Quality Problems of Surface Water and Groundwater at the Health Resorts in the Regions of Caucasian Mineral Waters and Ways to Their Solution I

ISSN 0097-8078, Water Resources, 2019, Vol. 46, No. 2, pp. 214–225. © Pleiades Publishing, Ltd., 2019. Russian Text © I.S. Pomelyaiko, A.V. Malkov, 2019, published in Vodnye Resursy, 2019, Vol. 46, No. 2.

HYDROCHEMISTRY, HYDROBIOLOGY: ENVIRONMENTAL ASPECTS

Quality Problems of Surface Water and Groundwater at the Health Resorts in the Regions of Caucasian Mineral Waters and Ways to Their Solution I. S. Pomelyaikoa, * and A. V. Malkova aNorth-Caucasian Federal University, Pyatigorsk, 357700 Russia *e-mail: [email protected] Received July 7, 2017; revised April 26, 2018

Abstract—The results of long-term environmental monitoring of small rivers in a health resort region are given. The characteristic of surface water and groundwater of health resorts of Caucasian Mineral Waters is discussed; the extent and character of their pollution are assessed. The causes of water pollution by heavy metal compounds, oil products, and nitrogen-containing compounds are analyzed. Data on the mineral water from several production wells failing to meet the requirements of GOST R 54316-2011 are given. The main factors that have an effect on water resources pollution in the region are identified. The hydrogeody- namic and hydrogeochemical operation regimes of the Kislovodsk Deposit are analyzed, and recommenda- tions for improving the quality of the main spring of the Narzan deposit are given.

Keywords: health resorts of Caucasian Mineral Waters, rivers, mineral waters, pollution, excess of MAC, drainage structures DOI: 10.1134/S009780781902012X

INTRODUCTION The objective of this study was to determine the qualitative composition of surface water and ground- The health resorts of Caucasian Mineral Waters water at CMW health resorts, to assess the degree and (CMW)—Essentuki, Zheleznovodsk, Kislovodsk, and character of their pollution, and to identify the causes Pyatigorsk—have formed and exist now owing to the of formation of higher concentrations of pollutants in hydromineral base, tambukanskie peloids, and cli- water bodies. mate. The regional infrastructure and economic stability are directly related with the amount and quality of mineral waters used for drinking, balneotherapy, THE MOST UNFAVORABLE MINERAL and bottling. The geomorphological, climatic, tec- SOURCES IN CMW REGION tonic, geological, and hydrogeological conditions of Zheleznovodsk [4]. In the early 1980s, mineral the region represent a very complex system, which water supply from the Batalinskoe deposit was ceased contributes to the input of pollutants into transporting because of its pollution by toxic chemicals and bacte- media and their accumulation in soil. The state of sur- ria. In the II zone of sanitary protection, subsoil water face waters and groundwater at CMW health resorts, contains extremely high concentrations of manganese especially, in their upper hydrodynamic zone, is very up to 68 times the MAC, lithium up to 22.8 MAC, and unfavorable [3–6, 16]. Because of the high level of boron up to 3.9 MAC. subsoil water pollution, the artesian mineral water, Pyatigorsk [6]. Mineral-water quality in the wells underlying them, is polluted by bacteria and contains Akademicheskaya 2, Teplosernaya 1 and 3, Radiosh- higher concentrations of heavy metals, nitrogen com- tol’nya 2, Narodnyi, etc. is unstable in terms of micro- pounds, oil products, phosphates, etc. [3–6, 11]. The biological characteristics and, therefore, cannot be majority of wells and mineral-water pipelines have used for drinking. Subsoil water was found to contain exceeded their performance life, as they had been higher concentration of oil products (up to brought into operation as long ago as XIX and the early 17.8 MAC), Mn (up to 15), Ba (up to 18), As (up to 3), and middle XX century [25], because of which, ammonium (up to 20), and B (up to 5 MAC). backup wells are to be drilled and a capital repair is to Essentuki [3]. Because of bacterial pollution and be made at the mineral water intake and above-ground the loss of condition, water from the Quaternary aqui- structures. fer Essentuki-20 and Gaazo-Ponomarevskii are not

