Sediments river

Sediment Toxicity. Because of their low solubiUty ia water and lipophilic nature, phthalates tend to be found ia sediments. Unfortunately httle work has previously been carried out on the toxicity of phthalates to sediment dwelling organisms. Eor this reason ECPI has commissioned some sediment toxicity studies designed to measure the effect of DEHP and DIDP ia a natural river sediment on the emergence of the larvae of the midge, Chironomus riparius. 

The model is sensitive to lower river sediment oxygen demand. If the demand is removed, the predicted DO value at RK 3.1 (RM 5.0) is 8 percent higher than the standard condition. 

Milliman, J. D. and Meade, R. H. (1983). World-wide delivery of river sediment to the oceans. /. Geol. 91, 1-21. 

Goodbred, S. L., Jr and Kuehl, S. A. (1998). Floodplain process in the Bengal Basin and the storage of Ganges-Brahmaputra River sediment an accretion study using Cs and Pb geochronology. Sediment. Geol. 121,239-258. 

If the sample and standard have essentially the same matrices (e.g., air particulates or river sediments), one can go through the total measurement process with both the sample and the standard in order to (a) check the accuracy of the measurement process used (compare the concentration values obtained for the standard with the certified values) and (b) obtain some confidence about the accuracy of the concentration measurements on the unknown sample since both have gone through the same chemical measurement process (except sample collection). It is not recommended, however, that pure standards be used to standardize the total chemical measurement process for natural matrix type samples chemical concentrations in the natural matrices could be seriously misread, especially since the pure PAH probably would be totally extracted in a given solvent, whereas the PAH in the matrix material probably would not be. All the parameters and matrix effects. Including extraction efficiencies, are carefully checked in the certification process leading to SRM s. 

Thomas, R. R, Ure, A. M., Davidson, C. M., Littlejohn, D., Rauret, G., Rubio, R., and Lopez-Sanchez, J. F., Three-Stage Sequential Extraction Procedure for the Determination of Metal in River Sediments, Analytica Chimica Acta 286, 1994, 423 29. 

Bedard DL, H van Dort, KA Deweerd (1998) Brominated biphenyls prime extensive microbial reductive deha-logenation of Arochlor 1260 in Housatonic River sediment. Appl Environ Microbiol 64 1786-1795. 

DT Lin, CB Morgan, WL Gately (1993) In situ stimulation of aerobic PCB biodegradation in Hudson River sediments. Science 259 503-507. 

A study using resuspended river sediment (Marchesi et al. 1991) illustrated the important interdependence of substrate attachment to particulate matter and its biodegradability. Addition of sodium dodecyl sulfate that is degradable resulted in a relative increase in the number of particle-associated bacteria, whereas this was not observed with the nondegrad-able analogs such as sodium tetradecyl sulfate or sodium dodecane sulfonate. 

Flanagan WP, RJ May (1993) Metabolite detection as evidence for naturally occurring aerobic PCB degradation in Hudson River sediments. Environ Sci Technol 27 2207-2212. 

Ballerstedt H, A Kraus, U Lechner (1997) Reductive dechlorination of 1,2,3,4-tetrachlorodibenzo-p-dioxin and its products by anaerobic mixed cultures from Saale River sediment. Environ Sci Technol 31 1749-1753. 

Harkness MR, JB McDermott, DA Abramowicz, JJ Salvo, WP Flanagan, ML Stephens, FJ Mondello, RJ May, JH Lobos, KM Carroll, Ml Brennan, AA Bracco, KM Fish, GL Warner, PR Wilson, DK Dietrich, DT Lin, CB Morgan, WL Gately (1993) In situ stimulation of aerobic PCB biodegradation in Hudson River sediments. Science 259 503-507. 

Another example which poses many questions is a study of PCBs in river sediment and fish and PCB transport under varying flow conditions. The objectives of the field study were ... 

The As (arsenic) concentration of seawater is controlled by input of rivers, sedimentation on the seafloor, weathering of the seafloor, exchange between atmosphere and seawater, volcanic gas input, and hydrothermal input. Previous studies on the geochemical cycle of As have not taken into account the hydrothermal flux of As. Therefore, hydrothermal flux of As from back-arc, island arc and midoceanic ridges to ocean is considered below. 

Epstein MS, Diamondstone BI, Gills TE (1989) A new river sediment standard reference material. Talanta 36 141-150. 

Tab. 3.5 Certified values for 25 constituent elements in NIST SRM 2704, River sediment...

Multi-method certification of 25 elements with information provided on another 22 elements was performed in NIST SRM 2704 (Buffalo River sediment) by NIST laboratories with four co-operating laboratories from USA and Canada (Epstein et al. 1989). 

Using a newly developed, transversely heated graphite atomizer and D2-back-ground correction (for details see Sections 2.2 and 4.3), Cd, Pb and Cr were determined in cement and river sediment samples. Of the various calibration approaches applied the best results, also in comparison with wet chemical procedures, were achieved with calibration curves constructed by means of different BCR CRMs with different analyte concentrations and usually n = to individual intakes (Nowka and Muller 1997). 

Marine sediments, plant, flesh water lake sediment soil terrestrial plants milk powder Freshwater sediment soil Spruce twigs needles River sediment Coal fly ash... 

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