Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Waters are more polluted than tests say: Standard toxicity analyses come up short

30.11.2015

Bodies of water are “sinks”, and thereby bind contaminants particularly well. If even slightly toxic concentrations in water are to be detected, the growth and swimming behavior of small crustaceans, mini-snails and copepods should be used for ecotoxicological assessments. This was the conclusion of a scientist from the TUM, who carried out a number of studies on the subject in cooperation with the University of California in Davis. She also confirmed that it is more informative to test several substances in parallel on various aquatic species, rather than only carrying out individual toxicity tests.

If a small crustacean does not grow properly, this can affect its reproduction. And if it is no longer able to move normally, it cannot flee from predators or from changing temperatures, which eventually has a fatal outcome. In scientific research, these effects are referred to as “sublethal effects”.


The scientists observed several species in the contaminated water body, including the less standard species for these tests, such as mini-snails and copepods.

Photo: Hasenbein

However, worldwide standard methods of pesticide analysis and the risk assessments associated with them only consider the lethal (deadly) effects. For the first time, three studies published in “Ecotoxicology”, “Environmental Science and Pollution Research” and “Environmental Toxicology and Chemistry” demonstrate the sublethal effects on swimming behavior and growth, caused by widely used pesticides on the animals being studied.

Moreover, the results indicate that the substances influence the underwater world for weeks, even if they are no longer detectable using standard methods.

Pesticides become more toxic as a combined package

Another factor is the mix of pesticides: “We looked at the insecticides not individually, but as a mixture, in order to investigate their interaction with one another”, explains lead author Dr. Simone Hasenbein. “In addition, we observed several species in the contaminated water body, including the less standard species for these tests, such as mini-snails and copepods.”

The tests took place over a period of ten days in the laboratory and also for six months in the field. Eventually, significantly negative effects resulting from the combined pesticide pollution in the water were found for twelve of the 15 small invertebrates and ten of the 16 zooplankton species.

“Another point that was considered was how long the insecticide remained detectable in water”, was Dr. Hasenbein’s explanation of the method – “thus, one of the three substances was still detectable after six weeks.”

A clear result delivered by a combination of study series

• Firstly, the laboratory tests provided an indication of the concentrations at which the contaminants influence the growth and swimming behavior of the organisms.
• The field studies proved the long-term effects on an entire ecosystem, its food web and its community structures.

The negative effects on aquatic ecosystems could only be pinned down once all the results were combined. Since the microorganisms being studied can be influenced by the pesticides for much longer than these substances remain detectable, this also leads to the conclusion that bodies of water are far more polluted than all previous research had demonstrated.

Sublethal effects as alarm signals

The changes in the animals which are detectable from their swimming behavior, growth or weight, and which eventually lead to their death (sublethal), are an important indicator of this. To date, however, there is no valid scale showing the point from which, for example, a delay in growth has a fatal outcome for the animal.

Therefore, study author Dr. Hasenbein is advocating this approach in particular: “Sublethal endpoints need to be integrated into the methods used in ambient water monitoring, to allow long-term negative effects on aquatic ecosystems to be detectedreliably, even when the pesticide concentrations in the water are low“, says the scientist.

“A crustacean population which is exposed to low-level contaminant pollution could be more susceptible to invasive species, changes in water temperature or different salt concentrations, because the permanent, low-level pesticide contamination increases stress on the animals.“ This is an important aspect, especially in the light of climate change, and should therefore be taken into consideration in future ecotoxicologic assessments.

Publications:

Hasenbein S, Lawler SP, Geist J, Connon RE.: A long-term assessment of pesticide mixture effects on aquatic invertebrate communities. Environmental Toxicology and Chemistry, 13.11.2015. DOI: 10.1002/etc.3187
http://onlinelibrary.wiley.com/doi/10.1002/etc.3187/full

Hasenbein S, Connon RE, Lawler SP, Geist J.: A comparison of the sublethal and lethal toxicity of four pesticides in Hyalella azteca and Chironomus dilutus, Environmental Science and Pollution Research International, 2015 Aug;22(15):11327-39. doi: 10.1007/s11356-015-4374-1. http://link.springer.com/article/10.1007%2Fs11356-015-4374-1

Hasenbein S, Lawler SP, Geist J, Connon RE: The use of growth and behavioral endpoints to assess the effects of pesticide mixtures upon aquatic organisms. Ecotoxicology 24:746-759, 29.01.2015. DOI: 10.1007/s10646-015-1420-1
http://www.ncbi.nlm.nih.gov/pubmed/25630500

Contact:
Dr. Simone Hasenbein
Technical University of Munich
Chair of Aquatic Systems Biology/
University of California Davis, Dept. of Anatomy, Physiology and Cell Biology
Tel: +1 530 752 3141
Email: shasenbein@ucdavis.edu

Prof. Dr. Jürgen Geist
Chair of Aquatic Systems Biology
Department of Ecology and Ecosystem Management
Mühlenweg 22
D-85354 Freising
Germany
Tel.: +49/8161/71.3947
Email: geist@wzw.tum.de

Weitere Informationen:

http://www.tum.de/en/about-tum/news/press-releases/short/article/32771/

Dr. Ulrich Marsch | Technische Universität München

More articles from Ecology, The Environment and Conservation:

nachricht Safeguarding sustainability through forest certification mapping
27.06.2017 | International Institute for Applied Systems Analysis (IIASA)

nachricht Dune ecosystem modelling
26.06.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making Waves

Computer scientists use wave packet theory to develop realistic, detailed water wave simulations in real time. Their results will be presented at this year’s SIGGRAPH conference.

Think about the last time you were at a lake, river, or the ocean. Remember the ripples of the water, the waves crashing against the rocks, the wake following...

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Nanostructures taste the rainbow

29.06.2017 | Physics and Astronomy

New technique unveils 'matrix' inside tissues and tumors

29.06.2017 | Life Sciences

Cystic fibrosis alters the structure of mucus in airways

29.06.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>