Lorenzi, Damien (2011) A Comparison of Polycyclic Aromatic Hydrocarbon Mobilization from ...

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by  Ellen Cole

Citation: Lorenzi, Damien (2011) A Comparison of Polycyclic Aromatic Hydrocarbon
Mobilization from Environmental Matrices. Doctoral thesis, Northumbria University.
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A COMPARISON OF POLYCYCLIC AROMATIC
HYDROCARBON MOBILIZATION FROM
ENVIRONMENTAL MATRICES

DAMIEN CEDRIC LORENZI

PhD

2011
A COMPARISON OF POLYCYCLIC AROMATIC
HYDROCARBON MOBILIZATION FROM
ENVIRONMENTAL MATRICES

DAMIEN CEDRIC LORENZI

A thesis submitted in partial fulfilment of the
requirements of Northumbria University at
Newcastle-upon-Tyne for the degree of Doctor of
Philosophy

Research undertaken in the School of Life
Sciences and in collaboration with the British
Geological Survey, Keyworth

April 2011
Abstract

A method has been developed to analyse PAHs in solid environmental matrices using
an in-situ PFE-GC-MS method. The method involves the use of 2 g of alumina as the
in-situ clean-up sorbent, in order to remove interferences and impurities in the soils
that could contaminate the instrument. By using this method, samples from two sites
have been analysed for PAHs content, specifically (i) soils from a contaminated
former Tar Works site, and (ii) urban road dust from Newcastle upon Tyne, UK. It was
found that particle size was a significant parameter in both cases, showing a higher
concentration (from 9 to 1404 mg/kg in the Tar Works, and 0.5 to 95 mg/kg in the road
dust site) in the smaller grain size (< 250 µm); this is important when considering the
ingestion exposure pathway as smaller particles are more likely to be ingested by
children via hand-to-mouth behaviour. In addition, the source of the PAHs was
investigated in the anthropogenically contaminated areas; it was found that pyrogenic
sources (higher molecular weight PAHs, 4-5-6 rings) of PAHs were significantly more
abundant compared to petrogenic sources (lower molecular weight PAHs: 2-3 rings).
Generally the lower molecular weight such as naphthalene, acenaphthene,
acenaphthylene and fluorene were found in lower concentration than fluoranthene,
pyrene and other higher molecular weight PAH. In the case of the Tar Works lower
molecular weights PAH were showing individual PAH concentration below 50 mg/kg
whereas higher molecular weights were showing individual concentrations up to 270
mg/kg. The same trend was observed in the road dust samples, and was clearly
identified by using ratios of PAH concentration to demonstrate dominance of
pyrogenic sources. In this latter case, the pyrogenic sources were clearly identified as
vehicle exhaust. However, other sources were identified such as the road pavement
and the tire debris as potential sources of PAHs in urban areas. In the former case the
PAH distribution was attributed to the locations of the chemicals productions areas in
the former industrial site. The mean daily oral intake was used as an estimate of the
environmental health risk from the sites; values of PAH intake were determined based
on the PAH individual concentration and compared against known values. Risk was
often present for pyrogenic PAHs in road dust and soil samples. Further investigation
of the environmental health risk was realized using a physiologically-based extraction
test on soil samples from the former Tar works; the results, using a fed-version of the
test, showed elevated bioaccessibilities of PAHs, mainly due to the presence of food
and the lipophilicity of PAHs, however other PAH properties could influence their
individual mobilizations such as the molecular weight, the ring number and the liquid-
to-soil ratio.
It was noticed that the risk can be evaluated differently and can show different
conclusions depending on the risk assessment chosen. Overall, the determination of
PAHs in environmental soil and urban dust samples has highlighted the necessity to
assess the potential impact on human health of their presence. The use of the fed-
version of the physiologically-based extraction test is one tool that could be used to
assess the environmental health risk to humans. This tool was shown to be robust
using an inter-laboratory study, as values for total PAH content and bioaccessible
fractions were within the same acceptable range.

