Cadmium transport mediated by soil colloid and dissolved organic matter:A field study
Zhaoli Li , Lixiang Zhou
DOI:
Received March 16, 2009,Revised July 23, 2009, Accepted , Available online
Volume 22,2010,Pages 106-115
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This study investigated the potential role of soil colloids and dissolved organic matter (DOM) in transporting Cd through in situ
undisturbed paddy soil monoliths. Brilliant Blue was used as a tracer to assess the e ect of preferential flow on Cd down migration.
Experimental results showed that deep penetration of Cd and Brilliant Blue into the soil profile took place due to the preferential flow
through macropores, mainly earthworm channels, with much of chemicals thus bypassing the soil matrix. Dye tracer and Cd distribution
within the soil matrix was fairly restricted to several centimeters. Colloid restrained the migration of both dye and Cd in the matrix and
preferential flow area. DOM facilitated the transport of Cd and Brilliant Blue in matrix and macropores by about 10 cm over that of the
control. Pearson’s is correlation analysis revealed strong associations between Brilliant Blue concentrations, exchangeable Cd and total
Cd concentrations in three studied plots indicating that they had taken the same preferential flow pathway.
