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Terms & Acronyms

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Term	Acronym	Vocabulary	Vocabulary Type	Definitions
Acceptable Intake for Chronic Exposure	AIC		Abbreviation and Acronym List
Acceptable Intake for Subchronic Exposure	AIS		Abbreviation and Acronym List
chronic		Thesaurus of Terms Used in Microbial Risk Assessment	Thesaurus	Definition 1: Occurring over a long time (compare with acute). [ATSDR 2004] Definition 2: Occurring over a long period of time, either continuously or intermittently; used to describe ongoing effects that develop only after a long exposure, especially when referring to health. [CRCWQT 2002] Definition 3: Referring to a health-related state, lasting a long time; referring to exposure, prolonged or long-term, often with specific reference to low intensity. [MERREA 2005]
Chronic		Waste and Cleanup Risk Assessment Glossary	Glossary and Key Word List	Definition: Involving a stimulus that is lingering or continues for a long time; often signifies periods from several weeks to years, depending on the reproductive life cycle of the species. Can be used to define either the exposure or the response to an exposure (effect). Chronic exposures typically induce a biological response of relatively slow progress and long duration.
Chronic		Drinking Water Technical & Legal Terms	Glossary and Key Word List	Definition: Occurring over a long period of time, either continuously or intermittently; used to describe ongoing exposures and effects that develop only after a long exposure.
Chronic		National Pollutant Discharge Elimination System (NPDES) Glossary	Glossary and Key Word List	Definition: A stimulus that lingers or continues for a relatively long period of time, often one-tenth of the life span or more. Chronic should be considered a relative term depending on the life span of an organism. The measurement of a chronic effect can be reduced growth, reduced reproduction, etc., in addition to lethality.
Chronic		Urban Watershed Management Research Terminology	Glossary and Key Word List	Definition: A stimulus that lingers or continues for a relatively long period of time, often one-tenth of the life span or more. Chronic should be considered a relative term depending on the life span of an organism. The measurement of a chronic effect can be reduced growth, reduced reproduction, etc., in addition to lethality.
Chronic		Ag 101 Glossary of American Agriculture	Glossary and Key Word List	Definition: Used to describe recurring symptoms or disease.
chronic acidification		Acid Rain Glossary	Glossary and Key Word List	Definition: Generally refers to surface waters that remain acidified (ANC<0) regardless of variations in hydrologic conditions (precipitation, stream flow, etc.).
Chronic Daily Intake	CDI		Abbreviation and Acronym List
chronic effect		Environmental Issues Terms & Acronyms	Glossary and Key Word List	Definition: An adverse effect on any living organism in which symptoms develop slowly over a long period of time or recur frequently.
chronic effect		Thesaurus of Terms Used in Microbial Risk Assessment	Thesaurus	Definition 1: An effect which occurs as a result of repeated or long term (chronic) exposures. [EPA 2003] Definition 2: An adverse effect on a human or animal in which symptoms recur frequently or develop slowly over a long period of time. [EPA 2005b] Definition 3: An adverse effect on any living organism in which symptoms develop slowly over a long period of time or recur frequently. [EPA 2005e]
Chronic Effect		Terms of Environment	Glossary and Key Word List	Definition: An adverse effect on a human or animal in which symptoms recur frequently or develop slowly over a long period of time.
Chronic Effect		Pesticides Glossary	Glossary and Key Word List	Definition: An adverse effect on any living organism in which symptoms develop slowly over a long period of time or recur frequently.
Chronic Effect		NPDES Permit Writers Manual Glossary	Glossary and Key Word List	Definition: The effect of a stimulus that lingers or continues for a relatively long period, often one-tenth of the life span or more. The measurement of a chronic effect can be reduced growth, reduced reproduction, and such, in addition to lethality.
Chronic Effect		Integrated Risk Information System (IRIS) Glossary	Glossary and Key Word List	Definition: An effect that occurs as a result of repeated or long term (chronic) exposures.
