Long-term Exposure to Low Air Pollutant Concentrations and the Relationship with All-Cause Mortality and Stroke in Older Men.

BACKGROUND: Long-term air pollution exposure has been associated with increased risk of mortality and stroke. Less is known about the risk at lower concentrations. The association of long-term exposure to PM2.5, PM2.5 absorbance, NO2, and NOx with all-cause mortality and stroke was investigated in a cohort of men aged ≥ 65 years who lived in metropolitan Perth, Western Australia. METHODS: Land use regression models were used to estimate long-term exposure to air pollutants at participant's home address (n = 11,627) over 16 years. Different metrics of exposure were assigned: baseline; year before the outcome event; and average exposure across follow-up period. The Mortality Register and Hospital Morbidity Data from the Western Australia Data Linkage System were used to ascertain mortality and stroke cases. Hazard ratios (HRs) and 95% confidence intervals were estimated using Cox proportional hazard models, adjusting for age, smoking, education, and body mass index for all-cause mortality. For fatal and hospitalized stroke, the models included variables controlled for all-cause mortality plus hypertension. RESULTS: Fifty-four percent of all-participants died, 3% suffered a fatal stroke, and 14% were hospitalized stroke cases. PM2.5 absorbance increased the risk of all-cause mortality with adjusted HR of 1.12 (1.02-1.23) for baseline and average exposures, and 1.14 (1.02-1.24) for past-year exposure. There were no associations between PM2.5 absorbance, NO2, and NOx and stroke outcomes. However, PM2.5 was associated with reduced risks of fatal stroke. CONCLUSION: Long-term exposure to PM2.5 absorbance was associated with all-cause mortality among older men exposed to low concentrations; and exposure to PM2.5 was associated with reduced risk of fatal stroke.

Vehicle refuelling, use of domestic wood heaters and the risk of childhood brain tumours: Results from an Australian case-control study.

BACKGROUND: The aetiology of childhood brain tumours (CBT) is largely unknown. Damage to germ cells after parental exposure to airborne carcinogens, such as volatile organic compounds and polycyclic aromatic hydrocarbons is one plausible pathway. This analysis aimed to investigate whether parental refuelling of vehicles or the use of domestic wood heaters in key time periods relating to the child's birth was associated with an increased risk of CBT. PROCEDURE: Cases <15 years of age were recruited through 10 paediatric oncology centres around Australia; controls were recruited through nationwide random-digit dialling, frequency matched to cases on age, sex and State of residence. Exposure to refuelling and wood heaters was ascertained through questionnaires from both parents. Odds ratios (ORs) and confidence intervals (CIs) were estimated using unconditional logistic regression, adjusting for relevant covariates. RESULTS: Data were available for 306 case and 950 control families. Paternal refuelling ≥4 times/month was associated with an increased risk of CBT (OR 1.59, 95% CI: 1.11, 2.29), and a dose-dependent trend was observed (P = 0.004). No association was seen for maternal refuelling. Use of closed, but not open, wood heaters before (OR 1.51, 95% CI: 1.05, 2.15) and after (OR 1.44, 95% CI: 1.03, 2.01) the child's birth was associated with increased risk of CBT, but dose-response relationships were weak or absent. CONCLUSIONS: Paternal refuelling of vehicles ≥4 times/month and the use of closed wood heaters before the child's birth may increase the risk of CBT. Replication in larger studies is needed. Pediatr Blood Cancer 2015;62:229-234. © 2014 Wiley Periodicals, Inc.

Pharmaceuticals in biota: The impact of wastewater treatment plant effluents on fish in Australia.

