An enzyme in fish can demonstrate environmental toxins

Nov 08, 2011

The level of the enzyme carbonyl reductase (CBR) is elevated in the livers of fish that have been exposed to cleaned wastewater. Scientists at the University of Gothenburg can show that CBR has properties that may make it suitable to be used as a biomarker, an early warning signal of environmental toxins. The aim of the project is to achieve better environmental monitoring.

"While chemists measure the levels of , 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 have been designed to remove nutrients from , 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 Gråbo treatment plant. It turned out that fish downstream of the plant had higher levels of an enzyme, CBR, in the than fish living upstream of the plant. Similar effects were seen also at the Borås 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 , an early , that can be used by scientists and authorities whose task is to monitor the effects of environmental toxins.

Explore further: 3Qs: Game theory and global climate talks

add to favorites email to friend print save as pdf

Related Stories

Potential antifouling substance can cause paler fish

May 10, 2010

The sedative medetomidine has proved effective at inhibiting fouling and is now being trialled by the EU as an ingredient for the antifouling paints of the future. Research at the University of Gothenburg, ...

Medicine residues may threaten fish reproduction

Apr 05, 2010

Researchers at Umea University and the Sahlgrenska Academy at the University of Gothenburg, Sweden, have discovered that traces of many medicines can be found in fish that have been swimming in treated waste water. One such ...

Molecular study shows unexpected effects of toxin

Aug 08, 2011

Scientists from the University of Birmingham studying the effects of the widely-used pesticide fenitrothion, have discovered unexpected cell damage in a common freshwater fish, roach, exposed to the toxin.

Recommended for you

3Qs: Game theory and global climate talks

12 hours ago

Last week, China and the United States announced an ambitious climate agreement aimed at reducing carbon emissions in both countries, a pledge that marks the first time that China has agreed to stop its growing emissions. ...

From hurricanes to drought, LatAm's volatile climate

14 hours ago

Sixteen years ago, Teodoro Acuna Zavala lost nearly everything when Hurricane Mitch ravaged his fields, pouring 10 days of torrential rains on Central America and killing more than 9,000 people.

Nicaragua: Studies say canal impact to be minimal

Nov 20, 2014

Officials said Thursday that studies have determined a $40 billion inter-oceanic canal across Nicaragua will have minimal impact on the environment and society, and construction is to begin next month.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.