Accumulation factor

Heavy metals. The profiles of sediment and pollutant depositions and the relationships of concentrations with time have been reconstructed. For most metals the highest accumulations took place between the fifties and the sixties, when the fastest industrial development of Porto Marghera took place. In Figure 2 the concentration profiles of three of the most interesting metals (Hg, Pb, Cd) are plotted vs. depth. Data were "normalized" (i.e. divided) by the background levels, as metals have different natural presence in the environment. This leads to accumulation factors, referred to pre-industrial background values. Any derived data tell... 

Thomann RV, Mahoney JD, Mueller R. 1995. Steady-state model of biota sediment accumulation factor for metals in two marine bivalves. Environ Toxicol Chem 14 1989-1998. 

Olgutn, E.J., Vidal, M., Sanchez-Galvan, G., and Houbron, E., Bioadsorption and intracellular accumulation factors of lead in constructed wetlands microcosms with Salvinia minima operating continuously The effect of light intensity, International Symposium on Biotechnology, Dalian, China, October 12-17,... 

Sanchez-Galvan, G., Monroy, O., G6mez, J., and Olguln, E.J., Assessment of the hyperaccumulating lead capacity of Salvinia minima using bioadsorption and intracellular accumulation factors, Water, Air, and Soil Pollution, 194, 77-90, 2008. 

Two species of freshwater aquatic mosses (Fontinalis dalecarlica, Platyhypnidium riparoides) exposed to concentrations between 0.5 and 6.5 pg Cd/L for 28 days had accumulation factors as high as 137,000 and 158,000, respectively (Gagnon etal. 1998). Accumulations increased with increasing cadmium concentration and decreasing water hardness. Cadmium tended to persist in these mosses. During a depuration period of 28 days following the 28-day exposure, only 37 to 48% of the accumulated cadmium was eliminated (Gagnon et al. 1998). 

The progressive increase of chemical and/or metabolites in the body. Accumulation is influenced by the dosing interval and half-life of the chemical. The process can be characterized by an accumulation factor, which is the ratio of the plasma concentration at steady state to that following the first dose in a multiple dosing regimen. 

The following shows the development of the predictive QSPR model. The descriptors considered for the model include geometric and topological descriptors, electronic properties, charge-dependent properties, physico-chemical properties, and accumulation factors. The solid phases studied include three soil types (mollisol, ultisol, and aridisol) and two aquatic sediments. 

Sugiura, K.. Washino, T., Hattori, M., Sato. E.,and Goto. M. Accumulation oforganochlorine compounds in fishes. Difference of accumulation factors by fishes, Chemosphere, 8(6) 359-364,1979. 

In another study conducted in river waters and sediments of central Italy, a direct relationship between PAEs concentration levels in water samples fi om rivers and lakes with input of urban or industrial treated wastewaters near the sampling point were also found [82]. They also found an accumulation factor in sediment samples ranging from 10 to 100, showing the trend of PAEs to be absorbed in sediments. DEHP and DBP were found in higher concentration levels than the other seven PAEs investigated. The presence of PAEs in the studied fi eshwaters was closely related to the input of urban and industrial treated wastewaters. DEPH concentrations in freshwater and sediment samples ranged from 0.3 to 31.2 pg/L and from 0.003 to 0.49 pg/g, respectively. 

Huang P-C, Tien C-J, Sun Y-M, Hsieh C-Y, Lee C-C (2008) Occurrence of phthalates in sediment and biota relationship to aquatic factors and the biota-sediment accumulation factor. Chemosphere 73 539-544... 

Figure 12.5. Uptake of I-Suc-HSA in liver slices from humans and rats at 37°(0) and 4°C ( ). The accumulation factor is defined as the concentration of the compound in the slices divided hy the concentration in the medium. Each point is the mean of 5-6 separate experiments SEM. n = number of livers. p < 0.05 versus 4°C. The dotted line represents the accumulation factor if I-Suc-HSA is exclusively distrihuted within the sinusoids.

TABLE II. Sediment Accumulation Factors for Some of the Anthropogenic Compounds from the Plant. 

Compound (see Fig. 2) Wastewaster River Water Sediment Accumulation Factor... 

Tab. 16.5 Correlation coefficients with Fe and accumulation factors with respect to parent rock...

Element Laterites from basalts (n SI) Accumulation factor with respect to parent rock Lateritic soils of Western Australia (n 39) Range of Correlation coefficient with concentration Fe concentration ... 

BCF Bio concentration Factor sediment-to-fish has accumulation factor 4 NOEC biota to construct SSD in Figure 5... 

Accumulation is inversely proportional to the fraction of the dose lost in each dosing interval. The fraction lost is 1 minus the fraction remaining just before the next dose. The fraction remaining can be predicted from the dosing interval and the half-life. A convenient index of accumulation is the accumulation factor ... 

For a drug given once every half-life, the accumulation factor is 1/0.5, or 2. The accumulation factor predicts the ratio of the steady-state concentration to that seen at the same time following the first dose. Thus, the peak concentrations after intermittent doses at steady state will be equal to the peak concentration after the first dose multiplied by the accumulation factor. 

Estimates of dosing rate and average steady-state concentrations, which may be calculated using clearance, are independent of any specific pharmacokinetic model. In contrast, the determination of maximum and minimum steady-state concentrations requires further assumptions about the pharmacokinetic model. The accumulation factor (equation... 

Figure 4. Comparative accumulation of actinides by small mammals from contaminated soil or sediment relative to the accumulation of plutonium-239. Accumulation factor (AF) = concentration of nuclide in the internal small mammal body -- concentration of nuclide in dry soil. Twelve shrews and seven rats and mice from a floodplain forest were composited to yield four and three separate analyses, respectively. Twelve cotton rats inhabiting the banks of a liquid waste pond (3513) also were analyzed.

Evaluating Bioaccumulation Disequilibrium - Example Biota-Sediment Accumulation Factors... 

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

Why do biomagnification and biota-sediment-accumulation factors of persistent chemicals in aquatic systems tend to increase with increasing hydrophobicity of the compounds ... 

Calculate the lipid- and organic carbon-normalized biota-soil accumulation factors (BASFlhpac) for the two compounds and soils. Compare these values with estimated equilibrium accumulation factors (Kmpoc). All necessary data can be found in Appendix C. Discuss why the resulting BASFt and Kt values differ. 

Tracey, G. A., and D. J. Hansen, Use of biota-sediment accumulation factors to assess similarity of nonionic organic chemical exposure to benthically coupled organisms of differing trophic mode , Environ. Toxicol. Chem., 30, 467-476 (1996). 

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