New Zealand Trace Elements Group

Conference 2014 Massey University, Wellington, New Zealand; 30 June - 1 July 2014.

Hosted by Massey University @ Wellington.

Book of Abstracts Compiled & formatted by Peter Robinson & Nick Kim.

web: tracenz.net or tracenz.org

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 1

Table of Contents Session ONE: Trace Elements in the Environment Monica Handler (Victoria University of Wellington). Tracking historic pumice dispersal events through trace element fingerprinting. ...................................................................................................................................5 Tamsin Mitchell (Greater Wellington Regional Council). Arsenic in outdoor air from burning of CCA-treated timber in home fires. .......................................................................................................................................6 Louis Boamponsem (University of Auckland). Transplanted lichens as biomonitors of atmospheric inputs of trace elements in the Auckland Region of New Zealand. ................................................................................7 Nicholas Ling (University of Waikato). Trace element profiling in urban catchments: instantaneous vs integrated matrices and bioavailability. .........................................................................................................8 Niklas Lehto (Lincoln University). Micro-scale oxygen and trace metal dynamics in a sediment mesocosm using a novel DGT-Planar Optode combined sensor. ...............................................................................................9 Jurian Hoogewerff (University of Otago). Elemental and isotope forensic mapping for geographical origin determination. ..............................................................................................................................................10 Adam Hartland (University of Waikato). Phosphorus and arsenic distributions in a seasonally-stratified, ironand manganese-rich lake: microbiological and geochemical controls. ........................................................12 Peter Swedlund (University of Auckland). Thallium geochemistry during acid mine drainage treatment. .......13 Fiona Curran-Cournane (Auckland Council). Trace element pollution within urban green spaces in New Zealand’s largest city. ...................................................................................................................................14

Session TWO: Trace Elements in People Sheila Skeaff (University of Otago). Technical issues in the assessment of iodine status in the New Zealand population. ....................................................................................................................................................17 Louise Brough (Massey University). Iodine and selenium intakes in postmenopausal women in New Zealand after the mandatory fortification of bread with iodised salt. ......................................................................19 Celine Evans (University of Otago). Iodine status in pregnant New Zealand women: are current intakes and recommendations adequate? .......................................................................................................................20 Sally Gaw (University of Canterbury). Does gluten-free mean free of potentially toxic trace elements? ..........21 Andrew Pearson (Ministry for Primary Industries). Characterising dietary polonium exposure. ......................22 Stuart McLaren (Massey University with MBIE). Swallowing hazards of the modern age. ...............................23 J. Robin Fulton (Victoria University of Wellington). Examining the chemistry of soluble divalent lead complexes. ....................................................................................................................................................24 Jonathan Coakley (Centre for Public Health Research @ Massey University). Persistent organic pollutants (POPs) in the New Zealand adult population. ...............................................................................................25 Bruce Croucher (Ministry for the Environment). The Ministry for the Environment’s Contaminated Sites Remediation Fund: a central government initiative to facilitate clean up of the most seriously contaminated orphan sites. (also an intro to Session THREE) ..............................................................................................26

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 2

Session THREE: Contaminated Sites Risk Assessment and Management Dave Bull (Golder Associates). Bioavailability of arsenic and lead at Moanataiari, Thames, New Zealand. ....28 Ben Keet (Geo & Hydro – K8). Development of the ‘Ben Keet Method’ of house dust analysis to identify lead and other heavy metal contaminants. .........................................................................................................29 Andrew Rumsby (Pattle Delamore Partners). Guidance of the use of field-portable XRF (FP-XRF) for contaminated site investigation. ..................................................................................................................31 Jo Cavanagh (Landcare Research). Determining background concentrations of trace elements. .....................32

Session FOUR: Trace Element Contaminants in Agriculture, Part 1 Matthew Taylor (Waikato Regional Council). Fertiliser associated trace elements in 2 transects of soils away from an airfield fertiliser bin sampled 20 years apart. .................................................................................34 Carol Stewart (Joint Centre for Disaster Research, Massey University/GNS Science). Leachable elements in volcanic ashfall: towards improved assessment of health and agricultural hazards. ..................................35 Nick Kim (Massey University). Accumulation and behaviour of fluorine in agricultural soils of two regions: what the field data reveals. ..........................................................................................................................36

Session break: POSTERS Georgina Addae Boamponsem (University of Canterbury). Effect of iron on callus cultures of Solanum tuberosum (potato). ......................................................................................................................................46 Phil Clunies-Ross (Waterways Centre for Freshwater Management, University of Canterbury). Accumulation of trace elements in urban Christchurch waterways. ........................................................................................47 87

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Thalita van Aswegen (University of Otago). Bioavailable strontium isotope ratios ( Sr/ Sr) in European soils – an isoscape for forensic provenancing. ...................................................................................................48 Steve Cameron (University of Waikato). Biological/medical applications of Laser Ablation ICPMS.………………..49 Travis Ancelet (GNS Science). New XRF Capability at GNS Science.....................................................................49 Bill Trompetter (GNS Science). Composition of indoor dust determined by IBA and PIXE. ...............................50

Session FIVE: Trace Elements in Agriculture, Part 2: Special Focus on Cadmium

Cad Gerald Rys (Ministry of Primary Industries). A National Cadmium Management Strategy for New Zealand Agriculture. ...................................................................................................................................................38 Jo Cavanagh (Landcare Research). Cadmium – Where are we at? What do we need? How do we get there? ..39 Ants Roberts (Ravensdown). Cadmium status of New Zealand soils – 2014. .....................................................40 Jo Cavanagh (Landcare Research). Review of models to predict cadmium accumulation in agricultural soils. ..41 Michelle Thunders (Massey University). Sex, Worms, Genes and Cadmium. ....................................................42 Aaron Stafford (Ballance Agri-Nutrients). Spatial variability of soil cadmium in long-term dairy systems. ......43 Shamim Al Mamun (Lincoln University). Municipal compost effectively reduces the transfer of Cd from soil to vegetables. ....................................................................................................................................................44 Jo Cavanagh (Landcare Research). Methodologies for deriving cadmium soil guideline values for the protection of ecological receptors and food standards ..................................................................................................45

