High blood lead levels can impair behavioural and intellectual development.

The family of six-year-old Stella Hare has already served a notice of claim for damages on mining company Xstrata, its subsidiary Mt Isa Mines, Mt Isa City Council and the Queensland Government over Stella's brain and nervous system injuries allegedly linked to lead exposure.

Queensland Health senior director of population health Linda Selvey said results showed 11.3 per cent of the total sample of 400 children aged one to four had elevated blood lead levels, greater than 10 micrograms per decilitre.

Dr Selvey said the average level was five, one was as low as 1.3 and the highest was 31.5.

"With healthier lifestyles, improved dust control and continued monitoring, 11 of the 45 identified children have since had their lead levels drop to below the alert level of 10," Dr Selvey said.

"It's very important to ensure that lead levels in children are as low as possible, and as soon as the elevated lead results became known, Queensland Health began actively case managing these children and assisting their families to bring those levels down to below 10."

Dr Selvey said the tests conducted over 2006 and 2007 showed overall there was "no evidence that any particular part of the city has higher lead levels than others".

"The good news is blood lead levels can be naturally reduced by introducing a few practical lifestyle and household measures such as reducing soil exposure, having better diets and keeping dust levels within the house low," Dr Selvey said.

About 70 per cent of the children tested had eaten soil, 91 per cent played in bare soil, 42 per cent sucked their thumb, and 77 per cent owned pets such as dogs which exposed them to more dust.