“While chemists measure the levels of environmental toxins, we biologists monitor their effects. We can use biomarkers to discover these effects before the levels of toxins have become fatal. The increased CBR level in fish is probably caused by chemicals in the water. This means that CBR may be a useful biomarker,” says Eva Albertsson, research student in the Department of Zoology at the University of Gothenburg.

Our sewage treatment plants have been designed to remove nutrients from wastewater, but they are not very good at removing many other substances. Fish downstream of the treatment plants thus live in an environment that is filled with both toxic and non-toxic substances. Eva Albertsson’s thesis presents work carried out at the Gr√•bo treatment plant. It turned out that fish downstream of the plant had higher levels of an enzyme, CBR, in the liver than fish living upstream of the plant. Similar effects were seen also at the Bor√•s treatment plant.

It is known that CBR in humans can protect against oxidative stress, which is a harmful reaction that the body activates in response to certain substances. Thus, the elevated levels of CBR we have seen in fish may not be harmful: they may act as protection. The elevated levels, however, may be an indication that there are substances in the cleaned wastewater that cause oxidative stress, which may in the long term develop to give harmful effects.

The substances that cause oxidative stress are present at different levels in some water, such as, for example, the water that is downstream of a sewage treatment plant. Metals, pesticides and substances that form during incomplete combustion are examples of substances that act in such a manner. Eva Albertsson has studied rainbow trout and eelpout, and shown that fish that are exposed to substances known to cause oxidative stress had higher levels of CBR. This means that the enzyme is suitable for use as a biomarker, an early warning signal, that can be used by scientists and authorities whose task is to monitor the effects of environmental toxins.

The thesis From Proteomic Analysis to Biomarker Application РStudies of Carbonyl Reductase in Fish has been successfully defended at a disputation held at the University of Gothenburg. Supervisor: Lars Förlin
Link to the thesis http://hdl.handle.net/2077/26664

CONTACT:
Eva Albertsson, Department of Zoology at the University of Gothenburg
Tel: +46 31 786 3683
Mobile: +46 73 969 6216
eva.albertsson@zool.gu.se

Portrait of Eva Albertsson. Photo: Björn Magnusson
Figure legend: Eelpout is a species used in the Swedish monitoring of environmental toxins. Since it is a stationary fish, it can be used to couple local releases of environmental toxins to their effects in exposed animals.
Photo: University of Gothenburg/Joachim Sturve