Jake O'Brien

Wastewater analysis of Census day samples to investigate per capita input of organophosphorus flame retardants and plasticizers into wastewater

The use of organophosphate esters (PFRs) as flame retardants and plasticizers has increased due to the ban of some brominated flame retardants. There is however some concern regarding the toxicity, particularly carcinogenicity and neurotoxicity, of some of the PFRs. In this study we applied wastewater analysis to assess use of PFRs by the Australian population. Influent samples were collected from eleven wastewater treatment plants (STPs) in Australia on Census day and analysed for PFRs using gas chromatography coupled with mass spectrometry (GC-MS). Per capita mass loads of PFRs were calculated using the accurate Census head counts. The results indicate that tris(2-butoxyethyl) phosphate (TBOEP) has the highest per capita input into wastewater followed by tris(2-chloroisopropyl) phosphate (TCIPP), tris(isobutyl) phosphate (TIBP), tris(2-chloroethyl) phosphate (TCEP) and tris(1,3-dichloroisopropyl) phosphate (TDCIPP). Similar PFR profiles were observed across the Australian STPs and a comparison with European and U.S. STPs indicated similar PFR concentrations. We estimate that approximately 2.1 mg person(-1) day(-1) of PFRs are input into Australian wastewater which equates to 16 tonnes per annum.

Measuring biomarkers in wastewater as a new source of epidemiological information: Current state and future perspectives

The information obtained from the chemical analysis of specific human excretion products (biomarkers) in urban wastewater can be used to estimate the exposure or consumption of the population under investigation to a defined substance. A proper biomarker can provide relevant information about lifestyle habits, health and wellbeing, but its selection is not an easy task as it should fulfil several specific requirements in order to be successfully employed. This paper aims to summarize the current knowledge related to the most relevant biomarkers used so far. In addition, some potential wastewater biomarkers that could be used for future applications were evaluated. For this purpose, representative chemical classes have been chosen and grouped in four main categories: (i) those that provide estimates of lifestyle factors and substance use, (ii) those used to estimate the exposure to toxicants present in the environment and food, (iii) those that have the potential to provide information about public health and illness and (iv) those used to estimate the population size. To facilitate the evaluation of the eligibility of a compound as a biomarker, information, when available, on stability in urine and wastewater and pharmacokinetic data (i.e. metabolism and urinary excretion profile) has been reviewed. Finally, several needs and recommendations for future research are proposed.

Spatial variations in the consumption of illicit stimulant drugs across Australia: A nationwide application of wastewater-based epidemiology

Obtaining representative information on illicit drug use and patterns across a country remains difficult using surveys because of low response rates and response biases. A range of studies have used wastewater-based epidemiology (WBE) as a complementary approach to monitor community-wide illicit drug use. In Australia, no large-scale WBE studies have been conducted to date to reveal illicit drug use profiles in a national context. In this study, we performed the first Australia-wide WBE monitoring to examine spatial patterns in the use of three illicit stimulants (cocaine, as its human metabolite benzoylecgonine; methamphetamine; and 3,4-methylendioxymethamphetamine (MDMA)). A total of 112 daily composite wastewater samples were collected from 14 wastewater treatment plants across four states and two territories. These covered approximately 40% of the Australian population. We identified and quantified illicit drug residues using liquid chromatography coupled with tandem mass spectrometry. There were distinctive spatial patterns of illicit stimulant use in Australia. Multivariate analyses showed that consumption of cocaine and MDMA was higher in the large cities than in rural areas. Also, cocaine consumption differed significantly between different jurisdictions. Methamphetamine consumption was more similar between urban and rural locations. Only a few cities had elevated levels of use. Extrapolation of the WBE estimates suggested that the annual consumption was 3tonnes for cocaine and 9tonnes combined for methamphetamine and MDMA, which outweighed the annual seizure amount by 25 times and 45 times, respectively. These ratios imply the difficulty of detecting the trafficking of these stimulants in Australia, possibly more so for methamphetamine than cocaine. The obtained spatial pattern of use was compared with that in the most recent national household survey. Together both WBE and survey methods provide a more comprehensive evaluation of drug use that can assist governments in developing policies to reduce drug use and harm in the communities.

Measuring selected PPCPs in wastewater to estimate the population in different cities in China.

