Aquatic toxicology databases

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Toxicological databases are large compilations of data derived from aquatic and environmental toxicity studies. Data is aggregated from a large number of individual studies in which toxic effects upon aquatic and terrestrial organisms have been determined for different chemicals. These databases are then used by toxicologists, chemists, regulatory agencies and scientists to investigate and predict the likelihood that an organic or inorganic chemical will cause an adverse effect (i.e. toxicity) on exposed organisms.

Contents

Several such databases have been compiled relating specifically to aquatic toxicology.

Utility

These databases are invaluable resources in the field of aquatic toxicology because the likelihood that a chemical will cause toxicity is highly variable across the broad spectrum of contaminants in the environment. This is because the likelihood of adverse effects on an organism is dependent on the concentration of that substance in the target tissues of the organism, the physicochemical properties of that chemical and the duration of exposure to the chemical. [1] Tools capable of predicting the toxicity of specific chemicals to particular organisms or groups of organisms are essential to regulators and researchers in the field of toxicology.[ citation needed ]

Available databases

In aquatic toxicology multiple databases exist and each generally pertains to a single aspect of aquatic toxicology such as PCBs, [2] tissue residues or sediment toxicity. [3] Other informational and regulatory databases on toxicology in general are maintained by the U.S. EPA, USGS, United States Army Corps of Engineers and the National Oceanic and Atmospheric Administration. In the U.S. there are three major databases pertaining specifically to aquatic toxicology: the Toxicity/Residue Database, the Environmental Residue Effects Database and the ECOTOX database.[ citation needed ]

Toxicity/Residue Database

The Toxicity/Residue Database is maintained by the U.S. EPA and is a database for the prediction of toxicity of organic and inorganic chemicals to aquatic organisms. This data base was developed by the EPA Duluth office and became operational in 1999. [4] The data base is derived from more than 500 peer-reviewed references and is a collection of their findings on roughly 200 chemicals and 190 species both marine and fresh water. Data regarding organism response endpoints or effects are measured as the concentration of chemical in the tissue of the test organism at the time which effects such as lethality, metabolic depression, or increased respiration occur. More than 3,000 effects may be queried from a small piece of downloaded software to gather survival, growth or reproductive endpoint effect data.[ citation needed ]

Environmental Residue Effects Database

The Environmental Residue Effects Database (ERED) is a database maintained by the U.S. Army Corps of Engineers that pairs data regarding the bioaccumulation of toxicants in tissue (via tissue residue) to endpoint effects such as mortality, growth, or physiological and biochemical responses. Response data also include low effect detected (LOED) and no effect detected (NOED) concentrations. This database is derived from 2329 peer-reviewed references regarding 413 chemicals. The database covers literature from 1964 to the present and includes more than 15,000 records. This database is updated with 300 or more records every year on average. The ERED database is specific to sediment toxicity and the effects of contaminates in dredged materials on freshwater organisms. It is intended to be used in evaluating the potential for contaminate concentrations of dredged sediment to have unacceptable adverse effects on aquatic organisms. [5] Although the ERED database was designed as a tool for the Army Corps of Engineers to manage adverse effects of dredging, it is widely applicable to sediment toxicity studies and management.[ citation needed ]

The ECOTOX database

ECOTOX is considered to be more comprehensive in that it holds results from toxicity tests of single chemicals on aquatic and terrestrial plants and animals. Data can be found on both freshwater and marine taxa. ECOTOX collects data from previously EPA established databases AQUIRE, TERRATOX, and PHYTOTOX which individually provide aquatic, terrestrial species and plant data respectively. Data large is collected from peer-reviewed literature however some amount of data is sourced from grey literature. Using the Quick Database Query function enables searches by chemical, taxonomic name, effect, and publication year. Data from ECOTOX is used to provide reference parameters to current toxicity studies and serves as a regulatory guideline.[ citation needed ]

ECOTOX source data screening

Data resulting from toxicity studies that is integrated in to the ECOTOX database is subjected to a screening and quality assurance criteria developed by the EPA and the Office of Pesticide Programs (OPP). In order for study results to be accepted by the EPA and OPP the toxicity study must follow or consist of the following: [6]

  • The toxic effects are related to single chemical exposure;
  • The toxic effects are on an aquatic or terrestrial plant or animal species;
  • There is a biological effect on live, whole organisms;
  • A concurrent environmental chemical concentration/dose or application rate is reported; and
  • There is an explicit duration of exposure.

