Socioeconomic status and public health in Australia: A wastewater-based study.

Analysis of untreated municipal wastewater is recognized as an innovative approach to assess population exposure to or consumption of various substances. Currently, there are no published wastewater-based studies investigating the relationships between catchment social, demographic, and economic characteristics with chemicals using advanced non-targeted techniques. In this study, fifteen wastewater samples covering 27% of the Australian population were collected during a population Census. The samples were analysed with a workflow employing liquid chromatography high-resolution mass spectrometry and chemometric tools for non-target analysis. Socioeconomic characteristics of catchment areas were generated using Geospatial Information Systems software. Potential correlations were explored between pseudo-mass loads of the identified compounds and socioeconomic and demographic descriptors of the wastewater catchments derived from Census data. Markers of public health (e.g., cardiac arrhythmia, cardiovascular disease, anxiety disorder and type 2 diabetes) were identified in the wastewater samples by the proposed workflow. They were positively correlated with descriptors of disadvantage in education, occupation, marital status and income, and negatively correlated with descriptors of advantage in education and occupation. In addition, markers of polypropylene glycol (PPG) and polyethylene glycol (PEG) related compounds were positively correlated with housing and occupation disadvantage. High positive correlations were found between separated and divorced people and specific drugs used to treat cardiac arrhythmia, cardiovascular disease, and depression. Our robust non-targeted methodology in combination with Census data can identify relationships between biomarkers of public health, human behaviour and lifestyle and socio-demographics of whole populations. Furthermore, it can identify specific areas and socioeconomic groups that may need more assistance than others for public health issues. This approach complements important public health information and enables large-scale national coverage with a relatively small number of samples.

A novel method for the quantification of tire and polymer-modified bitumen particles in environmental samples by pyrolysis gas chromatography mass spectroscopy.

Tire and road wear particles may constitute the largest source of microplastic particles into the environment. Quantification of these particles are associated with large uncertainties which are in part due to inadequate analytical methods. New methodology is presented in this work to improve the analysis of tire and road wear particles using pyrolysis gas chromatography mass spectrometry. Pyrolysis gas chromatography mass spectrometry of styrene butadiene styrene, a component of polymer-modified bitumen used on road asphalt, produces pyrolysis products identical to those of styrene butadiene rubber and butadiene rubber, which are used in tires. The proposed method uses multiple marker compounds to measure the combined mass of these rubbers in samples and includes an improved step of calculating the amount of tire and road based on the measured rubber content and site-specific traffic data. The method provides good recoveries of 83-92% for a simple matrix (tire) and 88-104% for a complex matrix (road sediment). The validated method was applied to urban snow, road-side soil and gully-pot sediment samples. Concentrations of tire particles in these samples ranged from 0.1 to 17.7 mg/mL (snow) to 0.6-68.3 mg/g (soil/sediment). The concentration of polymer-modified bitumen ranged from 0.03 to 0.42 mg/mL (snow) to 1.3-18.1 mg/g (soil/sediment).

Plastics contamination of store-bought rice.

This study investigated mass concentrations of selected plastics in store-bought rice, the staple of more than half the world's population. Polyethylene, polyethylene terephthalate, poly-(methyl methacrylate), polypropylene, polystyrene and polyvinyl chloride were quantified using pressurized liquid extraction coupled to double-shot pyrolysis gas chromatography/mass spectrometry. Polyethylene, polypropylene and polyethylene terephthalate were quantifiable in the rice samples with polyethylene the most frequently detected (95%). There was no statistical difference between total plastic concentration in paper and plastic packaged rice. Shaking the rice in its packaging had no significant difference on the concentration of plastics. Washing the rice with water significantly reduced plastic contamination. Instant (pre-cooked) rice contained fourfold higher levels of plastics, suggesting that industrial processing potentially increases contamination. A preliminary estimate of the intake of plastic through rice consumption for Australians established 3.7 mg per serve (100 g) if not washed and 2.8 mg if washed. Annual consumption was estimated around 1 g/person.

Quantitative Analysis of Selected Plastics in High-Commercial-Value Australian Seafood by Pyrolysis Gas Chromatography Mass Spectrometry.

Microplastic contamination of the marine environment is widespread, but the extent to which the marine food web is contaminated is not yet known. The aims of this study were to go beyond visual identification techniques and develop and apply a simple seafood sample cleanup, extraction, and quantitative analysis method using pyrolysis gas chromatography mass spectrometry to improve the detection of plastic contamination. This method allows the identification and quantification of polystyrene, polyethylene, polyvinyl chloride, polypropylene, and poly(methyl methacrylate) in the edible portion of five different seafood organisms: oysters, prawns, squid, crabs, and sardines. Polyvinyl chloride was detected in all samples and polyethylene at the highest total concentration of between 0.04 and 2.4 mg g-1 of tissue. Sardines contained the highest total plastic mass concentration (0.3 mg g-1 tissue) and squid the lowest (0.04 mg g-1 tissue). Our findings show that the total concentration of plastics is highly variable among species and that microplastic concentration differs between organisms of the same species. The sources of microplastic exposure, such as packaging and handling with consequent transference and adherence to the tissues, are discussed. This method is a major development in the standardization of plastic quantification techniques used in seafood.