Globally, pharmaceuticals and personal care products (PPCPs) are detected in surface waters receiving wastewater, yet their presence in biota, remain largely understudied. To address this, we conducted a study that measured 46 PPCPs in spot water samples and fish caught up- and downstream from wastewater treatment plants (WWTPs) in Victoria, Australia. We sampled 15 sites located along four waterways following a 3-site design: WWTP-discharge('hotspot'), 'upstream'(∼2 km) and 'downstream'(∼2 km). Spot water and fish were also sampled at reference sites >100 km from WWTP discharge (n = 3). Additionally, spot water samples were taken from WWTP effluent outflows (n = 3). From each locality, we analysed 3-12 fish (n = 131 total). In waterways, passive samplers (POCIS; ∼28d, n = 19 PPCPs) were also deployed. Individual fish (axial muscle) and water were analysed with LC-MS-MS. We found that PPCP concentrations in environmental surface water ranged from<0.02-0.97 µg/L. In WWTP effluent, the range was <0.02-1.4 µg/L. Of the 46 PPCPs analysed, 12 were detected in spot water samples and five in fish. In water, the highest concentration detected was for antidepressant venlafaxine (3 µg/L). The most frequently detected PPCPs: venlafaxine (54.9%), metoprolol (41.2%), propranolol (29.4%), carbamazepine (29.4%), caffeine (17.6%) and sulfamethoxazole (17.6%). Out of 131 fish analysed, 35 fish had detectable levels of PPCPs in the muscle tissue. The highest muscle concentrations were: venlafaxine (150 µg/kg, redfin perch), and sertraline (100 µg/kg, eel). Bioaccumulation factors ranged from 104 to 341L/kg for venlafaxine in redfins, 21-1,260L/kg for carbamazepine in redfins and eels, and 367-3,333L/kg for sertraline in eels. Based on our human health risk calculations for venlafaxine, carbamazepine, sertraline, triclosan, and caffeine, consumption of fish does not pose a significant risk to human health. Despite this, most of the detected PPCPs in surface waters exceeded 10 ng/L trigger value, which has led to further investigations by EPA. Our study highlights the need for using multiple lines of evidence for estimating risks of PPCPs.

Trees, Climate Change, and Health: An Urban Planning, Greening and Implementation Perspective.

The In Conversation: Boundary, Spanners, Thinkers and Policy Actors Round Table Series provides a platform for researchers, policy actors, and implementation experts to elevate discussion on emerging issues, present new and upcoming research, and facilitate conversations around impacts and possible solutions. This brief report, on trees, climate change, and health, reflects a conversation between the authors of this paper, along with supporting literature. It explores the potential of green spaces and trees as a viable strategy to address climate change challenges and simultaneously improve population health, well-being, and health equity. In particular, it highlights the public health benefits of trees and green space, the challenges faced in urban areas, and opportunities for the protection, maintenance and regeneration of urban green space.

Children's exposure to metals: a community-initiated study.

In 2007, it was shown that the shipping of lead (Pb) through Esperance Port in Western Australia resulted in contamination and increased Pb concentrations in children. A clean-up strategy was implemented; however, little attention was given to other metals. In consultation with the community, a cross-sectional exposure study was designed. Thirty-nine children aged 1 to 12 years provided samples of hair, urine, drinking water, residential soil and dust. Concentrations of nickel (Ni) and Pb were low in biological and environmental samples. Hair aluminium (Al) (lower than the detection limit [DL] to 251 µg/g) and copper (Cu) (7 to 415 µg/g), as well as urinary Al (

Prenatal exposure to mixtures of persistent environmental chemicals and fetal growth outcomes in Western Australia.