214 QUALITY PROBLEMS OF SURFACE WATER AND GROUNDWATER 215 used for drinking. Groundwater was found to contain spheric pollution (PAP), the territory of CMW shows ammonium in concentration of up to 20 MAC; higher potential of atmospheric pollution (zone II, nitrates, up to 10; Ba, up to 28; Sr, up to 10; B, up to 8; class II b1) [1]. To increase the accuracy, the meteoro- and phenols, up to 70 MAC. logical potential of atmospheric self-purification Kislovodsk [5, 15]. The microbiological state of (MPA) was calculated in [21] for each resort; it is water from “Narzan” spring is steadily declining. In defined as the ratio of the recurrence of the conditions 1990s, the share of substandard samples was 65–90% favorable for the accumulation of pollutants to the of their total annual number; now, practically 100% of recurrence of conditions favorable for their removal samples are substandard. Groundwater in the I zone of from the atmosphere [27]. At MPA < 1 in some sanitary protection contains high concentrations of Sr period, the conditions are favorable for dispersion of (up to 13 MAC), Fe (up to 49), Mn (up to 15), As (up pollutants in the atmosphere, while at MPA > 1, the to 2), Ba (up to 5), and Al (up to 4 MAC) [16, 20]. dominating processes facilitate their accumulation. Water from the well 5/0-bis, subject to GOST R The self-purification ability of the atmosphere (dis- 54316-2011, cannot be used for drinking both because persion of pollutants) was evaluated by a coefficient K of bacterial pollution and the complete loss of condi- inverse with respect to MPA. At K < 0.8, the condition. In 2016, the average values of mineralization tions are unfavorable for dispersion; at 0.8 ≤ K ≤ 1.2, were 1.1 g/dm3 (at a standard of 2–3.5 g/dm3), the the conditions are moderately favorable for dispersion; concentration of dissolved carbon dioxide was and at K > 1.2, the conditions are favorable for the 0.3 g/dm3 (at a standard of 1.0–2.5 g/dm3). The well self-purification of the atmosphere. 5/0, represented in GOST R 54316-2011 [8] as Dolo- The processes dominating in the resort territory mite Narzan, fails to meet the requirements either by facilitate the accumulation of pollutants. Thus, the the main ionic composition or by mineralization long-term MPA is 2.04 for Kislovodsk, 1.22 for Essen- (3.0 g/dm3 at a standard of 4.0–4.5 g/dm3) [12]. tuki, 1.17 for Pyatigorsk, and 1.38 for Zheleznovodsk. The coefficient of atmosphere self-purification K was 0.49 for Kislovodsk, 0.82 for Essentuki, 0.85 for Pyat- FACTORS AND SOURCES OF THE ADVERSE igorsk, and 0.73 for Zheleznovodsk. EFFECT ON WATER RESOURCES The meteorological conditions for the dispersion OF CMV REGION of pollutants are unfavorable (Kislovodsk, Zhelezno- The causes of surface water pollution, quality vodsk) and moderately favorable (Esentuki, Pyatig- losses, and the microbiological pollution of mineral orsk). As pollutants accumulate in the atmosphere, waters are related to both natural features of the CMV they also accumulate in soils in considerable amounts region and the higher anthropogenic load. and later they are transported by snowmelt and rain Natural factors. The CMW region with an area of water into the top aquifer, from which they enter the 5.3 thous. km2 represents all major forms of relief. The aquifers under development because of the closed diversity of the relief causes differences in the climate hydraulic interaction between them. of resort cities and has an effect on the redistribution An important feature is the steadily growing pre- of pollutants through the atmosphere. In rough hilly cipitation. According to instrumental observation data terrains (Essentuki, Pyatigorsk) ascending and from Kislovodsk weather station, the atmospheric descending air motions form on the windward and precipitation showed a steady increasing trend in the downwind slopes, respectively. Ground level concen- period from 1947 to 2016 at an average rate of trations increase at descending and decrease at 2.9 mm/year (Fig. 1), a fact, which is of importance. ascending air flows. The most unfavorable relief form The inflow of atmospheric water, which has a minimal is depression (Kislovodsk), where air stagnates, result- mineralization (up to 0.2 g/dm3), leads to a loss of the ing in the accumulation of pollutants near land sur- quality of mineral composition and carbon dioxide of face; this effect is especially significant for low emis- mineral water. This effect is especially pronounced in sion sources (motor transport). the southern part of the region where the aquifers The climate conditions at each resort agglomera- under development are closest to land surface [12, 14]. tion have significant specific features. The main cli- By the complexity of the geological structure and mate factors that influence the rate of dispersion and hydrogeological conditions, the Kislovodsk, Essen- accumulation of technogenesis products include: solar tuki, Pyatigorsk, and Zheleznovodsk mineral-water radiation, which governs the photochemical transfor- deposits are referred to the maximal 4th group of com- mations of pollutants and the formation of secondary plexity [24], because of their extremely complex geo- products of air pollution; precipitation amount and logical structure and the hydrogeological, gas-hydro- the duration of its events, leading to washing of pollut- chemical, and geological conditions. A characteristic ants out of the atmosphere; wind speed and the recur- feature of CMW region is the abrupt planar and verti- rence of calms; and the number of days with fogs. cal occurrence of collectors of fractured zones in rocks According to zoning of RF territory by the conditions with different genesis. The basement is intersected by of pollutant dispersion and the potential of atmo- a system of faults and disturbed by acid intrusion.

WATER RESOURCES Vol. 46 No. 2 2019 216 POMELYAIKO, MALKOV

W, mm/year W, mm Linear W, mm 1200

1000 y = 2.8627x + 536.29

800

600

400

200

0 2012 1974 2010 2014 1972 1978 1950 1952 1958 1960 1962 1966 1968 1970 1976 1980 1982 1986 1988 1992 1996 1998 1954 1956 1984 1948 1964 1990 1994 2000 2002 2008 2006 2004 Years

Fig. 1. Dynamics of precipitation by data of Kislovodsk weather station.

