Asian Journal of Water, Environment and Pollution, Vol. 1, No. 1 & 2, pp. 41-54.

Water Quality in South Asia

V. Subramanian

School of Environmental Sciences Jawaharlal Nehru University, New Delhi-110067, * [email protected]; [email protected]

Received February 10, 2004; accepted February 10, 2004

Abstract: There are significant differences in the water chemistry of the Himalayan and southern peninsular rivers. Large and small rivers also show different types of water quality. Liquid and solid waste definitely contribute to water quality in urban centres such as Delhi and even coastal regions, as near Mumbai, are affected by waste discharges. The sub-continent also suffers from problems associated with floride and also arsenic in different parts. Even drinking water shows contamination with metals and POP. Thus over one billion people, both qualitatively and quantitatively, are at water risk. Water quality studies in such aspects as POP, heavy metals and microbiology are urgently needed—particularly in regions such as Nepal and Bhutan where data base is scanty. The intensive agricultural activity in the sub- continent is reflected in enhanced levels of nutrients in various water bodies in many parts of the region. Thus, water in south Asia may be thought no longer to represent natural water quality but shows impact of different types of human activities practically in every part of the sub-continent.

Key words: Water quality, south Asia, metals, POP.

Introduction already in this category while will follow India soon after. While the quantity of available water is With annual rainfall of over 4000 km3 and river flow of posing serious social and economic issues in the region, about 1880 km3 combined with estimated groundwater as illustrated for various countries in south Asia and for resources around 431 km3, there is no paucity of fresh urban areas in India in Figure 1a and Figure 1b water in the Indian sub-continent. Problems in the region respectively, the quality aspects also increasingly find are more about spatial and temporal discrepancies in the distribution of these huge water resources. The south Asian nations together have over 2800 km3 of renewable fresh water resources (Gleck, 1998). Due to increasing population over the last fifty years, the per capita availability has come down from a high of around 3000 l/day to about 1000 l/day in 2002. By the sheer size of the country, population and climatic heterogeneity, the fresh water withdrawal for various use is the highest in India at around 380 km3/year while for Pakistan it is around 155 km3, Bangladesh around 22 km3 and Sri Lanka around 6 km3. It is expected that in about 30 years, Figure 1a: Per capita water availability in south Asia. India as a whole will come under the grouping of “water Source: ‘Population Action International’, Washington, D.C. stressed” countries (Subramanian, 2000). Pakistan is Report no. 202. 42 V. Subramanian

Table 1: Hydrological data on rivers in South Asia.