BACKGROUND: Environmental chemicals have been implicated in the etiology of impaired fetal growth. However, few studies have assessed the effects of chemical mixtures or considered the possibility of non-monotonic exposure-response relationships for chemicals that act through the endocrine system. METHODS: We assessed exposure to polybrominated diphenyl ethers, organochlorine pesticides, metals, and perfluorinated alkyl substances in blood and urine samples collected approximately two weeks prior to delivery in 166 non-smoking pregnant women, and subsequent birth weight, length, and head circumference of neonates who were part of the Australian Maternal Exposures to Toxic Substances (AMETS) study. We used Bayesian structured additive regression models with spike-slab priors to estimate mixture effects, identify important exposures, and model non-linearity in exposure-response relationships. RESULTS: Mixtures of polybrominated diphenyl ethers, organochlorine pesticides, metals, and perfluorinated alkyl substances were not associated with fetal growth outcomes. Estimated change in fetal growth outcomes for an increase in exposure from the 25th to 75th percentile suggested no meaningful associations; the strongest evidence was for a small inverse association between birth weight and cesium exposure measured in whole blood (-124 g, 90% credible interval: -240 to -3 g). We identified several chemicals that may be associated with fetal growth non-linearly; however, 90% credible intervals contained small values consistent with no meaningful association. CONCLUSIONS: Using a Bayesian penalized regression method, we assessed the shapes of exposure-response relationships, controlled for confounding by co-exposure, and estimated the single and combined effects of a large mixture of correlated environmental chemicals on fetal growth. Our findings, based on a small sample of mother-neonate pairs, suggest that mixtures of persistent chemicals are not associated with birth weight, length, and head circumference. The potential for non-monotonic relationships between environmental chemicals and fetal growth outcomes warrants further study.

Exposures to lead.

The Pacific Basin Consortium for Environment and Health hosted a workshop on Exposures to Lead. Speakers from Australia and the United States of America addressed current research knowledge on lead exposures and health effects in children, risk assessment and communication issues in dealing with lead exposure sources, different methods for assessing exposure, and the variety of scenarios where lead still remains a pollutant of concern. Mining continues to be a source of lead for many communities, and approaches to reducing exposures in these settings present particular challenges. A Perth Declaration for the Global Reduction of Childhood Lead Exposure was signed by participants of the meeting and is aimed at increasing attention to the need to continue to assess lead in the environment and to develop strategies to reduce lead in the environment and exposure by communities.

Per- and Polyfluoroalkyl Substances in Ducks and the Relationship with Concentrations in Water, Sediment, and Soil.

The present study examined the occurrence and concentration of per- and polyfluoroalkyl substances (PFAS) measured in game ducks (13 compounds), water, sediment, and soils (33 compounds) in waterways in Victoria, Australia. The study aimed to identify potential ecological and human health risks from measured PFAS concentrations. Four species of duck and samples of water, sediment, and soil were collected from 19 wetlands, which were chosen based on their popularity as hunting locations. The risks posed by 3 PFAS (perfluorooctanoic acid, perfluorohexane sulfonic acid [PFHxS], and perfluorooctane sulfonic acid [PFOS]) to the environment and human health were assessed using available national ecological and human health guidelines. A diverse range of short- and long-chain carboxylic and sulfonic acids were found in the environment and in ducks. Concentrations were generally low and varied between wetlands, duck species, tissue analyzed (breast or liver), and environmental compartment (water, sediment, soil). Higher PFOS concentrations in water and sediments were observed at wetlands near sources of contamination (i.e., a defense base or urban environment). Elevated PFOS and PFOS + PFHxS concentrations in ducks were observed near local point sources but also at wetlands with no known point sources of contamination. There were clear differences in PFAS concentrations detected in duck tissues versus the environment, highlighting complexities of bioaccumulation, movement of animals, and spatiotemporal variation and raising questions about the relevance of using abiotic criteria to assess risk to biota. Human health risk assessment showed that only ducks inhabiting wetlands near local sources of PFAS were likely to pose a risk to consumers. Further studies are required to improve our knowledge of PFAS toxicokinetics and chronic impacts in biota to guide management decisions. Environ Toxicol Chem 2021;40:846-858. © 2020 SETAC.

Suggestions for Improving the Characterization of Risk from Exposures to Per and Polyfluorinated Alkyl Substances.

