APPLIED PHYSICS – ECOLOGY
INDUCTIVELY COUPLED PLASMA (ICP) AND TOTAL DISSOLVED SOLIDS (TDS) MEASUREMENTS OF SURFACE WATERS FROM IALOMIÞA RIVER C. STIHI1, I. V. POPESCU1, A. BANCUTA1, V. STIHI1 and GH. VLAICU2 1
Valahia University of Târgoviºte, Faculty of Sciences, Physics Department, 2 Carol I street, Târgoviºte, Romania, e-mail:
[email protected] 2 Special Steel Complex, Physics Laboratories, Târgoviºte, Romania Received December 21, 2004
In this work we intend to study the pollution level with heavy metals of water from Ialomiþa River, Damboviþa area. Different samples of surface water, collected at points with industrial sources of pollution from Damboviþa area, was measured with Baird ICP2070 Inductively Coupled Plasma spectrometer and with Hach CO150 conductivity meter. Using ICP spectrometer we have determined the elemental composition and the concentration of S, Cl, K, Fe, Zn, Br, Sr with a precision less then 6%. Using CO conductometer we have determined the total dissolved solids (TDS) in samples with a precision less then 1%.
1. INTRODUCTION
Inductively Coupled Plasma Spectrometry (ICP) [1] method is based on the fact that the atoms and ions produced in the plasma are excited and emit light. The intensity of light emitted at wavelengths characteristic of the particular elements of interest is measured and related to the concentration of each element from samples. This elemental analysis method can be successfully used to determine the elemental composition of different samples from environment like surface water. Total Dissolved Solids (TDS) are solids in water that can pass through a filter. TDS is a measure of the amount of material dissolved in water. This material can include carbonate, bicarbonate, chloride, sulphate, phosphate, nitrate, calcium, magnesium, sodium, organic ions, and other ions. A certain level of these ions in water is necessary for aquatic life. Changes in TDS concentrations can be harmful because the density of the water determines the
Paper presented at the 5th International Balkan Workshop on Applied Physics, 5–7 July 2004, Constanþa, Romania. Rom. Journ. Phys., Vol. 50, Nos. 9– 1 0 , P. 977–981, Bucharest, 2005
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flow of water into and out of an organism's cells (Mitchell and Stapp, 1992). However, if TDS concentrations are too high or too low, the growth of many aquatic lives can be limited, and death may occur. A high concentration of TDS may also reduce water clarity, contribute to a decrease in photosynthesis, combine with toxic compounds and heavy metals, and lead to an increase in water temperature. TDS can be estimated by measuring the specific conductance of the water. 2. EXPERIMENTAL
Different samples of surface water, from Ialomiþa river, collected at points with industrial sources of pollution from Damboviþa area (Table 1), was measured with Baird ICP2070 Inductively Coupled Plasma spectrometer and with Hach CO150 conductivity meter. Table 1 Samples from Ialomiþa River Sample cod Collecting points/ polluting sources P1
Dobreºti – Bucegi mountain area
P2
Moroieni-Mountain zone/Healthy sanatoria
P3
Pietroºiþa-Mountain zone
P4
Fieni – town – 30 km north from Târgoviºte town/cement factory, light sources factory
P5
Pucioasa – town – 20 km north from Târgoviºte town /textile factory
P6
Doiceºti – village area – 10 km north from Târgoviºte town/ energetic coal factory
P7
Târgoviºte – input town/Steel Special Trust, Romlux – light sources factory, Victoria-chemicals factory, PETROM – oil extraction trust
P8
Târgoviºte – output town /Steel Special Trust, Romlux – light sources factory, Victoria – chemicals factory, PETROM – oil extraction trust
The ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectroscopy) spectrometer used by us are a Baird ICP2070 – Sequential Plasma Spectrometer (Fig. 1) which consists of a sample introduction system, a plasma torch, a plasma power supply and an optical measurement system. The sample must be introduced into plasma in a form that can be effectively vaporized and atomised (small droplets of solution, small particles of vapour). The plasma torch confines the plasma to a diameter of about 18 mm. Atoms and ions produced in the plasma are excited and emit light. The intensity of light emitted at wavelengths characteristic of the particular elements of interest is measured and related to the concentration of each element from samples. Baird ICP2070 – Sequential Plasma Spectrometer use as a plasma gas Argon and the plasma is sustained in a quartz torch and the plasma is generated
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Fig. 1. – A schematic diagram of ICP spectrometer.
using a radio frequency generator at 40.68 MHz. Temperatures of 5000–9000 K have been measured in the plasma. The detection systems used are a sequential monochromator with a wavelength range (160–800) nm. The optical emission spectra are made using a personal computer.
Fig. 2. – Hach C0150 conductometer.
We used for TDS measurement a portable conductometer Hach CO150 (Fig. 2) with a cell constant K = 0.1 [2]. Together with conductivity and TDS measurements we perform salinity measurements.
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3. RESULTS AND DISCUSSIONS
Experimental results are presented in Table 2 and Table 3. Table 2 The concentration (ppm) of elements in samples from Ialomiþa River obtained using ICP method Element
P1
P2
P3
P4
P5
P6
P7
P8
S
28.50
27.25
29.33
37.18
58.24
35.40
32.20 35.80
Cl
51.30
60.12
62.25
49.51
50.82
50.17
45.3
K
10.02
9.20
11.73
9.50
7.20
7.0
7.20
8.35
48.22
Fe
0.05
0.27
0.12
0.12
0.10
0.21
0.18
0.18
Zn
1.18
1.72
1.45
1.12
1.70
1.38
1.38
1.25
Br
not detected
not detected
not detected
not detected
not detected
not detected
0.08
0.02
Sr
not detected
not detected
not detected
2.02
not detected
1.8
1.8
1.5
Table 3 Experimental results of conductivity, salinity and TDS measurements using Hach CO 150 conductometer Sample code
σ [μs]
Salinity [o/oo]
TDS [mg/l]
P1
266
0,1
128
P2
385
0,2
183
P3
404
0,2
191
P4
292
0,1
139
P5
416
0,2
199
P6
457
0,2
219
P7
533
0,3
255
P8
550
0,3
262
Using ICP spectrometry we determined the elemental composition of surface water and the concentration of different elements like: S, Cl, K, Fe, Zn, Br, Sr. In this study of our work the obtained results are points of depart in the study of different region of our area. The variation of Sr concentration cannot be explain at this moment because we must study the composition of stones from Ialomiþa river, different stones can have Sr in her composition. Using conductivity measurements we observe a TDS variation presented in Fig. 3. Surface water is an important component of fresh water systems. Surface water monitoring is essential to attaining a comprehensive understanding of the physical, chemical, and biological characteristics of aquatic systems.
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Fig. 3. – TDS variation along the Ialomiþa river – Damboviþa, area.
Increased total solids has a similar effect to turbidity in that water clarity is reduced, water temperature can rise, oxygen levels can fall as a result of less photosynthesis, and solids can bind to toxic compounds and heavy metals. So the experimental results obtained in this work will be preliminary dates for a future research programme of surface water monitoring . REFERENCES 1. R. W. J. M. Boumans, Inductively Coupled Plasma Emission Spectroscopy, John Wiley and Sons, New York, 1987. 2. CO150 Conductivity Meter – Instruction Manual. 3. Wu, Koch, Hamer and Kay, Review of electrolytic conductance standards. J. Soln. Chem, 1987, 16, 985–997.