The main conclusion is as follows: the natural fac- the main ions of river water (K+, Ca2+, Na+, Mg2+, tors of CMW resorts feature high environmental haz- − – ard and facilitate the penetration and accumulation of HCO3 , and Cl ); indicators, characterizing water pollutants and dilution of production aquifers. self-purification capacity (BOD5, dissolved oxygen, pH, permanganate oxidability); heavy metals (HM) Anthropogenic factors. We consider the effects that – 2+ 2+ 2+ 2+ 2+ 2+ 6+ wastes from unsewered area in resort towns and leak- (Pb , Hg , Cd , Zn , Ni , Mn , Cu , Cr ); + − ages from the utility networks of different destination indicators of different types of pollution (NH4 , NO2 , produce on surface water and groundwater. The wear − 2− NO3 , NF, phosphates, SO4 , Al, Se, phenols); com- of the sanitary–engineering infrastructure averages 60 2+ 2+ for water-supply network, 70 for sewage network, and ponents with higher background (Ba , Sr , Fe); toxic inorganic substances (Be2+, Br–, F–, As,); char- 80% for storm drainage [22]. The total leakage incor- α β porates three components, i.e., leakage from water- acteristics of radiation safety (total - and -activity) supply network, losses from sewage (collecting) sys- [17, 18]. The sampling for chemical analyses was car- tem, and wastewater from unsewered populated areas. ried out in accordance with GOST 31861-2012. Microbiological studies of water included the determi- Wastewaters show the concentrations of heavy nation of the number of mesophilic aerobic and facul- metals, phosphates, nitrogen-containing compounds, tatively anaerobic microorganisms, coliforms, and oil products, surfactants, etc. several times greater fecal coliforms, and Pseudomonas aeruginosa. Water than the respective MACs. Technogenic watering samples for microbiological analysis were taken in caused an increase in the seismicity of urban areas accordance with GOST ГОСТ 31942-2012. When because of changes of soil category in terms of seismic water contained two or more substances of the 1st– properties from the second to the third. According to 2nd hazard classes with similar mechanisms of toxic data of 1994, areas with seismicity 9 accounted for 18% effect, a limiting hazard factor (LHF) was calculated of the territory, while data of 2006 show such area to for each sample. The MAC was taken to be the tightest reach 75% [10]. of the following standards: Order no. 20 of January 18, 2010, developed for water bodies used for fishery [23], RIVERS IN CMW REGION and GN 2.1.5.1315-03 [7] for cultural-domestic water use. Surface water quality was assessed with the use of Environmental monitoring (EM) in CMW resorts well-known integral estimates WPI (water pollution covered the period from 2000 to 2016 when it was car- index) [13] and SVWPCI (specific value of water pol- ried out on the rivers of Belaya, Berezovaya, lution combinatorial index) [26]. WPI was calculated Ol’khovka, Alikonovka, Bugunta, Yutsa, and by six characteristics by the formula: Dzhemukha, flowing on the territories of resort towns. The measurements were carried out 1–2 times per N C MAC season with obligatory sampling during a freshet, dry WPI=  ii , season, and spring flood. The number of gages was 15 i=1 N in Kislovodsk, 4 in Essentuki, 4 in Zheleznovodsk, and 4 in Pyatigorsk. The chemical analysis of each where Ci is the concentration of the component; N is sample included the determination of 34 components: the number of characteristics used to calculate the

