Status of pollution in Indian estuaries · Tamil Nadu •Cooum •Ennore Gujarat •Sabarmati – 60 mld •Narmada ... Umra (15.12.2005) Agricultural runoff Fertilizer consumption

Status of

pollution in

Indian estuaries

M. D. Zingde

Sources of pollution

•  Domestic wastewater (Sewage)   Organic matter   Nitrogen & phosphorus   Pathogens, viruses, ….

•  Agricultural runoff   Nitrogen & phosphorus   Pesticides

•  Industrial effluents   Organics (oil &grease, pigments, phenols, organic matter ….)   Heavy metals   SPM (mining, distilleries ….)   Heat

•  Transport   Oil   TBT

Hooghly : Impact of Farakka Barrage

Kolkota

Diamond H

Zone 1

Zone 2

Zone 3

Salinity (ppt) Zon

e Pre-Farakka Post-Farakka

1959-67 1975-1992 1 Trace 2.6 Trace 0.06 2 Trace 23.19 0.02 11.00 3 1.56 32.77 1.45 29.29

Phytoplankton Phytoplankto

n Zone 1 Zone 2 Zone 3

Pre Post

Pre Post

Pre

Post

Species (No) 79 44 67 40 50 33 Freshwater (%)

55 61 37 53 18 Low

Euryhaline (%)

35 39 41 38 40 High

Marine (%) 10 Nil 22 10 42 High

Estuaries, (1996) 710 Sinha et al (2004)

Hooghly : Impact of Farakka Barrage

Post-Farakka fisheries •  Average annual catch increased by 213% •  Marine and neritic species such as Liza parsia,

Eleutheronema tetradactylum, Coila spp, Tenualosa toli, Ilisha elongata and Harpodon nehereus declined / disappeared from Zones 1 &2

•  Purely freshwater species Rita rita, Wallago atu, Mystus aor, Aila coila, Catla catla, Labeo rohita, Macrobrachium rosenbergii appeared in zones 1 &2

•  Annual landings of prime fish hilsa (Tenualosa ilisha) increased sharply

•  Several commercially non-important estuarine and marine species (Chanos chanos, Plotosuscanius, Megalops cyrinoides, Elops saurus etc) significantly declined Sinha et al (2004)

Domestic wastewater

Total sewage generated: 22,900 mld Treatment capacity: 13,500 mld Untreated sewage released to coastal areas : 5062 mld Total P : 12,755 t/y Total N : 82,125 t/y

Maharashtra • Ulhas • Mahim • Thane Creek • West Bengal • Hooghly – 860 mld Kerala • Kochi Backwaters – 260 mld • Ashtamudi estuary Tamil Nadu • Cooum • Ennore Gujarat • Sabarmati – 60 mld • Narmada • Tapi – 90 mld • Ambika Andhra Pradesh • Godavari

1300 mld Maharashtra

Kerala

Gujarat

Orissa

Pondicherry

Untreated sewage (mld) directly released in estuaries / creeks / sea

CPCB Report (2005)

Impacts of sewage High impact

Parameter LT HT DO (mg/l) 0 <3 NO3-N (µM) 0 >10

NO2-N (µM) 0 >10

NH4-N (µM) >20 <5

PO4-P (µM) >8 <5

Sulphides Present

Absent

Pathogens V high V high Macrobenthos

V poor V poor

Examples Inner Ambika (Summer) Inner Ulhas (Dry season) Mahim Cooum

Medium impact Parameter LT HT

DO (mg/l) 1-3 3-6 NO3-N (µM) >20 <10

NO2-N (µM) 5-10 <3

NH4-N (µM) 3-20 <3

PO4-P (µM) >5 <5

Sulphides Absent

Absent

Pathogens V high High Macrobenthos

Rich Rich

Examples Inner Tapi estuary (Dry season) Outer Ulhas (Dry season) Inner Thane Creek Kochi Backwaters (Dry season)

Most estuaries do not meet Water Quality Criteria for Fecal Coliform (100/100 ml) set by CPCB

Tapi estuary

Randher barage

Sewagw outfall (90 mld)

Umra

Hazira

Magdalla

Temporal and spatial variations (Tapi)

APN Project Report (2004) 153 Baperdekar, Ph D Thesis (2004)

Umra (15.12.2005) (COMAPS)

Mouth

Sewage

Tapi estuary

R² = 0.63

0 2 4 6 8

10 12 14

0 1 2 3 4

Salin

ity (p

su)

DO (ml/l)

R² = 0.71

0 2 4 6 8

10 12 14

0 5 10 15

Salin

ity (p

su)

Nitrate-N (µM)

R² = 0.82

0

2

4

6

8

10

12

14

0 10 20 30 40 50

Salin

ity (p

su)

Ammonium-N (µM)

0 1 2 3 4 5 6 7 8 9

10

0 10 20 30 40 50

Nitr

ite-N

(µM

)

Ammonium-N (µM)

R2=0.55

R² = 0.63

0

2

4

6

8

10

12

14

0 10 20 30 40 50

Nitr

ate-

N (µ

M)

Ammonium-N (µM)

R² = 0.46

0

2

4

6

8

10

12

14

0 2 4 6 8 10

Salin

ity (p

su)

Nitrite-N (µM)

Umra (15.12.2005)

