Hydrological characterization and assessment of

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that have considerable impact on surface and groundwater system of the territory. The .... The surface water level along the drain from Dhansa to Kakraula. 103.
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Final copy of the author submitted version to the journal for the article given below (only for archiving): “Shekhar Shashank and Sarkar Aditya. 2013. Hydrogeological characterization and assessment of groundwater quality in shallow aquifers in vicinity of Najafgarh drain of NCT Delhi. J. Earth Syst. Sci. 122 (1):43–54. Paper available on the website: http://www.ias.ac.in/jess/feb2013/43.pdf Springer publication link: http://link.springer.com/article/10.1007%2Fs12040-012-0256-9#page-1

Hydrogeological characterization and assessment of groundwater quality in shallow aquifers in vicinity of Najafgarh drain of NCT Delhi. Shashank Shekhar* and Aditya Sarkar* * Department of Geology, University of Delhi, Delhi-110007. Corresponding author email: [email protected]

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Najafgarh drain is the biggest drain of Delhi and contributes about 60% of the total

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wastewater that gets discharged from Delhi in to river Yamuna. The drain traverses a

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length of 51 kilometers before joining river Yamuna, and is unlined for about 31

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kilometers along its initial stretch. In recent time, efforts have been made for limited

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withdrawal of groundwater from shallow aquifers in close vicinity of Najafgarh drain

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coupled with artificial recharge to groundwater. In this perspective, assessment of

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groundwater quality in shallow aquifers in vicinity of the Najafgarh drain of Delhi and

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hydrogeological characterization of adjacent areas was done. The groundwater quality

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was examined in perspective of Indian as well as World Health Organization’s drinking

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water standards. The spatial variation in groundwater quality was studied. The linkages

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between trace element occurrence and hydro chemical facies variation were also

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established. The shallow groundwater along Najafgarh drain is contaminated in

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stretches and the area is not suitable for large-scale groundwater development for

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drinking water purposes.

Abstract

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Keywords: Delhi; Najafgarh drain; contamination; groundwater salinity; hydro chemical

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facies; correlation matrix.

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1. Introduction

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The National Capital Territory (NCT) of Delhi (Fig.1) is one of the most fast growing

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metropolitan cities in the world. It faces a massive problem of voluminous generation of

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wastewater. This wastewater is mainly contributed from numerous drains of NCT Delhi

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that have considerable impact on surface and groundwater system of the territory. The

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effect on surface water is visible from river Yamuna where upstream of Wazirabad, the

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color of river water is bluish green which changes to dark grey downstream of

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Wazirabad, from where the Najafgarh drain joins river Yamuna (Fig.1). Henceforth, a

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series of 19 drains join river Yamuna, making it a giant drain. The impact of this

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wastewater on the groundwater system is even more profound. There is considerable

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contamination of groundwater by industrial and domestic effluents mostly carried

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through various drains (Singh 1999).

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The Najafgarh drain is the biggest drain of NCT Delhi, discharging 287.5 Million Liters

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per Day (MLD) (0.2875 Million m3/day) wastewater in to river Yamuna (NEERI

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2002).The Najafgarh drain contributes about 60 % of the total wastewater that gets

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discharged from Delhi in to river Yamuna (Kumar et al 2006).

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INSERT Fig.1.

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The Najafgarh drain enters Delhi from Haryana from south-west corner of Delhi. It

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transverses a length of 51 kilometers before joining the river Yamuna (INTACH 2003).

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In its initial stage through south-west district of NCT Delhi, the drain carries flood

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waters, wastewaters from Haryana and surface runoff from the adjoining catchment.

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Out of the 51 kilometers stretch of the drain, nearly 31 kilometers stretch of the drain

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passes through south-west district from near Dhansa to Kakraula (Jindal 1975) (Fig.1).