Chronic Exposure		Integrated Risk Information System (IRIS) Glossary	Glossary and Key Word List	Definition: Repeated exposure by the oral, dermal, or inhalation route for more than approximately 10% of the life span in humans (more than approximately 90 days to 2 years in typically used laboratory animal species).
Chronic Exposure		Terms of Environment	Glossary and Key Word List	Definition: Multiple exposures occurring over an extended period of time or over a significant fraction of an animal's or human's lifetime (Usually seven years to a lifetime.)
Chronic Exposure		Drinking Water Technical & Legal Terms	Glossary and Key Word List	Definition: Long-term, low-level exposure to a toxic chemical.
Chronic exposure		Exposure Factors Handbook: Glossary	Glossary and Key Word List	Definition: Repeated exposure by the oral, dermal, or inhalation route for more than approximately 10% of the life span in humans (more than approximately 90 days to 2 years in typically used laboratory animal species).
Chronic Exposure		RadTown Glossary	Glossary and Key Word List	Definition: Continuous or intermittent exposure to low doses of radiation over a long period of time. There is often a delay between the exposure and any potential health effect.
Chronic Exposure		Radiation Protection Radiation Glossary	Glossary and Key Word List	Definition: Continuous or intermittent exposure to radiation over a long period of time. With chronic exposure, there is a delay between the start of the exposure and the observed health effect, such as cancer, benign tumors, cataracts, and potentially harmful genetic changes.
Chronic Exposure		Superfund for Students and Teachers Glossary	Glossary and Key Word List	Definition: Continuous or repeated exposure to a hazardous substance over a long period of time.
Chronic Exposure		Community-Based Air Pollution Projects Glossary	Glossary and Key Word List	Definition: Multiple exposures occurring over an extended period of time, or a significant fraction of the animal's or the individual's lifetime.
Chronic Exposure		I-BEAM Glossary of Terms	Glossary and Key Word List	Definition: Long-term exposure lasting several weeks to a lifetime.
Chronic Exposure		Web Taxonomy-Health Topics	Taxonomy	Definition: Contact with a substance that occurs over a long time (more than 1 year) [compare with acute exposure] [The Agency for Toxic Substances and Disease Registry (ATSDR)]
chronic exposure		Thesaurus of Terms Used in Microbial Risk Assessment	Thesaurus	Definition 1: Repeated exposure by the oral, dermal, or inhalation route for more than approximately 10% of the life span in humans (more than approximately 90 days to 2 years in typically used laboratory animal species). [EPA 2003] Definition 2: Continuous exposure, or multiple exposures, occurring over an extended period of time or a significant fraction of the animal’s or the individual’s lifetime. [EPA 2004] Definition 3: Multiple exposures occurring over an extended period of time or over a significant fraction of an animal’s or human’s lifetime (usually seven years to a lifetime). [EPA 2005b] Definition 4: Contact with a substance that occurs over a long time (more than one year). [ATSDR 2004] Definition 5: Multiple exposures occurring over an extended period of time, or a significant fraction of the animal’s or the individual’s lifetime. [RAIS 2004] Definition 6: A continuous or intermittent long-term contact between an agent and a target. (Other terms, such as “long-term exposure,” are also used.) [IPCS 2004]
Chronic Exposure		Benchmark Dose Software (BMDS) Glossary of Terms	Glossary and Key Word List	Definition: Long-term exposure usually lasting 6 months to a lifetime.
