Summaries Published in the June 2019 Issue
Maria Vila-Costa, IDAEA-CSIC and Rainer Lohmann, University of Rhode Island
This session, divided into two parts, covered different experimental approaches to determine the physicochemical and biological factors driving the transport and fate of organic pollutants in aquatic systems. The platform presentations and posters studied a wide range of aquatic settings, including lakes, streams, sediment-water interfaces and seawater. The organic pollutants of interest ranged from polar micropollutants (pharmaceutical and personal care products, pesticides, etc.), (methyl)mercury, antimicrobial peptides, some persistent organic pollutants (POPs) and other apolar organic pollutants, such as polycyclic aromatic hydrocarbons. The main subjects covered included: (1) quantification of transformation rates in the field and in laboratory-based incubations, (2) spatial and temporal variation of concentrations and rates in the environment, and (3) internal concentration of pollutants in organisms (mostly in fish but also plankton and turtles, etc). Additionally, methodological innovations to analyze organic pollutants were presented. Of note for the authors presenting, 20% of the participants were candidates for student awards and 60% were female scientists. The session was composed of two presentation blocks that included a total of 11 platform presentations and a large poster session. The first part of the session, mostly devoted to the determination of biotransformation rates in different habitats, included measurements in:
- Lakes Ecosystems. Annie Chalifour from Eawag presented a mass balance study of micropollutants concentrations in Lake Griefensee with biotransformation rates measured in complementary batch-lab experiments. She observed that for the less recalcitrant micropollutants, faster transformation rates occurred under the higher in situ microbial (mainly phytoplanktonic) biomasses, suggesting a more important role of biotransformation versus photodegradation for a large number of compounds. Anna-Lena Rehrl from the Swedish University of Agricultural Sciences measured concentrations of micropollutants along a seasonal and spatial (vertical and horizontal) gradient in the Swedish lake Mälaren. Concentrations of some compounds were closely correlated, indicating a similar source and transport, and some deep samples showed higher concentrations than surface waters, suggesting that the physicochemistry of the lake (stratification), along with biological activity, plays a key role determining MP fate. Heleen de Wit from NIVA presented a study of the dynamics of airborne mercury (Hg) in a northern humic lake with special focus on the role played by the size of dissolved organic matter (DOM) on Hg fate. Differences in the lability of Hg-associated DOM were observed between inlet and outlet streams of the lake, which seems to accumulate in food webs more based on the microbial loop.
- Freshwater Water Column-Sediment Interfaces. Carolin Seller from Eawag analyzed in laboratory-based time-series tests the biotransformation kinetics of micropollutants across different water sediment systems. Results were used to create a mathematical model to estimate biotransformation rates in these systems, correcting the rates by bioavailability and microbial biomass parameters among others. The role of protozoans in degradation was highlighted. Karolina Nowak from TU Berlin used stable isotope approaches to track the microbial turnover of pesticides. Their fate diverged among compounds and included mineralization to CO2, incorporation into biomass with distinction between the different amino acids, and transformation products clearly different depending on whether they underwent an abiotic or biotic transformation.
- Streams. Werner Desiante from Eawag compared the micropollutant biodegradation capacity of river biofilms upstream and downstream from a wastewater treatment plant. Desiante concluded that downstream communities had a higher biodegradation capacity although other factors need to be taken into account, such as bacterial abundance, which are positively correlated to degradation rates. Caroline Davis from ETH Zurich tracked the fate of three antimicrobial peptides (AMPs) in riverine system and distinguished between different types of photochemical transformations, biological (mainly by riverine biofilm bacteria) and sorption. The study concluded that although some transformation rates are really fast, some AMPs persist in the environment.
- Seawater. Belen Gonzalez-Gaya, PIE, University of Basque Country, showed that biodegradation of atmospheric aromatic hydrocarbons into the oligotrophic ocean is a widespread process that plays a key role determining PAHs fate in the water column.
The second block of oral presentations included the determination of concentrations in fish. Georg Radermacher from Fraunhofer IME quantified concentrations of cyclic volatile methylsiloxanes in German wild fish via GC-ICP-MS/MS method. Lijun Han from the China Agricultural University quantified organophosphate esters in fish using a robotic ITSP mini-SPE cleaning step followed by a comparison of three different methods: GC-MS/MS, LC-MS/MS and LC-Flow injection-MS/MS, which was the one giving the highest resolution and lowest contamination. Finally, Terry Bidleman from Umea University was the only speaker on natural (not anthropogenic) but potentially toxic compounds: the concentration of bromophenolic compounds in Nordic macroalgae that are consumed by humans. They play important ecological (positive and negative) roles in the ecosystem. Concentrations of these compounds and their transformation products present a large variability between them as well as addressing potential seasonal variability.
