During this first collaboration three speakers from each the US and Australia were asked two
pre-supplied questions relating to the regulatory environment in their country, remediation technologies, and fluorine free aqueous film forming foams with a Q&A session at the end. The event was expertly facilitated by Danielle Toase, Environment Manager, Sydney Airport with the speakers including:

• Shalene Thomas, Vice President & Global Emerging Contaminant Program Manager, WSP (US)
• Bill Di Guiseppi, Principal Hydrogeologist, Jacobs (US)
• Kristi Herzer, Environmental Analyst and Technical Program Lead, Vermont Depart of Environmental Conservation (US)
• Dr John Hunt, Senior Technical Adviser, GHD (Australia)
• Andrew Mitchell, NSW Environmental Manager, ADE Consulting (Australia)
• Nigel Holmes, Principal Advisor Incident Management, QLD Department of Environment & Science (Australia)

Following the success of this first event and positive feedback from both ITRC and ALGA members, further events are planned throughout 2023.

The first event was an expert panel on the latest news on microplastics policies, regulations, and research from the US, Australia, and around the globe. The panel included six speakers from the US, Australia and Europe, and compared responses to date which was followed by a discussion on next steps for microplastics.  Patti Reyes, Director ITRC and Matt Potter, CEO ALGA moderated the event which was held on Thursday 23 March 2023 (Video Link).

As part of the PFAS Event Series to held in April and May 2023, ITRC and ALGA will continue its collaboration with the Network for Industrially Coordinated sustainable Land Management in Europe (NICOLE) also participating. The theme of the event series is PFAS Into the Future: Towards 2028 and will commence on the afternoon of Wednesday 26 April 2023 with ITRC trainers providing industry training across key topics including site characterisation, fate and transport, fluorine free foams, treatment technologies, and other important topics. On Thursday 27 April, ITRC representatives will participate in the PFAS Workshop, including discussion of US priorities in relation to PFAS. Finally on the morning of Friday 28 April 2023, ITRC, NICOLE, ALGA and invited delegates will discuss how our organisations can continue to work together and provide our respective member bases with the most value (Further details and registration:  https://landandgroundwater.com/page/pfas-event-series). ITRC will also provide PFAS training in Christchurch and Auckland during the week of 1 May 2023 (Further details and registration: https://landandgroundwater.com/page/pfas-training-new-zealand).

The collaboration between ITRC and ALGA will continue throughout 2023 with further online events, a roundtable follow up at ecoforum/SustRem and regular catch ups between the organisations.

If you have suggestions for online event topics, or themes for our ongoing collaboration, please contact Matt Potter (matthew@landandgroundwater.com), Vicki Pearce (vicki.pearce@ventia.com) or Charles Grimison (Charles.grimison@ventia.com ).

Article Published on 20/04/2023

The statements, analyses, opinions, information and conclusions that may be found in the articles of this publication are those of the author and not of the Australasian Land & Groundwater Association Ltd (ALGA), which only acts in the capacity as publisher. No part of this publication can be regarded as legal advice. Although care has been taken in preparing this publication, neither ALGA nor the author represent or warrant that the information supplied is current, complete or accurate. To the full extent permitted by law, the author and ALGA do not accept any liability, or owe a duty of care, to any person in respect of any such information. No person should rely in any way on the content of this publication and are encouraged to seek independent legal or other professional advice, if required.

In Australia, the Western Australian Department of Water and Environmental Regulation (DWER) interim guidance (DWER 2016 and 2017) adopted recommendations in a consultant report on methods for soil, sediment, groundwater and surface water sampling for PFAS (Geosyntec 2016). Materials recommended to avoid on-site during sampling included:

• Clothing: new clothing; clothing with stain-resistant, rain-resistant, or waterproof coatings/ treated fabric (for example GORE-TEX®); Tyvek® clothing
• Food wrappers: fast food wrappers and containers; pre-wrapped foods and snacks (for example chocolate bars, energy bars, granola bars and potato chips
• Sampling equipment: Teflon® containing or coated field equipment (tubing, bailers, tape and plumbing paste); Teflon® lined lids on containers (for example sample containers, rinsate water storage containers); glass sample containers with lined lids
• Other products: aluminium foil; self-sticking notes and similar office products (for example 3M Post-It notes); waterproof paper, notebooks, and labels; drilling fluid containing PFAS; detergents and decontamination solutions (for example Decon 90® Decontamination Solution); reusable chemical or gel ice packs (for example BlueIce®).

