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Solutions For Environmental And Land Remediation

Remediation is the reversing or stopping of environmental damage to soils, waters, air, or building materials. This can involve various remediation options for client consideration on a site-specific basis depending upon contaminant type(s), concentrations, regulatory cleanup standards, local geology and groundwater conditions, access to utilities, property transaction deadlines, planned use or re-use of building or property, available time, and financial stability of the client.

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Upon completion of Site Investigation or Groundwater Assessment Report(s) that has identified the contaminants of concern (COCs) and defined the extend of soil, soil vapor, and/or groundwater contamination limits, GEOTHINK reviews prior data and prepares several remediation solutions and their associated budget costs and limitations. Options may include on-site treatment and encapsulation beneath engineered barriers, on-site soil vapor extraction, on-site groundwater treatment…



GEOTHINK recently celebrated its fifth year in business providing professional environmental and natural resource consulting and contracting services in the Chicagoland region. GEOTHINK offers our Clients solutions to achieving sustainable healthy lands and waters which improves the value of these properties and reduces business risk and regulatory compliance liability. Our goal is to assist Clients by providing practical and effective solutions to comply with numerous regulations and permits that challenge property redevelopment.


land history

Our staff leadership is provided by senior professional geologist and wetland scientist Mr. Thomas Mangan (34+ years of experience) along with other capable staff and qualified contractors that can assist and guide Clients (financial, manufacturers, developers, attorneys, municipalities, county, petroleum producers and pipelines, school districts, and real estate management companies) on how to identify, manage and/or mitigate business environmental liability risk associated with land holdings, business operations, and/or land redevelopment construction. Amongst these GEOTHINK offers many services.


  1. Phase I and II Environmental Site Assessments
  2. Brownfield Redevelopment Evaluations
  3. Site Contamination Investigations
  4. Remediation System Design/Operation
  5. Land History Surveys
  6. Wetland Delineations


Land History

We employ methods and tools to supply timely, relevant and site specific information about the land use history and business operations for agricultural, residential, commercial, and/or industrial property going back to the late 1800s. A historical determination of the ecological and natural resource land history of the subject property can be done by researching the Public Land Survey System records from the US Government surveys conducted in the Mid-West region in the 1820s to 1840s, based upon the township, range and section location of subject property by state. This information can be used in restoration plans to attempt to restore former ecological communities and landscapes.






Years Experience


Clients Helped


Lands Improved

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Kevin McCarthy, CPA, CFE

GEOTHINK is responsive and thorough. The President is "hands on" and explains technical issues in an understandable fashion. I have referred many clients that were dealing with commercial real estate transactions to GeoThink, and have received excellent feedback on their services.

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Bill Nicholas

Former City Manager at City of Sycamore

I knew Tom Mangan and his excellent work before we worked with Geothink. Tom began work on a brownfield project the City of Sycamore tackled in about 2001. His role was to assist the city government in creating plans and specifications to meet EPA expectations and regulations relating to the site. The work nearly a decade, and eventually Tom took his talents to Geothink which helped us complete the job. Tom is technically proficient, very knowledgeable about pertinent public regulations, well-known and respected in the Illinois state regulatory ranks, and very dedicated to the interests of his clients. His easy manner is particularly welcome as entangled regulatory and fiscal issues need sorting. I would strongly recommend his services in the future.

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Jeffrey Lietz

Charles Vincent George Architects

In July 2015 Charles Vincent George Architects (CVG) embarked on a development project with Packey Webb Ford on a 10 acre site along Ogden Avenue in Downers Grove IL. The site was previously a vehicle salvage yard from the 1930’s until the early 1980’s. Sitting vacant for over 30 years and after reviewing numerous failed development attempts from prior owners it became apparent this site was going to be difficult due to the many environmental contaminates and wetland areas. CVG began to interview environmental consultants and was given GeoThink’s (Tom Mangan) information from our Civil consultant, RASmith National. Tom Mangan provided an easy to follow, detailed proposed describing each task required for jurisdictional approval. After being awarded, Tom Mangan jumped both feet in to ensure wetland delineation occurred before close of season and scheduled site contamination investigations. In the end it took GeoThink 8 short months to provide any and all documentation, while working side-by-side with our Civil engineer, to secure State and local jurisdictional approval for construction to commence. GeoThink continues to monitor construction until the ultimate goal of securing a “No Further Remediation” (NFR) letter can be provides by State environmental officials. Tom’s attitude toward service to his client continues without question. That, coupled with his knowledge and experience, makes for an efficiently run approval process for the most complicated of projects. I look forward to future opportunities to work with Tom and GeoThink.

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