potassium-permanganate and chloramine

Arsenic is widespread in soils, water and air. In natural water the main forms are arsenite (As(III)) and arsenate (As(V)). The consumption of water containing high concentration of arsenic produces serious effects on human health, like skin and lung cancer. In Italy, Legislative Decree 2001/31 reduced the limit of arsenic from 50 to 10 μg/L, in agreement with the European Directive 98/83/EC. As consequence, many drinking water treatment plant companies needed to upgrade the existing plants where arsenic was previously removed or to build up new plants for arsenic removal when this contaminant was not previously a critical parameter. Arsenic removal from water may occur through the precipitation with iron or aluminum salts, adsorption on iron hydroxide or granular activated alumina (AA), reverse osmosis and ion exchange (IE). Some of the above techniques, especially precipitation, adsorption with AA and IE, can reach good arsenic removal yields only if arsenic is oxidized. The aim of the present work is to investigate the efficiency of the oxidation of As(III) by means of four conventional oxidants (chlorine dioxide, sodium hypochlorite, potassium permanganate and monochloramine) with different test conditions: different type of water (demineralised and real water), different pH values (5.7-6-7 and 8) and different doses of chemicals. The arsenic oxidation yields were excellent with potassium permanganate, very good with hypochlorite and low with monochloramine. These results were observed both on demineralised and real water for all the tested reagents with the exception of chlorine dioxide that showed a better arsenic oxidation on real groundwater than demineralised water.

Topics: Arsenic; Chloramines; Chlorine Compounds; Hydrogen-Ion Concentration; Hypochlorous Acid; Oxidants; Oxidation-Reduction; Oxides; Potassium Permanganate; Water; Water Purification

Exposure to endotoxins in treated drinking water can occur through ingestion, dermal abrasions, inhalation of water vapor, intravenous injection or during dialysis. While the risks associated with endotoxin ingestion and entry through dermal abrasions are not well quantified, adverse effects of intravenous injection and dialysis are well known and some studies indicate that inhalation of moisture-laden air may impact human health. This study quantifies the inactivation of endotoxin derived from Escherichia coli O55:B5 by three substances used either as disinfectants or oxidants in drinking water treatment: chlorine, monochloramine and potassium permanganate. Inactivation rates were found to be 1.4, 1.0 and 0.7 endotoxin units (EU)/mL h, for free chlorine, potassium permanganate and monochloramine, respectively. These rates are relatively slow given that contact times in drinking water distribution systems are typically less than 48 h. While small amounts of endotoxin may be removed by oxidation the observed removals are much less than those provided by physical removal processes. The significance of this finding is important for dialysis considerations but is as yet unclear with regard to inhalation, as the risk of inhaling sufficient quantities of endotoxin-containing aerosolized water droplets to adversely affect human health has not yet been adequately quantified.

Topics: Aerosols; Chloramines; Chlorine; Disinfectants; Endotoxins; Escherichia coli; Humans; Inhalation Exposure; Oxidants; Oxidation-Reduction; Potassium Permanganate; Renal Dialysis; Risk Assessment; Water Pollutants; Water Purification

The effect on the microbial ulcer flora of wet gauze dressings soaked in antiseptic solutions used for desloughing leg ulcers is not known. Quantitative cultures were therefore performed in 45 venous leg ulcers, before application and after 15 minutes' treatment with gauze dressings with four different antiseptic solutions: aluminium acetotartrate (Alsol) 1%, potassium permanganate 0.015%, acetic acid 0.25% and chloramine 0.25%. The percentage of ulcers with each type of microorganism did not differ before and after application of the antiseptic solutions. Staphylococcus aureus was found in 79% of the ulcers, gram-negative rods in 39%, S. epidermidis in 21%, Proteus spp in 21%, Pseudomonas spp in 14% and fungi in none. Potassium permanganate reduced the mean number of bacteria per ulcer from 4.4 x 10(6) to 0.9 x 10(6) (ns), chloramine from 2.7 x 10(6) to 2.2 x 10(6) (ns), Alsol from 1.2 x 10(7) to 3.5 x 10(6) (ns) and acetic acid from 6.3 x 10(6) to 2.6 x 10(5) (p = 0.007). S. aureus was reduced by acetic acid (p = 0.002), gram-negative rods by both chloramine (p = 0.03) and acetic acid (p = 0.03). The number of Pseudomonas, Proteus, S. epidermidis and Streptococcus haemolyticus group G was not reduced significantly (p > 0.05) by any of the solutions.

Topics: Acetates; Administration, Cutaneous; Aged; Anti-Infective Agents, Local; Bacteria; Bandages; Chloramines; Colony Count, Microbial; Female; Humans; Male; Potassium Permanganate; Proteus; Pseudomonas; Staphylococcus aureus; Staphylococcus epidermidis; Streptococcus; Tartrates; Varicose Ulcer

Topics: Acetates; Acetic Acid; Chloramines; Ethanol; Food Contamination; Potassium Permanganate; Yersinia

Topics: Acids; Chloramines; Hydrocarbons, Iodinated; Iodides; Iodine Compounds; Light; Mechlorethamine; Nitrogen Mustard Compounds; Phenol; Phenols; Photophobia; Potassium; Potassium Permanganate; Resorcinols