TH&Co routinely conducts site assessments to characterize the nature of surface and subsurface chemical releases.  These assessments involve collection and analysis of:

• groundwater;
• soil;
• soil gas; and
• indoor and outdoor air.

Our understanding of past and current industrial processes allows us to focus our assessments on primary and secondary sources.  This, coupled with our understanding of regulatory requirements and experience in public meetings, allows TH&Co to provide sufficient sample coverage using the appropriate laboratory analytical methods the first time thus eliminating the need for costly sampling remobilizations.

TH&Co personnel are experienced in sample collection/preservation and laboratory submittal methodologies set forth by Federal, State, and Local regulatory agencies and for litigious projects.  Our knowledge of laboratory quality control/quality assurance policies along with regulatory data usability and data quality objective policies minimizes the likelihood that data obtained by TH&Co personnel will be rejected by regulators and/or the court.  This in turn minimizes the likelihood of time and cost inefficiencies associated with resampling.

TH&Co’s extensive experience in conducting and reviewing risk assessments for our private and public clients allow us to develop streamlined site assessment plans that provide the data needed to efficiently move your project toward completion.

• Groundwater Sampling: TH&Co personnel have installed, developed and sampled numerous groundwater monitoring wells using a variety of drilling methods in accordance with regulatory guidance.  TH&Co personnel are experienced in agency-directed no-, low-, and high-flow well purging methods in wells ranging to less than 10 feet to several hundred feet using a variety of sample retrieval methods ranging from passive diffusion bags (PDBs) to dedicated submersible pumps.  Our overall approach and experience in groundwater sampling reduce the likelihood of obtaining false positive and/or false negative results.
• Soil Sampling: TH&Co is experienced in the logging and collection of soil samples to be tested for volatile, semi-volatile, and non-volatile chemicals using numerous sampling techniques including hollow-stem auger drilling and “direct push” technologies such a cone penetrometer test (CPT) rigs.  TH&Co is also experienced in the application of emerging high-resolution technologies such as membrane interface probe (MIP) sampling.
• Soil Gas Sampling: TH&Co has designed and overseen the installation of hundreds of single- and multi-depth soil gas and ‘subslab’ probes in accordance with regulatory guidance. Being a critical risk assessment component, TH&Co personnel are routinely involved with the sampling of soil gas probes and subsequent sample analysis.
• Indoor / Outdoor Air Sampling: TH&Co is involved in numerous projects focused on indoor and outdoor air quality in both residential and commercial/industrial settings.  TH&Co personnel are experienced in the collection of time-integrated air samples in accordance with regulatory risk assessment guidance.