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 3

Session ONE: Trace Elements in the Environment Key session phrases & themes: chemistry & behaviour (environmental chemistry; geochemistry), fingerprinting & profiling, monitoring & mapping, baseline determinations, aquatic ecosystems, urban air quality, natural and anthropogenic, forensic science, analytical approaches

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 4

Dr. Monica Handler

Tracking historic pumice dispersal events through trace element fingerprinting Monica R Handlera and Richard J Wysoczanskib a

School of Geography, Environment and Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington: [email protected] b NIWA, Private Bag 14901, Kilbirnie, Wellington

Abstract The Kermadec Arc is a submarine chain of volcanoes stretching some 1500 km north of the Bay of Plenty, NZ. It is host to at least 10 volcanic centres that have erupted pumice. Most recently, Havre Volcano produced about 1.5 km3 material in July 2012, approximately 10 times the volume of the 2010 Eyjafjallajökull eruption in Iceland [Carey et al, 2014]. Pumice from this eruption dispersed 200+ km distance within three weeks. Within six months it had washed up on beaches in New Zealand and Tonga, and a couple of months later in Australia. A characteristic feature of the pumice is that it carries a large number of marine organisms such as large goose barnacles and bryozoans. Remarkably this is the third large pumice raft that has crossed the Tasman in the last decade, spreading marine species endemic to New Zealand and Tongan waters (Bryan et al., 2004: Bryan et al., 2012; Carey et al., 2014). Our understanding of the eruptive histories of these submarine volcanic centres are largely based on dredge sampling during scientific cruises over the past two decades, with material collected generally presumed to have originated from the volcanic edifice that was dredged. The wide dispersion of pumice from the Havre 2012 and earlier Tongan eruptions however, brings this assumption into question. Studies of tephra (ashfall) deposits from comparable on-land eruptives, have shown the power of trace elements to distinguish between eruptions (e.g. Allan et al., 2008). We will apply multi trace element analyses of pumice from Havre 2012, and dredged samples from other centres of the Kermadec Arc – Havre Trough to fingerprint eruptions, ultimately leading to better constraints on the origin of dredged samples, and the dispersal of submarine explosive eruptive products and the marine life they transport across the oceans. References Allan ASR, Baker JA, Carter L & Wysoczanski RJ, 2008. Quaternary Science Reviews 27: 2341-2360 Bryan SE, Cook A, Evans JP, Colls PW, Wells MG, Lawrence MG, Jell JS, Grieg A, & Leslie R, 2004. Earth and Planetary Science Letters 227: 135-154. Bryan SE, Cook AG, Evans JP, Hebden K, Hurrey L, Colls P, Jell JS, Weatherley D & Firn J, 2012. PLoS ONE 7: e40583. Carey RJ, Wysoczanski RJ, Wunderman R, & Jutzeler M, 2014. EOS 95: 157-159.

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 5

Tamsin Mitchell

Arsenic in outdoor air from burning of CCA-treated timber in home fires Tamsin A. Mitchella, Perry K Davyb, and Nick Kimc a

Greater Wellington Regional Council, PO Box 11-646, Wellington: [email protected] b GNS Science, PO Box 30-368, Lower Hutt c Massey University, PO Box 756, Wellington

Abstract Many areas in New Zealand experience poor winter air quality when fine particles in wood smoke arising from home heating fires accumulate during cold and calm overnight temperature inversion conditions. Elemental analysis of airborne particulate matter collected on filters in many NZ residential areas shows a common pattern of elevated concentrations of arsenic during the winter months. The origin of this winter arsenic in air is the suspected burning of timber treated with copper-chrome-arsenate (CCA) preservative in domestic fires. Arsenic concentrations in outdoor air were measured in Wainuiomata, Lower Hutt, using a reference method (high volume air particulate sampling followed by ICP-MS) and the results compared to the national air quality guidelines designed to protect human health. Long term inhalation of inorganic arsenic presents an excess cancer risk to an exposed population. Although the annual average arsenic concentration was almost 30% higher than that recommended by the national air quality guidelines there is only a very small increase in the lifetime cancer risk. There was strong seasonality in arsenic levels with elevated 24-hour concentrations observed during the winter months of 2012 and 2013. The arsenic was present predominantly in the fine fraction of airborne particulate matter (PM2.5) which is emitted by home fires. The observed variation in daily arsenic concentration during the winter months was consistent with what would be expected from the intermittent burning of CCAtreated timber by some local residents. The potential for additional adverse health impacts from short term exposure to arsenic at the peak levels observed during the winter months and for people who burn CCA-treated timber inside their homes needs further investigation.

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Louis Boamponsem

Transplanted lichens as biomonitors of atmospheric inputs of trace elements in the Auckland Region of New Zealand Louis K. Boamponsem, C.R. de Freitas School of Environment, University of Auckland, PB 92019, Auckland: [email protected]

Abstract Some lichens species can provide environmental archives of atmospheric deposition of trace elements that can be investigated as records of environmental change. In this way, lichens can be useful as biomonitors of air pollution. The data they provide can add to the spatial detail not always available from more sophisticated and therefore more expensive instrumental air pollution monitoring networks. However, the use of lichens for air quality assessment in New Zealand has not been widely explored. Due to this lack of attention, there is no lichen species that has been formally validated for use locally as an air pollution biomonitor; although several species have been identified as being potentially useful. The most promising of these is Parmotrema reticulatum. This study assesses the effectiveness of this species as a biomonitor of atmospheric trace element deposition in Auckland. Data were collected over the period August 2013 to February 2014 from a total of 21 different sites. One a month, lichen were transplanted from a reference ‘clean site’ outside the Auckland urban area at Patumahoe to 20 sampling sites at the central business district of Auckland city. The transplanted lichen samples were exposed for a period of one month. At the end of each exposure period, the samples were retrieved for elemental analysis using the inductively coupled plasma mass spectrometry (ICP-MS) technique. The elements that were measured in the lichen samples are arsenic, aluminium, antimony, cadmium, copper, chromium, cobalt, iron, manganese, magnesium, nickel, lead, vanadium, thorium and zinc. The results showed significantly consistent elevated average monthly concentration of each monitored element in the lichen samples from the sampling stations in excess of the background values. P. reticulatum may therefore be valuable for future trace element biomonitoring in Auckland. Future research will aim to identify the major origins and source profiles of key elements in lichen thalli in the Auckland area and to calibrate the quality of the lichen data so as to be able to certify the reliability of the method used. Information on the usefulness of P. reticulatum in biomonitoring would be useful in monitoring environmental impacts in areas where new industrial development is being contemplated or for monitoring recovery in areas where remediation is being attempted. It could also be useful in future baseline air quality studies in New Zealand. The method developed along with lichen performance validation would allow for detailed spatial air pollution data for the greater Auckland area to be assembled, as opposed to relying on a few point-source measurements as it currently the case. It will be possible to monitor sites where it is not possible to locate air samplers and thereby overcome issues of cost, security of equipment and problems of access. Data collected will improve Auckland Council’s assessments of air pollution in the Auckland region through identification of pollution sources and improved spatial coverage.

