Cyanide concentrations

The rate of dissolution is limited by oxygen availabiUty rather than by cyanide concentration. When oxygen solubiUty is reduced by water salinity or by consumption by ore constituents such as sulfide minerals, enrichment of the air with oxygen or addition of hydrogen or calcium peroxide improves leaching kinetics and decreases cyanide consumption (10). 

Corrective Action Application At a hazardous waste treatment storage and disposal facility in Washington State, a cyanide-bearing waste required treatment. The influent waste stream contained 15 percent cyanide. Electrolytic oxidation was used to reduce the cyanide concentration to less than 5 percent. Alkaline chlorination was used to further reduce the cyanide concentration to 50 mg/1 (the cleanup objective). The electrolytic process was used as a first stage treatment because the heat of reaction, using alkaline chlorination to treat the concentrated cyanide waste, would be so great that it would melt the reactor tank. 

Internal stress of copper deposits may vary between —3.4MN/m (compressive) and -1- l(X)MN/m (tensile). In general, tensile stress is considerably lower in deposits from the sulphate bath than in those from cyanide solutions " , while pyrophosphate copper deposits give intermediate values. In cyanide solutions, tensile stress increases with metal concentration and temperature decreases if the free cyanide concentration is raised. P.r. current significantly lowers tensile stress. With some exceptions, inorganic impurities tend to increase tensile stress . Thiocyanate may produce compressive stress in cyanide baths . 

Total cyanide concentrations in ground water samples ranged from over 300 parts per million (ppm) at the plant site to about 1 5 ppm at a spring located along the banks of the Little Spokane River Wells used for drinking water, irrigation, and livestock purposes contained total cyanide concentrations as high as 23 ppm ... 

As a result of removing the sanitary discharge from the seepage lagoon, the shallow well (TH-1) located to the west of the seepage lagoon, showed a decrease In cyanide concentration. The well located Immediately downstream of the potllner pile and potllner work area did not Improve as expected. 

A leak of 20 gpm in a pressurized water line located in the area to the east of the old potliner cleaning building was observed in late June 1983 and corrected. The results of the leak are vividly shown by an increased cyanide concentration from March 1983 to mid-October 1983 in well HC-2A (Figure 9). This showed the need to carefully control water usage in the contaminated area. 

Cyanide contamination creates special public information problems, e.g. it is difficult to explain why cyanide is not included in the current drinking water standards but that aquatic organisms are affected at relatively low cyanide concentration. There is confusion on whether fresh water standards are based on free or complexed cyanides. Fortunately, the provision of a permanent drinking water supply to each affected household removed risk assessment as a major issue. 

Urinary excretion patterns of thiocyanate suggest that there are quantitative species differences in acrylonitrile metabolism (Ahmed and Patel 1981). Thiocyanate was identified as a metabolite in rats, mice, rabbits and Chinese hamsters. About 20 to 23% of the administered dose was excreted as thiocyanate in rats, rabbits and Chinese hamsters, while 35% was excreted as thiocyanate in mice (Gut et al. 1975). It has also been observed that mice metabolize acrylonitrile more rapidly than rats (Ahmed and Patel 1981 Gut et al. 1975). Maximum blood cyanide concentrations were observed 1 hour after dosing in mice, but 3 hours after dosing in rats (Ahmed and Patel 1981). In mice, thiocyanate was present in the urine within 4 hours of dosing, while in rats, thiocyanate was present in urine only at time intervals longer than 4 hours (Gut et al. 1975). 

In running the DIN 53436 method hydrocarbon and hydrogen cyanide has only been determined qualitatively. The cyanide concentration has been determined four times during the 30 minute steady state combustion process. From these experiments the average concentration of emission has been estimated. The other results presented in Table V from DIN 53436 experiments have been measured in similar ways as for the other small scale test methods. It may be observed that the amount of material burnt in each experiment is smaller than in previous test procedures. The results presented are average values of two deteminations of each material. 

A case in which cyanide concentration is higher than the normal reference range (0.02-0.05 /U.g/mL) in whole blood, or cyanide is detected in environmental samples. The case can be confirmed if laboratory testing is not performed because either a predominant... 

Time from autopsy to sample analysis, wherein cyanide concentrations may increase due to microbial action... 

In higher plants, elevated cyanide concentrations inhibited respiration (through iron complex-ation in cytochrome oxidase) and ATP production and other processes dependent on ATP, such as... 

No evidence of injuries or disease. Yellow fluorescent particles found in mouth appeared like those placed in NaCN ejector mechanisms used in predator control. However, blood cyanide concentration was similarto that found in nonexposed vultures, including two captive California condors... 

Organic cyanide compounds, or nitriles, have been implicated in numerous human fatalities and signs of poisoning — especially acetonitrile, acrylonitrile, acetone cyanohydrin, malonitrile, and succinonitrile. Nitriles hydrolyze to carboxylic acid and ammonia in either basic or acidic solutions. Mice (Mus sp.) given lethal doses of various nitriles had elevated cyanide concentrations in liver and brain the major acute toxicity of nitriles is CN release by liver processes (Willhite and Smith 1981). In general, alkylnitriles release CN much less readily than aryl alkylnitriles, and this may account for their comparatively low toxicity (Davis 1981). 

Intentional oral ingestion of unknown amount of NaCN or KCN, three cases Death between 5 and 30 min stomach cyanide concentrations ranged between 100 and 164 mg tissue residues postmortem, in mg cyanide/kg FW, were 0.3-1.1 in blood, 0.3-1.0 in liver, and 0.2-0.3 in brain 8... 

Drinking water, 1000 mg KCN/L, exposure for 40 days Marked inhibition of cytochrome oxidase activity in liver, brain, and blood increased cyanide concentrations in all tissues inhibition of rhodanese activity diminished labile sulfur tissue levels 43... 

Concentrations dropped from 1.6 mg/kg FW immediately after death to 1.2 in 1 day, 0.92 in 3 days, and 0.04 in 7 days Residues, in mg/kg FW, were 5.7 immediately after death, and 2.3 after 21 days Cyanide concentrations dropped from 2.0 mg/kg FWjust after death, to 0.8 in 7 days... 

All dead within 17 min cyanide concentrations postmortem, in mg/kg FW, were 3.3 in blood, 1.5 in plasma, 1.6 in serum, 1.4 in cerebrospinal fluid, 0.9 in brain grey matter, and 1.0 in brain white matter... 

Ballantyne, B. 1975. Blood, brain and cerebrospinal fluid cyanide concentrations in experimental acute cyanide poisoning. Jour. Forensic Sci. Soc. 15 51-56. 

Ballantyne, B., S.P. Boardman, J. Bright, DJ. Coffee, T.D. Weber, and P. Williams. 1972. Tissue cyanide concentrations and cytochrome oxidase activities in experimental cyanide poisoning. Brit. Jour. Pharmacol. 44(2) 382P-383P. 

Egekeze, J.O. and R.W. Oehme. 1979. Blood and liver cyanide concentrations in rats poisoned with oral doses of potassium cyanide. Toxicol. Eett. 3 243-247. 

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