49 research outputs found
Converting mg/L to Particles/L: Reconciling the Occurrence and Toxicity Literature on Microplastics
No full textMicroplastics (MPs) and nanoplastics are small plastic particles (1–5000 μm and 1–1000 nm, respectively) that are ubiquitous contaminants in our environment. Their extreme persistence makes them a particularly problematic contaminant of emerging concern (CEC). Studies over the past decade have reported MPs in all environmental compartments: air, water, soil, sediment, and biota. Due to the way these microscopic particles are extracted and analyzed, concentrations of MPs in the environment are almost exclusively reported as number of particles in a specific volume, such as particles/L, particles/m3, particles/g, etc. Concentrations as high as 102 000 particles/m3 in coastal waters, 175 particles/m3 in air, 42 960 particles/kg in soils, 4650 particles/m3 in freshwater, and 9597 particles/kg in freshwater sediment have been reported (reviewed in (1and2)). In parallel, a growing number of (eco)toxicity studies have focused on the adverse impacts from exposure of a wide range of biota to MPs, ranging from sublethal effects (e.g., oxidative stress, inflammation, diminished growth, reduced reproduction) to acute toxicity. Toxicity studies generally report effect concentrations in units of mass per volume, such as mg/L, because MPs are weighed and mixed in test water for accurate dosing. Most adverse effects to date have been reported in the mg/L or μg/L range for micro- and nanoplastics, respectively. For example, half of the exposed Daphnia magna subjects were immobilized after 48h of exposure to 66.97 mg/L or 660 μg/L of 1 or 0.11 μm polystyrene (PS) beads, respectively (reviewed in (3)). The difference in units (particles/L in the occurrence literature vs. mg/L in the toxicity literature) has made it particularly difficult to compare the two sets of data and properly assess the risk of MPs because of the uncertainty about how to convert from one to the other.No Full Tex
Wastewater treatment plants as a pathway for microplastics: Development of a new approach to sample wastewater-based microplastics
No full textWastewater effluent is expected to be a pathway for microplastics to enter the aquatic environment, with microbeads from cosmetic products and polymer fibres from clothes likely to enter wastewater treatment plants (WWTP). To date, few studies have quantified microplastics in wastewater. Moreover, the lack of a standardized and applicable method to identify microplastics in complex samples, such as wastewater, has limited the accurate assessment of microplastics and may lead to an incorrect estimation. This study aimed to develop a validated method to sample and process microplastics from wastewater effluent and to apply the developed method to quantify and characterise wastewater-based microplastics in effluent from three WWTPs that use primary, secondary and tertiary treatment processes. We applied a high-volume sampling device that fractionated microplastics in situ and an efficient sample processing procedure to improve the sampling of microplastics in wastewater and to minimize the false detection of non-plastic particles. The sampling device captured between 92% and 99% of polystyrene microplastics using 25 μm–500 μm mesh screens in laboratory tests. Microplastic type, size and suspected origin in all studied WWTPs, along with the removal efficiency during the secondary and tertiary treatment stages, was investigated. Suspected microplastics were characterised using Fourier Transform Infrared spectroscopy, with between 22 and 90% of the suspected microplastics found to be non-plastic particles. An average of 0.28, 0.48 and 1.54 microplastics per litre of final effluent was found in tertiary, secondary and primary treated effluent, respectively. This study suggests that although low concentrations of microplastics are detected in wastewater effluent, WWTPs still have the potential to act as a pathway to release microplastics given the large volumes of effluent discharged to the aquatic environment. This study focused on a single sampling campaign, with long-term monitoring recommended to further characterise microplastics in wastewater.Griffith Sciences, Griffith School of EnvironmentNo Full Tex
Assessing granular media filtration for the removal of chemical contaminants from wastewater
No full textGranular media filtration was evaluated for the removal of a suite of chemical contaminants that can be found in wastewater. Laboratory- and pilot-scale sand and granular activated carbon (GAC) filters were trialled for their ability to remove atrazine, estrone (E1), 17α-ethynylestradiol (EE2), N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMOR) and N-nitrosodiethylamine (NDEA). In general, sand filtration was ineffective in removing the contaminants from a tertiary treated wastewater, with the exception of E1 and EE2, where efficient removals were observed after approximately 150 d. Batch degradation experiments confirmed that the removal of E1 was through biological activity, with a pseudo-first-order degradation rate constant of 7.4 × 10−3 h−1. GAC filtration was