Other recommendations included avoiding use of detergents to clean equipment, avoiding reusing equipment from sites with known or suspected presence of PFAS, and use of new nitrile gloves for each monitoring location.

The Australian PFAS NEMP (HEPA 2018, 2020) largely adopted these recommendations. Additional items to be excluded from use during sampling were recommended, including cosmetics and sunscreen. The PFAS NEMP also made useful suggestions for improving quality assurance/quality control (QAQC) practices such as increasing the rate of field QC measures from 1 in 20 samples to 1 in 10 samples.

In the USA, the Interstate Technology Regulatory Council (ITRC 2020) provided similar guidance to that in the PFAS NEMP or referred to various State-based guidance including the WA DWER 2016 guidance. They also provided additional detail and clarifications, such as ‘In the case of Tyvek® PPE, plain Tyvek® does not contain PFAS while coated Tyvek® does.’ The ITRC guidance usefully noted that not all PFAS containing materials may be able to be eliminated from site, meaning a thorough QAQC program is needed to ensure data quality indicators for cross-contamination are met. For example, rather than avoiding detergents altogether, ITRC recommended that ‘The SDSs of detergents or soaps used in decontamination procedures should be reviewed to ensure fluoro-surfactants are not listed as ingredients.’

While many of these practices are self-evident, questioning whether all these measures are necessary is reasonable and practicable. This is especially so for items required for personal safety such as sunscreen, wet-weather gear and hazmat suits. For this reason, various organisations have tested a range of materials to understand the potential for PFAS to be released from the materials. In most cases the information has not been compiled for publication or remains in industry reports that are not publicly accessible. The discussion below summarises results from a range of sources that have been collected opportunistically. It is not a rigorous review of all available relevant information but is intended to be sufficient to indicate whether more detailed examination of PFAS-specific sampling guidance is warranted, particularly in relation to environmental site investigations.

Studies examining PFAS or fluorine in sampling related materials

Rodowa et al. (2020) systematically investigated potential cross-contamination from field materials. They analysed 66 materials for a suite of PFAS using both conventional LC-MSMS and total fluorine by particle-induced gamma ray emission (PIGE). Very few materials had detectable PFAS (reported LOQ 0.45 µg/m3) despite many having significant fluorine as measured by PIGE (10s to 100s mg F/m3). The authors pointed out that many of the materials with detectable PFAS should not come into direct contact with samples (for example paper towel and notebooks) as has also been noted by others (Bartlett and Davis 2018). Rodowa et al. (2020) concluded that cross-contamination of samples to reach the then EPA health advisory limit of 70 ng/L was not plausible. It is worth considering that the same calculation to contaminate to a lower limit, for example 1 ng/L, might not lead to the same conclusion for all materials, and this could be relevant in some situations. Nevertheless, the Rodowa et al. (2020) study usefully demonstrates few of the materials had conventionally measurable PFAS at all.

Unpublished results for sampling related materials have been presented in conferences and webinars. Lisa Graham from AsureQuality presented results at an ALGA event in New Zealand (Graham 2018). For that study, qualitative determination of fluorine was done using Fourier Transform Infra-Red Spectroscopy (FTIR) and Scanning Electron Microscopy with Energy Dispersive X-ray Spectrometry (SEM-EDX). Fluorine was not detected in a range of materials in the WA DWER guidance including some waterproof clothing, Tyvek, food wrappers, tubing, aluminium foil, detergents (Liquinox and Decon 90) and ice packs. The advice to not use glass containers was also questioned, as has been questioned by other findings (Lath 2019). While this doesn’t rule out PFAS in all such products, it is further evidence that PFAS is not ubiquitous in all materials. Graham (2018) reported PFOA was detected from PTFE plumber’s tape (presumably determined by LC-MSMS) consistent with findings of Rodowa et al. (2020). Graham (2018) also highlighted poor outcomes (wetting of samples) from the common practice of using ice in plastic bags as a means of avoided ice packs.