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 7

Assoc. Prof. Nicholas Ling

Trace element profiling in urban catchments: instantaneous vs integrated matrices and bioavailability Nicholas Linga, Tammy Vallera, Susan Clearwaterb and Kevin Colliera a

School of Science, The University of Waikato, Private Bag 3105, Hamilton: [email protected] b NIWA, P.O. Box 11115, Hamilton

Abstract Urbanised environments generate specific environmental contaminants depending on their principal land use (e.g. recreational, residential, industrial) and discharge soluble contaminants from their catchments into streams. Water-borne contaminants therefore serve as a useful measure of discharge rate (source) whereas other components of streams (sediments and biota) provide potentially useful measures of in-stream accumulation (integrating sinks and bioavailability, respectively). We measured elemental profiles of water, stream-bed sediment and biota (shortfin eel tissue) in several catchments of Hamilton City that differ in total catchment area and land use. Overall, levels of potentially toxic metals and metalloids were low and rarely exceeded ANZECC guidelines although the Waitawhiriwhiri catchment showed the greatest potential for generating significant contaminant discharge due to a high proportion of industrial land use, high relative impervious surface, and discharge from Hamilton Lake (Rotoroa) containing high levels of As (an historic legacy). Sampling stormwater discharge following dry spells demonstrated significant increases in contaminant concentrations and total contaminant discharge (up to 165-fold) relative to base-flow conditions. Sediment sampling revealed the potentially extreme patchiness of contaminant sources and sediment sinks. Tissues from shortfin eels were an important measure of contaminant bioavailability given their long residence time and high site fidelity within a catchment, however, elemental profiles of eel tissue did not correlate well with those of catchment sediments, especially for the principal urban catchment metals Cu and Zn, possibly due to physiological regulation of these metals. Of note, however, were very high levels of Cd in eels sampled from an entirely rural Waikato catchment. Each of the matrices examined (water, sediment, biota) revealed differing dynamics of catchment derived elemental contaminants.

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 8

Dr. Niklas Lehto

Micro-scale Oxygen and Trace Metal Dynamics in a Sediment Mesocosm using a Novel DGT-Planar Optode Combined Sensor Niklas J. Lehtoa, Morten Larsenb, William Davisonc, Hao Zhangc and Ronnie N. Gludb a

b

Department of Soil and Physical Sciences, Lincoln University, PO Box 85084, Lincoln 7647: [email protected]

Institute of Biology and Nordic Center for Earth Evolution (NordCEE), University of Southern Denmark, Odense, Denmark c

Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK

Abstract Measurements of trace metal supply and dissolved oxygen concentrations were carried out in an experimental sediment mesocosm using a novel combined sensor. The sensor is composed of an oxygen sensitive planar optode overlain by an ultra-thin DGT (diffusive gradient in thin-films) and allows for simultaneous high resolution measurements of trace metals and O2 in two dimensions. Three types of sediment features were investigated: (1) the sediment-water interface (SWI); (2) an area featuring the mineralisation of an artificially introduced aggregate of organic matter at the SWI; (3) small areas of increased trace metal supply ~13 mm below the SWI. At the SWI, a steady decrease in the oxygen penetration depth was observed during the deployment. This corresponded to an increased supply of Fe and other trace elements to the DGT. At the location of the aggregates, after an initial lag period, rapid depletion of oxygen was observed resulting in a distinct anoxic feature at the sediment surface. At this location the DGT measured a large increase in the availability of Cu, Fe, Mn and Pb, but a decrease in the supply of Co, Ni and Zn. An increased availability of all measured trace metals (Co, Cu, Fe, Mn, Ni, Pb and Zn) was observed at the subsurface microniches, without any observed changes in oxygen concentrations. The oxygen depletion and reduction in Co, Ni and Zn availability at the SWI is believed to be caused by a rapid growth in microbial populations, stimulated by the presence of reactive organic material, resulting in a localized sink for these metals. Distinct differences in the availability of trace metal between the various microniches indicate the presence of various processes involved in elemental cycling within a small area of sediment. The results highlight the importance of techniques that can provide high resolution measurements of multiple analytes simultaneously in developing the understanding of dynamic heterogeneous environments. The use of the combined sensor for investigating pH, oxygen and trace metal dynamics in a plant rhizosphere is also briefly presented.