The session finished with two poster highlights. Sean McLaughlin, Smithers Viscient, discussed the use of two different OECD guidelines (301 and 307) to determine the biodegradability of acetaminophen as a model compound. Johannes Schwobel, COSMOlogic, showed how to best predict the bioaccumulation potential of ionizable organic chemicals and suggested that COSMOS-RS could be a useful modeling tool in that regard.
In general, many studies aimed to distinguish the different transformation products, and differentiate between biotic and abiotic process and determine their drivers. A general conclusion in many studies was that there is a current need to open the black box of microorganisms, key degraders of organic pollutants in aquatic systems, to have a better understanding of biodegradation rates. The incorporation of taxonomical and functional information of the microbial communities is underway and calls for more interdisciplinary approaches.
Peter Fantke, Technical University of Denmark
Why Does Substituting Harmful Chemicals Matter?
A worldwide, growing diversity of consumer goods puts more and more pressure on a variety of chemicals that can be used in these goods, including flame-retardants, pesticides, plasticizers, solvents, cleaning agents and the list goes on and on. During the life cycle of consumer goods – from manufacturing to waste handling – chemical exposure can cause negative effects on human and environmental health.
There is a growing need to use safer and more sustainable chemicals in our goods and materials across all sectors. In 2018, the European Chemicals Agency (ECHA) issued a “Strategy to promote substitution to safer chemicals through innovation,” indicating challenges to transition towards safer chemicals, and the European 7th EU Environmental Action Programme has called for a strategy for a non-toxic environment. In addition, the “Sustainable Development Goals” defined by the United Nations call for a broad reduction of chemical pollution and minimization of human and ecological exposure to harmful chemicals as clear targets.
How can chemical pressure on human and environmental health be best linked to advances in producing consumer goods? This question is addressed in the emerging field of “alternatives assessment,” which gains more and more interest as a framework for identifying and evaluating chemicals, materials, processes or behavioral changes that may serve as viable alternatives to using hazardous substances. At the same time, high-throughput screening and prioritization approaches are increasingly becoming available to support the broader phase-out and substitution of harmful chemicals across goods and industry sectors.
However, the multitude of relevant substitution components along with the need for easy-to-use and operational assessment tools currently render it difficult to achieve consistency across data requirements, assessment methods and resulting indicators. This often leads to “regrettable substitutions” in substitution practice, leaving relevant trade-offs between assessment components unaddressed.
What can we learn from advances in green and sustainable chemistry, alternatives assessment and substitution to successfully replace harmful chemicals in goods and materials? The purpose of this session was to discuss challenges and opportunities in substitution methods, to look beyond current practices and build synergies with adjacent fields, such as life cycle assessment, exposure analysis and decision science.
A high relevance of this session was noted through its alignment with an adjacent session on “Substitution of Chemicals of Concern” and a lively and interactive discussion among the more-than-100 session participants.
The session had six presentations that covered the views from different experts and stakeholders from the International Chemical Secretariat (ChemSec); universities in Denmark, Lithuana, Norway, Sweden, Switzerland and the United States; the Environmental Genome Initiative; and European and U.S. environmental and public health agencies. Presentations were accompanied by posters discussing views on advancing substitution practice from the Finnish Environment Institute; Peter Fisk Associates LTD; a Portuguese, a Swiss and two Italian universities; the German Federal Environment Agency; and the European Commission’s Joint Research Centre.
Key points from the six presentations included:
- Anna Lennquist, ChemSec, introduced the session by presenting open access databases and knowledge exchange platforms in support of progressing substitution practice. The use of such databases and platforms was encouraged to overcome challenges related to the introduction of lesser known alternatives to harmful chemicals in various applications.
- Peter Fantke, Denmark Technical University, and his U.S. collaborators proposed how to integrate life cycle impacts into alternatives assessment. They highlighted that indicators for impacts along chemical and product life cycles are essential to uncover relevant tradeoffs. Yet, they noted that simply applying existing life cycle assessment methods is not straightforward, but instead, streamlined and focused identification of relevant impact categories and exposure contexts is needed.
- Semih Oguzcan, Kaunas University of Technology, presented a method for testing an approach combining precautionary risk estimates for workers, consumers and general public in substitution with the aim to encourage substitution practice in Small and Medium Enterprises (SMEs). Concerns were raised that a broader set of indicators is needed to avoid burden shifting across impacts and exposed population groups.
