University of Gothenburg
University of Gothenburg
The studies showed changes in the zebrafish fry after the chemical exposures.
The studies showed changes in the zebrafish fry after the chemical exposures.
Photo: Mostphotos
  2. News and events
  3. Find news
  4. Chemical cocktail impacts the growth and behaviour of fish

Chemical cocktail impacts the growth and behaviour of fish

Published
at
The Faculty of
Science

Chemicals are continually spread in the environment, and both humans and animals face constant exposure. New studies on zebrafish show that endocrine disrupting chemicals do not just affect adult fish but also their larvae, including impacting their behaviour.

Some chemicals can interfere with an organism’s hormones, thus impacting important processes like growth and brain development.

Environmental toxins often also occur as multichemical mixtures in our environment, making them challenging to study.

“The starting point for my studies has been the EU project ECD-MixRisk and the Swedish SELMA study from Karlstad University, which showed that mixtures of Endocrine Disrupting Chemicals (ECDs) measured in pregnant women are linked to negative effects on their children, including birth weight and brain development,” says Lina Birgersson, author of a new dissertation.

The studies are a part of an extensive EU project

Lina Birgersson’s studies are part of the EU project ECD-MixRisk, which studies the impact of ECD mixtures experimentally in both cell and animal models. The EU project includes studies in epidemiology, biostatistics, chemistry, experimental biology and risk assessment.

Birgersson has conducted lab experiments with zebrafish and field studies with perch in polluted Swedish lakes. She has looked at the effects on zebrafish larvae after short-term exposure to three different EDC mixtures.

“My studies showed that EDC mixtures impact genes related to thyroid function, affecting how zebrafish larvae swim. In studies with one of the mixtures, we saw that the larvae initially became hyperactive and then later swam less than the control group.”

The chemical mixtures impact swimming

For one of the mixtures, effects were noted at concentrations just 10–100 times lower than the average concentrations measured in pregnant women.

“In the studies, we could see changes to the larvae after exposure to the chemicals. They were more hyperactive and we saw changes in genes linked to thyroid function, which regulates growth and brain development at an early stage.”

The immune system was also affected

As a complement, Birgersson also studied possible effects of EDCs on the ecosystem. In a field study outside of Ronneby, she examined wild perch in lakes polluted with highly fluorinated substances (PFASs) from fire suppressants from a nearby military facility.

“We found that lifelong exposure to PFASs in polluted lakes can impact both thyroid function and the immune system among wild perch. PFASs are a known group of EDCs found in fire suppressants, cosmetics and non-stick surfaces on frying pans.”

Contact: Lina Birgersson, Department of Biological and Environmental Sciences, University of Gothenburg, mobile: +46 (0)76-815 92 91, email: lina.birgersson@bioenv.gu.se

Alternate contact: Joachim Sturve, professor at the Department of Biological and Environmental Sciences, University of Gothenburg, +46-(0)31-786 36 88, joachim.sturve@bioenv.gu.se.

Supervisor: Joachim Sturve

Title of dissertation: Effects of mixtures of endocrine disrupting chemicals – Thyroid disruption and behavioural effects in fish models

Digital publishing: http://hdl.handle.net/2077/70218

About the research

The fish were exposed at early stages of development and the larvae’s behaviour was tested. Organisms are particularly sensitive to EDCs if exposed at early development stages. The critical mixtures used in the experiments contained several phthalates, perfluorinated chemicals and bisphenol A and triclosan.
The studies were conducted as part of the EU project EDC-MixRisk, which recently resulted in an article in Science. In the article, the researchers were able to find support for a suspected risk for child language development and developed new principles for risk assessment of chemical mixtures.

The ECD-MixRisk study
The study was a collaboration between seven Swedish and six international high education institutions and was conducted in three steps. The first step identified a mixture of chemicals in blood and urine of pregnant women based on the SELMA study from Karlstad University. These could be linked to delayed language development in the children. The critical mixture included several phthalates, bisphenol A and perfluorinated chemicals.
In the second step, experimental studies examined the connection between human-relevant levels of these mixtures and endocrine disruption or other biological mechanisms.
The third step used the findings from the experimental studies to develop new principles to assess risks for EDC mixtures.

Read more: Exposure to chemical mixtures during pregnancy linked to delayed language development | Uppsala University (mynewsdesk.com)

Link to article in Science: https://www.science.org/doi/10.1126/science.abe8244

Area
Science and Information
Technology
Press
release
Last modified