Environmental Forensics

Proceedings of the 2009 INEF Annual Conference

By Robert D. Morrison, Gwen O’Sullivan

The Royal Society of Chemistry

Copyright © 2010 The Royal Society of Chemistry
All rights reserved.
ISBN: 978-1-84755-258-7

Contents

Differentiating Aged Petroleum Hydrocarbons from Modern Phytogenic Hydrocarbons in High Organic Content Soils Using Biomarkers Gwen O’Sullivan, Jay Bilyk, Jevins Waddell, and Court Sandau, 1,
Oil Profiling of a Diesel Spill at Sea: Semi-Volatile Organics and Trace Metals Analysis Sonia Campbell, 12,
Estimating Contaminant Emissions via Wind-Blown Particles Walt Shields and Rengie Chan, 22,
Stable Isotope Diagnostics of Chlorinated Solvents in Contaminated Aquifers Gregory Smith and Yi Wang, 30,
Forensic Application of Environmental Isotopes in Chlorinated Solvent Investigations Yi Wang, Alan Jeffrey and Gregory Smith, 38,
Forensic Visualization of the Transport and Accumulation of Anthracene in Kandelia Caudel (L.) Druce Leaves Ping Wang, Yaxian Zhu and Yong Zhang, 51,
Position Specific Isotope Analysis: the Ultimate Tool in Environmental Forensics? Caroline Gauchotte, Gillian Connal, Gwen O’Sullivan and Robert Kalin, 60,
Application of CDOM Fluorescence to Indicate Physical Dynamics on the Ocean Surface Jian Ning Chen, Fang Wu, Mao-Cai He, Bei-Bei Liu, Yaxian Zhu and Yong Zhang, 71,
Chemical Oxidative Degradation of MTBE in Groundwater by Waste Steel Scrap Jai-Young Lee, So-Young Moon, Sang-!! Choi and Byung-Taek Oh, 83,
Dendroecological Methods for Dating Petroleum Releases to Soil and Groundwater: The Use of Elemental Markers Gil Oudijk and Jean-Christopher Balouet, 91,
Environmental Forensics and Environmental Law in French and European Perspectives: A Two Ways Approach Yvan Razafindratandra, 108,
Scientist as Historian or Historian as Scientist: Developing Useful History for Litigation of Groundwater Contamination by TCE Stanley Feenstra and James Feenstra, 114,
Environmental Forensics: An Evolutionary Perspective Paul Philp, 129,
Gasoline Leakage Forensics using Compound-Specific Hydrogen Isotope Analyses: A Case Study Yi Wang, 153,
Forensic Tracking of Sewage Waste Stephen Mudge and Wolfram Meier-Augenstein, 164,
Sulphur and Boron Isotope Variations to Track Air Pollutant Deposition in the Castle River of Southern Alberta, Canada John Xie, Ann-Lise Norman, Steve Henley and Michael Wieser, 176,
The Use and Misuse of the National Health and Nutrition Examination Survey (Nhanes) Data for Assessing Human Exposure to Environmental Chemicals Donald Patterson, Gwen 0 ‘Sullivan and Court Sandau, 188,
Principle Components Analysis of Environmental Chemical Data: Experience and Application Glenn Johnson, 202,
Forensic Methods for Chlorinated Solvents Brian Murphy, 210,
Use of Statistical Tools to Improve Confidence in Analytical Conclusions Rachel Mohler and Jun Lu, 228,
Molecular Microbial Forensics Raul Cano, 240,
Measurement of Laboratory Uncertainty Chris Swyngedouw and Robert Lessard, 259,
Sampling Strategies in Environmental Criminal Cases Marion Stelling and Anita Biezeman, 275,
Age Dating the Release of PCE, TCE and TCA using Stabilizers and Feedstock Impurities as Indicators Robert Morrison and Justin Hone, 289,
Author Index, 305,
Subject Index, 306,

