Activities
The ATL focuses on research activities that measure the adverse impacts of chemical and physical stressors on aquatic organisms, and that identify dominant stressors. Many chemical and physical stressors affect the health of aquatic ecosystems. The sources of chemical contamination in California surface waters come from a variety of land use practices including industrial effluents, mining, dairy production, agriculture, and NPDES point source discharges. Physical stressors include habitat degradation, including high salinity, high temperature, oxygen depletion and excess sedimentation. In many instances, multiple stressors are present simultaneously.
No individual research method can simultaneously determine the effects of chemical and physical stressors on the aquatic communities. Therefore, the ATL utilizes several water quality assessment tools that complement one another to address specific research objectives. In addition, biomarker tools are now available to detect the sublethal effects of toxic contaminants. These tools, when combined, provide more “weight of evidence” to evaluate the health of aquatic ecosystems.
Our Commitment
For each project, the ATL is committed to producing quality results including strategic sampling plans, carefully executed research procedures, thorough statistical analyses and interpretive reports.
Aquatic Toxicity Testing Capabilities
Sediment Toxicity Testing Capabilities
Biomarker Analyses
Field Capabilities
Undergraduate and Graduate Learning Opportunities
Aquatic Toxicity Testing Capabilities
- 96-hour Selenastrum capricornutum (green algae) growth test
- 96-hour Ceriodaphnia dubia (waterflea) survival test
- 96-hour Pimephales promelas (fathead minnow) survival test
- 96-hour Oncorhynchus mykiss (rainbow trout) survival test
- 7-day Ceriodaphnia dubia reproduction and survival test
- 7-day Pimephales promelas larval biomass and survival test
- 10-day Hyalella azteca (amphipod) growth and survival test
The ATL is certified by the California Department of Health Services to conduct standard EPA freshwater toxicity testing methods. These test methods are a cost effective mean to evaluate the extent, frequency, duration and magnitude of toxicity in inland surface waters. In these tests, surrogate species are used to represent various levels in the food chain. The protocols for these species (with the exception of H. azteca) are described in US EPA’s Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms, Third Edition (1994) and Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, (1993). The ATL conducts the following tests:
- Toxicity Identification Evaluations (TIEs)
Used in conjunction with chemical analyses, TIEs are a series of procedures designed to identify the chemical cause of toxicity. TIEs are typically used with one of the following test species: Ceriodaphnia dubia (waterflea), Pimephales promelas (fathead minnow larvae), Hyalella azteca (amphipod). The ATL has developed and continues to develop TIE methods for additional species to broaden the application of this tool.
- Resident Species Toxicity Tests
Resident species often have different sensitivities to toxic chemicals relative to the standard freshwater species. The ATL has expertise and experience in developing toxicity tests with non-standard aquatic species of interest in the Sacramento-San Joaquin watersheds and estuary, for example, delta smelt, striped bass, resident chironomids and resident water flea species.
- Bioassessment
Bioassessment procedures utilize biological community information, such as macro-invertebrate species diversity and abundance, along with habitat quality assessments to evaluate the integrity and ecological health of a particular water body. These procedures assess the effects habitat degradation, including chemical pollution, temperature and salinity effects and suspended solids enrichment.
Benthic macro-invertebrates, organisms that spend at least part of their life cycle on or in the bottom substrates of freshwater habitats, are most commonly used for stream bioassessment procedures. Due to the invertebrate’s stationary nature, these in-stream indicators integrate the effects of environmental stress over time. The ATL performs professional level sample collection, taxonomic identification and data analysis according to the California Department of Fish and Game California Stream Bioassessment Procedures and the Environmental Protection Agency Multi-Habitat Approach (EPA 841-B-99-002).
Sediment Toxicity Testing Capabilities
- 96-hour Chironomus tentans (midge larvae) survival test
- 96-hour Chironomus riparius (midge larvae) survival test
- 10-day Hyalella azteca (amphipod) growth and survival test.
Chemicals adsorbed to sediments may impair the health of benthic and epibenthic animals, organisms that live in or interact with bottom sediments. The ATL uses sediment toxicity testing methods to evaluate potential impacts sediment-associated toxicants on these species.
- Vitellogenin analysis (m-RNA/protein)
Estrogenic compounds, such as pharmaceuticals and pesticides, may cause sub-lethal reproductive effects on aquatic organisms. Vitellogenin, an egg yolk protein precursor found in the liver, is a well-known biomarker for the disruption of the endocrine system by estrogens and estrogen-mimicks in juvenile and male fish.
- Acetylcholine esterase (AChE) inhibition
Organophosphate and carbamate insecticides inhibit the activity of the enzyme AChE in the nervous system. AChE inhibition is an excellent biomarker for measuring exposure and effect of these chemicals. It is routinely used to monitor humans at risk of OP or carbamate exposure.
- EROD (ethoxyresorufin O-deethylase) activity
EROD activity is greatly enhanced by the presence of polycyclic aromatic hydrocarbons (PAHs), chlorinated hydrocarbons, and polychlorinated biphenyls (PCBs), and is a sensitive indicator of exposure to these chemicals.
- Metallothionein
Metallothionein is a protein that binds to heavy metals. Its main cellular function is to render heavy metals non-toxic, therefore measuring metallothionein concentration in organisms exposed to heavy metals is a good indicator for heavy metal exposure.
- Heat-shock protein (HSP) analysis
Heat-shock proteins are proteins involved in protecting cells and tissues from environmental stressors. They are general stress indicators, and have been shown to be particularly useful in identifying the effects of temperature stress on aquatic organisms.
- Gene expression analysis
When organisms are coping with environmental stressors, they turn on the expression (production) of particular genes to produce proteins and enzymes that break down contaminants and protect cells from damage. Over- or underexpression of specific genes can be indicative of exposure or effect of specific types of contaminants or stressors, thus assisting in identifying stressors of concern. Gene expression analysis can readily be performed on species whose genetic code is relatively well known, such as fathead minnow, rainbow trout, and striped bass. A microarray for delta smelt is under development at ATL.
- Surface water and sediment sampling
ATL’s field crew collects water and sediment samples from a wide array of water bodies according to EPA and/or SWAMP (California Surface Water Ambient Monitoring Program) specifications.
- Water quality monitoring
ATL routinely collects water quality data. Equipment is maintained and calibrated according to EPA and/or SWAMP specifications.
- Bioassessment sample collection
The ATL performs sample collection for bioassessment according to the California Department of Fish and Game California Stream Bioassessment Procedures and the Environmental Protection Agency Multi-Habitat Approach (EPA 841-B-99-002).
- In situ toxicity tests
In their natural environment, aquatic organisms are often exposed to continuously changing chemical concentrations and conditions. Laboratory tests cannot mimic natural exposure scenarios without considerable expense. In situ testing provides information on the cumulative affect of site specific conditions as they change over time.
ATL has successfully developed and applied in situ exposure equipment for fish larvae and macro-invertebrates.
Undergraduate and Graduate Learning Opportunities
In support of the University’s teaching mission, the ATL continually employs several undergraduate and graduate student assistants from various University programs. These students learn and apply many important concepts and procedures within the aquatic toxicology discipline. In addition, the ATL director and staff mentor a number of graduate students and provide space and support for their research activities. For a virtual tour of our laboratory, see the facility page of our website.
