Assessment of atmospheric lead exposure on children in urban areas, Malaysia.

Abstract

An exposure assessment of atmospheric lead was made on the children in the urban and suburban areas of K. Lumpur by using the indirect method of assessment. Levels of lead in the ambient air, the indoor air, the housedust lead and the topsoil were determined. Questionnaires were used to obtain the daily activity pattern of the children. Urine lead was measured to determine the relationship with exposure. The main source of atmospheric lead was the combustion of leaded gasoline from automobiles. The mean ambient lead in the urban areas was still below the WHO guidelines of 1.5 $\mu$g/m$\sp3$. High lead levels were also found in the dust and soil sampled from the urban areas. There was a statistically significant relationship between the ambient lead and the indoor lead levels in the urban areas. Therefore, outdoor lead particles were transported indoor. The ratio of the indoor to the outdoor lead ranged from 0.3-0.5. The inhalation exposure from indoor air was a dominant route of exposure. The respirable indoor lead was mainly made up of water and dilute acid soluble fractions. The children in both areas were highly exposed to the dilute acid soluble lead fractions from the indoor air. The exposure and uptake through the inhalation were higher than the ingestion route. The inhalation exposure was above the U.S. inhalation baseline of 500 ng/day for 2 year old. The inhalation exposure, total uptake and body burden for lead in the urban children were twice higher than the suburban children. Urine lead levels were significantly related to the lead levels in the air and the inhalation exposure. Total lead uptake and urine lead has no association with the selected social factors except for their house location.