Geogenic distribution and baseline concentration of heavy metals

in sediments of the Ganges River, India

Munendra Singha,*, German Mullerb, I.B. Singha

aDepartment of Geology, University of Lucknow, Lucknow 226007, Indiab Institute of Environmental Geochemistry, University of Heidelberg, D-69120 Heidelberg, Germany

Received 27 February 2001; accepted 14 January 2003

Abstract

The search for a better understanding of heavy metal distribution in large river sediments is a major concern in the exogenic

cycling of elements through fluvial processes and in assessing the effects of anthropogenic influences. From the Asian

continent, the Ganges River contributes a significant amount of sediments to the world’s ocean. Freshly deposited sediments of

the Ganges River were analyzed from 27 locations along the 1700-km-long channel length by atomic absorption

spectrophotometry to determine heavy metal concentration. Total metal concentration in the < 20-Am-sediment fraction varies

in the range of Cr 121–200 mg/kg, Mn 1150–3070 mg/kg, Fe 34,100–46,200 mg/kg, Co 14.7–25.3 mg/kg, Ni 35–63 mg/kg,

Cu 44–69 mg/kg, Zn 87–181 mg/kg, Cd 0.41–1.31 mg/kg and Pb 18–35 mg/kg. Baseline concentration of the river sediments

was established for Cr 147 mg/kg, Mn 1764 mg/kg, Fe 40,346 mg/kg, Co 19.2 mg/kg, Ni 47 mg/kg, Cu 55 mg/kg, Zn 105 mg/

kg, Cd 0.58 mg/kg and Pb 22 mg/kg. Higher concentration of lithophile elements (Cr and Mn) than the world average indicates

that the Ganges River basin receives contribution from basic rocks in crystalline zone of the Himalayan region. In the upper

700-km-long Ganges River segments (UGR), heavy metal profiles (except for Mn) show distinct downstream decreasing trend

due to physical sorting of river sediments. River sediments of the northern Indian craton are enriched in Cr, Fe, Co, Ni and Cu.

In comparison to high sediment influx by the Himalayan rivers, the northern Indian craton rivers play insignificant role in

controlling heavy metal distribution at regional level in 1000-km-long segment of the lower Ganges River (LGR). Metal

concentration increased in the clay size fraction by a factor of 1.5–2.5 as compared to the established baseline concentration in

the < 20-Am-sediment fraction. The Ganges River sediments of the present study can be classified by Muller’s geo-

accumulation index as basically unpolluted with respect to these heavy metals. The concentration of Cr, Ni and Cu was reported

above the lowest effect level (LEL) that may have adverse effect on the biogeochemistry of the river’s environment. The Ganges

River transports 109� 103 tons Cr; 1313� 103 tons Mn; 30,020� 103 tons Fe; 14� 103 tons Co; 35� 103 tons Ni; 41�103

tons Cu; 78� 103 tons Zn; 0.43� 103 tons Cd and 16.4� 103 tons Pb annually to the Bay of Bengal. The extensive physical

weathering of the Himalayas and monsoon-controlled fluvial process results in the strong homogenization in heavy metal

distribution in the river sediments.

D 2003 Elsevier Science B.V. All rights reserved.

Keywords: Heavy metals; Baseline concentration; Sediment geochemistry; Ganges River

0375-6742/03/$ - see front matter D 2003 Elsevier Science B.V. All rights reserved.

doi:10.1016/S0375-6742(03)00016-5

* Corresponding author. Tel.: +91-522-2324798; fax: +91-522-2222061.

E-mail address: smunendra@usa.net (M. Singh).

www.elsevier.com/locate/jgeoexp

Journal of Geochemical Exploration 80 (2003) 1–17

1. Introduction

Rivers of the Asian continent are the chief trans-

porting agents of continental weathering products as

they supply about 30% of the global sediment input to

the world’s ocean. The Indus and Ganges–Brahma-

putra Rivers contribute as much as 20% of the global

sediment input (Milliman and Meade, 1983). Consid-

ering the sediment transport of 744� 106 tons/year,

the Ganges River is placed as the third largest trans-

porting river in the world, after the Yellow and

Amazon Rivers (Subramanian et al., 1987a). The river

also carries more than 2% of the total flow of water

available in the world’s existing river systems (Rao,

1979). Given the current state of water and sediment

discharges, our interest is to couple fluvial processes

and geochemistry of the Ganges River to understand

occurrences, distribution and transportation of heavy

metals in river sediments of the Asian continent.

Baseline concentration is defined as 95% of the

expected ranges of metal concentration around a mean

in a normal sample (Kabata-Pendias et al., 1992). It

represents natural heavy metal content (background)

in samples without human or urban influences in an

idealized situation. It also accommodates information

for naturally occurring high concentration of heavy

metals of a region. This baseline concentration is

essential in understanding the biogeochemical behav-

ior of metals in a river ecosystem. In order to

determine the anthropogenic-induced heavy metal

concentration in river sediments, it is imperative to

have a proper assessment of the baseline concentra-

tion of various heavy metals. Due to long transport of

contaminants in a river environment, it is a difficult

task to establish a baseline concentration, as truly

pristine ecosystems may no longer exist. For example,

background levels of Pb are commonly elevated due

to long-term uses of Pb-based petrol and paints. Thus,

it is impossible to collect a sediment sample com-

pletely free of Pb contamination (Fergusson, 1990).

Since it is becoming more difficult to determine the

background levels of certain elements due to strong

human interference in the environment, baseline con-

centration is the only means to establish reliable

worldwide elements concentration in natural material

(Kabata-Pendias et al., 1992).

The Ganges River serves as a lifeline for about 400

million people living in its alluvial and delta plains,

one of the most densely populated and highly agricul-

tural regions of the world. Heavy metals in water and

sediments of the Ganges River may have a substantial

detrimental effect on the environment of alluvial plain

and delta regions due to their toxicity and accumu-

lation in microorganisms, plants, animals and humans.

Hence, knowledge of heavy metal concentration and

distribution in sediments is of fundamental importance

in an environmental study of the Ganges River. Some

studies on the distribution of heavy metals in sedi-

ments of the Ganges River and its tributaries have

been carried out (Ajmal et al., 1983; Subramanian et

al., 1985, 1987a; Saikia et al., 1988; Jha et al., 1990;

Mehrotra et al., 1991; Kumar, 1992; Singh et al.,

1996; Datta and Subramanian, 1998; Ansari et al.,

2000a,b; Ramesh et al., 2000; Singh, 2001). All these

studies reported either the regional distribution of

heavy metal in river sediments without any grain size

consideration or investigated metal concentration at

local scales dealing with an industrial urban center

settled on the river or on the river tributaries. A more

detailed data base on heavy metal distribution in

sediments of the Ganges River, therefore, is required

to establish baseline concentration, which can be

useful for government and environment regulatory

agencies as sediment quality guideline of the river.

