PCBs in Cedar Creek

Since 1984 it has been known that 5.1 miles of Cedar Creek are highly contaminated with polychlorinated biphenyls (PCBs). Because PCBs pose risks to both human and environmental health, these toxic man-made substances were banned from production in 1979. In 1990 the Environmental Protection Agency (EPA) listed Cedar Creek as a superfund site, a federally designated region contaminated by hazardous waste. The Wisconsin Department of Natural Resources (WDNR) and the EPA have long been in negotiations with Mercury Marine and Amcast, the parties responsible for the Cedar Creek PCB contamination. In 1995, the responsible parties were ordered to clean up the Cedarburg Ruck Pond, which was heavily contaminated.  Since that time, no other remediation of the site has occurred.  Currently, the WDNR and the responsible parties are embattled in a debate over the companies’ study methodology to assess site contamination, feasibility of cleanup, and human and environmental health risks.

Cedar Creek Superfund Site Background

Location

The Cedar Creek site runs through a suburban residential area located in the city of Cedarburg (Ozaukee County) in southeastern Wisconsin. Specifically, the site covers Mercury Marine’s plant 2, the Amcast facility, and Cedar Creek from below the Ruck Pond dam in downtown Cedarburg to the confluence of the Milwaukee River. This stretch of Cedar Creek includes the Columbia, Wire and Nail, and former Hamilton Ponds.

See map below

Responsible Parties

Contamination of Cedar Creek was caused by Amcast and Mercury Marine. Amcast operates an aluminum casting plant that has served the automotive industry since the 1930’s. Currently, Amcast operates an aluminum and magnesium die-cast facility on Hamilton Avenue.  Previously the company emptied PCB laden waste into storm sewers that led to Hamilton Pond.  Mercury Marine operated a boat engine manufacturing plant on St. John Avenue from 1951 to 1982. The plant used PCB containing fluids that were often washed into floor drains that ultimately led to Ruck Pond on Cedar Creek.

Cleanup History

In 1984 Mercury Marine and the WDNR initiated contamination studies of Cedar Creek. The WDNR has sampled contaminants in fish tissue and creek sediments since 1986. In 1994 storm sewer lines near Ruck Pond were cleaned and sealed to reduce dispersal of contamination. Mercury Marine continued cleanup efforts in 1994 and 1995. They removed three underground storage tanks and over 7,500 cubic yards of contaminated sediment from Ruck Pond. The reclaimed area has been reconstructed and landscaped. The company completed a similar remediation process of Hamilton Pond from 2000 to 2001. 

Failings of Responsible Parties’ Studies

The responsible parties, Mercury Marine and Amcast, have been compelled by the EPA to complete several levels of assessment. The companies are required to complete a remedial investigation (RI) to assess site contamination, a Feasibility Study (FS) to evaluate the viability of cleanup efforts, a Baseline Ecological Risk Assessment (BERA), and Baseline Human Health Risk Assessment (BHHRA) to document current human and environmental risks. The Wisconsin DNR and the responsible parties are currently entwined in a debate over the details of these studies.

The WDNR has identified numerous limitations and shortcomings with the responsible party’s preliminary results. In general, the WDNR has found that the responsible companies “do not apply the same rigor to their data” as DNR staff, and have e omitted data in several circumstances. For example, the companies have selectively omitted data regarding impacted reaches of the Milwaukee River downstream of the contaminated sites. The WDNR holds that the Baseline Risk Assessments need to include the Milwaukee River since Cedar Creek flows directly into the Milwaukee River, and past studies have shown that Cedar Creek is the only source of PCBs impacting the Milwaukee River in Ozaukee County and Northern Milwaukee County. Additionally, the WDNR has identified the importance of targeting specific PCB congeners (chemical configurations) in the study area. These specific congeners can help to reveal lower levels of contamination, which allows for a better assessment of human and environmental health risks.  FMR has been following this issue, and is particularly disturbed that the responsible parties have repeatedly failed to address the comments of the WDNR.  For example, the WDNR has requested that the caged fish used to assess levels of PCBs in wildlife be placed in direct contact with the contaminated sediments to be able to realistically assess the impact of PCBs on local fish populations.  The responsible parties have failed to rectify these major problems with their studies in an attempt to justify that further remediation is not necessary.

For more information on this issue, please contact Cheryl at

(414) 287-0207 ext. 29 or cheryl_nenn@mkeriverkeeper.org

Cedar Creek Superfund Site