River Name Run-Off Area Specific Yield (km3 yr–1) (km2) (mm yr–1) Vaigai 0.7 6348 110 Tamirabarani 0.8 4761 168 Manjira 4.1 21694 189 Sabarmati 4.1 21674 189 Chambal 4.8 23025 208 Indus (India, Pakistan) 73.3 321289 228 Figure 1b: Per capita water availability Gomti 7.4 30437 243 in major metros in India. Cauvery 21.4 87900 243 Sutlej 14.6 57000 256 focus in scientific studies in the sub-continent. Based on Krishna 67.8 258948 262 a very large database developed over the last few decades Tapti 18.4 65145 282 Thungabhadra 9.4 28180 334 for India and Bangladesh coupled with published data Mahi 11.8 34842 339 for other countries in the region, the author has been able Padma to arrive at a few regionalised conclusions with respect (Bangladesh) 350.5 980000 358 to several water quality issues. Yamuna 131.7 366233 360 Subarnareka 10.8 29196 370 Godavari 119.0 312812 380 Major Parameters in Water Quality Narmada 41.3 98796 418 Pranhita 43.0 100000 430 In a vast sub-continental framework, the natural factors Sone 31.8 71200 447 that regulate water quality starts with the nature of surface Ramganga 15.2 32400 469 rocks exposed for interaction with water. While the Mahanadi 66.9 141589 472 geology of the region is very complicated, the lithology Damodar 9.8 20000 490 Ravi 7.7 14442 533 can be simplified as composed of soft rocks/sediments 525.0 861404 609 in the Himalayan and northern plain region while the Hooghly 493.0 750000 657 southern plateau region in India and Sri Lanka is Brahmani 36.2 51822 699 dominated by hard rocks with a thin belt of soft rocks Beas 14.7 20303 724 along the 8000-km coastal belt (Valdiya, 1984). The Ghaghra 94.4 127000 743 Gandak 52.2 64300 812 surface water flow is through a dozen major rivers that Bharatpuzha 5.1 6186 824 includes Indus (India and Pakistan), Ganges (India, Nepal Periyar 4.9 5398 908 and Bangladesh), Brahmaputra (Tibet, India and Kosi 57.2 62000 923 Bangladesh) in the north while the central region is Chalakudi 1.6 1704 939 drained by the Narmada, Tapti, Mahanadi and Sabarmati Kadalundi 1.1 1122 980 Kalinadi 3.7 3750 987 and the southern region by the Godavari, Krishna, Achenkovil 1.5 1484 1011 Cauvery and Periyar (Figure 2). Several small rivers in Jamuna Sri Lanka drain on both sides of the island to the Indian (Bangladesh) 654.5 580000 1128 Ocean. Table 1 summarises the key hydrological features Pennar 67.8 55213 1228 of the surface water in the sub-continent. Mandovi 1.6 1150 1391 Pamba 3.4 2235 1521 Water quality for some of the large rivers at their Manimala 1.6 847 1889 respective river mouth are summarised in Table 2. One Megna of the unifying factors is the excellent relationship (Bangladesh) 151.5 80000 1894 between the major parameters Ca and Mg and the Zuari 1.1 550 2000 alkalinity as indicated in Figure 3. All the rivers, in Kallada 3.4 1699 2001 Chaliyar 5.9 2923 2018 general, show high carbonate alkalinity independent of Muvatupuzha 3.6 1554 2317 local lithology; rock weathering involving atmospheric Brahmaputra CO2 and minerals in different lithology uniformly (India) 537.2 194413 2763 ++ ++ – Other small rivers 162.2 599501 271 releases Ca , Mg and HCO3 to the river water (Berner and Berner, 1996). The values shown in Table 2 reflect India total 1850.0 3288000 563 World total 40856.0 101000000 405 Water Quality in South Asia 43

Table 2: Average chemical composition (ppm) of South Asian Rivers.

River HCO3 Cl SO4 SiO2 Ca Mg Na K TDS Kerala Rivers 12 7 4 9 3 2 5 1 39 Cauvery 135 20 13 23 21 9 43 4 272 Gomti 274 9 15 15 30 19 27 5 394 Krishna 178 38 49 24 29 8 30 2 360 Godavari 105 17 8 10 22 5 12 3 181 Mahanadi 122 23 3 17 24 13 14 8 224 Narmada 225 20 5 9 14 20 27 2 322 Tapti 150 65 1 16 19 22 48 3 322 Indus 64 5 23 5 54 12 10 0.3 173 Brahmaputra 56 11 4 7 14 5 7 3 107 Ganges 128 10 11 18 25 8 11 3 241 Indian Rivers 74 15 13 7 30 7 12 3 159