Keeping in view the significance of the Ganges

River, the present study was conducted (i) to deter-

mine heavy metals (Cr, Mn, Co, Fe, Ni, Cu, Zn, Cd

and Pb) distribution and to establish their present-day

baseline concentration in the freshly deposited sedi-

ments of the Ganges River, (ii) to infer the status of

the river sediment quality, (iii) to study grain size

control on the concentration of heavy metals; (iv) to

discuss the controlling factors that affect the longitu-

dinal distribution of heavy metals in the Ganges River

sediments and (v) to estimate heavy metal fluxes to

the Bay of Bengal.

2. Study area

2.1. Regional setting

The 2525-km-long Ganges River originates from

the Gangotri glaciers in the Himalayan mountains at

an elevation of 4100 m above mean sea level. It drains

an area of about 10.86� 105 km2 and flows into the

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–172

Bay of Bengal (Rao, 1979). Geomorphologically, the

Ganges River system has four basic components, the

Ganges River, the Ganges River basin, the Ganges–

Brahmaputra delta and the Bengal fan (Fig. 1). The

Ganges River acts as a pathway for water and sedi-

ment discharges from the river basin to other

geomorphic components. The Ganges River basin

encompasses the Himalayan orogenic belt with deep

valleys and glaciers in the North, plateau and hills of

the Indian craton region in the South, and the Ganges

Alluvial Plain (GAP) in the middle, accounting for

21.6%, 55.4% and 23.0% of the river basin area,

respectively. Along with the Brahmaputra River, the

Ganges River is responsible for the creation of the

world’s largest delta plain, the Ganges–Brahmaputra

delta and the world’s largest deep sea fan, the Bengal

fan.

The Yamuna River, a major tributary, joins the

Ganges River at Allahabad. From Haridwar to up-

stream of Allahabad, the river segment is classified as

the upper Ganges River (UGR). This part of the river

segment is characterized by water and sediments

derived from the Himalayan region by the Ganges

and Ramganga Rivers. Whereas downstream of Alla-

habad, the lower Ganges River (LGR) stretch has an

additional water and sediment sources from the north-

ern Indian Craton region by the Chambal, the Betwa,

the Ken (the Yamuna River tributaries), the Son, the

Phalgu and the Punpun Rivers. The main Himalaya

rivers joining the LGR are the Ghaghra, the Gandak

and the Kosi Rivers. The Chambal, the Ken and the

Betwa Rivers drain a total area of aboutf 440,000

km2 in the northern Indian craton composed of the

Vindhyan rocks (limestones, shales and sandstones)

and the Bundelkhand granite. The UGR and LGR

stretches broadly represent the Ganges River sedi-

ments (GRS) derived from the Himalaya and the

Himalaya–Indian craton regions, respectively.

Fig. 1. The Ganges River and its geomorphic system. The Ganges River collects water and sediments from its basin and transports into the

Ganges–Brahmaputra Delta and the Bay of Bengal regions. The Ganges River in the Ganges Alluvial Plain is divided into upper (Haridwar to

Allahabad) and lower (Allahabad to Farakka) segments.

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–17 3

2.2. Climate and hydrology

According to the Koppen classification, the Ganges

River basin has a humid subtropical climate. It is

characterized by a monsoonal regime of heavy rainfall

during the months of July, August and September.

Usually 70–80% of the total annual rainfall occurs

during this period. Monsoon climate-controlled hy-

drology of the Ganges River plays an important role

in its erosion, transportation and deposition processes.

Hydrograph of the Ganges River is peaked, charac-

terized by low flows during the post- and pre-mon-

soon season and by extremely high flows during

monsoon season (Fig. 2A). About 80% of the annual

discharge of the river flows during the monsoon

season. The Ganges River has a discharge of 24,000

million m3 annually at Balawali (near Haridwar) and

459,000 million m3 annually at Farakka (Dasgupta,

1984). In these locations, the Ganges River enters into

the GAP and the delta regions, respectively. The

annual discharges increase nearly 18-fold from Bala-

wali to Farakka due to significant contribution

(f 60%) from tributaries, namely, the Yamuna, the

Ghaghara, the Gandak and the Son Rivers. Fig. 2B

shows a seasonal variation in the discharge of the

river during summer, monsoon, post-monsoon and

winter at the Balawali and Azamabad locations. The

Ganges River drains the largest river basin of the

Indian subcontinent and carries 33% of the water

flowing in the Indian river systems.

The river basin supplies vast quantities of sedi-

ments from the erosion of the Himalaya and the

northern Indian craton regions and by sheet erosion

of the GAP region. The intensity of the monsoon acts

as a first-order control of the erosion rate (2.9 mm/

year) in the Himalayan region (Galy and France-

Lanord, 2001). Consequently, the Ganges carries a

heavy sediment load in the order of several hundred

million tons annually (574� 106 tons/year as repor-

ted by Milliman and Meade, 1983; 744� 106 tons/

year by Subramanian et al., 1987a). The river trans-

ports most of its sediment load (f 70 to 80%) during

the monsoon season due to its high water discharge

and has the potential to influence the marine system

of the Bay of Bengal. An estimate shows that about

one-third of the river sediment is deposited in the

subaerial delta plain, one-third in the subaqueous

delta on the shelf, and one-third goes to the deep

sea fan (Kuehl et al., 1989). The river deposits only a

small percentage of its annual sediment load in active

channel areas as mid-channel and point bars and on

its floodplains in upstream of the delta region. The

hydrogeochemistry of the Ganges River water indi-

cates moderate alkalinity (7.8–8.5 pH) and hardness

with concentration of alkali metals (Bhatt and

Saklani, 1996). The location and lithology of the

Himalaya appear to control the chemical composition

of the Ganges River water, with total dissolved solids

ranging from 6 to 880 mg/l (Galy and France-Lanord,

1999).

Fig. 2. (A) Hydrograph of the Ganges River at Farakka (after Rao, 1979). (B) Variability in seasonal discharge of the Ganges River at Balawali

(near Haridwar) and Azamabad (near Farakka) stations as shown in Fig. 1 (after Dasgupta, 1984).

