New concerns over toxic blue-green algae blooms

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The presence of toxic blue-green algae blooms in lakes has become a commonly recognised phenomena in the summer time but scientists have discovered that exposure to cyanobacteria may have another long term effect on wildlife.

Researchers from the University of Tennessee have found that blue-green algae may produce a compound similar to oestrogen which could disrupt the normal activity of reproductive hormones and adversely affect fish, plants and human health.

Theodore Henry and his team of scientists, exposed groups of larval zebrafish to the blue-green algae cells of Microcystis. They found that the fish tested positive for a well-studied oestrogenic biomarker whereas fish exposed to just the toxin that the bacteria produces did not exhibit this biomarker suggesting that the algal blooms produce a previously unrecognized substance which is an oestrogen-like compound that acts as an endocrine disruptor.

Professor Henry said: "The induction of these genes is consistent with presence of an oestrogen and it is possible that many adverse effects may occur in fish populations. From physical feminisation of male fish to behaviour changes; increased environmental oestrogen levels can impact male territorial defending and even their nest-building habit. Environmentally released oestrogen has not been shown to affect reproduction, but studies are still being conducted on the subject."

Professor Henry also commented on the fact that the toxic blooms are a growing concern across the world causing skin rashes, fever and liver damage in humans as well as the noted effects in fish. He called for a revision of environmental monitoring programs to watch for these new substances.