Chronic Health Effect		Drinking Water Glossary	Glossary and Key Word List	Definition: The possible result of exposure over many years to a drinking water contaminant at levels above its MCL.
chronic health effect		Safe Drinking Water Act Glossary	Glossary and Key Word List	Definition: The possible result of exposure over many years to a drinking water contaminant at levels above its Maximum Contaminant Level.
chronic health effects		Thesaurus of Terms Used in Microbial Risk Assessment	Thesaurus	Definition 1: An effect which occurs as a result of repeated or long term (chronic) exposures. [EPA 2003, EPA 2004] Definition 2: An adverse effect on a human or animal in which symptoms recur frequently or develop slowly over a long period of time. [EPA 2005b] Definition 3: Having a persistent, recurring or long-term nature. [RAIS 2004, SRA 2004]
Chronic Health Hazard		Chemical Emergency Preparedness and Prevention Glossary	Glossary and Key Word List	Definition: Persistent or prolonged injury
Chronic Human Health		Risk-Screening Environmental Indicators (RSEI) Glossary	Glossary and Key Word List	Definition: The RSEI model addresses both chronic effects and chronic exposures related to human health. Chronic effects are those that generally persist over a long period of time whether or not they occur immediately after exposure or are delayed. Chronic exposure refers to multiple exposures occurring over an extended period of time, or a significant fraction of an individual's lifetime.
Chronic intake		Exposure Factors Handbook: Glossary	Glossary and Key Word List	Definition: The long term period over which a substance crosses the outer boundary of an organism without passing an absorption barrier.
Chronic Population Adjusted Dose	cPAD	Pesticides Reregistration Glossary	Glossary and Key Word List
Chronic Reference Concentration	Chronic RfC	Integrated Risk Information System (IRIS) Glossary	Glossary and Key Word List	Definition: An estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure for a chronic duration (up to a lifetime) to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. It can be derived from a NOAEL, LOAEL, or benchmark concentration, with uncertainty factors generally applied to reflect limitations of the data used. Generally used in EPA's noncancer health assessments.
Chronic Reference Dose	Chronic RfD	Integrated Risk Information System (IRIS) Glossary	Glossary and Key Word List	Definition: An estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure for a chronic duration (up to a lifetime) to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. It can be derived from a NOAEL, LOAEL, or benchmark dose, with uncertainty factors generally applied to reflect limitations of the data used. Generally used in EPA's noncancer health assessments.
Chronic Response		Waste and Cleanup Risk Assessment Glossary	Glossary and Key Word List	Definition: The response of (or effect on) an organism to a chemical that is not immediately or directly lethal to the organism.
Chronic Reference Concentration	Chronic RfC	Integrated Risk Information System (IRIS) Glossary	Glossary and Key Word List	Definition: An estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure for a chronic duration (up to a lifetime) to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. It can be derived from a NOAEL, LOAEL, or benchmark concentration, with uncertainty factors generally applied to reflect limitations of the data used. Generally used in EPA's noncancer health assessments.
Chronic Reference Dose	Chronic RfD	Integrated Risk Information System (IRIS) Glossary	Glossary and Key Word List	Definition: An estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure for a chronic duration (up to a lifetime) to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. It can be derived from a NOAEL, LOAEL, or benchmark dose, with uncertainty factors generally applied to reflect limitations of the data used. Generally used in EPA's noncancer health assessments.
Chronic Study		Integrated Risk Information System (IRIS) Glossary	Glossary and Key Word List	Definition: A toxicity study designed to measure the (toxic) effects of chronic exposure to a chemical.
chronic study		Thesaurus of Terms Used in Microbial Risk Assessment	Thesaurus	Definition: A toxicity study designed to measure the (toxic) effects of chronic exposure to a chemical. [EPA 2003]
Chronic Tests		Waste and Cleanup Risk Assessment Glossary	Glossary and Key Word List	Definition: A toxicity test used to study the effects of continuous, long-term exposure of a chemical or other potentially toxic material on an organism.
Chronic Toxicity		Urban Watershed Management Research Terminology	Glossary and Key Word List	Definition: Toxic effects from long-term exposure to chemicals; usually nonfatal to organisms. Effects often consist of reduced growth and reproduction, as well as other physiological impacts.