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Thus, nearly 60% length of the Najafgarh drain flows through south-west district of NCT

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Delhi and all this stretch of the drain is unlined. Moreover from Dhansa to Kakraula

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(Fig.1) very few (may be 2-3 drains) subsidiary drains join this big drain and

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subsequently after Kakraula nearly 38 big and small drains (Fig.2) joins Najafgarh drain

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(WAPCOS 1999). Thus, apparently (on visual observation) the quality of water flowing

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through the drain is better in the stretch from Dhansa to Kakraula (Fig.1). There were

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proposals (Bajpai 2011, INTACH 2003, Shekhar 2006) suggesting limited groundwater

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withdrawal coupled with artificial recharge in this stretch of aquifer along Najafgarh drain

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from Dhansa to Kakraula. However, it was also argued that unlined drains in recharge

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areas act as a source of pollution to groundwater (Kumar et al 2006). In this

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perspective, it becomes important to have an assessment of groundwater quality in

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shallow aquifers in vicinity of the Najafgarh drain.

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INSERT Fig.2.

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2. Hydrogeology of the study area

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The Najafgarh drain traverses through south-west, west, north-west and north district of

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NCT Delhi (Fig.1). The stretch of the drain through south-west and west district is

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unlined while stretch of the drain through north-west and west district is lined. The

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borehole data and geophysical study reveals that subsurface formation along the area

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closely adjacent to drain has alternate fluvial and aeolian bands distributed sporadically.

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The alluvial deposits are Pleistocene in age with inter-bedded, lenticular and inter-

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fringing deposits of silty sand, clay and kankar. The proportion of finer sediment is more.

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Goel (1990) in sieve analysis of borehole sediments from Dhulsiras (Fig.1) revealed that

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in depth range of 0 to 45 meters below ground level (mgbl), nearly 60% is finer sand

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composition and rest is mixture of silt and clay. INTACH (2003) reported average rate of

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infiltration at the bed of the Najafgarh drain in south-west district of Delhi as 0.21

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mm/hour. They (INTACH 2003) mention permeability of the subsurface formations

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below and adjacent to the Najafgarh drain in the stretch of the drain from Dhansa to

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Kakraula (Fig.1) as ranging from 3 to 6 m/day to 28.11 m/day and transmissivity of the

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formation as ranging from 63.05 m2/day to 927.7 m2/day.

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Throughout south-west district and major part of west district, the depth to bedrock

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below Najafgarh drain and its adjacent area is in the range of 200-300 meters below

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ground level (mbgl) (Shekhar 2004). As the drain in its later part takes a bend from N-S

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orientation to nearly E-W and flows eastward to join river Yamuna, it is gradually moving

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towards surface exposure of hard rocks (CGWB 2006), (Fig.3). Thus, thickness of the

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non-indurated aquifers that are more prone to contamination decreases towards later

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part of the drain.

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INSERT Fig.3.

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The Najafgarh drain and its tributaries show the effect of recharge from the water being

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carried by drain and it is evident in the form of greater depth to fresh /saline interface in

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groundwater (Shekhar et al 2005). Shekhar et al (2005) and Shekhar (2006) envisaged

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of an elongated fresh groundwater lens along Najafgarh drain in south-west district

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stretch of the drain. The salinity of groundwater increases as depth increases. The

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shallower groundwater all along Najafgarh drain and its close vicinity has lower salinity.

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The fresh groundwater aquifer thickness along Najafgarh drain is more in unlined

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section of the drain. The surface water level along the drain from Dhansa to Kakraula

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(Fig.1) is such that there is some depth of water in the drain throughout its length even

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when there is no flow. This situation helps in recharging groundwater in favourable

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conditions (When water table is below the water level in the drains). Bajpai (2011)

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established through remote sensing study that the Najafgarh drain and its tributaries in

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its initial stretch through south-west district of Delhi (Fig.1) flows through a naturally

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defined valley setting. Thus, the hydrogeological equilibrium of the water in the drain

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and the adjacent aquifer in its initial stretch is similar to stream aquifer interaction.

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Shekhar et al (2006) mentioned that in aquifers adjacent to the Najafgarh drain, there

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are isolated patches showing concentration of fluoride beyond permissible limit. Since

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groundwater in the fluoride-affected areas have higher salinity, it is possible that the

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high level of fluoride is due to localized effects of natural sources.