Many state and federal environmental and health agencies have developed risk-based criteria for assessing the risk of adverse health effects of per- and polyfluorinated alkyl substances (PFAS) exposure to humans and the environment. However, the criteria that have been developed vary; drinking water criteria developed for perfluorooctanoic acid, for example, can vary by up to 750 fold. This is due to differences and variability in the data and information used, study/endpoint selection, assumptions and magnitude of uncertainty factors used in the absence and extrapolation of critical effect data, differences in underlying approaches to addressing exposure within criteria development, and/or policy decisions on levels of acceptable risk. We have critically evaluated the methods used to develop these criteria while focusing on derivation and application of drinking water criteria and discuss a range of improvements to risk-characterization practice recently presented at a Focused Topic Meeting on PFAS conducted by the Society of Environmental Toxicology and Chemistry in Durham, North Carolina, USA, 12 to 15 August 2019. We propose methods that consider maximizing the use of disparate data streams, seeking patterns, and proposing biologically based approaches to evidence integration toward informed criteria development. Environ Toxicol Chem 2021;40:883-898. © 2020 SETAC.

Emission factors and composition of PM2.5 from laboratory combustion of five Western Australian vegetation types.

This study investigated the emission of PM10 and PM2.5 (particulates with diameters of less than 10 µm and 2.5 µm, respectively) and the chemical composition of PM2.5 from laboratory combustion of five Australian vegetation types (three grasslands, a woodland and a forest). A mix of plants representative of Banksia (woodland) and Jarrah (forest) and three types of grasses (Spinifex - Triodia basedowii; Kimberley grass - Sehima nervosum and Heteropogon contortus; and an invasive grass (Veldt) - Ehrharta calycina) were burnt in 9 combustion conditions comprised of 3 fuel moisture levels (dry, moist, wet) and 3 air flow rates (no, low and high flow). PM (particulate matter) samples were collected onto filters and measured using gravimetric analysis. PM2.5 was then extracted and analyzed for water-soluble metals and polycyclic aromatic hydrocarbons (PAH) concentrations. The largest proportion of PM10 (98%) from vegetation fires was PM2.5. Banksia yielded the highest PM2.5 emission factor (EF), followed by Jarrah and Spinifex. Veldt grass combustion generated significantly higher emissions of PM2.5 compared with the other two grass types. High moisture contents and flow rates resulted in larger emissions of PM2.5. A strong correlation (R2 = 0.84) was observed between the EF for PM2.5 and combustion efficiency, suggesting higher PM emission with lower combustion efficiencies. Potassium and sodium were the most abundant PM2.5-bound water soluble metals, accounting for more than 97% of the total mass of metals analyzed. PAHs were found in significant concentrations, including the carcinogenic benzo(a)pyrene. Pyrene and fluoranthene were the most abundant PAHs detected, accounting for nearly 40% mass of the total PAHs. Indeno(1,2,3-cd)pyrene and benzo(g,h,i)perylene ratio (IND/IND + BghiP) appeared to be produced in a diagnostic ratio that indicated that the PAHs were derived from vegetation fires rather than other sources of emissions. The EF for PM2.5 and its chemical composition (water-soluble metals and PAHs) were strongly influenced by the type of vegetation burned. The results presented in this study could be useful in predicting the risks of human health effects on firefighters and the public who may be exposed to regular bushfires in Australia.

Roof cavity dust as an exposure proxy for extreme air pollution events.

Understanding exposure to air pollution during extreme events such as fire emergencies is critical for assessing their potential health impacts. However, air pollution emergencies often affect places without a network of air quality monitoring and characterising exposure retrospectively is methodologically challenging due to the complex behaviour of smoke and other air pollutants. Here we test the potential of roof cavity (attic) dust to act as a robust household-level exposure proxy, using a major air pollution event associated with a coal mine fire in the Latrobe Valley, Australia, as an illustrative study. To assess the relationship between roof cavity dust composition and mine fire exposure, we analysed the elemental and polycyclic aromatic hydrocarbon composition of roof cavity dust (<150µm) from 39 homes along a gradient of exposure to the mine fire plume. These homes were grouped into 12 zones along this exposure gradient: eight zones across Morwell, where mine fire impacts were greatest, and four in other Latrobe Valley towns at increasing distance from the fire. We identified two elements-barium and magnesium-as 'chemical markers' that show a clear and theoretically grounded relationship with the brown coal mine fire plume exposure. This relationship is robust to the influence of plausible confounders and contrasts with other, non-mine fire related elements, which showed distinct and varied distributional patterns. We conclude that targeted components of roof cavity dust can be a useful empirical marker of household exposure to severe air pollution events and their use could support epidemiological studies by providing spatially-resolved exposure estimates post-event.