initially able to effectively remove all contaminants; although removals decreased over time due to competition with other organics present in the water. The only exception was atrazine where removal remained consistently high throughout the experiment. Previously unreported differences were observed in the adsorption of the three nitrosamines, with the ease of removal following the trend, NDEA > NMOR > NDMA, consistent with their hydrophobic character. In most instances the removals from the pilot-scale filters were generally in agreement with the laboratory-scale filter, suggesting that there is potential in using laboratory-scale filters as monitoring tools to evaluate the performance of pilot- and possibly full-scale sand and GAC filters at wastewater treatment plants.Lionel Ho, Charlotte Grasset, Daniel Hoefel, Mike B. Dixon, Frederic D. L. Leusch, Gayle Newcombe, Christopher P. Saint and Justin D. Brooke
Anaerobic digestion of sewage sludge has no effect on glucocorticoid and anti-progestagenic activity but increases estrogenicity three-fold
No full textAlthough the recovery and beneficial reuse of organic matter and nutrients from sludge represents an important move towards environmental sustainability, the accumulation of chemicals in biosolid-amended soils could pose serious environmental and human health risks. However, (eco)toxicological profiling of complex chemical mixtures in biosolids is currently limited. In particular, the effect of anaerobic digestion (AD), the most common stabilization process for sewage sludge, on the (eco)toxicity of those complex mixtures is poorly studied. In this work, we fill this research gap by applying an effect-based monitoring approach to screen sludge samples (n = 4) from a full-scale sewage treatment plant before and after conventional mesophilic (37 °C) AD using a battery of cell-based in vitro bioassays for four types of hormonal activity: estrogenic, androgenic, progestagenic and glucocorticoid activity, both in agonist and antagonist modes. We detected estrogenic, glucocorticoid and anti-progestagenic activity in all sludge samples. The glucocorticoid and anti-progestagenic activity remained mostly unchanged after AD treatment, but estrogenicity increased three-fold, likely as a result of bioactivation processes in the digestor. This study presents the first report on the concentration and fate of glucocorticoid and anti-progestagenic activity in AD. Future research should apply bioanalytical tools to a wider range of sludge samples to get a better understanding of the typical hormonal activity in sludge and develop effect-based trigger (EBT) values for biosolids to help interpret the risk posed by the hormonal activity detected in sludge
Microplastics in Australian indoor air: Abundance, characteristics, and implications for human exposure
No full textStudies on airborne microplastics (AMPs) have reported higher abundance of AMPs in indoor air compared to outdoors. Most people spend more time indoors compared to outdoors, and it is therefore important to identify and quantify AMPs in indoor air to understand human exposure to AMPs. This exposure can vary among different individuals as they spend their time in different locations and different activity levels, and thus experience different breathing rates. In this study, AMPs ranging from 20–5000 μm were sampled across different indoor sites of Southeast Queensland using an active sampling technique. The highest indoor MP concentration was observed at a childcare site (2.25 ± 0.38 particles/m3), followed by an office (1.20 ± 0.14 particles/m3) and a school (1.03 ± 0.40 particles/m3). The lowest indoor MP concentration was observed inside a vehicle (0.20 ± 0.14 particles/m3), comparable to outdoor concentrations. The only shapes observed were fibers (98%) and fragments. MP fibers ranged from 71 to 4950 μm in length. Polyethylene terephthalate was the prominent polymer type at most sites. Using our measured airborne concentrations as inhaled air concentrations, we calculated the annual human exposure levels to AMPs using scenario-specific activity levels. Males between the ages of 18 to 64 were calculated to have the highest AMP exposure at 3187 ± 594 particles/year, followed by males ≥65 years at 2978 ± 628 particles/year. The lowest exposure of 1928 ± 549 particles/year was calculated for females between the ages of 5 to 17. This study provides the first report on AMPs for various types of indoor locations where individuals spend most of their time. Considering acute, chronic, industrial, and individual susceptibility, more detailed human inhalation exposure levels to AMPs should be estimated for a realistic appraisal of the human health risk, including how much of the inhaled particles are exhaled.Full Tex
Global Transcriptional Analysis of Nontransformed Human Intestinal Epithelial Cells (FHs 74 Int) after Exposure to Selected Drinking Water Disinfection By-Products
No full textBackground: Drinking water disinfection inadvertently leads to the formation of numerous disinfection by-products (DBPs), some of which are cytotoxic, mutagenic, genotoxic, teratogenic, and potential carcinogens both in vitro and in vivo.