Figure 2: Location of major rivers in south Asia. 44 V. Subramanian

quality shows enhanced values through major urban centres for a number of key parameters so that by the time the river reaches Kolkata about 2500 km downstream of the originating point, the chemical nature of the water is totally different reflecting both natural weathering and also contribution from anthropogenic input via a very large number of urban and industrial outlets in the mid-stream region. After Farakka, while one arm of the river (called Padma) enters Bangladesh, the other arm (locally named Hooghly) flows through Kolkata to the Bay of . The water quality of the Figure 3: Relationship between dissolved Ca, Mg and alkalinity in rivers of south Asia. Peninsular and river Padma in Bangladesh is relatively better since it is Himalayan rivers are shown in different symbols. diluted by addition of cleaner water from another mighty river Brahmaputra (called Jamuna in Bangladesh) before long term discharge weighted average values for the water the combined river system flows into the Bay of Bengal quality of major rivers in south Asia. The physiography (Ittekkot et al., 1999). and micro-climatic conditions widely vary in the region Dutta and Subramanian (1997) studied the water and often even within a single river system. For example, quality of the combined Ganges- the mighty Ganges has snow covered semi-temperate system in the Bengal basin area both in India and upper reaches in the Himalayas while in the mid- and Bangladesh and concluded that the water chemistry is down-stream reaches, some of its tributaries bring water influenced by rock weathering in the upper reaches and from tropical system weathering soft volcanic rocks atmospheric deposition (monsoon rain) in the lower (Gupta and Subramanian, 1997). Thus, water quality in reaches while in the mid-reaches, human impact is clearly different parts of the rivers varies widely simply due to visible. The atmospheric contribution to the water differences in weathering pattern under local conditions. chemistry of the Himalayan river system and also for Figure 4 illustrates this aspect using Ganges as an Godavari, as an example for the peninsular river system, example. In the upper reaches in the Himalayas, the is given in Table 3. Over the lower part of the Bengal Ganges water shows relatively low levels of various Basin the chemistry of the rain water (Table 3a) is typical solute loads (Sarin et al., 1984; Subramanian, 2000). As for monsoon rain in near coastal regions. The snow over the river flows through the mid-stream alluvial terrain the Himalayas does not seem to be contaminated with with a large number of tributaries such as the Yamuna, respect to the major ions. For ions other than chloride, Ram Ganga, Gomti, Ghagra, Gandak (all flowing from the atmospheric contribution (Table 3b) is over shadowed the Nepal Himalayas) and Sone (flowing from the by weathering and anthropogenic contribution in Vindyan mountains in the south) with diverse lithology locations inland far away from the delta region adjoining (hard rocks to unconsolidated sediments) representing the Bay of Bengal. wider geological age (Precambrian to Recent), the water

Table 3a: Major ion chemistry of rain water in and around Bengal basin (mmol.l)

2+ 2+ –1 –1 –1 2– Stations Ca Mg Na K Cl SO4 Chapainwabganj 11 7 17 21 8 5 (Rajshahi, Bangladesh) Kolkata 99 36 68 9.5 113 36 Kolkata 16 5 37 4 28 8 Kolkata 31 4 36 12 28 25 Mohanbari 4.7 2.5 8.5 6.4 20 6.7 (Brahmaputra Valley) Port Blair, Andaman 17 13 132 8 87 5 Chhoto Snow 6 4 17 7 21 2 Glacier Ice 2.6 1.4 8 3 11 1.8 Godavari Basin 82 53 32 23 200 7 Weighted Average 73 35 56 16 17 18 Water Quality in South Asia 45

Figure 4: Water quality of the Ganges at different locations from near source area to the river mouth in India and Bangladesh. 46 V. Subramanian

Table 3b: Estimated atmospheric contribution to the monsoon solute load of the Ganga- Brahmaputra- system in the Bengal basin (in %)

River Ca Mg Na K Cl SO4 Ganges (Padma) 2 2 4 25 5 4 Ganges (Padma) 1.7 2.2 27 1.3 100 1.6 Brahmaputra (Jamuna) 2 1 6 12.5 62.5 7 Meghna 3 2 10 25 100 29 Godavari 15 24 6 18 43 9 India, Average 9 12 17 31 35 16 Amazon 0.1 1.3 6.9 0.4 17.6 3.6 World Average 6 19 53 27 72 42

