Technical terms

Acute toxicity

AF: Acccumulation factor
[note] The ratio of the chemical's concentration in the medium and its concentration in the organism at any given time during the exposure phase when no steady state is reached. (ref. ID; 6670)

APHA: American Public Health Association
[note] Standard methods for the examination of water and wastewater.

ASTM (American Society for Testing and Materials), 1995
[note] Standard guide for determination of the bioaccumulation of sediment-associated contaminants by benthic invertebrates. American Society for Testing and Materials, E 1688-95.

[note] Bioaccumulation is defined as the increase of a chemical in an organism relative to the concentration in the ambient medium or the food, consists of several processes and arises from the sum of all possible exposure routes. These processes are on one hand the bioconcentration, which results exclusively from uptake from the ambient medium via the body surface. Biomagnification on the other hand is defined as the increase of body concentration resulting from contaminated food, usually along a predator-prey series. (ref. ID; 6670)

BAF: Bioaccumulation factor
[note] The use of BAFs depends on the assumption that the concentration of chemicals in organisms is a linear, no-threshold function of concentrations in soil. (ref. ID; 6016)
BAF is defined as the chemical's concentration in the organism, for instance a benthic oligochaete, divided by its concentration in the medium, for example the sediment, which serves both as medium and food; the BAF takes into account all uptake pathways. (ref. ID; 6670)

BCF: Bioconcentration factor
[note] BCF is the quotient of the chemical's concentration in the organisms, for example a fish, and its concentration in the ambient water at steady state. (ref. ID; 6670)


BLM: Biotic ligand model
[note] The BLM was originally developed to predict Cu toxicity to fish (Paquin et al. 2002). To date the aquatic biotic ligand models (a-BLM) have been developed for several vertebrate species to predict acute as well as chronic toxicity of metal (De Schamphelaere et al. 2003). in analogy with the a-BLM, metal toxicity to terrestrial organisms and plants can also be predicted using the concept of BLM. A fundamental assumption of the BLM is that toxicity is driven by exposure to dissolved metal alone, rather than combined toxic effects from dissolved and dietary exposures (Niyogi and Wood, 2004). Thus, development of a terrestrial biotic ligand model (t-BLM) that predicts site-specific metal toxicity in soil is only possible if the uptake and toxicity is caused by exposure to metals in the aqueous phase. (ref. ID; 7156)

BSAFs: Biota-sediment accumulation factors

CA model: Concentration addition model
[note] One of the mathematical models used in pharmaceutical research have been adapted for the toxic evaluation of chemical mixtures in the environment. See IA model. The CA model assumes that chemicals with the same mode of action (MoA) will act additively. This conceptual model is defined as a summation of the relative toxicities of the individual component in mixture (ref. ID; 6754)

Carboxylesterases (CbEs; EC
[note] Carboxylesterases (CbEs; EC are hydrolases that cleave carboxyl esters to yield the corresponding alcohol and carboxylic acid (Sogorb & Vilanova, 2002; Wheelock et al., 2005). These enzymes paticipate in the detoxification of pyrethroid, carbamate and some organophosphorus insecticides. Inhibition of CbE activity by pesticides has been used as a biomarker of pesticide exposure in many aquatic and terrestrial organisms (Wheelock et al., 2008). (ref. ID; 6753)

Cholinesterases (ChEs)
[note] Multiple ChEs with varying sensitivity to pesticide inhibition are frequently found in the same tissue, potentially leading to contraindicative data if total activity is used (Stenersen, 1980; Bocquene et al., 1997; Aamodt et al., 2007). It is therefore recommended that the tissue distribution and biochemical activity of ChE are characterized before use as a biomarker of pesticide exposure. (ref. ID; 6753)

CAS: Chemical Abstracts Service registry number

CBR: Critical body residue
[note] McCarty (1986) derived that the molar whole body concentration of nonpolar narcotic chemicals at the time of death, referred as lethal body burden or critical body residue (CBR), is constant. This concept is based on idea that residue levels at the cell membranes (where the toxic action of these chemicals takes palace) are well correlated with the whole body concentrations. The use of CBR has been applied also to chronic endpoints. (ref. ID; 4445)
See; Wei-chun (Wim) Ma, 2005 (ref. ID; 6786)

CEC: Cation exchange capacity

Chronic toxicity

Comet assay
[note] The comet assay is a micro-electrophoretic technique that allows the direct visualisation of DNA single-strand breaks (SSBs) within individual cell genomes. (ref. ID; 6137)

Condition Index (CI) (see: ref. ID; 6909 Langdon, 1999)
Condition index scores:
2 - good muscle tone, earthworm responding rapidly to stimulation.
1 - poor muscle tone, responding fairly rapidly to stimulation, or good muscle tone, but slow in responding to stimulation.
0 - poor muscle tone, no response to stimulation.
Assessment was carried out 'blind', with an assistant presenting the specimens for assessment to the recorder.