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Assoc. Prof. Jurian Hoogewerff

Elemental and Isotope Forensic Mapping for Geographical Origin Determination Jurian A. Hoogewerff and Shaerii Sarker Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9016, New Zealand: [email protected]

Isotope maps, or isoscapes, have shown to be valuable for the study of the origin and migration of natural materials and organisms. The potential of using this information not only for scientific pursuits but also to aid forensic investigations was realized early on. However when porting scientific results to real world applications with potential serious consequences for those investigated, the scientific models need to be properly validated. Essential for use in law enforcement is that any outcome should be presented in such a manner that jurors, lawyers and law enforcement officers can make proper use of the statements made. Scientifically it has become evident that the hydrogen and oxygen isotopic composition of rainwater is related to a limited number of well-understood spatial parameters. Models of the hydrogen and oxygen isotopic composition in precipitation have been validated globally and now the regional composition of groundwater and food products can be predicted with a useful level of accuracy, enabling discrimination of latitudinal distances in the 200km range. To increase spatial discrimination other parameters that can be linked to existing information already captured in maps, e.g. existing geochemical stream-sediment and soil maps and the associated samples, provide a useful starting point. Recent research has shown that especially the radiogenic isotopic composition of elements like strontium and lead in soil can be linked to the isotopic composition of a local foodweb. The often relatively well-understood behavior of these isotope systems allows researchers to make spatial predictions of the isotopic profiles in target tissues and objects. The first example to be presented at TRACENZ concerns the provenancing of seized cannabis to gather intelligence about production region and trafficking routes. In order to circumvent the logistical challenges of obtaining a spatially representative background population of cannabis grown in New Zealand we have investigated the potential of using blackberry as a spatial proxy as it is found throughout NZ. Both cannabis and blackberry belong to the same botanical order of Rosales. Our basic assumption was that variations in geological and climatic conditions create comparable variable isotopic signatures in both plants. Blackberry leaves have been collected at 130 locations on the North and South Islands. In addition we received cannabis samples from Kaitaia, Hawkes bay, Nelson and Dunedin through ESR and New Zealand police. The hydrogen isotopic values of blackberry have been compared with the isotopic composition of precipitation using a NZ specific d 2H precipitation model based on the NZ Virtual Climate Station Network (VSCN-NIWA). The cannabis results show a good correlation with both the measured and predicted blackberry results thus indicating that model can be used as a provenancing tool for cannabis. [Continued overleaf...] NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 10

[Continued...] The second example is related to a cold case in the south of the UK where a beheaded and “behanded” torso was discovered in 1991 and buried as unidentified in 1994. Exhumation and elemental and isotopic analysis in 2010 gave the cold case investigators the necessary information to reinitiate the search for the origin of the victim. The presentation will explain and demonstrate how the different elemental and isotopic maps are combined to construct spatial likelihood models that are scientifically correct, provide a tool for investigators and suit the legal process.

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Dr. Adam Hartland

Phosphorus and arsenic distributions in a seasonally-stratified, ironand manganese-rich lake: microbiological and geochemical controls Adam Hartlanda, Martin S. Andersenb, and David P. Hamiltona a

Environmental Research Institute, School of Science, Faculty of Science and Engineering, University of Waikato, Hamilton, 3432: [email protected] b Connected Waters Initiative Research Centre, UNSW Australia, 110 King Street, Manly Vale, NSW 2093, Australia

Abstract Seasonal stratification in temperate lakes greater than a few metres deep provides conditions amenable to pronounced vertical zonation of redox chemistry. Such changes are particularly evident in eutrophic systems where high phytoplankton biomass often leads to seasonally-established anoxic hypolimnia and profound changes in geochemical conditions. In this study, we investigated the behaviour of trace elements in the water column of a seasonally-stratified, eutrophic lake. Two consecutive years of data from Lake Ngapouri, North Island, New Zealand, demonstrate the occurrence of highly correlated profiles of phosphorus (P), arsenic (As), iron (Fe) and manganese (Mn), all of which increased in concentration by 1-2 orders of magnitude within the anoxic hypolimnion. Stoichiometric and mass-balance considerations demonstrate that increases in alkalinity in hypolimnetic waters were consistent with observed changes in sulfate, Fe and Mn concentrations with depth, corresponding to dissimilatory reduction of sulfate, Fe(III) and Mn(IV) hydroxides. Thermodynamic constraints on Fe, Mn and Al solubility indicate that amorphous Fe(III), Mn(IV) hydroxides most probably controlled Fe and Mn in the surface mixed layer (~0 to 8 m) while Al(III) hydroxides were supersaturated throughout the entire system. Surface complexation modelling indicated that iron hydroxides (HFO) potentially dominated As speciation in the lake, but only if other colloidal phases such as allophanic clays capable of limiting free PO4 activity, were present. This research highlights the coupling of P, As, Fe and Mn in Lake Ngapouri, and the apparent role of multiple colloidal phases in affecting P and As activity within overarching microbiological and geochemical processes.

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 12

Dr. Peter J. Swedlund

Thallium Geochemistry During Acid Mine Drainage Treatment Katherine Coupa, James Popeb, Peter J Swedlunda and Paul Weberc and Christopher Weisenerd a

School of Chemical Sciences, University of Auckland, New Zealand: [email protected] b CRL Energy Ltd, PO Box 29-415, Christchurch, New Zealand c O'Kane Consultants (NZ) Ltd, PO Box 8257, Christchurch 8440, New Zealand d Earth and Environmental Sciences, University Of Windsor, Ontario, Canada

Abstract Thallium (Tl) is a toxic Group 13 element which can be an environmental issue in some acid mine drainage (AMD) systems. Thallium can enter AMD systems either directly from sulfide oxidation or indirectly if it has become concentrated in acid neutralising materials used to treat AMD. The use of industrial waste materials as cost effective neutralents for AMD needs to be tempered by an understanding of the impact of these wastes on trace metal loadings that leave the AMD treatment system. Thallium exists in aquatic systems predominantly as the highly soluble monovalent cation with a 1 st hydrolysis constant of 10-13 but it can form an insoluble trivalent species at high EH. The monovalent Tl+ is expected to be very mobile in AMD systems and, unlike other toxic cations such as Pb +2 and Cu+2, will have a low affinity for the surfaces of both Fe +3 and Al+3 hydrous oxides that precipitate during neutralization treatments. This means that there is a need for extra caution with regards to the thallium content of AMD neutralents. In this work we explore the geochemistry of Tl during laboratory scale AMD neutralization experiments with a focus on a waste Ca(OH)2 product with a known elevated level of Tl.