estimated to be about one billion litres/day. Even for smaller river, such as Damodar (river of sorrow) flowing through dense industrial belt in the eastern part of the Ganges basin, the effluent output is estimated to be over 50 billion kilolitres/day (Agarwal and Narain, 2000). Hence, either urban area contribution or industrial contribution basically accounts for the rapid decline in the health of most rivers in the region. Even in non- Figure 5: Coliform bacterial counts in the Ganges industrial areas such as near Kota (in the State of river at different locations in India. Rajasthan in India) for the river Chambal (tributary of Source: Agarwal and Narain ( 2001) the river Yamuna flowing into the Ganges), the urban liquid wastewater discharge to the river is about 100 Urban Area Influence million litres/day (Report of the Central Pollution Control Board, 2000). On the other hand, in the southwest part Among the important water quality parameters, coliform of the sub-continent, small rivers draining relatively counts vary erratically in the entire downstream region smaller areas in the western ghat mountain chains, of the Ganges river covering the densely populated directly drain into the Arabian sea but their water regions all along its 2500 km stretch (see for example, chemistry, as indicated in Figure 6, show very little urban Figure 5). It may be mentioned that over 70% of all health influence though the region is one of the most densely problems in south Asia is due to different types of water- populated in south Asia. borne bacterial population (Mahbub ul Haq, 2002). The Indus River also draining the Himalayas and then Further, many reports of different water pollution control flowing through densely populated regions in Pakistan boards in India (data from Compendium of Environ- shows strong influence of various types of human mental Statistics, 1999) indicate that BOD (Biological activities. Tariq et al. (1996) have shown that the river Oxygen Demand) values are in excess of permissible becomes a drain at its mouth near Karachi after receiving levels for drinking water at practically all locations in urban and industrial waste from a number of cities along the sub-continent. The status of BOD in other river the route. Large rivers flowing through populated urban systems in the sub-continent is no better with very high or industrial centres show varying degrees of anthro- values of BOD in excess of 50 mg/l for Indus at Karachi pogenic impact on their water quality. The urban liquid (Tariq et al., 1996) and BOD over 40 mg/l for rivers in and solid waste in several cities are shown in Figure 7 Bangladesh (Shahid, 2000). and it can be seen that urban waste varies from a low of While large rivers such as the Ganges flowing through about 100 million litres/day to a high of over 2000 million densely populated regions show different controlling litres/day (Figure 7a) while for the solid waste, that is factors, smaller rivers also flowing through densely generally four times more than the liquid waste, the populated areas show very little impact. The Ganges numbers vary from 500 to 5000 tonnes/day. For example, flows through one of the densely populated regions and in Delhi, several drains carry a very large amount of the total urban effluents through the major urban areas is industrial loads such as heavy metals Ni, Cr and Hg to Water Quality in South Asia 47

2- 4

-

Figure 6: Water quality of two small rivers in southwest region of the Indian sub-continent. 48 V. Subramanian

levels of mercury in the mobile fraction of sediments at many locations in the Yamuna river basin from the Himalayan catchment to its confluence with the river Ganges 1400 km downstream (Figure 8). Mercury also have been reported in the sediments off the delta region in the Bay of Bengal (Subramanian and Mohanchandran, 1994). Problem of metal pollution is also seen in the coastal waters in major cities such as Mumbai, like Figure 7a: Urban solid and liquid waste discharges many inland waters with varying degree of metal into different rivers in major metros in India. contamination, as indicated in Table 4.

Figure 7b: Levels of heavy metals in waste water Figure 8: Mercury concentrations in sediments in Delhi. of river Yamuna in India.

Table 4: Selected contaminants entering coastal waters of Mumbai through domestic waste water

Contaminant Avg. concen., ppm Load, kg/day Dissolved solids 1800 3.6 × 106 Suspended particulate matter 235 4.7 × 105 Biological Oxygen Demand 280 5.6 × 105 Nitrogen 35 7 × 104 Phosphorus 6 1.2 × 104 Figure 7c: Toxic metals supply by drains Manganese 0.7 1400 to the Yamuna river in Delhi. Iron 2.1 4100 Cobalt 0.03 20 Nickel 0.08 160 Copper 0.1 200 Zinc 2.3 4600 Lead 0.05 100 Source: Zingde (1999).

