This table contains information on the susceptibility of fish to various chemicals, as measured by the concentration that leads within a certain period, to the death of 50% of the test fish i.e., the lethal concentration (LC50).

Fish are commonly used for bioassays Tests of this sort are routinely conducted to assess the toxicity of various chemicals that are (to be) released into the environment (hence ‘ecotoxicology’) and fish are commonly used for such bioassays, which are typically conducted for periods of 24, 48 or most commonly 96 hours.

The table was designed to capture the essential features of such experiments, as reported in the ecotoxicological literature, and consists of 3 parts, dealing with (i) the fish, (ii) the substances tested and (iii) the experimental conditions and results. The fields in each of these parts are as described below.

Fields Species and family: The scientific name and affinities of the test fish.

Number: Indicates the number of specimens used in the experiment.

Sex: A choice field with options: females; males; undefined (default).

Weight: Indicates the minimum, maximum and mean or modal weight (in g) of the fish used in the experiments.

Length: Indicates the mean or modal size. The length type is generally not indicated in the ecotoxicological literature, and is thus omitted here; when available, it is indicated in the Comment field (see below).

Stage: Indicates the stage of development of the fish used. The choices are: eggs, larvae, juveniles, adults, juveniles/adults (default).

Fields describing the test substances:

Chemical substances are classified into major groups Chemical group I: Enables a rough classification of chemical substances commonly tested. The choices are: hydrocarbon, metal, amine, organophosphate, carbamate, organic acid, alcohol, dioxin, dibenzofuran, polychlorinated biphenyl, alkylbenzene, phenol, chloroaniline, cresol, azocompound, bipiridyl, organometallic, inorganic, other group.

Chemical name: A free text field for the precise identification of the test substance.

Common name: A free text field for the generic or commercial name of the test substance.

Chemical group II: Enables a finer classification of test substances and presently consisting of 18 groups (e.g., aliphatic hydrocarbon; aromatic hydrocarbon; polynuclear aromatic hydrocarbon; chloroethane; chlorobenzene; pyrethroids; organochlorines; other groups). More options are likely to be added as the database grows.

A vehicle is the liquid into which the test substance is diluted Vehicle: A choice field for the liquid into which the test substance is diluted; the choices are: water; acetone; methanol; ethanol; none; other. In case ‘other’ applies, the vehicle is mentioned in the comment field.

Purity I: Refers to the purity of the test substance in %.

Purity II: Refers to the purity of the test substance, as expressed by the choices: reagent; technical; practical; mixture (see Comments); formulation; other (see Comments).

Use: Describes the use for which the test substance is put or intended: pharmaceutical; food additive; propellant; dielectric fluid; bactericide; fungicide; herbicide; insecticide; antibiotic; other.

Fields describing the experimental conditions and results:

Temperature: A numeric field, with ° C as unit.

pH: A numeric field for entries without units and ranging between 2 and 14.

Salinity: A numeric field for entries ranging between 0 and 40 ppt.

Dissolved oxygen: A numeric field for entries, in mmHg and/or mg× l-1.

saturation: A calculated field for 100% and actual oxygen saturation, based on the entries in the dissolved oxygen, temperature and salinity fields.

Alkalinity: A numeric field for entries, in CaCO3× l-1.

Flow: Indicates whether or not water flow was maintained through the test chamber.

Flow rate: A numeric field, to be filled, when the Flow field is ‘yes’, with an entry in ml × hour-1.

Bioassays are often combined with stresses Applied stress: Describes stresses other than the test substance itself, to which the test fish may be exposed prior to, or during the experiment. The choices are: none specified; temperature (too high or too low); photoperiod; feeding; starvation; toxins; hypoxia; hypercapnia; salinity; high pH; low pH; sedative; transparent; other stresses (to be specified in the Comments field).

LC50: Presents the result of an experiment, and the key information in this table, in mg× l-1.

Exposure time: Specifies the time for which the above LC50 applies, in hr.

MainRef: A reference from which the LC50 and related information were extracted.

Comments: A text field, for complementing the information included in the above fields.

It is hoped that this table will reduce the need for further LC50 experiments The table presently contains about 1,500 records, pertaining to over 300 substances and involving over 100 test species of fish, extracted from nearly 200 references (see pie charts accessible from the Graph Menu). This is but a small fraction of the available information, and we plan to expand our coverage, notably by inclusion of the many fish records cited in Ramamoorthy and Baddaloo (1995). Also, we would appreciate receiving reprints covering species or substances not yet covered. It is hoped that this table will at some point allow for generalizations that would explain the different susceptibilities of fishes to different substances and thus reduce the need for further LC50 experiments.

How to get there You get to the ECOTOXICOLOGY table by clicking on the Biology button in the SPECIES window and the Ecotoxicology button in the BIOLOGY window. The internal name of the table is LC50.

Internet The ECOTOXICOLOGY table was not yet available on the Internet in November 2000.

Reference Ramamoorthy, S. and E.G. Baddaloo. 1995. Handbook of chemical toxicity profiles of biological species. Vol. 1. Aquatic species. CRC Press, Boca Raton, Florida. 386 p.
Cristina Bárcenas-Pazos