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Post depositional memory record of mercury in sediment near effluent disposal site of a chlor-alkali plant in Thane Creek-Mumbai Harbour, India

DRS at CSIR-National Institute of Oceanography

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Title Post depositional memory record of mercury in sediment near effluent disposal site of a chlor-alkali plant in Thane Creek-Mumbai Harbour, India
 
Creator Ram, A.
Rokade, M.A.
Zingde, M.D.
Borole, D.V.
 
Subject waste disposal
anthropogenic factors
industrial wastes
effluents
 
Description A mercury–cell chlor-alkali plant operating at Airoli (eastern bank of Thane Creek) for 40 years, caused widespread contamination of the surrounding environment. Untreated wastewater from the plant was discharged to Thane Creek for several years. Thane Creek joins to Ulhas Estuary, an impacted estuary by mercury (Hg) released by several industries including two chlor-alkali industries by a narrow arm and opens to Arabian Sea through Mumbai Harbour. In order to understand historical record of anthropogenic Hg and its association to Al, Fe and total organic carbon (TOC), estimation of Hg, Al, Fe and TOC was made in surface sediments and cores from Thane Creek-Mumbai Harbour (Bay) and the adjacent coastal area. Though 70 % of the plant has been changed to membrane-cell based technology, surficial sediment in the vicinity of effluent release contain high concentration (upto 1.19 mu g g sup(-1) dry. wt.) of Hg as compared to its background value (0.10 mu g g sup(-1) d. w.). The contaminated creek sediments are prone to current-driven resuspension and are acting as a strong source of Hg to the sediment of coastal region. Several rocks and sediments from the catchment area were analyzed to find out natural background of Hg. Lithogenic and anthropogenic Hg buried in marine sediments is quantified based on normalization with Al, Fe and TOC and inter-comparisons of results indicate comparable values obtained by using Al and Fe while discernible deviations are found when calculated by using TOC. The Hg profile in core from the effluent release site for which sedimentation rate has been established, is discussed in terms of progressive removal of Hg from the effluent after mid-1970s and partial changeover of the manufacturing process from Hg cell to membrane cell production subsequent to 1992. Based on reported sedimentation rate in the locality, maximum concentration (49.19 mu g g-1 d. w.) of Hg represents the year 1967, when the chlor-alkali plant started discharging its untreated effluent to the creek. Results indicate that more than 80% of Hg settles in the vicinity of its discharge and once deposited in the sediment, it is not affected to any substantial degree by diagenesis
 
Date 2009-12-22T05:04:48Z
2009-12-22T05:04:48Z
2009
 
Type Journal Article
 
Identifier Environmental Technology, vol.30(8); 765-783
no
http://drs.nio.org/drs/handle/2264/3510
 
Language en
 
Rights © 2007 Taylor & Francis; "Environmental Technology," is available online at http://www.informaworld.com/ with open URL of artilce : http://www.informaworld.com/openurl?genre=article&issn=1479-487X&volume=30&spage=765
 
Publisher Taylor & Francis