Chronic Toxicity		Sediment Total Maximum Daily Loads (TMDLs) Glossary	Glossary and Key Word List	Definition: Toxicity impact that lingers or continues for a relatively long period of time, often one-tenth of the life span or longer. Chronic effects could include mortality, reduced growth, or reduced reproduction.
Chronic Toxicity		Terms of Environment	Glossary and Key Word List	Definition: The capacity of a substance to cause long-term poisonous health effects in humans, animals, fish, and other organisms.
Chronic Toxicity		Integrated Risk Information System (IRIS) Glossary	Glossary and Key Word List	Definition: The capacity of a substance to cause adverse human health effects as a result of chronic exposure.
chronic toxicity		Thesaurus of Terms Used in Microbial Risk Assessment	Thesaurus	Definition 1: The capacity of a substance to cause adverse human health effects as a result of chronic exposure. [EPA 2003] Definition 2: The effects of long term or repeated low level exposures to a toxic substance (cancer, liver damage, reproductive disorders, etc.). [EPA 2005e]
Chronic Toxicity		Pesticides Glossary	Glossary and Key Word List	Definition: The effects of long term or repeated low level exposures to a toxic substance (cancer, liver damage, reproductive disorders, etc.).
Chronic Toxicity		Web Taxonomy-Health Topics	Taxonomy	Definition: The capacity of a substance to cause long-term poisonous health effects in humans, animals, fish, and other organisms. [Terms of Env]
Chronic Toxicity		PRIA Fee Determination Glossary	Glossary and Key Word List	Definition: The potential for a substance to result in adverse effects to an organism after long-term exposure. The chronic toxicity of a compound is established through scientifically verifiable data from animal studies or human exposure tests.
Chronic Toxicity		I-BEAM Glossary of Terms	Glossary and Key Word List	Definition: The ability of a substance to cause long-term poisonous human health effects.
Subchronic		Terms of Environment	Glossary and Key Word List	Definition: Of intermediate duration, usually used to describe studies or periods of exposure lasting between 5 and 90 days.
Subchronic		Drinking Water Technical & Legal Terms	Glossary and Key Word List	Definition: Of intermediate duration, usually used to describe studies or levels of exposure between 5 and 90 days.
Subchronic Daily Intake	SDI		Abbreviation and Acronym List
Subchronic Exposure		Benchmark Dose Software (BMDS) Glossary of Terms	Glossary and Key Word List	Definition: Exposure to a substance spanning no more than approximately 10 percent of the lifetime of an organism.
Subchronic Exposure		Terms of Environment	Glossary and Key Word List	Definition: Multiple or continuous exposures lasting for approximately ten percent of an experimental species lifetime, usually over a three-month period.
Subchronic exposure		Exposure Factors Handbook: Glossary	Glossary and Key Word List	Definition: Repeated exposure by the oral, dermal, or inhalation route for more than 30 days, up to approximately 10% of the life span in humans (more than 30 days up to approximately 90 days in typically used laboratory animal species).
Subchronic Exposure		Integrated Risk Information System (IRIS) Glossary	Glossary and Key Word List	Definition: Repeated exposure by the oral, dermal, or inhalation route for more than 30 days, up to approximately 10% of the life span in humans (more than 30 days up to approximately 90 days in typically used laboratory animal species). [See also longer-term exposure.]
subchronic exposure		Thesaurus of Terms Used in Microbial Risk Assessment	Thesaurus	Definition 1: Exposure to a substance spanning approximately 10% of the lifetime of an organism. [EPA 2003] Definition 2: Of intermediate duration, usually used to describe studies or levels of exposure between 5 and 90 days. [EPA 2005b, RAIS 2004] Definition 3: A contact between an agent and a target of intermediate duration between acute and chronic. (Other terms, such as "less-than-lifetime exposure," are also used.) [IPCS 2004]
Subchronic Reference Concentration	Subchronic RfC	Integrated Risk Information System (IRIS) Glossary	Glossary and Key Word List	Definition: An estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure for a subchronic duration (up to 10% of average lifespan) to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. It can be derived from a NOAEL, LOAEL, or benchmark concentration, with uncertainty factors generally applied to reflect limitations of the data used. Generally used in EPA's noncancer health assessments.