CHAPTER 1

DIFFERENTIATING AGED PETROLEUM HYDROCARBONS FROM MODERN PHYTOGENIC HYDROCARBONS IN HIGH ORGANIC CONTENT SOILS USING BIOMARKERS

G. O’Sullivan, J. Bilyk, J. Waddell, and C.D. Sandau

TRIUM Inc., 2207, 120–5 Avenue W, Cochrane, AB T4C OA4, Canada

I INTRODUCTION

Canada is rich in petroleum hydrocarbon (PHCs) resources and processes involved in the extraction and transportation of these resources has led to the detection of elevated levels of petrogenic hydrocarbons at a wide variety of sites including well sites and along pipelines. Often, particularly in remote locations, PHCs impacts are not detected until the well head or pipeline is decommissioned and it is at this point that remediation activities occur to achieve site closure as required by environmental regulations.

Current PHC analytical protocols from the Canadian Council of Ministers of the Environment (CCME) categorizes a wide range of PHC compounds into four fractions Fl to F4; F1 composed of carbon number (C) C6 to C10, F2 from C10 to C16, F3 from C16 to C32, and F4 from C32 to C50. The CCME protocols therefore assume that all hydrocarbons detected in the C6 to C50 range originate from petroleum sources. However organically rich soils, such as muskeg or peat, contain naturally occurring phytogenic hydrocarbons, which may be detected within the F3 fraction. Phytogenic material in soils and sediments may be derived from the presence of plant debris and are prevalent in moist, highly vegetated environments where organic material may accumulate (e.g. peat and marshlands). Phytogenic compounds may include tannins, waxes, terpenes, fats, oils, and polar compounds, such as organic acids, alcohols, and phenols.

If additional sample clean-up, prior to analysis, is not performed for soil and sediment samples containing phytogenic materials, the presence of these compounds may inflate the measured concentrations of PHCs in the samples. The presence of phytogenic hydrocarbons may also increase the perceived extent of an impact since natural background hydrocarbons may be identified as PHCs. Remedial action plans require the delineation of impacts, which at sites with organically rich soils is made difficult, using regulatory methods, by the inability to separate naturally occurring phytogenic organic material from petrogenic sources. The use of more advance analytical techniques such as gas chromatogram mass spectrometry (GS-MS) for the analysis of PHC biomarker compounds may be used as a complementary tool to indicate the conclusive presence of PHCs.

2 PETROLUEM BIOMARKERS

Petroleum biomarkers are chemical fossils that can act as unique tracers for petroleum contaminants. They originate from previously living organisms which constitute the organic materials from which PHCs are derived (Figure 1). During PHC formation mechanisms, such as sedimentation and diagenesis (biological, chemical, and physical alteration of organic matter in sediments), the basic structures of biomarkers remain relatively intact and therefore give scientists an indication of the source material (e.g. terrestrial or marine etc.).

During catagenesis (thermal alteration of organic matter in rocks through burial and heating), biomarkers undergo structural changes. The degree of change may be used to infer the age of PHCs. Therefore, biomarkers may provide information pertaining to the nature, source, type, and geological conditions of formation of PHCs. A number of biomarker classes, covering a wide range of boiling points and carbon numbers have been used to differentiate sources of hydrocarbons including n-alkanes, isoprenoids, sesquiterpanes, tri, tetra-, and pentacyclic terpanes etc. In particular n-alkanes may be used to differentiate naturally occurring modem phytogenic sources of hydrocarbons from PHC derived sources. More resistant biomarkers have been used to characterize degraded petroleum hydrocarbons, particularly aged crude oil, where weathering has removed potential indicator compounds such as the n-alkanes, branched alkanes, polycyclic aromatic hydrocarbons and their alkyl homologues. A number of biomarkers are extremely weather resistant and may be present in the environment long after other compounds may be weathered.

Within this paper we will look at the application of conventional PHC analysis in conjunction with biomarker analysis to distinguish between hydrocarbons derived from PHC and those present naturally from phytogenic hydrocarbons.