Quality of Other Water Bodies

Figure 7d: Toxic metals in solid components There are several regions in the sub-continent where the of liquid waste in Delhi. quality of groundwater also has been receiving serious attention. Table 5a summarises the quality of ground- the Yamuna river (see for example, Figure 7b-7d, data water in different aquifer areas in the region. The from Matouri, 2000; Ali and Jain, 2001). Even the levels compositions are widely variable representing different of mercury in many river waters, sediments and soils lithology ranging from soft rock aquifer host rocks in in south Asia has been highlighted in a recent UNEP the eastern parts to hard rock aquifers in the peninsular Report (Global Mercury Assessment Report, 2002). regions. One common factor is the problem of floride Subramanian et al. (2003, in press) have reported high and nitrates in the sub-surface water. While the floride Water Quality in South Asia 49 problem is lithology based, the nitrate problem represents of the sub-continent receive over 4000 million litres/day seepage of agricultural wastewater into the ground, of wastewater from the hinter land and Shivkumar et al. particularly in the Indo-gangetic alluvial terrain where (2001) indicated that aqua culture and other modern the lithology is highly permeable alluvium spread over practices in use to speed up economic uplift of the coastal an area 2000 km long and 1500 km wide with an average population contribute directly to the decline in the water depth of 500 metres (Abrol et al., 2001). In an extensive quality all along the coastal regions. study, Madhavan and Subramanian (2000, 2001) reported The state of water quality in many places in the Indian several groundwater bodies in the region showing large sub-continent is being monitored by several field stations levels of arsenic and also floride, well above WHO of the Central Pollution Control Board and in one of their permissible limits. Several groundwater bodies in urban recent compilation of the data, the health of the water regions are also known to be heavily contaminated with bodies for the most part was found to be not satisfactory heavy metals such as the arsenic and this is illustrated (CPCB web site, 2003). Subramanian (2002) surveyed with example from Chennai as indicated in Table 5b. In the entire region for various types of problems with addition, coastal waters all along the 9000 km coastline respect to water quality and concluded that practically

Table 5a: Chemistry (mg/l) of Groundwater from different parts of India

pH F Cl NO3 HCO3 PO4 SO4 SiO2 Ca Mg Na K Region 7.4 2.3 249 24 426 — 79 12 59 49 187 96 A.P. 7.1 0.4 3 0 68 — 7 — 17 4 4 3 7.4 0.3 138 7 860 — 38 — 55 18 307 4 Bihar 7.6 0.4 571 1 418 0.25 149 34 126 180 446 58 Delhi 7.1 2.4 305 460 730 — 21 — 28 40 400 4 Gujarat 7.1 0.8 280 1 312 — 27 — 88 50 122 3 Karnataka 7.1 0.1 23 4 116 — 11 — 36 7 15 1 Kerala 7.1 0.1 145 1 220 — 70 — 65 27 58 47 Orissa — 2.9 104 17 383 0.007 114 — 62 14 161 — Punjab 7.7 5.6 750 262 1039 — 474 — 68 76 1089 24 Rajasthan 7.3 2.3 338 1 281 — 31 — 56 56 178 1 T.N. 7.3 0.5 28 10 297 — 39 — 62 18 44 12 U.P. 7.2 1.2 8 48 383 — 2 — 92 17 10 4 W.B.

pH F Cl NO3 HCO3 PO4 SO4 SiO2 Ca Mg Na K India 7.4 2.4 235 65 448 0.115 115 26 65 45 268 29 avg. 6.8 0.1 3 0.1 20 0.100 118320.1min. 8.5 12.2 1754 870 3499 0.300 931 49 386 674 1869 676 max. 68 47 73 64 73 9 71 6 73 72 72 67 n

