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Definition
| Consequence which follows exposure to two or more physio-chemical agents which act jointly, but do not interact—commonly, the total effect is the simple sum of the effects of separate exposure to the agents under the same conditions; overall consequence which is the result of two chemicals acting together and which is the simple sum of the effects of the chemicals acting independently. |
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| Combined effect of two or more factors which is smaller than the solitary effect of any one of those factors. |
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| Metabolic conversion of a man-made compound to a more toxic derivative or one which has more of an effect on living organisms. |
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Definition
Indicator signaling an event or condition in a biological system or sample and giving a measure of exposure, effect, or susceptibility.
Note: Such an indicator may be a measurable chemical, biochemical, physiological, behavioral or other alteration within an organism. |
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Definition
Chemical conversion of a substance that is mediated by living organisms or enzyme preparations derived there from.
toxic chemical translocated from one organ or tissue to another, may be converted to a new compound or metabolite |
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Definition
| Agent (chemical, physical or biological) which is capable of increasing the incidence of malignant neoplasms, thus causing cancer. |
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Definition
Total amount of a substance administered to, taken up, or absorbed by an organism, organ, or tissue.
acute - single incident
chronic - repeated exposure |
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Definition
1.Concentration, amount or intensity of a particular physical or chemical agent or environmental agent that reaches the target population, organism, organ, tissue or cell, usually expressed in numerical terms of concentration, duration, and frequency (for chemical agents and micro-organisms) or intensity (for physical agents).
2.Process by which a substance becomes available for absorption by the target population, organism, organ, tissue or cell, by any route. |
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| Existence of inter-individual differences in DNA sequences coding for one specific gene, giving rise to different functional and (or) morphological traits. (affects toxic response) |
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Definition
| Time required for the concentration of a reactant in a given reaction to reach a value that is the arithmetic mean of its initial and final (equilibrium) values. For a reactant that is entirely consumed it is the time taken for the reactant concentration to fall to one half of its initial value. |
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Definition
| median lethal dose; of a toxin, radiation, or pathogen is the dose required to kill half the members of a tested population after a specified test duration |
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Definition
| Agent that can induce heritable changes (mutations) of the genotype in a cell as a consequence of alterations in or loss of genetic material. |
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Definition
| Chemically harmful to the cells of the kidney |
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Definition
| Able to produce chemically an adverse effect on the nervous system: such effects may be subdivided into two types CNS & PNS |
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Definition
| Means by which a toxic agent gains access to an organism by administration through the gastrointestinal tract (ingestion), lungs (inhalation), skin (topical), or by other routes such as intravenous, subcutaneous, intramuscular or intraperitoneal routes. |
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Definition
| Pharmacological or toxicological interaction in which the combined biological effect of exposure to two or more substances is greater than expected on the basis of the simple summation of the effects of each of the individual substances. |
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Definition
| Agent that, when administered prenatally (to the mother), induces permanent structural malformations or defects in the offspring. |
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Definition
| Material causing injury to living organisms as a result of physicochemical interactions |
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Definition
| process of metabolism in which the metabolite of a compound is more toxic than the parent drug or chemical |
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Term
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Definition
1.Capacity to cause injury to a living organism defined with reference to the quantity of substance administered or absorbed, the way in which the substance is administered and distributed in time (single or repeated doses), the type and severity of injury, the time needed to produce the injury, the nature of the organism(s) affected and other relevant conditions.
local - effect at point of contact/exposure
Systemic - effect at other places in body |
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Term
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Definition
| 1.Generally, the overall process of the absorption (uptake) of potentially toxic substances by the body, the distribution of the substances and their metabolites in tissues and organs, their metabolism (biotransformation), and the elimination of the substances and their metabolites from the body |
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Definition
| Scientific discipline involving the study of the actual or potential danger presented by the harmful effects of substances on living organisms and ecosystems, of the relationship of such harmful effects to exposure, and of the mechanisms of action, diagnosis, prevention and treatment of intoxications |
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Definition
| Closeness of a measured or computed value to its "true" value, where the "true" value is obtained with perfect information. Due to the natural heterogeneity and stochasticity of many environmental systems, this "true" value exists as a distribution rather than a discrete value. In these cases, the "true"... value will be a function of spatial and temporal aggregation. |
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Definition
the systematic or persistent distortion of a measurement process which causes errors in
one direction (i.e., the expected sample measurement is different than the sample's true
value). |
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Definition
| A process where chemicals are retained in fatty body tissue and increase in concentration over time; The process in which a substance is taken up by an aquatic organism through any route, including respiration, ingestion, or direct contact with water or sediment.; General term describing a process by which chemicals are taken up by an organism either directly from exposure to a contaminated medium or by consumption of food containing the chemical |
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Definition
| The increased accumulation and concentration of a contaminant at higher levels of the food chain; organisms higher on the food chain will have larger amounts of contaminants than those lower on the food chain, because the contaminants are not eliminated or broken down into other chemicals within the organisms. |
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Definition
Any missing data that impairs your ability to
meet your project goals; types Informational |
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Term
| Data Quality Objectives (DQO) |
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Definition
Qualitative and quantitative statements derived from the
DQO Process that clarify study objectives, define the appropriate type of data, and specify
the tolerable levels of potential decision errors that will be used as the basis for
establishing the quality and quantity of data needed to support decisions |
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Term
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Definition
an error made when drawing an inference from data in the context of hypothesis
testing, such that variability or bias in the data mislead the decision maker to draw a
conclusion that is inconsistent with the true or actual state of the population under study.
