Hydrochemical and Physicochemical Monitoring of Ground water in North-West Region of Punjab , India-A Study Involving Analysis of Major Ions , Heavy Metal Ions and Other Related Parameters

The district of Tarntaran is situated in Punjab State of Northwestern part of Punjab, India covering 5059 Sq. Km area, located 45 km from Amritsar its geographical coordinates are 310 16' 51" north and 740 51' 25" East longitudes. Water samples are collected from 100 locations in 20 villages on the Patti –Khem Karan highway with 5 samples from each village, and were subjected to analysis for chemical characteristics. The type of water that predominates in the study area is Ca-Mg-HCO3 type, based on hydro-chemical analysis. Besides, suitability of water for irrigation is evaluated based on sodium adsorption ratio (SAR), residual sodium carbonate, sodium percent and salinity hazard. Other physicochemical parameters such as pH, TDS, conductance etc were also determined using water analysis kit. Analysis of water samples for heavy metal analysis was also carried out in the present study.

Monitoring the quality of water is one of the most important aspects in groundwater studies.The suitability of water for drinking, agriculture and industrial purposes is assessed by hydro chemical studies.Any natural or anthropogenic effect on water quality can also be studied if regular monitoring of water samples is carried out in a specified region.The most important one is hydrochemical study which determines the presence of ion such as Ca +2 , Mg +2 , Cl -1 , HCO 3 -1 Na +1 , K +1 , and SO 4 -2 in groundwater.Different criterion has been studied for deciding the suitability of water for various purposes.It was observed that the criteria used in the classification of waters for a particular purpose considering the individual concentration may not find its suitability for other purposes and better results can be obtained only by considering the combined chemistry of all the ions rather than individual or paired ionic characters [1][2][3][4][5] .
Classification of water based on these parameters is a big challenge as it requires the determination of concentration of various ions present in water and their interrelationships.In order to decide the quality of water that is suitable for a particular purpose, it important to evaluate and interpret its physical and chemical parameters.A number of techniques and methods have been developed to interpret the chemical data.Presentation of chemical data in graphical form makes understanding of complex groundwater system.Methods of representing the chemistry of water like Collin's bar diagram 6 , radiating vectors of Maucha 7 , and parallel and horizontal axes of Stiff 8 , have been used in many parts of the world to show the proportion of ionic concentration in individual water samples. 9Numerous methods have been developed by Subramanian to interpret the chemistry of ground water in coastal southern parts of India.The objective of the present work is to monitor the major ions present in underground water and to evaluate the ground water quality in northwest region of Punjab, India.In this case study the methods proposed by Back 10 and Hanshaw, Wilcox, Eaton, Todd 10 and USSL (US Salinity Laboratory) classification have been used.

Study Area
The district of Tarntaran is situated in northwest region of Punjab, India covering 5059 Sq Km Area..It is surrounded by district Amritsar in the north, Kapurthala in the east, Ferozepur in the South and Pakistan in the West.Patti town is a municipal council of the Tarntaran district, located 45 km from Amritsar with geographical coordinates 31 0 16' 51" north and 74 0 51' 25" east.Even though only limited region experience temperature below 0 0 C, ground frost is commonly found in majority of the areas in winter season.The temperature rises gradually with high presence of moisture and overcast sky.However, the rise in temperature is steep when sky is clear and moisture content is very less, falling within the semiarid region and frequently facing water scarcity as well as quality problems, so assessment of water quality becomes an important research concern.

Methodology Sampling, storage and preservation
Field visits were carried out to collect water samples from hundred locations in twenty villages

Fig. 1: location map Sample collection sites
on the Patti -Khem Karan highway with five samples from each village, and were subjected to analysis for chemical characteristics.These samples were collected in duplicates randomly from water sources (Hand-pumps/submersible pumps/public and private Tube wells) of the selected sites.The collected water samples were transferred into pre-cleaned polythene bottles for analysis of chemical characteristics.

Hydrochemical analysis of water samples
Chemical analyses was carried out for the major ion concentrations in water samples collected from different locations using the standard procedures recommended by APHA-1994 13 .The analytical data can be used for the classification of water for utilitarian purposes and for ascertaining various factors on which the chemical characteristics of water depend.Cations like calcium and magnesium were analyzed using volumetric method while sodium and potassium were analyzed by flame photometer, whereas anions like chloride and bicarbonate were analyzed by volumetric method while sulphate was analyzed by spectrometric method.

