River sediments Mississippi

Khalid R.A., Gambrell, R.P., Patrick, W.H.Jr., Chemical availability of cadmium in Mississippi River sediment. J Environ Qual 1981 10 523-528. 

Tabor and Barber examined the 2800 km reach of the Mississippi river for the occurrence and fate of LAS in waters and bottom sediments [3], Dissolved LAS was concentrated on reversed-phase (RP)-Cis solid-phase extraction (SPE) cartridges, while sediment-bound LAS was extracted with methanol in three 24-h cycles on a rotating mixer. After derivatisation of the extracts to yield the trifluoroethyl esters, analyses were performed by gas chromatography mass spectrometry (GC-MS). Upon enrichment of 900 mL samples, detection limits of 0.1p.gL 1 were achieved. LAS was identified in 21% of the water samples at concentrations ranging from 0.1 to 28 p,g L-1 and was detected at all of the Mississippi river sediment samples at concentrations ranging from 0.01 to 20 mg kg-1 with a mean value of 0.83 mg kg-1. The concentrations of LAS sorbed onto sediment particles generally did not correlate with... 

River transport of clay minerals into the ocean is spatially and temporally variable. The global annual suspended load of river sediment into coastal waters currently averages 12.6 X 10 ton. This flux is approximately 10% less than was delivered before humans began damming rivers. (One notable exception is the Mississippi River, whose sediment load has increased due to very high rates of soil erosion. The riverine sediments deposited in the mouth of the Mississippi River form one of the world s largest deltas.)... 

Missouri River sediments), 4.95 (Mississippi River sediments), 5.41 (river sediments east of Lorenzo, IL) (Williams et al., 1995)... 

Photolytic. When an aqueous solution of p,//-DDE (0.004 pM) in natural water samples from California and Hawaii were irradiated (maximum X = 240 nm) for 120 h, 62% was photooxidized to jD,p -dichlorobenzophenone (Ross and Crosby, 1985). In an air-saturated distilled water medium irradiated with monochromic light (>. = 313 nm), p,//-DDE degraded to jo,//-dichloro-benzophenone, l,l-bis(p-chlorophenyl)-2-chloroethylene (DDMU), and l-(4-chlorophenyl)-l-(2,4-dichlorophenyl)-2-chloroethylene (o-chloro DDMU). Identical photoproducts were also observed using tap water containing Mississippi River sediments (Miller and Zepp, 1979). The photolysis half-life under sunlight irradiation was reported to be 1.5 d (Mansour et al., 1989). 

Mississippi sediment), 4.98 (Ohio River sediment) (Karickhoff and Morris, 1985)... 

Fisk, H.N. (1960) Recent Mississippi River sedimentation and peat accumulation. Compte Rendu 4th Congres 1 Avancement des Etudes de Stratigraphie et de Geologie du Carbonifere, Heerlen 1958, 1 187-199. 

FIGURE 10.14 Water-soluble iron accumulation in Mississippi River sediments incubated at a range of pH and Eh levels. (From Gambrell et al., 1975.)... 

A study was conducted on Mississippi River sediment material under conditions of controlled pH (5.0, 6.5, and 8.0) and redox potential (-150, 50, 250, and 500 mV) to determine the effect of these parameters on chemical forms and distribution of added zinc. The results of this study indicate that adsorption by or coprecipitation with oxides and hydroxides of iron and manganese was the important regulatory process governing the availability of zinc in this sediment-water system. 

The Effect of pH and Redox Potential on the Chemical Form and Distribution of Added Zinc in Mississippi River Sediment Suspensions... 

FIGURE 12.17 Effects of pH and redox potential on total water-soluble cadmium in Mississippi River sediment suspensions measured by flameless atomic absorption. (From Khalid, R. A., Gambrell, R. R, and Patrick, W. H., Jr., J. Environ. Qual. 10, 523, 1981.)... 

Subsidence due to compaction of the Mississippi River sediment accounts for 85-95% of the water-level increase. During the past several thousand years, the Mississippi River deltaic plain expanded considerably, despite the rapid increase in relative sea-level rise. However, in the last century, this accretion trend was reversed with wetland losses of up to 100 km year". As a result, marsh... 

