Trends in blood lead levels in Christchurch (NZ) and environs 1978-85.

Blood lead levels have been monitored since 1974 and have shown a significant decrease (p less than 0.001) from 1978 to 1985 in 2830 subjects from Christchurch and environs. From a baseline in August 1978-81 to August 1985 blood lead levels in a population which had no relevant exposure to lead other than that from the general environment have fallen in adult males and females (greater than 17 years) by 42%, and in school and pre-school children greater than 9 months by 44% and 46% respectively. Reduction of blood lead has accelerated during the last three years. This can be linked to changes in dietary intake and clean up of lead in domestic and industrial environments. Over this decade the lead content of petrol (0.84 g/l) and petrol sales have remained unchanged.