The number of horses in Queensland to return positive swabs to arsenic has reached double figures with stewards worried about the trend.

Acting chief steward Daniel Aurisch has again warned trainers about the dangers of arsenic-treated products.

" It is recommended trainers take appropriate measures if they see their horses chewing shavings or fences constructed with arsenic treated timbers, to avoid potential inquiries and disqualification of horses from races," he said..

NSW Northern Rivers galloper Much Deeper has been disqualified for returning a positive to arsenic after winning at Ipswich on December 27.

Stewards did not punish trainer Paul Nipperess after determining the sample was a result of the horse eating shavings treated with arsenic.

It was at least the 10th case in Queensland in the past few years in which a Victorian study has been used to explain the positive swabs.

A report was compiled by the Melbourne University faculty of Veterinary Agricultural Sciences examining the ingestion of wood shavings containing arsenic and the elevated levels achieved.