SOIL LEAD ACCUMULATION ALONGSIDE A NEWLY CONSTRUCTED ROADWAY

Accumulation of lead (Pb) in soil along a new north-south section of Interstate 95 at Beltsville, Md. , was monitored annually between 1971 and 1977. The increase in Pb content of the top 10 cm of soil was closely correlated with cumulative leaded fuel-burning traffic. Of the Pb accumulated between 8 and 50 m from the highway, between 95 and 98% was found within the 8- to 25-m region. Within this zone, the accumulation rate was estimated to be 0. 85 plus or minus 0. 16 mu g Pb/g soil per 10**6 leaded fuel-burning vehicles at the 90% confidence level. Although the fraction of traffic burning leaded fuel decreased from an estimated 94% in 1971 to 73% in 1977, the decline was offset by the increased average daily traffic on the highway and no significant decrease in the rate of Pb accumulation was found through 1977.