ENVIRONMENTAL INVESTIGATIONS

Soil and groundwater investigations are critical to delineating the extent of contamination at a site, developing remediation strategies, achieving site closure and improving property value. If during an environmental site investigation it is determined that the soil and/or groundwater has been impacted, remediation must be conducted to bring the site into compliance with applicable state and federal regulations. This process clears the title and removes the environmental liabilities attached to the property. Most property transactions will not close until the remedial process has been completed. NWATS provides the expertise for achieving the ultimate goal of obtaining a No Further Action (NFA) determination for the property. 

Monitoring groundwater quality and understanding aquifer characteristics can aid in detecting contamination before it becomes a problem. The appropriate type of monitoring network and the design of the monitoring system depends upon the hydrogeologic framework, contamination sources, and past chemical waste handling practices. There are four basic types of groundwater monitoring systems: ambient monitoring, source monitoring, enforcement monitoring, and research monitoring. Research monitoring includes the installation and sampling of wells for the detection of contaminants and evaluating the cause and effect between groundwater quality and specific land-use activities.

Remediation of the groundwater requires assessing  the groundwater contaminant concentrations in the aquifer over time for assessing the status of a contaminant plume. Monitoring well data is used to delineate the extent of the plume and calculate travel times within an impacted aquifer and to evaluate the risk to groundwater receptors. NWATS has the expertise for optimizing monitoring well placement and construction, aquifer characterization, remedial design, and monitoring well data evaluation to meet the groundwater remediation goals of the site.

All persons are required to properly manage contaminated soil and water that they uncover or disturb, even if they are not the party responsible for the contamination under the MPCA Brownfields Program. The program consists of two integrated programs, the Petroleum Brownfield Program that handles strictly petroleum contamination, and the Voluntary Investigation and Cleanup (VIC) Program that handles hazardous substance contamination. NWATS provides the environmental investigation services related to the investigation and cleanup of such properties through the development and implementation of Construction Contingency Plans (CCP), Soil Management Plans (SMP), Remedial Action Plans (RAP) and subsequent Implementation Reports for acquiring No Further Action determinations from the MPCA for the contaminated media.

A Phase II Environmental Site Assessment (ESA) is conducted to determine whether there was a past release of a hazardous substance or substances to the soil or sub-surface at the property. A representative quantity of soil and groundwater samples are collected by an environmental professional and analyzed for hazardous chemicals that may occur at the property. NWATS provides the professional services necessary for completing an environmental investigation that focuses on evaluating the presence and extent of contamination at the property.

At sites where petroleum contamination of the soil and/or groundwater occur, an LSI is completed to evaluate the risk posed from the petroleum release. Soil and groundwater contamination assessments are conducted by collecting samples of each of the media and determining the magnitude and extent of the contamination. The information collected during the LSI helps determine whether a remedial investigation or RI is warranted.

Remedial investigations are conducted to delineate the horizontal and vertical extent of groundwater contamination within an aquifer and evaluate the risk posed by the petroleum contamination to groundwater receptors. An RI is required if the LSI determines that: • an aquifer has or likely has been contaminated above drinking water standards or 1 mg/L GRO or DRO. • surface water has or likely has been contaminated above applicable surface water standards or 1 mg/L GRO/DRO. • Mobile liquid petroleum is encountered.