Contamination and Ecological Risk Assessment of Heavy Metal in the Sediment of Turag River, Bangladesh: An Index Analysis Approach

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1 Journal o Water Resource and Protecton, 2013, 5, Publshed Onlne February 2013 ( ontamnaton and Ecologcal Rsk Assessment o Heavy Metal n the Sedment o Turag Rver, Bangladesh: An Index Analyss Approach Zoynab Banu 1,2, Md. Sharul Alam howdhury 3, Md. Delwar Hossan 4, Ken ch Nakagam 5 1 Gas Transmsson ompany Ltd. (GTL), Under the Mnstry o Power, Energy and Mneral Resources, Government o Bangladesh, Bangladesh 2 Department o Envronmental Engneerng, Bangladesh Unversty o Engneerng and Technology (BUET), Dhaka, Bangladesh 3 DM o Dhaka Water Supply Sector Development Project (DWSSDP), Dhaka Water Supply and Sewerage Authorty (DWASA) & World Bank Scholar, Graduate School o Polcy Scence, Rtsumekan Unversty, Kyoto, Japan 4 Department o Envronmental Engneerng, Faculty o vl Engneerng, Bangladesh Unversty o Engneerng and Technology (BUET), Dhaka, Bangladesh 5 Graduate School o Polcy Scence, Rtsumekan enter or Sustanablty Scence, Rtsumekan Unversty, Kyoto, Japan Emal: zoynab.sac@gaml.com, sharcda@gmal.com, delwar@ce.buet.ac.bd, nakagam@sps.rtsume.ac.jp Receved November 18, 2012; revsed December 21, 2012; accepted December 31, 2012 ABSTRAT Encroachment, dsposal o untreated domestc and ndustral wastewater and dumpng o sold wastes have degraded the overall qualty o the rver Turag, whch s located n Dhaka the aptal ty o Bangladesh. The present study nvestgated the extent o polluton o sedments o ths rver and analyzed the regonal varablty or the concentratons o r, Pb, Zn, u and d all o concern because o ther potental toxcty, usng atomc absorpton spectrophotometer. As per US EPA sedment qualty gudelne, metal concentratons ranged between d: , r: , u: , Pb: , and Zn: mg/kg n the Turag rver sedments. r, u, Zn belongs to moderately to hghly polluted, Pb and d belongs to not polluted or Turag rver. The heavy metals contamnaton n the sedments were also evaluated by applyng Index o geo-accumulaton (Igeo), contamnaton actor (), polluton load ndex (PLI) etc. Toxcty characterstcs leachng procedure (TLP) test (US EPA 1311) or sedment samples have been perormed also or metals (Pb, d, r, u and Zn) to determne the readly toxcty level o heavy metals. Seve analyss o sedment perormed n ths study to determne the physcal characterstc o sedment samples. The metal concentratons are well below the regulated level as per US EPA. Ths ndex can be complemented wth the contamnaton ndex, whch allows more ste-specc and accurate normaton on contamnant levels. I the am o work on contamnaton evaluaton s to assess the overall contamnaton o a study area, the ndces are hghly approprate. Keywords: Heavy Metal; TLP Test; Sedment; Geo-Accumulaton Index; Ecologcal Rsk Index; ontamnaton Factor; Turag Rver etc. 1. Introducton The Rver Turag runnng by the sde o the Dhaka ty, the captal o Bangladesh, s one o the most polluted rvers n Bangladesh. Many ndustres have set up n and around the Dhaka ty durng last decade, and the number o new ndustres are contnually ncreasng [1]. The rver Turag have been steadly experencng complcated problems lke polluton and encroachment that have almost suocated these valuable lelnes o the cty The hghest polluton ponts o the Turag Rver nclude the Burganga Thrd Brdge area at Bashla and the Tong Brdge area. At these two ponts, the rver water s ptchblack wth the worst o smell and can be used or hardly any purpose. The other extreme polluton spot s near the Tong Brdge that derves massve pollutant loadng rom the Tong Industral Area. Ths ndustral area possesses about 29 heavy ndustres. Ths cluster o ndustres o the captal cty generates a lot o eluents daly, whch contan lots o heavy metal. Polluton o the natural envronment by heavy metals s a unversal problem because these metals are ndestructble and most o them have toxc eects on lvng organsms, when permssble concentraton levels are exceeded. Heavy metals requently reported n lterature wth regards to potental hazards and occurrences n contamnated sols are d, r, Pb, Zn, Fe and u [2]. Vehcle exhausts, as well as several ndustral actvtes emt these heavy metals so that opyrght 2013 ScRes.

