Des Moines TCE Southern Pond Area Removal

 
Site Contact:
Brianne Grant
Alternate OSC

(grant.brianne@epa.gov)

Site Location:
200 SW 16th St.
Des Moines, IA 50309
response.epa.gov/DesMoinesTCESouthernPondAreaRemoval

The site is near the south west corner of the central downtown business district of Des Moines on the east side of a bend in the Raccoon River. In all, the site encompasses more than 200 acres of which the southern pond surface water feature makes up approximately 5 to 10 acres. Former business/manufacturing at the site have included a variety of operations including steel wheel manufacturing, chemical herbicide distribution, and pesticide formulation/distribution processes. Hazardous substances known to have been released at the site include the following: TCE, 1,2-dichloroethene (DCE), and vinyl chloride (found in groundwater); residual pesticides, dioxins, polychlorinated biphenyls (PCBs), and metals (found in shallow soils); and pesticides, dioxins, and PCBs within building construction materials. The site was listed on the NPL in September 1983.

EPA sampling in June 2016 and May 2018 detected aldrin, dieldrin, chlordane, p,p’-Dichlorodiphenyldichloroethane, p,p’-Dichlorodiphenyldichloroethene and p,p’-Dichlorodiphenyltrichloroethane in sediments and nearby soils above ecological screening values.  The zoning in the area has been changed to permit commercial and mixed-use residential redevelopment.  It is anticipated the site itself will be redeveloped for a use that significantly broadens the potential receptor population. The change in ownership and property use prompted the collection and analyses of samples of the south pond sediments for a re-evaluation of human health and environmental threats. 

Analytical results from sediment samples collected at ten locations in the pond and its outflow feature found elevated levels of the following contaminants aldrin, dieldrin, chlordane, 4,4-DDD, 4,4-DDT, 4,4-DDE. Analytical results from surface water samples collected in the SPA found elevated levels of dieldrin. These results establish that releases of hazardous substances as defined by section 101(14) of CERCLA have occurred and have migrated to the SPA. The releases to the SPA are uncontrolled and may migrate further by sediment transport to the drainage ditch leading to the river during flooding events.  Completion of this removal action will address the risks posed by residual contaminants found at the site.