Surveys by the State of Illinois list the rivers in the upper DuPage and Salt Creek basins as failing to support the State’s aquatic life designated use. This designation has led to increased scrutiny and restrictions on NPDES permit holders that discharge to these waterways. Sampling and analysis by the DRSCW has determined that high concentrations of polycyclic aromatic hydrocarbons (PAHs) are one factor degrading aquatic communities in these waterways. While PAHs have multiple sources, recent research has determined that parking surfaces treated with refined coal tar (CT) sealant are major sources of PAHs to lake sediment in urbanized areas of the Midwest. DRSCW proposes that it’s NPDES permit holding members voluntarily abstain from the use of CT sealants in all their operational duties.

Issue Aquatic life surveys are used by the State of Illinois to regulate local governments’ NPDES permits. NPDES permit holders are assigned tighter limits on pollutant discharges for river segments which fail to meet designated uses. All assessed segments of the Upper DuPage River and Salt creek fail to meet the aquatic life designated use. DRSCW analysis of river sediments at 42 sites in the Upper DuPage and Salt Creek watersheds found PAH concentrations greater than those known to be harmful to aquatic life at all 42 sites.

DRSCW will be investigating a number of strategies to reduce PAHs in stormwater runoff. Reducing or eliminating the use of refined coal tar sealant is recommended due to the fact that it is increasingly cited in surface water management literature as a principle source of PAH contamination in Midwestern urbanized areas.




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