In addition to the criteria listed above, the following criteria, which are discussed in further detail in Attachment I, are applied by OPP as a further screen of acceptability:

  • Toxicology information is reported for a chemical of concern to OPP;
  • The article is published in the English language;
  • The study is presented as a full article;
  • The paper is a publicly available document;
  • The paper is the primary source of the data
  • A calculated endpoint is reported;
  • Treatment(s) are compared to an acceptable control;
  • The location of the study (e.g., laboratory vs. field) is reported; and
  • The tested species is reported and verified.

Regulatory applications

In the United States, the ECOTOX, ERED (sediment) and Toxicity Residue Databases are used by many regulatory agencies such as state environmental quality agencies and the EPA to determine regulatory environmental toxicant concentration levels. Under the Clean Water Act the EPA has used the ECOTOX database among other information to set wastewater toxicant concentration standards for industry as well as water quality standards for all contaminants in surface waters. Under the CWA, individual states must regulate water quality criteria at or below the concentrations set forth by the EPA. Sediment toxicant concentrations, however, are generally not regulated in the same way. [7] The determination of sediment quality criteria and sediment toxicity testing is highly complex and is often regulated by states or some state run environmental agency. Sediment toxicity evaluations of contaminated sediments are very site specific and toxicant effect levels are often much more variable than those of surface waters. For this reason it may be nearly impossible to develop feasible acceptable sediment concentration regulations that apply to all aquatic systems or regions. [1]

Acceptable concentrations or sediment quality guidelines have been developed and are used in risk assessments and the management of dredged materials. "Sediment quality guidelines" (SQGs), as defined at the 2002 Society of Environmental Toxicology and Chemistry (SETAC) Pellston Workshop, are numerical chemical concentrations intended to be either protective of biological resources, or predictive of adverse effects to those resources, or both. SQGs for assessing sediment quality relative to the potential for adverse effects on sediment-dwelling organisms have been derived using both mechanistic and empirical approaches. [8]

Related Research Articles

<span class="mw-page-title-main">Toxicity</span> Degree of harmfulness of substances

Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell (cytotoxicity) or an organ such as the liver (hepatotoxicity). Sometimes the word is more or less synonymous with poisoning in everyday usage.

Chronic toxicity, the development of adverse effects as a result of long term exposure to a contaminant or other stressor, is an important aspect of aquatic toxicology. Adverse effects associated with Chronic toxicity can be directly lethal but are more commonly sublethal, including changes in growth, reproduction, or behavior. Chronic toxicity is in contrast to acute toxicity, which occurs over a shorter period of time to higher concentrations. Various toxicity tests can be performed to assess the Chronic toxicity of different contaminants, and usually last at least 10% of an organism's lifespan. Results of aquatic Chronic toxicity tests can be used to determine water quality guidelines and regulations for protection of aquatic organisms.

<span class="mw-page-title-main">Aquatic toxicology</span> Study of manufactured products on aquatic organisms

Aquatic toxicology is the study of the effects of manufactured chemicals and other anthropogenic and natural materials and activities on aquatic organisms at various levels of organization, from subcellular through individual organisms to communities and ecosystems. Aquatic toxicology is a multidisciplinary field which integrates toxicology, aquatic ecology and aquatic chemistry.

<span class="mw-page-title-main">Ecotoxicology</span>

Ecotoxicology is the study of the effects of toxic chemicals on biological organisms, especially at the population, community, ecosystem, and biosphere levels. Ecotoxicology is a multidisciplinary field, which integrates toxicology and ecology.

<span class="mw-page-title-main">Ecotoxicity</span>

Ecotoxicity, the subject of study in the field of ecotoxicology, refers to the biological, chemical or physical stressors that affect ecosystems. Such stressors could occur in the natural environment at densities, concentrations, or levels high enough to disrupt natural biochemical and physiological behavior and interactions. This ultimately affects all living organisms that comprise an ecosystem.

<span class="mw-page-title-main">Environmental toxicology</span>

Environmental toxicology is a multidisciplinary field of science concerned with the study of the harmful effects of various chemical, biological and physical agents on living organisms. Ecotoxicology is a subdiscipline of environmental toxicology concerned with studying the harmful effects of toxicants at the population and ecosystem levels.

Toxic equivalency factor (TEF) expresses the toxicity of dioxins, furans and PCBs in terms of the most toxic form of dioxin, 2,3,7,8-TCDD. The toxicity of the individual congeners may vary by orders of magnitude.