Objectives: We investigated alterations to global gene expression (GE) in nontransformed human small intestine epithelial cells (FHs 74 Int) after exposure to six brominated and two chlorinated DBPs: bromoacetic acid (BAA), bromoacetonitrile (BAN), 2,6-dibromo-p-benzoquinone (DBBQ), bromoacetamide (BAM), tribromoacetaldehyde (TBAL), bromate (BrO−3), trichloroacetic acid (TCAA), and trichloroacetaldehyde (TCAL).
Methods: Using whole-genome cDNA microarray technology (Illumina), we examined GE in nontransformed human cells after 4h exposure to DBPs at predetermined equipotent concentrations, identified significant changes in gene expression (p≤0.01), and investigated the relevance of these genes to specific toxicity pathways via gene and pathway enrichment analysis.
Results: Genes related to activation of oxidative stress–responsive pathways exhibited fewer alterations than expected based on prior work, whereas all DBPs induced notable effects on transcription of genes related to immunity and inflammation.
Discussion: Our results suggest that alterations to genes associated with immune and inflammatory pathways play an important role in the potential adverse health effects of exposure to DBPs. The interrelationship between these pathways and the production of reactive oxygen species (ROS) may explain the common occurrence of oxidative stress in other studies exploring DBP toxicity. Finally, transcriptional changes and shared induction of toxicity pathways observed for all DBPs caution of additive effects of mixtures and suggest further assessment of adverse health effects of mixtures is warranted.Full Tex
Using fluorescence-parallel factor analysis for assessing disinfection by-product formation and natural organic matter removal efficiency in secondary treated synthetic drinking waters
No full textParallel factor (PARAFAC) analysis of fluorescence excitation-emission matrices (EEMs) was used to investigate the organic matter and DBP formation characteristics of untreated, primary treated (enhanced coagulation; EC) and secondary treated synthetic waters prepared using a Suwannee River natural organic matter (SR-NOM) isolate. The organic matter was characterised by four different fluorescence components; two humic acid-like (C1 and C2) and two protein-like (C3 and C4). Secondary treatment methods tested, following EC treatment, were; powdered activated carbon (PAC), granular activated carbon (GAC), 0.1% silver-impregnated activated carbon (SIAC), and MIEX® resin. Secondary treatments were more effective at removing natural organic matter (NOM) and fluorescent DBP-precursor components than EC alone. The formation of a suite of 17 DBPs including chlorinated, brominated and iodinated trihalomethanes (THMs), dihaloacetonitriles (DHANs), chloropropanones (CPs), chloral hydrate (CH) and trichloronitromethane (TCNM) was determined after chlorinating water sampled before and after each treatment step. Regression analysis was used to investigate the relationship between peak component fluorescence intensity (FMAX), DBP concentration and speciation, and more commonly used aggregate parameters such as DOC, UV254 and SUVA254. PARAFAC component 1 (C1) was in general a better predictor of DBP formation than other aggregate parameters, and was well correlated (R ≥ 0.80) with all detected DBPs except dibromochloromethane (DBCM) and dibromoacetonitrile (DBAN). These results indicate that the fluorescence-PARAFAC approach could provide a robust analytical tool for predicting DBP formation, and for evaluating the removal of NOM fractions relevant to DBP formation during water treatment
Airborne Microplastics in Indoor and Outdoor Environments of a Developing Country in South Asia: Abundance, Distribution, Morphology and Possible Sources
No full textAirborne microplastics (AMPs) have been reported in indoor and outdoor air in high-income countries and are expected to be a significant contributor to daily microplastic (MP) exposure for human beings. To date, there are only a handful of studies in lower-middle-income countries. In this study, AMPs from 5000 to 50 μm were sampled across selected areas of Sri Lanka using an active sampling technique. Suspected AMPs were further characterized using Fourier transform infrared spectroscopy. MP concentrations were higher indoors compared to outdoor air (0.13-0.93, compared to 0.00-0.23 particles/m3, respectively). The types of indoor MPs were related to indoor-generating sources, and the occupant's lifestyles. The highest outdoor MP abundance was found near an industrial zone, followed by urban and inland locations in high-density areas. The dominant size range of MPs was 100-300 μm, and the only shapes observed indoors and outdoors were fibers (98%) and fragments. Polyethylene terephthalate was the most prominent MP type, followed by polyester, indicating that textile fibers could be the major source of these AMPs. This study provides the first report on AMPs in Sri Lanka. Considering population growth and industrialization, further research should evaluate possible trends and health risks upon inhalation.Full Tex
