The Government's public health measures to determine acceptable blood lead levels are based on a risk stratified approach focusing mainly on groups of people easily affected by the presence of lead, Secretary for Food & Health Dr Ko Wing-man says.

His remarks follow the release of a report by a Harvard University professor which established that lead levels of five micrograms per decilitre of blood could damage the nervous system.

"The professional opinion available to the Government is that there is no absolute safety level of lead," Dr Ko said, adding that international experts also agree the risk of lead content in drinking water mainly pertains to children in the developmental stage.