Emerging and legacy contaminants across land-use gradients and the risk to aquatic ecosystems.

Information on potentially harmful emerging and legacy chemicals is essential to understand the risks to the environment and inform regulatory actions. The objective of this study was to assess the occurrence, concentration, and distribution of emerging and legacy contaminants across a gradient of land-use intensity and determine the risk posed to aquatic ecosystems. The land-use intensity gradient considered was: background/undeveloped < low-intensity agriculture < high-intensity agriculture < urban residential < urban industrial. Twenty-five sites were sampled for surface water, sediment, and soil. A total of 218 chemicals were analyzed: pesticides, per- and poly-fluoroalkyl substances (PFAS), polybrominated biphenyls and polybrominated diphenyl ethers (PBDEs), phthalates, and short-chain chlorinated paraffins (SCCPs). The risk posed by the analyzed chemicals to the aquatic environment was measured using hazard quotients (HQs), which were calculated by dividing the maximum measured environmental concentration by a predicted no-effect concentration for each chemical. A HQ > 1 was considered to indicate a high risk of adverse effects from the given chemical. A total of 68 chemicals were detected: 19 pesticides, 18 PFAS, 28 PBDEs, two phthalates, and SCCPs (as total SCCPs). There were no significant differences in the overall chemical composition between land uses. However, the insecticide bifenthrin, PFAS, PBDEs, and phthalates were more frequently found in samples from residential and/or industrial sites, suggesting urban land uses are hotspots and potential large-scale sources of these chemicals. Nineteen chemicals had a HQ > 1; most had a restricted spatial distribution limited to high-intensity agriculture and industrial sites in Melbourne. Bifenthrin and the perfluorooctanesulfonic acid (PFOS) had the highest HQs in residential and industrial sites, suggesting an increased risk to aquatic ecosystems in urban settings. The results of this study will enhance future research, predictive methods, and effective targeting of monitoring, and will help guide regulatory management actions and mitigation solutions.

Assessing urinary levoglucosan and methoxyphenols as biomarkers for use in woodsmoke exposure studies.

A major contributor to particle concentrations in urban airsheds is domestic woodsmoke and smoke arising from wildfires or management burns. Particle concentrations in urban airsheds have been associated with a wide range of health effects. There has been little research into the contribution of biomass burning to studies of human health due to the complexity of attributing effects in the presence of multiple sources of pollutants and the variability in the nature and conditions of biomass burning. A significant advance is the use of biomarkers of exposure; methoxyphenol and levoglucosan; specific compounds produced following the combustion of lignins and detected in urine. Levoglucosan has not previously been assessed for its usefulness as a marker of human exposure. We report for the first time levoglucosan concentrations in urine. Twelve participants were recruited and asked to provide spot urine samples pre- and post-exposure to a fire training exercise. Both levoglucosan and methoxyphenol were detected in the urine of participants. There was no significant increase in these compounds post-exposure to smoke arising from the fire training. Further work is required to assess this biomarker for human exposure studies and in particular the role of diet and previous exposure.

The pro-inflammatory effects of particulate matter on epithelial cells are associated with elemental composition.