2 240 sols, plants and even resdents along roads wth heavy trac loads are subjected to ncreasng levels o contamnaton wth heavy metals [3]. Heavy metals contamnaton n aquatc envronment s o crtcal concern, due to toxcty o metals and accumulaton n aquatc habtats. Trace metals n contrast to most pollutants, not bodegradable, and they undergo a global ecologcal cycle n whch natural water are the man pathways. O the chemcal pollutants, heavy metal beng non-bodegradeable, they can concentrated along the ood chan, producng ther toxc eect at ponts ater ar removed rom the source o polluton [4]. Exposure to heavy metals has lnked to several human dseases such as development retardaton or malormaton, Kdney damage, ancer, aborton, eect on ntellgence and behavor, and even death n some cases o exposure to very hgh concentraton. The symptoms o toxc heavy metal posonng and the symptoms o autsm, PDD, Aspergers, & ADD/ ADHD are very smlar. Toxc metals could be the cause o those symptoms. Memory loss, ncreased allergc reactons, hgh blood pressure, depresson, mood swngs, rrtablty, poor concentraton, aggressve behavor, sleep dsabltes, atgue, speech dsorders, hgh blood pressure, cholesterol, trglycerdes, vascular occluson, neuropathy, autommune dseases, and chronc atgue are just some o the many condtons resultng rom exposure to toxns [3,4]. Heavy metals poson us by dsruptng our cellular enzymes, whch run on nutrtonal mnerals such as magnesum, znc, and selenum. The heavy metals most oten mplcated n human posonng are lead, mercury, arsenc, and cadmum. Some heavy metals, such as znc, copper, chromum, ron, and manganese, are requred by the body n small amounts, but these same elements can be toxc n larger quanttes. Toxc heavy metals may lead to a declne n the mental, cogntve, and physcal health o the ndvdual. Objectves The overall objectve o the present study s to assess the heavy metal contamnaton n rver sedments o some polluted rvers. Specc objectves o ths study nclude: To assess the level o heavy metal concentratons n the sedment, ts spatal dstrbuton and compare t wth the USEPA qualty gudelne. Applcaton o advanced statstcal technques such as prncpal component analyss, cluster analyss and correlaton matrx n order to nvestgate the complex dynamcs o pollutants, source o heavy metal concentraton n the sedments and relatonshps. To select derent polluton ndces to assess heavy metal contamnaton. To assess the ecologcal rsk due to sedment contamnaton. 2. Method and Materals Sedments sample were collected rom ve stes along the Turag Rver as showng n Fgure 1, Lattude and Longtude or each ste were llustrated n Table 1. The sedment samples were drectly collected rom the Turag Rver durng the dredgng o Turag bed sludge. The samples were carred by polythene bag. Ater collecton, some porton o sedment samples were dred n a vacuum oven at 105 untl constant weght, lghtly ground n an agate mortar or homogenzaton and prepared or analyss o heavy metal and some porton o samples were prepared or seve analyss, mosture content and organc content test. For heavy metal test, 5 gm o dred sample was dgested wth acd and prepared 