3 SITE DESCRIPTION

In February 2007, an investigation at a former well-site uncovered PHC impacts at the site. During its operation it was believed to have produced crude oil, natural gas, and formation water. The lease and surrounding area consists of low-lying peat marshland and forest with standing water observed on or near surface (Figure 2). The regional topography is generally flat and the site gradually slopes towards the southwest. It is assumed that local groundwater flow is towards the unnamed tributary located approximately 100 m west of the site. Regional surficial geology in the area is lacustrine and fluvial deposits of glacial till. Regional groundwater flow is towards river which exists approximately 6 km to the west of the site. The Stakeholder requested that impacted materials be excavated and replaced with clean infill material.

The presence of organically rich soil at the site had the potential to interfere with the delineation of PHC impacts. Therefore, a method was required to identify background concentrations of natural hydrocarbons and to delineate the PHC impacts to ensure that in such a sensitive environment only soils impacted as a result of oil and gas exploration and production activities were removed.

4 FIELD AND ANALYTICAL

A number of boreholes and hand auger holes were advanced at the site and locations were selected based on the location of the former well head, possible drilling sump, and areas suspected to represent background conditions (Figure 3). Three hand auger samples were also collected outside the lease area to the north and south to help determine background values. Based on the nature of oil and gas drilling procedures and the reported production information for the on-site well, collected soil samples were analyzed for salinity, metals, and PHC constituents, including benzene, toluene, ethylbenzene, xylenes (BTEX), and PHC fractions F1 to F4. A number of soil samples were also sent for particle size distribution analysis to determine grain size.

For PHC analysis CCME recommend that soils containing partially degraded PHCs under go careful silica gel cleanup and that contaminated and uncontaminated soils be compared. Silica gel clean-up removes any organic, polar compounds eluting with the petroleum fractions. An example of silica gel clean-up may be seen in Figure 4. In the original sample, the baseline increases with time and the chromatogram is very busy, showing large interferences from the numerous compounds in the sample. After silica gel clean-up the difference is very apparent and suggests that the sample contained a number of polar compounds (organic matter) which were removed by the clean-up. Silica gel cleanup reduces the detected concentration in F3 and F4 fraction by as much as 75%. The application of this method is approved by regulators as the treatment only removes the polar compounds to which the PHC guidelines do not apply.

The CCME also advise that in soils with high organic content that GCMS techniques should be applied to confirm PHC impacts or subtract a “blank” comparison soil. Due to the high organic content of the soils on-site, petroleum biomarker analysis was also conducted to identify the source, petrogenic or phytogenic, of detected hydrocarbon concentrations to allow the delineation of well-site related hydrocarbons. Identification of biomarker compounds was completed using GC-MS and the original extract from the PHC analysis. The GC was operated in full scan mode and post run data was ion filtered and library searched for prominent peaks as well as identification of know petroleum biomarkers. The biomarkers targets sought included acyclic isoprenoid compounds, PAH compounds, terpanes, hopanes, and triaromatic steranes.

5 RESULTS

Results of hydrocarbon analyses in soil were interpreted in the context of the Alberta Environment (AENV) Tier 1 Soil and Groundwater Remediation Guidelines (June, 2007). Additionally, results for metals and salinity parameters were referenced to the CCME Canadian Environmental Quality Guidelines (1999) and the AENV Salt Contamination Assessment and Remediation Guidelines (2001). In determining the appropriate remedial guidelines to apply at the site, the grain-size of the soil layer governing groundwater flow was the deciding factor. Based on the presence of peat material within the saturated zone and laboratory grain-size analysis indicating the presence of stratified grain-size, including both fine and coarse grain size, the conservative coarse-grained guidelines were adopted. Concentrations of all salinity and metal parameters in the soil samples satisfied the applicable guidelines. However, concentrations of one or more of the PHC constituents exceeded the applicable guidelines (Table 1).

