Acute aquatic toxicity

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. 

Phosphonates are often used in detergents as stabilizers for encymes and bleaching components in a concentration of <0.5%. Dates of acute aquatic toxicity of the most used substances HEDP, aminotrismethylenephosphonic acid (ATMP), and EDTMP are given in Table 14. In a concentration of <2 mg/L no remobilization of heavy metals from sediments was observed [207]. 

The Research Institute on Fragrance Materials maintains the most comprehensive worldwide source database on fragrance/flavour components including acute aquatic toxicity, biodegradation data, human health issues, for example, carcinogenesis, sensitization. A password is required to access the database. 

Figure 11. Acute aquatic toxicities (% effluent) of biotreated effluents to fathead minnow.

Table 13.1 Example of two chemicals with similar predicted properties [octanol-water partition coefficient (logPQ/w) and lowest unoccupied molecular orbital (LUMO) energy] and similar acute aquatic toxicity (LC50) values to the fathead minnow [6].

In some cases, physical and chemical properties are highly predictive of toxicity. A good example is acute aquatic toxicity, which is discussed in detail later in this chapter. However, some biological interactions that lead to toxicity, such as receptor binding, are highly specific and in those cases it is less likely that straightforward relationships between properties and toxicity can be found. A common example is the difference in toxicity of two enantiomers, such as the R- and S-enantiomers of thalidomide. 

Using Property Guidelines to Design for Reducing Acute Aquatic Toxicity... 

Figure 13.7 Box plots of logPo/w and AE (HOMO - LUMO) by EPA level of concern for acute aquatic toxicity (High, Medium, Low, None) and by species. Box plot widths are proportional to the square root of the counts in...

Figure 13.8 Scatter plot of logPo/w and AE (HOMO - LU MO) energy (eV) for acute aquatic toxicity for combined data for fathead minnow (96 h), Japanese medaka (96 h) and Daphnia...

The physicochemical properties listed in Table 13.4 are known to favor reduced acute aquatic toxicity. Meeting just one of these design criteria is often not sufficient to make a chemical significantly less likely to be toxic however, as has been shown in the recent literature, meeting two or three is. 

Octanol-water partition coefficient (logP0/w) lipophilicity (logPo/w) usually correlates well with acute aquatic toxicity. For nonionic organic chemicals that are toxic through narcosis, acute and chronic toxicity increases exponentially with increases in logPo/w up to a value of about 5-7. For those with logPo/w >5, bioavailability decreases along with toxicity, but bioaccumulation also increases. Minimal toxicity is likely for chemicals with log/ ( w <2 [32]... 

Svenson, A. and Zhang, L. (1995) Acute aquatic toxicity of protolyzing substances studied as the Microtox effect, Ecotoxicology and Environmental Safety 30 (3), 283-288. 

Hockett, J.R. and Mount, D.R. (1996) Use of metal chelating agents to differentiate among sources of acute aquatic toxicity, Environmental Toxicology and Chemistry 15, 1687-1693. 

Prediction of acute aquatic toxicity Specific toxicity... 

Also important to the validation process of QSARs is vertical validation. In this instance, quantitatively similar QSARs are developed with similar descriptors but using data for a different toxic endpoint. For example, the investigation of Karabunarliev et al. (1996b) modeled acute aquatic toxicity data for the fathead minnow Pimephales promelas. The compounds considered in the analysis were confined to substituted benzenes, and descriptors limited to log Kow and Amjx. The fish toxicity QSAR (log [LQ,]-1 = 0.62 log K, + 9.17 A - 3.21 n = 122 R2 = 0.83 i = 0.16 F = 292) of Karabunarliev et al. (1996b) was very similar in terms of slope, intercept, and statistical fit to the QSAR presented in Equation 12.2. The fact that different endpoints provide very similar QSARs indicates that the QSAR is valid across protocols. This shows the universality of the model. 

It can be imagined that a QSAR for acute aquatic toxicity was selected by an independent body during a literature review of available QSARs, including the final report of a Directorate General (DG) Research Project (European Economic Community, 1995). In particular, the following QSAR for predicting the acute toxicity of organic chemicals to the fathead minnow (Pimephales promelas) was reported ... 

Legierse KCHM, Verhaar HJM, Vaes WHJ, De Bruijn JHM, Hermens JLM. 1999. Analysis of the time-dependent acute aquatic toxicity of organophosphorus pesticides the critical target occupation model. Environ Sci Technol 33 917-925. 

The cut-off values for classification of mixtures are normally specified by concentrations expressed as % of the component substance. In some cases, for example acute toxicity (human health), the cut-off values are expressed as acute toxicity values (ATE). The classification of a mixture is determined by additivity calculation based on acute toxicity values (see Chapter 3.1) and concentrations of component substances. Similarly acute aquatic toxicity classification may be calculated on the basis of acute aquatic toxicity values (see Chapter 4.10) and where appropriate, corrosion/irritation by adding up concentrations of individual substances (see Chapters 3.2 and 3.3). Component substances are taken into consideration for application of the formula when the concentration is equal to or greater than 1 %. Some competent authorities (CA) may use this cut-off as a basis of obligation to compile an SDS. 

Acute aquatic toxicity means the intrinsic property of a substance to be injurious to an organism in a short-term exposure to that substance. 

A9.6.4.7 The Nordic Council of Ministers issued a report (Pederson et al, 1995) entitled Environmental Hazard Classification, that includes information on data collection and interpretation, as well as a section (5.2.8) entitled QSAR estimates of water solubility and acute aquatic toxicity . This section also discusses the estimation of physicochemical properties, including log Kow For the sake of classification purposes, estimation methods are recommended for prediction of minimum acute aquatic toxicity, for ...neutral, organic, non-reactive and non-ionizable compounds such as alcohols, ketones, ethers, alkyl, and aryl halides, and can also be used for aromatic hydrocarbons, halogenated aromatic and aliphatic hydrocarbons as well as sulphides and disulphides, as cited in an earlier OECD Guidance Document (OECD, 1995). The Nordic document also includes diskettes for a computerized application of some of these methods. 

A9.6.4.12 Acute aquatic toxicity for fish, daphnia and algae... 

Acute aquatic toxicity was determined on both Daphnia magna and rainbow trout (25). The Daphnia magna became trapped in oil sheen and the concentration that produced 50% death was determined to be 99 ppm (compared with table salt at 3.7 ppm and diesel at 1.4 ppm). 

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. 

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