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 13

Dr. Fiona Curran-Cournane

Trace element pollution within urban green spaces in New Zealand’s largest city Fiona Curran-Cournanea, Gavin Learb, and Luitgard Schwendenmannb a

Auckland Council, 1 The Strand, Takapuna 0622, Auckland: [email protected] b Auckland University, 3a Symonds Street, Auckland 1010

Abstract Trace elements are naturally present in soils which are, amongst other sources, inherited from parent material. However, soils can be dramatically influenced by human activity and urban soils in particular can result in high levels of heavy metals originating from vehicle emissions, coal and fuel combustion, past and current use of fertilisers and pesticides and other anthropogenic activities. This can pose significant environmental as well as human health risk. Auckland is the largest city in New Zealand with a population of about 1.5 million at 2012. The population is projected to reach 2.5 million by 2040 which could potentially further exacerbate the impact of anthropogenic activity on the soil environment. It is therefore of vital importance that we monitor levels of potential pollutants within our urban soils to better understand the likely implications for both human and environmental health. The objective of this study is to determine trace elements across urban Auckland, with a particular focus on As, Cd, Cr, Cu, Pb, Hg, Ni and Zn. Sixty green spaces were chosen and categorised by their vicinity to or within forests, high traffic zones, industrial areas, parks, residential and school areas. Soil samples were collected at both the 0-10 and 10-30 cm soil depths to determine if heavy metals were largely restricted to surface soil. Trace elements were measured both on a gravimetric and volumetric basis to account for the inherent physical properties of soil type to get a true understanding of the level of trace element pollution in surface soils using a pollution index. No significant differences were observed when comparing concentrations (mg/kg) of trace elements at soil depths in the present study. Significant differences were observed for all trace elements for site category with forest sites having the least levels of trace elements for all analytes suggesting that forest canopy cover was an effective buffer protecting against the aerial deposition of these metals onto soils. Levels of Cr, Cu, Ni and Zn were greatest for high traffic sites, Cd and Hg greatest for parks, As greatest for schools, and Pb greatest for industrial sites. Principle component analysis (PCA) indicated that the first component accounted for almost 54% of the total variance and with the second component explaining a further 18% of variance in the data.

[Continued overleaf...]

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 14

[Continued...] As well as the PCA clearly distinguishing forest sites as having the least levels of trace elements, using regionally available geological maps volcanically derived soils were also distinguishable and were associated with high levels of Cr and Ni. Multivariate dispersion analysis also determined the least dispersion value for forest sites (0.753) indicating that levels of trace elements were least dispersed for this site category. This was followed by values of 0.847, 0.861, 0.922, 1.302 and 1.315 for parks, schools, residential, high traffic and industrial sites, respectively. It was considered appropriate that forest sites act as a contextual indicator for background conditions within an urban setting for the purposes of a pollution index. The mean pollution index (PI) calculated according to these forest sites, using soil samples collected at the 0-10 cm depth for the remaining sites, was classified as high (PI > 3) for Cd, Cu and Ni, indicating that levels of heavy metal for these parameters were more than three times greater than levels recorded at forest sites. Moderate PI’s (1 < PI ≤ 3) were calculated for As, Cr, Pb, Hg and Zn, and no mean PI’s were classified as low (PI ≤ 1). When PI’s were pooled and averaged the mean integrated pollution index (IPI) was deemed high at 3.3 (range 0.4-9.1) indicating high levels of pollution. Data collected in this study provides spatial trace element soil information across New Zealand’s largest city for the first time which can be used to provide vital baseline information for future long term studies. It is also recommended that monitoring of trace elements at these sites is repeated in the future to determine if levels elevate over time.

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 15

Session TWO: Trace Elements in People Key session phrases & themes: dietary intakes, iodine, selenium, polonium, gluten-free, magnets, button batteries, population exposures, and POPs (Persistent Organic Pollutants) as honorary trace elements, introduction to managing risks from contaminated sites (central government remediation initiatives)

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 16

Assoc. Prof. Sheila Skeaff

Technical issues in the assessment of iodine status in the New Zealand population Sheila A Skeaff Department of Human Nutrition, University of Otago, PO Box 56, Dunedin 9054: [email protected]

Abstract Background: Mild to moderate iodine deficiency was first reported in New Zealand in the early 20th century although there are anecdotal reports of goitre in Māori in the 19th century. The fortification of table salt in 1939 and use of iodophors in the dairy industry in the 1960s improved intakes resulting in good status from the 1950s-1980s. However, changing food patterns and the replacement of iodophors with detergent-based sanitisers resulted in the re-emergence of mild iodine deficiency in the 1990s. In order to increase iodine intakes, the New Zealand government introduced the mandatory fortification of bread with iodised salt in 2009. Subsequent research has reported that iodine status has improved in children but data on adults is inconclusive. The rise and fall in iodine intakes over the last 100 years indicates that New Zealand needs to regularly monitor status of its population. Objective: The aim of this presentation is to outline the methods used to assess iodine status in populations including an overview of their advantages and disadvantages. Discussion: Iodine status can be assessed in humans using a variety of biochemical, dietary, and clinical indices. Biochemical assessment can include the measurement of the iodinecontaining thyroid hormones in blood samples. However, in populations with mild iodine deficiency such as New Zealand, the concentration of thyroid hormones typically fall within normal reference ranges thus thyroid hormones are considered insensitive indices of iodine status. Because ~90% of dietary iodine is excreted in the urine, the most commonly used index to assess iodine status is the median urinary iodine concentration (UIC) (reported as μg/L) of a spot or casual urine sample collected from at least 30 people. This value is then compared against recommended cut-offs published by the World Health Organisation (WHO). The large intra- and inter-individual variation associated with UIC means that it cannot be used to measure iodine status in an individual. It is also possible to collect 24hour urine samples although issues with compliance and respondent burden limit their practicality for large numbers of people. UIC can be determined in 24-hour samples but there are currently no WHO cut-offs specific to 24-hour urine samples, which is particularly important for adults with mean 24-hour urine volumes of 1.5-2.5 L. The 24-hour urine sample can, however, provide a relatively accurate measure of daily iodine intake. This is useful because assessing the iodine content of the diet is problematic as it is difficult to measure the contribution of iodised salt, used at the table or in cooking, to total iodine intake. [Continued overleaf...] NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 17

[Continued...] Not surprisingly there are few studies worldwide that have assessed iodine intakes and most of these would typically underestimate the amount of iodine consumed. Nonetheless, measuring the iodine content of foods and the diet is important as this information is needed to model the impact of food fortification or changes to the diet on iodine intakes. In addition to urine and diet, iodine status can also be assessed clinically by measuring the prevalence of goitre (i.e. enlarged thyroid gland) in the population; this requires access to an ultrasound machine and a trained health professional that limits its routine application. Conclusion: Currently, regardless of the method used, the accurate assessment of iodine status of the population, particularly adults, requires careful consideration and interpretation; it is still not possible to assess iodine status in an individual. This is of concern because iodine deficiency can affect brain development and cognition. Promising new methods to assess iodine status are currently being studied.