Subchronic Reference Dose	Subchronic RfD	Integrated Risk Information System (IRIS) Glossary	Glossary and Key Word List	Definition: An estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure for a subchronic duration (up to 10% of average lifespan) to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. It can be derived from a NOAEL, LOAEL, or benchmark dose, with uncertainty factors generally applied to reflect limitations of the data used. Generally used in EPA's noncancer health assessments.
Subchronic Reference Concentration	Subchronic RfC	Integrated Risk Information System (IRIS) Glossary	Glossary and Key Word List	Definition: An estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure for a subchronic duration (up to 10% of average lifespan) to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. It can be derived from a NOAEL, LOAEL, or benchmark concentration, with uncertainty factors generally applied to reflect limitations of the data used. Generally used in EPA's noncancer health assessments.
Subchronic Reference Dose	Subchronic RfD	Integrated Risk Information System (IRIS) Glossary	Glossary and Key Word List	Definition: An estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure for a subchronic duration (up to 10% of average lifespan) to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. It can be derived from a NOAEL, LOAEL, or benchmark dose, with uncertainty factors generally applied to reflect limitations of the data used. Generally used in EPA's noncancer health assessments.
subchronic study		Thesaurus of Terms Used in Microbial Risk Assessment	Thesaurus	Definition: A toxicity study designed to measure effects from subchronic exposure to a chemical. [EPA 2003]
Subchronic Study		Integrated Risk Information System (IRIS) Glossary	Glossary and Key Word List	Definition: A toxicity study designed to measure effects from subchronic exposure to a chemical.
Chronic Bronchitis		EPA EV-Biological Substances-Humans-Human Diseases	Taxonomy	Definition 1: A subcategory of chronic obstructive pulmonary disease. The disease is characterized by hypersecretion of mucus accompanied by a chronic (more than 3 months in 2 consecutive years) productive cough. Infectious agents are a major cause of chronic bronchitis. (MSH2003_2003_05_12) [NIH National Cancer Institute Thesaurus] Definition 2: Condition characterized by persistent coughing, increased secretion from the bronchial mucosa, obstruction of the respiratory passages, scanty or profuse expectoration, and necrosis and fibrosis of the respiratory tract. (CSP2003) [National Cancer Institute Thesaurus]
Chronic Effect		EPA EV-Outcomes-Health Impacts	Taxonomy	Definition 1: An adverse effect that is measured by assessing an acceptable endpoint, and results from continual exposure over several generations, or at least over a significant part of the test species' projected life span or life stage.[40 CFR Appendix D to Part 132 (CFR 2013)] Definition 2: An effect which occurs as a result of repeated or long term (chronic) exposures. [EPA 2003][Thesaurus of Terms Used in Microbial Risk Assessment] Definition 3: An adverse effect on a human or animal in which symptoms recur frequently or develop slowly over a long period of time. [EPA 2005b][Thesaurus of Terms Used in Microbial Risk Assessment] Definition 4: An adverse effect on any living organism in which symptoms develop slowly over a long period of time or recur frequently. [EPA 2005e][Thesaurus of Terms Used in Microbial Risk Assessment] Definition 5: The effect of a stimulus that lingers or continues for a relatively long period, often one-tenth of the life span or more. The measurement of a chronic effect can be reduced growth, reduced reproduction, and such, in addition to lethality.[NPDES Permit Writers Glossary]