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List of contents

List of contents ............................................................................................................. i
List of Figures ............................................................................................................ vi
List of Tables ............................................................................................................. ix
Acknowledgements .................................................................................................... xi
Declaration................................................................................................................ xii
Chapter 1: PAH exposure in environmental matrices
1.1 Introduction........................................................................................................ 1
1.2 Exposure pathways to pollutants and environmental matrices ........................... 2
1.3 Importance of particle size ................................................................................. 4
1.4 The Contaminated Land Exposure Assessment (CLEA) model ......................... 4
1.5 Soil guideline values and PAHs ......................................................................... 8
1.6 Occurrence of PAHs in environmental matrices ................................................. 8
1.7 PAHs properties .............................................................................................. 12
1.8 Conclusion....................................................................................................... 13
References ............................................................................................................ 14
Chapter 2: PAH mobilization in the human gastrointestinal tract
2.1 Introduction...................................................................................................... 20
2.2 Physiology of the gastrointestinal tract ............................................................. 23
2.3 Development and design of an in vitro gastrointestinal test ............................. 25
2.4 Parameters influencing mobilization inside the gut .......................................... 27
2.4.1 Bile salts ................................................................................................... 27
2.4.2 Organic matter .......................................................................................... 30
2.4.3 Food ......................................................................................................... 31
2.4.4 Other parameters ...................................................................................... 31
2.4.5 pH and residence time .............................................................................. 32
2.5 Development of a fed version of the in vitro gastrointestinal test ...................... 33
2.6 Validation of the method: quality and reproducibility ........................................ 36
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2.7 Consideration in risk assessment .................................................................... 37
2.8 Extractions methods and analysis following PBETs ......................................... 37
2.9 Conclusion....................................................................................................... 42
References ............................................................................................................ 43
Chapter 3: Sampling, preparation and analysis of contaminated urban soils
3.1 Introduction...................................................................................................... 50
3.2 Sampling strategies ......................................................................................... 52
3.3 Pre-treatment and storage of samples ............................................................. 54
3.4 Extraction and purification procedures ............................................................. 56
3.4.1 Extraction of PAHs from solid environmental matrices .............................. 56
3.4.2 Pressurized fluid extraction ....................................................................... 57
3.4.3 Clean-up methods ..................................................................................... 58
3.4.4 Clean-up using copper powder ................................................................. 59
3.4.5 Pre-concentration step .............................................................................. 59
3.5 Analysis ........................................................................................................... 59
3.5.1 Description of gas chromatography-mass spectrometry principle .............. 59
3.5.2 Analysis of PAHs using chromatography and mass spectrometry ............. 61
3.6 Quality assurance and quality control .............................................................. 61
3.7 Conclusions and aims of the project ................................................................ 62
References ............................................................................................................ 63
Chapter 4: Development of a method to establish total PAH content in soils
4.1 Introduction...................................................................................................... 68
4.2 Experiment ...................................................................................................... 69
4.2.1 Chemicals ................................................................................................. 69
4.2.2 Instrumentation and laboratory equipment ................................................ 70
4.2.3 Soil preparation ......................................................................................... 71
4.2.4 PFE procedure .......................................................................................... 71
4.2.4.1 Conventional approach ....................................................................... 71
4.2.4.2 In-situ approach .................................................................................. 72
4.2.4.3. Copper clean-up ................................................................................ 73
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4.2.4.4 Certified Reference Material analysis ................................................. 73
4.2.4.5 Preliminary information on method development and validation ......... 73
4.3 Results and Discussion ................................................................................... 74
4.3.1 Example of chromatogram with 16 PAHs .................................................. 74
4.3.2 Analytical figures of merit .......................................................................... 75
4.3.3 PFE procedure .......................................................................................... 75
4.3.3.1 Conventional approach ....................................................................... 75
4.3.3.2. Adsorbent amount influence .............................................................. 77
4.3.3.3. Spiking procedure of the in-situ approach .......................................... 78
4.3.3.4. Comparison of conventional and in-situ approach ............................. 80
4.3.4. Copper influence ...................................................................................... 81
4.3.5 Analysis of a Certified Reference Material ................................................. 82
4.4 Conclusion....................................................................................................... 82
References ............................................................................................................ 83
