Trace organics in sediments inTrace organics in sediments in the lower stretch of Ganges

t d th iestuary and their ecotoxicological significanceecotoxicological significance

Dr. Santosh Kumar Sarkar

*Department of Marine Science, University of Calcutta, 35 B.C. Road, Kolkata-700019,India

Key words: persistent organic pollutants, K y wor s p rs st nt organ c po utants, sediments, Ganga estuary; Sunderban Mangrove

wetland.

The Ganga (Hugli) estuary comprises a complex interplay of theBhagirathi-Hugli river system and its numerous tributaries.

This is well-mixed estuary due to intense semidiurnal tide and waveaction with a macro tidal setting and is a typical example of tide-action with a macro tidal setting and is a typical example of tidedominated sink for many classes of anthropogenic contaminants.

Differential discharges of untreated/semi treated effluents originatingfrom industrial agricultural and aquacultural sources along with domesticfrom industrial, agricultural and aquacultural sources along with domesticsewage, fishing and boating activities. Rapid economic developmentsalong the course of Hugli River have put tremendous pressure on thelocal environmentlocal environment.

It is densely populated, low-lying and highly vulnerable coastalenvironment where silting of rivers has become a common problem.

WHY SEDIMENTS for Trace organics?

Marine sediments act as one of the MOST IMPORTANT SINKfor lipophilic contaminantsp p

•From an analytical point of view it is more convenient to carry out the chemical measurements in sediments than in biota or water

•POP concentrations in sediments is normally found higher th tthan water

•For biota, it is necessary to clean up the lipids as well as also to determine the age sex etcalso to determine the age, sex etc.

•For water samples, a large volume of water is needed, also the extraction procedure of POPs from water is much morethe extraction procedure of POPs from water is much more complicated than sediments

Objectives:

• To get a baseline data on spatial distribution of• To get a baseline data on spatial distribution of POP contamination in surface sediment samples

• To evaluate the geochemical factors affecting g gspatial distribution of POPs

• To assess the possible ecological risk based on sediment quality criteria

Persistent Organic Pollutants (POPs)Persistent Organic Pollutants (POPs)

• HCH (Hexachlorocyclobenzene) and isomersHCH (Hexachlorocyclobenzene) and isomers (HCHs)

• DDT (Dichlorodiphenyl trichloro ethane) and its metabolites (DDTs)( )

• Congeners of polychlorinated biphenyls Co ge e s o po yc o ated b p e y s(PCBs) and

• PAH (Polycyclic Aromatic Hydrocarbon).

Processes affecting distribution of POPs

Physical process include

• Diffusion

• Advection

• Sedimentation

Ch i l P i l dChemical Processes include

• Flocculation

• Adsorption & Desorption• Adsorption & Desorption

• Dissolution

• Oxidation & Reduction

• Precipitation

Biological processes include

Bioturbation and Accumulation

Nature of Stresses in IndianNature of Stresses in Indian Major Rivers

• Over-fishing• Siltation• Industrial Pollution• Domestic Sewageg• Water Extraction• Dams and BarriagesDams and Barriages

Site Description:Site Description:

• Sampling was done from seven sites along h f G the course of Ganges estuary

• All studied stations belong to different tidal environments different wave energy tidal environments, different wave energy fluxes and distances from the sea ( Bay of Bengal) and overall diverse human ginterference with a variable degree of exposure to POP contamination.

MethodologySediment samples were collected using hand corers.

Dried in oven at 400 C, ground and passed through 63 μm sieve.through 63 μm sieve.

• Sediment samples were analysed for• Sediment samples were analysed for Organic Carbon, pH, and other physico-chemical parameters using standardchemical parameters using standard methods.

For all the POPs Gas Chromatography Trace GC 2000 i d ith PTV i j t l d ith2000 equipped with a PTV injector coupled with a Polaris Q Ion Trap mass spectrometer, using an AS 2000 auto sampler. For quality control nd quality assurance, a procedural blank was run in parallel with every batch of samples using anhydrous sodium sulphate and then extractedusing anhydrous sodium sulphate and then extracted in a manner identical to that of samples

Sediment Quality Characteristics reveal f ll i f tfollowing features

• pH ranges between slightly acidic to basic (6.5 to p g g y (8.5), acidic nature was partly due to oxidation of FeS2 and FeS to H2SO4 and partly resulted from the decomposition of mangrove litter and hydrolysis of p g y ytannin from mangrove plants releasing various kinds of organic acids.

• The Organic carbon ranges 0.16-0.66% might be dueThe Organic carbon ranges 0.16 0.66% might be due to marine sedimentation and high microbial degradation.

