|Lerch, Robert - Bob|
Submitted to: Society of Environmental Toxicology and Chemistry Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/28/1998
Publication Date: N/A
Technical Abstract: The herbicides atrazine, alachlor, cyanazine and metolachlor are common surface water contaminants in Missouri resulting from corn acreage runoff, especially in claypan regions. Several federal agencies have on-going programs to monitor herbicides in Missouri streams by taking periodic water samples. Intermittent runoff events can introduce error into the herbicide erunoff assessment if high concentrations associated with the events are no measured. We evaluated the semipermeable membrane device (SPMD) as a potential alternative or augmentation to grab samples for monitoring herbicides in streams. Duplicate SPMDs were deployed in six streams for a two week period, and grab water samples were taken at the beginning and end of the two week period. The SPMDs were of the common design: a thin layer of lipid (triolein) enclosed in a layflat polyethylene tube. The four herbicides accumulated in the SPMD sampler at amounts consistent with factors controlling SPMD uptake and dissipation rates. The SPMDs show promise as a tool for sequestering atrazine based on the presence of significant levels of atrazine and low standard deviations of the duplicate SPMDs deployed at each site. However, due to the relatively high water solubilities of herbicide compounds and corresponding low Kow's, their accumulation by the SPMD is much less than for compounds such as chlordane, DDT and other higher Kow chemicals. Thus, SPMDs may be useful as a tool for assessing atrazine bioaccumulation in fish or other aquatic species, but they do not serve as an integrated sampler for extended deployment periods.