In environmental toxicology, effects range low (ERL) and effects range median (ERM) are measures of toxicity in marine sediment. They are used by public agencies in the United States in formulating guidelines in assessing toxicity hazards, in particular from trace metals or organic contaminants.

The Biotic Ligand Model (BLM) is a tool used in aquatic toxicology that examines the bioavailability of metals in the aquatic environment and the affinity of these metals to accumulate on gill surfaces of organisms. BLM depends on the site-specific water quality including such parameters as pH, hardness, and dissolved organic carbon. In this model, lethal accumulation values are used to be predictive of lethal concentration values that are more universal for aquatic toxicology and the development of standards. Collection of water chemistry parameters for a given site, incorporation of the data into the BLM computer model and analysis of the output data is used to accomplish BLM analysis. Comparison of these values derived from the model, have repeatedly been found to be comparable to the results of lethal tissue concentrations from acute toxicity tests. The BLM was developed from the gill surface interaction model (GSIM) and the free ion activity model (FIAM). Both of these models also address how metals interact with organisms and aquatic environments. Currently, the United States Environmental Protection Agency (EPA) uses the BLM as a tool to outline Ambient Water Quality Criteria (AWQC) for surface water. Because BLM is so useful for investigation of metals in surface water, there are developmental plans to expand BLM for use in marine and estuarine environments.

A mode of toxic action is a common set of physiological and behavioral signs that characterize a type of adverse biological response. A mode of action should not be confused with mechanism of action, which refer to the biochemical processes underlying a given mode of action. Modes of toxic action are important, widely used tools in ecotoxicology and aquatic toxicology because they classify toxicants or pollutants according to their type of toxic action. There are two major types of modes of toxic action: non-specific acting toxicants and specific acting toxicants. Non-specific acting toxicants are those that produce narcosis, while specific acting toxicants are those that are non-narcotic and that produce a specific action at a specific target site.

Fish acute toxicity syndrome (FATS) is a set of common chemical and functional responses in fish resulting from a short-term, acute exposure to a lethal concentration of a toxicant, a chemical or material that can produce an unfavorable effect in a living organism. By definition, modes of action are characterized by FATS because the combination of common responses that represent each fish acute toxicity syndrome characterize an adverse biological effect. Therefore, toxicants that have the same mode of action elicit similar sets of responses in the organism and can be classified by the same fish acute toxicity syndrome.

Tissue residue is the concentration of a chemical or compound in an organism's tissue or in a portion of an organism's tissue. Tissue residue is used in aquatic toxicology to help determine the fate of chemicals in aquatic systems, bioaccumulation of a substance, or bioavailability of a substance, account for multiple routes of exposure, and address an organism's exposure to chemical mixtures. A tissue residue approach to toxicity testing is considered a more direct and less variable measure of chemical exposure and is less dependent on external environmental factors than measuring the concentration of a chemical in the exposure media.

Toxicodynamics, termed pharmacodynamics in pharmacology, describes the dynamic interactions of a toxicant with a biological target and its biological effects. A biological target, also known as the site of action, can be binding proteins, ion channels, DNA, or a variety of other receptors. When a toxicant enters an organism, it can interact with these receptors and produce structural or functional alterations. The mechanism of action of the toxicant, as determined by a toxicant’s chemical properties, will determine what receptors are targeted and the overall toxic effect at the cellular level and organismal level.

The maximum acceptable toxicant concentration (MATC) is a value that is calculated through aquatic toxicity tests to help set water quality regulations for the protection of aquatic life. Using the results of a partial life-cycle chronic toxicity test, the MATC is reported as the geometric mean between the No Observed Effect Concentration (NOEC) and the lowest observed effect concentration (LOEC).

An early life stage (ELS) test is a chronic toxicity test using sensitive early life stages like embryos or larvae to predict the effects of toxicants on organisms. ELS tests were developed to be quicker and more cost-efficient than full life-cycle tests, taking on average 1–5 months to complete compared to 6–12 months for a life-cycle test. They are commonly used in aquatic toxicology, particularly with fish. Growth and survival are the typically measured endpoints, for which a Maximum Acceptable Toxicant Concentration (MATC) can be estimated. ELS tests allow for the testing of fish species that otherwise could not be studied due to length of life, spawning requirements, or size. ELS tests are used as part of environmental risk assessments by regulatory agencies including the U.S. Environmental Protection Agency (EPA) and Environment Canada, as well as the Organisation for Economic Co-operation and Development (OECD).