WATER RESOURCES Vol. 46 No. 2 2019 QUALITY PROBLEMS OF SURFACE WATER AND GROUNDWATER 217 index; MACi is the maximal allowable concentration Be, Br, Cr, and phenols were not recorded in river for the corresponding type of water object. water. The characteristics of radiation safety did not The set of characteristics included the concentra- exceed the established standards. tions of manganese, copper, lead, zinc, and nitrite The main pollution sources of mountain rivers are nitrogen and biochemical oxygen demand within 5 unsewered residential accommodation; agriculture; days (BOD5). The algorithm of SVWPCI calculation fuel stations in urban areas; motor and railroad trans- is given in [26]; it was calculated for 14 pollutants most port; untreated storm and industrial storm water; cem- widespread in the surface water at CMW resorts, eteries in the first water protection zone, and unautho- including Al, Ba, Fe, Cd, Mn, Cu, As, oil products, rized landfills [18, 19]. Ni, NO2, Pb, Sr, Zn, phosphates, and BOD5 characteristic (Table 1). MINERAL GROUNDWATER Waters of all examined rivers were found to contain substances of 1st–2nd hazard classes: As, Cd, Hg, Pb, The joint effect of climatic and anthropogenic fac- Ni, Sr, Se, Ba, and nitrites in concentrations in excess tors on mineral water consisted in a systematic rise of of MACs. Their concentrations are up to 7 MAC for their dynamic levels and a drop in their salt content. As, up to 5 MAC for Cd; up to 4 MAC for Hg; up to We will illustrate this by the case of the Kislovodsk 2.7 MAC for Ba and Pb; up to 3 MAC for Ni; up to 8.5 Mineral Water Deposit [12, 20]. The results of regression analysis and the comparison with the actual val- MAC for Se; up to 3.6 MAC for NO2; and up to 17.5 MAC for Sr. All these substances, except for Sr and ues of level change in observation well network are Ba, which show higher natural concentrations in soils shown in Fig. 2. The coefficients of regression equa- in the region, enter river water because of human eco- tion for each observation well are given in Table 3. nomic activity. Notwithstanding the relatively large water intake Water quality classification by the annual average from operation wells, the observation wells show values of WPI and SVWPCI is given in Table 2. almost ubiquitous increase in dynamic levels. Depending on the obtained WPI, water bodies of The tendency is inverse for the total mineralization the CMW region were classified by the pollution and carbon dioxide (CO2). Chronological plots degree in the following manner: clear (1.6% of all sam- demonstrate the predominant decrease in the concen- ples), moderately polluted (23.8), polluted (66.7), trations of the major ions and CO2 (Fig. 3). Almost all dirty (3.2), and very dirty (4.8%). wells show a decrease in total mineralization and the concentration of carbon dioxide. This effect was most The samples of river water were dirtiest at the peak vivid in the water of well 5/0-bis. The mineralization of dry season. 3 dropped from 1.8–2.0 to 1.1 g/dm ; and CO2 concen- Water at river sources corresponds to the II quality tration, from 1.0 to 0.3 g/dm3, resulting in that water class (clear). Such water is admissible for fishery and changed its status from mineral to fresh. The only cultural-domestic use. River water at the mouths cor- exception is well no. 23, where the total mineralization responds to the IV and V quality classes—polluted and 3 dirty. Such water is inadmissible for fishery and cul- increased from 5.5 to 7.0 g/dm . These processes are a tural-domestic use. consequence of the input into aquifers of large amounts of fresher waters of atmospheric origin and River waters do not meet hygienic standards by wastewaters from unsewered settlements. The latter microbiological characteristics. The share of substan- are a source of bacterial pollution of mineral waters. dard samples may reach 94%, depending on the sea- The hydrodynamic and hydrogeochemical regimes of son. the operation of wells shows a considerable effect of Sixty-four percent of samples fail to meet standards their hydraulic interaction, because of which, to in terms of LHV. The largest characteristic (20.93) was improve the accuracy of the assessment of the long- obtained at the mouth of the rivers of Belaya and term trends, hydraulic method of forecasting in com- Alikonovka, where the concentrations of a largest bination with multidimensional regression number of pollutants of the 1st–2nd hazard class (Cd, analysis were used. The process of formation of the As, Pb, Sr) was recorded. dynamic level in wells can be described by a hydraulic River water was found to contain substances of the equation [2]: 1st–2nd hazard class: As, Hg, Cd, Pb, Ni, Sr, Se, Ba, ∇Q =−−Qi j − and NO2 in concentrations in excess of MAC. The HHtt0  h, (1) most common pollutants of river water are Al, Sr, Pb, qqiij Ni, phosphates, sulfates, oil products, and nitrogen where H is the current value of the dynamic level; H compounds. t 0 is the initial position of the level; Qi, qi are the yield The presence of anthropogenic load distinctly cor- and specific yield of the well; Qj, qij is the yield of the relates [18, 19] with the appearance of specific accom- remote jth well and the coefficient of interaction of the panying pollution type in rivers further downstream. jth well with the ith well under consideration; ht is the

WATER RESOURCES Vol. 46 No. 2 2019 218 POMELYAIKO, MALKOV

Table 1. Ranges of the concentrations of some pollutants in rivers of CMV resources Pollutant concentration in rivers, мg/dm3 Characteristic average (Сav) minimal (Сmin) maximal (Cmax) Kislovodsk (rivers of Berezovaya, Belaya, Ol’khovka, and Alikonovka) Arsenic 0.02 <0.001 0.07 Oil products 0.10 <0.02 0.25 Strontium 1.64 0.2 7.0 Nitrites 0.10 <0.02 0.29 Cadmium 0.005 <0.0001 0.007 Zinc 0.015 <0.01 0.04 Lead 0.01 <0.005 0.02 Copper 0.003 <0.001 0.007 Nickel 0.01 <0.001 0.03 Aluminum 0.20 <0.01 0.55 Manganese 0.10 <0.001 0.15 Iron 0.15 <0.05 0.98 Barium 0.62 0.10 2.96 Phosphates 0.05 <0.05 0.21

BOD5 2.30 0.50 5.70 Zheleznovodsk (Dzhemukha R.) Arsenic 0.002 <0.001 0.005 Oil products 0.10 <0.02 0.20 Strontium 0.67 0.49 1.14 Nitrites 0.12 0.05 0.25 Cadmium 0.002 <0.0001 0.006 Zinc 0.02 <0.01 0.06 Lead 0.006 <0.005 0.01 Copper 0.002 <0.001 0.005 Nickel 0.007 <0.001 0.02 Aluminum 0.26 <0.01 0.29 Manganese 0.07 <0.001 0.15 Iron 0.18 <0.05 0.30 Barium 0.50 0.20 0.97 Phosphates 0.29 <0.05 0.38

BOD5 1.10 0.30 4.10 Essentuki (Bugunta R.) Arsenic 0.026 <0.001 0.05 Oil products 0.19 <0.02 0.5 Strontium 0.35 0.51 9.3 Nitrites 0.15 0.04 0.98 Cadmium 0.005 <0.0001 0.0086 Zinc 0.015 0.008 0.05 Lead 0.010 <0.005 0.045 Copper 0.015 <0.001 0.047 Nickel 0.03 <0.001 0.045 Aluminum 0.15 <0.01 0.23

