Microplastics in waters
Agonizingly dead seabirds with a belly full of microplastic or plastic accumulations as big as islands: Today, practically everyone has seen pictures like these. But there are also pieces of plastic that are barely visible to the eye - microplastics. Recently, according to an announcement for the environmental trade fair ILMAC in Basel, microplastics have also been found in humans.
The danger posed by microplastics has hardly been researched to date. Researchers at Empa have now conducted the world's first risk assessment of microplastics in lakes and rivers. The study concluded that aquatic organisms in Europe are not (yet) at acute risk.
However, these millimeter-sized particles can pose a problem for the environment. Microplastics have arrived in society in two senses, according to a statement on the ILMAC site: "Chemically-analytically, they have already been found in the gastrointestinal tract, blood, lymph and liver of animals can be detected1 and even in the stool of people.2„
Environmental risk given?
Microplastics have also arrived as a political issue for a broad public - an incentive for researchers to shed light and order on the complex area and to highlight possible need for action for the companies involved. Among other things, environmental scientist and Empa researcher Bernd Nowack is looking into the environmental impact of microplastics. Together with Véronique Adam, Nowack has now conducted the world's first risk assessment for fish and other aquatic organisms living in freshwater.
To do this, they compared and evaluated the results from countless studies. To find out whether there is a risk to the environment, the Empa researchers used a method that is established for assessing environmental risks from chemicals. They compared real measured loads of microplastics in water bodies with threshold values for the possible toxic effects in various organisms. If the loads and threshold values overlap, there is indeed an environmental risk.
Result: In Europe, there is currently no danger to the environment, as the concentrations of microplastics actually measured in the waters investigated to date are well below the threshold values. However, it is well known that Asia is particularly affected by the plastic problem. Nowack and Adam then also found an overlap of the loads and the threshold values in the data from Asia, even if this is extremely small.
Regional differences
As these two examples show, the researchers found differences between the various regions of the world in terms of microplastic pollution and the resulting risk to the environment. Especially in regions that have no or only limited functioning wastewater treatment systems, higher environmental concentrations can occur. This is because well-functioning wastewater treatment plants are particularly important for "protecting" the environment from microplastics.
Nowack's conclusion: "At present, there is no indication that microplastics pose a risk to the environment in Europe." However, further studies are needed to definitively rule out negative consequences, he says, as the overall data base is still quite sparse, especially also with regard to local hotspots of microplastics in the environment. For example, he recommends controlled studies using standard methods and complete characterization of the particles.
In any case, his own research group "Environmental Risk Assessment and Management" in Empa's "Technology and Society" department in St. Gallen will continue to pursue the topic. Similar risk assessments for microplastics in soils and a study for the world's oceans are planned. Quantifying microplastic flows into the environment or studying the formation of microplastics during washing and weathering are also current research projects.
We would like to draw your attention to the "Swiss Green & Sustainable Chemistry Days 2019" forum, which will provide you with presentations and news during ILMAC (Tuesday, September 24 to Friday, September 27, 2019). You will find the corresponding program here. The ILMAC Forum is organized by the Swiss Chemical Society.
Original publication:
V. Adam, T. Yang, B. Nowack, "Toward an ecotoxicological risk assessment of microplastics: comparison of available hazard and exposure data in freshwaters," Environmental Toxicology and Chemistry (2018); DOI: 10.1002/etc.4323.
Source: Empa (media release shortened)
