Site & Risk Assessment



Site Assessment

Northstar has extensive experience performing site assessments and remedial investigations in a variety of many different geological settings and pertaining to a wide range of soil and groundwater contaminants. Northstar has experience working in inter-tidal, marine, estuary, lacustrine, hard-rock, fractured bedrock settings, and with artesian, confined and unconfined aquifer conditions to depths extending to 1,000 feet below ground surface. The company has in-depth experience using numerous investigative technologies to obtain the required project data needs. These include hand auguring; soil-gas (vapor) indoor air/ambient air sampling; direct-push; hydropunch/isoflow/flute/packer-assembly sampling; drilling (hollow-stem auger/ rotosonic/direct-mud/reverse-mud circulation/dual-wall percussion/bucket auger/OdexTM/wire-line/vibracore, etc.).

Northstar can perform aquifer assessment and analysis including (step-test, constant-rate, and hydrophysics), vertical, slant, and horizontal well installation, downhole and surface geophysical surveys etc.

Depend on Northstar to assess your site for any soil or groundwater contaminants including heavy metals, chlorinated solvents, petroleum-fuel hydrocarbons, pesticides (including herbicides), PCBs and PAHs, radionuclides, nerve gas agents and unexploded ordinances. All of these contaminants and more have been investigated by our staff at military installations, industrial facilities, public and private utility operations, and large and small commercial and retail properties.

Project Management Services

No project can be properly completed without expert management. Northstar's professional management services include project planning and management, regulatory agency and stakeholder consultation, workplan preparation and submittal, permitting, procurement and scheduling of staff and subcontractors, implementation of field programs, waste management including profiling, appropriate storage, transport, and disposal. Northstar's projects are designed and conducted by registered and certified professional staff who directly oversee and are commonly in the field managing the project(s), collecting required data, and ensuring that all project requirements are met. Our staff includes those possessing MBA degrees combined with "real world" direct experience in environmental consulting and project management. Who better to trust your project to than a team who has been there, done that, and has the education and experience to back up their work?

Risk Assessment

Indoor air, soil-gas, and soil and aquifer contaminant modeling and risk assessments can be conducted at sites to establish the cleanup levels for a site in consideration of its present and future uses. If risk assessment is conducted at the conclusion of site characterization, then the cleanup goals are known when selecting a remediation method and the method can be evaluated in regards to its effectiveness to achieve those levels. Risk assessment can also be performed at the conclusion of remediation activities to determine whether contaminants left in place pose a threat to human health or the environment. Most remediation methods cannot effectively remove all contaminants but site owners can achieve closure if it can be demonstrated that human health and sensitive receptors are not impacted by the remaining residual impacts.

Risk assessment for site closure is used in conjunction with modeling to demonstrate that remediation is effective, that steady state conditions exist, and that remaining contaminant concentrations at the site do not pose a threat to sensitive receptors. The closure process generally includes a site closure review, report of all site data, historic sampling data, and the compilation of remediation data along with the results of confirmation sampling. It may also include collection of indoor air samples and other sampling to ensure that migration of contaminants is not occurring. Northstar typically submits this report to the local agency responsible for site closure. At times, it is a negotiated process of working through agency concerns and tempering agency requests with discussion as to the feasibility and economic value of further work. Once resolved, Northstar will request site closure. If the agency approves, Northstar will issue a Case Closure Summary for the agency to review. The agency will issue a No Further Action letter granting closure status for the site.

Indoor Air Risk Assessment

Northstar monitors indoor air quality to protect the health of workers in structures built over impacted sites. The results of indoor air sampling events can be modeled to determine whether contaminant concentrations fall within an acceptable range for human occupation. If not, Northstar works with customers to engineer the work space to protect workers and reduce the liability resulting from contaminant migration. Northstar's professionals are adept at a variety of risk assessment strategies and models to accommodate a range of contaminants and conditions.