Technical Integrity / Collaboration / Exceptional Results

OPTICS: Characterizing Contaminant Transport in Complex Aquatic Environments

Developing conceptual models for contaminated aquatic sites requires a complete picture of contaminant sources and transport mechanisms.  High frequency environmental variability that can result in rapid changes in water quality, such as storm events, tidal fluctuations, and biological perturbations, can be difficult to ascertain using traditional water quality monitoring techniques.  These biophysical processes can substantially affect contaminant movement throughout a site, and make it difficult to understand chemical dynamics under constantly changing environmental conditions.

Integral’s OPTically based In situ Characterization System (OPTICS) overcomes this challenge by using an in situ instrumentation package that supports near-continuous, high-resolution (e.g., hourly or less) estimation of dissolved and particulate contaminant concentrations over extended time periods (e.g., months).

“OPTICS technology makes it possible to track the concentrations of specific chemicals in the water column over time in ways traditional sampling simply cannot,” says Integral principal engineer Todd Martin, P.E., who is using the device to obtain information on critical hydrodynamic and sediment transport processes at a New Jersey Superfund site that encompasses 12 square miles of wetlands.

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The OPTICS platform incorporates a number of physical and water quality measurement probes within its main frame, including probes for chlorophyll a, currents, and water clarity.


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Field measurements using OPTICS demonstrate how chemicals in a contaminated waterway fluctuate over time and correlate with suspended solids in the water column.


The frequency and volume of data obtainable using OPTICS support the development and refinement of conceptual site models and allow for a comprehensive understanding of site water quality and contaminant transport.  When coupled with flow measurements, OPTICS also supports detailed quantification of contaminant mass flux, which is critical to understanding sources of contaminants to the water column.

Autonomous deployment of OPTICS makes it a uniquely powerful and cost-effective tool for environmental managers seeking to gather the data necessary to design and evaluate remedies for complex aquatic sites.


The compact size of the OPTICS unit allows Integral staff to deploy it from small watercraft.

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OPTICS can be used in estuarine, saline, and freshwater environments.

Integral scientists have successfully used OPTICS to evaluate the movement and concentration of chemical contaminants at several contaminated sediment sites.  The data collected allow clients to visualize how specific contaminants move through the water column over time, ultimately supporting the development of effective remedies that protect humans and wildlife from potential chemical exposures.

For more information on OPTICS, contact Todd Martin at or Grace Chang at