500 ml soluton. Fnally, ve heavy metals (Pb, d, r, u, and Zn) concentraton were determned n the envronmental engneerng laboratory, BUET by usng atomc absorpton spectrophotometer (AAS). To determne the physcal characterstcs o sedment, mosture content, organc matter content and seve analyss test were also perormed. Toxcty characterstcs leachng procedure (TLP) test or sedment samples were perormed or ve heavy metals (Pb, d, r, u and Zn) to determned the readly toxcty level o heavy metals. Heavy metal concentraton or the ne porton o sedment samples (sample whch passng through # 200 seve) were also perormed n ths study. The selected sample drawng ponts o the Turag Rver ncludes the ponts near Iztema Feld, Tong Brdge, Gabtal Brdge and Snnr Tek BIWTA Landng Staton. Analyzng the DoE provded water qualty data o 5 years ( ) (Table 2), the ollowng temporal pattern o the Turag Rver Polluton has been ound (Fgure 2). Due to rapd and unplanned urbanzaton and ndustralzaton the Dhaka cty s surroundng rvers, ncludng the Turag have gradually experenced undue and unbearable pressure to ther very exstence. The man reason behnd ths spatal polluton pattern n the Turag wthn above mentoned area s that huge load o untreated toxc lqud chemcal waste s drectly dumped nto the rver rom Hazarbagh tanneres through the Bashla Khal at the downstream and rom the Tong Industral Area at Table 1. Locaton o sedment sample collecton. Staton No. Name o Locaton Longtude Lattute 1 Tong Brdge 90 24'4.04"E 23 52'54.30"N 2 World Estema Feld 90 23'37.98"E 23 52'47.64"N 3 Kamarpara Brdge 90 23'23.61"E 23 53'27.88"N 4 Taltola Brdge 90 22'40.97"E 23 53'54.98"N 5 Ashula Ber Bandh 90 21'37.41"E 23 53'33.34"N opyrght 2013 ScRes.

3 241 Fgure 1. Map o perpheral rvers around Dhaka cty. opyrght 2013 ScRes.

4 242 Fgure 2. Locaton o coordnates o derent stes n Turag rver. Table 2. Varaton o water qualty parameters n Turag rver durng [5]. Parameter Unt ph mg/l E,, hlorde,, 2 34 Turbdty,, TS,, TDS,, DO,, 6 0 BOD,, OD,, Tong Brdge and Iztema Feld area. 3. Result and Dscusson 3.1. Heavy Metal oncentratons The total metal concentratons or each samplng ste ound n sedments n ths study are shown n Table 3. Metal contents were rangng over ollowng ntervals: Pb: mg/kg; d: mg/kg; r: mg/kg; u: mg/kg; Zn: mg/kg dry weghts. Mean concentraton o the metals were: Pb: mg/kg; d: 0.28 mg/kg; r: mg/kg; u: mg/kg; Zn: mg/kg dry weghts, allowng to arrange the metals rom hgher to lower mean Table 3. oncentraton o heavy metals (mg/kg dry weght) o sedments o Turag rver. Locaton Lead (Pb) admum (d) hromum (r) opper (u) Znc (Zn) T T T T T Mean Max Mn SD content n ths area as: Zn > u > r > Pb > d. Pearson s correlaton coecent matrx among the selected heavy metals o Turag rver sedments s presented n Table 4. Sgncant correlatons between the contamnants o r and Zn (r = 0.71), Pb and u (r = 0.50), Zn and u (r = 0.34) could ndcate the same or smlar source nput Physcal haracterstc o Sedment (Seve Analyss) Seve analyss result o sedment sample s presented n the Table 5. Average n all stes, 1.75% materals retan on #4 and above seve and 25.34% materals passng opyrght 2013 ScRes.

