The Foundation for Baltic and East European Studies

Endocrine disruption in fish: Risk identification, development of biomarkers and assessment of risk levels in the Baltic Sea.

Field: Miljövetenskap, molekylärbiologi
Project leader: Inger Porsch Hällström
Starting year: 2009
Project type: Project

Endocrine disrupting chemicals (EDCs) interfere with the function of hormone systems of vertebrates and several invertebrate species. A wide variety of EDCs from industrial contaminations and municipal wastewaters are found in aquatic environments. Female estrogens and synthetic estrogens used for birth control are important contributors to the EDC load. Evidence from field studies suggests relationship between environmental EDC exposures and developmental and reproductive alterations in fish, including feminisation of male fish living downstream of sewage treatment plants.

Effects of estrogenic chemicals on reproductive variables, such as abnormal gonad structure and differentiation, intersexuality and sex reversal, decreased sperm count and expression of egg yolk protein in males are well established in many fish species. During the past years, studies in mammals and to some extent in fish have shown that EDC exposure during development affect not only fertility and reproduction, but also brain development and sexual and non-sexual behaviour, the immune system, metabolic functions, and increase the risk for disease later in life. Furthermore, the changes induced in the developing organism seems to be to a large extent irreversible, and new experimental data, so far on rodents only, indicate that the effects of treatment can be transmitted, by epigenetic mechanisms, to offspring several generations later. In light of possible trans-generational transmission of effects, it cannot be excluded that EDCs can affect long-term fitness in wildlife and human.

In the present project, we want to study if transgenerational effects of EDCs can be identified also in fish. We will in connection to studies of reproductive and non-reproductive behaviours search for new biomarkers to identify inherited epigenetic changes. These biomarkers will later on be used to monitor the Baltic marine ecosystem for signs of multigenerational insult by endocrine disruption. As biomarkers to detect persistent effects of EDCs in wild populations are scare they will be useful even if trans-generational effects are not present. The following three main questions will be addressed: – Can EDCs give reproduction disturbing transgenerational effects in fish? – Can biomarkers of the persistent changes caused by EDCs be identified? – Do the persistent changes lead to trans-generational effects? – Can these biomarkers be used to indicate reproduction disturbances in natural fish populations?