Articles

Naegleria deaths: desired chlorine level not maintained

Despite tall claims about taking effective measures to keep Naegleria fowleri in check, the civic agencies concerned still have to do a lot of work to save precious lives since a large quantity of water supplied to the city is still shockingly unhealthy and prone to assist the growth of ‘brain-eating’ amoeba,

Water Supply and Sanitation in Pakistan

Drinking water supply and sanitation in Pakistan is characterized by some achievements and many challenges.

WHO guidelines for water contamination

This fourth edition of the World Health Organization’s Guidelines for Drinking-water Quality builds on over 50 years of guidance by WHO on drinking-water quality,

Methods of Water Purification

Water treatment can be defined as any procedure or method used to alter the chemical composition or natural "behavior" of a water supply.

Chlorine in Drinking Water

Exposure to chlorine, hypochlorous acid, and hypochlorite ion through ingestion of household bleach occurs most commonly in children.

Chlorine in Drinking Water

ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE

Air

A mean ambient air level of 1 mg/m3 was reported for chlorine.

Water

Chlorine is present in most disinfected drinking-water at concentrations of 0.2–1 mg/litre.

Food

Cake flour bleached with chlorine contains chloride at levels in the range 1.3–1.9 g/kg. Unbleached flour may contain small amounts of chlorite (400–500 mg/kg).

 

Estimated total exposure and relative contribution of drinking-water

The major routes of exposure to chlorine are through drinking-water, food, and contact with items either bleached or disinfected with it.

KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS

Most studies on the pharmacokinetics of chlorine, hypochlorous acid, or hypochlorites employ reactive 36Cl-labelled compounds and probably reflect the fate of the chloride ion or other reaction products generated from the parent molecules. In rats, hypochlorous acid was readily absorbed through the gastrointestinal tract, distribution being highest in the plasma; smaller amounts were found in bone marrow, kidney, testes, lung, skin, duodenum, spleen, liver, and bone. In vivo, sodium hypochlorite was metabolized to trichloroethanoic acid, dichloroethanoic acid, chloroform, and dichloroacetonitrile. Hypochlorous acid administered to rats was excreted primarily in the urine and faeces, mostly in the form of chloride ion . None was excreted in...