Through water erosion and runoff, sediment-adsorbed atrazine can undergo se
dimentation and accumulation at the bottom of water bodies and become poten
tial sources of atrazine to the water column. The purpose of this study is
to determine the fate and release of atrazine (C-14) to the water column fr
om two simulated undisturbed submerged sediments at two temperature treatme
nts (5 and 24 degrees C) over a 2-year period. Atrazine residue (C-14) was
released from the two sediments and was, primarily, diffusing from the sedi
ment pore water to the water columns. The amount released was affected by s
ediment type and is related to the sediment's adsorption/desorption capacit
y. Larger amounts of residue (C-14) Were released to the water columns at 5
degrees C than at 24 degrees C. Atrazine degraded in the shallow submerged
anaerobic sediment's water columns over the 2-year period. Less than 2% (p
ercent of applied in atrazine equivalent) of extractable atrazine and metab
olites remained in the sediment after 2 years. The amount of nonextractable
atrazine residue (C-14) was significantly higher in sediments at 24 degree
s C than at 5 degrees C. In conclusion, atrazine accumulating in shallow un
disturbed submerged sediments from nonpoint sources would most likely degra
de and/or become nonextractable over time and would have a low probability
of becoming a significant source to the water body. The conditions where ac
cumulation and future release of atrazine have a greater potential to occur
are under very cold temperatures with low adsorption capacity sediments.