5 243 Table 4. orrelaton matrx between heavy metals n sedment samples rom Turag rver. Pb d r u Zn Pb 1 d r u Zn Table 5. Seve analyss result o the sedment sample o the Turag rver. Seve Sze (ASTM) Staton 1 Staton 2 Staton 3 Staton 4 Staton 5 % Materals % Materals % Materals % Materals % Materals Retans (gms) Retans (gms) Retans (gms) Retans (gms) Retans (gms) No No No No PAN TOTAL % oarse % Medum % Fne through the #200 seve whereas 72.90% materals retan on #8 to #200 seves that ndcate the sedment sze o the Burganga Rver ranges over medum to ne sze and t contans a sgncant amount o ne partcle. The average mosture content and organc matter content o the sedment sample are 82.26% and 7.12% respectvely. A relatonshp s ound between the mosture content and organc matter content. Hgher mosture content n the sedment sample shows the hgher organc matter content. There s another relatonshp ound n ths study, the stes whch contan hgher organc matter shows hgher heavy metal concentraton. For example, Staton No. 4 and 5 whch contan hgher organc matter (10.14% and 12.2% respectvely) showed hgher heavy metal content (Fgures 3-6 are the most sedment contamnaton scenaro o Turag rver, Dhaka). 4. Assessment o Heavy Metal ontamnaton 4.1. Assessment Accordng to Unted States Envronmental Protecton Agency (USEPA) Protecton Agency (USEPA) The chemcal contamnatons n the sedments were evaluated by comparson wth the sedment qualty gudelne proposed by USEPA. These crtera are shown n Table 6. Present study shows that all the stes are not polluted or Pb, Moderately Polluted or u, r and Zn whle or r, stes 3 s Hghly polluted. For d, all the stes are ranges over not polluted to moderately polluted condton Assessment Accordng to Geo-Accumulaton Index (Igeo) A common crteron to evaluate the heavy metal polluton n sedments s the geo-accumulaton ndex. Geoaccumulaton ndex proposed by Muller [6] to determne metals contamnaton n sedments, by comparng current concentratons wth pre-ndustral levels and can be calculated usng the ollowng ormula: (1) n Igeo log2 1.5B n where, n s the concentraton o element n and B n s the geochemcal background value [In ths study, consder B n = world surace rock average gven by Martn and Meybeck [7]]. The actor 1.5 s ncorporated n the relatonshp to account or possble varaton n back- opyrght 2013 ScRes.

6 244 Fgure 3. Textle wastewater dscharge n Turag rver. Fgure 6. Ptch black water dscharges rom textle dyeng unts n low deep canal that lnk wth Turag rver. Table 6. USEPA Gudelnes or Sedments (Mg/Kg dry weghts). Metal Not polluted Moderately polluted Heavly polluted Present study Pb < > d. > r < > u < > Zn < > Fgure 4. Industral wastewater dscharge n Turag rver. Fgure 5. Ptch black water o Turag rver, the west o Tong Brdge, Dhaka, Bangladesh. ground data due to lthogenc eect. The geo-accumulaton ndex (Igeo) scale conssts o seven grades (0-6) rangng rom unpolluted to hghly pollute (shown n Table 7). Accordng to the Muller scale, the calculated results o I geo values shown n Table Assessment Accordng to ontamnaton Factor The contamnaton actor and degree o contamnaton are used to determne the contamnaton status o the sedment n the present study. ontamnaton actor s calculated accordng to D.. Thomlson, D. J. Wlson,. R. Harrs, D. W. Jerey [4]. metal F (2) background In ths study world surace rock average proposed by Martn and Meybeck [7] s consdered as background concentraton. F < 1: low contamnaton actor; 1 F < 3: moderate contamnaton actor; 3 = F < 6: consderable contamnaton actor; F = 6: very hgh contamnaton actor. opyrght 2013 ScRes.