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2.1 Depth to water level in the study area:

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A regional depth to water level map (Fig.4) including areas much beyond close vicinity

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of Najafgarh drain was prepared to have an insight in to regional and local variations in

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depth to water level of the area. The depth to water level in the areas closely adjacent to

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the drain varies in the range of 3 to 16 meters below ground level (mbgl) (Fig.4). The

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shallower depth to water level is noticed in initial part of the drain where it enters Delhi

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and in later part of the drain where it meets river Yamuna. The relatively deeper water

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levels are found in middle stretch of the drain. In areas to right in downstream of the

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drain, depth to water level increases as one moves in south-east direction and reaches

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to maximum of 65 mbgl, some kilometers ahead (these areas are adjacent to the hard

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rocks). Shekhar et al (2009) also mentions about deeper depth to water level in the

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range of 40-60 mgbl in these areas of Delhi shown in Fig.4. In areas to left of the drain,

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relatively shallower depth to water level is found, reaching to maximum of 20 mbgl in

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Najafgarh and Ojwah areas (Fig.4). The groundwater in areas with relatively shallower

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depth to water level is more vulnerable to anthropogenic contamination.

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INSERT Fig.4.

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2.2 Water table elevation in the study area:

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A regional water table elevation map (Fig.5) including areas much beyond close vicinity

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of Najafgarh drain was prepared to have an insight in to regional and local variations in

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water table elevation of the area. The water table elevation in areas adjacent to

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Najafgarh drain is found in the range of 197 to 206 meters above mean sea level

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(mamsl) (Fig.5). The higher water table elevation is noticed in initial part of the drain

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where it enters Delhi and in later part of the drain (later half segment of the drain before

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it joins river Yamuna). The lower water table elevations are found in the N-S stretch of

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the drain (Fig.5). The regional water trough near to Ojwah defined by 194 mamsl

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contour has a tremendous influence on groundwater flow to the extent that in first half

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stretch of the Najafgarh drain, groundwater flow from areas adjacent to the drain and

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others converge towards it. Thus in this stretch of the drain on left side areas

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groundwater flow seems to be away from the drain, while on right side of the drain

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groundwater flow is towards the drain (Fig.5). In later half stretch of Najafgarh drain

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apparently on left side of the drain groundwater flow is towards the drain. While in areas

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on right side in downstream of the drain in some stretches there seems to be apparently

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not much of groundwater flow and in some areas / stretches groundwater seems to be

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flowing away from the drain (Fig.5). In areas where groundwater flow is away from the

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drain, there is possibility that the contaminants entering the groundwater system are

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transported to relatively greater distance by advection along with the groundwater flow

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direction. The above-mentioned hydrogeological characteristics of the area (depth to

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water level, water table elevation, aquifer parameters, aquifer material, infiltration rates

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etc.) hints at dynamic interaction between the water flowing through the drain and

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groundwater, thereby affecting the quality of groundwater.

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INSERT Fig.5.

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3. Methodology for assessment of groundwater quality:

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The approach to assessment of groundwater quality in shallow aquifers in vicinity of

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Najafgarh drain of NCT Delhi involved groundwater sampling at evenly distributed

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locations all along the drain. The sampling was done mainly during pre monsoon period

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in the month of May from hand pumps in the areas adjacent to the drain.

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Acid treated samples were collected for trace element/ heavy metal analysis and normal

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samples for major element analysis. The samples were analyzed at Central Ground

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Water Board (CGWB) chemical laboratory at Chandigarh using Atomic Absorption

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Spectroscopy (AAS), Ion chromatography and volumetric titration techniques (Shekhar

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2008). The sampling locations varied from sites located approximately at a distance of

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3-600 meters from the drain (Fig.6). It was observed subsequently during analysis that

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the samples, which were relatively away from the drain, had lesser amount of

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anthropogenic contaminants. The variations in concentration of the chemical

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components were studied in the perspective of permissible limit of drinking water

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following Bureau of Indian standards (BIS 1991) and World Health Organization

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standards (WHO 2011). The variation in chemical constituents in groundwater was also

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studied to observe the pattern of similarity/dissimilarity in various chemical constituents

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in space, and to account for the observed patterns. The study of hydro chemical facies

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of the groundwater was done with help of Hill-Piper’s trilinear plot. The Hill-Piper trilinear

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plot was prepared for twenty one groundwater samples where all the necessary data for

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hydrochemical facies classification was present. AquaChem software was used for

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creating multiple parameter plot (Hill- Piper trilinear plot) and correlation Matrices

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(Sarkar 2011). INSERT Fig.6.

