ARCADIS saved a confidential client in Upper Michigan an estimated $10-$12 million through completion of a focused investigation and remediation at a Lake Michigan shoreline site. A multi-phase investigation was completed to evaluate affected offshore and onshore areas.  Results of the investigation and subsequent ecological and human health risk studies were used to focus the remediation on the source, resulting in a tremendous savings to the client.  The remedial activities included construction of a temporary surface water containment structure, mechanical and hydraulic sediment dredging, on-site sediment processing, shoreline restoration, fish habitat construction and implementation of a shoreline cleanup program.

Background
 
At a manufacturing site located in Upper Michigan, dried paint sludge materials were disposed of along a Lake Michigan shoreline area.  Based on Toxicity Characteristic Leachate Procedure (TCLP) analytical results (specifically lead results), samples of paint sludge materials exhibited the properties of a characteristic Resource Conservation and Recovery Act (RCRA) hazardous waste. The MDNR placed the site on the Michigan Act 307 (now known as Act 451) list and subsequently issued an unilateral Administrative Order for the site which included performance of interim response (IR) activities and completion of a remedial investigation and feasibility study (RI/FS).  The RI activities included collection of paint sludge fragments from affected shoreline areas and containment and removal of the bulk paint wastes.

The ARCADIS Approach

ARCADIS performed an investigation of the upland, shoreline, and offshore portions of the site to evaluate the nature and extent of paint sludge materials and affected sediments.  Samples of sediment, surface soils, subsurface soils, surface water, and groundwater were collected and analyzed to evaluate potential affects to the quality of these media.  Investigative costs were minimized by completion of soil borings during winter through the ice of Lake Michigan. The investigation resulted in identification of an onshore and offshore area of approximately 1.8 acres containing bulk paint wastes and a length of shoreline greater than 1.5 miles that contained interspersed paint sludge fragments.

Site investigation data were used to evaluate alternatives for remediation of the bulk paint wastes and reduction of risk to human health and the environment. Shoreline cleanup activities were initiated to reduce the volume of fragments washing up along the shoreline. Upon review of applicable technologies and negotiation of the limits and extent of remediation, the alternative selected for shoreline remediation included containment and removal of the bulk paint wastes.  Containment of the bulk paint waste area was completed during 1993 through construction of a 900-foot long synthetically-lined earthen berm. Removal of the bulk paint wastes was completed during 1995 through excavation, dredging, and segregation of the wastes within the bermed area.  The paint wastes and affected sediments were drained and sorted on-site to minimize the volume of potentially hazardous materials.  The paint wastes were stabilized off-site prior to disposal to render the wastes non-hazardous.  Removal of the earthen berm and restoration of the shoreline was completed in 1998 following hydraulic dredging of re-settled solids and completion of a shoreline engineering evaluation.

A human health and ecological risk assessment was completed to address residual paint sludge fragments and detectable lead concentrations in shoreline and offshore sediments.  The risk assessment involved completion and review of sediment toxicity tests, a site-specific Integrated Exposure Uptake Biokinetic (IEUBK) model, and a site-specific Society of Environmental Geochemistry (SEGH) model. Completion of the risk assessment resulted in development of a site-specific criteria for lead that is protective of both human health and the environment. 

Performance Highlights

· Successfully negotiated a focused remedy for the bulk paint wastes resulting in savings of up to $12 million over the originally suggested comprehensive remedy.
 
· Completion of paint sludge and sediment removal under submerged conditions minimized excavation costs and eliminated water treatment costs of more than $1 million.
 
· Implementation of on-site drainage and sorting processes resulted in segregation of hazardous and non-hazardous wastes resulting in a reduction of the volume (and associated disposal costs)of potentially hazardous materials by greater than 50 percent.
 
· Completion of a focused risk assessment resulted in development of a site-specific cleanup criteria that reduced remediation efforts and associated costs.