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–174

2.3. Geology

A geological map of the study area drained by the

GangesRiver system is shown in Fig. 3. TheHimalayan

region is composed of four units separated by major

thrust systems. These units are the Tethyan sedimentary

zone composed of Palaeozoic–Mesozoic carbonates

and clastic sediments; the high Himalayan Crystalline

consists of orthogneisses, paragneisses, migmatites and

highly metamorphosed marbles; the lesser Himalaya

consists of metamorphosed and un-metamarphosed

Precambrian sequences; the outer Himalayan belt con-

sists of the recently uplifted Siwaliks of Mio-Pliocene

detrital sediments, namely, coarse sandstones, clays and

conglomerates. In the Indian craton region, the Ganges

River basin consists of the Aravalli Range, the Bun-

Fig. 3. Geological map of the study area showing the location of sediment samples of the Ganges River at (1) Hastinapur, (2) Garhmukteshwar,

(3) Anupshahar, (4) Farrukhabad, (5) Kannuj, (6) Araul, (7) Radhan, (8) Bithur, (9) Kanpur, (10) Baksar, (11) Kalakankar, (12) Kara, (13)

Jahanabad, (14) Manaiya, (15) Sirsa, (16) Lachhagir, (17) Gopiganj, (18) Kachhwa, (19) Kaithi, (20) Ghazipur, (21) Buxar, (22) Barh, (23)

Mokama, (24) Munger, (25) Sultanganj, (26) Bhagalpur and (27) Farakka. The craton draining tributaries (the Chambal, the Betwa and the Ken

Rivers) were also sampled for the present study.

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–17 5

delkhand Plateau, the Vindhyan Range, the Malwa

Plateau and the Chotanagpur Plateau, which are mainly

composed of various rock types of mostly Archean and

Proterozoic ages. The exposed sediments of the GAP

represent the alluvial filling of sediments derived from

the Himalaya and northern Indian Craton regions dur-

ing late Pleistocene to Holocene. A detailed geology of

the GAP has been described elsewhere (Singh, 1987,

1996).

The Ganges River and its basin encompasses an

immense and complex area with diverse river hydrol-

ogy and basin lithology. Therefore, it provides a

prominent area for studying the controlling factors

of heavy metal distribution in river sediments, heavy

metal fluxes of rivers by transportation of continental

weathering products to ocean, insight into the average

chemical composition of continental crust and assess-

ing physical and chemical processes on a global scale

(Milliman and Meade, 1983; Taylor and McLennan,

1985).

3. Material and methods

3.1. Sediment sampling and size separation

Field studies were carried out in the pre-monsoon

period of May 1993, representing lean flow condition

of the Ganges River. Freshly deposited fine-grained

surface sediment samples were collected from the top

5–10 cm of the riverbed. These samples were taken

either in the middle or near the margins of the river’s

active channel. Twenty-seven sampling stations (1–

27) were selected from the 1700-km-long stretch of

the river as shown in Fig. 3. Three samples from the

Ken, the Betwa and the Chambal Rivers were also

collected. All sampling sites were located outside the

area of anthropogenic (urban and industrial) influen-

ces. The < 20-Am-sediment fraction size was used in

this study in order to minimize grain size depend-

encies of heavy metal concentration in the river sedi-

ments. Required granulometric fraction was separated

from the collected samples by mechanical wet sieving

method using nylon sieves and double distilled water.

Additionally, few sediment samples were also sepa-

rated into the < 63-Am and the < 2-Am fractions to

assess grain size control on heavy metal concentration

in these sediments.

3.2. Analytical techniques

A total digestion method after Ruppert (1987) and

Jackwerth and Wurfels (1994) was used for heavy

metal analysis. One hundred milligrams of sieved

sediment fraction of the GRS was digested in closed

Teflon beakers to completely dissolve the sediments

by using HClO4, HNO3 and HF acids at 150 jC for 5

h. Upon cooling of these Teflon beakers, the solutions

were fumed at 180 jC for about 11 h. After the

fuming process, brownish-black residue was left at

the bottom of each Teflon beaker. It was taken up with

1 ml of nitric acid and distilled water from the Teflon

beaker and transferred into 50-ml volumetric flasks.

These solutions were directly analyzed for Cr, Mn, Fe,

Co, Ni, Cu, Zn, Cd and Pb with Perkin-Elmer Atomic

Absorption Spectrophotometer models 3030 and 4100

by flame and graphite furnace methods. Certified

stream sediment STSD-3 was used as standard for

evaluating the precision and accuracy of the above

analytical procedure. For quality control, standard,

duplicates and analytical blanks were prepared and

analyzed using the same procedure and reagents. The

results were within the range of the certified values

(Singh, 1996). Maximum care was taken to avoid

external contamination by using chemicals of analyt-

ical grade and double distilled water. The above

chemical analysis was performed at the laboratories

of the Institute of Environmental Geochemistry, Uni-

versity of Heidelberg.

4. Results and discussion

4.1. Metals distribution

Table 1 presents the heavy metal concentration in

the < 20-Am fraction of sediments of the Ganges

River along with the selected northern Indian craton

draining tributaries. Heavy metal concentration in the

< 63-Am and the < 2-Am-sediment fractions of some

samples is also presented in Table 2. Results show

the metal concentration in the GRS has a range of Cr

121–200 mg/kg, Mn 1150–3070 mg/kg, Fe 34,100–

46,000 mg/kg, Co 14.7–25.3 mg/kg, Ni 35–63 mg/

kg, Cu 44–69 mg/kg, Zn 87–181 mg/kg, Cd 0.41–

1.31 mg/kg and Pb 18–35 mg/kg. No prominent

variation has been found in the calculated values of

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–176

the average, median and geometric mean of these

ranges (Table 1). Values of the maximum and mini-

mum ratio for Cr, Fe, Co, Ni, Cu and Pb range from

1.3 to 2.0 followed by Mn and Zn with 2 to 3 and for

Cd 3.2. It shows a narrow range of the distribution of

heavy metals in the GRS. The calculated geometric

mean values are Cr 147 mg/kg, Mn 1764 mg/kg, Fe

40,346 mg/kg, Co 19.2 mg/kg, Ni 47 mg/kg, Cu 55

mg/kg, Zn 105 mg/kg, Cd 0.58 mg/kg and Pb 22 mg/

kg. These values represent the lithogenic baseline

concentration of heavy metals for the GRS and also

accommodate information for naturally occurring

high heavy metal concentration in the Ganges River

basin.