A presentation by Elizabeth Denly of TRC (Denly 2019) looked at a related suite of materials using LC-MSMS. She reported significant PFAS, especially short chain PFCAs from a range of materials including both PTFE and LDPE tubing, PTFE bladders, field notebook pages and covers, bailer line, water level tape, silastic tubing and nitrile gloves. PFAS were not detected in a range of other products including silicone tubing, aluminum foil, polyethylene bladder, adhesive notes, passive diffusion bag, resealable plastic storage bags, bubble wrap, bentonite and a protein bar wrapper. A similar unpublished study by Envirolab Services found PFAS in some materials previously associated with PFAS, such as waterproof clothing and some, but not all, Tyvek and food wrappers (D. Springer pers. comm. 2022). In that study, PFAS were not detected in sticky notes, waterproof labels and icepacks.

Other investigations are available addressing more specific sets of materials. A study by Bartlett and Davis (2018) provides commentary on issues surrounding PFAS cross contamination during sampling. This study included results of analysis for 17 PFAS in three personal insect repellents. All PFAS were reported as non-detect (<2.5 ng/L) in all three products. These results contrast with findings for agricultural pesticides where PFAS has been reported. For example, Lasee et al. (2022) reported primarily PFOS in a range of insecticides, where a PFAS was not the primary active ingredient, at concentrations up to about 20 mg/kg. Whilst there is potential for PFAS to exist in pesticides, there is indication that personal insect repellents may be less problematic. Confirming by analysis may still be warranted.

A report by GHD (Cooke and Ewing, 2018) provided measured data for a suite of 29 PFAS in a range of sunscreens chosen to include metal spray-cans, plastic spray-bottles and ‘natural’ products. No PFAS were detected in any sample. A report from ADE Consulting (ADE 2020) addressed cross contamination between soil samples collected using a jaw crusher. They concluded that cross contamination was unlikely to be sufficient to change classification of waste soil.

Other studies not aimed at sampling for contaminated sites have identified PFAS and organofluorine in materials that may be relevant to sampling in some situations. This includes cosmetics (e.g. Whitehead et al. 2021) and sprays used for cleaning glasses (Herkert et al. 2022).

Summary

The information complied for this article was not obtained from systematic review. Nevertheless, the information suggests that some materials recommended to be excluded from sampling sites may not have PFAS at such concentrations to be a risk for cross contamination. Some materials were found to have PFAS, and many of these materials, such as PTFE, can be identified and reasonably excluded. Importantly there was evidence that products such as a personal sunscreen and insect repellent are unlikely to contain PFAS and do not need to be avoided. Similarly, the use of water ice in plastic bags, to avoid freezer packs, may not be warranted.

While the information provides some comfort that field quality control measures may potentially be relaxed, there are caveats that need to be noted. Some of the studies involved targeted analyses for set suites of PFAS using LC-MSMS. There is potential for precursor PFAS to be present in products. This may become relevant where other analytical techniques are used such as Total Oxidisable Precursor (TOP) Assay or Total Organic Fluorine (TOF) are used. Also, the finding of PFAS in some relevant materials again stresses the need for strong QAQC practices to identify PFAS cross contamination at concentrations approaching the current limits of reporting. In particular, collecting field blanks and rinsates (and other materials such as drilling fluids) at an appropriate rate is critical, and non-compliances should be investigated, where appropriate.