CYA: Cytochrome P450

CYPIA: Cytochrome P4501A

Dose-response relationship
[note] Normal distribution curve.

EDCs: Endocrine disrupting chemicals

Eco-SSLs: Ecological soil screening levels
[note] The ecological risk assessment of contaminants at Superfund sites.

EEC: Estimated environmental concentration

[note] Electro(nucleo)philic activity can be thought of as a chemical's ability to have a covalent interaction with a biological system (Mekeyan et al. 1994). As noted by Hermens (1990), such interactions typically involve substitution or conjugation of electron-rich groups to nucleophilic sites in cellular macromolecules (e.g. proteins). The interaction may occur with the initial toxicant or with a metabolite (the original molecule being defined as the proelectrophile). (ref. ID; 3327)

[note] The loss of a chemical from the organism by active or passive processes. (ref. ID; 6670)

Endpoint: Including following items.
AC50 (Concentration inducing a avoidance of 50%)
IC25 (Estimated concentration causing 25% reduction of measured endpoints in relation to the control)
IC50 (50% inhibition concentration)
ICG50 (50% population growth inhibitory concentration)
IG50 (Median growth inhibition concentration)
EC10 (10% effective concentration)
EC20 (20% effective concentration)
EC50 (Median effective concentration, effective concentration for 50% growth inhibition)
HC5 (Hazardous concentration for five percent of the species) (see: ref. ID; 6956)
ILL (incipient lethal levels)
LC50 (50% lethal concentration)
LD50 (50% lethal dose)
LT50 (The median survival time, the time at which 50 per cent of the test organisms are dead)
LOEAC (Lowest-observable-adverse-effect concentration)
LOEC (Lowest-observed-effect concentration, the lowest observed effect concentration) (see: ref. ID; 6967)
MATC (Maximum acceptable toxicant concentration)
MIC (Minimum inhibitory concentration)
MTI (Mixture toxicity index)
NEL (no-effect levels)
NOEAC (No-observable-adverse-effect concentration)
NOEC (No-observed-effect concentration, the highest no observed effect concentration)
NOEL (The predicted no observable effect level)
TLm value (Median tolerance limit for fish (fish-toxicity))
TUs (Toxic Units) see Joint Toxicity Effect Model

EqP: The equilibrium partitioning theory
[note] The EqP theory has been used to describe the fate of chemical in sediment-water system. The EqP theory assumes that the distribution of hydrophobic organic chemicals is in equilibrium between the lipids of the organisms, the pore water, and the organic carbon (OC) of the sediment and that the partitioning between the lipids and OC results in a more or less constant. (ref. ID; 6721)

EU, 1996
[note] Technical Guidance Documents in support of the Commission Directive 93/67/EEC on Risk Assessment for New Notified Substances, and the Commission Regulation (EC) 1488/94 on Risk Assessment for Existing Substances.

FEAL: Amorphous iron and aluminium oxides

FIAM: Free ion activity model
[note] FIAM use for predict of metal uptake in aquatic systems.

GST: Glutathione-S-transferase

IA model: Independent Action model
[note] One of the mathematical models used in pharmaceutical research have been adapted for the toxic evaluation of chemical mixtures in the environment. See CA model. The IA model is usually used if the question asked is whether the probability of toxicity to one chemical is independent from the probability of toxicity exposure to another chemical. (ref. ID; 6754)

ILLs: Incipient lethal levels (see: ref. ID; 6899, 6900)

ISM: Integrated soil microcosm

ISO: International Standard Organization
ISO 11267: Soil quality - Inhibition of reproduction of collembola (Folsomia candida) by soil (1998).
ISO 11268-2: Soil quality - Effects of pollutants on earthworms (Eisenia fetida) - Part 2: Determination of effects on reproduction (1998).
ISO 16387: Soil quality: Effects of pollutants on Enchytraeidae (Enchytraeus sp) - Determination of effects on reproduction and survival (2003).

Joint Toxicity Effect Model
[note] Expected joint effects were calculated on the basis of simple similar action as null model (same mode of action, but no interaction). The reference point of Simple Similar Action (SSA) was calculated after scaling the concentrations of the chemicals. The common scale was defined by the relative toxicities of the chemiclas (e.g., the 4-week EC50 for reproductive activity). For each chemical, this concentration was defined as 1 toxic unit (TU, dimensionless), and other concentrations were expressed accordingly. Under SSA, the effect of x% in a mixture after n weeks of exposure is expected at a summed concentration of 1 TU. Observed joint effects were categorized either as similar to concentration additive (TU (observed) = 1), or as more or less than concentration additive (resp. TU (observed) < 1 or > 1). (ref. ID; 6836)

