A Study of the Lead Profile of Soil and Vegetation Along Taft/España Avenue, Manila, Philippines

Abstract

Soils and plants sampled along Taft/E,spafi.a Avenue were found to contain high levels of lead. The lead contents tend to decrease with soil depth; increase with proximity to the avenue and traffic density ; and increase with increased obstruction to air circulation.

Much of the lead in the leaves of plants can be removed by washing. This removable lead is exceedingly high in leaves of plants growing in the street islands and within the O to .3 m from the sidewalk of Taft/E,spana Avenue . These values are very much higher than the reported literature value of about 5 ppm for natural lead content of plant leaf and even above the critical limit of 50 ppm .

The level of lead in soils was found exceedingly high in the 0-2 cm surface soil in the street islands and in soils alongside Taft/E.spafla Avenue. This level of lead is maintained high during the dry and rainy season. The 2-5 cm and 5-10 cm below the surface soils acquire as much lead as the 2-cm surface soil during the wet or rainy months. The lowest lead content of the 2-cm surface soil was collected in June at the Manila City Hall site (119 ppm) and the highest at the Quezon City Rotonda site in March (7596 ppm), values very much higher than the reported value of 25 ppm for virgin soil.