title: Categorisation and Discrimination of Automotive Glass Fragments by Laser Ablation Inductively Coupled Plasma Mass-Spectrometry (LA-ICP-MS) for Forensic Purposes

authors: Grainger, Megan N.C.

subjects: LA-ICP-MS

abstract: Glass is one of the most common types of trace evidence found at crime scenes and on suspects. Refractive index is presently used for matching recovered and control samples of glass. However, increased quality control in manufacture has substantially reduced the spread of RI values and many samples can no longer be distinguished. Therefore analysis of glass by elemental techniques is required if samples are to be distinguished. This research project was carried out on behalf of the Institute of Environmental Science and Research (ESR), Auckland. The aim was to develop a method to analyse automotive glass fragments by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and create a database which can be used to categorise samples into country of origin and to distinguish samples. 244 glass samples were obtained from ESR which contained 162 laminated and 82 toughened samples from a range of vehicle makes and models manufactured between 2002 and 2006. Two calibration standards (NIST 612 and FGS 2) were compared for their ability to calibrate float glass. FGS 2 is a better standard due to its closer composition to float glass and was used for this research. 23 elements were initially analysed and assessed for accuracy, precision and long term stability. This was cut down to 15 elements for the final method. The relative accuracy and precision of these elements was less than 5 % when compared to the literature values. An inter-laboratory comparison study showed most elements had less than 10 % bias between laboratories when analysing float glass. However, Sn had over 25 % bias between the two laboratories. A homogeneity study of three panes showed no spatial variation for most elements. However, the three Pb isotopes showed spatial variation in the windscreen. In addition, outliers were found for replicates of some database samples and the pooled standard deviation for the database was very large, indicating Pb is not homogeneous in glass. Multivariate analysis was used to investigate the natural splitting of the data. The splitting was influenced by the country of origin from which the raw materials were sourced from for glass manufacture. Australian samples had a clear separation from all samples originating from the Northern Hemisphere. A multiclass classifier correctly categorised 86.87 % of samples into the vehicles‟ country of origin. Correct classification was not higher due to importation of some glass. For example, Australia imports glass from Thailand for the Falcon and Commodore ranges. Statistical methods were compared in their ability to discriminate fragments. The elemental composition range overlap method allowed 80.39 % (164/204) discrimination between samples. Only small elemental variation between Australian samples was observed. With Australian data removed, 93.59 % (146/156) of samples could be distinguished. A three-step method was created to increase the distinguishing power; this used a combination of elemental composition and RI. This procedure was able to distinguish 84.31 % (172/204) samples from the entire database and 94.87 % (148/156) samples with Australian data removed. This method decreased the occurrence of type II errors.

text: Categorisation and Discrimination of Automotive Glass Fragments by Laser Ablation Inductively Coupled Plasma Mass-Spectrometry (LA-ICP-MS) for Forensic Purposes Glass is one of the most common types of trace evidence found at crime scenes and on suspects. Refractive index is presently used for matching recovered and control samples of glass. However, increased quality control in manufacture has substantially reduced the spread of RI values and many samples can no longer be distinguished. Therefore analysis of glass by elemental techniques is required if samples are to be distinguished. This research project was carried out on behalf of the Institute of Environmental Science and Research (ESR), Auckland. The aim was to develop a method to analyse automotive glass fragments by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and create a database which can be used to categorise samples into country of origin and to distinguish samples. 244 glass samples were obtained from ESR which contained 162 laminated and 82 toughened samples from a range of vehicle makes and models manufactured between 2002 and 2006. Two calibration standards (NIST 612 and FGS 2) were compared for their ability to calibrate float glass. FGS 2 is a better standard due to its closer composition to float glass and was used for this research. 23 elements were initially analysed and assessed for accuracy, precision and long term stability. This was cut down to 15 elements for the final method. The relative accuracy and precision of these elements was less than 5 % when compared to the literature values. An inter-laboratory comparison study showed most elements had less than 10 % bias between laboratories when analysing float glass. However, Sn had over 25 % bias between the two laboratories. A homogeneity study of three panes showed no spatial variation for most elements. However, the three Pb isotopes showed spatial variation in the windscreen. In addition, outliers were found for replicates of some database samples and the pooled standard deviation for the database was very large, indicating Pb is not homogeneous in glass. Multivariate analysis was used to investigate the natural splitting of the data. The splitting was influenced by the country of origin from which the raw materials were sourced from for glass manufacture. Australian samples had a clear separation from all samples originating from the Northern Hemisphere. A multiclass classifier correctly categorised 86.87 % of samples into the vehicles‟ country of origin. Correct classification was not higher due to importation of some glass. For example, Australia imports glass from Thailand for the Falcon and Commodore ranges. Statistical methods were compared in their ability to discriminate fragments. The elemental composition range overlap method allowed 80.39 % (164/204) discrimination between samples. Only small elemental variation between Australian samples was observed. With Australian data removed, 93.59 % (146/156) of samples could be distinguished. A three-step method was created to increase the distinguishing power; this used a combination of elemental composition and RI. This procedure was able to distinguish 84.31 % (172/204) samples from the entire database and 94.87 % (148/156) samples with Australian data removed. This method decreased the occurrence of type II errors.