Table 1

Heavy metal concentration (mg/kg) in the < 20-Am-sediment fraction of the Ganges River (1–27) and the northern Indian craton draining

tributaries of the Ganges River system

Sample no. Cr Mn Fe Co Ni Cu Zn Cd Pb

1 136 1250 39,200 19.6 50 53 104 1.31 19

2 152 1815 46,000 23.6 45 69 98 0.47 29

3 142 1650 41,300 22.7 55 59 99 0.60 27

4 134 1470 40,000 19.2 59 59 111 0.66 24

5 160 2080 45,300 21.0 55 56 99 0.66 23

6 141 1635 40,300 23.0 45 48 98 0.66 21

7 137 2125 40,400 18.0 60 48 94 0.50 22

8 136 1425 38,900 21.0 47 44 101 0.50 20

9 121 2565 34,100 16.5 37 59 104 0.47 26

10 132 3070 41,800 23.0 35 49 106 0.50 20

11 148 1530 41,900 25.3 45 57 89 0.41 24

12 130 1910 37,600 18.7 40 52 100 0.62 21

13 130 2430 36,000 18.5 38 52 97 0.60 20

14 151 1850 39,500 16.5 40 53 87 0.56 21

15 150 1570 38,800 22.1 63 53 132 0.50 20

16 133 1840 36,000 18.0 45 48 94 0.50 18

17 162 1660 43,200 19.6 52 62 132 0.50 24

18 150 2480 40,600 17.6 62 56 94 0.50 20

19 144 1605 36,400 16.2 46 52 110 0.75 21

20 147 1150 36,800 16.5 41 49 94 0.72 18

21 163 1690 42,700 23.5 56 58 108 0.62 19

22 155 1660 42,200 16.3 50 57 99 0.60 21

23 200 1410 42,500 22.1 41 58 171 0.56 35

24 165 1715 43,700 19.4 48 59 102 0.62 24

25 158 1715 43,500 15.3 62 66 181 0.56 22

26 142 1740 39,700 14.7 37 55 97 0.56 20

27 167 1725 43,900 17.1 43 56 94 0.62 25

Minimum 121 1150 34,100 14.7 35 44 87 0.41 18

Maximum 200 3070 46,000 25.3 63 69 181 1.31 35

Maximum/minimum Ratio 1.65 2.67 1.35 1.72 1.80 1.57 2.08 3.20 1.94

Average 148 1806 40,456 19.0 48 55 107 0.60 22

Median 147 1715 40,400 19.2 46 56 99 0.56 21

Geometric mean 147 1764 40,346 19.2 47 55 105 0.58 22

Standard deviation 16.05 424 3018 2.93 8.48 5.68 22.45 0.16 3.72

Cratonic tributaries

Betwa River 212 1435 51,000 35.5 89 69 108 0.44 19

Chambal River 197 1950 50,900 29.8 89 64 113 0.53 19

Ken River 189 1590 48,000 27.8 89 65 107 0.50 13

Geometric mean 199 1644 49,947 30.9 89 66 109 0.49 17

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–17 7

4.2. Longitudinal dispersion

Heavy metal concentration in river sediments

results from the competing influences of river basin

geology, physical and chemical weathering, diagene-

sis, sediment texture and the aqueous geochemistry of

individual metals (Rollinson, 1993). Generally, down-

stream changes in heavy metal concentration in sedi-

ments of a river are controlled by the geochemical

characteristics of its tributaries and are related to the

subsurface geology. Fig. 4 shows the 1700-km-long

downstream heavy metal profiles of the GRS. Their

UGR and LGR segments are discussed separately as

follows.

4.2.1. The Upper Ganges River

The 700-km-long UGR segment provides informa-

tion on the regression relations and correlation among

metals to understand the behavior during fluvial trans-

port of the Himalayan-derived sediments. The highest

concentration of Mn, Fe, Co, Cu and Cd in longitu-

dinal distribution was recorded in the upper part of

this segment as 3070 mg/kg; 46,000 mg/kg; 25.3 mg/

kg; 69 mg/kg and 1.31 mg/kg, respectively (Table 1).

Metal mobility in a fluvial system mainly depends

upon the pH and Eh. In the rivers where the pH

remains slightly basic (7.8–8.5), metal mobility in the

sediment phase is restricted (Aulio, 1987). Regression

and correlation relationships of heavy metal distribu-

tion in sediments and downstream distance of the

upper Ganges River segment are presented in Table

3. All the metals show downstream decreasing trends

except Mn. Consequently, the profile of Fe/Mn ratio

in the particulate phase of the UGR segment decreases

downstream due to downstream increase in Mn and

decrease in Fe (Fig. 5A). An inter-element relation-

ship has been observed between Fe–Cr (r2 = 0.81),

Co–Cr (r2 = 0.42), Co–Fe (r2 = 0.50) and Cu–Pb

(r2 = 0.75). High positive correlation between these

metals indicates a common source in minerals of their

metal concentration in the GRS. Fig. 5B shows the

regression and correlation among Fe and Cr in sedi-

ments of the UGR.

4.2.2. The Lower Ganges River

In the 1000-km-long LGR segment, downstream

profiles of heavy metal concentration in the GRS are

characterized by prominent isolated peaks at 23, 24

and 25 sampling stations within a narrow range of

geogenic variation for all metals, except Fe, Mn and

Table 2

Heavy metal concentration (in mg/kg) in the < 63-Am and the < 2-Am-sediment fractions of the Ganges River and the northern Indian craton

draining tributaries at various sampling stations

Sample no. Fraction

(Am)

Cr Mn Fe Co Ni Cu Zn Cd Pb

Ganges River

2 < 63 112 1290 35,300 22 33 45 95 0.56 22

7 < 63 118 1740 35,500 15 48 39 70 0.53 19

13 < 63 83 1490 25,800 20 35 30 92 0.53 16

17 < 63 156 1640 44,100 21 48 53 126 0.47 23

22 < 63 133 1435 39,100 17 43 47 93 0.44 21

Geometric mean 118 1511 35,420 19 41 42 94 0.50 20

Ganges River

2 < 2 261 774 80,900 32 58 110 188 1.43 54

13 < 2 239 1210 67,000 34 52 72 147 1.72 48

17 < 2 279 1866 77,400 31 52 79 156 1.02 49

22 < 2 271 1078 78,000 38 49 81 138 0.82 45

Geometric mean 262 1172 75,634 34 53 84 156 1.20 49

Cratonic tributaries

Betwa River < 2 272 1000 74,100 29 87 75 126 0.88 30

Ken River < 2 284 665 77,700 26 75 69 129 0.52 30

Chambal River < 2 262 810 71,800 32 72 73 124 0.48 24

Geometric mean 273 814 74,494 29 78 72 126 0.60 28

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–178

Cd (Fig. 4). The highest concentration of Cr, Zn, Ni

and Pb in longitudinal distribution was recorded in the

lower part of this segment as 200, 181, 63 and 35 mg/

kg, respectively. It may be a reflection of the contri-

bution of small tributaries draining from the southern

source. This is significant in that geogenic conditions

can provide high concentration of heavy metals only

at isolated sites without affecting regional distribution.

