EAST TRINITY PROJECT (SOIL SAMPLING)
Sampling and Field Analysis: Southern Cross GeoScience (N.J. Ward and T. Shepherd)
Laboratory Analysis: Southern Cross GeoScience (M. Bush, D.M. Fyfe, C. Maher and N.J. Ward) and
Environmental Analysis Laboratory (EAL) at Southern Cross University
The Excel spreadsheet contains: (1) Soil analytical data, (2) Soil descriptions, and (3) Pore water analytical
data.
Google Earth file contain the sampling locations.
Field Sampling of Soils
Soil sampling was undertaken at five locations at the East Trinity site between 16th and 18th September 2013.
Soil profiles had previously been collected and analysed at or close to (i.e. within 10 m) these sites (alternative
IDs used for these sites are presented in Table 1).
Table 1. GPS co-ordinates of soil sampling sites.
Site (ID)
Site 1 (R8/ETA215)
Site 2 (ETA211)
Site 3 (ETA101 & R3/ETA193)
Site 4 (R2/ETA130)
Site 5 (R1/ETA69)
GPS Co-ordinates
Zone Easting, Northing
55K 0372485, 8126445
55K 0371310, 8126912
55K 0372464, 8126745
55K 0372669, 8127100
55K 0372606, 8127320
Triplicate intact soil profiles were collected from each of site to a depth of 1.2 m. Soil samples were collected
from a total of 14 sampling depths (i.e. 0-5 cm, 5-10 cm, 10-15 cm, 15-20 cm, then every 10 cm to 1.2 m) using
a range of implements (i.e. spades, and augers). At each location soil pits were dug using a spade to
approximately 0.2 m, and then a gouge auger or Russian D-section auger was used to obtain soil samples
below the base of the pit down to 1.2 m.
The soil field pH and redox potential (Eh) were determined on the triplicate samples using calibrated
electrodes linked to a TPS WP-80 meter; Eh measurements are presented versus the standard hydrogen
electrode.
Soil samples were stored in sealed 50 mL centrifuge tubes. Each centrifuge tube was filled to the top,
capped and each cap was wrapped in Parafilm to minimise the potential for sulfide oxidation. The soil
samples were transported in cold iceboxes and were stored refrigerated on return to the Southern Cross
GeoScience laboratory.
Photographs of the five sampling sites are presented in Figures 1 to 5.
Figure 1. Soil sampling site 1 at East Trinity (September 2013).
Figure 2. Soil sampling site 2 at East Trinity (September 2013).
Figure 3. Soil sampling site 3 at East Trinity (September 2013).
Figure 4. Soil sampling site 4 at East Trinity (September 2013).
Figure 5. Soil sampling site 5 at East Trinity (September 2013).
Laboratory Analysis Methods
Soil Analyses
The parameters measured on the soils included:
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Moisture content
Reduced inorganic sulfur (RIS) content (including AVS, S(0) and pyrite)
Titratable actual acidity (TAA)
Total carbon and nitrogen
Total metal(loid) content
The moisture content was determined by weight loss due to drying at 105 ºC; Sediments for further analysis
(with the exception of sediments analysed for RIS and iron fractionation) were oven-dried at 80ºC and sieved
(< 2 mm) prior to being ring mill ground.
The acid volatile sulfide (AVS), elemental sulfur (S(0)) and pyritic sulfur fractions were determined using a
sequential extraction procedure on frozen sub-samples. The AVS fraction was initially extracted via a cold
diffusion procedure, with the use of ascorbic acid to prevent interferences from ferric iron (Fe (III)) (Burton et
al. 2007). The solid phase S(0) fraction was extracted using methanol as a solvent and quantified by highperformance liquid chromatography (HPLC) (McGuire and Hamers 2000). The remaining RIS fraction (i.e.
pyritic sulfur) was determined using the chromium reduction analysis method of Burton et al. (2008).