WATER RESOURCES Vol. 46 No. 2 2019 QUALITY PROBLEMS OF SURFACE WATER AND GROUNDWATER 219

Table 1. (Contd.) Pollutant concentration in rivers, мg/dm3 Characteristic average (Сav) minimal (Сmin) maximal (Cmax) Manganese 0.45 <0.001 0.65 Iron 0.15 <0.05 0.30 Barium 0.60 0.15 1.05 Phosphates 0.14 <0.05 0.38

BOD5 1.75 0.20 4.70 Pyatigorsk (Yutsa R.) Arsenic 0.006 <0.001 0.02 Oil products 0.30 <0.02 0.78 Strontium 0.85 0.18 6.4 Nitrites 0.16 0.04 1.15 Cadmium 0.006 <0.0001 0.008 Zinc 0.025 <0.01 0.039 Lead 0.012 <0.005 0.028 Copper 0.035 <0.001 0.082 Nickel 0.009 <0.001 0.12 Aluminum 0.26 <0.01 0.29 Manganese 0.07 <0.001 0.15 Iron 0.18 <0.05 0.30 Barium 0.50 0.20 0.97 Phosphates 0.29 <0.05 0.38

BOD5 1.10 0.30 4.10

Table 2. Classification of river water quality in CMW resorts over long-term period by the values of WPI and SVWPCI Section Quality class (WPI) Quality class (SVWPCI) Belaya R. (Kislovodsk) Source (Kurortnyi park) II class, clear, WPI = 0.81 1 class, conventionally pure, SVWPCI = 0.7 Mouth (ODZ) VI class, very dirty, WPI = 8.68 4 class, category “c”, very dirty, SVWPCI = 5.43 Dzhemukha R. (Zheleznovodsk) Zavodskaya str. (wasteland) III class, moderately polluted, 3 class, category “b”, very polluted, WPI = 1.21 SVWPI = 2.75 Lenina str. V class, dirty, WPI= 4.38 4 class, category “a”, dirty, SVWPI = 4.20 Bugunta R. (Essentuki) Tukhachevskogo str. III class, moderately polluted, 3 class, category “b”, very polluted, WPI = 1.56 SVWPI = 3.09 Ust’e (ODZ) VI class, very dirty, 4 class, category “b”, WPI = 6.52 dirty, SVWPI = 5.60 Yutsa R. (Pyatigorsk) 2 liniya str. III class, moderately polluted, 3 class, category “b”, very polluted, WPI = 1.94 SVWPI = 3.10 Ust’e (Esaul’skaya str.) VI class, very dirty, 4 class, category “c”, very dirty, WPI = 9.89 SVWPI = 5.15

WATER RESOURCES Vol. 46 No. 2 2019 220 POMELYAIKO, MALKOV

Habs, m Well 57 822

821

820 Meas. Calc. 819 Oct. 1989 Oct. 1993 Oct. 1997 Oct. 2001 Oct. 2005 Oct. 2009 Oct. 2013 Date H , m abs Well 78

822

821

820 Oct. 1989 Oct. 1993 Oct. 1997 Oct. 2001 Oct. 2005 Oct. 2009 Oct. 2013 Date Habs, m Well 79

822

821

820

819 Oct. 1989 Oct. 1993 Oct. 1997 Oct. 2001 Oct. 2005 Oct. 2009 Oct. 2013 Date Habs, m Well 94 833

828

823

818 Oct. 1989 Oct. 1993 Oct. 1997 Oct. 2001 Oct. 2005 Oct. 2009 Oct. 2013 Date

Fig. 2. Comparison of calculated and actual levels in observation wells of the Kislovodsk Mineral Water Deposit. temporal drop in the level. The symbol ∇ implies the ditions, the drop can be represented by a linear rela- exclusion of the ith well from the sum. tionship with an error of ≤20%, and equation (1) The relationship (1) shows that the change in the transforms into level in the well under consideration is a sum of instan- ∇Q taneous drops resulting from the operation of all inter- =−−Qi j − HHt 0  Vt, (2) acting wells and a temporal drop, the character of qqiij which is determined by the boundary conditions of the where V is the long-term average rate of level change, aquifer. The drop (ht) can develop in time by a loga- rithmic, exponential, linear, or more complex rela- taking into account the combination of pumping out, tionship, depending on the configuration of boundar- infiltration, and leakages from networks; t is the cur- ies in the planar or vertical section and the aquifer rent time. recharge conditions. When a relatively long observa- Equation (2) was solved with the use of multidi- tion periods are involved, whatever the boundary con- mensional regression analysis. A first-order linear

WATER RESOURCES Vol. 46 No. 2 2019 QUALITY PROBLEMS OF SURFACE WATER AND GROUNDWATER 221

Table 3. Coefficients of regression equation by observation wells (b0 is the initial value of the parameter under consideration at the moment taken as zero; bSpr, b5/0, b5/0-bis, b107D are the coefficients of influence of Narzan spring and operation wells (5/0, 5/0-bis, 107D) on observation wells; bw is the coefficient of the influence of infiltration on level dynamics in observation wells; Vt are the average long-term rates of level variations in observation wells)

