Blood lead levels in children after phase-out of leaded gasoline in Bombay, India.

The objective of this study was to test for reduction in pediatric blood lead levels (BLLs) in Bombay, India, by comparing BLLs collected in 2002 (after use of leaded gasoline was phased out in Bombay) to those collected in a study conducted by the George Foundation in 1997 (when leaded gasoline was still used in Bombay). We analyzed BLL in a total of 754 children under 12 years of age in two separate sampling campaigns (276 from December 2002 to January 2003 [non-monsoon season]; 478 in June to August 2003 [monsoon season]). BLL was measured using an ESA Lead Care Portable Analyzer. We also measured lead in PM10 samples collected in the study region. These data were compared with a study done by the George Foundation in 1997 before the phase out of leaded gasoline. The George Foundation study reported that 61.8% of the 291 children tested in Bombay had elevated blood lead levels (BLL>or=10 microg/dL). In the present study, 33.2% of the 754 tested children had elevated blood lead levels. The average BLL for the current study population (Geometric Mean=8.36 microg/dL, SD=5.23 microg/dL) was lower than the CDC level of concern (10 microg/dL), with one child diagnosed with lead poisoning (BLL>65 microg/dL). A seasonal trend of BLLs was suggested, with BLL in monsoon season (Geometric Mean=9.1 microg/dL, SD=5.7 microg/dL) higher than that in the non-monsoon season (Geometric Mean=7.3 microg/dL, SD=4.0 microg/dL). A seasonal periodicity of lead in PM10 was found, with lead in monsoon season (Geometric Mean=0.04 microg/m3, SEM=0.000667 microg/m3) lower than that in the non-monsoon season (Geometric Mean=0.38 microg/m3, SEM=0.10 microg/m3). The overall level of airborne dust (PM10) in monsoon season (56.2 microg/m3) was lower than in the non-monsoon season (273.0 microg/m3), presumably due to precipitation. The comparatively higher BLLs in the monsoon season, in the presence of lower air lead levels, suggest ingestion of water or food, with greater lead contamination in the monsoon season, as a possible pathway contributing to elevated BLLs in these children in the monsoon season. These results demonstrate a significant success of the public health system in Bombay, India-achieved by the removal of lead from gasoline. The emphasis should shift in the study region towards sources of lead exposure other than leaded gasoline (lead in paints, lead in Herbal medicines and lead in Kohl).