Call for information

Based on the findings above, further information from industry would be valuable to (i) identify any similar on studies rigorously assessing PFAS in sampling related materials, and (ii) record expert experience for how often blanks and rinsates are returning results above LOR (or even better, LOD) and therefore suggesting false positives are occurring in samples. The ALGA Emerging Contaminants SIG would value your feedback on any of the following questions:

1. Does your organisation implement the full list of sampling recommendations in the DWER guidance and/or the PFAS NEMP?
2. Has your organisation conducted any studies/analyses to assess PFAS in relevant materials used for PFAS sampling?
3. Has your organisation conducted any studies/analyses to assess PFAS in materials/consumables used for drilling and well installation?
4. Has your organisation relied on any studies (either your own or from other organisations’) to justify not following the full list of recommendations in DWER or the PFAS NEMP?
5. How often (as a percentage) do you observe detects of PFAS above LOR in blanks or rinsates?
6. Do you observe any trends in detects in blanks or rinsates according to materials being used or matrices being sampled?
7. How often do you observe PFAS detections in samples where there are no known source(s) of PFAS? Have these detections ever been linked to sampling practices or lab contamination?

Answers can be provided using the button below.

Depending on the strength of any information provided for the above questions, a more detailed analysis may be possible to provide guidance for consultants and regulators.

References

Bartlett SA and Davis KL, 2018. Evaluating PFAS cross contamination issues. Remediation. 28:53–57.  

Cooke E and Ewing J, 2018. PFAS in Sunscreen NEMP or NOPE. CleanUp Conference Proceedings 2018. GHD, Sydney, Australia.

Denly, E, 2019. PFAS Leachability from Sampling Materials: Results of a Recent Study.  New Hampshire Hazardous Waste & Contaminated Sites Conference, September 2019.

DES 2021 https://www.qld.gov.au/environment/management/environmental/incidents/pfas/monitoring-program-report

DWER 2016. Interim Guideline on the Assessment and Management of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) Contaminated Sites Guidelines. February 2016.

DWER 2017. Interim Guideline on the Assessment and Management of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) Contaminated Sites Guidelines, v2.1. January 2017.

Geosyntec (2016) Methodology for soil, sediment, groundwater and surface water sampling and analyses for PFAS investigations

Graham, LA, 2018. Sample Collection for PFAS – Debunking Sampling Guidance Curiosities.  AsureQuality Ltd. Wellington Laboratory.  ALGA Contaminated Land Conference NZ 2018.

HEPA, 2018. PFAS National Environmental Management Plan v1.0, Heads of EPAs Australian and New Zealand, January 2018

HEPA, 2020. PFAS National Environmental Management Plan v2.0, Heads of EPAs Australian and New Zealand, January 2020.

Herkert NJ, Kassotis CD, Zhang S, Han Y, Pulikkal VF, Sun M, Ferguson PL and Stapleton HM 2022. Characterization of Per- and Polyfluorinated Alkyl Substances Present in Commercial Anti-fog Products and Their In Vitro Adipogenic Activity. Environ. Sci. Technol. 56, 1162−1173.

ITRC, 2020. Site Characterization Considerations, Sampling Precautions, and Laboratory Analytical Methods for Per- and Polyfluoroalkyl Substances (PFAS).  ITRC Washington, DC USA.  April 2020.

Lasee S, McDermett K, Kumar N, Guelfo J, Payton P, Yang Z and Anderson TA, 2022 Targeted analysis and Total Oxidizable Precursor assay of several insecticides for PFAS J. Haz. Mat. Letters 3 (2022) 100067.

Supriya, L, Knight ER, Navarro DA, Kookana RS, McLaughlin MJ, 2019. Sorption of PFOA onto different laboratory materials: Filter membranes and centrifuge tubes.  Chemosphere 222:671-678.

Rodowa AE, Christie E, Sedlak J, Peaslee GF, Bogdan D, DiGuiseppi B and Field JA, 2020 Field Sampling Materials Unlikely Source of Contamination for Perfluoroalkyl and Polyfluoroalkyl Substances in Field Samples. Environ. Sci. Technol. Lett. 7, 156−163

Whitehead HD, Venier M, Wu Y, Eastman E, Urbanik S, Diamond ML, Shalin A, Schwartz-Narbonne H, Bruton TA, Blum A, Wang Z, Green M, Tighe M, Wilkinson JT, McGuinness S and Peaslee GF, 2021. Fluorinated Compounds in North American Cosmetics. Environ. Sci. Technol. Lett. 8, 538−544.