The potassium chloride (KCl) extractable pH (pH KCl) was measured in a 1:40 1.0 M KCl extract (Method Code
23A), and the titratable actual acidity (TAA) (i.e. sum of soluble and exchangeable acidity) was determined
by titration of the KCl extract to pH 6.5 (Method Code 23F) (Ahern et al. 2004).
Total carbon (%C) and total nitrogen (%N) were measured on powdered oven-dried samples by combustion
using a LECO-CNS 2000 analyser. The near-total metal(loid) (Ag, Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, U
and Zn) and boron (B) contents were determined using an aqua regia digestion method (USEPA Method
3050) (USEPA,1986), and analysed by inductively coupled plasma-mass spectrometry (ICP-MS; Perkin Elmer
NexION 300D ICP-MS) (APHA 3125 ICP-MS; APHA 2005).
Pore-water Analyses
Filtered (0.45 µm) pore-waters were extracted after centrifuging the soil and sediment samples at 3,000 rpm
for 10 minutes. The parameters measured in the laboratory on the pore-water samples included:
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Alkalinity
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Soluble metal(loid)s
Soluble cations (Ca2+, Mg2+, Na+, K+) and anions (Cl-, Br-)
Soluble sulfur (S), phosphorus (P) and silicon (Si)
Dissolved organic carbon (DOC)
Pore-waters for alkalinity analysis were immediately fixed using Bromophenol blue traps (Sarazin et al. 1999)
Alkalinity was quantified colorimetrically using a Hach DR/2800 spectrophotometer, and alkalinity standards
were determined with 0.01 M HCl using the Gran procedure (Stumm and Morgan 1996).
Samples analysed for soluble metal(loid)s (Ag, Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Se, V and
Zn), cations (Ca2+, Mg2+, K+, Na+), anions (Br-, Cl-) and other elements (S, P, Si) were acidified with 0.2 mL of
concentrated nitric acid (HNO3) and analysed using ICP-MS (APHA 3125 ICP-MS; APHA 2005).
The dissolved organic carbon (DOC) contents were analysed using a Shimadzu TOC-L Analyzer following the
APHA 5310 B high-temperature combustion method (APHA 2005).
References
Ahern C.R., L.A. Sullivan, and A.E. McElnea. 2004. Laboratory methods guidelines 2004 - acid sulfate soils. In:
'Queensland Acid Sulfate Soil Technical Manual'. (Department of Natural Resources, Mines and Energy:
Indooroopilly, Queensland).
APHA. 2005 'Standard methods for the examination of water and wastewater (21st Ed.).' (American Public
Health Association - American Water Works Association: Baltimore, USA).
Burton E.D., R.T. Bush, L.A. Sullivan, and D.R.G. Mitchell. 2007. Reductive transformation of iron and sulfur in
schwertmannite-rich accumulations associated with acidified coastal lowlands. Geochim. Cosmochim.
Acta 71: 4456 - 4473.
Burton E.D., L.A. Sullivan, R.T. Bush, S.G. Johnston and A.F. Keene. 2008. A simple and inexpensive chromiumreducible sulfur method for acid-sulfate soils. Appl. Geochem. 23: 2759-2766.
McGuire M.M. and R.J. Hamers. 2000. Extraction and quantitative analysis of elemental sulfur from sulfide
mineral surfaces by high-performance liquid chromatography. Env. Sci. Tech. 34: 4651-4655.
Sarazin G., G. Michard, and F. Prevot. 1999. A rapid and accurate spectroscopic method for alkalinity
measurements in sea water samples. Water Res. 33: 290-294.
Stumm W. and J.J. Morgan. 1996. Aquatic chemistry. 3rd Ed., John Wiley & Sons, New York.
USEPA. 1986. Acid digestion of sediment, sludge and soils. In: USEPA (Ed.), Test Methods for Evaluating Soil
Waste SW-846. USEPA, Cincinnati, OH, USA.