Toxicity Characteristic Leaching Procedure data for metal contaminated soil treated with silica treatments or an orthophosphate-silica mix treatment.

Brief description

TCLP data was collected in 2013 as part of a pilot scale batch study which assessed the potential of silica treatments and an orthophosphate-silica mix treatment for the remediation of metal contaminated soil in Antarctica.

The contaminated soil used in this study was sourced in January 2008 from a stockpile at the Thala Valley waste disposal site at Casey Station, East Antarctica (Stark et al., 2006). Concentrations of leachable Cu, Zn, As and Pb in the soil averaged 1.3 plus or minus 1.0, 2.6 plus or minus 1.8, less than 0.01 and 3.0 plus or minus 3 .8 mg/L, respectively (Thums et al., 2010). Three treatments and one untreated control (Table 1) were applied in-duplicate at room temperature to columns loaded with 1 kg of Thala Valley soil sieved to less than 2 mm using a stainless steel mesh. The silica treatments were applied by mixing calcium carbonate powder with soil, followed by the application of sodium metasilicate dissolved in Type I (ASTM 2011) reagent water (Milli-Q). The phosphate-silica treatment contained Triple Super Phosphate (TSP), calcined magnesia ('Qmag'), calcium carbonate applied as powder, followed by the application of a sodium metasilicate solution (Table 1).

The experiment was performed at room temperature, with each column leached daily with 100 ml of Milli-Q water for 10 days. Leachate samples were collected and stored unacidified (to prevent formation of a silica gel) for later analysis, if required. Six months after application of the silica treatments, two soil samples were obtained from each column. These 16 samples, along with 21 samples of untreated soil collected at the start of the experiment, were extracted according to the Toxicity Characteristic Leaching Procedure (TCLP; US EPA Method 1311; US EPA 1992) and analysed at the Australian Antarctic Division for metals using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES).

Data available: Published paper including summary data and detailed explanation of experiment (only available to AAD staff) as well as an excel file containing the raw experimental data.

Some further notes about the spreadsheet:

1. All of the values are leachable concentrations of the metals listed in row 3, in mg/L.
2. The numbers for the elements listed in row 3 are provided immediately below them for each experimental treatment (e.g. SME C4. A).
3. The acronyms refer to the identity of the four treatments assessed in the experiment which are provided within the table in the paper you attached that Damian provided earlier. In the paper these appear as Control (SME C1 A, A2, B and B2), Silica 1 (SME C2 A, A2,B and B2), Silica 2 (SME C3 A, A2, B, B2) and Orthophosphate-silica (SME C4 A, A2, B and B2).