BACKGROUND: Adverse health effects of particulate matter (PM) vary with chemical composition; however, evidence regarding which elements are the most detrimental is limited. The roof space area provides an open and stable environment for outdoor PM to settle and deposit. Therefore, this study used roof space PM samples as a proxy of residential cumulative exposure to outdoor air pollution to investigate their pro-inflammatory effects on human lung cells and the contribution of the endotoxin and chemical content. METHODS: Roof space PM samples of 36 different homes were collected and analysed using standardised techniques. We evaluated cytotoxicity and cytokine production of BEAS-2B cells after PM exposure using MTS and ELISA, respectively. Principle component analysis (PCA) and linear regression analyses were employed to assess the associations between cytokine production and the PM components. RESULTS: PM caused significant time- and dose-dependent increases in cellular cytokine production (p < 0.05). PCA identified four factors that explained 68.33% of the variance in the chemical composition. An increase in Factor 1 (+Fe, +Al, +Mn) score and a decrease in Factor 2 (-Ca, +Pb, +PAH) score were associated with increased interleukin (IL)-6 (Factor 1; p = 0.010; Factor 2; p = 0.006) and IL-8 (Factor 1; p = 0.003; Factor 2; p = 0.020) production, however, only the association with Factor 1 was evident after correcting for endotoxin and particle size. CONCLUSIONS: Our study provides novel insight into the positive associations between pro-inflammatory effects of roof space PM samples with Fe, Al and Mn levels.

Low-level cadmium exposure and cardiovascular outcomes in elderly Australian women: A cohort study.

BACKGROUND: Cadmium has been associated with increased risk of cardiovascular disease (CVD) in observational studies, however there has been a limited focus on this relationship in women. OBJECTIVES: This study investigated the association of urinary cadmium (UCd) concentrations with CVD outcomes and all-cause mortality in elderly Western Australian (WA) women. METHODS: UCd excretion was measured at baseline in 1359 women, mean age 75.2 ±â€¯2.7 years and 14.5 years of atherosclerotic vascular disease (ASVD) hospitalisations and deaths, including both the principle cause of death and all associated causes of death. Health outcome data were retrieved from the Western Australian Data Linkage System. Cox regression analysis was used to estimate hazard ratios of ASVD and all-cause mortality. UCd was ln-transformed and models were adjusted for demographic and CVD risk factors. RESULTS: Median (IQR) concentration of UCd was 0.18 (0.09-0.32) µg/L. In multivariable-adjusted analyses per ln unit (equivalent to ∼2.7 fold) increase in UCd, there was a 36% increase in the risk of death from heart failure and 17% increase in the risk of a heart failure event, respectively (HR = 1.36, 95% CI 1.11-1.67; HR = 1.17, 95% CI 1.01-1.35). When analyses were restricted to never smokers the relationship between UCd and death from heart failure remained (HR 1.29, 95% CI 1.01-1.63). CONCLUSIONS: This study suggests that even at low levels of exposure cadmium may be associated with heart failure hospitalisations and deaths in older women, however given the dilute nature of these urine samples, the results must be interpreted with caution.

Risk factors for increased BTEX exposure in four Australian cities.

Benzene, toluene, ethylbenzene and xylenes (BTEX) are common volatile organic compounds (VOCs) found in urban airsheds. Elevated levels of VOCs have been reported in many airsheds at many locations, particularly those associated with industrial activity, wood heater use and heavy traffic. Exposure to some VOCs has been associated with health risks. There have been limited investigations into community exposures to BTEX using personal monitoring to elucidate the concentrations to which members of the community may be exposed and the main contributors to that exposure. In this cross sectional study we investigated BTEX exposure of 204 non-smoking, non-occupationally exposed people from four Australian cities. Each participant wore a passive BTEX sampler over 24h on five consecutive days in both winter and summer and completed an exposure source questionnaire for each season and a diary for each day of monitoring. The geometric mean (GM) and range of daily BTEX concentrations recorded for the study population were benzene 0.80 (0.04-23.8 ppb); toluene 2.83 (0.03-2120 ppb); ethylbenzene 0.49 (0.03-119 ppb); and xylenes 2.36 (0.04-697 ppb). A generalised linear model was used to investigate significant risk factors for increased BTEX exposure. Activities and locations found to increase personal exposure included vehicle repair and machinery use, refuelling of motor vehicles, being in an enclosed car park and time spent undertaking arts and crafts. A highly significant difference was found between the mean exposures in each of the four cities, which may be explained by differences in fuel composition, differences in the mix and density of industry, density of motor vehicles and air pollution meteorology.