The effects of tributaries from the cratonic region are

subdued due to high sediment and water discharges

Fig. 4. Downstream variation in heavy metal concentration of the Ganges River sediments (HD—Haridwar, Al—Allahabad and FR—Farakka).

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–17 9

from the Himalayan rivers. At the same time, these

tributaries are controlling significantly the heavy

metal profiles at the local scale.

4.3. Grainsize control

Field studies along with granulometric analysis of

the collected sediment samples show that the river

sediments are predominately composed of fine sand,

very fine sand and silt along with minor amount of

medium sand and clay fractions. The < 20-Am-sedi-

ment fraction contents (medium silt to clay) in total

sediment shows a wide range from 5% to 71% with

median value of 28% (Singh, 1996). X-ray diffraction

analysis shows the presence of quartz, feldspar and

illite as main minerals in the < 20-Am-sediment frac-

tion (Singh, 1996). Suspended sediments of the

Ganges River consist predominantly of coarse to

medium silt (62–15 Am) with dominance of mica as

clay minerals (Chakrapani et al., 1995). The river

sediment fraction used for the present geochemical

studies has been well distributed in channel sediments

as well as in suspended sediments of the Ganges River.

Physical sorting is the geogenic factor that most

strongly influences heavy metal composition in indi-

vidual samples (Sawyer, 1986). Textural composition

of river sediment plays an important role in the study

of bioavailability of heavy metals and toxicity of

sediments as these metals are not homogeneously

distributed over various grain size fractions. Relation-

ship between grain size and concentration of heavy

metals in the GRS was examined by considering metal

concentration in the < 20-Am-sediment fraction as unit

(Fig. 6A). Except Mn, metal concentration increases

towards the < 2-Am-sediment fraction by a factor of

1.5 for Co and Cu, 1.6 for Zn, 1.75 for Fe and Cr, 2 for

Pb and 2.5 for Cd. Increasing heavy metal concen-

tration in the finer grain sizes of river sediments has

also been reported in earlier studies (Gibbs, 1977;

Solomons and Forstner, 1984). In the < 63-Am-frac-

tion, metal concentration decreased by a factor of 0.8

Table 3

Regression and correlation relationships of heavy metal distribution

in sediments and downstream distance of the upper Ganges River

segment

Heavy metals Regression, y = ax + b Correlation (r2)

Cr y=� 0.02x+ 153 0.13

Mn y= + 1.34x+ 915 0.22

Fe y=� 7.93x+ 46,149 0.20

Co y=� 0.002x+ 23 0.04

Ni y=� 0.02x+ 62 0.21

Cu y=� 0.02x+ 67 0.24

Zn y=� 0.007x+ 105 0.06

Cd y=� 0.0006x + 1.1 0.27

Pb y=� 0.007x+ 27.9 0.17

Number of observations = 13.

Fig. 5. (A) Downstream changes in the Fe/Mn ratio. (B) Scatter plot of Fe and Cr in the sediments of the upper Ganges River (number of

observations = 13).

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–1710

for Co and Pb in the sediments with no change in the

concentration for Cd and Zn. A general decrease of

metal content in coarse fraction of the sediments is due

to the dilution effect of an increase in quartz and

feldspar contents (Horowitz, 1991). In comparison to

the < 2-Am-sediment fraction of the Ganges River, the

Indian carton draining tributaries are enriched in Ni

and depleted in Mn, Zn, Cd and Pb (Table 2).

The Ganges River is a subcontinental scale river

and its sediment composition integrates a diversity of

continental lithologies. The mean chemical composi-

tion of all major geological units of the Himalaya is

relatively similar to that of the average of the Upper

Continental Crust (UCC) of Taylor and McLennan

(1985). To determine the textural dependency of

heavy metal concentration in the GRS, the overall

Fig. 6. (A) Grain-size control on the heavy metal enrichment considering metal concentration in the < 20-Am-sediment fraction as unit. Most of

the metals show high concentration in clay fraction. (B) Heavy metal concentration in various sediment fractions from the Ganges River

normalized to the average Upper Continental Crust. Data for suspended and bulk sediments of the Ganges River from Subramanian et al.

(1987b). Heavy metals plotted from left to right in the order of increasing atomic number.

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–17 11

distribution of heavy metals in various sediment

fractions was normalized to the average of the UCC

(Fig. 6B). The GRS are slightly enriched in Zn, Cd

and Pb as compared to other metals. Differences

between the bulk sediment and the < 2-Am-sediment

fractions were accentuated in the suspended, the < 63-

Am and the < 20-Am fractions. Ni and Zn are more

associated with suspended sediment, while Pb is

clearly enriched with the < 2-Am-sediment fraction

as demonstrated by its higher abundance in the sedi-

ments. The stable trend of Cr, Mn, Fe and Co, and the

increasing trend of Ni, Cu, Zn Cd and Pd with

increasing atomic number, was also observed. Ansari

et al. (2000a) determined heavy metals in various

sediment fractions of the GRS near Kanpur and found

that heavy metal concentrations were very high in the

coarse sand and also in the clay fractions of the river

sediments. High concentration of heavy metals in the

coarse fraction of the GRS is linked to the high

content of degraded mica and organic debris.

4.4. Metal ratio

Metal ratios were calculated from the established

baseline concentration of the present study to asses the

extent of downstream geogenic variations in heavy

metal concentration in the GRS. In Fig. 7, the box and

whisker plot shows the distribution of metal ratios at

various percentiles at the regional level. Major dis-

tribution (5 to 95 percentiles) of heavy metals occurs

in a symmetrically skewed way within a narrow zone

of metal ratios. Most of the metals derive their

concentration within a narrow limit of variation

emphasizing the significance of the geogenic factors

of the Ganges River basin over heavy metal distribu-

tion in the GRS.

Fig. 8A shows the longitudinal profiles of metal

ratio along the Ganges River. These profiles show a

narrow range of downstream variation around the

established baseline concentration along with distinc-

tive isolated peaks. The important geogenic factors

that may distinctly control heavy metal concentration

and distribution in river sediments of the UGR and

LGR segments are source area as these river segments

broadly represent sediments derived from the Hima-

layan and the Himalayan–northern Indian cratonic

regions, respectively. Heavy metal concentration in

these river sediments will reflect geogenic effects as

similar grain-size fractions were used in this study.

