PSU-USGS study improves the understanding of how pesticides are transported within Oregon coastal watersheds

Diffuse pollutant sources, such as those associated with forest practices, are difficult to trace and hard to quantify. The cumulative effects of diffuse pollutant sources, however, can be examined by tracking their occurrence and bioaccumulation in filter feeding organisms such as bivalves and with passive water samplers. The Portland State University- USGS partnership used both approaches to understand how diffuse pollutants from diverse land uses affect coastal species and ecosystems. The results from this study are available here.

The eight watersheds within Oregon’s coastal zone selected for this study represent a range of forestland management activities across different ownership types. Four pesticide compounds commonly applied to commercial forestlands in those watersheds (atrazine, hexazinone, sulfometuron-methyl, and metsulfuron-methyl) were detected within the tissues of filter-feeding bivalves and by passive water samplers in stream and estuarine habitats located considerable distances downstream of the application areas. The findings from this study point to the role that management practices play in controlling the transport of potentially toxic compounds throughout the Oregon Coast Range.