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4. Results:

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In perspective of BIS standards for drinking water (1991), 88% of the groundwater

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samples collected showed concentration of iron beyond permissible limit prescribed for

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drinking water of 1 mg/liter (BIS 1991) and 23% of groundwater samples collected

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showed concentration of manganese beyond their prescribed permissible limit for

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drinking water of 0.3 mg/liter(BIS 1991). It must be mentioned that WHO (2011) gives

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no specific guidelines for permissible limit of iron and manganese in drinking water. In

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about 42% samples, concentration of nitrate exceeded the pemissible limt prescribed

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for drinking water of 45 mg/liter (BIS 1991), while in perspective of WHO (2011)

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standards about 35% samples had concentration of nitrate beyond the pemissible limt

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prescribed for drinking water of 50 mg/liter.

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permissible limit for drinking water of 0.01 mg/liter (BIS 1991), (WHO 2011) in about

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3% samples. Cadmium exceeded their prescribed permissible limit for drinking water of

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0.01 mg/liter (BIS 1991) in about 3% samples, while in perspective of the WHO (2011)

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Arsenic exceeded their prescribed

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prescribed permissible limit for drinking water it exceeded the limit of 0.003 mg/liter in

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about 69% samples. As per WHO (2011) guidelines chromium exceeded the prescribed

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permissible limit for drinking water of 0.05 mg/liter in about 12% of the samples, while in

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perspective of BIS (1991) prescribed permissible limit for drinking water, all the samples

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were well within the prescribed permissible limit of 0.1mg/liter. In about 69% samples

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lead exceeded the prescribed permissible limit for drinking water of 0.01 mg/liter as per

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WHO (2011) guidelines, while in perspective of BIS (1991) standards for drinking water,

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about 19% samples had lead concentration in groundwater above the prescribed

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permissible limit of 0.05mg/liter. The groundwater quality database used in the study is

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attached as supplementary material with the paper (Appendix-A).

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The concentration of chemical constituents such as chromium, copper, lead and

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cadmium in groundwater when plotted with respect to the sampling location showed

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roughly cyclic behavior (Fig.7). Similar patterns were observed for concentration versus

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sampling location plots for iron and manganese (Fig.8). The spatial variation in above-

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mentioned chemical constituents in the groundwater samples was prominent. These

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cyclic patterns may be on account of numerous subsidiary drains joining Najafgarh

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drain, accelerating the anthropogenic enrichment in groundwater. However, such trends

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were not observed for other constituents like arsenic, nickel, magnesium and fluoride

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due to their absence in samples or unavailable data from some locations.

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INSERT Fig.7.

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INSERT Fig.8.

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These plots are useful in assessing spatial variation in concentration of different

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groundwater contaminants but they are not enough to relate the similarity/dissimilarity

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among chemical contaminants. Hence, a correlation coefficient matrix was prepared for

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twenty one out of twenty six sampling locations which provided sufficient informations

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for all analyzed chemical constituents (Table-1).

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The high correlation coefficient value of electrical conductivity with chloride pointed to

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the fact that salinity could be mainly chloride controlled. The higher salinity in

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groundwater is attributed to longer retention time of groundwater and lack of flushing in

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general and in very shallow water level area, repeated oxidation and evaporation may

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have lead to salinity enrichment in groundwater.

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INSERT TABLE-1

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The significant positive correlation coefficient value between nitrate and sodium, nitrate

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and potassium, nitrate and magnesium and nitrate and chloride established

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degrardation in groundwater quality due to infiltration of wastewater from Najafgarh

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drain. The inference in further authenticated by relatively high correlation coefficient

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value between chloride and sulphate.The significant positive correlation coefficient

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value between fluoride and bicarbonate coupled with high level of fluoride in a few

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locations (see Appendix-A) suggests contamination of the groundwater at a few location

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by excess use of fertilizers.

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In most sampling locations Nickel was absent in groundwater. However in places

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where traces of Nickel was found , it showed good correlation with Iron (Fe), chromium

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(Cr) and Zinc (Zn). It is possible that the trace heavy metals in groundwater were

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introduced as anthropogenic contamination from industrial wastes of metal processing

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industries present in the catchment of Najafgarh drain system.

