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Making environmental data meaningful

Where does toluene come from? Petrogenic families and biogenic loners

Watertech 2017

April 3-5, 2017

Where does toluene come from? Petrogenic families and biogenic loners

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Biogenic Toluene? Are you sure?

2Where does toluene come from? Petrogenic families and biogenic loners

Sample B T E X F1 F2 F3 F4

1 ND 0.297 ND ND ND ND 1300 ND

2 ND 0.116 ND ND ND ND 780 ND

3 ND 0.439 ND ND ND 81 870 ND

4 ND 0.090 ND ND ND 290 2300 800

5 ND 0.182 ND ND ND ND 1400 ND

6 ND 0.262 ND ND ND ND 1300 ND

7 ND 0.015 ND ND ND ND 1000 ND

0.078 0.120 0.210 28 210 150 300 2800AB T1 – Coarse, Surface, Natural Areas

Example from poor bog (i1)

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Biogenic Toluene? Are you sure?

3

• Not discussed in peer-reviewed literature

• Formation mechanism not understood

• Observed by standard analytical methods• But no legally-defensible method for

demonstration of origin

Where does toluene come from? Petrogenic families and biogenic loners

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Biogenic Toluene? Are you sure?

4

Regulatory understanding…•Constituent of petroleum and products•Highly mobile chemical•Health-based guidelines

Where does toluene come from? Petrogenic families and biogenic loners

How does a regulator acknowledge biogenic toluene at an investigation on that basis?

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Biogenic Toluene? Are you sure?

5

Method already well described.• Arson investigation for ‘ignitable liquids’• ASTM method• AGAT is the forensic laboratory for arson analysis

for Govt of AB, and AB Forestry.

Where does toluene come from? Petrogenic families and biogenic loners

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Gasoline

6Where does toluene come from? Petrogenic families and biogenic loners

Toluene

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Gasoline

7Where does toluene come from? Petrogenic families and biogenic loners

Toluene

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Weathered gasoline in soil

8Where does toluene come from? Petrogenic families and biogenic loners

Toluene

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Weathered gasoline in soil

9Where does toluene come from? Petrogenic families and biogenic loners

Toluene

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Peat from treed poor bog (i1)

10Where does toluene come from? Petrogenic families and biogenic loners

Toluene p-cymene

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Gasoline

11Where does toluene come from? Petrogenic families and biogenic loners

Toluene

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Peat from treed poor bog (i1)

12Where does toluene come from? Petrogenic families and biogenic loners

Toluene p-cymene

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Decomposition Pathways

13Where does toluene come from? Petrogenic families and biogenic loners

pinene p-cymene toluene

phenylalanine phenylacetate toluene

An amino acid

A terpene

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Peat from treed poor bog (i1) & poor fen (j1)

14Where does toluene come from? Petrogenic families and biogenic loners

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Diagnostic Groups

Focus on 2 key groups.

• BTEX

• Cymenes

15Where does toluene come from? Petrogenic families and biogenic loners

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Diagnostic Groups - BTEX

16

A standard forensic method for analysis of VOCs is the ratio

of BTEX.

Six closely related chemicals.

In petroleum all 6 may be present.

In natural wetlands only 1 is present.

benzene ethylbenzene xylenes (3)

Where does toluene come from? Petrogenic families and biogenic loners

toluene

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The BTEX

17

Natural Petroleum

Where does toluene come from? Petrogenic families and biogenic loners

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Diagnostic Groups – The Cymenes

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p-cymeneo-cymene m-cymene

Three closely related chemicals.

In petroleum all 3 are present.

In natural wetlands only 1 is present.

Where does toluene come from? Petrogenic families and biogenic loners

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The Cymenes

19

Natural Petroleum

Where does toluene come from? Petrogenic families and biogenic loners

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Diagnostic Chemical Ratios

20Where does toluene come from? Petrogenic families and biogenic loners

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Diagnostic Chemical Ratios

21Where does toluene come from? Petrogenic families and biogenic loners

Peat

SAGD

Light RefinedOils &

Heavy Refined

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Diagnostic Chemical Ratios

22

Biogenic Toluene

Petrogenic Toluene

Where does toluene come from? Petrogenic families and biogenic loners

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Where does biogenic toluene come from?

Where does toluene come from? Petrogenic families and biogenic loners

© 2017 Chemistry Matters Inc. 24Where does toluene come from? Petrogenic families and biogenic loners

Very rich organic environment

Limited nutrients and oxygen

Anaerobic water

Limited ‘decomposition’ pathways

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Source: geogratis.gc.ca

Wetlands

Fort McMurray

Edmonton

Peace RiverCold Lake

High Level

Where does toluene come from? Petrogenic families and biogenic loners

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Ecosite type?

26Where does toluene come from? Petrogenic families and biogenic loners

Site 1poor bog i1 – pH 3.6 to 5.6, low TDS, low EC

Site 2poor fen j1 – pH 7.6 to 8.2, high TDS, high EC (adjacent poor bog)

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Ecosite type?

27Where does toluene come from? Petrogenic families and biogenic loners

poor bog i1 poor fen j1

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Peat from treed poor bog (i1) & poor fen (j1)

28Where does toluene come from? Petrogenic families and biogenic loners

Toluene p-cymene

poor bog i1 poor fen j1

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Seasonality?

29Where does toluene come from? Petrogenic families and biogenic loners

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

May July August September October

TolueneConcentra

on(mg/L)

Site 2 – a poor fen (j1). Strong seasonality in water samples.

•Production or movement?

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Toluene in snowpack

30Where does toluene come from? Petrogenic families and biogenic loners

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Conclusions

Natural toluene concentrations are present in peat samples.• Highly specific pattern of chemicals.• Clear diagnostic ratios.

Wetland environment correlates with likely formation mechanisms.

Likely seasonality effects as well as ecosite type.

Where does toluene come from? Petrogenic families and biogenic loners

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Thank You

Where does toluene come from? Petrogenic families and biogenic loners

Where does toluene come from? Petrogenic families and biogenic loners

Look out for the paper soon…

Forensic source attribution for toluene in environmental samples