Changes in manganese and lead in the environment and young children associated with the introduction of MMT in gasoline

This is a 4-year longitudinal study to evaluate changes to the environment and exposure of young children associated with the introduction of methylcyclopentadienyl manganese tricarbonyl (MMT) into Australia in 2000. The cohort includes 57 females and 56 males; age range of 0.29 to 3.9 years. Samples are collected every 6 months from children in residences located at varying distances from major traffic thoroughfares in Sydney. Environmental samples: air, house and day care dustfall, soil, dust sweepings and gasoline. Samples from children: blood, urine, handwipes prior to and after playing outdoors, and a 6-day duplicate diet. All samples are analyzed for a suite of 20 elements using ICP-MS. Results are presented for the first three 6-month sampling periods for Pb and Mn. For dustfall accumulation, there was no significant change over the 3 sampling periods (time) for Pb or Mn, and a positive relationship between 'traffic exposure' (traffic volume and proximity to the road) and Pb but not Mn. For handwipes, Pb and Mn in wipes taken from children after playing outdoors were usually significantly greater than for wipes taken prior to playing. There was no significant association between Pb or Mn in handwipes with traffic exposure. Dustfall accumulation was a significant predictor for Pb in the handwipes, and dust sweepings were a significant predictor of Mn in handwipes. Blood lead (PbB) ranged from 0.6 to 19 ~tg/dL (GM 2.6) (n=269), and manganese in blood (MnB) ranged from 1.8 to 45 txg/L (GM 11.6) (n=254). There was no significant difference between females and males for either mean PbB or MnB; over time there was a significant decline in PbB but no significant change in MnB. The only significant predictor for PbB was dust-fall accumulation. The only significant predictor for MnB was Mn in handwipes prior to playing. At this early stage of the investigation we have not been able to detect any increases in Mn in these environmental samples or blood samples associated with the use of MMT.