Nitrate in rivers

Block diagram of a remote spectrophotometric, flow injection based monitor for the determination of nitrate in river water. Reduction to nitrate by copperized cadmium followed by colour development with sulphanilimide and N-I-naphthylmethylenediamine dihydrochloride. 

Content of nitrates in river water (t/km3) Arid regions Densely populated regions Temperate climate forests 1.45 25 0.4... 

K., Van Dam D., Hetling L., Nosil M., Paustian K., and Alexander R. (2002) Sources of nitrate in rivers draining 16 major watersheds in the northeastern US isotopic constraints. Biochemistry 57/58, I7I-I92. 

Major run-off events are a feature of most intertidal areas associated with estuaries. The high flows may limit nutrient processing due to decreased water residence times however, if concentration increases with flow, nutrient processing may increase depending only on the biokinetics of the process. The concentration of nitrate in river water tends to increase with... 

Denitrification was shown to be a major process in removing nitrate in diverted river water (Yu et al 2006). The capacity of freshwater marsh to remove all nitrate in the diverted river water was strongly influenced by the flow or discharge rate (DeLaune et al 2005). The ponded wetland did not completely remove the nitrate in river water at high flow or discharge (>100 m s ). On the basis of mass balance calculation using concentration difference between inlet and outlet, the system removed the nitrate-N at the rate of approximately 60 mg N m day or approximately... 

Atrazlne has been found in ground water in Nebraska (24,43, 56,57), Wisconsin (54), and Iowa (55). The concentrations in several dozen wells were typically 0.8 ppb. The four positives out of nine wells sampled in Iowa were associated with an adjacent river which was contaminated with atrazlne by runoff. In 1979 and 1980, positive correlations between atrazlne and nitrate in ground water were reported (56,24). It has been estimated that 0,07% of the atrazlne applied to the surface leached to a 1.5 m depth in Nebraska (57). 

Fig. 6 Concentration ranges (5%, 50%, and 95% percentiles) of nitrate in six glacier streams (Gla), two alpine streams (Ver, Cal), one prealpine stream (Erl), three alpine rivers Rhine (Rhi), Rhone (Rho), and Ticino (Tic) and the midland river Thur (Thu)...

Figure 9. Analysis of anions and cations in river water using tartaric acid/18-crown-6/methanol-water eluent with a carboxylated polyacylate stationary phase in the protonated form. Ions 1) sulfate 2) chloride 3) nitrate 4) eluent dip 5) unknown 6) sodium 7) ammonium 8) potassium 9) magnesium 10) calcium (from ref. 80)...

Goolsby, D.A., R.H. Coupe, and D.J. Markovchick (1991b). Distribution of selected herbicides and nitrate in the Mississippi River and its major tributaries, April through June 1991. Open-File Report US Geological Survey, No. 91-4163 35 pp. 

Zelinski et al. [30] applied the technique to the determination of 0.02-0.lmg L 1 quantities of chloride, nitrate, sulphate, nitrite, fluoride and phosphate in river water. Approximately 25min was required for a full analysis. These workers used a column coupling technique which, by dividing the analysis into two stages, enables a high load capacity and a low detection limit to be achieved simultaneously without an appreciable increase in the analysis time. 

Fig. 2.15 Arsenate in river water sample size 5ml, 50ng of As(V) added—major peaks (1) fluoride (2) chloride (3) nitrate (4) sulphate.

High performance liquid chromatography on a small bore column packed with microparticulate silica based ion exchange material has been used [317] to determine down to 0.01 mg L 1 nitrate in water without interference from other ions associated with potable, pond, river and stream water. 

Cai, W.J., Wiebe, W.J., Wang, Y., and Sheldon, J.E. (2000) Intertidal marsh as a source of dissolved inorganic carbon and a sink of nitrate in the Satilla River estuarine complex in the southeastern U.S. Lirnnol. Oceanogr. 45, 1743-1752. 

During the second part of the 20th century, river flux of organic matter, nutrients and pollutants markedly increased. For example, increase in concentration of ammonia nitrogen is 2.5 times, of nitrites and nitrates 4 and 5 times respectively, of phosphate 2 times. Since the beginning of 1970s, the concentration of heavy metals and oil in river water has also increased [9]. Over the period 1996-2000, the input of the contaminants to the Black Sea with the Danube waters comprises oil 53 x 1012 t, Cu 1.2 x 1012 t, and Zn 3.3 x 1012t [9],... 

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