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 18

Dr. Louise Brough

Iodine and Selenium Intakes in Postmenopausal Women in New Zealand after the Mandatory Fortification of Bread with Iodised Salt Louise Brougha, Caroline Gunnb, Ying Jina, Jane Coada, Janet Webera and Marlena Krugera a

Institute of Food, Nutrition and Human Health, Massey University, Palmerston North Gravida: National Centre for Growth and Development, The University of Auckland, Auckland

b

Abstract Introduction: There are low levels of both iodine and selenium in the New Zealand food supply. The New Zealand Total Diet Survey (TDS) 2003-4 estimated the mean dietary exposure for iodine was 60 µg/day (below the Estimated Average Requirement (EAR) of 100 µg/day) and for selenium was 49 µg/day (similar to the EAR of 50 µg/day). Food Standards Australia and New Zealand introduced the mandatory fortification of all bread (except organic) with iodised salt in Australia and New Zealand in September 2009 to prevent iodine deficiency. Aims: To assess iodine and selenium intake among a self-selecting sample of postmenopausal women in Palmerston North, Hawkes Bay and Auckland after the mandatory fortification of bread with iodised salt. Methods: In 2011, 95 postmenopausal women (aged 50 to 70 years) provided a sample of urine collected over 24 hours. Iodine and selenium concentrations in urine samples were determined by an accredited commercial laboratory (Hill Laboratories, Hamilton, New Zealand) using inductively-coupled plasma mass spectrometry. Iodine and selenium intakes were estimated by extrapolation of 24 hour urinary iodine and selenium excretion based on the estimated amounts excreted via urine (90% and 55% of daily intake, respectively). The data were analysed using IBM SPSS version 20. Non parametric data are represented by median and IQR and parametric data by mean and standard deviation. Results: The median urinary iodine concentration (UIC) was 56 (41, 78) µg/L, which according to WHO criteria indicate the population had mild deficiency. Mean urine volume was 2.1 (± 0.7) L and median estimated iodine intake was 136 (100, 168) µg/day, well above the EAR, with only 26% of participants below the EAR. Estimated intakes indicate the population has a high probability of adequacy of intake. Estimated iodine intakes were much higher than the 2003-4 TDS indicating an increase in intake of iodine, which is most likely due to the mandatory fortification of bread with iodised salt. Estimated median selenium intake was 49 µg/day (36, 67), the same as seen in the 2003-4 TDS and similar to the EAR, suggesting that dietary intake of selenium is close to adequacy for the study population. Iodine and selenium intakes were weakly correlated (p=0.001, r=0.342). Conclusions: The mandatory fortification of bread with iodised salt appears to have improved iodine intake in this study population. However, there is some controversy over whether this population is still iodine deficient. WHO population cut-offs for iodine need to be re-evaluated to ensure deficiency is not over estimated. Selenium intake appears to be adequate for this population, however, some individuals may still have suboptimal intakes. NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 19

Celine Evans

Iodine status in pregnant New Zealand women: Are current intakes and recommendations adequate? Celine L Evans, Abbey L Billing, Cheri Chiu, Sheila A Skeaff Department of Human Nutrition, University of Otago, PO Box 56, Dunedin 9054: [email protected]

Abstract Background: Iodine requirements increase in pregnancy as both the mother and fetus need iodine for the synthesis of thyroid hormones. In response to a re-emergence of iodine deficiency in New Zealand in the 1990s, bread was fortified with iodised salt in 2009 and a recommendation for a daily supplement of 150 µg iodine in pregnancy has been in place since 2010. Objectives: The aim of this study was to assess iodine status of pregnant women to determine the effectiveness of both fortification and supplementation in achieving adequate iodine status. Methods: A convenience sample of 100 pregnant women was recruited from each of three cities (Dunedin, Hamilton and Wellington) between July 2012 to December 2013. Women were asked to collect a spot urine sample to determine urinary iodine concentration (UIC), and complete a questionnaire to obtain socio-demographic information, iodine supplement use, and frequency of consumption of iodine containing foods. Results: The final sample size was 302 women with a mean age of 31±5 years of the following ethnicity: 87% NZ European and other ethnicities, 13% Māori and Pacific Island. The median UIC was 105 µg/L; this falls below 150-250 µg/L suggested by the World Health Organization for adequate iodine status in pregnancy. Despite the recommendation for daily iodine supplementation, 35% of women did not take an iodine supplement. The median iodine intakes from food alone, food including salt use, and total iodine intake including an iodine supplement were 76 µg/day, 113 µg/day and 236 µg/day, respectively. The estimated average requirement (EAR) of iodine in pregnant women is 160 µg/day; the food frequency questionnaire estimated that 61% of women met the EAR when iodine intake included iodine from supplements and discretionary salt while only 1% of women met the EAR without the supplement. Iodine supplementation was a significant predictor of UIC (p=0.048) in multivariate analysis linear regression. Ethnicity and income were significant predictors of total iodine intake (p=0.009 and p=0.011, respectively). Conclusions: This study indicates that although fortification and supplementation has improved iodine status in pregnant women (from 38 µg/L in 2005 to 105 µg/L in 2013), these data suggest that pregnant women in New Zealand still have sub-optimal iodine status. Further research is needed to ascertain whether an iodine supplement with a higher dose of iodine would improve iodine status. Based on the relatively high percentage of women who did not take an iodine supplement, assessing the current practices of healthcare providers regarding the provision of iodine education to their patients may be beneficial.