Simultaneously extracted metals/Acid-volatile sulfide (SEM-AVS) is an approach used in the field of aquatic toxicology to assess the potential for metal ions found in sediment to cause toxic effects in organisms dwelling in the sediment. In this approach, the amounts of several heavy metals in a sediment sample are measured in a laboratory; at the same time, the amount of acid-volatile sulfide is determined. Based on the chemical interactions between heavy metals (SEM) and acid-volatile sulfide (AVS), the concentrations of these two components can be used to assess the potential for toxicity to sediment-dwelling organisms.

Equilibrium partitioning Sediment Benchmarks (ESBs) are a type of Sediment Quality Guideline (SQG) derived by the US Environmental Protection Agency (EPA) for the protection of benthic organisms. ESBs are based on the bioavailable concentration of contaminants in sediments rather than the dry-weight concentration. It has been demonstrated that sediment concentrations on a dry-weight basis often do not predict biological effects. Interstitial water concentrations, however, predict biological effects much better. This is true because the chemical present in the interstitial water (or pore water) is the uncomplexed/free phase of the chemical that is bioavailable and toxic to benthic organisms. Other phases of the chemical are bound to sediment particles like organic carbon (OC) or acid volatile sulfides (AVS) and are not bioavailable. Thus the interstitial water concentration is important to consider for effects to benthic organisms.

In aquatic toxicology, the sediment quality triad (SQT) approach has been used as an assessment tool to evaluate the extent of sediment degradation resulting from contaminants released due to human activity present in aquatic environments. This evaluation focuses on three main components: 1.) sediment chemistry, 2.) sediment toxicity tests using aquatic organisms, and 3.) the field effects on the benthic organisms. Often used in risk assessment, the combination of three lines of evidence can lead to a comprehensive understanding of the possible effects to the aquatic community. Although the SQT approach does not provide a cause-and-effect relationship linking concentrations of individual chemicals to adverse biological effects, it does provide an assessment of sediment quality commonly used to explain sediment characteristics quantitatively. The information provided by each portion of the SQT is unique and complementary, and the combination of these portions is necessary because no single characteristic provides comprehensive information regarding a specific site

The acute to chronic ratio (ACR) uses acute toxicity data to gauge the chronic toxicity (MATC) of a chemical of interest to an organism. The science behind determining a safe concentration to the environment is imperfect, statistically limited, and resource intensive. There is an unfilled demand for the rapid assessment of different chemical toxicity to many different organisms. The ACR is a proposed solution to this demand.

Toxic units (TU) are used in the field of toxicology to quantify the interactions of toxicants in binary mixtures of chemicals. A toxic unit for a given compound is based on the concentration at which there is a 50% effect for a certain biological endpoint. One toxic unit is equal to the EC50 for a given endpoint for a specific biological effect over a given amount of time. Toxic units allow for the comparison of the individual toxicities of a binary mixture to the combined toxicity. This allows researchers to categorize mixtures as additive, synergistic or antagonistic. Synergism and antagonism are defined by mixtures that are more or less toxic than predicted by the sum of their toxic units.

References

  1. 1 2 Rand, Gary M. (1995). Fundamentals of aquatic toxicology: effects, environmental fate and risk assessment (3rd ed.). CRC Press. ISBN   9781560320906 . Retrieved 18 May 2016.
  2. ↑ "PCBRes (PCB Residue Effects) - Research - US EPA". archive.epa.gov.
  3. ↑ Bay, Steven. "Spiked Sediment Database". Society of Environmental Toxicology and Chemistry Sediment Advisory Group. Retrieved 18 May 2016.
  4. ↑ Elonen, Colleen. "Toxicity Residue Research". U.S. Environmental Protection Agency.
  5. ↑ Bridges, Todd (1999). "Interpreting Bioaccumulation Data with the Environmental Residue-Effects Database". Technical Notes Collection. Archived from the original on August 5, 2016. Retrieved 18 May 2016.
  6. ↑ "Evaluation Guidelines for Ecological Toxicity Data in the Open Literature". United States Environmental Protection Agency. EPA. 15 July 2015. Retrieved 24 May 2016.
  7. ↑ Chapman, PM (1989). "Current approaches to developing sediment quality criteria". Environmental Toxicology and Chemistry. 8 (7): 589–599. doi: 10.1002/etc.5620080706 .
  8. ↑ "Use of Sediment Quality Guidelines and Related Tools for the Assessment of Contaminated Sediments", Executive Summary Booklet of a SETAC Pellston Workshop, SETAC, 2002.
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