Variation in Groundwater Quality with Seasonal Fluctuation in Jharia Coal Mine Region, Jharkhand, India

aBSTRaCT Jharia coal mining areas is one of the most important coal mining area in India. It is roughly elliptical or sickles – shaped, located in Dhanbad district of Jharkhand. For the assessment of groundwater quality, Twenty Nine groundwater samples were collected from Jharia coalfield. The pH of the analysed water samples is slightly acidic to slightly alkaline in nature in both the season. In majority of the samples, the analyzed parameters are well within the desirable limits and water is potable for drinking purposes. However, concentrations of EC, TDS, TH, SO 4 2-, Na + , Ca 2+ and Mg 2+ exceed the desirable limit at few sites. The water level fluctuation shows in the study area for year 2013 is 1.29 to 6.9 mbgl. West and some part of the northern area are facing extreme scarcity due to lower availability of groundwater resource. However, eastern region of the study area has sufficiently available of groundwater resources in the Jharia coalfield. This study is useful for utilization of groundwater resources in mining area and helps in future water resource planning for the area.


InTRoduCTIon
Water is an essential and vital component for our life-support system.Rapidly deleting of groundwater supplies as a consequence of continued population growth and industrialization threaten the quality of many aquifers in India.For evaluating the suitability of groundwater for different purpose, understanding the chemical composition of groundwater is necessary.Further, it is possible to understand the change in quality due to rock-water interaction (weathering) or any type of anthropogenic influence (Todd 1980, Kelly 1940).The definition of water quality is much depending on the desired use of water.Therefore different uses require different criteria of water quality as well as standard method for reporting and comparing result of water analysis (Babiker 2007).Access to safe drinking water remains an urgent necessity, as 30 % of urban and 90 % of the rural Indian population still depends completely on untreated surface or groundwater resources (Kumar et al. 2005).Scarcity of clean and potable drinking water has emerged in recent years as one of the most serious developmental issues in many parts of West Bengal, Jharkhand, Orissa, Western Uttar Pradesh, Andhra Pradesh, Rajasthan and Punjab (Tiwari & Singh 2014) Tiwari et al. 2014).The objective of this study is to assess groundwater quality with reference to seasonal fluctuation and primarily investigation; an attempt has been made to assess its suitability for drinking and domestic uses and also evaluate of availability of groundwater resources of the area.

Study area
Jharia coal mining area is one of the most important Coal mining area in India.It is roughly elliptical or sickles -shaped, located in Dhanbad district of Jharkhand lies between latitude 23 o 39 / N and 23 o 48 / N and longitudes 86 o 11 / E and 86 o 27 / E. It stretches from Chandanpura on the west to Sindri on the east.The main component of the natural drainage in Jharia coalfield (JCF) is the Damodar River.There are eight major streams, a few perennials and the rest intermittent, which drains the JCF from north to south to join the Damodar River.They are Tisra, Chatkari, Katri, Khudia, Jamuniya, Kumari and Bansjora etc.The climate in the Jharia coal mining area is very pleasant during cold weather months starting from November to February.The occasional rain during the hot weather from March to June makes the climate, but from June to October the conditions are not on the whole very unpleasant during October to November.The general climate may broadly be described as the of the tropical monsoon belt.The annual rainfall in Jharia and adjacent region varies from 1197 mm to 1382 mm.This is the most exploited coal mining area because of available metallurgical grade coal reserves.The temperature range in coal filed area varies between 5°C and 48 °C.

Sample collection and preservation
A systematic sampling was carried for the assessment of groundwater quality of Jharia coal mining area.Representative 29 groundwater samples were collected from different mines of Lodna, Bastacolla, Sijua, Western Jharia, Block-II, Barora etc of the study area (Fig 1).The groundwater samples were collected in one litre narrow-mouth pre-washed polyethylene bottles.Prior to each field work polyethylene bottles were washed in the laboratory with dilute hydrochloric acid and then rinsed twice with double distilled water.Suspended sediments were separated from the water samples in the laboratory by using 0.45 µm Millipore membrane filters.The water samples were analyzed for various-Physico-chemical parameters.The sampling and analysis was made following standard method (APHA, 1998).

Rainfall and water table characteristics
Study area receives more rainfall due to coal dust, which attracts clouds and brings rainfall to the area.Rainfall is the principal method of recharge to groundwater.Southwest monsoon brings rainfall to this area during the months of June to October mainly.The annual average rainfall pattern from the year 2000 to 2013 has been assessed (Fig 2).The maximum rainfall 2311mm and the minimum rainfall is 921mm.

