Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity in Different Stream Compartments, Flow Regimes, and Land Uses in Southeast Wisconsin (2006-2009)

An assessment of organic chemicals and aquatic toxicity in streams located near Milwaukee, Wisconsin, indicated
high potential for adverse impacts on aquatic organisms that
could be related to organic waste compounds (OWCs). OWCs
used in agriculture, industry, and households make their way
into surface waters through runoff, leaking septic-conveyance
systems, regulated and unregulated discharges, and combined sewage overflows, among other sources. Many of these compounds are toxic at elevated concentrations and (or)
known to have endocrine-disrupting potential, and often they
occur as complex mixtures. There is still much to be learned
about the chronic exposure effects of these compounds on
aquatic populations.
During 2006–9, the U.S. Geological Survey, in cooperation with the Milwaukee Metropolitan Sewerage District
(MMSD), conducted a study to determine the occurrence
and potential toxicity of OWCs in different stream compartments and flow regimes for streams in the Milwaukee area.
Samples were collected at 17 sites and analyzed for a suite of
69 OWCs. Three types of stream compartments were represented: water column, streambed pore water, and streambed sediment. Water-column samples were subdivided by flow
regime into stormflow and base-flow samples