This summary was last updated on June 1, 2001

Lemon Lane is perhaps the most problematic of the sites in that it has PCB contamination deep in the karst which underlies the landfill. Lemon Lane Landfill is in a compound sinkhole (2 sinkholes next to each other) thirty feet deep, and a surface area of 10-11 acres. There are springs in all directions around the landfill that are suspected of transporting contaminants from the landfill. The biggest spring is Illinois Central/Quarry Springs (IC/QS) which is documented to discharge significant amounts of PCB-contaminated sediment and water during periods of high flow.

Most of the high level PCBs have been removed from Lemon Lane, while the remainder has been consolidated and covered on site. In the karst below lurk high concentrations of PCBs, most likely bound to clay and sediments that settle in the fractured limestone. When there is a storm event, the water seeping into the karst mobilizes the PCBs, which migrate rather quickly to the IC/QS, where they emerge in high concentrations. The EPA has built a water filtration plant at the IC Springs, to capture the contaminated water and treat it before releasing it into Clear Creek.

Viacom has taken the position that the water treatment plant is sized too big for the job, and refuses to pay for it. Rather, Viacom has been working on its Lemon Lane Karst Conduit Study. Using RIM (Resistivity Imaging Method) they are trying to map the flows of water at different depths within the limestone. Several new holes were drilled along the east side of the site. They found a clay filled void with high PCB concentrations (as they have in other locations), and some targets were disappointing (dry holes). Monitoring Well 15 in the southeast corner produced up to 3100 ppb PCBs. Pump tests of 2500 gallons of water have shown a lowering of the water table in other monitoring wells up to 600 feet away. They are looking for a main conduit or conduits for the PCBs in the lower limestone, hoping to affect the flow of water and PCBs at the ICS Treatment Plant. (This has not yet occurred, and the fact that water coming from the IC Springs can be alternately clear and turbid implies the possibility of multiple conduits.) They are also exploring the fractured epikarst above the water table where high PCB levels were found.

Final Cap Inspection for Lemon Lane has been completed. The Final Report for Lemon Lane has been issued and will be available at the MCPL PCB Respository.

Earth Tec is working the second draft of the Historical Sampling Report for the EPA. This will allow better analysis of the data for sediment, fish and water that is being collected now and in the future. Viacom had agreed to installing continuous monitoring piezometers at the Landfill.

The EPA is issuing a ROD Amendment which will evaluate options for dealing with the problems remaining at the IC/QS complex. They will look at expanding the treatment plant for additional springs, increasing storm water storage capacity, and purchasing additional processing equipment to lower effluent concentrations. EPA will also look at groundwater extraction near Lemon Lane Landfill to reduce the amount of water making it to the IC Springs, especially during storm events.

Recent Fish Tissue sampling data from Nov. 2000 have been released. Whole fish and filets were taken at Country Club Rd., Fluck Mill Rod. and Strain Ridge Rd. Results showed no significant changes from 1998-2000, and although Viacom wanted to lower the State fish advisories, the State does not foresee changing fish advisories anytime in the near future. Clear Creek remains a Level 5 Advisory, eat no fish. Further Clear Creek sampling is being negotiated with Viacom. Caged fish will be added to test for PCBs in Clear Creek, and the EPA feels there is a need for further fish, water, and sediment testing.