Rationale and objectives With continued application of pesticides in the Great Lakes basin, nonpoint source pollution of nearshore wetlands is becoming a major concern. Unlike point sources of contamination such as at the outlet of an effluent pipe, nonpoint sources are more difficult to define. These pesticides are frequently transported via sediment, ground or surface water flow from agricultural land into the aquatic ecosystem.
Limited information exists on contamination of sediments by contemporary agricultural pesticides.
Transport of pesticides adsorbed to particulate material may be an important mechanism in pesticide movement from agricultural land to fresh water systems. The deposition of pesticide-carrying particulates could potentially contaminate sediments. The extent of sediment contamination caused by pesticides and the fate of pesticides in sediments in near-shore marshes is unclear. Furthermore, there have been very few studies in agricultural watersheds which address the question of bioavailability and, thus, toxicity of pesticides to organisms which live in or near sediments. A multidisciplinary study was initiated to assess nonpoint source contaminant transport from agricultural land into near-shore zones and wetlands of the Great Lakes Basin.