Comparative accumulation

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.

Alquezar, R., S.J. Markich, and J.R. Twining. 2008. Comparative accumulation of 109Cd and 75Se from water and food by an estuarine fish (Tetractenos glaber). J. Environ. Radioact. 99 167-180. 

Rainbow PS and White SL (1990) Comparative accumulation of cobalt by three crustaceans a decapod, an amphipod and a barnacle. Aquat Toxicol 16 113-126. 

In an additional study, Freitas (1995) analyzed the comparative accumulation of Cr, Fe, Co, Zn, Se, Sb and Hg in two vascular plants, Cistus salvifolius and Inula viscosa and in the epiphytic lichen Parmelia sulcata in an industrial region occupied by a thermal coal-fired power station, a chemical plant and an oil refinery. Of the three organisms, the lichen P. sulcata was found to be the most effective bioaccumulator, as the above-mentioned elements accumulated in large amounts in the lichen. Thus, P. sulcata was recommended as a reliable bioindicator of air pollution. 

McLeese DW, Burridge LE( 1987) Comparative accumulation ofPAHs in four marine invertebrates. In Capuzzo JM, Kester DR (eds) Oceanic processes in marine pollution, Vol 1. Biological processes and wastes in the ocean. Krieger, Malabar, Florida, pp 109-117... 

Figure 11. (below) Proposal for a Farmer Matrix for comparing accumulated risk estimates. 

Some of the observed patterns of accumulation of PAHs from laboratory and field studies may be explained by the rates of uptake and elimination. These rates can be affected by several environmental and physiological factors hence, care must be taken to define the conditions under which bioaccumulation is observed. A laboratory investigation that compared accumulation of PAHs in oysters Crassostrea virginica) and clams Mercen-aria mercenaria) from field-contaminated sediments found that the oyster accumulated about three times as much PAH as the clam (Bender et al. 1988). For most individual PAHs, the ratios between oyster and clam tissue concentrations were between 1 and 5. The authors found no species differences in uptake clearance k and concluded that the differences in equilibrium BCF values resulted from the higher elimination rate k in the clam for most PAHs, which would lead to lower body burdens for a given... 

The EU contains capacitor battery (CB), current source (CS), accumulator (Ac), controlled by CS, impulse former (IF),power supply (PS), two comparators (Cpl,Cp2),... 

In order to compare the efficiency of the SISM with the standard LFV method, we compared computational performance for the same level of accuracy. To study the error accumulation and numerical stability we monitored the error in total energy, AE, defined as... 

CAUTION. Ethers that have been stored for long periods, particularly in partly-filled bottles, frequently contain small quantities of highly explosive peroxides. The presence of peroxides may be detected either by the per-chromic acid test of qualitative inorganic analysis (addition of an acidified solution of potassium dichromate) or by the liberation of iodine from acidified potassium iodide solution (compare Section 11,47,7). The peroxides are nonvolatile and may accumulate in the flask during the distillation of the ether the residue is explosive and may detonate, when distilled, with sufficient violence to shatter the apparatus and cause serious personal injury. If peroxides are found, they must first be removed by treatment with acidified ferrous sulphate solution (Section 11,47,7) or with sodium sulphite solution or with stannous chloride solution (Section VI, 12). The common extraction solvents diethyl ether and di-tso-propyl ether are particularly prone to the formation of peroxides. 

Dry Foods. Dry foods are concentrated sources of nutrition and provide the most economical nutritional value because water in canned foods is expensive. Dry foods tend to scrape the teeth as pets eat, minimizing tartar deposition. When dry food is moistened prior to being consumed, tartar accumulates in a manner comparable to deposits observed with caimed foods. Approximately 95 to 98% of dry-type cat and dog foods are made by the extmsion process the remainder is made by pelleting or baking. 

Some nut trees accumulate mineral elements. Hickory nut is notable as an accumulator of aluminum compounds (30) the ash of its leaves contains up to 37.5% of AI2O2, compared with only 0.032% of aluminum oxide in the ash of the Fnglish walnut s autumn leaves. As an accumulator of rare-earth elements, hickory greatly exceeds all other plants their leaves show up to 2296 ppm of rare earths (scandium, yttrium, lanthanum, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium). The amounts of rare-earth elements found in parts of the hickory nut are kernels, at 5 ppm shells, at 7 ppm and shucks, at 17 ppm. The kernel of the Bra2d nut contains large amounts of barium in an insoluble form when the nut is eaten, barium dissolves in the hydrochloric acid of the stomach. 

Available Chlorine Test. The chlorine germicidal equivalent concentration test is a practical-type test. It is called a capacity test. Under practical conditions of use, a container of disinfectant might receive many soiled, contaminated instniments or other items to be disinfected. Eventually, the capacity of the disinfectant to serve its function would be overloaded due to reaction with the accumulated organic matter and organisms. The chlorine germicidal equivalent concentration test compares the load of a culture of bacteria that a concentration of a disinfectant will absorb and still kill bacteria, as compared to standard concentrations of sodium hypochlorite tested similarly. In the test, 10 successive additions of the test culture are added to each of 3 concentrations of the hypochlorite. One min after each addition a sample is transferred to the subculture medium and the next addition is made 1.5 min after the previous one. The disinfectant is then evaluated in a manner similar to the phenol coefficient test. For equivalence, the disinfectant must yield the same number of negative tubes as one of the chlorine standards. 

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