30 May 2000
New data could mean OP ban stays

By FWi staff

NEW research linking sheep dip to nervous-system damage should dissuade the government from re-introducing the chemicals, it is claimed.

Researchers say they have evidence that long-term low-level exposure to organophosphate sheep dip damages the brain and nervous system.

This is at odds with a recent report by government advisors which concluded that there was nothing to prove low-level contact with OPs made people ill.

Recently calls have been growing for OP dip, withdrawn in December until safer packaging was designed, to be re-introduced.

The influential House of Commons Agriculture Select Committee said last week the dips should be sold again as long as the safety users not jeopardised.

But pressure group the Pesticides Action Network (PAN) – formerly the Pesticides Trust – claims the new research proves any such plans should be scrapped.

Alison Craig of PAN said new research was throwing up more doubts all the time, and called on government to apply the “precautionary principle”.

This permits a ban in cases where scientific evidence is insufficient, inconclusive or uncertain, to guarantee safety.

“This latest research reveals that the remit of the agriculture committee is last weeks decision was limited,” said Ms Craig.

“There is no assurance that OPs are safe and new evidence is emerging all the time. Surely the precautionary principle should be applied in this case.”

Roger Cook, director of the National Office of Animal Health (NOAH), which represents animal health companies, said he had not seen the research.

But he said the precautionary principle was already applied to OPs. It was why they had been withdrawn until containers could be modified, he added.

The debate was re-ignited by BBCreports on the latest OP research.

Dr Peter Julu, senior research fellow in neurophysiology at Imperial College, London, believes that chronic OP poisoning leaves a unique “fingerprint”.

Dr Julu reported a pattern of damage to nerves that affect the blood supply and nerve damage to the major blood vessels which regulate heartbeat.

His experiments found that patients lacked the capacity to increase or decrease their heart rate according to demand.

The findings showed that they would feel fatigued when not receiving enough blood to meet the demands they were making.

Separate research by Dr Sarah MacKenzie-Ross, a clinical neuropsychologist at University College, London, found evidence of verbal memory impairment.

Problems Dr MacKenzie-Ross found included reading difficulties, reduced mental flexibility, difficulties in processing information, and severe mood swings.

Dr Ross-MacKenzie said the symptoms were consistent to the sub-cortical region of the brain, something she believed was not identified in earlier research.

Mr Cook said that NOAH would welcome a test to “fingerprint” the cause of symptoms associated with OP poisoning.

He said this would be preferable to the current “allegations and circumstantial evidence” surrounding the debate.