Microplastics, toxic substances and new approaches

Micro- and nano plastics

Micro- and nano plastics was one of the most popular topics at this event and several sessions were dedicated to this area of research. These materials occur in many different sizes and shapes in the environment, and these may affect their fate and toxicological behaviour, making it difficult to properly assess their environmental impact. Development of standardised procedures for the physicochemical characterization of micro- and nano plastics is needed and must be followed by appropriate regulatory development concerning the exposure and effect of these materials on the environment and human health.

Persistent, mobile, and toxic substances

Another important topic was persistent, mobile, and toxic substances, also known as PMTs. These substances are characterised by poor degradation in the environment and high mobility between environmental compartments (air, water and soil), as well as their ability to evade sorption-based water treatment processes. Persistency in the environment as a regulatory criterion requires more attention, and a debate exists as to whether the use of chemicals should be limited based on their persistency and degradation rates in the environment. Essential and non-essential use of a substance can be considered as an initial evaluation step to regulate and limit its production. In the case of essential chemicals, procedures to avoid their spread in the environment should be implemented. Among this growing group of PMT chemicals, particular attention was given to perfluoroalkyl substances (PFAS), which, according to the latest classification criteria, include over 6 million compounds. More PFAS will be progressively phased out, but attention should be given to chemicals that may replace these substances to avoid so-called ‘regrettable substitutions’. New technologies such as foam fractionation have shown promising results for the removal of long and medium-chain PFAS, however, short-chain PFAS are still challenging to remove. Great that at KWR we have already been working extensively with these compounds, and we look forward to contributing more to this area of research!

New approach methodologies

New approach methodologies (NAMs) are high-throughput technologies that do not involve test organisms and have received a lot of attention at SETAC as avenues to help integrate toxicological information into decision-making. Their high speed and capacity can help to get a handle on the increasing diversity of chemicals that enter the environment by filling data gaps for new and unknown chemicals, and, as such, have applicability in environmental risk assessment. KWR has been working on risk assessment of chemicals in the aquatic environment following multiple lines of evidence, including NAMs, to safeguard drinking water quality. We will continue to utilize the integration of effect-based methods (bioassays) and computational methods such as quantitative structure-activity relationships (QSARs) to assess the potential risks of chemicals in drinking water and the environment. We look forward to sharing our work again at the next SETAC meeting!