Environmental Site Assessment, Characterization, and Modeling


A significant component of managing environmental liability involves understanding environmental conditions through environmental assessments. Whether impacts are suspected in site soil, groundwater, surface water, sediment, indoor air, or soil vapor, Trihydro has a broad range of experience to assist with the characterization of industrial and abandoned properties with legacy environmental issues.

Site assessments can present multiple challenges, including limited site access, business interruption, and challenging locations. Our approach to site assessments is to gather the most comprehensive data with the least impact on the owner and the property. We focus on quickly obtaining quality investigation data allowing for adequate delineation of impacts, as well as the potential for human or ecological receptor risk. Our project teams have worked in extreme temperature and remote locations, spanning from Puerto Rico to the Rocky Mountains and from California to the unpopulated islands in Alaska. Consequently we are able to complete assessment work and adapt our field methods to keep our professionals safe. With offices nationwide, we also have experience working in urban areas.

Trihydro provides environmental assessment services to its clients in industry and government regardless of project size, from simple ASTM Phase I Environmental Site Assessments (ESAs) to large investigations requiring hundreds of sampling points. We work as an extension of our clients’ staff to identify environmental liabilities that affect financial reserve estimates, document the end-state vision, and reach closure of the environmental matters. Our professionals supplement standard analytical sampling data sets with data from advanced characterization tools such as MIP and UVOST to develop conceptual site models (CSMs). A solid and defensible CSM enables clients to make sound financial decisions regarding the pathway to closure, whether through targeted remediation, a human health and/or ecological risk assessment, or long-term site monitoring. To effectively communicate the CSM for a site, Trihydro uses an integrated strategy to transform standard GIS-based assessment data into a 3-D model of geologic stratigraphy as well as soil and groundwater concentration data. Through this process, we have identified primary contaminant fate and transport pathways for potential migration, which is critical to determining whether the risk of offsite groundwater requires remediation, and whether vapor intrusion into nearby enclosed spaces requires indoor air or soil gas assessments and potentially vapor mitigation.

Field sampling


Trihydro conducts field sampling to collect valuable information to support conceptual site model development and assist with remedial decision-making. Our field professionals support multi-media assessment activities, including air, water, sediment, waste, and soil sampling. Techniques for field sampling are diverse and follow federal and state-approved methodologies. To ensure sample quality and obtain an accurate representation of environmental conditions, field technicians follow strict procedures and develop site-specific sampling and analysis plans. For various industries, field sampling may determine if or how a project moves forward or may assist organizations in complying with environmental regulations.

Chemical Data Evaluation and Analysis


Site owners and operators routinely use analytical chemistry data to make decisions during site investigations, remediation, routine monitoring, and closure. To support effective decision-making and regulatory compliance, organizations rely on accurate and defensible data. Access to reliable data provides actionable insight into the constituents of concern in matrices involved in environmental investigations. This provides site owners and operators the tools to answer various site-related questions that they may be navigating as part of project work or operations. Data evaluation and analysis cover a broad spectrum of activities, including data gap analyses, data usability assessments, data visualization, statistical analyses, and data screening.



During site assessment and characterization activities, modeling produces meaningful results while balancing a hydrologic system's circumstances with project objectives. Models offer a way to develop and organize information so environmental considerations can be viewed and understood holistically. Modeling outputs can help site owners and operators evaluate complex groundwater flow regimes, contaminant fate and transport, and water resource/groundwater supply.

Vapor Intrusion

Vapor intrusion occurs when there is a migration of vapor-forming chemicals from any subsurface contaminant source into an overlying building. Vapor intrusion can lead to indoor air quality concerns and introduce contaminants of concern, such as volatile organic compounds (VOCs), into an indoor environment. Vapor intrusion can represent an immediate pathway for human health concerns due to inhalation. As of December 2018, 42 states have issued draft or final vapor intrusion guidance documents. Individual state regulatory agencies may also oversee assessment and remediation/mitigation of sites affected by vapor intrusion.


Site Characterization and Remediation
Helena, Montana

In 2017, Trihydro began environmental work at a facility with petroleum contamination. Investigations identified areas for active remediation, facilitated the closure of four documented releases, and prioritized remaining areas for remediation.

Solvent Recycling Facility Corrective and Remedial Actions

Trihydro conducted an environmental site assessment and identified chlorinated solvent contamination in the soil and groundwater at a former solvent recycling facility. To address this issue, Trihydro is implementing a comprehensive cleanup plan that utilizes a combination of advanced techniques like dual-phase extraction, bioremediation, and phytoremediation.
Trihydro was easy to work with, paid strict attention to detail, and went above and beyond working with my state's Department of Environmental Protection (DEP) to ensure an easy transition while conforming to the DEP's strict guidelines. They were pleasant, accommodating to my schedules, and they were competitive in their pricing as well. – Ann Albro, Print Shop Manager, Lincoln News

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