Cadmium content

Into a conical flask, pipette a 50.0 or 100.0 mL aliquot of the solution and adjust the pH to 1-2 with aqueous ammonia solution (use pH test-paper). Add five drops of xylenol orange indicator and titrate with additional 0.05 M EDTA until the colour changes sharply from red to yellow. This gives the bismuth content. Record the total (combined) volume of EDTA solution used. Now add small amounts of hexamine (ca 5g) until an intense red-violet coloration persists, and titrate with the standard EDTA to a yellow end point the further consumption of EDTA corresponds to the lead-plus-cadmium content. 

To determine the cadmium content, add 20-25 mL of the 1,10-phenanthroline solution and titrate the liberated EDTA with the 0.05M lead nitrate solution until the colour change from yellow to red-violet occurs — a little practice is required to discern the end point precisely. Introduce further 2-5 mL portions of the 1,10-phenanthroline solution and note whether the indicator colour changes if so, continue the titration with the lead nitrate solution. The consumption of lead nitrate solution corresponds to the cadmium content. 

Cadmium concentrations in Israeli soils are in the range of 0.07-2.13 and average 0.37 0.34 mg/kg, while cadmium content in Terra-Rossa and Desert Stony soils is higher than that in Rendzina. 

Bingham F.T., Page A.L., Mahler R. J., Ganji T.J. Yield and cadmium accumulation of forage species in relation to cadmium content of sludge-amended soil. J Environ Qual 1976 5 57-60. 

Lovett, R.J., W.H. Gutenmann, I.S. Pakkala, W.D. Youngs, D.J. Lisk, G.E. Burdick, and E.J. Harris. 1972. A survey of total cadmium content of 406 fish from 49 New York State freshwaters. Jour. Fish Res. Board Canada 29 1283-1290. 

In 1991 the EU passed a directive to prohibit the use of cadmium pigments as colorants for certain plastics that can easily be colored with other pigments [3.122]. A transition period was granted for further series of plastics, these must not be colored with cadmium pigments since 01.01.96. The maximum cadmium content in plastics is limited to 0.01 %, because in this range only technical caused impurities are possible and a technical convenient coloring is not practicable. 

Radiochemical yields are 80-95% for zinc and quantitative for cadmium. The average relative standard deviation was 25% for zinc and better than 10% for cadmium. The detection limit of the method is 50 ppm cadmium in the ash. Analysis of two Illinois coals with unusually high cadmium content (17 and 21 ppm) gave results in good agreement with those obtained by atomic absorption and by anodic stripping voltammetry (4). The recent development and testing of a radiochemical method for the determination of zinc, cadmium, and arsenic in coal and fly ash, by Orvini et al. (14), has already been discussed in the section on arsenic. 

Table XVI shows the lead and cadmium content of one of the Pittsburgh seam coals used in the coal combustion study, and Table XVII shows the results obtained when the coal was combusted in the two experimental furnaces. Compared with mercury, a greater amount of both the cadmium and the lead were retained by the ash in both combustors.

Under (1) assume that you have collected and analyzed a number of water samples of different origin for acidity (pH), hardness (H), and lead and cadmium content (Pb, Cd). 

Hester K. and Boyle E. (1982) Water chemistry control of cadmium content in recent benthic foraminifera. Nature 298, 260-262. 

Reports of SEC with ICP-MS detection in the literature have principally concerned the separation of metalloproteins [32,72-78]. Dean and coworkers [73] used SEC with a Tris HC1 mobile phase in an attempt to determine the cadmium content in two metalloproteins. A further study used this technique for the speciation of Cd in pig kidney samples [77]. The majority of cadmium was associated with a pro-... 

S. Karavoltsos, A. Sakellari, M. Dimopoulos, M. Dasenakis, M. Scoullos, Cadmium content in foodstuffs from the Greek market, Food Addit. Contam., 19 (2002), 954-962. 

Mo-Tian Zhao, Jun Wang, Baikeng Lu, Hai Lu, Certification of the cadmium content in certified reference materials for Cd rice flour, Rap. Commun. Mass Spectrom., 19 (2005), 910-914. 

T. Watanabe, S. Shimbo, C.-S. Moon, Z.-W. Zhang, M. Ikeda, Cadmium contents in rice samples from various areas in the world, Sci. Total Environ., 184 (1996), 191-196. 

I. F. Rivai, H. Koyama, S. Suzuki, Cadmium content in rice and its daily intake in various countries, Bull. Environ. Contam. Toxicol., 44 (1990), 910-916. 

B. E. Guthrie, Chromium, manganese, copper, zinc and cadmium content, of New Zealand foods, New Zealand Med. J., 82 (1975), 418-424. 

Weston normal element (cell) — Electrochemical -> standard cell showing a particularly stable and reproducible cell voltage. In the international Weston normal element a cadmium amalgam (cadmium content in the solid phase approx. 15 wt %, in the liquid phase approx. 5wt%, total average 12 to 12.5 wt%, the electrode potential depends only on the temperature, not on the mass ratio of liquid and solid phases) and a mercury electrode (half-cell) are combined according to... 

Derived Products - Determination of Cadmium Content - Flameless Atomic Absorption Spectrometric Method (1983). 

International Organization for Standardization ISO 15774, Animal and Vegetable Fats and Oils - Determination of Cadmium Content by Direct Graphite Furnace Atomic Absorption Spectrometry (2000). 

International Organization for Standardization ISO 11212-4, Starch and Derived Products -Fleavy Metals Content - Part 4 Determination of Cadmium Content by Atomic Absorption Spectrometry with Electrothermal Atomization (1997)... 

Figure 9 Measurements of " C/C ratio in a benthic coral from 1.8 km depth in the northern Atlantic reveal that the base has an apparent age 650 radiocarbon years younger than the top. Yet °Th ages on the base and crest are nearly identical (1.54XlO" yr calendar years). Adkins et al. (1998) (reproduced by permission of Jess Adkins) attribute this difference to an abrupt invasion of low " C and high cadmium content Southern Ocean water.

Due to the wide use of cadmium-based products, cadmium is widely distributed in the environment. The cadmium content in soil and water has been increasing as a result of disposal of cadmium-contaminated waste and the use of cadmium-containing fertilizers (particularly on cereal crops). Commercial sludge, contaminated with cadmium, has been used to fertilize agricultural fields. Cadmium concentrations in urban air are quite low, because of regulation of industrial air emissions. Lead and zinc smelters and waste incineration account for the majority of cadmium present in ambient air. 

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