- Ian Cousins, Stockholm University, and his team of international researchers and public stakeholders presented an approach for identifying when the use of various per- and polyfluoroalkyl substances (PFAS) can be phased out. It was highlighted that it is not practical to ban all uses but to evaluate if a use is essential for the functioning of society and to focus substitution efforts systematically on essential uses.
- Katerina Stylianou, University of Michigan, her team and collaborators from the U.S. EPA and the Technical University of Denmark proposed a quantitative screening framework for coupling consumers with environmental exposure for thousands of chemical-product combinations. The need for a consistent mass balance across exposure pathways was emphasized, rendering such a framework suitable for chemical substitution, but also in life cycle impact assessment and high-throughput risk screening and chemical prioritization.
- Ziye Zheng, Umeå University, together with a team from other Swedish and Norwegian research institutions closed this session with a presentation of an assessment framework that includes in silico data across multiple endpoints and that evaluates different multi-criteria decision analysis (MCDA) methods. They highlighted that current hazard data gaps should not prevent us from evaluating alternatives but to close these gaps using in silico based approaches, also including mobility as relevant hazard endpoint.
Main Conclusions From the Session
The session made it very clear that several novel methodological improvements are required to advance and further operationalize alternatives assessment and substitution across sectors.
Life cycle impacts need to be considered using a broader set of environmental and human health indicators to address possible tradeoffs between alternatives. This should, however, be done in a streamlined and focused approach that is consistent with the requirements of a rapid screening substitution, while being quantitative and based on a complete chemical mass balance where possible, in-line with a comparative context of substitution.
Tools and data for assessing hazard are more advanced, while approaches that consider various exposure contexts, thereby making use of high-throughput modeling and in silico-based approaches for filling in data gaps, are becoming more available on both sides.
There are several challenges related to the introduction of lesser known alternatives in substitution, which should be addressed by starting from readily available databases and platforms promoting known and lesser known alternatives. Finally, any substitution effort should be systematically focused on essential uses before committing capacity to assess and introduce any alternative.
Overall, there is an urgent need to look beyond hazard and qualitative assessments in alternatives assessment and chemical substitution in order to address a wider range of impacts and avoid regrettable substitutions. Yet, substitution tools should be easy to use and operational for a broad application in decision support around replacing and phasing out harmful substances across sectors.
Authors’ contact information: email@example.com
Carla Caldeira, European Commission – Joint Research Center (EC-JRC)
The main goal of the session was to present recent methodological developments and applications of stand-alone or integrated life cycle approaches used to assess the sustainability of circular economy. Presentations covered key areas identified in the EU Action Plan for circular economy, namely production, consumption, waste management and market for secondary raw materials.
The session included five platform presentations and three poster spotlights. The main points covered in the five presentations included:
- Elias De Valk, National Institute for Public Health and the Environment suggested that impact assessments can be used to evaluate circular procurement sustainability to: 1) determine for which products or services circular procurement is most beneficial; 2) choose between optional products and services; 3) evaluate the actual effects of the sustainable and circular procurement during and after contract management to strive for further improvement. Life Cycle Analysis (LCA) plays a role in all three aspects but differs with regards to scope, requirements for the inventory and quality assessment.
- The application of the Life Cycle Gap-Analysis was demonstrated by Michael Dieterle, Fraunhofer Institute for Chemical Technology, based on a virtual case study of a lithium-ion battery for e-mobility. This technique analyzes the consequences of product innovations and new technologies regarding both the vision of circular economies and the actual consequences for current life cycle systems.
- Dieuwertje Schrijvers, University of Bordeaux, presented an approach to evaluate the environmental performance of circular strategies, using the market–price ratio between a recycled and a primary product to: 1) identify the functional equivalence of the two product systems and 2) identify the substituted products and processes due to the use or the supply of a recycled product. This approach enables the comparison of two product systems by considering specific market segments and downstream effects of using a recycled product.
- Carla Caldeira, EC-JRC, presented a tool developed for non-LCA expert users to evaluate the effectiveness of food waste prevention actions based on LCA and cost–benefit analysis. The adoption of a life cycle approach minimizes the risk of burden shifting and can support the design of effective food waste prevention actions.
- Preliminary results presented by Francesca Rosa, University of Milano Bicocca, showed that the use of plastic waste in asphalt mixtures improves the asphalt’s structural and environmental performance. The analysis covered the system up to the production plant and included the road construction, maintenance and end of life phases to provide a more comprehensive assessment.
