Tainted fish 'harm anglers' brains'

Contaminated: Study centred on Lake Michigan

Sport fishermen who regularly eat their catch from one of the US Great Lakes may be suffering from chemical poisoning, tests have found.

Lake Michigan is thought to be heavily contaminated with chemicals called PCBs, which do not naturally break down and can accumulate in tissues for decades.

Since 1992, researchers from the University of Illinois College of Veterinary Medicine have been studying sport anglers who eat at least 24lbs of fish a year.

The results of their research suggest a significant mental decline.

They found that many had high levels of PCBs in their blood, and these fishermen had difficulties recalling a story told to them just half an hour beforehand.

Adult brains

Their performance in word-learning tests was also far worse than their peers.

These are the first study results suggesting that PCBs may have this affect on the adult brain.

Previous studies have focused on the consequences of PCB exposure to the developing brain of the foetus.

PCBs were widely used in electrical components and in lubricants, paints and varnishes until they were banned in the late 1970s.

However, their persistence in the environment is still giving cause for concern.

Fish pick up the chemicals released into water supplies and store them in fatty tissue.

We're worried about other chemicals which can accumulate in human tissue

Dr Michael Warhurst

Dr Susan Schantz, who led the study, said: "This suggests, for the first time, that PCB body burdens in adulthood may be associated with impairments in certain aspects of memory and learning.

"It had been assumed that mature adults are less susceptible than are developing foetuses - this may not be the case."

Friends of the Earth is running a campaign for more regulation of chemicals which might prove a hazard to human health.

Dr Michael Warhurst, who runs the campaign, said: "We've known for some time that PCBs have an impact on the development of children, but if it's true that they have an effect on adults, that's a significant finding.

"However, we're worried about other chemicals which can accumulate in human tissue.

"Although there is no current evidence of an effect on human health, science often takes time to come up with this."

EU officials are discussing the threat posed by this type of chemicals at a meeting on Thursday and Friday, and campaigners are hopeful that new regulations can be put forward.

The study is to be published in the journal Environmental Health Perspectives.