Table 5b: Arsenic and other contaminants in groundwater in Chennai, Tamil Nadu

Range WHO MINAS Element Min. Max. Mean HDL MPL HDL MPL River Ocean As 56 2477 407 50 150 30 150 2 3 Se 12 92 32 0 10 10 10 0.2 0.1 V 56 2192 377 ----12 Cr 5 88 18 75 200 75 200 1 0.2 Fe 91 474 182 500 1000 - - 40 2 Pb 1 25 7 50 - - 5 1 0.03 Cu 24 559 141 50 1500 - 1000 7 0.5 Zn 46 8466 765 - - - 1000 30 2 Cd1325- -10-0.05 Ni 26 85 40 - - - 100 2 0.5 50 V. Subramanian the entire sub-continent suffers from one or other types lakes appear to be highly contaminated and with water of problems as illustrated in Table 6a which may be at a premium in these areas due to diminishing rainfall, because of excess floride due to natural leaching, excess many of the lakes have in fact shrunk substantially in the arsenic due to too much groundwater withdrawal or last few years (Das, 1999). arsenic and other heavy metals contamination due to Similarly, the dissolved phosphorous in many types urban liquid or solid waste discharges and deposition of of water in the entire region is primarily governed by mercury enriched particles onto river systems etc. excess fertiliser run-off from agricultural fields Specific problems with respect to heavy metals in water (Subramanian, 2000; Datta and Subramanian, 1997; Tariq is illustrated with example for many rivers in south Asia et al., 1996). Data given in Table 8 shows that major in Table 6b. The sub-continent has large number of inland water bodies in India are over-saturated with respect to and coastal lakes as well as many small water bodies in Ca-phosphate and under-saturated with respect to Ca- the Himalayas. Table 7 shows example of water quality floride phase, the common contributor being the excess for some of the lakes in the sub-continent. Most of these fertilizer (manufactured from floro-apatite minerals) run

Table 6a: Various nature of problems in water quality in South Asia Water bodies Nature of problem Bengal Basin, India + Bangladesh Arsenic in groundwater Hyderabad, India Metal leakage to sub-surface water Lahore and Hyderabad, Pakistan Industrial waste water into Indus river Delhi, India Drains discharge of metals to Yamuna river Chennai, India Arsenic in groundwater Many locations in India and Sri Lanka Nitrate, fluoride in groundwater Bottled water, India Pesticides Rivers in India Pesticides at high level Lakes in South Asia P & N problem West Coastal water Trace gas emission

Table 6b: Toxic element concentration (µg/l) in various water bodies of South Asia* Location Nature As Cd Co Cr Cu Fe Hg Mn Pb Se Zn Andhra Pradesh Surface Water 23 - - 15 59 100 - - - 10 74 Andhra Pradesh Sub-surface Water 51 - - 5 57 68 - - - 11 117 Indus River Surface Water 1295 14 - 18 26 209 208 209 73 - 62 Bengal Basin Sub-surface Water 130 12286897 - 723 5 12 80 Chennai Sub-surface Water 421 1 4 16 29 474 - 264 4 18 5443 Mumbai Coast Waste water - - 30 - 100 2100 - 700 50 - 2300 Mahanadi River Surface Water 1 0.01 2 10 6 - - 97 3 - 11 Surface Water 3 0.1 5 20 14 - - 181 10 - 24 Baitrani River Surface Water 0.8 0.04 6 26 11 - - 234 5 - 17 Kolleru Lake Surface Water - 4 3 10 70 - 10 10 - 10 *Data collected from different sources listed in the references

Table 7: Major elemental concentration in various lakes in India (Values in ppm, except pH)

Lake pH Cl HCO3 PO4 SO4 SiO2 Ca Mg Na K Udaisagar 9.3 145 232 0.2 93 8 21 34 110 14 Vembanad 6.2 59 3 0.2 75 - 4 18 34 5 Astamudi 7.3 7113 49 0.1 1949 - 100 1167 3451 29 Chilka 7.6 604 90 0.1 104 0.1 24 87 295 17 Dal Lake 8.1 - 17 0.1 0.3 17 0.7 4 1 Nainital 8.1 19 254 90 48 54 12 5 Kolleru 8.3 208 178 3 48 108 124 80 4 Water Quality in South Asia 51