• Variable admixture of sand silt and clay Clay• Variable admixture of sand, silt and clay. Clay fractions dominated in the low energy zone and clear sand and silt dominate in the depositional areas.

Organochlorine pesticidesOrganochlorine pesticides

• OCs are organic compounds of g panthropogenic origin, resist photolytic, chemical and biological degradation.Ch t i d b l t l bilit hi h• Characterized by low water solubility, high lipid solubility, semi volatile- enabling them to move long distance in the atmosphere.to move long distance in the atmosphere.

• Major fractions of ocs released world wide-known to orginate from Asian region.

• Maximum level of OCs is related with high organic carbon concentration in sediments

• ∑HCHs range between 0.05 to 12.4 ng/g ∑ g g gdry weight.

• HCB concentration range 0.05 to 1.39HCB concentration range 0.05 to 1.39 ng/g dry weight.

• ∑DDTs range from 0 05 to 11 47 ng/g dry• ∑DDTs range from 0.05 to 11.47 ng/g dry weight - ER-L values for total DDT is 1 58 ng/g dry wtDDT is 1.58 ng/g dry wt.

Distribution of HCH in sediments

1. Concentration of 4 important metabolites of HCHs reveal a heterogenicnature of distribution. Composition of HCH isomers, beta- and gamma-HCH shared the dominant part of total HCH than alpha- and delta- HCH.

2. This may be related to bio-isomerization of HCH during the process oft t d t t ti i thi t i ttransport and transportation in this estuarine ecosystem.

3 Alpha HCH has relative low values because high vapor pressure and3. Alpha - HCH has relative low values because high vapor pressure andHenry’s law constant and therefore readily lost

4. Ratio of alpha to gamma isomer (α/γ ratios) observed low. This low α/γHCH ratio in the sediment samples implies the use of lindane in theregion. This might be due to microbial degradation.g g g

Distribution of DDT in sediments

1. DDTs were detected in all sediment samples but the contribution ofindividual metabolites showed differences.

2. Among the metabolites of DDT, pp'-DDT and op'-DDT were found to be muchmore significant than other metabolites DDE and DDD. The occurrence ofDDT isomers are predominant in the following order: pp’ DDT> pp’DDD>DDT isomers are predominant in the following order: pp’ DDT> pp’DDD>pp’DDE> op’DDT>op’DDD>op’DDE. The dominance of DDTs in thesediment was also reported by Pandit et al 2002, from the coastal marineenvironment of Mumbai, west part of India. This may be attributed to theslow degradation of DDTs or recent input of DDTs in this environment(Travers et al. 1999,Yuan et al. 2001).

3. The ratio of concentrations of pp'-DDT to that of ∑ DDT (0.36-0.75) showed adefinite indication of recent use of the DDT.

4. Hugli River passes through relatively dense industrial and residentialareas where pesticides are sprayed during the public health campaignagainst malaria and also for other purposes. The relative concentration ofthe parent DDT compared to its biological metabolites, DDD and DDE, canbe used as indicative indices for assessing the possible pollution sources.be used as indicative indices for assessing the possible pollution sources.

5. High percentage composition of op’-DDT and pp’-DDT with respect tot t l DDT l l ill t t th t DDT h t b di t d t itotal DDT clearly illustrates that DDT usage has not been eradicated yet inthe country and there might be new input of DDT to the coastal estuary.India ranked the biggest consumer and manufacturer of HCH and DDT in theworld (Mehrotra, 1993) as these are cheap as well as effective (Baskin, 2003).( , ) p ( , )

6. HCHs were lower than DDTs. This may be due to differences inphysicochemical and biological properties with HCHs having higher waterphysicochemical and biological properties, with HCHs having higher watersolubility, vapor pressure and biodegradability and lower lipophilicity andparticle affinity as compared to DDTs (Loganathan and Kannan, 1994).

Results of Factor Analysis (after Varimax Rotation) considering sediment quality parameters and HCH isomers and DDT

metabolitesVariable Factor 1 Factor 2 Factor 3 Factor 4

% OC -0.039 0.152 0.076 -0.855

% sand -0.38 -0.538 -0.208 0.652

% silt 0.179 0.72 -0.024 -0.269

% clay 0.404 0.174 0.324 -0.722

α-HCH 0.551 0.225 -0.124 -0.157

β-HCH 0.881 0.173 0.097 0.009

γ-HCH 0.864 0.120 0.031 -0.165

δ-HCH 0.757 0.188 0.426 -0.037

op-DDE 0.280 0.193 0.723 -0.174

pp-DDE 0.136 0.017 0.876 -0.214

op-DDD 0.357 0.707 0.015 -0.17

pp-DDD 0.218 0.848 0.273 -0.089

op-DDT -0.016 0.747 0.524 -0.039

pp-DDT -0.124 0.136 0.704 -0.013

% variance 21 6 20 2 17 8 13 7% variance 21.6 20.2 17.8 13.7

% cumulative variance 21.6 41.8 59.6 73.3

Status of major organochlorine contaminants in relevance with sedimentcontaminants in relevance with sediment