year: 2010

title: Multi-system geochronological and isotopic constraints on age and evolution of the Gaoligongshan metamorphic belt and shear zone system in western Yunnan, China

authors: Eroğlu, Sümeyya

subjects: Gaoligongshan

abstract: The Gaoligongshan metamorphic belt, located east of the Eastern Himalayan Syntaxis (EHS) in the Yunnan province, southwestern China, is a compelling region in which to determine temporal constrains on crustal dynamic processes related to the Himalayan orogeny. We applied multi-system geo- and thermochronology (900 °C to <50 °C) to orthogneiss and mylonites from a major shear zone in the southern Gaoligongshan in order to elucidate the magmatic, cooling and exhumation history of this belt.
Zircon U/Pb data reveal three magmatic events at ∼486 Ma, ∼136 Ma and ∼76 Ma. Similar ages are found in orthoderivative rocks of the neighboring Tengchong and Baoshan blocks, and the Gangdese batholith, suggesting that the southern Gaoligongshan is composed of an assemblage of Lhasa and Qiangtang terrane derived rocks. Muscovite Rb/Sr ages of 35–21 Ma are coeval with the onset of lateral crustal displacement along major shear zones in Eastern Tibet and Indochina, and with the post-collision volcanic activity in western Yunnan. Biotite Rb/Sr and mica 40Ar/39Ar ages provide evidence that mylonitization along the Gaoligongshan shear zone and crustal rotation of the Tengchong and Baoshan blocks proceeded during the Miocene, between 19 and 12 Ma, when the rocks rapidly cooled through the 350–280 °C temperature range. Almost identical 40Ar/39Ar ages reported for the Karakorum–Jiali–Parlung Fault system in Western Tibet suggest that the Gaoligongshan shear zone is the southeastern continuation of this fault, recording the eastward extrusion of Tibet and crustal movement around the EHS. The final stage of exhumation of the Gaoligongshan occurred between 8 and 5 Ma at an average exhumation rate of ∼3 km/Ma as documented by apatite fission-track and apatite (U–Th–Sm)/He data. This rapid exhumation was triggered by crustal root delamination and opening of the Andaman sea.
Our results clearly show that the complex tectonothermal evolution of the Gaoligongshan was influenced by Tibetan extrusion and escape tectonics associated with lower crustal flow around the EHS and the southeastward movement of Indochina and back-arc extension in response to Andaman seafloor spreading.

text: Multi-system geochronological and isotopic constraints on age and evolution of the Gaoligongshan metamorphic belt and shear zone system in western Yunnan, China The Gaoligongshan metamorphic belt, located east of the Eastern Himalayan Syntaxis (EHS) in the Yunnan province, southwestern China, is a compelling region in which to determine temporal constrains on crustal dynamic processes related to the Himalayan orogeny. We applied multi-system geo- and thermochronology (900 °C to <50 °C) to orthogneiss and mylonites from a major shear zone in the southern Gaoligongshan in order to elucidate the magmatic, cooling and exhumation history of this belt.
Zircon U/Pb data reveal three magmatic events at ∼486 Ma, ∼136 Ma and ∼76 Ma. Similar ages are found in orthoderivative rocks of the neighboring Tengchong and Baoshan blocks, and the Gangdese batholith, suggesting that the southern Gaoligongshan is composed of an assemblage of Lhasa and Qiangtang terrane derived rocks. Muscovite Rb/Sr ages of 35–21 Ma are coeval with the onset of lateral crustal displacement along major shear zones in Eastern Tibet and Indochina, and with the post-collision volcanic activity in western Yunnan. Biotite Rb/Sr and mica 40Ar/39Ar ages provide evidence that mylonitization along the Gaoligongshan shear zone and crustal rotation of the Tengchong and Baoshan blocks proceeded during the Miocene, between 19 and 12 Ma, when the rocks rapidly cooled through the 350–280 °C temperature range. Almost identical 40Ar/39Ar ages reported for the Karakorum–Jiali–Parlung Fault system in Western Tibet suggest that the Gaoligongshan shear zone is the southeastern continuation of this fault, recording the eastward extrusion of Tibet and crustal movement around the EHS. The final stage of exhumation of the Gaoligongshan occurred between 8 and 5 Ma at an average exhumation rate of ∼3 km/Ma as documented by apatite fission-track and apatite (U–Th–Sm)/He data. This rapid exhumation was triggered by crustal root delamination and opening of the Andaman sea.
Our results clearly show that the complex tectonothermal evolution of the Gaoligongshan was influenced by Tibetan extrusion and escape tectonics associated with lower crustal flow around the EHS and the southeastward movement of Indochina and back-arc extension in response to Andaman seafloor spreading.