Figure 5 summarizes the relative percent of the extractable PHC fractions. The majority of PHC exceedences were related to the F3 fraction with concentrations in a number of sample locations exceeding the applicable guideline (300 mg/kg). Delineation of impacts using PHC values would suggest that excavations would be required in large portions of the site extending beyond the northern and southern boundaries. The excavation would also destroy large sections of natural wooded area in the north, west, and southern portions of the site where no evidence of toxicity to plant life was found.

Due to the presence of peat materials and the potential for natural phytogenic material to elevate PHC values samples which exceeded regulatory guidelines for F2 through to F4 were sent for additional biomarker analysis to confirm the presence of petroleum impacts and to determine the concentration range of natural background hydrocarbons.

Chromatograms of samples where biomarkers were present and absent along with an overlay of both an isoprenoid and carbon standard are shown in Figure 6. For additional assurance for biomarker identification, the mass-spectra from suspected biomarker peaks were compared to library spectra (Figure 7) and in all cases, provided a tight match between library spectra and chromatographic spectra. From the chromatograms it was obvious that the samples were severely weathered, as the n-paraffins have disappeared and biomarkers have become the predominant peaks. Table 2 summarises the results from the biomarker analysis, five samples were found to have biomarkers present. The five impacted samples were all located in close proximity to the former well head and had concentrations of F3 in the range of 1350 to 9720 mg/kg. The remaining samples (where biomarkers were absent) had F3 concentrations in the range of 292 to 1380 mg/kg. Since these samples had no indicators of petrogenic sources of biomarkers, these samples are thought to represent natural background values even though they exceeded applicable guidelines for the region.

With this data, statistically determined site-specific background levels of hydrocarbons could be calculated and used for potential relaxation of guidelines. For this case study, the biomarker data was used to delineate the petroleum impacts and to determine the area requiring excavation (Figure 3). Approximately 2,800 tonnes (1,800 m3) of impacted soil was excavated from the site and transported to a licensed landfill, with the equivalent importation of peat/organic backfill. Natural vegetation has begun to return to the excavated area.

6 CONCLUSIONS

This study should resonate with landowners and regulators whom are involved in the reclamation of well-sites impacted with PHCs in areas with background phytogenic organic materials. The study highlighted the benefit of applying petroleum biomarkers to positively identify and confirm the presence of petroleum products in areas with significant background levels of phytogenic (naturally occurring) organic material to reduce the extent of the remedial excavation. The study also indicated that naturally occurring hydrocarbons have the potential to be present at concentrations above guidelines and that site-specific conditions should be taken into consideration when evaluating remediation targets.

CHAPTER 2

OIL PROFILING OF A DIESEL SPILL AT SEA: SEMI-VOLATILE ORGANICS AND TRACE METALS ANALYSIS

Sonia Campbell

Agricultural Diagnostic Service Center, University of Hawaii, Honolulu HI 96822, USA

1 INTRODUCTION

Oil spills at sea can have damaging and lingering effects on the environment, as demonstrated by the 20 year old incident involving the Exxon Valdez tanker in the Prince Williams Sound in Alaska, or the more recent Erika oil spill in 1999 on the Atlantic coast of France. Both incidents involved the release of heavy fuel oil product, and the environmental and economical impact of both are undeniable and still felt in the impacted regions. In both cases, the spill source was known. When this is the case, control measures such as oil skimmers, pumps, booms, or dispersant spray systems can be deployed as soon as an incident is detected to reduce the spread of the released product. Often, however, a spill source is unknown and a release can go on for days or weeks, until the source is finally located, as in the 2001-2002 case of the 1953 sunken vessel SS Jacob Luckenbach releasing tar balls off the coast of San Mateo, Califomia.

Fast and accurate source identification is always one of the goals during an emergency event response, to minimize spreading and eventually stop the release of contaminants to the environment. Here we describe the work performed in the first few hours and days after the running aground of a naval vessel outside a reef fronting the Honolulu International Airport runway, a few miles away from Waikiki beach. The coastal waters of Hawaii being home to a number of endangered species of marine wildlife, as well as a high profile tourist destination, the consequences of an oil spill in the area, such as potential environmental and economical impact, would be severe.

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