Acute aquatic tests

Acute aquatic tests normally last 2 to 4 days depending on the test organisms. Chronic tests for invertebrates, like daphnia, last for 21 to 28 days and may involve several generations of offspring. We are always looking for test organisms that will reach maturity faster so we can evaluate the effect of the test substance on multiple generations in a shorter period of time. 

Acute aquatic tests duration, 133 species selection, 133 Advisory function of QAU, 114 Agricultural chemicals residue field trials program, quality assurance, 99-106... 

For the sample search on aquatic toxicity of atrazine, 1459 results were found. An excerpt on the daphnia acute aquatic toxicity tests (EC50. LC.50) is prc.scnted in Figure 5-33. 

The impact that a silver compound has in water is a function of the free or weaMy complexed silver ion concentration generated by that compound, not the total silver concentration (3—5,27,40—42). In a standardized, acute aquatic bioassay, fathead minnows were exposed to various concentrations of silver compounds for a 96-h period and the concentration of total silver lethal to half of the exposed population (96-h LC q) deterrnined. For silver nitrate, the value obtained was 16 )-lg/L. For silver sulfide and silver thiosulfate complexes, the values were >240 and >280 mg/L, respectively, the highest concentrations tested (27). 

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. 

McCrary JE, Heagler MG. 1997. The use of a simultaneous multiple species acute toxicity test to compare the relative sensitivities of aquatic organisms to mercury. J Environ Sci Health Part A Environ Sci Eng Toxic Hazardous Substance Control 32 73-81. 

In acute toxicity tests with aquatic organisms, LC50 (96 h) values — with only one exception — exceeded 130 pg/L. The exception was the larva of a marine crab with an LC50 (96 h) value of... 

Toxicity tests are necessary tools to evaluate the concentration and duration of exposure of a chemical required to produce certain adverse effects. Molecular processes directly affected by the exposure to the chemical agent are the most liable criterions. Nevertheless, these effects are difficult to detect in aquatic toxicology because the processes are generally not well understood [72], Alternatively, other end points which fulfil the necessary requirements, namely the need to be unequivocal, relevant, easy to observe, describe and measure, biologically significant and repeatable, are used. These include measures of mortality, which is frequently employed in the early evaluation of the toxicity of a pollutant in acute toxicity tests. This criterion allows comparison of toxicity exerted by chemical agents with very different mechanisms of action. 

AQUATIC EFFECT STUDIES Alga, Growth Inhibition Test Daphnia sp. Acute Immobilisation Test and Reproduction test Fish, AcuteToxIcIty Test PNEC ESTIMATION... 

U.S. Environmental Protection Agency, Committee on Methods for Toxicity Tests with Aquatic Organisms. 1975. Methods for acute toxicity tests with fish, macroinvertebrates, and amphibians. 

CANMET (1996) Comparison of results from alternative acute toxicity tests with rainbow trout for selected mine effluents, Aquatic Effects Technology Evaluation (AETE) Program, Project 1.1.4, Canada Centre for Mineral and Energy Technology (CANMET), Mining Association of Canada (MAC), Ottawa, Ontario, pp. 1-228. 

The index is easily calculated and depends mainly on chronic toxicity tests associated with a sensitive measurement endpoint chosen to be the EC 10 (concentration incurring a 10% effect). It can be used as a regulatory criterion that is more protective of aquatic ecosystems than those based on a single acute toxicity test. 

Four bioassays a) 30 min acute bacterial test (Vibrio fischeri) b) 8d growth rate aquatic plant test (Lemna minor) c) 72h germination plant test (Lepidium sativum) and 8d root elongation plant test (Lepidium sativum) d) 72h germination plant test (Brassica rapa) and 8d root elongation plant test (Brassica rapa) Municipal and industrial solid waste leachates originating from landfills Unspecified pretreatment... 

Maltby et al. (2002) and Van den Brink et al. (2006a) compared SSDs based on acute and chronic laboratory toxicity data for aquatic test species exposed to pesticides. The SSDs were constructed with toxicity data for the most sensitive taxonomic group, because of the specific toxic mode of action of the pesticides selected. The SSDs were used to calculate the hazardous concentration to 5% of the species (HC5) by means of a log-normal distribution model, and comparisons were performed for 2 insecticides and 7 herbicides (Table 6.4). The log-normal model did not fit the diuron (herbicide) short-term L(E)C50 data or the atrazine (herbicide) long-term NOEC data. Consequently, the L(E)C50 HC5 value for diuron and the NOEC HC5 value for atrazine should be interpreted with caution, as well as their acute HC5-chronic... 

Aquatic invertebrate acute toxicity, test, freshwater daphnids... 

There are two basic types of aquatic single-species toxicity tests acute and chronic. Acute toxicity tests have been the workhorse of aquatic toxicologists for many years. These tests are relatively simple, take little time, and are cost-effective. A large historical database exists for many chemicals and effluents. Acute toxicity tests are most often used to quickly screen toxicity or to determine the relative sensitivities of different test species. Mortality is the effect monitored during the test duration of 48 h (invertebrates) or 96 h (fish). In a typical acute toxicity test, 5-10 organisms are exposed under static conditions in glass test beakers to five test concentrations. A control is included. The experiments with test concentrations and control are conducted in triplicate. Daily observations are made on survival, and dead organisms are removed. 

Test data indicates no associated acute aquatic toxicity but may show chronic toxicity. It is reported to be readily biodegradable, but may pose a moderate bioaccumulative risk based on a log Kow value of 5.6. 

Doherty, EG. 1983. Interspecies correlations of acute aquatic median lethal concentration for four standard testing species. Environ. Sci. Technol. 17 661-665. 

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