Article Published on 20/04/2023

The statements, analyses, opinions, information and conclusions that may be found in the articles of this publication are those of the author and not of the Australasian Land & Groundwater Association Ltd (ALGA), which only acts in the capacity as publisher. No part of this publication can be regarded as legal advice. Although care has been taken in preparing this publication, neither ALGA nor the author represent or warrant that the information supplied is current, complete or accurate. To the full extent permitted by law, the author and ALGA do not accept any liability, or owe a duty of care, to any person in respect of any such information. No person should rely in any way on the content of this publication and are encouraged to seek independent legal or other professional advice, if required.

Hazard Potential

In the environmental management of fuel sites in Australia, it is relevant to consider that not only do current fuels (imported since 2001) have up to 1% MTBE but historical releases contained up to 15% MTBE. Also, relative to the other main petroleum hydrocarbon contaminants of concern (e.g. benzene, toluene, ethylbenzene, and xylene (BTEX)) at petrol sites, MTBE is highly soluble and mobile in aqueous environment and subject to minimal retardation/degradation in groundwater. MTBE groundwater plumes extend past petroleum hydrocarbon plumes. While volatile and a potential for vapour intrusion, it’s high solubility (~51,000 mg/L), MTBE is less volatile from water than BTEX with a Henry’s Law of 0.024 (unitless) an order of magnitude lower than BTEX which range from 0.227 to 0.322.

For human health MTBE can pose hazards from inhalation exposure affecting the respiratory, neurological and hepatic effects based on laboratory animal data. The inhalation Chronic Reference Concentrations (RFCs) range from 3.0 mg/m3 (USEPA IRIS) to 3.6 mg/m3 (ATSDR Draft. 2022). Health effects posed form oral exposures include hepatic, neurological, lymphoreticular, and male reproductive effects. An oral Intermediate Reference Dose (RFD) of 0.6 mg/kg has been derived by (ATSDR Draft. 2022). In addition to health effects poses aesthetics in drinking weater due to its low odour threshold. In drining water, the potential for aesthetic issues would occur at levels lower than levels that could pose health risks. MTBE has shown some evidence of cancer in rats however, it is not consider mutagenic. Environmentally MTBE poses aquatic toxicity to fish and aquatic organisms.

Screening levels are available to address the common groundwater related risks (see Table 1 below):

Australian Occurrence

To provide some perspective on occurrence in groundwater associated with petrol station sites, a review of groundwater monitoring was undertaken of 61 sites where MTBE was part of the analytical suite. This included a review of 1 474 samples from these sites. Of these sites, 31 (52%) results in detected concentrations. A summary of the results is presented in Table 2 below. The highest concentration measured was 7,900 µg/L. However, 95% of the concentrations were below 607 µg/L.

Table 2. MTBE Groundwater Results Summary

Of the sites, the following exceedances were observed:

• 19 of 41 sites (46%) exceed WHO Drinking Water Guideline (odour)
• 1 of 41 sites (2.5%) exceed derived health risk based drinking water value
• 0 of 41 sites exceed CRC CARE ecological guidelines values or vapour intrusion screening level

Discussion

The potential risks are driven potential use of groundwater or degradation of the benficial use of groundwater for drinking (or non-potable) for odour. There is also the potential for the MTBE to affect beneficial groundwater use beyond the petroleum hydrocarbon plume extent that typically would require management (e.g. use restrictions or remediation)

Some lessons learnt from these are:

• Assess MTBE early in the process;
• Late assessment of MTBE can identify un-delineated plumes requiring further assessment Remediation/Mitigation may be driven by MTBE is sensitive receptors near-by, mainly water use ; and
• Assessing remediation options that are suitable for the presence of MTBE, even if it is not the risk driver.

References

Agency for Toxic Substances and Disease Registry (ATSDR). 2022. Toxicological Profile for Methyl tert-Butyl Ether (MTBE). Draft for Public Comment. U.S. Department of Health and Human Services. January.

CRC CARE 2016, Guidance for the assessment, remediation and management of MTBE, CRC CARE Technical Report no. 36, CRC for Contamination Assessment and Remediation of the Environment, Newcastle, Australia.

