Sodium chloride sensitivity threshold

Three factors determine how much brine can be disposed of in a field, assuming that the brine does not contain boron. The first factor is the type of crop crown. Different crops tolerate different levels of salt. For example, some clovers are extremely sensitive to salt, while some grasses, like tall fescue, are quite tolerant (Table 11.2). The second factor is the CEC of the soil. A soil with a CEC of 10 meq 100 g-1 can tolerate approximately 460 lb of sodium per acre (10% of CEC) before it reaches its critical toxicity threshold. However, a soil with a CEC of 20 meq 100 g 1 can tolerate up to 920 lb of sodium per acre before it reaches its critical threshold. The third factor is the texture of the soil. A sandy soil can take very little sodium chloride salt before it... 

Determination of the recognition thresholds of aqueous solutions of the umami tasting monosodium glutamate (MSG) and the salty tasting sodium chloride (NaCl), respectively, in the absence or presence of equimolar amounts of the alapyridaine enantiomers revealed that the detection thresholds of MSG (1.5 mmol/L) and NaCl (10 mmol/L) were 8 and 5 times lower when (+)-(5 )-alapyridaine was present 13). On the basis of these data it might be concluded that alapyridaine is a multivalent taste enhancer increasing the human sensitivity for sweetness, saltiness, and umami taste. 

Although most patch testing is done with nickel sulfate because it is less irritating than nickel chloride, exposure of the skin to nickel alloys results in the release of nickel chloride from the influence of human sweat. Therefore, nickel chloride is the more relevant form of nickel for examining threshold concentrations (Menne 1994). Menne and Calvin (1993) examined skin reactions to various concentrations of nickel chloride in 51 sensitive and 16 nonsensitive individuals. Although inflammatory reactions in the sweat ducts and hair follicles were observed at 0.01% and lower, positive reactions to nickel were not observed. To be scored as a positive reaction, the test area had to have both redness and infiltration, while the appearance of vesicles and/or a bullous reaction were scored as a more severe reaction. At 0.1%, 4/51 and 1/51 tested positive with and without 4% sodium lauryl sulfate. Menne et al. (1987) examined the reactivity to different nickel alloys in 173 nickel-sensitive individuals. With one exception (Inconel 600), alloys that released nickel into synthetic sweat at a rate of <0.5 pg/cmVweek showed weak reactivity, while alloys that released nickel at a rate of >1 pg/cm /week produced strong reactions. 

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