Identification and quantification of selected plastics in biosolids by pressurized liquid extraction combined with double-shot pyrolysis gas chromatography-mass spectrometry.

The identification and quantification of selected plastics (polystyrene (PS), polycarbonate (PC), poly-(methyl methacrylate) (PMMA), polypropylene (PP), polyethylene terephthalate (PET), polyethylene (PE) and polyvinyl chloride (PVC)) in biosolids (treated sewage sludge) was performed by pressurized liquid extraction (PLE) combined with double-shot pyrolysis gas chromatography-mass spectrometry. Validation of the method yielded recoveries of between 85 and 128% (mean RSD 11%) at a linear range of between 0.01 and 2 µg. The distribution of plastics within 25 biosolid samples from a single wastewater treatment plant in Australia was assessed. The mass concentration of PE, PVC, PP, PS and PMMA was between 0.1 and 4.1 mg/g dry weight (dw) across all samples, with a total plastic concentration Æ©Plastics of between 2.8 and 6.6 mg/g dw (median = 4.1 mg/g dw). PE was the predominant plastic detected (mean concentration of 2.2 mg/g dw), contributing to 50% of the total of all plastics. Overall, this study demonstrates that pressurized liquid extraction (PLE) combined with double-shot pyrolysis gas chromatography-mass spectrometry can be used to identify and quantify PE, PP, PVC, PS, and PMMA in biosolids.

A two stage algorithm for target and suspect analysis of produced water via gas chromatography coupled with high resolution time of flight mass spectrometry.

Gas chromatography coupled with high resolution time of flight mass spectrometry (GC-HR-TOFMS) has gained popularity for the target and suspect analysis of complex samples. However, confident detection of target/suspect analytes in complex samples, such as produced water, remains a challenging task. Here we report on the development and validation of a two stage algorithm for the confident target and suspect analysis of produced water extracts. We performed both target and suspect analysis for 48 standards, which were a mixture of 28 aliphatic hydrocarbons and 20 alkylated phenols, in 3 produced water extracts. The two stage algorithm produces a chemical standard database of spectra, in the first stage, which is used for target and suspect analysis during the second stage. The first stage is carried out through five steps via an algorithm here referred to as unique ion extractor (UIE). During the first step the m/z values in the spectrum of a standard that do not belong to that standard are removed in order to produce a clean spectrum and then during the last step the cleaned spectrum is calibrated. The Dot-product algorithm, during the second stage, uses the cleaned and calibrated spectra of the standards for both target and suspect analysis. We performed the target analysis of 48 standards in all 3 samples via conventional methods, in order to validate the two stage algorithm. The two stage algorithm was demonstrated to be more robust, reliable, and less sensitive to the signal-to-noise ratio (S/N), when compared to the conventional method. The Dot-product algorithm showed lower potential in producing false positives compared to the conventional methods, when dealing with complex samples. We also evaluated the effect of the mass accuracy on the performances of Dot-product algorithm. Our results indicated the crucial importance of HR-MS data and the mass accuracy for confident suspect analysis in complex samples.

Analyte quantification with comprehensive two-dimensional gas chromatography: assessment of methods for baseline correction, peak delineation, and matrix effect elimination for real samples.

Comprehensive two-dimensional gas chromatography (GC×GC) is used widely to separate and measure organic chemicals in complex mixtures. However, approaches to quantify analytes in real, complex samples have not been critically assessed. We quantified 7 PAHs in a certified diesel fuel using GC×GC coupled to flame ionization detector (FID), and we quantified 11 target chlorinated hydrocarbons in a lake water extract using GC×GC with electron capture detector (µECD), further confirmed qualitatively by GC×GC with electron capture negative chemical ionization time-of-flight mass spectrometer (ENCI-TOFMS). Target analyte peak volumes were determined using several existing baseline correction algorithms and peak delineation algorithms. Analyte quantifications were conducted using external standards and also using standard additions, enabling us to diagnose matrix effects. We then applied several chemometric tests to these data. We find that the choice of baseline correction algorithm and peak delineation algorithm strongly influence the reproducibility of analyte signal, error of the calibration offset, proportionality of integrated signal response, and accuracy of quantifications. Additionally, the choice of baseline correction and the peak delineation algorithm are essential for correctly discriminating analyte signal from unresolved complex mixture signal, and this is the chief consideration for controlling matrix effects during quantification. The diagnostic approaches presented here provide guidance for analyte quantification using GC×GC.