The poster spotlights included:
- Xiaoyu Yan, University of Exeter, presented the Life Cycle Assessment of an alternative method that involves the use of acid mine drainage generating coal waste in a way that produces a leaching solution (lixiviant). This lixiviant can be used to solubilize metals from printed circuit boards taken from electronic waste.
- Carla Rodrigues, University of Coimbra, showed an environmental assessment of an improved foam glass using alternative waste glass streams as raw material and compared these materials with alternative thermal insulation materials available in the market (insulation cork board, EPS, XPS and stone wool). Foam glass has a great potential for improvement in terms of environmental performance as it presents lower impacts than most of the conventional insulation materials.
- Donald Chapman, KU Leuven, presented a life cycle analysis of car-sharing, including both user and provider responses, to estimate the impacts on both resources and the environment. The complex interaction of different effects means that, under certain circumstances, car-sharing may not lead to lower resource use or environmental benefits.
The session illustrated that LCA is a relevant tool in the assessment of the sustainability of circular economy strategies, such as new materials and processes using secondary materials, or in the assessment of food waste prevention actions. Additionally, new methodological approaches were presented to ensure that the assessment is carried out in the most comprehensive manner.
Author’s contact information: firstname.lastname@example.org
Miguel Oliveira, University of Aveiro & CESAM; James Cizdziel, University of Mississippi; Amy Lusher, NIVA Norwegian Institute of Water Research; and Jane Muncke, Food Packaging Forum Foundation
Plastics are used in a wide range of applications and everyday products. As a result of their usage and environmental release, they may undergo multiple degradation processes and form increasingly smaller-sized particles, often ranging down to the nano-size. This session had a total of 58 abstract submissions, including 22 platform presentations, six poster spotlight presentations, five poster corner presentations and 47 posters. Four blocks, containing five to six platform presentations each, were respectively dedicated to the following subjects: Micro(nano)plastics Source and Occurrence, Micro(nano)plastics Sorption and Toxicology, Micro(nano)plastics Determination and Analytical Developments, and Micro(nano)plastics Fate and Approaches to Tackle the Plastics Problem.
These topics attracted considerable attention from the audience with most people staying for the entire session. On average, around 200 people participated in the platform sessions and approximately 30 joined the poster spotlight session. Furthermore, the session was visible through the SETAC Twitter feed under #SETAC_Microplastics.
Conclusions and Key Points
Plastic materials are being released to the environment as a result of their use. Items like fabrics release sizable numbers of particles, which vary according to the type of fabric material and its production processes. Different sizes, shapes, density and polymers may be found in environmental samples of water, sediments and biota. Fibers are among the most commonly reported shapes and polymers, including polyethylene, polystyrene, polypropylene and polyvinyl chloride, which are the chemical constituents most frequently detected. Terrestrial sources, such as wastewater treatment plants discharges and overland and road runoffs, are recognized as important sources for aquatic contamination. New methodologies to increase the efficiency of representative sampling of microplastics in water samples, analysis (e.g., use of high throughput techniques) and resolution were presented as methods that allow a more efficient detection of microplastics in environmental samples (e.g., metal doping, 14C radiotagging). Several studies showed the degradation of microplastics, short-term and generational effects, and species-specific ability to depurate small plastic particles. Presenters discussed the need to standardize information in terms of exposure conditions and method development to isolate, identify and quantify nanoplastics, especially in environmental samples. Relevant biological models and matrices samples (e.g., sea salt) that may provide information on the levels of waterborne microplastics were discussed.
Overall, several keywords summarize the content of the presentations, including microplastics, nanoplastics, adsorption, size, shape, polymer, density, vector, contaminants, depuration, quantification, methodologies, protocols, monitoring and biological effects.
The take-home messages from this session were:
- Time course analysis show that plastic levels have increased in the last years.
- New techniques for quantification and analysis of microplastics are being developed, but their efficiency in real scenarios needs further validation.
- Detection, quantification and analysis of nanoplastics in environmental media remains an unsolved challenge, but first laboratory studies investigating the behavior of nanoplastics in the environment are needed. This further suggests the likely accumulation of nanoplastics in soil.
- Polyethylene terephthalate (PET) microplastics may be a feedstock for syngas production, from which fuels may be produced. This finding promises generation of carbon-neutral fuels if PET is made from renewable sources.
- Improvements and harmonization are still needed with further validation on different complex environmental matrices.
- Bio-based and biodegradable plastics present toxicity similar to convention polymers in in vitro.