The downstream variation may be explained by local

variation in quartz content due to various inputs from

tributaries and a wide range of the < 20-Am-sediment

Fig. 7. Box and whisker plot of the 10th, 25th, 50th, 75th and 90th percentiles of metal ratio in sediments of the Ganges River. Lines indicate

maximum and minimum values.

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–1712

fraction (5–71%) of the samples in the GRS. Cumu-

lative metal ratio was also calculated by adding the

ratios of all nine metals at each sampling station, and

its downstream variation is shown in Fig. 8B. The

downstream variation of the cumulative metal ratio in

the Ganges River is characterized by a distinct

decrease in the upper reaches (UGR) and a slight

increase in the lower reaches (LGR) of the Ganges

River. Physical sorting in the UGR and the craton

tributary inputs in the LGR are the main factors

responsible for these distinctive trends of the profile.

It indicates that geogenic-controlled heavy metal var-

iation of the Ganges River basin is not reflected in the

river sediments on a regional scale. The fluvial

processes seem to equalize the different heavy metal

contributions from different geological setups in the

study area.

River basin lithology, physical and chemical weath-

ering processes, sorting of weathering products and

post-depositional changes during diagenesis are the

main factors that control the geochemistry of clastic

sediments (Sawyer, 1986). Fig. 9 shows a bar diagram

Fig. 8. (A) Downstream changes in the metal ratios, calculated with respect to established baseline concentration of heavy metals in the

sediments of the Ganges River (number of observations = 27). (B) Downstream variation in cumulative metal ratio of the Ganges River

sediments. It shows a distinct decrease in the upper Ganges and a slight increase in the lower Ganges River segments.

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–17 13

of the metal ratio calculated from the established base-

line concentration and geometric mean of heavy metal

concentration in the GRS derived from the Himalaya,

the northern Indian craton and mixed from both

regions. River sediments of the craton region show

distinct high metal contents for Cr, Fe, Co, Ni and Cu.

These high metal contents are attributed to the varying

lithology of drainage basins of the northern Indian

craton from where river sediments were derived. These

metals have high concentration in rocks of ultramafic

and basaltic nature (Turekian and Wedepohl, 1961),

suggesting a significant contribution from such rocks in

the Indian craton-derived sediments. In the mixed

region of the Himalayan and the northern Indian craton,

the metal contents are reduced nearly to the metal

contents of the Himalayan region. This can be

explained by the high sediment supply from the Hima-

layan source as compared to the cratonic source.

4.5. Sediment quality assessment

A quantitative measure of the extent of metal pol-

lution in the GRS was calculated using the geo-

accumulation index proposed by Muller (1979). It is

expressed as:

Geo�accumulation index ¼ log2Cn=1:5Bn

where Cn =measured concentration; Bn= background

value (average shale) of element n and 1.5 = back-

ground matrix correction factor.

The geo-accumulation index consists of seven

grades (0 to 6), indicating various degrees of enrich-

ment above the background values ranging from

unpolluted to very highly polluted sediment quality.

The calculated index values for the GRS are given in

Table 4 and remain in either class 0 or class 1, which

indicates that investigated samples along the 1700-

km-long channel length, the GRS are unpolluted. It

may be pointed out that near urban/industrial centers

of the GAP, river sediments show a prominent through

variable degree of heavy metal enrichment (Singh et

al., 2002).

Freshwater sediment quality guidelines provide

another criteria for the evaluation of heavy metal con-

centration in river sediments in response to adverse

Fig. 9. Bar diagram showing metal ratios in river sediments derived from the Himalayan, the northern Indian craton and mixed from both

regions. Metal ratios were calculated with respect to the baseline concentration of heavy metal in the Ganges River sediments.

Table 4

Geo-accumulation indices (after Muller, 1979) of heavy metal

concentration in sediments of the Ganges River

Geo-accumulation

index

Sediment quality Heavy metals

0 Background

concentration

Fe, Co, Ni, Cu

1 Unpolluted Cr, Mn, Zn, Pb, Cd

2 Moderately to

unpolluted

3 Moderately polluted

4 Moderately to

highly polluted

5 Highly polluted

6 Very highly polluted

The heavy metal concentrations fall in categories 0 and 1.

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–1714

affects on the river’s biological components. Table 5

presents a comparative study of the base level heavy

metal concentration in the GRS with concentration of

lowest effect level (LEL) and probable effect level

(PEL). In the LEL, sediments are considered to be clean

to marginally polluted, but no effects on the majority of

sediment-dwelling organisms are expected below this

concentration (Persaud et al., 1993). The PEL repre-

sents the level above which adverse effects to aquatic

biota are predicted to occur frequently (Smith et al.,

1996). Using this approach in the natural nonpolluted

GRS, Cr and Ni are identified above the PEL and LEL

concentrations; whereas Cu is identified only above the

LEL concentration. These metals may cause or con-

tribute sediment toxicity to the freshwater ecosystem of

theGangesRiver. Future investigations should focus on

the potential bioaccumulation of Cr, Ni and Cu in

aquatic organisms and associated hazards that consume

aquatic organisms (i.e. animals, plants and humans) in

the Ganges River system.

4.6. Comparison to other studies

Heavy metal concentration in the sediments of the

Ganges and other river basins of India, average shale

values given by Turekian and Wedepohl (1961), and

world average are presented in Table 6. Comparative

results with sediments of the Cauvery River (a 800-

km-long river in southern India draining an area of

about 87,900 km2 having gneiss, charnockite and

granites lithologies) indicate that geogenic factors

may have no distinct control over the Co and Pb

contents in river sediments. The Indian average of

these heavy metals is based on the analysis of bulk

river sediments (Subramanian, 1987a). All reported

values of the Ganges River, therefore, are on the

higher side of the Indian average due to the analysis

of the fine sediment fraction. Indian average data,

therefore, needs further improvement keeping in mind

metal concentration dependency on size fraction ana-

lyzed. The world average values for Ni, Cu, Zn are on

the higher side and Cr on the lower side of the values

of the GRS. Except Co, the concentration of other

heavy metals in the GRS is not comparable with

respect to average shale. The concentration of Cr

and Mn in the GRS is higher than other literature

values. These are the only two-lithophile elements in

Table 5

Comparative study of base level concentration (mg/kg) of heavy

metals in sediments of the Ganges River with lowest effect level

(Persaud et al., 1993) and probable effect level (Smith et al., 1996)

in sediments of fresh water system

Heavy

metals

Ganges River

sediments

Lowest

effect level

Probable

effect level

Cr 150 26 90

Mn 1715 – –

Fe 40,400 – –

Co 21 – –

Ni 46 16 36

Cu 55 16 197

Zn 106 120 315

Cd 0.55 0.6 3.53

Pb 23 31 91.3

Table 6

Comparison study of heavy metal concentration (mg/kg) in sediments of the Ganges River with other river systems in India and the world

