Lead pollution from a factory manufacturing anti-knock compounds.

Abstract

IN spite of the present discussion of lead pollution, little attention has been paid to pollution from factories manufacturing anti-knock compounds which consist of tetraethyl and tetramethyl lead. In a study of the edaphic factors affecting certain grassland communities in Cheshire, I found significant levels of lead in vegetation close to such a factory. This prompted a study of the fallout from this factory, which is surrounded by a variety of habitats, including coniferous and deciduous woodland, scrub and agricultural grasslands. The study area was a thin strip of deciduous woodland running approximately due east of the factory; it was largely open birch woodland with a well developed field layer of grass species. Ground layer bryophytes were less well represented; these are good accumulators of airborne metallic elements2,4 and Goodman and Roberts5 have used epiphitic material of Hypnum cupressiforme as an indicator of non-ferrous metals in the air in the Swansea area. Epiphytes are poorly developed in the area of Cheshire studied owing to the sulphur dioxide content of the air (125 µg/m3 from analysis of epiphyte communities6). Because the species composition varied considerably along the transect, no single moss species could be sampled at all sites. Species found in abundance at the sample sites were collected and their mean lead content was taken as a measure of the lead accumulated in the ground layer.