Bioaccumulation Parameters

Fisk, A.T., R.J. Norstrom, C.D. Cymbalisty, and D.C.G. Muir. 1998. Dietary accumulation and depuration of hydrophobic organochlorines bioaccumulation parameters and their relationship with the octanol/water partition coefficient. Environ. Toxicol. Chem. 17 951-961. 

Fisk, A T., Bosenberg, B., Cymbalisty, C.D, Stem, G.A., Muir, D.C.G. (1999) Octanol/water partition coefficients of toxaphene congeners determined by the slow-stirring method. Chemosphere 39, 2549-2562 Fisk, AT., Norstrom, R.J., Cymbalisty, C.D, Muir, D.C.G. (1998) Dietary accumulation and depuration of hydrophobic oiganochlo-rines bioaccumulation parameters and their relationship with the octanol/water partition coefficient. Environ. Toxicol. Chem. 17, 951-961. 

Law, K. Palace, V.P HaUdorson, T. DaneU, R. Wautier, K. Evans, B. Alaee, M. Marvin, C. Tomy, G.T., Dietary accumulation of hexabromocyclododecane diastereoisomers in juvenile rainbow trout Onocrhynchm mykiss) I Bioaccumulation parameters and evidence of bioisomerization Environ. Toxicol Chem. 2006, 25, 1757-1761. 

For a number of organic compounds, such as DDT, polychlorinated benzenes (PCBzs), biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and naphthalenes (PCNs), relationships between physical-chemical, physiological and bioaccumulation parameters have been established [18, 37, 41-43], which will be evaluated in the following sections. 

Equations (20) - (23) include bio accumulation kinetics, and thus enable us to predict when organisms will attain lethal body burdens. The most important bioaccumulation parameters, and the relationships between the bioaccumulation parameters and physical-chemical and physiological factors, which are required can either be found in the literature or need to be studied. The equations can thus be used to predict if organisms are at risk and will experience adverse effect at a given external exposure concentration. Time will thus be a variable, whereas the external exposure concentration in either water or food will be the given input parameters in this exercise. The equations can also be used to estimate the external concentration which will lead to adverse effects at a given exposure time. Then, external exposure concentration will be a variable, whereas the time required for eliciting effects will be a constant. 

Contents indude modeling accumulation and toxidty of organic chemicals in aquatic food chains and food webs, derivation of bioaccumulation parameters, and application of food chain models for dioxins and furans. 

Bioaccumulation is generally referred to as a process in which the chemical concentration in an organism achieves a level that exceeds that in the respiratory medium (e.g., water for a fish or air for a mammal), the diet, or both. The extent to which chemicals bioaccumulate is expressed by several quantities, including the bioconcentration factor (BCF), bioaccumulation factor (BAF), biomagnification factor (BMF), and trophic or food web magnification factor (TMF) [6]. The ecological, biological and chemical parameters involved in the transfer and accumulation of contaminants in food webs are complex. 

The partition coefficient Kq of an organic compound in the 1-octanol/water system is used to assess the bioaccumulation potential and the distribution pattern of drugs and pollutants. The partition coefficient of imidazole and ILs strongly depends on the hydrogen bond formed by these molecules and is less than one due to the high solubility in water. The low value of the 1-octanol/water partition coefficient is required for new substances, solvents, insecticides to avoid bioaccumulation. Kqw is an extremely important quantity because it is the basis of correlations to calculate bioaccumulation, toxicity, and sorption to soils and sediments. Computing the activity of a chemical in human, fish, or animal lipid, which is where pollutants that are hydrophobic will appear, is a difficult task. Thus, it is simpler to measure the 1-octanol/water partition coefficient. This parameter is used as the primary parameter characterizing hydrophobisity. 

Parameters Used to Describe Experimental Bioaccumulation Data... 

Figure 10.5 Terms and parameters frequently used to describe accumulation of chemicals in aquatic organisms. Note that the term bioaccumulation (BAF,) is used to describe the total accumulation by all possible routes (e.g., passive uptake, intake by food and digestion, etc.). The term bioconcentration is sometimes...

Describe in words, the parameters (1) bioconcentration factor, (2) biomagnification factor, (3) biota-sediment- and biota-soil- accumulation factor, and (4) bioaccumulation factor. 

Chemical reactivity and biological activity can be related to molecular structure and physicochemical properties. QSAR models can be established among hydrophobic-lipophilic, electronic, and steric properties, between quantum-mechanics-related parameters and toxicity and between environmental fate parameters such as sorption and tendency for bioaccumulation. The main objective of a QSAR study is to develop quantitative relationships between given properties of a set of chemicals and their molecular descriptors. To develop a valid QSAR model, the following steps are essential ... 

A recent workshop (Swanson and Socha 1997) identified more than 100 such systems and subjected 51 of these to a comparative analysis. That analysis identified at least 12 different endpoints for persistence, 15 endpoints for mobility, partitioning, or bioaccumulation, and 34 kinds of data used to estimate exposure. It is axiomatic that the required input data simply are not available for all of the parameters and chemical substances of potential interest. 

Model Equation, Parameters, and their Units of the Zooplankton Bioaccumulation Model of Thomann et al. (1992)... 

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