Table 8: Average concentration (ppb) of fluoride, phosphorous and calcium in South Asian water bodies

Name Major lithology Rainfall, mm pH F P-PO4 Ca IAP/K* River Cauvery Granite gneisses 875 7.6 239 50 25714 –2.8 River Tapti Basalt 1250 7.9 204 12 24638 –2.8 River Narmada Basalt 1250 8.2 119 3 26957 –3.2 River Mahanadi Shale-gneisses 1750 7.7 13 2 19563 –5.3 River Godavari Basalt and gneisses 1000 8.6 175 68 20375 –3.4 River Krishna Granite gneisses 875 7.6 324 25 31298 –2.3 River Ganges Recent alluvium 1250 7.7 151 27 31491 –3.2 River Brahmaputra Recent alluvium 2250 7.6 116 22 20997 –3.4 River Megna Recent alluvium 2500 7.5 66 – 6580 –4.4 River Indus Granite 600 7.6 150 49 29058 –2.9 Himalayan rivers Shale-gneisses 1500 7.8 285 67 30738 –3.0 East flowing rivers Granite gneisses 875 7.9 244 45 25754 –3.2 West flowing rivers Basalt 2000 7.5 156 19 13958 –3.7 Major river basin Various lithology - 7.8 271 55 29634 –3.0 Medium river basin Various lithology - 7.6 189 26 10327 –3.8 Minor river basin Various lithology - 7.1 100 14 12781 –4.2 South Asian rivers Various lithology - 7.8 248 49 26026 –3.2 Indian estuaries Coastal alluvium - 7.9 605 381 275997 –1.1 World average Various lithology - 6.1 152 8 15000 –3.2 * –log K = 10.4 for Fluoride. off from agricultural fields. In addition, due to pesticides and insecticides application generally in excess of required quantities, even drinking water shows various pesticides at levels in excess of permissible limits and this point was highlighted recently in public debate about drinking water quality (Figure 9a data from Report of Vellar Tanks Bay of Bay Bengal Hoogly Ganges Yamuna Cauvery Pondichery Arabian Sea

River/Oceans Nanital Lake Tamiraparan

Figure 9b: Dissolved pesticides in various river waters in south Asia. Data from James (2000).

may be noted that the Ganges shows the highest levels of dissolved pesticides (James, 2000).

Factors Influencing Water Quality in South Asia Figure 9a: Pesticides in bottled water marketed in India. Different commercial brands were checked. The water quality in south Asia can be viewed as consisting of several components. Not all of them are CSE, 2003) resulting in the Government of India deciding relevant at all places but example, as mentioned, exists to change specifications for water quality standards and in the region for everyone of such impact as listed below: methodology for analysis by bottled water industry (Times of India, March 15, 2003). Even the river water 1. Natural weathering contribution. Example: upper in the sub-continent shows pesticide levels well above reaches of Brahmaputra, small rivers of southwest the permissible limits, as indicated in Figure 9b and it coast of India. 52 V. Subramanian