Chronic Exposure		EPA EV-Environmental Events-Exposure	Taxonomy	Definition 1: A continuous or intermittent long-term contact between an agent and a target. (Other terms, such as “long-term exposure,” are also used.) [IPCS 2004][Thesaurus of Terms Used in Microbial Risk Assessment] Definition 2: Repeated exposure by the oral, dermal, or inhalation route for more than approximately 10% of the life span in humans (more than approximately 90 days to 2 years in typically used laboratory animal species). [Integrated Risk Information System (IRIS) Glossary] Definition 3: Multiple exposures occurring over an extended period of time or over a significant fraction of an animal's or human's lifetime (Usually seven years to a lifetime.) [Terms of Environment][EPA 2005b][Thesaurus of Terms Used in Microbial Risk Assessment] Definition 4: Continuous or intermittent exposure to radiation over a long period of time. With chronic exposure, there is a delay between the start of the exposure and the observed health effect, such as cancer, benign tumors, cataracts, and potentially harmful genetic changes. [Radiation Protection Radiation Glossary] Definition 5: Repeated exposure by the oral, dermal, or inhalation route for more than approximately 10% of the life span in humans (more than approximately 90 days to 2 years in typically used laboratory animal species). [EPA 2003][Thesaurus of Terms Used in Microbial Risk Assessment] Definition 6: Continuous exposure, or multiple exposures, occurring over an extended period of time or a significant fraction of the animal’s or the individual’s lifetime. [EPA 2004][Thesaurus of Terms Used in Microbial Risk Assessment] Definition 7: Long-term exposure usually lasting 6 months to a lifetime.[Benchmark Dose Software (BMDS) Glossary of Terms] Definition 8: Repeated exposure by the oral, dermal, or inhalation route for more than approximately 10% of the life span in humans (more than approximately 90 days to 2 years in typically used laboratory animal species). [EPA 2003][Thesaurus of Terms Used in Microbial Risk Assessment] Definition 9: Multiple exposures occurring over an extended period of time, or a significant fraction of the animal’s or the individual’s lifetime. [RAIS 2004][Thesaurus of Terms Used in Microbial Risk Assessment] Definition 10: Contact with a substance that occurs over a long time (more than one year). [ATSDR 2004][Thesaurus of Terms Used in Microbial Risk Assessment]
Chronic Health Effect		EPA EV-Outcomes-Health Impacts	Taxonomy	Definition 1: An effect which occurs as a result of repeated or long term (chronic) exposures. [EPA 2003, EPA 2004] [Thesaurus of Terms Used in Microbial Risk Assessment] Definition 2: An adverse effect on a human or animal in which symptoms recur frequently or develop slowly over a long period of time. [EPA 2005b][Thesaurus of Terms Used in Microbial Risk Assessment] Definition 3: Having a persistent, recurring or long-term nature. [RAIS 2004, SRA 2004][Thesaurus of Terms Used in Microbial Risk Assessment] Definition 4: health condition that develops and persists over a long period of time. For example: A health condition with symptoms thatdo not start immediately; symptoms may stay a long time (typically several weeks or more); or fi rst symptoms may stop andthen come back.[National Biomonitoring Program Glossary]
Chronic Inhalation Study		EPA EV-Research-Research Resources-Analytical Methods & Protocols	Taxonomy	Definition: Prolonged and repeated exposure by inhalation for the life span of the test animal; technically, two years in the rat. [40 CFR 79.61 (CFR 2013)]
Chronic Kidney Diseases		EPA EV-Biological Substances-Humans-Human Diseases	Taxonomy	Definition: Gradual and usually permanent loss of kidney function resulting in renal failure. Causes include diabetes, hypertension, and glomerulonephritis. [National Cancer Institute Thesaurus]
Chronic Lung Diseases		EPA EV-Biological Substances-Humans-Human Diseases	Taxonomy