Heavy

metals

Ganges River

sediments

Yamuna River

sediments

Ganges Delta

sediments

Bay of Bengal

sediments

Cauvery

sediments

Average

shale

Indian river

sediments average

World

average

1 2 3 4 5 6 7 8

Cr 147 70 97 84 95 90 87 100

Mn 1765 460 1075 529 560 850 605 1050

Fe 40,350 25,000 48,800 39,800 29,950 46,000 29,000 48,000

Co 19 – – – 25 19 – 20

Ni 47 20 28 64 55 68 37 90

Cu 55 40 25 26 26 45 28 100

Zn 105 70 76 – 92 95 16 350

Cd 0.58 – – – 2.1 0.30 – –

Pb 22 – 17 – 20 20 – –

Data sources: (1) present study (the < 20-Am-sediment fraction); (2) Jha et al. (1990) (bulk sediments); (3) Datta and Subramanian (1998) (the

< 63-Am-sediment fraction); (4) Sarin et al. (1979); (5) Vaithiynathan et al. (1993) (bulk sediments); (6) Turekian and Wedepohl (1961); (7)

Subramanian et al. (1987a); (8) Martin and Meybeck (1979).

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–17 15

the present study. High Cr and Mn concentrations in

the GRS indicate contribution from erosion of the

basic rocks of the crystalline Himalaya.

4.7. Fluxes to the Bay of Bengal

Assessing heavy metal flux by the Ganges River is

of primary importance in our understanding of the

exogenic cycle of heavy metal through the present

fluvial processes in humid subtropical climate. The

present estimation was done based on the baseline

concentration of heavy metals and sediment budget of

744� 106 tons/year. To some extent, the baseline

concentration of heavy metals established in this study

in the < 20-Am-fraction of the GRS may be considered

to represent the middle value of the river sediments.

The suspended sediments will be enriched and bed

sediments will be depleted in heavy metals as com-

pared to the baseline concentration of the Ganges

River. The Ganges River contributes 109� 103 tons

Cr;1313� 103 tonsMn;30,020� 103 tonsFe;14� 103

tons Co; 35� 103 tons Ni; 41�103 tons Cu; 78� 103

tons Zn; 0.43� 103 tons Cd and 16.4� 103 tons Pb

annually to the Bay of Bengal. The present study of

the GRS is more significant as the Himalayan rivers

supply more than 90% of the total sediment inputs to

the Bay of Bengal, which is one of the highest

terrigenous input sites in the world’s ocean.

5. Conclusions

Geogenic distribution of heavy metals in the GRS

is the representation of fluvial processes operating on

the Asian continent under monsoon-controlled humid

subtropical climate. The intensive physical weather-

ing and erosion of the Himalaya results in strong

modification of heavy metal distribution in river

sediment towards homogenization and plays a sig-

nificant role in controlling a narrow range of the

distribution of heavy metals in river sediment on a

regional scale. Baseline concentration of the Ganges

River sediments was established for Cr 147 mg/kg,

Mn 1764 mg/kg, Fe 40,346 mg/kg, Co 19.2 mg/kg,

Ni 47 mg/kg, Cu 55 mg/kg, Zn 105 mg/kg, Cd 0.58

mg/kg and Pb 22 mg/kg. The present study provides a

global view of heavy metal concentration in sedi-

ments of the Ganges River and may act as sediment

quality guideline for government and environmental

organizations for reference values in assessing anthro-

pogenic vs. geogenic inputs in environmental studies.

As a major sediment transporting system in the world,

the Ganges River contributes significantly to sedi-

ment bond heavy metal load to the Bay of Bengal.

Acknowledgements

Deutschen Akademischen Austauschdienst

(DAAD), Germany, and Council of Scientific and

Industrial Research (CSIR), India, financially sup-

ported this research. Helpful suggestions made by

Prof. Dr. Jorg Matschullat, University of Freiberg, are

gratefully acknowledged. Thanks are also due to

Silvia Marhoffer and Stefan Rheinberger for their help

during metal analysis and Pramod Joshi for his help in

making diagrams. We thank Prof. Rudy Swennen for

his encouragement and two anonymous reviewers,

whose comments and suggestions have improved this

paper to a remarkable extent.

References

Ajmal, M., Khan, M.A., Nomani, A.A., 1983. Pollution in the River

Ganges (India). Water Sci. Technol. 16, 347–358.

Ansari, A.A., Singh, I.B., Tobschall, H.J., 2000a. Role of monsoon

rain on concentrations and dispersion patterns of metal pollu-

tants in sediments and soils of the Ganga Plain, India. Environ.

Geol. 39, 221–237.

Ansari, A.A., Singh, I.B., Tobschall, H.J., 2000b. Importance of

geomorphology and sedimentation processes for metal disper-

sion in sediments and soils of the Ganga Plain: identification of

geochemical domains. Chem. Geol. 162, 245–266.

Aulio, K., 1987. Enrichment of metals in a fresh water reservoir

acidified by geochemical loading. Proc. Int. Conf. Heavy Metals

in the Environment, New Orleans, vol. 2. CEP Consultants,

Edinburgh, pp. 515–517.

Bhatt, K.P., Saklani, S., 1996. Hydrogeochemistry of Upper Ganges

River, India. J. Geol. Soc. India 48, 171–182.

Chakrapani, G.J., Subramanian, V., Gibbs, R.V., Jha, P.K., 1995.

Size characteristics and mineralogy of suspended sediments of

the Ganga River, India. Environ. Geol. 25, 192–196.

Dasgupta, S.P., 1984. The Ganga Basin: Part II. Central Board for

Prevention and Control of Water Pollution, New Delhi. p. 204.

Datta, D.K., Subramanian, V., 1998. Distribution and fraction of

heavy metals in the surface sediments if the Ganges–Brahma-

putra–Meghana river system in the Bengal Basin. Environ.

Geol. 36, 93–101.

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–1716

Fergusson, J.E. (Ed.), 1990. The Heavy Elements: Chemistry,

Environmental Impact and Health Effects. Pergamon Press,

New York. 614 pp.

Galy, A., France-Lanord, C., 1999. Weathering processes in the

Ganges–Brahmaputra basin and the riverine alkalinity budget.

Chem. Geol. 159, 31–60.

Galy, A., France-Lanord, C., 2001. Higher erosion rates in the

Himalaya: Geochemical constraints on riverine fluxes. Geol.

