Development of a Tier-1 assay for effects of plant-incorporated protectant (PIPs) in aquatic systems on leaf-consuming shredders

Movement of transgenic crop debris into streams may expose non-target aquatic shredding organisms to plant-incorporated protectants (PIPs).  Tier-1 testing, which uses purified PIPs applied to food to directly asses effects on non-target organisms, is complicated in aquatic systems because PIPs will disperse off food once submerged in water.  To develop a solution to this problem for aquatic shredding organisms, we developed an assay based on retention of PIPs by polymer coatings.  Food coated with a protein- or carbohydrate-based polymer was fed to amphipods Hyalella azteca.  H. azteca performance as survivorship and mass was measured to determine effects of the polymers with no PIPs present.  Rhodamine B (RB) dye was then used as a PIP substitute.  RB concentration was measured in water samples to determine retention efficacy of the polymer coatings.  The most efficient polymer will be useful in future tests of lethal and sub-lethal effects of PIPs without the influence of plant tissue effects.