Environmental Toxicology Laboratory

Environmental Toxicology Laboratory

Facilities and Capabilities

The fully staffed, state-of-the-art laboratory is equipped to conduct rigorous toxicity tests involving freshwater, marine, and terrestrial organisms. Research staff scientists with expertise in ecotoxicology, genomics, ecology, risk assessment, physiology, physical chemistry, biochemistry, and hydrology are available for consultation and collaboration.

The ETL maintains robust cultures of aquatic species, including water fleas (Ceriodaphnia dubia, Daphnia magna), amphipods (Hyalella azteca), midges (Chironomus tentans), fish species (medaka, zebrafish), and terrestrial organisms such as earthworms. The lab obtains other test organisms from commercial suppliers as needed. Laboratories feature advanced water purification systems, environmentally controlled chambers, water baths, animal culture areas, and comprehensive capabilities for analyzing water quality parameters like conductance, hardness, alkalinity, pH, total and residual chlorine, and nutrients.

The adjacent 8,000-square-foot Aquatic Ecology Laboratory provides controlled artificial stream environments, enabling realistic simulation of aquatic ecosystems. This facility is instrumental in studying contaminant behaviors, impacts on biodiversity, nutrient cycling, and overall ecological health. The laboratory houses extensive areas for fish and macroinvertebrate culture and processing, as well as a set of indoor artificial streams served by temperature-controlled filtered stream water, dechlorinated process water, and well-water. The streams, which have been used for projects sponsored by the National Science Foundation and DOE, contain eight replicate channels and allow control over key environmental factors such as discharge, light exposure, and water temperature. In addition to these features, field sampling equipment, boats, and a vehicle fleet are available.

Research and Applications

The lab’s ambient water-quality monitoring employs sophisticated statistical methods to discern relationships between contaminants and aquatic ecosystem integrity. Scientists at ETL have developed innovative bioassay techniques specifically designed for addressing complex environmental challenges, including pioneering methods for assessing groundwater contamination, creating rapid toxicity tests for synthetic fuels, using earthworm soil tests to effectively evaluate risks from land contamination, and employing midges and plant assays to gauge sediment toxicity and overall ecosystem health. The ETL has been recognized for excellence in effluent testing, supporting compliance with environmental regulations through acute and chronic toxicity evaluations of industrial discharges. Notable research achievements include:

Development of Test Methods:

• Groundwater Toxicity Testing: Highly-modified Ceriodaphnia methods assess toxicity of groundwater contaminated with volatile and semivolatile pollutants.
• Particulate Matter Quality Assessment: Near-conventional Ceriodaphnia tests evaluate biological quality of particulate matter from settling basins near Oak Ridge Y-12 Plant.
• Fathead Minnow Survival Analysis: Modified 7-day tests diagnose unusual variations in fathead minnow survival rates.
• Synthetic Fuel Toxicity Screening: Rapid algal-photosynthesis tests efficiently generate dose-response data for synthetic fuel constituents.
• Soil Contamination Assessment: Earthworm survival, growth, and reproduction tests measure soil pollutants.
• Sediment Toxicity Evaluation: Aquatic midge (Chironomus tentans) assays estimate ecological risks from sediment contaminants.
• Ecological Risk Assessment Support: Combined seed-germination and earthworm tests inform assessments at the Portsmouth Gaseous Diffusion Plant and Bear Creek Valley.
• Rapid Snail-Feeding Bioassay: 3-day tests utilize food consumption rates to quickly assess toxicity.
• Multi-Species Mesocosm Tests: Used for comprehensive ecological risk assessments, providing detailed evidence for complex scenarios.
• Advanced Hazard Detection: Development of DNA microarray and genetically modified organism methods for detecting waterborne hazards.

Effluent Testing:

• Compliance Monitoring: EPA-approved acute and chronic tests (Ceriodaphnia dubia, Daphnia magna, fathead minnow larvae) ensure compliance with National Pollutant Discharge Elimination System permits.
• Wastewater Characterization: Detailed toxicity characterization of untreated wastewater, cooling tower blow-down, and chemically complex effluents from specialty treatment systems.

Ambient Water-Quality Testing:

• Biological Quality Monitoring: 7-day static-renewal tests with Ceriodaphnia and fathead minnow larvae pioneered to assess receiving stream quality.
• Extended Monitoring Programs: Extensive ambient testing involving 45 sites across nine streams over 15 years.
• Innovative Statistical Techniques: Development and use of new statistical methods linking physico-chemical water conditions to observed toxicity.
• Embryo-Based Procedures: Fish embryo tests developed and utilized to enhance ambient water quality assessments.

Toxicity Identification and Collaboration

The laboratory possesses extensive expertise in Toxicity Identification and Reduction Evaluations (TI/REs), definitively identifying significant toxicants such as depleted uranium, nickel, zinc, lithium, chlorine, organic dyes, copper, sodium sulfate, and calcium. This expertise supports multiple DOE facilities and federal agencies, including the U.S. Army, Navy, and Tennessee Valley Authority.