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Environmental Toxicology

school of fish

Abt Global investigates complex toxicological effects of contaminants in the environment.

Our toxicologists design, implement, conduct and manage a wide range of laboratory and field-based bioassays, investigations and other tests to fill key data gaps and increase our understanding of the adverse effects of chemicals and mixtures on numerous organisms, including bacteria, algae, invertebrates, fish, reptiles, birds, and mammals.

We utilize our in-house expertise, as well as our strategic collaborations and partnerships with university, private, federal, and state laboratories, to determine the toxicity of a wide range of contaminants under varying conditions while applying state-of-the-art toxicity metrics. We offer a holistic approach to assessing toxicity that includes a range of endpoints including standard, molecular, physiological, and behavioral metrics aimed at interpreting how contaminants adversely affect plants and animals in the environment.

rocky stream


Our techniques include a range of toxicity testing scenarios, including:

  • Evaluation of the toxicity of major organic and inorganic contaminants (e.g., crude oil and derivatives, metals, PCBs, pesticides, etc.)

  • Standardized toxicity testing according to published protocols

  • Project or site-specific toxicity testing

In addition to theoretical and applied research into the mechanisms and toxic effects of contaminants, we have extensive experience applying our expertise to practical problems such as regulatory standard setting, the development of adverse effects thresholds and response models, extrapolating laboratory observations to the field, expert testimony, ecological risk assessments, and natural resource damage assessments.

oil spill

Relevant Expertise

Deepwater Horizon: Natural Resource Damage Assessment Toxicity Testing Program

  • National Oceanic and Atmospheric Administration (NOAA)

  • US Fish and Wildlife Service (USFWS)

  • State of Louisiana

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The Deepwater Horizon (DWH) oil spill was of national significance, exposing and injuring natural resources in many areas of the northern Gulf of Mexico. As a result, natural resource trustees (e.g., state and federal agencies) initiated a natural resource damage assessment (NRDA). As part of the assessment, Abt assisted with assessing the exposure to contaminants such as oil and dispersant, injuries resulting from that exposure, and compensation (damages) for restoration. Abt also designed, directed, and managed the Trustee’s aquatic toxicity testing program and served as one of the Principal Investigators for this program as well as for the USFWS avian toxicity testing program. These programs have included 30 universities and federal, state and private laboratories conducting research and analysis on the toxicity of oil, dispersant and their effects on 40 different phytoplankton, invertebrate, fish, reptile and bird species. Toxicity test data have been coupled with analytical chemistry data to aid in determining and quantifying injuries to a variety of marine, animal and plant life exposed to oil. We completed over 650 definitive bioassays and chemical characterizations of oil and dispersant in water and sediment. Abt also played a key role in authoring many sections of the DWH Programmatic Damage Assessment and Restoration Plan (PDARP) in close collaboration with NOAA and USFWS and authored several supporting technical appendices.

cityscape of portland, oregon

Sediment Bioassays with Pacific Lamprey Ammocoetes, Portland Harbor, OR

Client: The Portland Harbor Natural Resource Trustee Council

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Abt supported Trustees as part of the Portland Harbor Natural Resource Damage Assessment on many aspects, including the injury assessment. Abt designed, implemented and managed a suite of sediment bioassays on Pacific lampreys, in close collaboration with Oregon State University, the Confederated Tribes of the Siletz Indians, and the US Fish and Wildlife Service. This work included collecting contaminated and reference sediment from the Willamette River, which was used to conduct a series of bioassays examining the effects of various contaminant mixtures on ammocoete survival, growth and behavior. This program also included detailed methods development for conducting work with this unique species/life stage.

map of alaska

Copper Toxicity to Salmonids in the Bristol Bay Watershed, AK

Client: Bristol Bay Heritage Land Trust

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Bristol Bay supports the largest commercial sockeye salmon fishery in the world, and also an important subsistence fishery for native communities. Abt designed and conducted bioassays using two model fish species (rainbow trout and fathead minnows) in close collaboration with Colorado Parks and Wildlife, using site water from the watershed and reconstituted laboratory water with similar properties to conduct a series of tests to evaluate the soundness of existing and alternative water quality criteria (hardness-criteria and Biotic Ligand Model derived criteria). Our research demonstrates that current copper criteria standards used by the state of Alaska and others may not be sufficient to protect salmon in the watershed.

river and riverbank

Photo-Induced Toxicity of North West Shelf Oil, Perth, Western Australia

Collaboration with Australia’s Commonwealth Scientific and Industrial Research Organisation and University of North Texas

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Photo-induced toxicity of crude oil occurs when ultraviolet light (UV) contacts certain photo-active polycyclic aromatic hydrocarbons (PAHs). These PAHs set off chain reactions that cause cell and tissue damage, and results in death and other sublethal effects. There are at least 14 PAHs in crude oil that are known to be photo-active, and our recent work indicates that photo-activation increases toxicity by 10-100 times. In collaboration with Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the University of North Texas, we investigated photo-induced toxicity of crude oil from Australia’s North West Shelf (NWS) on two species of native fish at the Indian Ocean Marine Research Centre in Perth, Australia. Our laboratory tests determined that exposure to NWS oil and UV results in photo-induced toxicity through both photo-sensitization and photo-modification.

underwater goop

Metals Toxicity in Aquatic Environments

Client: Multiple state and federal agencies

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Abt staff have more than 20 years’ experience investigating the toxicity of metals to fish, aquatic invertebrates, birds and other wildlife. This work includes identifying the fate and transport of metals in impacted environments and biogeochemical influences on metal concentrations and diel metal cycling in aquatic environments. Our research also includes laboratory and field assays designed to determine the fate and transport as well as the waterborne and dietary toxicity and associated modes of action of several metals and metalloids associated with mining activities including arsenic, cadmium, cobalt, copper, lead, nickel and zinc. Additionally, we have conducted associated research on the influence of water quality (e.g., anions, cations, alkalinity, pH, and organic carbon) on metal toxicity and evaluated various regulatory guidelines and approaches to assessing toxicity under a range of environmental and chemical conditions.

Contact Us

Jeffrey Morris, Ph.D.

Division of Health and Environment
(303) 381-8231 (O) | (303) 910-2897 (M)

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