Well no. b0 bSpr b5/0 b5/0-bis b107D bw Vt, m/month 57 819.23 0.00060 –0.00080 –0.00050 –0.00008 0.0045 0.0037 78 820.22 0.00043 –0.00202 –0.00060 –0.00012 0.0036 0.0043 79 819.81 0.00046 –0.00278 –0.00170 0.00000 0.0054 0.0047 94 820.47 0.00038 –0.00100 –0.00210 –0.00048 0.0047 0.0053 regression model with several independent variables tions used mean monthly levels and the yields of the was considered. most water-abundant groundwater intake structures. The hydrodynamic regime of the deposit. The regime The multifactor analysis should satisfy several condi- of the Kislovodsk deposit of carbon dioxide water was tions: the number of observation points should be 6– analyzed based on the data of observation wells. 10 times greater than the number of variables; the ratio The regularities of level dynamics were studied by of max/min factors should be not less than 2; the equation (2). The main objective was to establish the model should be checked for statistical stability. A lin- regularities in dynamic level variations in observation ear first-order model with six independent variables wells as a function of loads onto operation wells and was considered. The least-squares method yields the long-term regional rates of level drop. The calcula- following system of equations [9]:

Hn+++ b Q b Q b Q +++= b  Q b W bt  H  01ubct 25354 5 6 ++2 + + + + = H01 QbQbuu 253545 QQbQQb u u QQbQWbQtQH ucu 6 uut  ++++++=2 HQbQQbQbQQbQQbQWbQtQH0515ubct 2535545   55  65  5  (3) ++++++2 = HQbQQbQQbQbQQbQWb0515bbub 2553545   b bcb 55 65 Qtbbt QH 5  +++ +++=2 HQbQQbQQbQQbQbQWbQtQH01ccuc 253545   cbc  c 6  cct  +++ +++=2 H01 WbWQbWQbWQbWQbWubct 253545  bWtWH 6 ,

where H0 is the position of the level at the beginning of contour lines bi and to evaluate the degree of interac- the calculation t; b1, b2, b3, b4 are well interaction coef- tion between operation wells. ficients; b5 is infiltration recharge coefficient; b6 is Hydrogeochemical regime of the deposit. The infiltration trend coefficient; Qu, Q5, Q5b, Qc are mean regime was also analyzed with the use of linear multi- monthly yields of wells 5/0, 5/0-bis, 107, 107D; W is factor regression analysis by relationship (4), but oper- the recharge rate of aquifers, which incorporates the ation wells were analyzed in this case. The regime was effects of infiltration, leakages, and evaporation from assessed by the values of the total mineralization and groundwater surface; t is current time (in months). CO . The analysis included the evaluation of the coef- The reference time is the year of 1990, because the 2 hydraulic characteristics of the zone around the ficients of constraint equation to establish the contri- source have radically changed after decolmatation. bution of each factor to the dynamics of mineral composition. The calculations were made assuming a lin- The system of equation (3) was solved with the use ear dependence of the rates of changes in the of Gauss procedure. The results of regression analysis qualitative characteristics over time. The solution of and the comparison with measured data are given in the problem yielded the coefficients of the constraint Fig. 2. Practically all observation wells show a long- equation for the wells in the valanzhinskii and titonskii term increase in the dynamic levels with a rate of 1.0 to aquifers, which are given in Tables 4, 5. 6.0 cm/year. This is an effect of climatic and anthropogenic factors. We can agree with the opinion that The following model was considered: the coefficient of regression equation (bw) takes into mmbQ=+ + ∇+ bQVt. (4) account climatic, but not anthropogenic factors; how- tiijjm0 ever, the character of their effect is similar to that of The physical meaning of parameters in infiltration. The coefficients at wells allow one to con- equation (4) is analogous to that of equation (2). The struct the zone of influence of each well in the form of solution is given in graphical form (Fig. 3). The agree-

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3 3 M, g/dm CO2, g/dm Well 5/0-bis Well 5/0-bis 2.0 0.8 1.5 0.6 1.0 0.4 0.5 0.2 Meas. Calc. Meas. Calc. 0 0 1965 1975 1985 1995 2005 2015 1965 1975 1985 1995 2005 2015 3 Date 3 Date M, g/dm Well no. 5/0 CO2, g/dm Well 5/2 4 3.0 2.5 3 2.0 2 1.5 1.0 1 Meas. Calc. 0.5 0 0 Meas. Calc. 1965 1975 1985 1995 2005 2015 1965 1975 1985 1995 2005 2015 3 3 M, g/dm Date CO2, g/dm Date 4.5 Well 7 3.0 Well 7 4.0 2.5 3.5 2.0 3.0 2.5 1.5 Meas. Calc. Meas. Calc. 2.0 1.0 1965 1975 1985 1995 2005 2015 1965 1975 1985 1995 2005 2015 3 3 M, g/dm Date CO2, g/dm Date 7 Well 23 3.0 Well 23 6 2.5 5 2.0 4 3 1.5 Meas. Calc. Meas. Calc. 2 1.0 1965 1975 1985 1995 2005 2015 1965 1975 1985 1995 2005 2015 M, g/dm3 3 Date CO2, g/dm Date 8 Well 1-OP 3.0 Well 1-OP 7 2.5 6 2.0 5 4 1.5 Meas. Calc. Meas. Calc. 3 1.0 1965 1975 1985 1995 2005 2015 1965 1975 1985 1995 2005 2015 Date Date

