Assessment of lead distribution patterns in urban and rural environments

Abstract

The distribution of lead over four (4) square city blocks in a metropolitan area has been determined by analysis of soil, atmospheric particulates, rainwater and vegetation samples taken from four (4) concentric regions. The results revealed that there is a decline in the lead level with increasing distance from the periphery and a sudden increase near the center, suggesting that high levels of lead at the streets are due to vehicular emission while the accumulation near the center of the target area is due to a resulting synergistic buildup. Near the curb the results showed a decrease in lead concentration with distance from traffic lights. However, the profile data revealed some dependency on meteorological conditions, vegetation screening, and traffic light cycling times. Possible consequences of the results with regard to beltways surrounding metropolitan areas are discussed.

The lead concentration profile near an isolated highway in a rural area was also determined and results indicated a steady decline in the level of lead with distance from the highway until a constant background level was reached. Lead levels in the urban area were from two to three times higher than lead levels in the rural area.

A novel, efficient method for the digestion of used filters for subsequent analysis of trace metals in atmospheric particulates is also presented.

Key words:

• vehicular emission
• nonindustrialized community
• traffic flow rate
• lead concentration profile
• synergistic buildup
• digestion procedure
• stripping analysis

Notes

Research trainee at Benedict College during academic year 1974–75.