Environment Many chemicals are undetected in water bodies
For many chemicals in bodies of water, no or only inadequate measurement values are available. This has been proven by a German research team for the USA and reported in the journal "Science".
21.06.2025, 06:12
SDA
The five-member team from the Rhineland-Palatinate University of Technology Kaiserslautern-Landau (RPTU) writes that only 0.52 percent of the approximately 297,000 potentially environmentally relevant chemicals in the US Environmental Protection Agency's database have sufficient data on both their occurrence in water and their effects.
In the past, there was a lack of data on toxicity, but today there is a lack of monitoring data. "The ever-increasing speed at which new chemicals are released into the environment poses a challenge for the assessment of environmental risks."
DDT was also overlooked
"Without monitoring the occurrence and distribution of most chemicals, there is still the possibility that in some cases significant environmental hazards will be overlooked," the study states. Historically, this has already been the case, for example with the insecticide DDT or, more recently, with the chemical group PFAS, which is used in many everyday products. "This shows how the quality of official water monitoring can influence assessments of the risks of chemicals," explains the senior author of the study, Ralf Schulz. The researchers only looked at the impact on aquatic ecosystems, not on human health.
Some substances are already toxic to aquatic life in concentrations that cannot yet be detected, the team writes. This is particularly pronounced in the case of insecticides, especially the group of pyrethroids. They are very toxic to many insect larvae, but also to fish and other aquatic organisms. Many relevant pyrethroid concentrations remain undetected as part of regular monitoring programs, the researchers write with a view to the USA.
Number of chemicals on the rise
"US water monitoring is considered the most comprehensive program for recording water quality over large spatial and temporal scales," the researchers write. Other regions, such as the EU, have less comprehensive or no monitoring programs or no publicly available data. "Today, the monitoring of surface water quality faces a double challenge: on the one hand, the sharp increase in the use of chemicals and, on the other, the lack of highly sensitive analytical methods for highly toxic substances in regular studies."
Only recently has a method been developed in Switzerland that is sufficiently sensitive to detect even the very low but already toxic concentrations of pyrethroids, said the Uba spokesperson. According to the spokesperson, assessment gaps in the EU approval system for plant protection products play an important role in the current inadequate protection of water bodies.