Khalid, R. A., R. P. Gambrell, and W. H. Patrick, Jr. 1978. Chemical transformations of cadmium and zinc in Mississippi River sediments as influenced by pH and redox potential. In D. C. Adriano and I. L. Brisbin, Jr. (eds.) Environmental Chemistry and Cycling Processes. Department of Energy, Symp. Ser. 45 417-433. Tech. Info. Center, U.S. Department of Energy. Proc. 2nd Mineral Cycling Symp., May 1, 1976. 

A study of mercury sorption by Mississippi River sediments conducted Khalid, et al. (1975) found a strong correlation between mercury sorption, pH, Eh and total mercury availability. They found maximum adsorption occurred under strongly reducing conditions desorption was found to increase with increased oxidation and, in general, retention was favored under reduced, alkaline conditions. 

Khalid, R.A., R.P. Gambull, W.H. Patrick, Jr., 1975, Sorption and Release of Mercury by Mississippi River Sediment as Affected by pH and Redox Potentieil, ERDA Symposium on Biological Implications of Metals in the Environment, pp. 297-314. 

Storm surges powered by tropical storms and hurricanes can wreak havoc along low-lying coasts. The settlers who founded New Orleans in 1718 along the lower Mississippi River experienced their first major flood the same year. Over time, many other floods have occurred in New Orleans and the lower reaches of the Mississippi, aided by the slow sinking of the floodplain as river sediments compact over time. 

Balogh SJ, Engstrom DR, Ahnendinger JE, Meyer ML, Johnson DK. 1999. A history of mercury loading in the upper Mississippi River reconstructed from the sediments of Lake Pepin. Environ Sci Technol 33 3297-3302. 

Atchafalaya and Mississippi Rivers. Florida Bay waters, which overlie U-rich sediments, contain much higher ( Ra/ " Ra) activity ratios than other estuaries. The increased ( Ra/ " Ra) values observed at high salinities in the Mississippi/Atchafalaya systems indicate preferential decay of the shorter-lived ""Ra over Ra during estuarine mixing. 

The 5,330 hectare (13,170 acre) Savanna Army Depot Activity, north of Savanna, IL, consists of high ground and Mississippi River flood plain. In the flood plain are 223 hectares of waterways connected to the river about 10 hectares of sediment plain in these waterways are considered potentially contaminated by munitions-related compounds (see Table I). Of these compounds, only TNT has been isolated (0.3 rag/kg in one sediment sample) DNT, TNB, and RDX are associated with TNT in other munitions contexts, hence they were also included. The waterways are fished by a number of activity personnel and retirees. These persons and their families may eat some of their catch, and thereby ingest those compounds that might be present in the fish (predominantly carp and catfish, both bottom-feeders). Acceptable safe sediment level guidance for these compounds was therefore desired. 

Beauvais, S.L., J.G. Wiener, and G.J. Atchison. 1995. Cadmium and mercury in sediment and burrowing mayfly nymphs (Hexagenia) in the upper Mississippi River, USA. Arch. Environ. Contam. Toxicol. 28 178-183. 

In general, silver concentrations in surface waters of the United States decreased between 1970-74 and 1975-79, although concentrations increased in the north Atlantic, Southeast, and lower Mississippi basins (USPHS 1990). About 30 to 70% of the silver in surface waters may be ascribed to suspended particles (Smith and Carson 1977), depending on water hardness or salinity. For example, sediments added to solutions containing 2 pg Ag/L had 74.9 mg Ag/kg DW sediment after 24 h in freshwater, 14.2 mg/kg DW at 1.5% salinity and 6.9 mg/kg DW at 2.3% salinity (Sanders and Abbe 1987). Riverine transport of silver to the ocean is considerable suspended materials in the Susquehanna River, Pennsylvania — that contained as much as 25 mg silver/kg — resulted in an estimated transport of 4.5 metric tons of silver to the ocean each year (USEPA 1980). The most recent measurements of silver in rivers, lakes, and estuaries using clean techniques show levels of about 0.01 pg/L for pristine, nonpolluted areas and 0.01 to 0.1 pg/L in urban and industrialized areas (Ratte 1999). 

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