quality criteria

DDT metabolites ER-L*

% above ERL ER-M**

% above ERM TEL*** PEL****

% above PEL

pp-DDT 1 7.14 7 2.38 1.19 4.76 2.38

pp-DDD 2 0 20 0 1.22 0 0

pp-DDE 2.2 2.38 27 0 2.07 2.38 0

ΣDDT 0.5 64.28 6 2.38 2.26 21.43 2.38

HCH 0 0 0 0 0 32 66 67 40 48γ-HCH 0 0 0 0 0.32 66.67 40.48

*ERL- Effects Range Low, ERM**- Effects Range Median,

TEL***- Threshold Effects Level, PEL****- Probable Effects Level

Bombay Duck collected from Sunderban region

A carnivorous marine speciesca o ous a e spec es

PCBsPCBs

• Key representative of industrial POPsKey representative of industrial POPs• Synthetic organic compounds

D i d f hl i ti f bi h l• Derived from chlorination of biphenyls• Upto 209 congeners can be generated.• Very persistent in the environment• Now disseminated worldwideNow disseminated worldwide.

Distribution and Potential sources of PCBs :Distribution and Potential sources of PCBs :

• Tetra, penta, hexa and hepta chlorinated isomers are the predominant homologues in the sediments which might be contrib ted from the commercial mi t res sed incontributed from the commercial mixtures used in transformers, electric equipments etc.

• Intense shipping activity, agricultural runoffs, chemical spill, discharge of untreated sewage, diesel-powered electrical generators, garbage incinerators, atmospheric deposition and dumping of toxic and industrial wastes from its surroundingdumping of toxic and industrial wastes from its surrounding land.

• Predominance of highly chlorinated congeners (CB 138, 153, 149 101)149 and 101) persistent in the environment because they are less volatile and non degradable compared to lower chlorinated congeners.

• Dominant PCB congeners include the following sequence:PCB138>PCB153>PCB149>PCB101>PCB118>PCB141>PCB151.

• Mean PCB value ranges from 0.00 to 2.88 ng/g dry weight – much lower than the ER-L value (22.7 ng/g)

• There exists an erratic pattern of distribution of different PCB congeners.

Profile of seven dominant PCB congeners of the seven sampling sites

90%100%

70%80%90%

151

50%60%70%

118141101

20%30%40%

101149153138

0%10%20% 138

S1 S2 S3 S4 S5 S6 S7

Common features of PAHsCommon features of PAHs

• SemivolatileSemivolatile• Bioaccumulative• Persistent and toxicPersistent and toxic• PAHs –contains two or more fused benzene

rings ubiquitous and constitute a major group rings, ubiquitous and constitute a major group of environmental contaminants.

• Two types of anthropogenic sources: w typ f anthr p g n c urc Petrogenic and pyrogenic.

Distribution of PAHs

• Mean Σ22PAH concentration ranged from 153 to 3242 ng g-1 dry wt showing seaward increase of high molecular PAHs ERL values for total PAH 4022 ng/gPAHs – ERL values for total PAH 4022 ng/g.

• Perylene was dominant (~ 50% of total PAHs), may be due to frequent input of soil materials due to strong rainfall in this tropical climatic zone.

• About 80% of ΣPAHs were high molecular weight PAHs, as Perylene (11 26%) Benzo(a)Pyrene (2 32%) andas Perylene (11.26%), Benzo(a)Pyrene (2.32%) and Benzo(g,h,i)perylene (6.84%).

• Carcinogenic compounds like BaP, BkF and BbF were g pmoderately high and compounds like DBA and InP were low in majority of the cases

• PAH diagnostic ratios revealed PAHs in the sediments• PAH diagnostic ratios revealed PAHs in the sediments are of pyrolytic origin.

