Standing Committee of Analysts
Hydrocarbons in Soil (and associated materials) working group
Meeting held on 28th October 2014 at EIC offices
Attendees:
Dave Smith
Hazel Davidson
Darrell Hall
Claire Stone
Amy Parekh-Pross
Kate Rawlinson
Sam Ibbott
DS
HD
DH
CS
AP
KR
SI
Apologies:
Kate Wylie
SAL (Chair)
DETS
Chemtest
I2
ESG
Alcontrol
EIC
Jones
No.
1.
DISCUSSION
Introductions were made by all attendees.
2.
Minutes of last meeting
ACTION
This was the first meeting since 2010, and no minutes were available from
prior meetings.
3.
DS had circulated the last draft version to all attendees prior to the meeting,
and agreed to act as Chair
.
General comments and background
DS gave the background of this document, which commenced in about 2004.
The original group was chaired by Dr. David Westwood of the EA, but no
further meetings were held after he retired in 2011.
The document is 107 pages long, and very comprehensive, with fully detailed
methods. It has undergone a number of revisions and now includes several
methods. Some validation data is included, but this was not considered to be
complete.
Some round robin exercises were performed by the group, using soils
supplied by Shell Research, but there was little consistency in the
methods/solvent used, therefore no meaningful evaluation could be
performed.
KR questioned the purpose of the SCA, and HD agreed to provide objectives
and the mission statement
4
Review of method
4.1
The general consensus was that the document did not reflect current practice
and that the inclusion of both DCM extraction and hexane/acetone extraction
would still lead to inconsistencies between laboratories. The inclusion of two
screening methods (C6 - 40 and C8 – 40) was also questioned.
HD
The following changes were agreed:
4.2
In the title, ‘similar matrices’ should be changed to ‘ associated materials’ in
line with other SCA soil documents.
4.3
All dates to be changed to reflect current status of the document.
4.4
Method CB should be deleted, as it does not reflect current practice.
4.5
Method CA either requires validation data, or could be incorporated as a
stage in method AA and therefore deleted.
4.6
The acronyms VPH, EPH, DRO and LORO should be included in the glossary
and the text where appropriate.
4.7
The use of methanol needs including in the introduction, plus when and where
it should be used.
4.8
The references need updating.
4.9
The analysis of aliphatics needs to be incorporated into method AB.
4.10
The para concerning removal of material from samples needs rewriting to
reflect the updated SCA method for the prepation of soils.
4.11
Delete any references to mineral oil or engine oil, as it was agreed these are
confusing.
4.12
There is a chromatogram missing on p.39.
4.13
Xylenes should refer to ortho, meta and para (not the C numbers).
4.14
A paragraph needs adding into method AA stating that GCFID or GCMS can
be used for total volatiles, but not for banding.
HD agreed to edit the method.
5
Agreed Actions
5.1
Each laboratory should provide data on a small trial to compare DCM and
hexane/acetone (1:1) as the preferred solvent:
Use any 10 as received soils containing mid range levels of hydrocarbons
(500 – 3000 mg/kg). Also include a CRM and IRM, if available.
Mix the soils well, and remove 2 subsamples. Perform a moisture content on
a further subsample.
Extract one set in DCM plus anhydrous sodium sulphate and the other set in
hexane/acetone, using whichever is the lab’s standard extraction method, but
it must be the same for both.
After extraction, add 50 - 100 ml of water to the hexane/acetone extract,
allowing the acetone to partition out. The hexane layer is then used for
subsequent analysis.
For all samples, reduce half the extract to dryness and weigh to report ‘total
extractable hydrocarbons’.
Perform ali/aro separation on the second half of the 5 highest samples from
each set, and analyse these by GCFID to report the bands.
HD
All
5.2
Supply all data to DS by 31st December, and include the following
information:
All
Brief description of soil
Any material removed from soil
Any pre-preparative treatments
Weight of soil used for extraction
Moisture content of soil
Solvent used
Volume of solvent
Soil/solvent ratio
Extraction method
Calibration standard for both aliphatic and aromatic fractions
Calibration range for both aliphatic and aromatic fractions
Dilution factors for both aliphatic and aromatic fractions
Known values of CRM and IRM, if used
5.3
DS to circulate the collated data by 19th January 2015.
DS
5.4
DS and APP to review USEPA methods and availability of validation data.
DS. APP
5.5
DS to provide HD with a Word version of the method.
Post meeting note – DS could not source a Word version, but HD obtained a
slightly earlier version from Mark Gale (SCA Secretariat)
DS
7
Date of next meeting
This will be on 28th January 2015 at the EIC offices from 1.00 – 5.00 p.m.