The general characteristics and organic matters of therapeutic mud from Lake Noot (Mongolia)

12 In this investigation, we examined the chemical composition, physicochemical properties, and organic matter of therapeutic mud from Lake Noot in the Arkhangai province of Mongolia. The therapeutic mud from “Lake Noot” is used in the pelotherapy 15 of local health care services for some time but without deep characterization. Due to this, a study of therapeutic mud samples was required. Our research concentrated on identifying general characteristics, organic matter, 18 mineralogical, and chemical composition of therapeutic mud at two different Lake Noot sites. Results showed that the therapeutic mud belongs to the continental hydrogen sulfide sticky mud type. The total organic matter in the therapeutic mud of Lake Noot 21 was 14.44%. Total organic matter contains a humic substance of 42.17%, lipid 16.62%, and carbohydrate 7.13%. A total of 172 compounds were identified in the dissoluble organic matter of therapeutic mud, mainly of natural origin, using the gas 24 chromatography-mass spectrometry (GC/MS) method. The dominant compounds were saturated and unsaturated hydrocarbons with 13–44 carbon atoms and carboxylic acids and their ethers. Some of the identified organic compounds have 27 been reported antimicrobial, anti-inflammatory, antibacterial, and antifungal properties.


INTRODUCTION
Since ancient times humanity has used therapeutic mud; however, we did not utterly 36 understand its composition and properties until the nineteenth century. Back then, countries have been intensively studied the composition and biological activity of therapeutic mud in their respective territories. Lately, there were many studies worldwide 39 to determine the essential physicochemical characteristics of therapeutic muds in various spa centers [1][2][3]. Mongolian scientists started research in this field in the 1950s; however, mineral spring's research has developed, and therapeutic muds study was abandoned. 42 Mongolia is a Central Asian country with an extreme continental climate. It has a remarkable abundance and variety of lakes, some large enough to be classified among Eurasia's largest [4]. In Mongolia, natural therapeutic muds used in pelotherapy are 45 abundant, and people used them in traditional medicine to treat pains. However, the exact composition of therapeutic mud is less studied. In this study's framework, analyses were carried to assess Lake Noot's therapeutic mud suitability for therapeutic use. This report 48 aims to determine the chemical composition, physicochemical properties, and some organic compounds of natural therapeutic mud from Lake Noot in Mongolia's Central region. The study of therapeutic mud from Lake Noot is part of a project to characterize 51 Mongolian therapeutic mud deposits [5]. Result of this research is expected to increase local spa-centers' opportunities to engage in entrepreneurship of medical tourism uses natural resources.

EXPERIMENTAL
Sampling area and material: Lake Noot (geographic coordinates 99°49'E; 48°07'N) is 57 located in Tariat soum of Arkhangai province in the Central region of Mongolia. Lake Noot is at an altitude of 2064 m and has a surface area of about 211 ha with a length of 2.2 km, a width of 1.7 km, an average depth of 3.5 m, and a volume of 2.9 million m 3 [6].

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Therapeutic mud samples were collected from 2 different parts (southeast 99°52'E; 48°07'N and southwest 99°51'E; 48°06'N) of Lake Noot.  The major elements were determined by X-ray fluorescence analysis (XRF), using the Axios Max equipment. The concentrations of minor elements were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES) using the Agilent 90 ICP-OES 5110 equipment. All the analytical work was conducted at the laboratories of the ALS geochemistry laboratory.

Determination of organic components:
The organic components were extracted from 93 dried therapeutic mud that preliminary washed with distilled water to clean from salts and air-dried. The lipid fraction was extracted by a mixture of chloroform/ethanol (1:1) [9]. The humic substance was extracted with 0.2N NaOH after the demineralization by 10% 96 hydrochloric acid. Carbohydrates were extracted by water at 40-50°C and purified using dialysis bags [10].
Free organic components were extracted using the Soxhlet apparatus, and Soxhlet 99 extraction was performed with different solvents such as hexane, chloroform, acetone, and a mixture of ethanol/benzene (1:9). The solvents were evaporated by a rotary vacuum evaporator [11]. The extracted fractions were mixed and dissolved in chloroform. Dissolved 102 organic matter (DOM) in chloroform was analyzed using gas chromatography-mass spectrometry (GC/MS).

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Mass Spectrometry was performed using Thermo Scientific GC (Trace 1310) -MS (TSQ 8000). The GC-MS was fitted with a 30 m Agilent fused capillary column, DB-5ms 0.25mm, 0.25 mkm Filminitial temp 50 o C held for 1 min, then programmed at 8°C/min ramp to 108 300°C, the isothermal temperature was held for 30 min. The injection port temperature was 250°C, and 1 μL volume was injected into a splitless mode. Helium was used as a carrier gas at a constant flow of 1.5 ml/min, head pressure 9.10 psi. The mass spectrometer was 111 operated in an electron ionization mode with ion source temperature at 250°C. The organic compounds were identified by comparing chemical software, and databases were used to analyze the results MS Windows NIST Mass Spectral, NIST (NIST21, NIST 98).

RESULTS AND DISCUSSION
General characteristics of therapeutic mud from Lake Noot 117 We determined the general characteristics of therapeutic mud at two sites of Lake Noot (

Mineralogical and chemical composition of therapeutic mud from Lake Noot
The mineralogical analysis results are shown in Table 3 and Figure 2. The mineralogical 135 analysis of therapeutic mud from Noot Lake showed substantial amounts of primarily carbonate minerals (calcite) and albite, while quartz and anorthite were also determined.
138 Table 3. Mineralogical composition of therapeutic mud from Lake Noot The major and trace element composition is presented in Table 4, and the results are compared with the ranges of the continental crust [13].  The distribution and composition of individual organic compounds in DOM (dissolved organic matters) are summarized in Table 6. The GC/MS chromatogram of DOM from therapeutic mud in Lake Noot is shown in Figure 3.  other biomolecules [17]. These fatty carboxylic acids have also been reported to act as antioxidants and membrane regulators in their isolated form and show significant antiinflammatory activity [18].

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Another group of organic compounds comprised terpenoids and steroids, which accounted for 9.56% of the total composition, and it is derived from plant sources. DOM has contained dialkyl phthalates 3.2%, element sulfur 6.59%, sulfur-containing hydrocarbons 3.06%, and 234 oxygen-containing compounds 0.75%, respectively.
Previous studies and research identifies some of the identified organic compounds that have been reported in this paper as biological activities such as antimicrobial, anti-237 inflammatory, antibacterial, and antifungal (  Therefore, it can be suggested that the therapeutic properties of muds from the lake Noot is related with the presence of the biological active compounds in DOM.

CONCLUSION
The general characteristics and organic matters of therapeutic mud from Lake Noot in Bioactive compounds identified in the Lake Noot's mud could stand therapeutic properties of this mud.