Chronic Obstructive Pulmonary Disease	COPD	EPA EV-Biological Substances-Humans-Human Diseases	Taxonomy	Definition 1: A chronic and progressive lung disorder characterized by the loss of elasticity of the bronchial tree and the air sacs, destruction of the air sacs wall, thickening of the bronchial wall, and mucous accumulation in the bronchial tree. The pathologic changes result in the disruption of the air flow in the bronchial airways. Signs and symptoms include shortness of breath, wheezing, productive cough, and chest tightness. The two main types of chronic obstructive pulmonary disease are chronic obstructive bronchitis and emphysema. [National Cancer Institute Thesaurus] Definition 2: A type of lung disease marked by permanent damage to tissues in the lungs, making it hard to breathe. Chronic obstructive pulmonary disease includes chronic bronchitis, in which the bronchi (large air passages) are inflamed and scarred, and emphysema, in which the alveoli (tiny air sacs) are damaged. It develops over many years and is usually caused by cigarette smoking. [National Cancer Institute Glossary]
Chronic Study		EPA EV-Research-Research Resources-Analytical Methods & Protocols	Taxonomy	Definition: A toxicity study designed to measure the (toxic) effects of chronic exposure to a chemical. [EPA 2003][Thesaurus of Terms Used in Microbial Risk Assessment]
Chronic Toxicity		EPA EV-Chemical Substances-Chemical Properties	Taxonomy	Definition 1: The capacity of a substance to cause adverse human health effects as a result of chronic exposure. [Integrated Risk Information System (IRIS) Glossary] Definition 2: Measure of toxicological responses that result from repeated exposure to a substance over an extended period of time (typically 3 months or longer). Such responses may persist beyond the exposure or may not appear until much later in time than the exposure. HRS measures of chronic toxicity include Reference Dose (RfD) values. [40 CFR Appendix A to Part 300 (CFR 2013)] Definition 3: Concurrent and delayed adverse effect(s) that occurs only as a result of a chronic exposure.[40 CFR 132.2 (CFR 2013)] Definition 4: Potential for a substance to result in adverse effects to an organism after long-term exposure. The chronic toxicity of a compound is established through scientifically verifiable data from animal studies or human exposure tests. [PRIA Fee Determination Glossary] Definition 5: The capacity of a substance to cause adverse human health effects as a result of chronic exposure. [EPA 2003][Thesaurus of Terms Used in Microbial Risk Assessment] Definition 6: The effects of long term or repeated low level exposures to a toxic substance (cancer, liver damage, reproductive disorders, etc.). [EPA 2005e][Thesaurus of Terms Used in Microbial Risk Assessment]
Chronic Toxicity Assay		EPA EV-Research-Research Resources-Analytical Methods & Protocols	Taxonomy	Definition 1: (Analysis for) the capacity of a substance to cause adverse human health effects as a result of chronic exposure. [Integrated Risk Information System (IRIS) Glossary] Definition 2: (Analysis for) toxic effects from long-term exposure to chemicals; usually nonfatal to organisms. Effects often consist of reduced growth and reproduction, as well as other physiological impacts. [Adapted from Urban Watershed Management Research Terminology]
Chronic Viral Hepatitis		EPA EV-Biological Substances-Humans-Human Diseases	Taxonomy	Definition: Chronic hepatitis caused by viruses, most commonly hepatitis viruses B and C.[National Cancer Institute Thesaurus]
Chronic Wasting Disease	CWD	EPA EV-Biological Substances-Animals-Animal Diseases	Taxonomy	Definition: Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) of deer and elk. To date, this disease has been found only in cervids (members of the deer family) in North America. First recognized as a clinical "wasting" syndrome in 1967 in mule deer in a wildlife research facility in northern Colorado, it was identified as a TSE in 1978. CWD is typified by chronic weight loss leading to death. There is no known relationship between CWD and any other TSE of animals or people. [USDA Food Safety and Inspection Service Glossary]