Sampling and analysis of wastewater from municipal wastewater treatment plants (WWTPs) has become a useful tool for understanding exposure to chemicals. Both wastewater based studies and management and planning of the catchment require information on catchment population in the time of monitoring. Recently, a model has been developed and calibrated using selected pharmaceutical and personal care products (PPCPs) measured in influent wastewater for estimating population in different catchments in Australia. The present study aimed at evaluating the feasibility of utilizing this population estimation approach in China. Twenty-four hour composite influent samples were collected from 31 WWTPs in 17 cities with catchment sizes from 200,000-3,450,000 people representing all seven regions of China. The samples were analyzed for 19 PPCPs using liquid chromatography coupled to tandem mass spectrometry in direct injection mode. Eight chemicals were detected in more than 50% of the samples. Significant positive correlations were found between individual PPCP mass loads and population estimates provided by WWTP operators. Using the PPCP mass load modeling approach calibrated with WWTP operator data, we estimated the population size of each catchment with good agreement with WWTP operator values (between 50-200% for all sites and 75-125% for 23 of the 31 sites). Overall, despite much lower detection and relatively high heterogeneity in PPCP consumption across China the model provided a good estimate of the population contributing to a given wastewater sample. Wastewater analysis could also provide objective PPCP consumption status in China.

Trends in methamphetamine residues in wastewater in metropolitan and regional cities in south-east Queensland, 2009-2015

Over the past several years, the Australian media have reported increased use and harm arising from the use of crystal methamphetamine (“ice”),1,2 a highly pure form of the drug that can be smoked or injected.2 We used wastewater analysis to examine trends in methamphetamine residues in wastewater samples from the inlets of two treatment plants in south-east Queensland. One plant served a coastal metropolitan city that included entertainment precincts and the other a major inland regional city...

Refining the excretion factors of methadone and codeine for wastewater analysis — Combining data from pharmacokinetic and wastewater studies

Analysing drug residues in wastewater (wastewater analysis) to monitor the consumption of those drugs in the population has become a complementary method to epidemiological surveys. In this method, the excretion factor of a drug (or the percentage of drug metabolites excreted through urine) is a critical parameter for the back-estimation of the consumption of a drug. However, this parameter is usually derived from a small database of human pharmacokinetic studies. This is true for methadone and codeine, the two most commonly used opioids and also common substances of abuse. Therefore, we aimed to refine the current excretion factors used for estimating methadone and codeine by analysing published data from the literature on the excretion of methadone, its main metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), and codeine. Our review included both human drug pharmacokinetic studies and wastewater analysis studies. We found that while the commonly used excretion factor of methadone (~27.5%) was relatively accurate, the excretion factor of EDDP, a better biomarker for methadone consumption in sewer epidemiology, should be twice that of methadone (i.e. 55%) instead of the current equal or half values. For codeine, the excretion factor should be ~30% instead of 63.5% or 10% as previously used in wastewater analysis studies. Data from wastewater analysis studies could be used in this way to refine the excretion factors of the drugs of interest.

Cocaine, MDMA and methamphetamine residues in wastewater: consumption trends (2009-2015) in South East Queensland, Australia

Wastewater analysis, or wastewater-based epidemiology, has become a common tool to monitor trends of illicit drug consumption around the world. In this study, we examined trends in cocaine, 3,4-methylenedioxymethamphetamine (MDMA) and methamphetamine consumption by measuring their residues in wastewater from two wastewater treatment plants in Australia (specifically, an urban and a rural catchment, both in South East Queensland) between 2009 and 2015. With direct injection of the samples, target analytes were identified and quantified using liquid chromatography-mass spectrometry. Cocaine and MDMA residues and metabolites were mainly quantifiable in the urban catchment while methamphetamine residues were consistently detected in both urban and rural catchments. There was no consistent trend in the population normalised mass loads observed for cocaine and MDMA at the urban site between 2009 and 2015. In contrast, there was a five-fold increase in methamphetamine consumption over this period in this catchment. For methamphetamine consumption, the rural area showed a very similar trend as the urban catchment starting at a lower baseline. The observed increase in per capita loads of methamphetamine via wastewater analysis over the past six years in South East Queensland provides objective evidence for increased methamphetamine consumption in the Australian population while the use of other illicit stimulants remained relatively stable.

