Halogens (fluorine, chlorine, bromine and iodine) were determined by activation analyses (neutron activation analysis (NAA), photon activation analysis (PAA) and prompt gamma-ray analysis (PGA)) for geological and cosmochemical solid samples. We studied how each analytical method was for the determination of trace amounts of halogens in rock samples. Radiochemical NAA (RNAA) showed the highest ...

2.1 Relationship between Oxidizing Power of Chlorine and Sodium Hypochlorite Many consumers are currently replacing chlorine with sodium hypochlorite as the oxidizing agent. In order to calculate how much sodium hypochlorite is required to replace the oxidizing power of chlorine, the following example is provided. If sodium hypochlorite is used to oxidize iodide in a solution of acetic acid, th...

This study was conducted to investigate the effect of free chlorine concentrations in wash water on Escherichia coli O157:H7 reduction, survival, and transference during washing of fresh-cut lettuce. The effectiveness of rewashing for inactivation of E. coli O157:H7 on newly cross-contaminated produce previously washed with solutions containing an insufficient amount of chlorine also was assess...

Public large scale use of chlorine-disinfected water began in the early years of the 20th century and resulted in dramatic reductions in observed rates of dysentery causing diseases, particularly cholera and typhoid infections 1 . Today in the USA 98% of water treatment plants use chlorine-based disinfectants to treat water 2 and similar chlorine disinfection use patterns of water treatment occ...

The effect of chlorine-induced bacterial injury on spectral features using Fourier transform infrared (FT-IR) absorbance spectroscopy was studied using a mixed bacterial culture of (1:1) ca. 500 CFU/mL each Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 15442 in 0.9% saline. Bacterial cells were treated with 0, 0.3, or 1.0 ppm of initial free chlorine (21 degrees C, 1 h of contact ...

Persistence of Bacillus globigii spores, a surrogate for Bacillus anthracis, was studied on biofouled concrete-lined slides in drinking water using biofilm annular reactors. Reactors were inoculated with B. globigii spores and persistence was monitored in the bulk and biofilm phases, first in dechlorinated water and later with free chlorine concentrations of 1 and 5 mg/L. In the dechlorinated s...

In human subjects 15-min exposure to 0.5-1.0 ppm chlorine gas causes a nasal obstructive response in the absence of a marked sensation of irritation. The current investigation was designed to assess the response of the mouse for comparative purposes. Respiratory physiological responses were measured in female C57Bl/6J mice exposed to 0.8 to 4.0 ppm chlorine gas. Chlorine was a potent sensory ir...

The objective of this paper is to evaluate the change in Bacillus subtilis spore survival and dimensions following ultraviolet and chlorine disinfection in water. Disinfection was monitored by using tools such as atomic force microscopy AFM , particle sizing by the electrozone sensing technique and fluorescence of spores after staining with an optical brightener. Results indicated that there wa...

We studied the resistance of various mycobacteria isolated from a water distribution system to chlorine. Chlorine disinfection efficiency is expressed as the coefficient of lethality (liters per minute per milligram) as follows: Mycobacterium fortuitum (0.02) > M. chelonae (0.03) > M. gordonae (0.09) > M. aurum (0.19). For a C.t value (product of the disinfectant concentration and contact time)...