year: 2013

title: Studies on Paphies australis (Mesodesmatidae) in Whangārei, Aotearoa New Zealand: an investigation into their declining health.

authors: Howells, Joanne Elizabeth

abstract: Disease outbreaks in marine species can have devastating consequences, including increasing host mortality, destabilising commercial production, altering ecosystem functioning, and jeopardising human health. A changing ocean climate is expected to increase host stress and the risk of disease outbreaks. Particularly through new and emerging diseases and opportunistic infections.
Wild bivalve molluscs provide economic, ecological, and socio-cultural benefits. Healthy and sustainable kaimoana (shellfish/bivalves, seafood) are intrinsically linked to the wellbeing of many communities in New Zealand. Over the past decade there has been a noticeable decline in the general health of native marine bivalves, characterised by an increase in observation of mass die-offs. Reasons for this are not clear and could be due to a number of factors, such as sedimentation, harvesting pressures, or disease. Baseline health data on wild bivalve populations are very rare and therefore it is very difficult to identify the causation of ill health. There is a need to establish health baselines to help benchmark changes in infection prevalence and intensity and identify drivers of bivalve mortality events.
Wild bivalve populations are often located in remote and isolated parts of New Zealand. When a mortality event occurs, the logistics of obtaining quality samples for accurate diagnosis can be hindered due to time delays and sample degradation. To gain a better understanding of these limitations for diagnostics using bacteriology, in Chapter 2 I investigate typical sample collection methods (i.e., samples collected and sent to a testing laboratory) and sample collections immediately in the field to understand what effect different sample methods have on number and types of bacteria isolated. Although the results of Chapter 2 found there were limitations to both sampling methods, it did identify that typical sampling techniques were not wholly optimal, and the information gained by sampling immediately in the field retained additional information that could be essential for disease diagnostics. Field sampling for bacteriology was applied throughout this thesis research.
Pipi (Paphies australis) are native bivalves to New Zealand, inhabiting the shallow subtidal of estuaries and bays. Pipi have suffered serious population declines in an area of northern New Zealand (Whangārei) since 2009. I investigate possible drivers of the poor health of pipi in Whangārei, with the objective of identifying the mechanisms that have contributed to the decline, and prevention of the recovery of pipi in Whangārei, with a primary focus of disease as a causative agent. I establish a health baseline of pipi from Whangārei using histopathology, bacteriology, and qPCR of Endozoicomonas spp., a bacteria previously identified in mortality bivalves (Chapter 3). The health baseline was compared against samples collected during three mass mortality events to help identify drivers of mass mortality events (Chapter 4). Through laboratory experimentation, I test whether pipi exposed to stressors had higher infection intensity and prevalence of Endozoicomonas spp. (Chapter 5). Finally, using archived samples, I test whether the baseline data established was consistent through time and help to provide insights into considerations when analysing bivalve mass mortality events (Chapter 6).
I found that Endozoicomonas spp. make an important part of pipi host microbiome. Although Endozoicomonas spp. are highly prevalent in pipi collected during a mass mortality event, their infection intensity was significantly lower in moribund pipi than healthy pipi. The prevalence and infection intensity of Endozoicomonas spp. were not driven by environmental stressors. The stressors, however, did appear to impact host health, with high suspended sediment loads and water temperatures of 24°C appeared to be unfavourable to pipi. Overall, Endozoicomonas sp. does not appear to be a main driver in the declining population of pipi from Whangārei and is probably not important to bivalve health. The reduced prevalence and infection intensity of Endozoicomonas sp. in healthy pipi strongly suggests these bacteria are symbiotic. A relationship that has been reported for this bacterial group in species of coral and sponges.
The establishment of a health baseline represents a significant step forward towards biosecurity preparedness by being able to identify changes in infection prevalence and intensity against it. The operational use of these data when paired with historical data will be a powerful tool to identify patterns of disease dynamics and emerging disease.