A Miniature Bioassay for Testing the Acute Phytotoxicity of Photosystem II Herbicides on Seagrass

Photosystem II (PSII) herbicides have been detected in nearshore tropical waters such as those of the Great Barrier Reef and may add to the pressure posed by runoff containing sediments and nutrients to threatened seagrass habitats. There is a growing number of studies into the potential effects of herbicides on seagrass, generally using large experimental setups with potted plants. Here we describe the successful development of an acute 12-well plate phytotoxicity assay for the PSII herbicide Diuron using isolated Halophila ovalis leaves. Fluorescence images demonstrated Diuron affected the entire leaf surface evenly and responses were not influenced by isolating leaves from the plant. The optimum exposure duration was 24 h, by which time the inhibition of effective quantum yield of PSII (∆F/Fm’) was highest and no deterioration of photosystems was evident in control leaves. The inhibition of ∆F/Fm’ by Diuron in isolated H. ovalis leaves was identical to both potted and hydroponically grown plants (with leaves remaining attached to rhizomes), indicating similar reductions in photosynthetic activity in these acute well-plate assays. The sensitivity of the assay was not influenced by irradiance (range tested 40 to 400 μmol photons m-2 s-1). High irradiance, however, caused photo-oxidative stress in H. ovalis and this generally impacted in an additive or sub-additive way with Diuron to damage PSII. The bioassay using isolated leaves is more rapid, uses far less biological material and does not rely on specialised aquarium facilities in comparison with assays using potted plants. The development and validation of this sensitive bioassay will be useful to reliably screen and monitor the phytotoxicity of existing and emerging PSII herbicides and contribute to risk assessments and water quality guideline development in the future.

Medium-Chain Chlorinated Paraffins (CPs) Dominate in Australian Sewage Sludge

To simultaneously quantify and profile the complex mixture of short-, median-, and long-chain CPs (SCCPs, MCCPs, and LCCPs) in Australian sewage sludge, we applied and further validated a recently developed novel instrumental technique, using quadrupole time-of-flight high resolution mass spectrometry running in the negative atmospheric pressure chemical ionization mode (APCI-qTOF-HRMS). Without using an analytical column the cleaned extracts were directly injected into the qTOF-HRMS followed by quantification of the CPs by a mathematical algorithm. The recoveries of the four SCCP, MCCP and LCCP-spiked sewage sludge samples ranged from 86 to 123%. This APCI-qTOF-HRMS method is a fast and promising technique for routinely measuring SCCPs, MCCPs, and LCCPs in sewage sludge. Australian sewage sludge was dominated by MCCPs with concentrations ranging from 542 to 3645 ng/g dry weight (dw). Lower SCCPs concentrations (<57–1421 ng/g dw) were detected in the Australian sewage sludge, which were comparable with the LCCPs concentrations (116–960 ng/g dw). This is the first time that CPs were reported in Australian sewage sludge. The results of this study gives a first impression on the distribution of the SCCPs, MCCPs, and LCCPs in Australia wastewater treatment plants (WWTPs).

Degradation of herbicides in the tropical marine environment: influence of light and sediment

Widespread contamination of nearshore marine systems, including the Great Barrier Reef (GBR) lagoon, with agricultural herbicides has long been recognised. The fate of these contaminants in the marine environment is poorly understood but the detection of photosystem II (PSII) herbicides in the GBR year-round suggests very slow degradation rates. Here, we evaluated the persistence of a range of commonly detected herbicides in marine water under field-relevant concentrations and conditions. Twelve-month degradation experiments were conducted in large open tanks, under different light scenarios and in the presence and absence of natural sediments. All PSII herbicides were persistent under control conditions (dark, no sediments) with half-lives of 300 d for atrazine, 499 d diuron, 1994 d hexazinone, 1766 d tebuthiuron, while the non-PSII herbicides were less persistent at 147 d for metolachlor and 59 d for 2,4-D. The degradation of herbicides was 2–10 fold more rapid in the presence of a diurnal light cycle and coastal sediments; apart from 2,4-D which degraded more slowly in the presence of light. Despite the more rapid degradation observed for most herbicides in the presence of light and sediments, the half-lives remained > 100 d for the PS II herbicides. The effects of light and sediments on herbicide persistence were likely due to their influence on microbial community composition and its ability to utilise the herbicides as a carbon source. These results help explain the year-round presence of PSII herbicides in marine systems, including the GBR, but more research on the transport, degradation and toxicity on a wider range of pesticides and their transformation products is needed to improve their regulation in sensitive environments.