Comparative analysis of wlF using GIS
In comparative analysis, depth to water level data of 29 monitoring wells located in the study area for pre and post-monsoon in the year 2013.Pre-monsoon data of depth to water level had been collected in the month of June and the post monsoon data of depth to water level had been collected in the month of December (Table 1).Data is plotted on thematic contour map it can observed the trend of depth to water level in unconfined aquifers.
From the contour map it can be observed that the maximum depth to water level shown by wells in the pre-monsoon is 3.05 to 11.10 mbgl (Fig 3) and minimum in post-monsoon it shows 1.4 to 7.5 mbgl (Fig. 4) in year 2013.The water level fluctuation shows in the year 2013 is 1.29 to 6.9 mbgl (Fig 5).There are six blocks in the Jharia coal field such as Londna, Bastacolla, Kuskunda.BlockII, Barora and western Jharia.The maximum water level fluctuation shows in Bastocalla area and Londna area due to some lithological features which affect groundwater fluctuation.The good recharge of groundwater shows in the eastern Jharia area, which shows less groundwater fluctuation.The Damodar River is the main sources of recharge of the groundwater in the study area.The groundwater is recharged through by cracks, fissure and planes discontinuity.Thus, from above studies, we found that west and some part of the northern part are facing extreme scarcity due to lower availability of groundwater and eastern region of the study area has sufficiently available of groundwater resources.

Major ion chemistry
Among major cations for Post-monsoon, calcium was the dominant ions representing on average 46% of total cations.Magnesium and sodium ions were of secondary importance, representing on average 26% and 23% of total cations, respectively.Potassium was least dominant cation and representing 5% of the total cations (Figure 6).The order of cation for post-monsoon abundance was Ca 2+ > Mg 2+ > Na + >K + .However, in pre-monsoon season calcium was the dominant ions representing on average 39% of total cations.Sodium and magnesium ions were of secondary importance, representing on average 29% and 26% of total cations, respectively.Potassium was least dominant cation and representing 6% of the total cations (Figure 7).The order of cation abundance was Ca 2+ > Na + >Mg 2+ >K + in pre-monsoon season.Among the major anions, bicarbonate was generally dominant and representing on average 43% of the total anions.Sulphate is the second dominant anion, representing on an average 39% of the total anions.Chlorides were less dominant ions and contributing Fig. 5: depth to water level fluctuation period 2013 17% to the total anions respectively (Figure 8).Nitrate and fluoride are the least dominant anion of the total anions.The order of anions for postmonsoon abundance in the groudwater was found as HCO 3 -> SO 4 2-> Cl ->NO 3 ->F - .However, in premonsoon season bicarbonate is the dominant anion, representing on an average 43% of the total anions.Sulphate is the second dominant anion, representing on an average 37% of the total anions.Chlorides were less dominant ions and contributing 18% to the total anions respectively.Nitrate and fluoride is the least dominant anion of the total anions.The order of anions abundance in the groudwater was found as HCO 3 9).

Suitability of groundwater for drinking and domestic purposes
The physico-chemical parameters of the analytical results of groundwater were compared with the standard guideline values recommended by the World Health Organization (WHO, 1997) and Bureau of Indian Standards (BIS, 2003) for drinking and public health standards (Table 2).The pH of the groundwater samples were found to be ranging from 6.5 to 8.2 and with mean of 7.2 for post-monsoon season, while the pre-monsoon season water samples range 6.5 to 8.3 and mean 7.3.The water samples indicate is slightly acidic to alkaline in nature.The overall conductivity ranges from 480 µS/cm to 1300 µS/cm and mean 862.3 for post -monsoon season, while the pre-monsoon season water samples range 630 µS/cm to 1590 µS/cm in groundwater of study area.The TDS were varied from 350 mg/L to 1150 mg/L for postmonsoon season while the pre-monsoon season water samples 532 mg/L to 1377 mg/L.The values of TDS exceed the desirable limit of 500 mg L -1 in 96 % samples of groundwater in post-monsoon, while 100% in pre-monsoon season.The total hardness (TH) of the analyzed water samples of the study area varies between 210 mg/L to 752 mg/L and (Avg.444 mg/L) in post-monsoon.However, pre-monsoon season water samples it varied 294 mg/L to 917 mg/L and (Avg.546 mg/L) respectively indicating hard to very hard types of water.The chloride content in the study area varied from 39 mg/L to 198 mg/L in the groundwater in post -monsoon season.However, the pre-monsoon season water  Concentration of F -is within recommended limit of 1.5 mg L -1 in groundwater samples in post-monsoon season.However, in pre-monsoon season, values of F -exceed the permissible limit of 1.5 mg L -1 in 21% samples of groundwater.The range of calcium ions was 28 mg/L to 192 mg/L for post monsoon

Fig. 1 :
Fig. 1: Sampling sites in the study area

Table 1 : water table fluctuation of Jharia coalfield
(Berner and Berner 1987)00 mg L -1 in 45 % samples of groundwater in post-monsoon, while 51% in pre-monsoon season.Higher concentration of sulphate may be attributed to rock weathering or anthropogenic sources like industrial and agricultural effluents(Berner and Berner 1987).Higher F - concentration causes dental and skeletal fluorosis such as mottling of teeth, deformation of ligaments and bending of spinal cord(Tiwari and Singh 2014).