In vitro assessment of the toxicity of bushfire emissions: A review.

Bushfires produce many toxic pollutants and the smoke has been shown to have negative effects on human health, especially to the respiratory system. Bushfires are predicted to increase in size and frequency, leading to a greater incidence of smoke and impacts. While there are many epidemiological studies of the potential impact on populations, there are few studies using in vitro methods to investigate the biological effects of bushfire emissions to better understand its toxicity and significance. This review focused on the literature pertaining to in vitro toxicity testing to determine the state of knowledge on current methods and findings on the impacts of bushfire smoke. There was a considerable variation in the experimental conditions, outcomes and test concentrations used by researchers using in vitro methods. Of the studies reviewed, most reported adverse impacts of particulate matter (PM) on cytotoxic and genotoxic responses. Studies on whole smoke were rare. Finer primary particulates from bushfire smoke were generally found to be more toxic than the coarse particulates and the toxicological endpoints of bushfire PM different to ambient PM. However the variation in study designs and experimental conditions made comparisons difficult. This review highlights the need for standard protocols to enable appropriate comparisons between studies to be undertaken including the assessment of physiologically relevant outcomes. Further work is essential to establish the effect of burning different vegetation types and combustion conditions on the toxicity of bushfire emissions to better inform both health and response agencies on the significance of smoke from bushfires.

Relationship between antibiotic resistance genes and metals in residential soil samples from Western Australia.

Increasing drug-resistant infections have drawn research interest towards examining environmental bacteria and the discovery that many factors, including elevated metal conditions, contribute to proliferation of antibiotic resistance (AR). This study examined 90 garden soils from Western Australia to evaluate predictions of antibiotic resistance genes from total metal conditions by comparing the concentrations of 12 metals and 13 genes related to tetracycline, beta-lactam and sulphonamide resistance. Relationships existed between metals and genes, but trends varied. All metals, except Se and Co, were related to at least one AR gene in terms of absolute gene numbers, but only Al, Mn and Pb were associated with a higher percentage of soil bacteria exhibiting resistance, which is a possible indicator of population selection. Correlations improved when multiple factors were considered simultaneously in a multiple linear regression model, suggesting the possibility of additive effects occurring. Soil-metal concentrations must be considered when determining risks of AR in the environment and the proliferation of resistance.

Investigating the relationship between environmental factors and respiratory health outcomes in school children using the forced oscillation technique.

The environmental factors which may affect children's respiratory health are complex, and the influence and significance of factors such as traffic, industry and presence of vegetation is still being determined. We undertook a cross-sectional study of 360 school children aged 5-12 years who lived on the outskirts of a heavy industrial area in Western Australia to investigate the effect of a range of environmental factors on respiratory health using the forced oscillation technique (FOT), a non-invasive method that allows for the assessment of the resistive and reactive properties of the respiratory system. Based on home address, proximity calculations were used to estimate children's exposure to air pollution from traffic and industry and to characterise surrounding green space. Indoor factors were determined using a housing questionnaire. Of the outdoor measures, the length of major roads within a 50m buffer was associated with increased airway resistance (Rrs8). There were no associations between distance to industry and FOT measures. For the indoor environment the presence of wood heating and gas heating in the first year of life was associated with better lung function. The significance of both indoor and outdoor sources of air pollution and effect modifiers such as green space and heating require further investigation.

Acid sulphate soil disturbance and metals in groundwater: implications for human exposure through home grown produce.

A significant emerging environmental problem is the disturbance and oxidation of soils with high levels of iron sulphide minerals resulting in acidification and causing the mobilization of metals into groundwater. This process is occurring in many parts of the world. In Western Australia, impacted groundwater is extracted by residents for domestic use. We sought to establish domestic use patterns of bore water and the concentration of metals. Sixty-seven domestic bore water samples clearly indicated oxidation of sulphidic materials with heavy metal concentrations ranging for aluminium (