Losses of endosulfan sulfate represent a small proportion of the applied endosulfan, <0.
Concentrations related to cover treatment more so than decreasing with increasing cover, similar to endosulfan sulfate (and DDE, see discussion).
Thus, DDE concentrations relate more to cover treatment, similar to trifluralin and endosulfan sulfate, than to the amount of cover as was found for [alpha] and [beta] endosulfan.
The [alpha] and [beta] endosulfans were applied over the cover, whereas trifluralin and prometryn were applied before the cover was placed, and DDE and endosulfan sulfate existed in the soil under the coven (Little new endosulfan sulfate appeared to be formed from these recent applications because the soil surface was dry.
Endosulfan sulfate, trifluralin, and DDE concentrations transported on sediment were reduced with higher cover, but related to cover treatment rather than decreasing with increasing cover.
For example, endosulfan sulfate concentrations were reduced by 70% with wheat stubble (mean 27% cover), but by only 53% with cotton trash retained (mean 52% cover), even though these treatments gave similar sediment concentrations (Silburn and Glanville 2002).
Thus, cover treatments that produced a greater proportion of coarse sediment also gave higher concentrations (mg/kg) of trifluralin, prometryn, DDE, and endosulfan sulfate in sediment, and treatments with more suspended sediment had lower concentrations.
Also breakdown products such as endosulfan sulfate may be more likely to form from sorbed parent isomers within aggregates where the parent isomers are less exposed to volatilisation.
Runoff transport of endosulfan sulfate was low because little sulfate was present at this time of the year, but would increase somewhat as the season progressed (Simpson et al.