7 245 Table 7. MULLER S classcaton or the geo-accumulaton. Igeo Value lass Sedment Qualty 0 0 Unpolluted From unpolluted to moderately polluted Moderately polluted From moderately to strongly polluted Strongly polluted From strongly to extremely polluted >6 6 Extremely polluted Table 8. Geo-accumulaton ndex (I geo ) at derent samplng staton n Turag rver by Muller (1979). Locaton Pb d r u Zn T T T T T F 1n PLI F F F (3) n I PLI < 1 ndcates no polluton. PLI > 1 ndcates polluted sedment. The degree o contamnaton (d) s dened as the sum o all contamnaton actors (see Table 9). The deteroratng condton o the Turag/Burganga Rver n the md-1990s stmulated the polluton Hotspots o Dhaka (see Fgure 7). Most o the eort ocused on publc awareness, processons, montorng o the Dhaka canal and rver system, and destructon o buldngs that encroached on the Turag Rver [5]. Table 10 shows contamnaton actor, polluton load ndex and degree o contamnaton at derent locatons along Turag rver. All locatons are moderately contamnated wth lead. T-1, T-2 and T-3 are less contamnated, T-4 moderately contamnated and T-5 consderably contamnated wth cadmum. All locatons have low contamnaton due to chromum and moderate contamnaton or copper. T-1 and T-3 are moderately contamnated; T-2, T-4 and T-5 are less contamnated wth znc. As per polluton load ndex, T-4 and T-5 locatons sedment are polluted and T-1, T-2 and T-3 are not polluted. Hghest polluton load ndex value s observed at T-5 and mnmum at T-3. Degree o contamnaton values range rom 4.89 to Maxmum value o degree o contamnaton was ound at T-5 and mnmum at T-2. As per degree o contamnaton t s ound that T-4 and T-5 are the loca- Table 9. Termnologes used to descrbe the contamnaton actor. F d Descrpton F < 1 d < 6 Low degree o contamnaton 1 < F < 3 6 d < 12 Moderate degree o contamnaton 3 < F < 6 12 d < 24 onsderable degree o contamnaton F > 6 d 24 Very hgh degree o contamnaton tons o moderate contamnaton and T-1, T-2 and T-3 are the locatons o low contamnaton Assessment Accordng to Polluton Load Index (PLI): Ecologcal Rsk Index For each contamnant the PLI s calculated usng the ormula proposed by Wlson and Jerey [8]: B PLI ant log10 1 (4) T B B s the baselne value not contamnated; T the threshold, mnmum concentratons assocated wth degradaton or changes n the qualty o the estuarne system. Wlson and Jerey [8] dene B and T or the derent contamnants; the concentraton o the pollutant. For each place the PLI calculaton takes nto account all the n contamnants: n 1n PLI PLI PLI PLI PLI (5) PLI vares rom 10 (unpolluted) to 0 (hghly polluted). Ths ndex allows the comparson between several estuarne systems. It has been appled successully n European estuares. Values o baselne and threshold not dened locally or each coastal zone analyzed and not recently revsed. Polluton load ndex at derent locatons o Turag rver s shown n Table 11. For Turag rver, all locatons are moderately polluted as per polluton load ndex proposed by Wlson and Jerey [8] Assessment Accordng to Potental Ecologcal Rsk Index In 1980, Lars Hakanson reported an ecologcal rsk ndex or aquatc polluton control; thereore, Hakanson s method has been oten used n ecologcal rsk assessment as a dagnostc tool to penetrate one o many possble avenues towards a potental ecologcal rsk ndex,.e., to sort out whch dranage area, reservor, and substances should be gven specal attenton [9]. The ndex s calculated as the ollowng equatons: D (6) R opyrght 2013 ScRes.