2. Natural leaching from specific minerals. Example: Tamaraparani, very large-scale applications of many Floride problem in Ajmer district of Rajasthan in types of pesticides in the agricultural hinterland has India, floride in groundwaters in many other parts resulted in the dissolved pesticides levels showing up in of the sub-continent. surface water (James, 2002). Even in Delhi with the high 3. Urban contamination of groundwater due to growth agricultural base in neighbouring regions as the discharges, seepages etc. Example: arsenic in hinterland, many types of pesticides beyond WHO groundwater in Chennai and Hyderabad, southern permissible limits have been reported even in bottled India; Indus in Pakistan. drinking water (Public Report, Centre for Science and 4. Urban contribution to surface water quality due to Environment, Delhi, February 2003). In a similar vein, direct or un-regulated discharges in many large rivers near the sites of major leather industries in India and passing through populated regions. Example: Delhi Pakistan, such as Chennai in southern India, Karachi in Yamuna river contamination, Karachi (Pakistan)- Pakistan and Kolkata in Eastern India, dissolved Indus river contamination, Dakka (Bangladesh) – chromium is reported to be high in the surface waters water pollution due to waste disposal into Padma- (UNDP, 2003; WHO, 1996). Jamuna river system. Electroplating industries in some locations— 5. Excess groundwater withdrawal and spread of Hyderabad and Delhi—are known to be contributing to contaminants. Example: arsenic problem in the the heavy metal load of the river system (Shivkumar et Bengal Basin area. al., 2001 and Rawat et al., 2001). 6. Atmospheric contribution due to monsoon. Example: Cl and Na in river waters near all the Conclusion coastal regions in India and Bangladesh. 7. Fertiliser run-off from agricultural field. Example: Thus, the water quality scenario in the South Asian region Dissolved phosphorous in surface water in the entire is one of the key components of our environment and sub-continent in all river systems. requires an integrated approach to understand and solve 8. Mining activities impact on water quality. Example: key problems in areas where the social dimensions are River Damodar in eastern India known as the “black larger. Such an approach may involve expertise from river”: or “dead river” due to coal dust and many chemical, physical, biological, microbiological, social other contaminants (Central Pollution Control Board and economic components so that at least the quality Report, 2000); smelter (enrichment of metals from aspects of “water stress” may be addressed satisfactorily primary minerals) activities contributing toxic and as a result making quality water available to all the metals (such as cadmium, mercury and arsenic) to stakeholders in the region. South Asia has example of water and soil in Rajasthan (Madhavan and water contamination from all types of human activities Subramanian, 2001). either directly or indirectly: persistent organic chemicals 9. Seasonal microbiological factors. During monsoon, (POP) such as DDT and pesticides, toxic metals such as many types of coli and other microbes exceed in Hg and As, general contaminants such as P and N in their MPC (most probable counts beyond per- sub-surface water, floride problem as in Rajasthan, salt missible limits) in the entire sub-continent. 70% of water intrusion in coastal regions, excess coliform and health problems due to water-borne bacteria in India, other bacterial population beyond MPN (Most Probable Bangladesh and Pakistan (State of India, WHO web- Number as per EPA definition). The population is thus site, February 13, 2003). vulnerable to all forms of water pollution problems. 10. Salt water intrusion, particularly important in coastal There are many parts of the region that have not been regions. Example: in Chennai in southern India, due adequately studied so far e.g., the mountain watershed to excess withdrawal of groundwater due to paucity regions of Nepal and Bhutan and the snow/glacier bound of surface water availability, salt water intrusion regions of China-India-Pakistan requires serious and in many of the coastal aquifers have been reported international collaborative studies to understand the effect (Ramesh et al., 2001). of snowmelt on water quality and also impact of climate In addition to the above factors, many other locally change factors on glacier melting. Since the South Asian important activities may add to the water quality issues. region has a very large number of high-density population For example, in one of the small southern rivers in India, centres spread over the entire sub-continent, any changes Water Quality in South Asia 53 in the watershed region will have serious consequences Ittekkot, V., Subramanian, V. and S. Annadurai (1999). on water quality and quantity in the entire region. With Biogeochemistry of Rivers in tropical South and South- half the population already on the doors of “water stress” east Asia. SCOPE publication, Hamburg University, condition, any further perturbation will surely aggravate Hamburg, Germany, 240 p. their already stressed existence both with respect to the James, R.A. (2000). Environmental Biogeochemistry of availability and quality of water. Tamiraparani river basin, South India. Ph.D. Thesis submitted to Anna University, Chennai, 257 pp. Acknowledgement Madhavan, N. and V. Subramanian (2000). Sulphide mining as a source of arsenic in the environment. Current Science, Some of the work related to this paper was made possible 78(6): 702-709. through a Fellowship at the Hanse Institute of Advanced Madhavan, N. and V. Subramanian (2001). Fluoride Study, Delmenhorst, Germany. Discussion with experts concentration in river waters of South Asia. 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