text: Studies on Paphies australis (Mesodesmatidae) in Whangārei, Aotearoa New Zealand: an investigation into their declining health. Disease outbreaks in marine species can have devastating consequences, including increasing host mortality, destabilising commercial production, altering ecosystem functioning, and jeopardising human health. A changing ocean climate is expected to increase host stress and the risk of disease outbreaks. Particularly through new and emerging diseases and opportunistic infections.
Wild bivalve molluscs provide economic, ecological, and socio-cultural benefits. Healthy and sustainable kaimoana (shellfish/bivalves, seafood) are intrinsically linked to the wellbeing of many communities in New Zealand. Over the past decade there has been a noticeable decline in the general health of native marine bivalves, characterised by an increase in observation of mass die-offs. Reasons for this are not clear and could be due to a number of factors, such as sedimentation, harvesting pressures, or disease. Baseline health data on wild bivalve populations are very rare and therefore it is very difficult to identify the causation of ill health. There is a need to establish health baselines to help benchmark changes in infection prevalence and intensity and identify drivers of bivalve mortality events.
Wild bivalve populations are often located in remote and isolated parts of New Zealand. When a mortality event occurs, the logistics of obtaining quality samples for accurate diagnosis can be hindered due to time delays and sample degradation. To gain a better understanding of these limitations for diagnostics using bacteriology, in Chapter 2 I investigate typical sample collection methods (i.e., samples collected and sent to a testing laboratory) and sample collections immediately in the field to understand what effect different sample methods have on number and types of bacteria isolated. Although the results of Chapter 2 found there were limitations to both sampling methods, it did identify that typical sampling techniques were not wholly optimal, and the information gained by sampling immediately in the field retained additional information that could be essential for disease diagnostics. Field sampling for bacteriology was applied throughout this thesis research.
Pipi (Paphies australis) are native bivalves to New Zealand, inhabiting the shallow subtidal of estuaries and bays. Pipi have suffered serious population declines in an area of northern New Zealand (Whangārei) since 2009. I investigate possible drivers of the poor health of pipi in Whangārei, with the objective of identifying the mechanisms that have contributed to the decline, and prevention of the recovery of pipi in Whangārei, with a primary focus of disease as a causative agent. I establish a health baseline of pipi from Whangārei using histopathology, bacteriology, and qPCR of Endozoicomonas spp., a bacteria previously identified in mortality bivalves (Chapter 3). The health baseline was compared against samples collected during three mass mortality events to help identify drivers of mass mortality events (Chapter 4). Through laboratory experimentation, I test whether pipi exposed to stressors had higher infection intensity and prevalence of Endozoicomonas spp. (Chapter 5). Finally, using archived samples, I test whether the baseline data established was consistent through time and help to provide insights into considerations when analysing bivalve mass mortality events (Chapter 6).
I found that Endozoicomonas spp. make an important part of pipi host microbiome. Although Endozoicomonas spp. are highly prevalent in pipi collected during a mass mortality event, their infection intensity was significantly lower in moribund pipi than healthy pipi. The prevalence and infection intensity of Endozoicomonas spp. were not driven by environmental stressors. The stressors, however, did appear to impact host health, with high suspended sediment loads and water temperatures of 24°C appeared to be unfavourable to pipi. Overall, Endozoicomonas sp. does not appear to be a main driver in the declining population of pipi from Whangārei and is probably not important to bivalve health. The reduced prevalence and infection intensity of Endozoicomonas sp. in healthy pipi strongly suggests these bacteria are symbiotic. A relationship that has been reported for this bacterial group in species of coral and sponges.
The establishment of a health baseline represents a significant step forward towards biosecurity preparedness by being able to identify changes in infection prevalence and intensity against it. The operational use of these data when paired with historical data will be a powerful tool to identify patterns of disease dynamics and emerging disease.

year: 2023