See also false negative decision error, false positive decision error |
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Definition
| The lowest concentration of a chemical that can be distinguished reliably from a zero concentration |
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Definition
| The time in which the concentration of a substance will be reduced by half |
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Definition
| Pesticides that contain phosphorus; short-lived, but some can be toxic when first applied |
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Term
| Persistent Organic Pollutants (POPs) |
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Definition
| A group of organic compounds/chemicals that are very resistant to decay/environmental degredation through chemical, biological, and photolytic processes. The banned pesticide DDT and PCBs fall into this category |
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Term
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Definition
| A measure of mutual agreement among individual measurements of the same property, usually under prescribed and similar conditions. Most desirably expressed in terms of the standard deviation, but can be expressed in terms of the variance, pooled estimate of variance, range, relative percent difference,... or other statistic. |
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Term
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Definition
an integrated system of management activities involving planning,
quality control, quality assessment, reporting, and quality improvement to ensure that a
product or service (e.g., environmental data) meets defined standards of quality with a
stated level of confidence. |
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Term
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Definition
the overall system of technical activities that measures the attributes and
performance of a process, item, or service against defined standards to verify that they
meet the stated requirements established by the customer. |
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Term
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Definition
he process of obtaining representative samples and/or measurements of a subset of a
population. |
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Term
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Definition
the error due to observing only a limited number of the total possible
values that make up the population being studied. It should be distinguished from errors
due to imperfect selection; bias in response; and errors of observation, measurement, or
recording, etc.
scientific method: the pri |
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Term
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Definition
| are metals in extremely small quantities that are present in animal and plant cells and tissue. They are a necessary part of nutrition and physiology. Ingestion of, or exposure to, excess quantities is often toxic. However, insufficient plasma or tissue levels of certain trace metals can cause pathology as well; as is the case with iron. |
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Term
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Definition
Differences among entities or states of an entity attributable to heterogeneity. Variability is an inherent property of nature and may not be reduced by measurement.
Range of toxic response or exposure that can cause a response from one person to the next depending on other factors (genetics, medical conditions) include spatial, temporal, and inter-individual |
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Term
| Acceptable daily intake (ADI) |
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Definition
| The amount of a chemical a person can be exposed to on a daily basis over an extended period of time (usually a lifetime) without suffering deleterious effects. |
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Term
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Definition
| the amount of a substance in contact with the primary absorption boundaries of an organism and available for absorption |
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Term
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Definition
| The mean amount of an agent to which a person is exposed on a daily basis, often averaged over a long period of time. U.S. EPA is transitioning from average daily dose methodologies to more refined aggregate and cumulative approaches for estimating exposure across each lifestage. See also Lifetime average... daily dose (LADD) and Time-averaged exposure |
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Term
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Definition
| The degree to which a substance becomes available to the target tissue after administration or exposure |
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Term
| cancer slope factor (CSF) |
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Definition
| An upper bound, approximating a 95% confidence limit, on the increased cancer risk from a lifetime exposure to an agent. This estimate, usually expressed in units of proportion (of a population) affected per mg/kg/day, is generally reserved for use in the low-dose region of the dose-response relationship,... that is, for exposures corresponding to risks less than 1 in 100. |
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Term
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Definition
| The sum of more than one hazard quotient for multiple substances and/or multiple exposure pathways. The HI is calculated separately for chronic, subchronic, and shorter-duration exposures. |
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Term
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Definition
| The ratio of an exposure level to a substance to a toxicity value selected for the risk assessment for that substance (e.g., LOAEL or NOAEL). |
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Term
| lifetime average daily dose (LADD) |
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Definition
| Figure for estimating excess lifetime cancer risk |
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Term
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Definition
| Lowest-Observed-Adverse-Effect Level (LOAEL): The lowest exposure level at which there are biologically significant increases in frequency or severity of adverse effects between the exposed population and its appropriate control group |
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Term
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Definition
| An ATSDR estimate of daily human exposure to a hazardous substance at or below which that substance is unlikely to pose a measurable risk of harmful (adverse), noncancerous effects. MRLs are calculated for a route of exposure (inhalation or oral) over a specified time period (acute, intermediate, or chronic). MRLs should not be used as predictors of harmful (adverse) health effects [see reference dose]. |
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Term
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Definition
| no observed adverse effect level - highest exposure level at which there are no biologically significant increases in the frequency or severity of adverse effect between the exposed population and its control. some effects may be produced at this level, but they are not considered adverse or precursors of adverse effects |
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Term
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Definition
| Chemical equilibrium condition where a chemical's concentration is apportioned between two different phases according to the partition coefficient, which is the ratio of a chemical's concentration in one phase to its concentration in the other phase. |
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Term
| reasonable maximum exposure (RME) |
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Definition
| The maximum exposure reasonably expected to occur in a population |
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Term
| reference concentration (RC) |
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Definition
| estimate of a continuous inhalation exposure to the human population that is likely to be without an appreciable risk of deleterious effects during a lifetime.can be derived from NOAEL,LOAEL, etc. used in EPA noncancer health assessments |
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Term
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Definition
one of several 10 fold default factors use in operationally deriving the RD & RC; account for variation in susceptibility, uncertainty interspecies, subchronic to chronic, LvsN, incomplete database
Factors used in the adjustment of toxicity data to account for unknown variations. |
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Term
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Definition
| The daily exposure level which during an entire lifetime of a human appears to be without appreciable risk of the basis of all facts known at the time |
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