Bioassay aquatic

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). 

McCarty L.S., Mackay, D., Smith, A.D., Ozburn, G.W. and Dixon, G.D. (1992) Residue-based interpretation of toxicity and bioconcentration QSARs from aquatic bioassays neutral narcotic organic. Environ Toxicol Chem, 11, 917— 930. 

McCarty, P. L., D. Mackay, A. D. Smith, G. W. Ozbum, and D. G. Dixon, Residue-based interpretation of toxicity and bioconcentration QSARs from aquatic bioassays. Neutral narcotic organics , Environ. Toxicol. Chem., 11, 917-930 (1992). 

Main categories of aquatic bioassay applications based on representative publications involving toxicity testing... 

As stated by Johnson (1993), "hazardous waste becomes a problem when it moves", Because water is the main vector for transporting pollutants from wastes towards receiving ecosystems, WASTOXHAS, presented hereinafter, is only focused on ecotoxicological assessment of different leachates with aquatic bioassays. 

Simulation leaching tests are upward-flow (NEN, 7343, 1995) and downward-flow column leaching tests (Huang et al., 2003). Laboratory leachates are collected on a regular basis, chemically monitored and tested with (at least) two aquatic bioassays (see below). 

Test battery approach - At least 2 relevant aquatic bioassays... 

Hazardous waste aquatic bioassay CCR Title 22 100 ml HDPE or glass 32 ml 2 to 6°C Not specified... 

The lipid content of the organism is a critical controlling factor of body residues of organic chemicals. Bio concentration studies often provide lipid-corrected results to compensate for this. Therefore, the lipid content of organisms used in bioassays should be reported routinely in all aquatic bioassays, such as bio concentration, bio accumulation, biomagnification, and toxicity studies with organic chemicals. 

This variability is not unique to biological testing and is well understood in many industrial activities and chemical analyses. Indeed, substantial resources are devoted to measuring and controlling variability in outputs in these sectors. However, the same cannot be said of toxicity testing. In the following sections we consider why variability in aquatic bioassays is important and what can be done to constrain it within reasonable bounds. 

Aquatic bioassays made with elutriates from polymeric materials are possible, although limited to water-soluble components. The elutrition procedure should be designed properly to simulate the conditions of the natural environment of the application. Examples could be the continuous elutrition in aquatic environments or a periodic exposure at times of rainfall in terrestrial environments. However, neither a standardised nor an otherwise validated method is currently available for such investigations. 

McCarty LS (1991) Toxicant body residues implications for aquatic bioassays with some organic chemicals. In Mayes MA, Barron MG (eds) Aquatic Toxicology and Risk Assessment, vol 14. ASTM STP 1124, American Society for Testing and Materials, Philadelphia, PA, pp 183-192. 

Methods. As discussed in the previous chapter, a number of approaches have been used to assess the presence of potentially toxic trace elements in water. The approaches used in this assessment include comparative media evaluation, a human health and aquatic life guidelines assessment, a mass balance evaluation, probability plots, and toxicity bioassays. Concentrations of trace elements were determined by atomic absorption spectrometry according to standard methods (21,22) by the Oregon State Department of Environmental Quality and the U.S. Geological Survey. 

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. 

Stauber JL, Davies CM (2000) Use and limitations of microbial bioassays for assessing copper bioavailability in the aquatic environment. Environ Rev 8 255-301... 

The objective of the research reported here was to develop sensitive bioassays which utilize near-whole plant systems of appropriate target aquatic weeds and which require little space and low volumes of incubation medium. Such bioassays could be used to help identify active fractions of chromatographically partitioned allelochemicals and could also be used in prinary screening procedures for newly synthesized agrichemicals. 

Seeds of lettuce and other species have frequently been used to bioassay for the allelopathic activity of plant exudates (17.18.19). As with the use of cell suspensions, there are certain advantages and disadvantages to this methodology. The experimental simplicity, small amounts of material required and short time frame are certainly attractive qualities. However, species used in such bioassays quite often do not represent the actual target species under consideration. This is especially true when terrestrial crop species are substituted for weeds of aquatic systems. Nevertheless, information obtained from such experiments are often valuable when used in conjunction with results of other assays. 

Damasio J, Tauler R, Teixido E, Rieradevall M, Prat N, Riva MC, Soares AMVM, Barata C (2008) Combined use of Daphnia magna in situ bioassays, biomarkers and biological indices to diagnose and identify environmental pressures on invertebrate communities in two Mediterranean urbanized and industrialized rivers (NE Spain). Aquat Toxicol 87 (4) 310-320... 

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