A field and laboratory manual for sampling, processing and reporting microplastics in coastal and marine environments
No full textGlobal interest in microplastics is increasing, with numerous organisations collecting data on microplastics in the environment. However, disparate sampling, analysis, and reporting methods limit our ability to integrate data, hindering a global understanding of microplastic occurrence, effects and dynamics. Drawing on international directives and collaborations, we present a comprehensive guideline of harmonised and standardised field and laboratory approaches for microplastics in marine and coastal environments. We aim to ensure data consistency and comparability, incorporating the latest methodological developments for investigating and monitoring microplastics in four environmental matrices: sediment, water, biota, and air. A participatory approach brought together 40 researchers with diverse experience, reflecting a broad range of regional and international research. We provide best practice recommendations for sample processing to isolate, quantify and characterise microplastics, along with effective quality assurance and quality control measures. We also include reporting and data release recommendations, to ensure consistency and comparability across datasets. This guideline is endorsed by Ocean Best Practices System. By following these guidelines, and incorporating workflows supporting Findable, Accessible, Interoperable, and Reusable (FAIR) data, diverse stakeholders and practitioners can generate harmonised data essential for decision-making, facilitating a collective ability to synthesise global datasets and support action on microplastics.Nina Wootton, Patrick Reis-Santos, Rachel Przeslawski, Tanveer M. Adyel, Michelle Blewitt, Bradley Clarke, Thomas Crutchett, Anirban Ghose, Sara Hajbane, Mark Hamann, Britta Denise Hardesty, Rumana Hossain, Jennifer L. Lavers, Sophie C. Leterme, Frederic D.L. Leusch, Samantha K. Lynch, Melanie MacGregor, Cherie A. Motti, Warwick Noble, Allyson O'Brien, Thava Palanisami, Elvis D. Okoffo, Kushani Perera, Peter Puskic, Joseph Razzell Hollis, Lauren Roman, Veena Sahajwalla, Marina F. M. Santana, Anastasiia Snigirova, Elise M. Tuuri, Scott P. Wilson, Shima Ziajahromi, Bronwyn M. Gillander
Metabolite profiles of striped marsh frog (Limnodynastes peronii) larvae exposed to the anti-androgenic fungicides vinclozolin and propiconazole are consistent with altered steroidogenesis and oxidative stress
No full textAmphibians use wetlands in urban and agricultural landscapes for breeding, growth and development. Fungicides and other pesticides used in these areas have therefore been identified as potential threats that could contribute towards amphibian population declines. However, relatively little is known about how such chemicals influence sensitive early life-stages or how short episodic exposures influence sub-lethal physiological and metabolic pathways. The present study applied untargeted metabolomics to evaluate effects in early post-hatch amphibian larvae exposed to the anti-androgenic fungicides vinclozolin and propiconazole. Recently hatched (Gosner developmental stage 25) striped marsh frog (Limnodynastes peronii) larvae were exposed for 96 h to vinclozolin at 17.5, 174.8 and 1748.6 nM and propiconazole at 5.8, 58.4 and 584.4 nM. Nuclear Magnetic Resonance (NMR) spectroscopy was performed on polar metabolites obtained from whole-body extracts. Both fungicides altered metabolite profiles compared to control animals at all concentrations tested, and there were notable differences between the two chemicals. Overall responses were consistent with altered steroidogenesis and/or cholesterol metabolism, with inconsistent responses between the two fungicides likely reflecting minor differences in the mechanisms of action of these chemicals. Broad down-regulation of the tricarboxylic acid (TCA) cycle was also observed and is indicative of oxidative stress. Interestingly, formic acid was significantly increased in larvae exposed to vinclozolin but not propiconazole, suggesting this metabolite may serve as a useful biomarker of exposure to androgen-receptor binding anti-androgenic contaminants. This study demonstrates the power of untargeted metabolomics for distinguishing between similarly acting, but distinct, pollutants and for unraveling non-endocrine responses resulting from exposure to known endocrine active contaminants.Griffith Sciences, School of Environment and ScienceFull Tex