Physicochemical analysis of water samples
T h e o n s i t e a n a l y s i s o f v a r i o u s physicochemical parameters (such as pH, TDS, DO, Electrical conductance and salinity) was carried out using water analysis kit.The conductance and pH measurements were done using microprocessor based conductivity meter and pH meter (Systronics, India).The analysis of other parameters such as TDS, pH, DO etc was carried out for the classification of water for purposes other than agricultural use and also for ascertaining various factors on which the chemical characteristics of water depends [14][15][16][17] .

Analysis of water samples for Heavy metal ions
The analysis of heavy metal was carried out by emission spectrometer, ICAP 6300 (Thermo Electron Corporation) [18][19][20][21][22][23][24][25][26] .ICAP 6300 allows for simultaneous analysis of all elements from sub ppb to percentage level.The instrument is calibrated by using stock solutions of known concentration of heavy metals ions and various dilutions of stock solution.Analysis of a solution of known concentration is required to check the performance of the instrument.

Hydro-Chemistry
The assessment of hydro chemistry of ground water is important for its irrigational and domestic usage.Maximum and minimum  concentration of major ions present in the groundwater from the study area is presented in Table 1.

Cations
Cation concentration (Ca +2 , Mg +2 , Na + , K + ) in the groundwater samples come out to be much below the WHO limits (WHO 2011).Presence of calcium (Ca +2 ) and magnesium (Mg +2 ) ions in water is largely due to leaching of limestone, dolomites, gypsum and anhydrites.The concentration of Ca +2 is varied from 56.0 mg/l to 180.0 mg/l.(WHO limit 100 mg/l; WHO 2011).The concentration of Mg +2 ion varied from 24 mg/l to 56 mg/l.(WHO limit 30 mg/l; WHO 2011) similarly, the concentration of Na + ion varied from 61.9 mg/l to 178.9 mg/l.(WHO limit 175 mg/l; WHO 2011).The concentration of K + ion varied from 13.8 mg/l to 27.2 mg/l.(WHO limit 25 mg/l; WHO 2011)

Anions
The concentration of Chloride ion varied from 397 mg/l to 587 mg/l.(WHO limit 600 mg/l; WHO 2011).The bicarbonate ion concentration varied from 178 mg/l to 354 mg/l.The Sulphate ion concentration varied from 98 mg/l to 162 mg/l.(WHO limit 250 mg/l; WHO 2011).A number of correlation studies between various major cations and anions present in water were carried out to know the extent of availability of one type of ion in reference to other.

Piper Tri linear diagram
The Piper-Hill diagram 13 is used to infer

Chadha's diagram
The difference in milli equivalent percentage between alkaline earth metal ions (Ca +2 and Mg +2 )and alkali metal ions (Na + and K + ) expressed as percentage is plotted on the X-axis and difference in milli equivalent percentage between weak acidic anions(CO 3 -2 and HCO 3 -1 )and strong acidic anions (Cl -1 and SO 4 -2 )expressed as percentage is plotted on the y axis

Sodium Adsorption Ratio (SAR)
It is a measure of the suitability of water for use in agriculture and given by the relation: Based on SAR values water samples are classified as excellent (SAR<10), good (10-20), doubtful (20-30) and unsuitable (>30).The SAR value is associated with alkalinity hazard in ground water used for irrigation.In the present study of ground water samples SAR value varied from 5.85 to 13.83.

Residual Sodium carbonate (RSC)
The hazardous effects of carbonate and bicarbonate in ground water used for irrigation are best explained in terms of residual sodium carbonate (RSC) which is calculated as follows Based on RSC water has been classified as safe (RSC<1.25),marginal (RSC=1.25-2.50)and unsuitable (RSC>2.50).In the present study of ground water samples RSC value varied from -5.85 to 1.48.

Magnesium Ratio
The quality of water is greatly affected by magnesium, because large amount of magnesium in water makes the soil alkaline which leads to a decrease in crop yield.The amount of magnesium in water is best expressed as the magnesium ratio which is calculated as follows Water has been classified as good (Mg ratio<20), suitable (Mg ratio=20-50) and poisonous (Mg ratio>50) for plants.In the present study of ground water samples RSC value varied from 27.3 to 47.7.