Fig. 3. Comparison of calculated and measured values of mineralization and carbon dioxide concentration by operation wells in the Kislovodsk Mineral Water Deposit.

ment between the calculated and measured data is rel- well 7, where CO2 concentration was found to atively high; the calculated root-mean-square devia- increase. The total mineralization of water of titonskii tion shows that the calculation error never exceeds aquifer (well 1-OP, 23) tends to increase, but the con- 16%. centration of CO2 here also decreases. Analysis of the coefficients suggests that the water The main source of balneotherapy in Kislovodsk is of the valanzhinskie subaquifers show a ubiquitous the Narzan spring. Its spouting would meet all drop in the total mineralization and a decrease in the demands of the resort complex, if its water did not concentration of carbon dioxide. The only exception is have a poor sanitary-microbiological condition. To

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Table 4. Coefficients of regression equation for wells of the valanzhinskii aquifer (m0 is the initial value of the parameter at the moment taken as zero; bSpr, b5/0, b5/0-bis, b107D, b107 are the coefficients of the influence of Narzan spring and operation wells (5/0, 5/0-bis, 107D, 107) on the mineralization and carbon dioxide in the analyzed wells; Vm are long-term average rates of changes in mineralization and carbon dioxide in the analyzed operation wells) 3 Springs m0 b5/0 b5/0-bis bSpr b107D b107 Vm, g/dm /year d, % rmsd Groundwater mineralization, g/dm3 Well 5/0-bis 3.072 –0.00181 –0.00068 –0.00045 –0.00021 0.00026 –0.0210 8.04 Well 5/0 6.792 –0.00188 –0.00141 –0.00088 –0.00050 0.00591 –0.0596 7.14 Carbon dioxide concentration, g/dm3 Well 5/0-bis 1.356 –0.00133 –0.00013 –0.00017 0.000158 0.00039 –0.0153 15.59 Well 5/0 3.784 –0.00033 –0.00060 –0.00036 –0.00019 0.00201 –0.0328 7.56

Table 5. Coefficients of regression equations for the titonskii and nizhnevalanzhinskii aquifers (bw is the coefficient of influence on the parameter of the well; bN is the generalized coefficient of influence of wells of the Northern flank of the Central Area (well 107D, well 107) on the wells under consideration) 3 Spring m0 bw b5/0 b5/0-bis bSpr bN Vm, g/dm /year d, % rsmd Groundwater mineralization, g/dm3 Well 1-OP 5.524 –0.06019 0.00287 –0.00022 0.000290 –0.00020 0.02108 3.40 Well 23 5.684 –0.26108 –0.00075 0.00068 0.000030 0.00112 0.00956 4.72 Well 7 4.294 0.0468 –0.00013 –0.00023 0.000127 –0.00039 –0.0193 2.32 Carbon dioxide concentration, g/dm3 Well 1-OP 2.443 0.02853 –0.00040 0.00006 0.000130 0.00022 –0.0207 4.64 Well 23 3.267 –0.07415 –0.00039 0.00005 0.000060 0.00024 –0.0340 3.78 Well 7 1.436 –0.1267 0.00034 0.00089 0.00024 –0.00012 0.00128 7.39 neutralize it, silver sulphate is added into the mineral Area. The water of the Upper Valanzhinskii subaquifer water before its supply to the bathes. The applicability are subsoil water and show a hydraulic interaction with of this method is not obvious as silver is a heavy metal, surface water and infiltration water. The majority of which is assigned 2nd hazard class in Russia, i.e., a unsewered settlements is situated in this zone. How- highly hazardous substance. Silver is slowly removed ever, the most unfavorable is the zone of maximal haz- from the organism and can accumulate in liver, kid- neys, skin, and mucous membranes. Resorption ard, located southeast of the Narzan spring. To through skin is possible. At the concentrations allowed improve the quality of mineral water, it will suffice to by the standards now in force (50 μg/dm3), silver in construct a drainage system around the spring. The water has but a bacteriostatic effect, i.e., it can only system is to consist of four wells with depths from 30 to inhibit bacterial growth. The ability to reliably kill 60 m, which drain the Upper Valanzhinskii and Qua- some bacteria is typical of silver in concentrations ternary aquifers, combined by a common collector. >150 μg/dm3, which amounts to 3 MAC, hence a The main objective of the drainage system is to health hazard. According to data of WHO, for silver to decrease the level along its axis by 4.0 m. In this case, have a bacteriostatic effect requires several conditions a local depression that will form south of the spring to be met: the water is to have a good microbiological will collect the pollutants that pass through the Upper quality; the input of new bacteria into water is to be Valanzhinskii subaquifer, as well as fresh water, and prevented; the water is to be kept in the dark, because the effect of light can cause precipitation and change discharge them into a sewage collector; i.e., a part of in the color. In addition, silver ions inhibit the growth fresher polluted water of the Upper Valanzhinskii sub- of far from all bacteria. aquifer in the spring will be intercepted by the drainage A method is known that can considerably improves system. This will reduce the yield of the spring, but its the qualitative characteristics of spring water. Figure 4 water will become much more mineralized and bacte- gives a map of the ecological–hydrogeological zoning riologically pure; in addition, this will improve the of the territory of Narzan spring area. The zone of high water quality in the Ol’khovka River, into which water pollution hazard covers nearly half of the Central from the spring is being discharged now.

