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Total Recoverable Hydrocarbons: NEPM Reporting

The National Environmental Protection (Assessment of Site Contamination) Amendment Measure 2013 (No 1) (NEPM) clarifies definitions, extraction methods and reporting fractions for hydrocarbon analyses of samples from contaminated sites. It states that total recoverable hydrocarbons (TRH):

… is equivalent to the previously used total petroleum hydrocarbons (TPH) and represents extracted biogenic (biological) and petrogenic (petroleum) hydrocarbons by selected solvents.

NEPM requires modification of the TRH carbon chain fractions being reported to allow correlation with health screening levels for various fuel types. NEPM also defines how the concentration of each fraction is determined, for example:

  • fraction 1 (F1) includes all the hydrocarbons eluting (elution is closely correlated to boiling point) between n-hexane (C6) and n-decane (C10) with the sum of BTEX compounds subtracted
  • fraction 2 (F2) is calculated as the difference between the >C10–C16 fraction and naphthalene; the concentration of naphthalene is derived from the volatile TRH analysis (purge and trap GC-MS)

NMI’s Capabilities

To assist with the transition to NEPM reporting:

Clients requesting TPH or TRH tests will receive all the hydrocarbon fractions in the table below.

NEPM Total Recoverable Hydrocarbons – Silica (TRH–silica)

This test can be requested when samples are suspected of containing significant levels of non-petroleum based interferences (ie trade waste, soils with high organic content). The test will have the title NEPM Total Recoverable Hydrocarbons – Silica where the semi-volatile fractions from >C10–C40 are reported.

For further information please contact customerservice@measurement.gov.au, 1300 722 845 or use our on-line form.

 
NMI method
Limit of reporting for soil (mg/kg) Limit of reporting for water (µg/L)
Total Recoverable Hydrocarbons (formerly TPH)
TRH C6–C9
NGCMS_1121
<25
<25
TRH C10–C14
NGCMS_1112
<50
<25
TRH C15–C28
NGCMS_1112
<100
<100
TRH C29–C36
NGCMS_1112
<100
<100
NEPM Total Recoverable Hydrocarbons
TRH C6–C10
NGCMS_1121
<25
<25
TRH C6–C10 less BTEX (F1)
NGCMS_1121
<25
<25
TRH >C10–C16
NGCMS_1112
<50
<25
TRH >C10–C16 less Naph (F2)
NGCMS_1112
<50
<25
TRH >C16–C34 (F3)
NGCMS_1112
<100
<100
TRH >C34–C40 (F4)
NGCMS_1112
<100
<100