Chapter 5: An investigation into the occurrence and distribution of PAH, in two
soil size fractions, on a former industrial site, NE England, UK using in-situ
PFE-GC-MS
5.1 Introduction...................................................................................................... 85
5.2 Experimental ................................................................................................... 87
5.2.1 Sampling procedure .................................................................................. 87
5.2.2 Analysis .................................................................................................... 88
5.2.3 In-situ PFE protocol ................................................................................... 88
5.2.4 Determination of soil pH ............................................................................ 89
5.2.5 Determination of soil organic matter content ............................................. 89
5.3 Results and discussion .................................................................................... 89
5.3.1 Preliminary information ............................................................................. 89
5.3.2 Soil total PAH concentrations .................................................................... 90
5.3.3 Soil individual PAH concentrations ............................................................ 93
5.3.4 Distribution and sources of PAHs across the St Anthony‘s Tar Works study
area ................................................................................................................... 96
5.3.5 Influence of organic matter and pH ........................................................... 98
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5.4 Conclusion..................................................................................................... 100
References .......................................................................................................... 101
CHAPTER 6: Application of two versions of an in vitro gastrointestinal
extraction to evaluate oral bioaccessibility of PAH in industrially contaminated
soils
6.1 Introduction.................................................................................................... 106
6.2 Experiment .................................................................................................... 111
6.2.1 The study site .......................................................................................... 111
6.2.2 Apparatus for analysis of total PAHs content........................................... 111
6.2.3 Unified BARGE Method: Chemicals and laboratory equipment ............... 112
6.2.4 Unified BARGE Method: Preparation of the gastrointestinal fluids ........... 113
6.2.5 Unified BARGE Method: Extraction of samples ....................................... 115
6.2.6 Unified BARGE Method: Spiking procedures .......................................... 116
6.2.6.1 Liquid-liquid extraction ...................................................................... 116
6.2.6.2 Solid Phase Extraction...................................................................... 117
6.2.6.3 Solid Phase Micro-Extraction ............................................................ 118
6.2.6.4 Stir-Bar Sorptive Extraction .............................................................. 119
6.2.6.5 Micro Extraction by Packed Sorbent ................................................. 119
6.2.7 FORES(h)t method ................................................................................. 120
6.2.7.1 FORES(h)t method spiking procedure .............................................. 122
6.3 Results and Discussion ................................................................................. 122
6.3.1 Quality control ......................................................................................... 122
6.3.2 Performance of analytical method following UBM ................................... 127
6.3.2.1 Liquid-liquid extraction ...................................................................... 127
6.3.2.2 Solid Phase Extraction...................................................................... 128
6.3.2.3 Stir-Bar Sorptive Extraction .............................................................. 129
6.3.2.4 Solid Phase Micro-Extraction ............................................................ 130
6.3.2.5 Micro-extraction by Packed Sorbent ................................................. 130
6.3.2.6 Conclusion ........................................................................................ 131
6.3.3 Evaluation of bioaccessibilities using the UBM ........................................ 131
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6.3.4 Performance of the analytical method following FORES(h)t .................... 133
6.3.5 Evaluation of PAHs bioaccessible fractions using FORES(h)t ................. 134
6.3.5.1 Comparion of bioaccessible fractions with residual digests and total
content ......................................................................................................... 134
6.3.5.2 Boxplot and PCA interpretation ......................................................... 140
6.3.5.3 Interlaboratory comparison ............................................................... 147
6.3.5.4 Human health risk assessment ......................................................... 150
6.4 Conclusion..................................................................................................... 154
References .......................................................................................................... 156
Chapter 7: Determination of PAH in urban street dust: implications for human
health
7.1 Introduction.................................................................................................... 162
7.2 Experimental ................................................................................................. 165
7.2.1 Collection and preparation of dust samples ............................................. 165
7.2.2 Chemicals ............................................................................................... 165
7.2.3 Procedure ............................................................................................... 165
7.2.4 Organic matter content ............................................................................ 169
7.3 Results and Discussion ................................................................................. 169
7.3.1 PAH content in dust samples .................................................................. 172
7.3.2 Identification of PAH sources (pyrogenic / petrogenic) in road dust ......... 175
7.3.3 Organic matter influence ......................................................................... 177
7.3.4 PAH distribution with respect to particle size ........................................... 178
7.3.5 Mean daily intake estimate of PAHs from urban dust and associated human
health risk ........................................................................................................ 181
7.4 Conclusion..................................................................................................... 183
References .......................................................................................................... 184
Chapter 8: Conclusion and future work
8.1 Conclusion..................................................................................................... 189
8.2 Future prospects ........................................................................................... 191
GLOSSARY ........................................................................................................ 193
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