Kow: The octanol/water partition constant


Metallothioneins (MTs)
[note] Metallothioneins constitute a family of low-molecular weight, cysteine-rich, metal binding proteins that occur throughout the animal kingdom and whose synthesis is induced by various and other factors. These proteins appear to play a role in the regulation of essential metals as well as in metal-detoxification. (ref. ID; 6109)
Metallothioneins are cysteine rich cationic metal-binding proteins that have been linked to (1) regulation and detoxification of trace elements, (2) protective function against stress by chemical radical, and (3) activities of gene regulatory compartments (Stegeman et al., 1992) (ref. ID; 6129)
Metallothoneins are cadmium-, zinc-, and copper-containing sulphur rich proteins typically 6-7 kDa in molecular weight with an omnipresent phylogenetics distribution ranging from plants and prokaryotes to higher eukaryotes. Identified functions of MT include the metabolism and homeostasis of essential trace metals such as zinc and copper, the protection against oxidative damage, acting as chaperones for protein folding and the protection from cadmium and other toxic stressors. (ref. ID; 6738)

MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay
[note] The MTT assay is widely established as an indicator of in vitro mitochondrial proliferation and metabolism. It is based on the principle of the reduction of the yellow MTT exclusively by metabolically active cells to a blue formazan salt. After reduction, the formazan salt is transported to the outside by exocytosis. The difference in the absorption of the yellow monotetrazolium salt and the blue formazan products can be measured photometrically at a wavelength of 570 nm. The response of the MTT cytotoxicity assay is also strongly dependent on the cell concentration. (ref. ID; 6710)

[note] Narcosis is the general term that describes the interaction between a xenobiotic and the cellular membrane, the theoretical site of action. Narcotic effects are thought to result in noncovalent interactions such as the disruption of van der Waals forces between lipid and/or protein components within the membrane. (ref. ID; 3327)

NRRT: Neutral red retention time
[note] NRRT has been used as an earthworm biomarker for lysosomal membrane damage caused by environmental contaminants (ref. ID; 4958)
As a biomarker for cellular stress, NRRT assay has been suggested by Weeks and Svendsen (1996) to evaluate the effects of metals on earthworms.
The NRRT assay is based on the appraisal of changes in the lysosomal membrane stability caused by toxic stress. Netural red (3-amino-m-dimethylamino-2-methylphenazine hydrochloride) is a lipophilic, slightly basic dye that is taken up in uninjured cells and accumulated in the lysosomes. Over time, the dye trends to leak out of the lysosomes into the cytosol which is then stained by the dye. With increasing relation to the damage, the retention time i.e. the time the colorant remains solely in the lysosomes, decreases in relation to the damage and the dose of the toxicant. The leakage of the dye into the cytosol can be evaluated by light-microscopy.

OECD: Organization for Economic Cooperation and Development
OECD 202: Daphnia Acute Immobilization Test
OECD 207: Earthworm Acute Toxicity Test
OECD 208: Terrestrial Plants Growth Test

PBTs: Persistent bioaccumulative toxic chemicals

PEC: Predicted environmental concentration
[note] Predicted environmental concentration derived from chemical analysis measurements. (ref. ID; 6137)

PNEC: Predicted no effect concentration
[note] Predicted no effect concentration from testing of chemical at specific concentrations in surrogate species. (ref. ID; 6137)

PPS: Permeable Pavement Structures

PRCs: Principal Response Curves
[note] PRC is based on the Redundancy Analysis ordination technique, the constrained form of PCA (Principal Components Analysis). (ref. ID; 4956)

Heat-stable proteins (e.g. metallothioneins)
Heat-denatured proteins (e.g. enzymes)

QSARs: Quantitative structure-activity relationships. A model for predicting the toxicity
[note] Development of QSARs dependents on the data sets, chemical descriptors, and statistical methods with which the relationship between toxicity potency and structural properties can be defined. QSARs have the advantages of high speed and low costs, especially in comparison with performing the experiments. (ref. ID; 6709)

Soil profile distribution (mainly used for Oligochaetes) (ref. ID; 6107)
Anecic species: Live across the all profile. Deep burrowing. (ref. ID; 6107)
Epigeic species: Upper species (soil depth 0-5 cm). Litter dwellers. (ref. ID; 6107)
Endogeic species: Deeper species (soil depth 1-15 cm). Horizontal burrowing, surface soil dwellers. (ref. ID; 6107)

TME: Terrestrial model ecosystem

Toxicokinetic-toxicodynamic (TK/TD) model
[note] This models describe the processes that mechanistically link exposure to effects in an individual organism and can therefore be used to understand differences in response to the same time-variable exposure between different species. Toxicokinetics (e.g., uptake and elimination dynamics, bioconcentration) predict the time course of concentrations within an organism in relation to concentations in the external medium. Toxicodynamics describe the time course of damage, subsequent effects, and repair processes in the target organisms based on specific patterns of exposure to the test compound. (ref. ID; 7139)

TWA: Time-weighted average

U.S. EPA, 1995
[note] Great Lakes Water Quality Initiative Techinical Support Document for the procedure to determine bioaccumulation factors. EPA 820-8-95-005