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Moturi et al (2004) established that the solid wastes from industrial belt of Delhi

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had high mean level of toxic metals and opined that these toxic metals are produced by

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small scale metal processing industries. Baneerjee ADK (2003) analyzed dust samples

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from some of the industrial areas in Najafgarh drain catchment and concluded that

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these samples had high concentration of heavy metals like chromium, copper and nickel

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which are linked to industrial sources.

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Manganese showed significant positive correlation coefficient value with arsenic

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indicating a common source for both of them. In about 23% samples manganese

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concentration in groundwater was beyond precribed limit for drinking water of 0.3

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mg/liter (BIS 1991). Since it has been established that high concentration of heavy

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metals are linked to industrial sources, it is possible that higher concentration of

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manganese in groundwater is also contributed by industrial wastes. It is suggested that

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the geogenic inputs of manganese in groundwater system was further enhanced by

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anthropogenic sources. Since arsenic correlated well with manganes its concentration

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in groundwater could be linked to anthropogenic sources. Lalwani et al (2004) had

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similar observation and opined that the arsenic contamination in groundwater of Delhi

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could be from the arsenic present in garbage of open landfill sites rich in chemicals.

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Dubey et al (2012) confirmed anthropogenic source for arsenic contamination in

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groundwater of Delhi.

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The correlation matrix could be an effective tool to understand the relationship

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among different major physiochemical parameters and trace elements but hydro

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chemical facies could be further used to assess the nature and portability of

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groundwater. The Hill-Piper plot is one of the premier graphical plots for delineating

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hydro chemical facies. The Hill-Piper plot was prepared for the twenty-one samples,

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which provided sufficient information. The plot (Fig.9) revealed that the major water

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facies types in the studied locations were Na-Mg-Cl-HCO3 type, Na-Mg-HCO3-Cl type,

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Na-Cl-HCO3 type, Na-HCO3-Cl type, Na-Mg-Ca-HCO3-Cl type, Na-K-Cl-SO4 type and

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Mg-Na-Ca-Cl-HCO3 type (Sarkar 2011). It becomes clear from the trilinear plot (Fig.9)

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that the dominant cation in the hydrochemical facies are prominently sodium with

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magnesium, while the anions vary mainly from chloride to bicarbonate end of the plot.

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As mentioned earlier the bicarbonate ions showed good correlation with Nickel and

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sulphate ions showed good correlation with Nitrate, while chloride ions does not show

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prominent correlation with any trace element and moderate correlation with nitrate. In

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this context it can be inferred that originally the groundwater facies in the area was

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chloride type, the process of dilution by influx of drain water in to groundwater system

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could have lead to the changes in the groundwater facies originally from chloride type

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towards bicarbonate type. Thus it can be said that the anthropogenic contamination of

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groundwater system by the drain water and the trace element in the drain water

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simultaneously changed the groundwater facies. INSERT Fig.9

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5. Discussions

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The hydrogeological characteristics of the catchment of Najafgarh drain system and

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aquifer parameters of formation along Najafgarh drain establishes vulnerability of

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groundwater to contamination by wastewater flowing through the drain. It has also been

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indicated by isotopic study (Datta et al 1996) that there is seepage recharge from

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surface water courses in Delhi. In case of Najafgarh drain, mixing of seepage recharge

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from the drain with water coming from adjacent highlands have been reported (Kumar et

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al 2011).

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The Najafgarh drain water was reported to have considerable concentration of

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heavy metal contaminants like iron, lead, manganese, copper and nickel (Sharma et al

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2009). Hence, it is quite possible that along with seepage recharge from the drain, the

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heavy metals contaminated the groundwater as well. However, a recent study by

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Lorenzen et al (2011), based on bank filtration technique, proposed groundwater

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extraction from the aquifer near to the drain for drinking purposes. The shallow aquifer

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in this area is contaminated in different stretches. Thus, any groundwater development

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for emergency requirement should be preceded by micro level groundwater quality

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study. The groundwater pumping in such areas must be staggered in space and time to

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control saline water up coning (Rao et al 2006, 2007).

