The content of the soils of the wigtownshire area of Scotland

The distribution of lead in 41 soil profiles from a rural area in south‐west Scotland, remote from industrial activity, has been determined and the frequency distribution of both total (mean 30 mg kg −1 , median 15 mg kg −1 ) and extractable lead in the 208 samples plotted diagrammatically. Highly significant correlations were found between total lead and soil depth ( r = −0.43), loss‐on‐ignition ( r =0.59) and acetic acid‐extractable lead ( r =0.76). Surface enrichment is general and almost always most intense where the surface horizons are rich in organic matter. The high correlations obtained between total and EDTA extractable lead ( r =0.86) and ( r =0.89) confirm the close association between total lead and organic matter in soil profiles and suggest that biological cycling is a major factor which contributes to the surface enrichment of lead.