Permeability Index (PI)
Permeability index (PI) is used to measure the suitability of ground water for irrigation purpose.With the consistent use of water the levels of sodium potassium magnesium and bicarbonates change in the soil so that permeability index changes.Permeability index is given by the equation Based on PI water has been classified as good (Mg ratio<20), suitable (Mg ratio=20-50) and poisonous (Mg ratio>50) for plants.In the present study RSC value varied from 27.3 to 47.7.

USSL classification
For the use of water in irrigation purpose it useful to interpret the water quality by USSL diagram which tells us about the alkali hazard of the groundwater samples for the study area.(Todd  1980).In this diagram the sodium adsorption ratio is plotted against specific conductance.The sixteen classes in the diagram indicate the extent that waters can affect the soil in terms of salinity hazard as low(C1),Medium(C2), high(C3), and very high(C4)and similarly sodium hazard as low(S1), medium(S2), High(S3) and very high(S4).Most of the sample of the analyzed data fall in the region C3S4.This category is predominant in the study area and it is suit-able for irrigations purposes as shown in Fig. 5.

Physicochemical Characteristics
The assessment of Physicochemical characteristic of ground water is carried out on site using the water testing kit.The value of various parameters collected from the study area is presented in Table 2 pH measurements The pH of groundwater in the study area varied from 7.1 to 9.2, indicating its alkaline nature.(WHO limit 6.5 to 8.5; WHO 1993), only two samples exceed the limit of 8.5.

Electrical Conductivity (EC)
Conductivity of the groundwater in the study area varied from 554 to 3212 µS/cm.(WHO limit 1500 µS/cm ; WHO 1993).Measurement of conductivity is important as it provides an insight to concentrations and type of ions present in ground water.A high conduction is generally an indication of high chloride ion concentration in ground water.Water is regarded as excellent (conductivity less than 500 µS/cm), good (500-1250 µS/cm), permissible (1250-2500 µS/cm), bad (2500-5000 µS/cm) and unsuitable for irrigation (above 5000 µS/cm).

Total dissolved solids (TdS)
Cations including (Na + , K + , Ca +2 and Mg +2 ) and anions including (HCO ) are the major contributors toward TDS .The TDS of ground water in the study area varies from 256 to 1096 mg/l.Water is regarded as excellent with TDS less than 150 ppm, with 150-400 good, with 400-1500 permissible and above 1500 ppm it becomes unsuitable for irrigation.

dissolved Oxygen (dO)
DO content varied from a minimum value of 2.3 mg/l to 3.g mg/l.It showed a typical relationship with temperature as the temperature rises the DO content falls.

Heavy metal ion
The ground water samples were also analyzed for metal concentrations (Tables 3) it was found that the metal ion concentration was well within the safer limits as given by WHO.The recommendation for safe limits of metal ions in drinking water is given in Table 4 .Maximum arsenic concentration was found in Patti town (0.005mg/l) and it varied from 0.001 mg/l to 0.005 mg/l in the entire study area.These values of As are well within the permissible limits recommended by USEPA 32 .Hence the water of the study area is suitable for human consumption and domestic usage.

1.
The type of water that predominates in the study area is Ca-Mg-HCO 3 type during based on hydro-chemical analysis.

2.
The suitability of water for irrigation is determined based on SAR, %Na, RSC and salinity hazard, it is only an empirical conclusion.Other factors like soil type, type of crop, frequency and pattern of crop, rain fall and its frequency, climate, etc. all are important in deciding the suitability of water.Most of the samples in the study area fall in the suitable range for irrigation purpose either from SAR, % Na or RSC values.

3.
Physicochemical characteristic of water were determined in order to assess the overall quality of water.

4.
The concentrations of heavy metal ions in water samples were well below the permissible limits indicating their suitability for drinking and irrigation purposes 5.
The correlation coefficient values for the water samples show a perfect positive correlation 6.
Most of the samples in study area fall in the suitable range for irrigation and drinking purpose as recommended by WHO 2011.

Fig. 2 :
Fig. 2: variation and correlations of various ions in water samples