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A system simulation and numerical modeling study can suggest optimal pumping

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from the aquifer under different possible scenarios. The model can incorporate

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possibilities of contaminant transport from sampling locations where contaminants have

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been reported. It is also suggested that the sewage treatment level can be estimated so

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that the drain bank filtrated water in to aquifer attains portable drinking water standards.

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This can be enforced on the concerned authorities undertaking work of sewage

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treatment projects along the drain.

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6. Conclusions

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The study gives a detailed insight in to hydrogeology of the area adjacent to Najafgarh

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drain and groundwater quality in shallow aquifers along the Najafgarh drain. It

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establishes contamination of groundwater system in vulnerable stretches by wastewater

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flowing through the drain. It has been established that originally the groundwater in the

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aquifers had evolved to chloride facies, where the total dissolved solutes in groundwater

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was contributed mainly by geogenic sources. The groundwater recharge to shallow

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aquifers along the drain caused dilution of the chloride facies water leading to re

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evolution of the groundwater facies towards bicarbonate type. In this process, the

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groundwater quality was degraded by anthropogenic contaminants from wastewater

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flowing through the drain. Thus, recharge through drain water lead to influx of trace

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element / heavy metals in groundwater. This establishes the fact that anthropogenic

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contamination of the groundwater simultaneously leads to changes in the hydro

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chemical facies of the groundwater. The influx of contaminants in to groundwater

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system through network of subsidiary drains is also evident from the pattern of spatial

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variation in concentration of the groundwater contaminants. Hence, study on

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anthropogenic contamination of groundwater system should be coupled with hydro

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chemical facies analysis for comprehensive assessment of groundwater quality.

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Acknowledgements

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It is duly acknowledged that the groundwater sampling was done by the first author

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when he was working as a Scientist at Central Ground Water Board and the samples

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were analyzed at CGWB laboratory, Chandigarh. The data for publication was taken

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from CGWB Report Shekhar (2008). The authors are grateful to anonymous reviewers

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for their meticulous review of the manuscript, which helped in improving the manuscript.

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Shekhar S, Mohiddin S K and Singh P N 2006 Variation in concentration of fluoride in the groundwater of South-west District, NCT Delhi- A Case Study, In Assessment of groundwater Resources and Management, ed. A L Ramanathan, P Bhattacharya, A K Keshari, J Bundschuh, D Chandrashekharan and S K Singh, I K International, New Delhi, 370-376. Shekhar S 2008 Integrated groundwater management study in New Delhi, Central, West, North-east, East and South districts, NCT Delhi with special reference to surface water-groundwater interaction along the Najafgarh drain, Report Central Ground Water Board, Ministry of water resources, Delhi Shekhar S, Purohit R, Kaushik Y B 2009 Groundwater management in NCT Delhi, Technical paper included in the special session on Groundwater in the 5th Asian Regional Conference of INCID, December 9-11, 2009 held at Vigyan Bhawan, New Delhi, available online at http://www.cgwb.gov.in/documents/papers/INCID.html Singh R B 1999 Impacts of Urban Growth on Surface Water and Groundwater Quality (Proceedings of IUGG 99 Symposium HS5, Birmingham, July 1999). IAHS 259 227-231 WAPCOS 1999 Prefeasibility study for construction of a parallel channel to intercept the flows from Nallas out falling in to river Yamuna between Wazirabad barrage and Okhla barrage, draft final pre feasibility report for Irrigation and Flood Control Department, Government of NCT Delhi, Report, Water and Power Consultancy Services (India) Limited, A Government of India Undertaking, 9, Community Centre, Saket, New Delhi17. WHO 2011 Guidelines for drinking water quality, 4th edition, World Health Organization. List of Tables: Table-1 Correlation matrix for the groundwater quality data. List of Figures: Fig.1. Delhi map with inset of India map, showing Najafgarh drain. Fig.2. Map showing drains joining Najafgarh drain: 1. Palam drain, 2. Bupania drain, 3. Pankha road drain, 4. Vikaspuri drain, 5. Nilothi drain, 6. Sayed Nangloi drain, 7. Keshopur drain, 8. Subhash Nagar drain, 9. Khyala drain, 10. Jawalaheri drain, 11. Raghubir Nagar drain, 12. Madipur drain, 13. Ring Road drain, 14. Basai Darapur drain, 15. Ramesh Nagar drain, 16. Moti Nagar drain, 17. Punjabi Bagh drain, 18. Jaidev Park drain, 19. Shakur Basti drain, 20. Tulsi Nagar drain, 21. Anand Nagar drain, 22. Kanhiya Nagar drain, 23. Daryai drain, 24. Rana Pratap Bagh drain, 25. Shakti Nagar drain, 26. Shakti Nagar drain-2, 27. Gur Mandi drain, 28. G.T.Road drain, 29. Kamala Nagar Drain, 30. Roop Nagar drain, 31. Vijay Nagar drain, 32. Hansraj drain, 33. Patel Chest