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 20

Dr. Sally Gaw

Does gluten-free mean free of potentially toxic trace elements? Hamish Rossa, Ellen Ashmoreb and Sally Gawa a

b

Department of Chemistry, University of Canterbury Institute of Environmental Science and Research Ltd (ESR), Christchurch Science Centre

Abstract Increasing numbers of people are choosing to consume a gluten free diet. Cereals can be a significant dietary source of trace element exposure. There is currently very limited data on the potentially toxic element concentrations in cereals other than wheat and rice. A pilot study of gluten free cereals commercially available in New Zealand was undertaken to determine if a gluten free diet alters dietary exposure to arsenic, cadmium and lead. Ten different gluten free flours were tested along with wheat flour as a comparison. The eleven flours were white wheat, white rice, buckwheat, quinoa, soy, millet, cornmeal, cornflour, tapioca, gluten free blends, and potato starch. The four samples were purchased from supermarkets and health food shops in Christchurch and Auckland, New Zealand. Arsenic was detected in rice flour and gluten free flour blends at concentrations up to 483 µg kg-1. Cadmium was the element most frequently detected with the highest concentrations detected in buckwheat flour (84 µg kg-1). Lead was only detected in four samples at a maximum concentration of 97 µg kg-1. Gluten free diets can be heavily reliant on rice as a source of carbohydrates. A second project investigated the concentrations of arsenic, cadmium and lead in rice commercially available in New Zealand. Seven rice varieties were investigated including arborio, basmati, brown, jasmine, long grain, short grain and sushi. There were significant differences in trace element concentrations between the different rice varieties. The highest concentrations of cadmium were measured in arborio rice whereas the highest concentrations of arsenic and lead were measured in brown and basmati rice respectively. A risk assessment for arsenic, cadmium and lead exposure from adherence to a gluten free diet will be presented.

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 21

Andrew Pearson

Characterising dietary polonium exposure Andrew Pearsona, Sally Gawb, Nikolaus Hermanspahnc and Chris Gloverb a

Ministry for Primary Industries, PO Box 2536, Wellington: [email protected] b University of Canterbury, Private Bag 4800, Christchurch 8140 c Environmental Science & Research, PO Box 29-181 Christchurch 8540

Abstract Potential exposure to radioactive isotopes through the diet has received international focus following the accident at Fukushima-Daiichi. However, the greatest exposure for the New Zealand population comes from ingestion of naturally occurring radioactive isotopes, for example, polonium 210. Decay of the primordial nuclide uranium 238 leads to the presence of a number of daughter radionuclides in the environment, the penultimate daughter isotope being polonium 210, the longest lived natural polonium isotope with a half-life of 138 days, and one of the most radiotoxic natural isotopes. It can enter marine and terrestrial food chains as polonium is mobile in the environment and accumulate in certain foods. Polonium 210 can contribute to natural ionising radiation exposure as it has high specific activity and decays with a strong alpha particle. Anthropogenic activities including fossil fuel use and agriculture can increase levels of natural radionuclides, including polonium 210, in the environment consequently increasing dietary exposure over time. To identify future potential increases, baseline data for current ranges of radionuclides in the diet and exposures is crucial. A survey of polonium 210 activity across the New Zealand diet was conducted, complemented by a targeted seafood survey that investigated if there are any significant variations in polonium 210 concentrations/activities between fishing regions and seafood species. The surveys identified that terrestrial food sources commonly contain less than 0.5Bq/kg polonium. In contrast, seafood can accumulate the isotope to a greater degree, with the highest levels of polonium occurring in shellfish at up to 30 Bq/kg. Regional variation in levels was not significant with most fish species across all fishing regions containing approximately 2 Bq/kg. Benthic species however accumulated higher levels. The results of these surveys have been used to calculate the ionising radiation dose resulting from polonium 210 in the diet. Seafood was identified as the primary source of polonium 210 exposure in the New Zealand diet. Polonium is calculated to be a significant contributor to the total dose of radioactivity; however the overall exposure to consumers of radionuclides in the diet is within normal background levels.

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 22

Dr. Stuart McLaren

Swallowing hazards of the modern age Stuart J McLarena and Lou Parkerb a

b

College of Health, Massey University, Wellington Trading Standards, Ministry of Business, Innovation and Employment, Wellington.

Abstract Among the greatest swallowing hazards for small children in the modern age are the proliferation of small button batteries and the permanent rare earth magnets which are used as toys. The rare earth magnets come in two classes: neodymium – iron – boron and samarium – cobalt. Such devices are often not kept secure in the home. Spent items are often discarded in the general refuse without any special care. This means that these items are often accessible to young children to pick up, put in their mouths and swallow. One of the greatest dangers is for button batteries large enough to become stuck or lodge in the oesophagus. An electrolytic reaction is established with the saline content of salvia and this results in the production of hydroxide and chlorine at the respective electrodes. There have been serious caustic burns from these devices if they are not discovered quickly and removed. The magnets are so powerful that they can attract each other across the intestine walls and cause perforations and necrosis. There are cases where major surgery is the only option once the ingestion and location are discovered. One of the major issues is that young children while distressed are not able to often tell their carers what has happened to them and present with a variety of symptoms which can easily be misdiagnosed. As medical clinics don’t have X-ray facilities on hand, it often means admission to accident and emergency departments and X-ray to determine the presence and location of these items in the body. Trading Standards recently imposed a total ban on the sale of small high powered magnets in New Zealand. The situation is more difficult for button batteries as these have a genuine and important use in modern society and some other strategies are needed to minimise the harm from these units. Some researchers and responsible manufacturers have been investigating various alerting ingredients such as dye which will be realised in the mouth once the battery is ingested. Others have included child proof packages which would prevent a young child from opening the package. However this does not preclude used batteries which are accessible to young children or cheap batteries

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 23

Dr. J. Robin Fulton

Examining the chemistry of soluble divalent lead complexes J. Robin Fulton a

School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington: [email protected]

