Use of Selective Sequential Extraction for the Remediation of Contaminated Sediments

2008 ◽  
pp. 208-208-16 ◽  
Author(s):  
CN Mulligan ◽  
BD Azma
Keyword(s):  
Sequential Extraction ◽  
Contaminated Sediments ◽  
Selective Sequential Extraction

scholarly journals Distribution and partitioning of heavy metals in estuarine sediment cores and implications for the use of sediment quality standards

2002 ◽  
Vol 6 (6) ◽  
pp. 989-998 ◽  
Author(s):  
K. L. Spencer ◽  
C. L. MacLeod
Keyword(s):  
Sequential Extraction ◽  
Surface Sediments ◽  
Sediment Cores ◽  
Sediment Quality ◽  
Contaminated Sediments ◽  
Estuarine Sediments ◽  
Surface Zone ◽  
Metal Concentrations ◽  
Ecotoxicological Risk ◽  
Total Metal

Abstract. Total metal concentrations in surface sediments and historically contaminated sediments were determined in sediment cores collected from three estuaries (Thames, Medway and Blackwater) in south-east England. The partitioning behaviour of metals in these sediments was also determined using a sequential extraction scheme. These data were then compared with sediment quality values (SQVs) to determine the potential ecotoxicological risk to sediment dwelling organisms. When total metal concentrations in surface sediments are examined, no risk to biota in any of the estuaries is indicated. However, when historically contaminated sediments at depth are also considered, risks to biota are apparent and are greatest for the Thames, followed by the Medway and then the Blackwater. This suggests that regulatory authorities should examine vertical metal profiles, particularly in estuaries that are experiencing low sediment accumulation rates where historically contaminated sediments are in the shallow sub-surface zone and where erosion or dredging activities may take place. When metal partitioning characteristics are also considered, the risk to biota is comparable for the Medway and the Blackwater with the potentially bioavailable fraction presenting no ecotoxicological risk. Conversely, over 70% of metals are labile in the Thames Estuary sediments and toxic effects are probable. This suggests that the application of SQVs using total sediment metal concentrations may over- or under-estimate the risk to biota in geochemically dissimilar estuarine sediments. Keywords: sediment quality values, estuarine sediments, metal contamination, partitioning, sequential extraction

Effect of Pb and Cd on Cu adsorption by sand–bentonite liners

2005 ◽  
Vol 32 (1) ◽  
pp. 241-249 ◽  
Author(s):  
Saleh Kaoser ◽  
Suzelle Barrington ◽  
Maria Elektorowicz ◽  
Li Wang
Keyword(s):  
Heavy Metal ◽  
Sequential Extraction ◽  
Metal Cations ◽  
Pressure Head ◽  
Breakthrough Curves ◽  
Metal Adsorption ◽  
Liner Material ◽  
Selective Sequential Extraction ◽  
Total Metal ◽  
Sequential Extraction Analysis

The mobility of Cu alone and in the presence of Cd (compatible) and Pb (incompatible) was studied using laboratory columns packed with a 95 wt.% sand and 5 wt.% bentonite mixture. The liner material was subjected to one of four heavy metal solutions using a pressure head of 7 kPa: 2.0 cmol(+) Cu/L solution; 1.0 cmol(+) Cu and 1.0 cmol(+) Cd/L solution for a total of 2.0 cmol(+)/L solution; and 1.0 cmol(+) Cu and 1.0 cmol(+) Pb/L solution for a total of 2.0 cmol(+)/L solution. The effluents and the liner samples were analyzed for Cu, Pb, and Cd. The breakthrough curves indicated that Cd was the most mobile of the metal cations, whereas Pb was the least. Total metal adsorption was greatest for Cu with Pb, followed by that of Cu with Cd, and then that of Cu alone, showing that Cu is compatible with Cd but not Pb. The selective sequential extraction analysis indicated that most of the Cu was precipitated by the carbonate and hydroxide fractions.Key words: Cd, Pb, Cu, sand–bentonite liners, adsorption, leaching.

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