17

462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489

drain, 34. Mall road drain, 35. Mall road Drain-2, 36. Timarpur drain, 37. Power house drain, 38. Wazirabad drain, Fig.3. Depth to bedrock map in the study area. Fig.4: The depth to water level map in the study area. Fig.5: Water table elevation map of the study area. Fig.6: Map showing sampling locations of the study area. Fig 7: Line plots showing spatial variation in cadmium (Cd), lead (Pb), copper (Cu) and chromium (Cr) for 1: Rawta, 2: Shikarpur road, 3: Shikarpur-2, 4: Nanakheri, 5: Isapur Khera, 6: Dhulsiras, 7: Chhawla, 8: Kutub Vihar, 9: Dwarka Sec.19, 10: Dwarka Sec.-16 STP, 11: Dharampura, 12: Dwarka Sec.-16 J Flat, 13: Nand Vihar, 14: Ghasipura,15: Deep Enclave,16: Vikash Nagar,17:Ranhola,18:Nathan Vihar, 19:Chander Vihar, 20:Nihal Vihar, 21: Karampura, 22: Shashtri Nagar, 23: Roop Nagar, 24: Timarpur, 25:Nehru Vihar D-9, 26:Nehru Vihar C-280 groundwater sampling locations. Fig 8: Line plots showing spatial variation in Iron (Fe) and Manganese (Mn) for 1: Rawta, 2: Shikarpur road, 3: Shikarpur-2, 4Nanakheri, 5: Isapur Khera, 6: Dhulsiras, 7: Chhawla, 8: Kutub Vihar, 9: Dwarka Sec.19, 10: Dwarka Sec.-16 STP, 11: Dharampura, 12: Dwarka Sec.-16 J Flat, 13: Nand Vihar,14: Ghasipura,15: Deep Enclave,16: Vikash Nagar,17:Ranhola,18:Nathan Vihar,19:Chander Vihar, 20:Nihal Vihar, 21: Karampura, 22: Shashtri Nagar, 23: Roop Nagar, 24: Timarpur, 25:Nehru Vihar D-9, 26:Nehru Vihar C-280 groundwater sampling locations. Fig.9. Hill-piper plot for the groundwater quality data.

18

Appendix-A Table showing the location of sampling stations and the concentration of different chemical parameters. Cd-Cadmium, Cr-Chromium, Cu-Copper, Fe-Iron, Mn-Manganese, Ni-Nickel, Pb-Lead, Zn-Zinc, As-Arsenic, EC-Electrical Conductivity, ClChloride, SO 4 -Sulphate, NO 3 -Nitrate, F-Fluoride, Ca-Calcium, Mg-Magnesium, Na-Sodium, K-Potassium, HCO 3 -Bicarbonate, N.A – Not Analyzed/data not available S. No.

Locality

Cd

Cr

Cu

Fe

Mn

Ni

Pb

Zn

As

EC

Cl

SO 4

NO 3

F

Ca

Mg

Na

K

HCO 3

1.

Rawta

0.007

0.032

0.003

3.885

0.017

0.007

0.02

0.01

0

N.A

N.A

N.A

N.A

N.A

N.A

N.A

N.A.

N.A

N.A

2.

Shikarpur road

0.005

0.029

0.011

3.381

0.114

0

0.02

0.101

0

2250

489

125

75

2.23

21

88

410

10

467

3.