Serious Chronic Effect		EPA EV-Outcomes-Health Impacts	Taxonomy	Definition 1: Human disease processes or other adverse effects that have long latency periods for development, result from long-term exposure, are long-term illnesses, or are a combination of these factors and that are likely to result in death, severe or prolonged incapacitation, disfigurement, or severe or prolonged loss of the ability to use a normal bodily or intellectual function with a consequent impairment of normal activities. [40 CFR 723.50 (CFR 2013)] Definition 2: Human injury or human disease processes that have a long latency period for development, result from long-term exposure to a chemical substance, or are a combination of these factors and which are likely to result in death or severe or prolonged incapacitation. [40 CFR 721.3 (CFR 2013)]
Subchronic Dermal Toxicity		EPA EV-Chemical Substances-Chemical Properties	Taxonomy	Definition: Adverse effects occurring as a result of the repeated daily exposure of experimental animals to a chemical by dermal application for part (approximately 10 percent) of a life span.(2) Dose in a dermal test is the amount of test substance applied to the skin (applied daily in subchronic tests). Dose is expressed as weight of the substance (g, mg) per unit weight of test animal (e.g., mg/kg).(3) No-effect level/No-toxic-effect level/No-adverse-effect level/No-observed-effect level is the maximum dose used in a test which produces no observed adverse effects. A no-observed-effect level is expressed in terms of the weight of a test substance given daily per unit weight of test animal (mg/kg).(4) Cumulative toxicity is the adverse effects of repeated doses occurring as a result of prolonged action on, or increased concentration of the administered test substance or its metabolites in susceptible tissues. [40 CFR 798.2250 (CFR 2013)]
Subchronic Effect		EPA EV-Outcomes-Health Impacts	Taxonomy	Definition: Adverse effect, measured by assessing an acceptable endpoint, resulting from continual exposure for a period of time less than that deemed necessary for a chronic test. [40 CFR Appendix D to Part 132 (CFR 2013)]
Subchronic Exposure		EPA EV-Environmental Events-Exposure	Taxonomy	Definition 1: A contact between an agent and a target of intermediate duration between acute and chronic.(Other terms, such as "less-than-lifetime exposure" are also used.) (IPCS 2004) [Thesaurus of Terms Used in Microbial Risk Assessment] Definition 2: Exposure to a substance spanning approximately 10% of the lifetime of an organism. [EPA 2003][Thesaurus of Terms Used in Microbial Risk Assessment] Definition 3: Of intermediate duration, usually used to describe studies or levels of exposure between 5 and 90 days. [EPA 2005b, RAIS 2004][Thesaurus of Terms Used in Microbial Risk Assessment] Definition 4: Exposure to a substance spanning no more than approximately 10 percent of the lifetime of an organism. [Benchmark Dose Software (BMDS) Glossary of Terms]
Subchronic Inhalation Study		EPA EV-Research-Research Resources-Analytical Methods & Protocols	Taxonomy	Definition: Repeated exposure by inhalation for part (approximately 10 percent) of a life span of the exposed test animal. [40 CFR 79.61 (CFR 2013)]
Subchronic Inhalation Toxicity		EPA EV-Chemical Substances-Chemical Properties	Taxonomy	Definition: Adverse effects occurring as a result of the repeated daily exposure of experimental animals to a chemical by inhalation for part (approximately 10 percent) of a life span. [40 CFR 798.2450 (CFR 2013)]
Subchronic Oral Toxicity		EPA EV-Chemical Substances-Chemical Properties	Taxonomy	Definition: Adverse effects occurring as a result of the repeated daily exposure of experimental animals to a chemical by the oral route for a part (approximately 10 percent) of a life span. [40 CFR 798.2650 (CFR 2013)]
Subchronic Study		EPA EV-Research-Research Resources-Analytical Methods & Protocols	Taxonomy	Definition: A toxicity study designed to measure effects from subchronic exposure to a chemical. [EPA 2003][Thesaurus of Terms Used in Microbial Risk Assessment]
Subchronic Toxicity		EPA EV-Chemical Substances-Chemical Properties	Taxonomy	Definition: Adverse effects occurring as a result of the repeated daily exposure of experimental animals to a chemical for a part of their lifespan. [Adapted from 40 CFR 798.2650 (CFR 2013)]

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