8 246 Table 10. Polluton load ndex and degree o contamnaton o Turag rver sedments. Sample Locaton ontamnaton actor o sngle metal Pb d r u Zn PLI Degree o contamnaton by Tomlnson et al. (1980) T Unpolluted 5.96 Low T Unpolluted 4.89 Low T Unpolluted 5.22 Low T Polluted 6.04 Moderate T Polluted 8.58 Moderate Table 11. Polluton load ndex or Turag rver. Locaton Polluton load ndex o sngle metal Pb d r u Zn ombned PLI by Wlson and Jerey (1987) T Polluted T Polluted T Polluted T Polluted T Polluted H m 1 E T m RI E 1 E T (7) (8) (9) (10) From the Table 12, n whch, s the polluton coecent o sngle metal; D s the measured concentraton o sample; R s the background concentraton o sedments; H s the polluted coecent o many metals; E s the potental ecologcal rsk actor o sngle metal; T s the bologcal toxcty actor o derent metals; and RI s the potental ecologcal rsk ndex o many metals. From Table 13, t can be seen that the order o potental ecologcal rsk actor o heavy metals n sedments o the Turag rver s d > u > Pb > Zn > r; d s the most mportant one and ts rsk actor s upto the apprecable grade. The results ndcate that the range o d polluton n the Turag rver s low to apprecable. Other heavy metals (Zn, r, u and u) have low potental ecologcal rsk. The ndex range o potental ecologcal rsk s rom to , and the average ndex o potental ecologcal rsk actors (RI) s Turag rver has a low to moderate potental ecologcal rsk due to heavy metal contamnaton [5]. Table 12. Evaluated parameters or ecologcal rsk ndex calculaton. Parameter d r u Pb Zn Pre-ndustral background values (Martn and Meybeck, 1979), Toxc Response Factor, R T Assessment Accordng to Integrated Polluton Index (PIN Index) A new polluton ndex, PIN ndex (a background enrchment ndex), was adapted rom PI, and based on the Portuguese legslaton on the classcaton o dredged materals: PIN m 1 W B 2 1 (11) where W s the class o the contamnant consderng the degree o contamnaton (rom 1 to n = 5); the concentraton o the contamnant ; B 1 the concentraton o contamnant n lass 1 (baselne value clean sedments). Accordng to the legslaton mentoned above, the sedments (and the ndex) can be classed nto ve categores (Table 14), rom clean to hghly contamnated sedments. PIN ndex values were normalzed n a nomnal scale rom 1 to 5, accordng to the threshold classcaton values. Each ndex threshold was calculated usng opyrght 2013 ScRes.

9 247 the W and values or the correspondng class lass 1 (clean): [0-7]; lass 2 (trace contamnated): [7-95.1]; lass 3 (lghtly contamnated): [ ]; lass 4 (contamnated): [ ]; lass 5 (hghly contamnated): [ ]. PIN Index at derent samplng locatons along Turag rver s shown n Table 15. Accordng to PIN Index, T-1, T-3 and T-5 sedments are n trace contamnated condton whle and T-2 and T-4 are clean condton Assessment Accordng to Toxcty haracterstcs Leachng Procedure (TLP) Toxcty haracterstcs Leachng Procedure (TLP) s a very mportant tool or assessng readly contamnated heavy metal or sedment samples [10]. In ths study, heavy metal concentratons rom leachate o Turag Rver Sedments were tested n the laboratory and polluton levels o leachate were assessed wth comparson o EPA standard. Results o the TLP test are presented n the Table 16. For all the stes, concentratons o heavy metal n leachate are not exceeded the permssble EPA standard. That ndcate regardng the readly toxcty polluton by heavy metal, Turag Rver Sedment condton s not the severe state. 5. oncluson Geo-accumulaton ndex, contamnaton actor and degree o contamnaton, Metal polluton ndex, Enrchment actor and Multvarate statstcal analyss were successully appled or the assessment o heavy metal contamnaton o Turag rver sedments. The sedment sze o the Turag rver ranges over medum to ne and t also contans a sgncant amount o ne partcles. Metal concentratons ranged between d: , r: , u: , Pb: , and Zn: Table 13. Ecologcal rsk ndex or Turag rver. Locaton Zn d r u Pb T T T T T RI Grade Hakanson (1980) T Low T Low T Low T Low T Moderate Table 14. lasscaton o dredge materal n coastal zones accordng to DR, lasses/contamnants (mg/kg) d Pb Zn u As r Hg lass 1: lean dredged materal <1 <50 <100 <35 <20 <50 <0.5 lass 2: trace contamnated dredged materal lass 3: lghtly contamnated dredged materal lass 4: Lghtly contamnated dredged materal lass 5: Hghly contamnated dredged materal >10 >1000 >5000 >500 >500 >1000 >10 Table 15. PIN ndex at derent samplng staton n Turag rver. Locaton Pb d r u Zn W W W W W PIN DR, 1995 T Trace T lean T Trace T lean T Trace opyrght 2013 ScRes.