Shikarpur-2

0.009

0.041

0.017

1

0.076

0

0.014

0.032

0

N.A

N.A

N.A

N.A

N.A

N.A

N.A

N.A

N.A

N.A

4.

0.004

0.013

0.007

3.072

0.026

0

0.04

0.2

0

2780

774

95

55

0.84

83

121

390

3

317

5.

Nanakheri Isapur Khera

0.005

0.042

0.003

0

0

0

0.02

0.025

0

2340

300

50

48

1.47

13

45

510

6

995

6.

Dhulsiras

0.002

0.017

0.073

1.7

0.182

0

0.04

4

0

2120

511

230

8

0.3

79

82

315

4

249

7.

chhawla

0.009

0.046

0.003

1.7

0.045

0

0

1

0

N.A

N.A

N.A

N.A

N.A

N.A

N.A

N.A

N.A

N.A

8.

Kutub Vihar

0

0.025

0.005

2.3

0.096

0

0.04

0.133

0

N.A

N.A

N.A

N.A

N.A

N.A

N.A

N.A

N.A

N.A

0.003

0.046

0.001

2.259

0.029

0

0

0.11

0

1620

362

50

13

0.3

53

26

315

5

437

0.006

0.025

0

0.2

0.211

0

0.003

0.4

0

N.A

N.A

N.A

N.A

N.A

N.A

N.A

N.A

N.A

N.A

0

0.016

0.008

2

0.224

0

0

0.164

0

4980

1548

370

149

0.43

290

238

570

13

196

0.003

0.024

0.001

1.333

0.015

0

0

0.014

0

1100

223

105

10

0.5

53

52

135

6

234

9.

10. 11.

Dwarka Sec.19 Dwarka Sec.-16 STP

12.

Dharampura Dwarka Sec.-16 J Flat

13.

Nand Vihar

0.005

0.043

0.035

1.7

0.068

0

0.1

1.3

0

1180

113

50

9

1.2

41

32

175

4

459

14.

Ghasipura Deep Enclave Vikash Nagar

0.003

0

0.001

1.4

0.113

0

0.02

5

0

1080

223

90

25

0.21

53

63

100

5

198

0.009

0.007

0.001

1.055

0.421

0

0

0.8

0.0009

1325

223

50

0.2

0.14

60

37

200

14

458

0.005

0.031

0.005

7.4

0.358

0.014

0.04

0.6

0.0015

1470

287

100

0.4

0

51

29

260

12

351

Ranhola Nathan Vihar Chander Vihar

0.01

0.048

0.004

0.382

0.011

0

0.04

0.016

0.0019

2250

425

155

75

0.71

18

62

440

2

458

0.009

0.024

0.002

0

0

0

0

0.004

0.0026

6000

1297

1140

237

1.78

75

107

1100

650

679

0.004

0.056

0.001

1.006

0.01

0

0.06

0.095

0.0019

2430

277

65

107

2.23

31

76

475

5

1007

20.

Nihal Vihar

0.011

0.031

0.006

4.879

0.496

0

0.08

0.154

0.001

2190

475

95

111

0.36

26

127

275

6

354

21.

Karampura

0.007

0.023

0.005

1.7

0.546

0.003

0.06

0.092

0.0013

3850

872

430

116

0.66

106

127

575

4

267

22.

Shashtri Nagar

0

0.053

0.003

1.667

0.031

0

0.04

8

0.0008

1100

142

115

0.2

0.05

82

21

150

7

344

23.

Roop Nagar

0.003

0.014

0.006

3.11

0.022

0

0.04

0.134

0.0028

2120

188

200

85

7.14

29

36

460

2

747

24.

Timarpur

0.006

0.047

0.001

1.615

0.149

0

0.08

0.047

0.0001

2530

305

385

261

1.25

71

96

425

3

488

25.

Nehru Vihar D-9

0.008

0.03

0.001

3.218

1.2

0.012

0.02

0.074

0.015

1255

184

25

28

2.93

68

48

150

7

466

26.

Nehru Vihar C-280

0.004

0.051

0.005

1.3

0.7

0

0.02

0.181

0.0003

755

113

32

4

0.45

40

39

73

2

259

15. 16. 17. 18. 19.