29, 23–26.

Gibbs, R.J., 1977. Transport phases of transition metals in the Am-

azon and Yukon Rivers. Geol. Soc. Am. Bull. 88, 829–843.

Horowitz, A.J., 1991. A Primer on Sediment-Trace Element Chem-

istry. Lewis Publishers, USA. 135 pp.

Jackwerth, E., Wurfels, M., 1994. Der Druckaufschluß-apparative

Moglichkeiten, Probleme und Anwendungen. In: Stoeppler,

M. (Ed.), Probennahme und Aufschluß. Springer, Berlin,

pp. 121–138.

Jha, P.K., Subramanian, V., Sitasawad, R., Van Grieken, R., 1990.

Heavy metals in sediments of the Yamuna River (a tributary of

the Ganges). Sci. Total Environ. 95, 7–27.

Kabata-Pendias, A., Dudka, S., Chlopecha, A., 1992. Background

levels and environmental influences on trace metals in soils of

the temperate humid zone of Europe. In: Adriano, D.C. (Ed.),

Biogeochemistry of Trace Metals. CRC Press, Boca Raton, FL,

pp. 61–84.

Kuehl, S.A., Hariu, T.M., Moore, S.W., 1989. Shelf sedimentation

off Ganga–Brahmaputra river system: evidence for sedimenta-

tion bypassing to the Bengal fan. Geology 17, 1132–1135.

Kumar, S., 1992. Heavy metals in the Ganga River sediments, Uttar

Pradesh: a preliminary report. In: Singh, I.B. (Ed.), Ganga Plain:

in Terra Incognita. Geology Department, University of Luck-

now, Lucknow, pp. 59–66.

Martin, J.M., Meybeck, M., 1979. Elemental mass balance of ma-

terials carried by major world rivers. Mar. Chem. 7, 173–206.

Mehrotra, M.N., Singh, S.N., Srivastava, A., Singh, K.M., 1991.

Lead in bank sediments of Ganga and its role in water pollution.

Bull. Indian Geol. Assoc. 24 (1), 61–66.

Milliman, J.D., Meade, R.H., 1983. Worldwide delivery of river

sediments to ocean. J. Geol. 91, 1–19.

Muller, G., 1979. Schwermetalle in den sedimenten des Rheins-

Veranderungen seit 1971. Umschau 79 (24), 778–783.

Persaud, D., Jaagumani, R., Hayton, A., 1993. Guidelines for the

Protection and Management of Aquatic Sediment Quality in

Ontario. Water Resources Branch, Ontario Ministry of the En-

vironment, Toronto. p. 27.

Ramesh, R., Ramanathan, A.L., Ramesh, S., Purvaja, R., Subra-

manian, V., 2000. Distribution of rare earth elements in the

surficial sediments of the Himalaya river system. Geochem. J.

34, 295–319.

Rao, K.L., 1979. India’s Water Wealth. Oxford Univ. Press, Lon-

don. 267 pp.

Rollinson, H.R., 1993. Using Geochemical Data: Evaluation, Pre-

sentation, Interpretation. Longman, London. 352 pp.

Ruppert, H., 1987. Bestimmung von Schwermetallen im Boden

sowie die ihr Verhalten beeinflussenden Bodeneigenschaften.

Bayerisches Geologisches Landesamt, Beilage zum GLA-Fach-

bericht 2, 1–11.

Saikia, D.K., Mathur, R.P., Srivastava, S.K., 1988. Heavy metals in

water and sediments of Upper Ganga. Indian J. Environ. Health

31 (1), 11–17.

Sarin, M.M., Borole, D.V., Krishnaswami, S., 1979. Geochemistry

and geochronology of sediments from Bay of Bengal and equa-

torial Indian oceans. Proc. Indian Acad. Sci. 88A, 131–154.

Sawyer, E.W., 1986. The influence of source rock type, chemical

weathering and sorting on the geochemistry of clastic sediments

from the Quetico Metasedimentary Belt, Superior Province,

Canada. Chem. Geol. 55, 77–95.

Singh, I.B., 1987. Sedimentological history of Quaternary deposits

of the Ganga Plain. Indian J. Earth Sci. 14, 272–282.

Singh, M., 1996. The Ganga River: fluvial geomorphology, sedi-

mentation processes and geochemical studies. Heidelb. Beitr.

Umw.-Geol. Heidelberg 8, 1–133.

Singh, M., 2001. Heavy metal pollution in freshly deposited sedi-

ments of the Yamuna River (the Ganga River tributary): a case

study from Delhi and Agra urban centres. India Environ. Geol.

40, 664–671.

Singh, M., Ansari, A.A., Muller, G., Singh, I.B., 1996. Heavy

metals in freshly deposited sediments of the Gomati River (a

tributary of the Ganga River): effects of human activities. En-

viron. Geol. 29, 246–252.

Singh, M., Muller, G., Singh, I.B., 2002. Heavy metals in freshly

deposited stream sediments of rivers associated with urbanisation

of the Ganga Plain, India. Water Air Soil Pollut. 141, 35–54.

Smith, S.L., MacDonald, D.D., Keenleyside, K.A., Ingersoll, C.G.,

Field, J., 1996. A preliminary evaluation of sediment quality

assessment values for freshwater ecosystem. J. Great Lakes

Res. 22, 624–638.

Solomons, W., Forstner, U., 1984. Metals in Hydrocycle. Springer,

Heidelberg.

Subramanian, V., Van Grieken, R., Van’t Dack, L., 1985. Chemical

composition of river sediments from the Indian sub-continent.

Chem. Geol. 48, 271–279.

Subramanian, V., Sitasawad, R., Abbas, N., Jha, P.K., 1987a. En-

vironmental geology of the Ganga River basin. J. Geol. Soc.

India 30, 335–355.

Subramanian, V., Van Grieken, R., Van’t Dack, L., 1987b. Heavy

metals distribution in the sediments of Ganges and Brahmaputra

Rivers. Environ. Geol. Water Sci. 9, 93–103.

Taylor, S.R., McLennan, S.M., 1985. The Continental Crust: Its

Composition and Evolution. Blackwell, London. 312 pp.

Turekian, K.K., Wedepohl, K.H., 1961. Distribution of elements in

some major units of the earth’s crust. Bull. Geol. Soc. Am. 72,

175–192.

Vaithiynathan, P., Ramanathan, A.L., Subramanian, V., 1993.

Transport and distribution of heavy metals in Cauvery River.

Water Air Soil Pollut. 71, 13–28.

M. Singh et al. / Journal of Geochemical Exploration 80 (2003) 1–17 17