ROTOXKIT F

The Acute ROTOXKIT F contains all the materials necessary to perform six acute toxicity tests and the Short-Chronic ROTOXKIT F three short-chronic bioassays.

The test species is the freshwater rotifer Brachionus calyciflorus (rotifers are ecologically very important members of many aquatic communities. With copepod and cladoceran crustaceans they are the major constitutents of freshwater zooplankton, with turnover rates which are higher than those of the crustaceans).

Easy to follow instructions and detailed illustrations are provided in the hits for the conduct of range-finding and definitive tests. The test organisms are included in the hits as “dormant” eggs (cysts) which can easily be hatched on demand, in less than 24 hours, to supply the live biota for the conduct of the assays.

The Acute ROTOXKIT F is a 24 h assay based on mortality of the test organisms, with calculation of the 24 h LC50.

The Short-Chronic ROTOXKIT F measures the decrease in reproduction of the rotifers under toxic stress alter 48 h exposure, with calculation of the 48 h median growth inhibition (48 h EC50).

Left: Acute ROTOXKIT, Right: Short-Chronic ROTOXKIT.

Contents:

• Tubes with cysts, concentrated hatching and toxicant dilution media, hatching/test containers and micropipettes for the transfer of the organisms.
• Detailed standard operational procedure brochure, abbreviated bench protocol, data scoring sheets and graphical LC50 calculation sheets.
• For the short-chronic tests tubes with live micro-algae immobilized in algal beads, a vial with matrix dissolving medium, tubes with Spirulina powder and a vial with Lugol fixative for easy counting of the rotifers.
• Specification sheet with batch number of the cysts, the media and the algal beads.

Reproducibility:

• Cysts of high quality produced in strictly controlled conditions preclude variability associated with recruitments maintenance of live stocks in conventional bioassays.
• Highly uniform quality of the test medium is achieved by simple dilution of concentrated solutions of selected salts with deionized water.
• Standardized microplate test containers constructed of biologically inert materials ensure uniform exposure conditions.
• A quality control test with a reference chemical is described in detail, for accuracy and reproducibility check.

Sensitivity:

• Very chemical dependent, but highly sensitive to particular chemicals and mixtures.
• Growth inhibition NOEC´s determined with the short-chronic ROTOXKIT F are ecologically meaningful thresholds for the impact of toxicants on this important group of biota in aquatic food chains.

Validation:

• The acute toxicity tests with B. calyciflorus is an ASTM Standard since 1991.
• A 48h growth inhibition test with rotifers (including Brachionus calyciflorus as test species) is proposed in the 20th Edition (1998) of “Standard Methods for the Examination of Water and Wastewater”; the short-chronic microbiotest is also taken in consideration as a new AFNOR Guideline in France.

Cost-effectiveness:

• Cysts can be hatched on demand, eliminating the need and the costs of continuous culturing and maintenance of test organisms.
• Minimal equipment needed for test performance: dissecting microscope - small incubator - conventional laboratory glassware.
• Shelf-life of cysts guaranteed for several months when stored properly, reducing test scheduling constraints.

User-friendliness:

• Specially designed “all in one” microplates with hatching trough, rinsing troughs and 36 (acute) or 48 (short-chronic) test wells for easy and rapid transfer of the test organisms under a dissecting microscope.
• Total performance time approximately 1 h for the acute assays and 2 h for the short-chronic tests.

Acute ROTOXKIT F short test protocol.

Short-Chronic ROTOXKIT F short test protocol.