Nitrates/nitrites causing

The majority of phosphate processes in use today are accelerated to obtain shorter treatment times and lower processing temperatures. The most common mode of acceleration is by the addition of oxidising agents such as nitrate, nitrite, chlorate and hydrogen peroxide. By this means, a processing time of 1 to 5 min can be obtained at temperatures of 43-71 °C. The resultant coatings are much smoother and thinner than those from unaccelerated processes, and, while the corrosion resistance is lower, they cause less reduction of paint gloss and are more suited to mass-production requirements. 

Note When combined with thin-layer chromatographic separation the reagent provides a specific detection method for nitrate and nitrite. The color development is often completed within a few minutes on silica gel plates. In the absence of ammonia vapor traces of oxides of nitrogen in the laboratory atmosphere can slowly cause the background to become reddish-brown. The simultaneous presence of the following ions in the chromatogram zones interferes with the detection of nitrate/nitrite I , 10J, IO4, MoO and H2PO2. 

Evaporation by heating a filtrate from precipitation of potassium cobaltinitrite caused it to turn purple and explode violently [1]. This was attributed to interaction of nitrite, nitrate, acetic acid and residual cobalt with formation of fulminic or methylnitrolic acids or their cobalt salts, all of which are explosive [2], Mixtures containing nitrates, nitrites and organic materials are potentially dangerous, especially in presence of acidic materials and heavy metals. A later publication confirms the suggestion of formation of nitro- or nitrito-cobaltate(III) [3],... 

Contact of the solid nitrate with fused nitrite causes incandescence. 

The LCM baths use a mixture of nitrate/nitrite eutectic salts. As it contains up to 40% sodium nitrite the salt system is toxic and can cause water pollution, and also cause nitrosation of volatile secondary amines. 

SACHEM Inc., located in Cleburne, Texas, is a producer of high-purity bulk chemicals for companies that have high-purity requirements in their chemical processing. As stated in Workplace Scene 1.2, one of their products is tetramethylammonium hydroxide (TMAH), which is sold to semiconductor industries. The analysis of TMAH for trace anions such as chloride, nitrate, nitrite, and carbonate is critical for SACHEM s quality control laboratory. If these ions are present on the integrated circuit boards manufactured by one of their semiconductor customers, they may cause corrosion severe enough to affect the functionality and performance of the electronic devices in which the circuit boards are used. In SACHEM s quality control laboratory, ion chromatography procedures have been developed to measure the anion concentrations in TMAH. Because the concentration levels are trace levels, a clean room environment, like that described in Workplace Scene 1.2, is used. A special procedure for carbonate analysis is required so that the absorption of carbon dioxide from the atmosphere can be minimized. 

Several members of this (often endothermic) group of compounds which contain heavy metals tend to explosive instability, and most are capable of violent oxidation under appropriate circumstances. Fusion of mixtures of metal cyanides with metal chlorates, perchlorates, nitrates or nitrites causes a violent explosion [1], Addition of one solid component (even as a residue in small amount) to another molten component is also highly dangerous [2], Individually indexed compounds are ... 

The stepwise nature of nitrification during the aerobic decomposition of detrital PON is illustrated in Figure 24.6. Initially, the degradation of PON produces ammonium, which stimulates the growth of the nitrate oxidizers. These bacteria transform the ammonium into nitrite, causing ammonium concentrations to decline and nitrite concentrations to rise. The elevated nitrite levels stimulate the growth of the nitrite oxidizers. These bacteria transform the nitrite into nitrate. Eventually all of the DIN is oxidized to nitrate. The residual pool of PON includes microbial biomass and any PON too inert to be degraded by aerobic marine bacteria. 

Fig. 1. The EDRF/NO pathway in vascular smooth muscle. Vasodilatation by nitrates at a cellular level. Nitrates, nitrites, and nitroprusside-Na are able to release nitric oxide (NO), which stimulates the conversion of GTP into cyclic guanosine monophosphate (cGMP), thus causing vasodilatation. The release of EDRF (=NO) from endothelial cells can be stimulated by various endogenous compounds. Endogenous EDRF (=NO) then causes vasodilatation, similar to the NO released by...

The reaction between different types of radical cation and nitrite ion (E° = 0.7 V in acetonitrile) has been extensively studied (Ristagno and Shine, 1971 Johnson and Dolphin, 1976 Shine et al., 1979 Smith et al., 1979 Eberson and Radner, 1980). Generally, one obtains nitration products from this reaction, and in view of its exergonic nature the mechanism most probably consists of an initial, very fast electron-transfer step, followed by a slower nitration reaction, caused by N02 (N204) from the first step. 

Several in vitro studies proved that treatment of intact erythrocytes with nitrites causes the oxidation of hemoglobin to methemoglobin by radical generation along with a decrease in reduced glutathione (GSH) level associated with erythrocyte membrane dysfunctions and namely altered cell ionic flux, lipid peroxidation, and perturbation of membrane transport (Batina et al 1990 May et al 2000). Nitrate/ nitrite-induced oxidation of biological molecules potentiates reactions, which interfere in the oxidative chain and which can affect some antioxidant systems. 

Table 7.1 presents the most important biochemical features obtained for the infants included in the study. All water samples collected from the areas known for an intense use of nitrogen mineral fertilizers exceeded the maximum contaminant level for nitrates of 50 mg Lthereby indicating that the acute nitrate/nitrite intoxication caused the clinically evaluated methemoglobinemia. 

Our investigations showed the decrease of SOD and GPx activities and an increase of MDA levels, which consequently caused acute nitrate/nitrite intoxication in infants. 

RDX dissolves in HNO3 of conens up to 70% witlr out decompg and may be recovered from soln by dilution with water. It is not attacked by either cold or hot coned HCl. It decomp completely by heating with an equal part of CafOH) fo 4 hrs at 60°. RDX decomposes slowly when heated at 60° with N/10 NaOH for 5 hrs, and rapidly when heated with N/lNaOH. The decompn products of RDX in alkaline solution which have been isolated are N, NH3, nitrates, nitrites, formaldehyde, hexamine and org acids (such as formic). When mixed with oxides of heavy metals (such as Fe Of Cu), RDX forms unstable compds, which may undergo decompn and cause ignition of mixts at temps as low as 100°... 

Additional calculations (10) indicated that the movements of the intrusions produced localized turbulent mixing ascribed to shear instabilities. These mixing events, driven by the M2 internal tides, caused a potentially efficient mechanism for vertical transport of heat and salt as input to the Scotian Shelf. These vertical-mixing events, which continually replenish nutrients (e.g., nitrates, nitrites, silicates, and inorganic phosphates) from slope waters below, can explain the anomalously high productivity occurring at the front. 

Horses, like other monogastrics, are more resistant to plants capable of causing nitrate-nitrite poisoning than are ruminants. However, horses can modestly reduce nitrates to nitrites in their cecums, but it requires about three times as much nitrate to produce the same toxic effect in horses as in ruminants. 

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