Standard pollution criteria of PAH components for di t t i ( / )sediment matrix(ng/g)

Compound ERL ERM-----------------------------------------------------------------------------------------

Naphthalene 140 2100Acenapthylene 44 640Acenapthylene 44 640Acenaphthene 16 500Fluorene 19 540Ph th 240 1500Phenenthrene 240 1500Anthracene 853 1100Fluoranthene 600 5100

Pyrene 665 2600Benzo[a]anthracene 261 1600

Compound ERL ERM

------------------------------------------------------------------------

Chrysene 384 2800Benzo[a]pyrene 430 1600Diabenzo[a,h] anthracene 63.4 260

Total 4000 44 792Total 4000 44.792

Characteristic values of selected molecular ratios for pyrolytic and petrogenic origins ofratios for pyrolytic and petrogenic origins of

PAHs

Molecular Ratio Pyrolytic origin Petrogenic origin-----------------------------------------------------------------------Phe/Ant <10 >15Chr/BaA <1 >1Chr/BaA <1 >1Flu/Pyr >1 <1Flu/(Flu+Pyr) >0.5 <0.5( y )LMW/HMW Low High

S i l i i tMeretrix meretrix, Family Veneridae Sanguinolaria acuminataFamily Psammobiidae

Pelecyora trigona, Family VeneridaeAnadara granosa Family Arcidae

Concentration of PAH congeners in Sanguinolariaacuminata (expressed in ng/g dry wt.) collected from

G SitGangasagar Site

1600Si h

1000

1200

1400

Podium

Add. Muscle

Siphon

400

600

800

Gill

Mantle

Vis. Mass

0

200

Nap Acy Ace Flu Phe Ant Flr Pyr BaA Chr BbF BkF BaP DahABghiP Ind

Shell

Assessment of sediment toxicity based on C i i PAHCarcinogenic PAH

(CPAH)TEQcarc = Σ ( C o X TEF carc)TEQcarc = Σi ( Ci

o X TEFicarc)

• The toxic equivalency factors (TEFs) used to quantify the carcinogenicity of other PAHsquantify the carcinogenicity of other PAHs.

• Benzo(a)pyrene is the most toxic PAH congener.F ll d b BAA BbF BkF I [1 2 3 d] DBA• Followed by BAA, BbF, BkF, In[1,2,3 cd]py, DBA and Cry.Maximum TEQ value of 283 ng/g recorded at St Lot• Maximum TEQ value of 283 ng/g recorded at St Lot 8-cleraly reveals high risk of toxicity to the inhabiting biota in the sediments.inhabiting biota in the sediments.

Contribution of 14 dominant congeners of PAH , 1= Flu, 2=Phe, 3=Ant, 4=Fluor, 5=Pyr, 6= BAA, 7= Chr, 8= BbF, 9=BkF, 10=BAP,

11=Per, 12=In(1,2,3-cd)pyr, 13= DBA & 14= B(g,h,i)per

12(g, , )p 234567789101112121314

Comparison of HCHs, DDTs and PCBs (ng/g) in surface sediments from other stations

Locations PCBs DDTs HCHs References

Hong kong, PRCChinese river/estuaries

Victoria Harbour, Hong KongXi H b PRC

0.48-97.90.05-20.03.2-27

0 05 7 2

0.27-14.80.1-711.4-30

4 5 311

0.1-16.70.2-101BDL - 2.3

0 14 1 12

Richardson and Zheng(1999)Hong et al. (1999), Wu et al. (1999), Yuan et al (2001)Connell et al. (1998)H t l (1995)Xiamen Harbour, PRC

Manukkau Harbour, New ZealandAlexandria Harbour, EgyptPearl River Estuary PRC

0.05-7.20.5-14.2

0.9-1211--

4.5-3111.20-2.3

<0.25-8851 38-25 4

0.14-1.120.1-2.0

0.25-6.0BDL-2.33 7-13

Hong et al. (1995)Fox et al (1988)

Assem O. Barakat et al. (2002)Hong et al (1995)Chen et al (1986)Pearl River Estuary, PRC

Juilong river estuary, PRCMediterraneanWu-Shi estuary, TaiwanNorthern coast, Vietnam

------

1.38-25.48.7-690.18

BDL-11.46.2-10.4

3.7-13--1.2-33.70.02-4.550.086-

Chen et al. (1986)Burns and Villeneuve, 1987Ruey-An Doong et al. (2002)Nhan et al. (1999)Khim et al. (2001)Guruge and Tanabe, (2001)

Ulsan Bay, KoreaWest coast of Sri LankaArabian Sea, India

--

0.02-41.90.09-1.61.47-25.2

0.330.85-7.870.008-0.02

g ( )

Sarkar et al. (1997)

Comparison of PAHs (μg/g) in surficial sediments from other stations

Location Total PAHs

ReferencesPAHs (μg/g)