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Scale 1 : 20 000 0 200 400 600 800 m

–20 200 m in 1 cm Belaya R. 107D

87 Contour lines of the difference between 20 the elevations of land surface and valanzhinskie groundwater level –10 0 20 Berezovaya R.

20 2-T 10 Well and its number

20 Zone of high level of protection of subsoil water 10 5/0 30 40 Zone of relative protection against pollution. 50 Aeration zone greater than 10 m 60 Narzan Spr. Zone of high hazard of pollution by subsoil water. Valanzhin level position 2–10 m below land surface

Zone of maximal hazard

Berezovaya R. Groundwater ﬂow direction

Drainage system Ol’khovka R.

Fig. 4. Schematic map of ecological–hydrogeological zoning of Narzan spring.

CONCLUSIONS trends in the dynamics of the natural and anthropogenic factors over the recent half a century, the ecolog- Analysis of the data of long-term environmental ical situation at CMW resorts should be expected to monitoring suggests the conclusion that the situation deteriorate. with water resources in CMW resorts is critical. This manifests itself in the presence of substances of the 1st and 2nd hazard classes in concentrations in excess of REFERENCES MAC in river and subsoil water, bacteriological pollution of upper aquifers, the rise of dynamics levels, and 1. Bezuglaya, E.Yu. and Smirnova, I.V., Vozdukh gorodov a drop in the salt content of mineral water of the aqui- i ego izmeneniya (Urban Air and Its Changes), fers under development. This is a result of the disre- St. Petersburg: Asterion, 2008. gard of obvious facts. “Everything should disappear in 2. Bochever, F.M., Teoriya i prakticheskie metody gidro- some way”—this is an axiom, which requires no proof. geologicheskikh raschetov ekspluatatsionnykh zapasov At the same time, the construction of fuel stations is in podzemnykh vod (Theory and Practical Methods of progress in the territories of resort towns; a thermal Hydrogeological Calculations of Groundwater Stor- power station is being constructed in the lowest point age), Moscow: Nedra, 1968. of a close depression in the zone of higher potential of 3. General’nyi plan goroda Essentuki (General Plan of atmospheric pollution. The amount of motor trans- Essentuki City), Moscow: Giprogor, 2009, vol. 1. port in the resorts is steadily growing. It accounts for 4. General’nyi plan gorodskogo okruga goroda-kurorta 96% of atmospheric emissions. In the XXI century, up Zheleznovodsk Stavropol’skogo kraya (General Plan of to 40% of urban territory is still unsewered. The the Urban District of Zheleznovodsk Resort City, Stav- unsewered areas coincide with the sites of shallow ropol’skii krai), St. Petersburg: RosNIPIUrbanistiki, depth to mineral water (the aeration zone is ~5 m in 2013, vol. 2, Book 1; General Plan of the Urban District thickness). The situation is becoming even worse, as of Kislovodsk Resort City, Moscow: Giprogor, 2011, the population (and, therefore, wastewater volumes) is vol. 1. increasing, while the utility networks are not develop- 5. General’nyi plan munitsipal’nogo obrazovaniya goroda- ing and, practically, receive no repair. Considering the kurorta Pyatigorska (General Plan of Municipal Unit

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Pyatigorsk Resort City. http://pyatigorsk.org/139. 18. Pomelyaiko, I.S. and Kovalenko, N.N., The status of a Cited July 15, 2017. federal resort—a privilege or a punishment?, in Tekhno- 6. GN 2.1.5.1315-03. Predel’no dopustimye kontsentratsii gennye Protsessy v gidrolitosfere. Sb. statei. 2-go nats. (PDK) khimicheskikh veshchestv v vode vodnykh nauch. foruma “Narzan-2013,” (Technogenic Pro- ob’’ektov khozyaistvenno-pit’evogo i kul’turno-bytovogo cesses in Hydrolithosphere. Coll. Pap. 2nd Sci. Forum vodopol’zovaniya (Maximal Allowable Concentrations Narzan-2013), Pyatigorsk, RIA-KMV, 2013, pp. 187– (MAC) of Chemicals in Water of Water Bodies of 214. Domestic and Cultural-General Water Use), Moscow: 19. Pomelyaiko, I.S., Malkov, A.V., and Pershin, M.I., Minzdrav RF, 2003. Hydromineral base of the Kislovodsk mineral carbon 7. GOST (State Standard) R 54316-2011: National Stan- dioxide deposit: problems and the ways of their solu- dard. 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