trace metals.Atmospheric deposition was the most quantitatively important
anthropogenic Pb source, which contributed 38-49% of the
total sediment pollution and had an average contribution rate
of 43.7%.The clusters in farther distances were

mainly chemical fertilizer and livestock manure samples, in-
dicating that they did not substantially contribute to watershed

sediment pollution by Pb. On the other hand, the river sedi-
ment cluster was very near to the concentrated clusters for

background soil and atmospheric deposition samples.Different Pb sources were also quantitatively discrim-
inated by using Isosource.