Agricultural runoff Fertilizer

consumption Year Million t

1951-52 0.07 1971-72 2.7 1991-92 12.7 1999-00 18.0 2008-09 24.9

Fertilizer application 5 -163 kg/ha Total cropped area 196 million ha Assumed fertilizer application

125 kg/ha

N:P:K (National average) 7 : 2.7 : 1 Fertilizer loss through runoff

0.5 - 20 (av: 10) kg/ha

Estimated annual loss 1.96 million t N loss 1.3 million t P loss 0.4 million t

Agricultural Statistics, 2010 J Hydrology, 293 (2004), 375

Pesticide production (2007-08)

85,000 t

Application (Agri) 0.5 kg/ha DDT use since 1985

350,000 t

DDT (Present production)

7000 t

BHC banned 1997 PoPs banned 2004

Env Int. 31 (2005) 503

Nutrients Godavari estuary

Parameter Discharge (m3/s)

>2000 <200 Nil Salinity 0.07 9.96 22.29 DIN (µM) 38.9 18.0 9.0 DIP (µM) 4.98 1.23 0.46 SiO4 (µM) 63.5 37.8 18.6

Chl-a (mg/m3)

1.42 4.68 2.98

NCP (mM C/m2/d) -0.97 15.71 26.75

Variations in Chl a and NCP and high N:P ratios during dry period probably due to anthropogenic P and N ECSC. 85 (2009) 515

Parameter Season

Pre-M M Post-M Salinity 23.52 11.2 13.66 DIN (µM) 13.0 21.82 14.72 DIP (µM) 1.51 2.09 1.64 SiO4 (µM) 65.48 85.43 77.75

GPP ((mM C/m2/d)

439 328 382

Nitrate and phosphate levels comparable during period 1975 and 2001 J Mar Syst. 62 (2006) 9

Hooghly estuary

Pesticides Area Pesticide Componen

t Findings Reference

Hooghly estuary(Lower)

HCHs, DDTs, HCB, Endosulfan

Sediments Generally low with elevated levels near outfalls

Env Int. 29 (2003), 587; Env Int. 29 (2004) 523.

West coast estuaries

HCHs, DDTs, Aldrine, Endrin

Sediments Low but elevated as compared to open sea

Wat Res. 31 (1997) 195

Vellar estuary DDTs, BHcs, Endosulfan

Plankton Low Bul Plankton Soc Jap. 37 (1990) 59

Kochi Backwaters

Endosulfan, Malathion

Water, sediment

Low Wat Res. 33 (1999) 109

West & East Coast

HCSs, DDTs Sediments; Fishes

Lower than reported elsewhere

Chemosphere, 44 (2001) 301

Trace metals in sediments Estuary Enrichment Reference

Hooghly Cr, Ni, Cu, Zn, Cd, Pb, Hg, As

Env Int. 30 (2004) 1089

Baitarani Cr, Co, Cu, Ni, As J Hydrology, 193 (1997) 258

Brahmani Cr, Co, Cu, Ni, As J Hydrology, 193 (1997) 258

Mahanadi Cr, Co, Cu, Ni, As J Hydrology, 193 (1997) 258

Chilka Cr, Mn, pb J Coast Res. (2010) 860

Rushikulya Hg Sci Total Env. 96 (1990) 281

Ennore Cr, Cu, Cd Env Geo. 56 (2008) 207

Kochi Backwaters

Ni, Cu, Zn, Cd, Pb Int J Sci Tech. 6 (2009) 225

Mandovi-Zuari TBT; As Env Mon As. 165 (2010) 643; Fate Env As. (2003)

Amba Hg IJMS. 38 (2009) 89

Thane Creek Cr, Ni, Cu, Zn, Pb, Cd, Hg Chem Geo. 90 (1991)203

Ulhas Cr, Ni, Cu, Zn, Pb, Cd, Hg Chem Geo. 90 (1991)203

Tapi Cr, Zn, Pb Geochem J. 40 (2006) 522

Mindhola Cu, Zn, Pb MPB. 19 (1988) 540

Uncertainties in assessment of metal pollution

Metal Sediment (µg/g) Krishna Narmada

Al - 4.0-9.6 Cr 13-315 58-370 Mn 140-2330 748-1736 Fe 5400-5750

0 43000-6300

0 Co 15-83 44-62 Ni 5-117 19-49 Cu 15-83 51-183 Zn 3-72 115-148 Hg - 0.16-0.2

Muller’s equation

Igeo = log2 Cn/1.5 Bn Igeo = Geoaccumulation Index Cn = measured concentration Bn = Background

EF = (Cn/Al) / (Bn/Al) EF = Enrichment Factor

General assessment of estuarine pollution

•  Contamination of estuaries by untreated domestic wastewater is widespread, however, in absence of time-series studies the responses of native flora and fauna to modified environment are unclear.

•  Agricultural runoff contributes to high nutrient loads in estuaries. Their impacts on estuarine ecology – particularly responses of plankton and the influence on the food chain needs to be investigated.

•  Estuaries are generally free from contamination by chlorinated pesticides. India being signatory to Stockholm Convention on Persistent Organic Pollutants, their levels in estuaries is no more a concern.

•  Sediments in some estuaries stretches are enriched in anthropogenic trace metals. However literature, though scanty, indicates their general non-availability for biological uptake.

•  Information is largely lacking for several chemical pollutants such as PAHs, phenols, dyes and pigments etc.