10 248 Table 16. TLP test result (mg/l) or the sedment sample o the Turag rver [11]. Locaton Pb d r u Zn T T T T T Mean Max Mn SD mg/kg n the Turag rver sedments. As per US EPA sedment qualty gudelne d belongs to not polluted. r, u, Zn belongs to moderately to hghly polluted, Pb & d belongs to not polluted or Turag rver. For all stes, concentratons o heavy metal n the leachate are not exceeded the permssble US EPA standard. That ndcate regardng the readly toxcty polluton by heavy metal, Turag rver sedment condton s not the severe state. Sgncant correlaton ound between the contamnants o r and Zn (r = 0.71), Pb and u (r = 0.50), Zn and u (r = 0.34) n Pearson s correlaton or the heavy metals o Turag rver. Ths concludes that those contamnants may have same or smlar source nput. Polluton load ndex (PLI) ranges rom n Turag rvers. Accordng to geo-accumulaton ndex, Turag rver s unpolluted wth r & Zn. unpolluted to moderately polluted wth Pb, d and u. Accordng to PIN Index, all locatons o Turag rver sedments are clean to trace contamnated. Turag rver has a low to moderate potental ecologcal rsk due to heavy metal contamnaton. Degree o contamnaton o sedments o Turag rver s low to moderate. Envronment, Dhaka, [2] O. Akoto, J. H. Ephram and G. Darko, Heavy Metal Polluton n Surace Sols n the Vcnty o Abundant Raway Servcng Workshop n Kumas, Ghana, Internatonal Journal o Envronmental Research, Vol. 2, No. 4, 2008, pp [3] H. Ghreat and N. Yusu, Assessng Mn, Fe, u, Zn and d Polluton n Bottom Sedments o Wad Al-Arab Dam, Jordan, hemosphere, Vol. 65, No. 11, 2006, pp do: /j.chemosphere [4] D.. Thomlson, D. J. Wlson,. R. Harrs and D. W. Jerey, Problem n Heavy Metals n Estuares and the Formaton o Polluton Index, Helgol. Wss. Meeresunlter, Vol. 33, No. 1-4, 1980, pp [5] P. K. Saha and M. D. Hossan, Geochemcal and Ecotoxcal Approach or Evaluaton o Heavy Metal Polluton n the Burganga Rver Sedment, Proceedngs o Bangladesh Geotechncal onerence, [6] G. Muller, Index o Geoaccumulaton n Sedments o the Rhne Rver, Journal o Geology, Vol. 2, No. 3, 1979, pp [7] J. M. Martn and M. Meybeck, Elemental Mass Balance o Materals arred by Major World Rvers, Marne hemstry, Vol. 7, No. 3, 1979, pp do: / (79) [8] J. Wlson, Evaluaton o Estuarne Qualty Status at System Level wth the Bologcal Qualty Index and the Polluton Load Index (PLI), Bology and Envronment B, Vol. 103, 1987, pp [9] L. Hakanson, Ecologcal Rsk Index or Aquatc Polluton ontrol, a Sedmentologcal Approach, Water Research, Vol. 14, No. 8, 1980, pp do: / (80) [10] P. K. Saha and M. D. Hossan, Assessment o Heavy Metal ontamnaton and Sedment Qualty n the Burganga Rver, Bangladesh, 2nd Internatonal onerence on Envronmental Scence and Technology, IPBEE, Sngapore, February [11] G. Muller, The Heavy Metal Polluton o the Sedments o Neckars and Its Trbutary: A stocktakng, hem. Zet., Vol. 105, 1981, pp REFERENES [1] DoE, Water Qualty Data o Rvers Burganga, Meghna, Balu, Shtalakhya, Jamuna ( ), Department o opyrght 2013 ScRes.