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September 19, 2024
Katie Payne
Environmental assessment and remediation programs can often include a sediment characterization component aimed at evaluating potential impacts on ecological and human health risk. The specific approach, goals, and data objectives can vary greatly depending on the type and purpose of the site evaluation, ranging from dredge material disposal, risk assessments for environmental and public health, habitat improvements, remedial goals, construction projects, and more. Analysis of samples in sediment, elutriate, and organism tissue provides information for understanding the presence and potential impact of different types of environmental contaminants. Read on to learn more about each of these matrices.
Sediments can be a source or sink for contaminants of concern (COCs) over time and give us clues about current and historical trends. Chemical analysis of solid-phase or bulk sediment evaluates the presence and quantity of contaminants, which when paired with biological (toxicity) testing, translates direct effects of these COCs to organisms. Different contaminants have different binding affinities for sediment particles, which impacts their bioavailability to organisms living in the sediment. Physical sediment properties (such as grain size, organic content, etc.), can also influence contaminant binding and accessibility. Depending on the ultimate goal of the project, it can be advantageous to pair chemical analysis with biological testing
Elutriates or leachates are created from a mixture of solid-phase sediment and water. They can reveal the partitioning characteristics of COCs (i.e., how likely the COCs are to move into the aqueous fraction) and how organisms living in the water column are affected by water-soluble contaminants that migrate out of the sediment and impact water quality during activities like dredging or disposal.
Elutriate testing provides an estimation of the portion of contaminants that may become mobile and bioavailable. Partitioning can also be explored in leaching and flux studies, and we encourage you to contact us to learn more about what method is most suitable for your project and goals. Results observed can depend on the variables inherent to the elutriate preparation method used, such as mixing intensity and duration as well as ratio of sediment to water.
Tissue testing allows us to assess how contaminants may bioaccumulate in organisms over longer periods of time and be transferred through different tropic levels of the food web. Accumulation of the contaminant levels present in tissues can depend on the choice of species, type of organ tissue (e.g., liver, muscle, blood, or fat), and organism age, diet, and overall health. Tissue exposures can take place in-vivo, in-situ, or can be assessed as part of an ambient fish or animal tissue survey.
With environmental testing for sediment, elutriate, and tissue matrices, here are a few best practices to keep in mind for achieving reliable results:
While it can be a complex undertaking, environmental analysis in sediment, elutriate, and tissue matrices contributes to a comprehensive assessment of COC loads, bioavailability, and ultimately, human health and ecological risk. Understanding the nuances of each matrix and method informs decisions for environmental management, remediation, and protection of public health.
Business Development Manager & Toxicology Testing Expert
Katie Payne is an environmental scientist who has a passion for applying toxicology, biology, and ecology to understand, navigate, and solve complex environmental issues. She has more than 15 years of experience in aquatic toxicity and bioassay at Enthalpy Analytical in San Diego, California. During her career in environmental laboratory services, she’s held positions in bench testing, project management, quality assurance, operations, and business development. She is well versed in conducting routine and specialized freshwater, marine, and sediment toxicity tests in an accredited laboratory setting and utilizing a variety of organisms. She shares her expertise with several collaborative working groups, including The NELAC Institute Whole Effluent Toxicity Testing Expert Committee, the Society of Environmental Toxicology and Chemistry, the California Society of Environmental Analysts, and the Professional Environmental Management Association. Katie has a bachelor’s degree in biology and economics from the University of San Diego and a master’s degree in public health from the University of California, Los Angeles.
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