WHO 1998, Methyl tertiary-butyl ether, Environmental Health Criteria 206, International Programme on Chemical Safety, World Health Organisation, Geneva, Switzerland

USEPA Integrated Risk Information System. https://www.epa.gov/iris

USEPA Vapor Intrusion Screening Levels (VISLs). https://www.epa.gov/vaporintrusion/vapor-intrusion-screening-level-calculator

Article Published on 20/04/2023

The statements, analyses, opinions, information and conclusions that may be found in the articles of this publication are those of the author and not of the Australasian Land & Groundwater Association Ltd (ALGA), which only acts in the capacity as publisher. No part of this publication can be regarded as legal advice. Although care has been taken in preparing this publication, neither ALGA nor the author represent or warrant that the information supplied is current, complete or accurate. To the full extent permitted by law, the author and ALGA do not accept any liability, or owe a duty of care, to any person in respect of any such information. No person should rely in any way on the content of this publication and are encouraged to seek independent legal or other professional advice, if required.

When steel USTs are removed, they are typically de-gassed on site and transported for disposal or recycling at a licensed facility. New fibreglass tanks come with a 30-year internal corrosion warranty however the cost to transport these tanks back to the supplier and have them re-certified so they can be re-used with warranty in place, is greater than the cost of a new tank. For this reason, when fibreglass tanks are removed, they tend to be destroyed in-situ for disposal at landfill. During this process, the leak detection fluid is often lost into the ground. On the premise that this fluid comprises non-toxic constituents, no human health or environmental risk would result from in-ground destruction. However, as these modern fibreglass tanks are usually well within serviceable lives, the chemical properties of interstitial leak detection fluid has not been independently assessed in a remediation framework to GHD’s knowledge.

During remediation works carried out by GHD at a service station site, leak detection fluid from two large (90 kL) fibreglass USTs, installed in 2018, was sampled and analysed to inform disposal options. The results suggested there was more than just food dye and brine in the fluid. A range of volatile organic compounds were detected with high concentrations of acetone (6.5mg/L) and methyl ethyl ketone (MEK; 110 mg/L) as well as petroleum hydrocarbons. These compounds have toxic properties. They are known to depress the central nervous system and be harmful to the kidney. They are highly volatile and are an irritant to the nose and throat when breathed in, in high concentrations. Consultation with the supplier revealed that solvents are used during the construction of a fibreglass UST. It is hypothesized that when the internal cavity was filled with the leak detection solution, acetone and MEK leached from the fibreglass internal surfaces into the leak detection fluid causing these detections.

GHD and our subcontractor, Enviropacific Services (EPS), devised a method to safely remove the leak detection fluid and prevent it entering the environment without having to remove the intact tank with a crane and drain it from the bottom. The devised method allowed approximately 600 litres of toxic leak detection fluid to be removed and safely disposed of at a licensed facility and prevented a potential environmental pollution incident. In future, when decommissioning these types of USTs, consideration should be given to testing the leak detection fluid and removing it prior to UST destruction. In addition, detections of acetone, MEK or other VOCs in groundwater should be evaluated in relation to leak detection fluid as this may alter the conceptual site model for the site especially in cases where there was no other identified solvent source at the site yet solvents have been detected.

Article Published on 20/04/2023

The statements, analyses, opinions, information and conclusions that may be found in the articles of this publication are those of the author and not of the Australasian Land & Groundwater Association Ltd (ALGA), which only acts in the capacity as publisher. No part of this publication can be regarded as legal advice. Although care has been taken in preparing this publication, neither ALGA nor the author represent or warrant that the information supplied is current, complete or accurate. To the full extent permitted by law, the author and ALGA do not accept any liability, or owe a duty of care, to any person in respect of any such information. No person should rely in any way on the content of this publication and are encouraged to seek independent legal or other professional advice, if required.

What are Microplastics?

Plastic is such a versatile material that we can no longer imagine daily life without it. It has been estimated that 9 billion metric tons of plastic have been produced since 1950, and that annual production increases exponentially. However, the disposal and recycling pathways have not been keeping up with the demand and therefore a great proportion of plastic waste accumulates in the environment. Due to its extreme durability, plastic exhibits environmental persistence. Due to weathering and degradation it breaks down over time into small particles, fragments, and fibers – what we know as microplastics.

