Toxicity tests and bioassays

Hill and co-workers [29] give some well formulated definitions  

A toxicity test is an experiment in which organisms of a single species are exposed in the laboratory to a clean natural sample (soil, sediment or water) which has been spiked with a known chemical or mixture of chemicals, generally at a range of concentrations. The purpose is to measure the degree of response associated with specific concentrations of the chemical(s). 

The term biotests is also very often used in the literature. It could be used as universal expression if both, toxicity tests and bioassays are mentioned in one sentence or if a general explanation is formulated. 

To distinguish between toxicity tests and bioassays is not only of theoretical relevance. From the first, a clear dose-response graph could be drawn and effect concentrations 

---

Hill, I.R., Matthiessen, R, and Heimbach, F. (Eds.) (1993). Guidance Document on Sediment Toxicity Tests and Bioassays for Ereshwater and Marine Environments. SETAC Europe Workshop on Sediment Toxicity Assessment. Renesse, the Netherlands, November 8-10, 1993. 

Distinguishing between toxicity tests and bioassays is not only of theoretical relevance. From toxicity tests, a clear dose-response graph could be drawn and effect concentrations (ECio, EC50 and EC90) as well as LOEC and NOEC could be calculated. The evaluation of bioassays should preferably be limited to the expression of inhibition values of the original sample and the calculation of dilution rates (G-values) at which a specific rate of inhibition, most commonly 10%, is reached. For example, the G-values derived from a wastewater treatment process should provide an estimation basis for the treatment plant operator regarding the possible inhibition effect of a certain wastewater stream (for methods see DIN-standards listed in Table 4.2). 

I.R. Hill, P. Matthiessen and F. Heimbach in Guidance Document on Sediment Toxicity Tests and Bioassays for Freshwater and Marine Environments, Society of Environmental Toxicology and Chemistry, Renesse, The Netherlands, 1993. 

Persoone, G., Janssen, C., and De Coen, W. (Eds.) (2000). New Microbiotests for Routine Toxicity Testing and Screening—An extensive review of bioassay systems and toxicity tests that also contains some valuable discussion of the principles that underlie them. 

A number of scientific publications have emerged since the 1950s, including the work of Doudoroff (1976) and Doudoroff and Katz (1950, 1953) on the use of so-called pickle-jar tests and the effects of industrial wastes. Doudoroff el al. (1951) developed a single-species fish bioassay, Cairns (1956, 1957) reported the physiological effects of temperature changes on fish and Henderson (1957) considered the application of bioassays for the safe disposal of toxic wastes. This early work on fish helped to establish aquatic toxicity testing and was followed quickly by the... 

A number of respirometers are available for bioassay purposes. A common type is the Arthur Respirometer used in toxicity testing and also for... 

Reproductive and developmental toxicity (ISO 10993-3) Reproductive/deve-lopmental toxicity tests or bioassays should only be conducted when the device has potential impact on the reproductive potential of the subject. The application site should be considered. ... 

Not all cyanobacterial blooms and scums contain detectable levels of toxins. Indeed, the incidence of toxicity detection by mouse bioassay, and toxin detection by HPLC among environmental samples, ranges from about 40% to However, in view of this high occurrence, it is the policy of regulatory authorities and water supply operators in some countries to assume that blooms of cyanobacteria are toxic until tested and found to be otherwise. In the absence of available analytical facilities or expertise or for logistical reasons, this precautionary principle should be regarded as sensible and prudent. 

Mud Toxicity Test. Presently, the only toxicity test for drilling fluids having an EPA approval is the Mysid shrimp bioassay. The test was developed in the mid-1970s as a joint effort of the EPA and the oil industry. 

The mysid shrimp, Mysidopsis bahia, is the test organism for the liquid and suspended particulate phases. This species has been shown to be exceptionally sensitive to toxic substances and is considered to be a representative marine organism for bioassay testing by EPA. An LCj, is determined the suspended particulate phase (SPP) bioassay tests. 

Toxicity Bioassay. Ninety-six hour acute toxicity tests were conducted on the effluent streams of major industries. A static renewal procedure was used in which waste waters of various dilutions were renewed at 24 hour intervals over a 96 hour period. Rainbow trout was used as the test organism. Tests were conducted at 13°C in 20 liter aquaria according to standard procedures (22), Results are summarized in Table 8. Chemical and toxicity test results indicate that the trace element quantities identified in Table 8 are not acutely toxic under the prevailing conditions and unlikely to pose an acute threat to aquatic life. In this case a chronic toxicity assessment would require additional research. 

During the 1970 s and early 1980 s a large number of test methods were developed to measure the toxic potency of the smoke produced from burning materials. The ones most widely used are in refs. 29-32. These tests differ in several respects the conditions under which the material is burnt, the characteristics of the air flow (i.e. static or dynamic), the type of method used to evaluate smoke toxicity (i.e. analytical or bioassay), the animal model used for bioassay tests, and the end point determined. As a consequence of all these differences the tests result in a tremendous variation of ranking for the smoke of various materials. A case in point was made in a study of the toxic potency of 14 materials by two methods [33]. It showed (Table I) that the material ranked most toxic by one of the protocols used was ranked least toxic by the other protocol Although neither of these protocols is in common use in the late 1980 s, it illustrates some of the shortcomings associated with small scale toxic potency of smoke tests. 

Barata C, Alanon P, Gutierrez-Alonso S, Riva MC, Fernandez C, Tarazona JV (2008) A Daphnia magna feeding bioassay as a cost effective and ecological relevant sublethal toxicity test for environmental risk assessment of toxic effluents. Sci Total Environ 405(l-3) 78-86... 

---