Lead in small mammals, plants, and soil at varying distances from a highway.
Abstract
Soil samples were from each side and the central grass strip of highway U.S. Rt. 29 north of Charlottesville, Va., USA, with average flow of 12 470 vehicles daily in 1971, and from a control area 1.3 km from highway Va. Rt. 676. Average Pb content was in soil 138.6 X 10-6 in the central strip and 17.7 X 10-6 in control area; it was in vegetation 109.7 and 6.6 X 10-6. In soil, vegetation and small mammals it decreased with increasing distance from the highway up to the 185-m limit of study. Most of the Pb in vegetation came from air rather than earth. Small mammals in the control area had Pb none to 10 X 10-6 DM of body. At up to 10 m from the highway 15 Microtus pennsylvanicus had Pb 7.2 to 28.5, mean 16.3, 7 Peromyscus leucopus had 4.9 to 12.2, 6.8, and 6 Blarina brevicauda had 7.6 to 63.9, 22.7 X 10-6 DM, probably mainly from diet. Factors in species differences included metabolism, diet, intake, home range and life span. Pb tended to be higher in female than in male Microtus and Blarina, and in older Microtus and Peromyscus. Pb near the highway did not seem to limit numbers of Microtus or Peromyscus but the high Pb concentrations in Blarina could explain its small population size.<new para>ADDITIONAL ABSTRACT:<new para>Lead concentration in soil and plants decreased with increasing distance from U.S. Route 29 North, and varied on either side of the road according to local air movement, and also to driving behaviour on hills. Most Pb in plants was due to air pollution rather than to soil uptake. Small rodents also contained higher Pb levels nearer to the road. The highest amounts in Blarina brevicaudata may have been responsible for its small population. Species differences in mammal contamination were discussed; females tended to contain more than males.