Additionally, use of personal care products (facewash, toothpaste, etc.) and industry activity (plastic pellets) have resulted in some of the microplastics being released directly into the environment. Although plastics have been in use for over 70 years, the notion that microplastics could be an emerging contaminant is new. Only in 2020, the California State Water Board adopted a definition of 'microplastics in drinking water', which is the first global legally binding definition.

Where can Microplastics be found?

After being discharged into the environment, microplastics undergo normal environmental processes, such as accumulation, degradation, and migration, so they can be now found everywhere. In 2019, the WHO reported that microplastics are widely found in different areas of the environment, including air, fresh water, wastewater, and seawater. Thus, humans are exposed to microplastics through the air we breathe, the water we drink, and the food we eat. The most abundant microplastics found in the environment are Polystyrene (PS), low/high density Polyethylene (LDPE/HDPE), Polyethylene terephthalate (PET), Polyvinyl chloride (PVC), and Polypropylene (PP) which is consistent with the production volumes.

What is the toxicity of Microplastics?

Throughout the past decade, numerous toxicological studies have postulated that microplastics pose significant environmental and health concerns due to their environmental persistence. Further studies have shown that they can be detected in human stools and embryos as well as have adverse effects on biota as cytotoxicity, inflammation, and oxidative damage. Yet, the field is still emerging as the current understanding of microplastic toxicity is limited. Particularly due to the fact that microplastics are a heterogeneously mixed contaminant suite, comprising a vast array of polymers, sizes, morphologies, and hydrophilicities. Additionally, the chemical (e.g., polymer composition, chemical additives, sorption of contaminates from the environment), and biological (pathogens, natural biofilms) characteristics of microplastics influence toxicological outcomes. Thus, more research, is necessary, in order to understand the complexity of the toxicological implication of microplastics and their long-term effects. Simultaneously, current legislative mandates (California and EU) have required regulators to develop strategies to mitigate microplastic pollution and develop health-based thresholds for the protection of human and ecosystem health, but no legal limits have been released yet.

How are Microplastics analysed?

Despite extensive research performed in recent years, the analysis of microplastics is a very new field of analysis. For an extensive analysis, the following information is required: particle enumeration/concentration, polymer type, size, morphology, and colour. Currently, three analysis techniques are being deployed: Microscopy, Spectroscopy (RAMAN/FTIR/LDIR), and Thermal Analysis (Pyrolysis or Thermal Desorption GC-MS). However, as shown in the Figure, not all the methods provide the same results, which makes comparing different methods difficult.
Additionally, there are further challenges due to the lack of certified reference materials and standardised sampling/clean-up procedures. This collectively leads to low reproducibility and accuracy compared to other established methods. Until today, only two standard methods have been published by the California State Water Board for Potable Water.

How can Microplastics be removed from the environment?

Removal methods include physical sorption and filtration, biological removal and ingestion, and chemical treatments. Currently, there is no large-scale solution to remove microplastics. Even our ordinary wastewater treatment plants are not equipped to remove the microplastics, they either tunnel through or end up in the biosolids fraction. And as biosolids are applied to the fields as fertiliser, the microplastics are returned to the environment and increase the load. However, recent studies and inventions showed promising approaches to removing microplastics from waters and optimisations of wastewater treatment plants which is a great way to start.

Article Published on 20/04/2023

The statements, analyses, opinions, information and conclusions that may be found in the articles of this publication are those of the author and not of the Australasian Land & Groundwater Association Ltd (ALGA), which only acts in the capacity as publisher. No part of this publication can be regarded as legal advice. Although care has been taken in preparing this publication, neither ALGA nor the author represent or warrant that the information supplied is current, complete or accurate. To the full extent permitted by law, the author and ALGA do not accept any liability, or owe a duty of care, to any person in respect of any such information. No person should rely in any way on the content of this publication and are encouraged to seek independent legal or other professional advice, if required.