of heavy metals in soils using geochemical baseline and PMF approach. Scientific Reports. 2020;10(1):6460. D0I:10.1038/s41598-020-63604-5
6. Kogan RM, Kalmanova VB. Soil acidity as an indicator of the ecological state of the urban area (on the territory of the city of Birobidzhan). Regional problems. 2008;10:83-86. (In Russ.)
7. Ladonin DV. Forms of compounds of heavy metals in polluted soils. Moscow: Moscow University Press; 2019. 312 p. (In Russ.)
8. Kovrigo VP, Kaurichev IS, Burlakova LM. Soil science with the basics of geology. Moscow: Kolos; 2000. 416 p. (In Russ.)
9. Vodyanitskii YuN. Metals and metalloids in soils. Moscow: VV Dokuchaev Soil Science Institute; 2008. 164 p. (In Russ.)
10. Moore JM. Inorganic contaminants of surface water: research and monitoring priorities. New York: Springer-Verlag; 1991. 366 p.
11. Gao W, He W, Zhang J, Chen Y, Zhang Z, Yang Y, He Z. Effects of biochar-based materials on nickel adsorption and bioavailability in soil. Scientific Reports. 2023;13(1):5880. D0I:10.1038/s41598-023-32502-x
12. Rocha JC, Desene J, Dossantos A, Toscano IA, Zara LF. Aquatic humus from an unpolluted Brazilian dark brown stream: general characterization and size fractionation of bound heavy metals. Journal of Environmental Monitoring. 2000;2(1):39-44. DOI: 10.1039/a907671i
13. Kuznetsov IP. Heavy metals in the soils of the Ryazan region. Himiya v sel'skom hozyajstve. 1995;5:22-25. (In Russ.)
14. Tessier A, Campbell PGC, Bisson M. Sequential extraction procedure for the speciation of particulate trace metals. Analytical Chemistry. 1979;51(7):844-851. D01:10.1021/ac50043a017
15. Plestemjak E, Kraigher B, Leskovec S, Mulec I, Markovic S, Scancar J, Milacic R. Reduction of hexavalent chromium using bacterial isolates and a microbial community enriched from tannery effluent. Scientific Reports. 2022;12(1):20197. D0I:10.1038/s41598-022-24797-z
16. Medvedev IF, Derevyagin SS, Gubarev DI. Distribution of heavy metals in chernozems of the main azonal landscapes and agrolandscape elements in the Volga region. Plodorodie. 2009;3:52-53.(In Russ.)
17. Klimov ES, Davydova OA, Zavaltseva OA, Borisova VV. To the question of the distribution of heavy metals in natural environments. FundamentaVnye issledovaniya. 2004;2:137-138. (In Russ.)
18. Orlov DS, Sadovnikova LK, Sukhanova NI. Soil chemistry. Moscow: Vysshaya shkola; 2005. 558 p. (In Russ.)
Information about the authors / Информация об авторах
Yana M. Chichigina, Assistant, University of Tyumen (UTMN), Tyumen, Russian Federation; ORCID 00090008-7909-0032; e-mail: y.m.chichigina@utmn.ru
Gulnara N. Shigabaeva, Cand. Sc. (Engineering), Associate Professor, Head of the Department of Organic and Ecological Chemistry, UTMN, Tyumen, Russian Federation; ORCID 0000-0003-2116-1017; e-mail: g.n.shigabaeva@utmn.ru
Ekaterina A. Emelyanova, Master's Degree Student, UTMN, Tyumen, Russian Federation; e-mail: stud0000040057@study.utmn.ru Evgeny V. Galunin, Ph.D., Associate Professor, UTMN, Tyumen, Russian Federation; ORCID 00000002-8219-0148; e-mail: e.v.galunin@utmn.ru Artem S. Yakimov, Leading Researcher, Earth Cryosphere Institute, Tyumen Scientific Center, Siberian Branch, Russian Academy of Sciences, Tyumen, Russian Federation; ORCID 0000-0002-13038492; e-mail: Yakimov_Artem@mail.ru
Alexei Yu. Isaev, Senior Lecturer, UTMN, Tyumen, Russian Federation; ORCID 0000-0002-2163-9968; e-mail: a.y.isaev@utmn.ru
Maria R. Bekker, Student, UTMN, Tyumen, Russian Federation; e-mail: stud0000228750@study.utmn.ru
Чичигина Яна Михайловна, ассистент, Тюменский государственный университет (ТюмГУ), Тюмень, Российская Федерация; ORCID 0009-0008-79090032; e-mail: y.m.chichigina@utmn.ru Шигабаева Гульнара Нургаллаевна, кандидат технических наук, доцент, заведующий кафедрой органической и экологической химии, ТюмГУ, Тюмень, Российская Федерация; ORCID 0000-00032116-1017; e-mail: g.n.shigabaeva@utmn.ru Емельянова Екатерина Александровна, магистрант, ТюмГУ, Тюмень, Российская Федерация; e-mail: stud0000040057@study.utmn.ru Галунин Евгений Валерьевич, Ph.D., доцент, ТюмГУ, Тюмень, Российская Федерация; ORCID 0000-0002-8219-0148; e-mail: e.v.galunin@utmn.ru Якимов Артём Сергеевич, ведущий научный сотрудник, Институт криосферы Земли Тюменского научного центра Сибирского отделения Российской академии наук, Тюмень, Российская Федерация; ORCID 0000-0002-1303-8492; e-mail: Yakimov_ Artem@mail.ru
Исаев Алексей Юрьевич, старший преподаватель, ТюмГУ, Тюмень, Российская Федерация; ORCID 0000-0002-2163-9968; e-mail: a.y.isaev@utmn.ru Беккер Мария Романовна, студент, ТюмГУ, Тюмень, Российская Федерация; e-mail: stud0000228750@study.utmn.ru
Received 04 April 2023; Accepted 03 May 2023; Published 06 July 2023
Copyright: © Chichigina YaM, Shigabaeva GN, Emelyanova EA, Galunin EV, Yakimov AS, Isaev AYu, Bekker MR, 2023. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