Santos harbour ,Brazil Cananeia mangrove region Brazil

0.08-42.39nd

Nishigima (1999)Nishigima (1999)Cananeia mangrove region,Brazil

Santos-industrial region,BrazilGulf Region- oil refineries, KuwaitTampa Bay, Florida (EUA)Yuandang dumping and garbage

ndnd1.3-1750.2-4.33 6 61

Nishigima (1999)Bicego (1988)Fowler et al. (1993)Sherblom et al. (1995)Hong et al (1995)Yuandang-dumping and garbage

regions,ChinaVictoria Harbour ,ChinaCampeche Bank ,Gulf of MexicoSao Sebastiao Brazil

3.6-61

1.2-14ndnd

Hong et al. (1995)Hong et al ( 1995)Gonzalez et al. (1992)Zanardi (1996)Al Saad and Al TimariSao Sebastiao , Brazil

Northern Arabian countriesNortheastern coast of India

ndnd0.025-1.097

Al-Saad and Al-Timari (1993)Present study

Bioturbation: disturbance and stabilizationBioturbation: disturbance and stabilization• A process relating to burrowing and feeding activities of the infauna

(Polychaete, bivalve, crab) –continually disturbs and rework soft ( y ) ysediments.

• Stabilize the sediment by secreting quantities of mucopolysaccharides that glue the sediment particles together.

• Sediment destabilization mainly caused by deposit feeders which browse, manipulate, sort and process sediment particles. Large deposit feeders such as Diapatra cuprea act like conveyer beltsdeposit feeders, such as Diapatra cuprea, act like conveyer belts, ingesting particles from many centimeter below the surface, passing them through their guts and depositing them as faeces on sediment surface.

Polybrominated diphenyl ethers (PBDE )(PBDEs)

• Synthetic compounds commercially used as flame t d t i l t i i t l ti t tilretardants in electric equipments, plastics, textiles,

building materials, vehicles and aircraft.

• Highly resistant towards acids, bases, heat, light, reducing and oxidizing compounds Reach the environment through leaching and volatization

• Associated with endocrine disruption,(interrupt physiological balance as it behaves like an

d i h ) d ti /d l t lendocrine hormone), reproductive/developmental toxicity (neurotoxic and carcinogenic) similar to PCBs

Distribution of PBDE in Sundarban W tl dWetland

• Non-homogeneous contamination of the wetland with PBDE ranging from 0.08 to 29.03 ng g-1.

• General decreasing order: PBDE 47>99>100>154, similar to the distribution pattern worldwide.

• No uniform temporal trend of PBDE levels was• No uniform temporal trend of PBDE levels was recorded due to particular hydrological characteristics of the wetland.

• Wastes from megacity Calcutta and improper discharges of electric and electronic equipments are the potential sources of PBDE contaminationthe potential sources of PBDE contamination

0-4

4-8

12-16

8-12

m

16-20

12 16c

24 29

20-24

0 5 10 15 20 25 30 -1

24-29

ng g-1

S7 S6 S5 S4 S3 S2 S1

50

r2 = 0.0400; r = -0.1999, p = 0.2043

40

30

atio

n

20

conc

entra

10

0

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

OC%

-10

25

20

15

g-1

10

ng

5

S1 S2 S3

0

S2 S3 S4 S5 S6 S7

100%

80%

60%

153154

40%

99100

20%

40%4728

0%

20%

0%Bromkal S1 S2 S3 S4 S5 S6 S7

CONCLUSIONS AND RECOMANDATION:

1. Data reveal that the Ganges estuary contribute significantlytowards the transport of pollutants and the deterioration of sedimentquality and is closely related to malfunctioning of wastewaterquality and is closely related to malfunctioning of wastewatertreatment facilities, poor compliance of environmental law and lackof environmental planning and coordination.

2. Coastal areas of West Bengal are in a stage of rapid developmentand new mining, dredging and chemical activities are beingincorporated As a result degradation of organic complexes areincorporated. As a result, degradation of organic complexes areexpected and the biota might be exposed to chronic contaminationresulting public health and economical hazards.

3. Long-term ecosystem research and monitoring (LERM) areneeded to provide measures of baseline conditions and fori f i d i i t t d i t linforming decisions on ecosystem management and environmentalpolicy formulation.

Future PlanFuture Plan

• Multi-component monitoring to elucidateMulti component monitoring to elucidate behavior and fate of POPs and to assess the current status of these contaminantsthe current status of these contaminants.

AcknowledgementAcknowledgement

• Dr. Andrea Binelli, University of Milan, ItalyDr. Andrea Binelli, University of Milan, Italy for analyzing the organic contaminants in

the sedimentsthe sediments