Abstract Divalent lead is capable of modulating the pKa of coordinated water molecules such that lead-hydroxides predominate at biologically relevant pH’s. This has important implications when considering the biochemical pathways of lead poisoning as these hydroxides can potentially act as either a base and deprotonate weak acids, or as a nucleophile towards electrophilic substrates. Although this reactivity has been directly implicated in the leadinduced cleavage of RNA, it is viable that this activity might be relevant to other pathways in lead poisoning. However, because of their limited solubility, the solution phase chemistry of lead(II) hydroxides has largely been ignored. We have generated a series of soluble lead hydroxide model systems to explore their potential reactivity towards both acidic and electrophilic substrates. These complexes were found to be only weakly basic and have limited reactivity with aliphatic electrophilic substrates. However, these complexes are exceedingly reactive with unsaturated electrophiles such as carbon dioxide. Comparisons with both zinc and tin complexes have revealed that this reactivity is in part due to the Lewis acidic behavior of the metal center. Implications towards biological activity will be discussed. Ar N N Pb Ar I

+ Me

I

- Me OR

Ar Pb N N O R Ar R = iPr, sBu, tBu

O C O

Ar N N Pb Ar O O

R

O

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 24

Jonathan Coakley

Persistent organic pollutants (POPs) in the New Zealand adult population Coakley, J.a*, Mannetje, A.a, Bates, M.b, Borman, B.a, Douwes, J.a a

b

Centre for Public Health Research, Massey University, Wellington, New Zealand Epidemiology and Environmental Health Sciences, University of California, Berkeley, USA *Corresponding author: [email protected]

Abstract This study determined the concentrations of persistent organic pollutants (POPs) in the serum of a representative sample of adult New Zealanders. POPs determined in this study include polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), brominated flame retardants (BFRs) and perfluorinated compounds (PFCs). Serum samples (n=747) were collected over the period May 2011 and April 2013. Individual samples were pooled according to groups based on age, gender, ethnicity (Māori and non-Māori), and geographic region. POPs in serum were measured using gas chromatography-high-resolution mass spectrometry (GC-HRMS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The weighted mean serum PCDD/F and PCB concentrations were 5.81 and 1.54 pg TEQ05/g lipid, respectively, and increased with age. Of the quantified OCPs, the highest serum concentrations were determined for p,p’-DDE (weighted mean = 250 ng/g lipid) followed by the beta-HCH (12.9 ng/g lipid), hexachlorobenzene (7.62 ng/g lipid) and dieldrin (5.22 ng/g lipid), and generally increased with age. Of the quantified BFRs, the highest serum concentrations were observed for BDE209, (weighted mean = 3.57 ng/g lipid), followed by BDE47 (2.15 ng/g lipid), BDE153 (1.34 ng/g lipid) and BDE99 (1.02 ng/g lipid). In contrast with the PCDD/Fs, PCBs and OCPs, the highest serum BFR concentrations were observed in the youngest age groups. Of the four detected PFCs the highest serum concentrations were determined for perfluorooctanesulfonic acid (PFOS) (weighted mean = 3.59 ng/mL), followed by perfluorooctanoic acid (PFOA) (2.51 ng/mL), perfluorohexane sulfonate (PFHxS) (1.24 ng/mL) and perfluorononanoic acid (PFNA) (0.69 ng/mL). Serum concentrations of PFCs increased with age. For most POPs there was no evidence that serum concentrations differed between geographic regions, while for p,p’-DDE serum concentrations were higher in the south compared to the north of New Zealand. There was no evidence that serum concentrations differed between Māori and non-Māori. Serum concentrations of dieldrin, mirex, BFRs and PFCs were higher in males compared to females. When comparing serum concentrations with those determined for the New Zealand population 15 years earlier, a reduction over time was evident for the chlorinated POPs (PCDD/Fs, PCBs and OCPs). New Zealanders’ serum concentrations of PCDD/Fs and PCBs are low by international comparison, while for OCPs they are similar or lower compared to those reported for other developed countries. This study provides valuable information to assess the exposure of New Zealanders to this group of environmental pollutants.

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 25

Bruce Croucher

The Ministry for the Environment’s Contaminated Sites Remediation Fund Bruce Croucher Ministry for the Environment, PO Box 10362, Wellington 6143

Abstract

Bruce will be providing an outline about the Contaminated Sites Remediation Fund and what it has been used for, including some of the heavy metal contaminated sites that have been (or are going to be) investigated or remediated financed with support from central government.

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 26

Session THREE: Contaminated Sites Risk Assessment and Management Key session phrases & themes: contaminated sites investigation, risk assessment, remediation and management, human health protection, sitespecific guidelines, sampling approaches, site-specific investigation, high concentration soil and dust contamination

NZ Trace Elements Group Conference 2014, Massey University, Wellington, 30 June - 1 July, 2014 27

Dr. Dave Bull

Bioavailability of arsenic and lead at Moanataiari, Thames, New Zealand Dave Bull,a Simon Hunt,a Sue Robinsonb a

b

Golder Associates (NZ) Limited, 93 The Terrace, Wellington 6011: [email protected] Golder Associates Incorporated, 18300 NE Union Hill Road, Redmond, Washington 98052, USA

Abstract Moanataiari is a subdivision in Thames township, New Zealand. Built on land reclaimed from the Firth of Thames using mine waste from the 1860s Coromandel gold rush overlain by soil from the hills where mining took place, many residential properties in Moanataiari contain elevated concentrations of arsenic and lead in soil. Almost every property exceeds national soil contaminant standards. But this was not discovered until 2011 – leaving more than 200 households facing health fears, losses in home values and the prospect of extensive remediation. Given that generic soil contaminant standards in New Zealand are intended to be protective of all sites in New Zealand, their derivation is intentionally conservative. Golder recognized that arsenic and lead at Moanataiari were likely to have relatively low bioavailability, due to their geological origins. Following agreement with local regulatory agencies, Golder conducted bioaccessibility testing in collaboration with RJ Hill Laboratories, using the US EPA relative bioaccessibility leaching procedure (RBALP). The RBALP was developed and validated for estimating relative Pb bioavailability in