Sediment inventories

Lager, n. bed, layer, stratum store, stock storehouse sediment, deposit camp bed, couch lair stand (for casks) Mach.) bearing, biish. -bestand, m. stock, inventory. 

The short4ived particle reactive radionuclides of the U/Th series also have enormous potential for tracking particle source and transport in ocean margins. Mass balances comparing inventories in sediments with supply can be used to determine import or export of particles to an area. Such approaches are increasingly important in understanding the fates of particle-reactive contaminants whose sources are often enhanced in the coastal ocean. Studies of especially when supplemented by other... 

The Level II calculations at pH 5.1 include the reaction half-lives of 550 h in air, 550 h in water, 1700 h in soil and 5500 h in sediment. No reaction is included for suspended sediment or fish. The steady-state input of 1000 kg/h results in an overall fugacity of 3.43 x 1(H Pa, which is about 24 times the Level I value. The concentrations and amounts in each medium are thus about 24 times the Level I values. The relative mass distribution is identical to Level I. The primary loss mechanism is reaction in soil, which accounts for 936 kg/h, or 94% of the input. Most of the remainder is lost by reaction and advection in water. The air and sediment loss processes are unimportant largely because so little of the PCP is present in these media. The overall residence time is 2373 h thus, there is an inventory of PCP in the system of 2373 x 1000 or 2,373,000 kg. 

The 210Pb inventory in the sediments was calculated in a similar way to the 239,240pu method described previously, but 1 cm increments were used in determining the integrated deposition. The deposition rate of the 210Pb for each core was determined as the product of the integrated deposition and the radioactive decay constant, (A. =. 0311 yr-1). Since the unsupported 210Pb (t ... 

By combining the findings of Cacchione, Drake and the results reported here, a coherent model can be proposed to explain the deposition inventory of the radionuclides. The down-canyon current transports large quantities of sediment toward the radioactive waste disposal site at 4000 m. Within the upper canyon, fine material is transported the furthest. Near the mouth of the canyon, sediment erosion of the walls occurs due to the down-canyon currents meeting a proposed opposing on-shore bottom current. The eroded material from the walls is transported and the finer material is deposited in eddies formed where the two currents meet. 

Much of the mercury that enters freshwater lakes is deposited in bottom sediments (Rada et al. 1993). Sedimentary pools of mercury in these lakes greatly exceed the inventories of mercury in... 

Kennicutt MC, Wade BJ, Presley AG, et al. 1994. Sediment contaminants in Casco Bay, Maine Inventories, sources, and potential for biological impact. Environ Sci Technol 28(1) 1-15. 

In a batch sedimentation experiment, the sediment builds up gradually and the solids which are deposited in the early stages are those which are subjected to the compressive forces for the longest period of time. In the continuous thickener, on the other hand, all of the particles are retained for the same length of time with fresh particles continuously being deposited at the top of the sediment and others being removed at the same rate in the underflow, with the inventory thus remaining constant. Residence time distributions are therefore not the same in batch and continuous systems. Therefore, the value of tR calculated from equation 5.59 will be subject to some inaccuracy because of the mismatch between the models for batch and continuous operation. 

Table 22.3 Inventory of Presently Known Blomacromolecules, Their Ooourrence In Extant Organisms, and Their Potential for Survival During Sedimentation and Diagenesis. ...

The oceanic carbon inventory was presented in Table 15.3. Most of the carbon is inorganic (98%), predominantly in the form of bicarbonate (87%), and is located in the intermediate and deep waters. Of the 2% that is organic, the majority is DOC (see Table 23.2). At present, the ocean is acting as a net sink for atmospheric CO2. In the modern-day carbon cycle, the sole oceanic sink fitr carbon is burial in the sediments in the form of detrital biogenic PIC and POC. 

National Water Quality Inventory found that more than 30 percent of the rivers and streams studied and more than 20 percent of the lakes studied had to be classified as "impaired because of sedimentation problems. 

Table 1 Published sediment inventories of PCBs in the Great Lakes...

We should keep in mind that the Hyde Park landfill site, sitting in fractured bedrock only 0.6 km from the Niagara River gorge, is widely reported to contain in the order of 1000 kg of 2378-TeCDD, although an authoritative confirmation of this information was not found. If true, this is a great deal more than has already been flushed into Lake Ontario, considering that 2378-TeCDD is a small percentage of the inventory of 5800 kg total PCDD/Fs in Lake Ontario sediments. 

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