Arsenic and high drowning rates of Bangladeshi kids

A recent study in Bangladesh links exposure to arsenic-contaminated drinking water during pregnancy to poor cognitive ability that increases the chance of death by drowning in children aged 1—5 years

Drowning accounts for 42 per cent of all deaths in Bangladeshi children aged 1—4 years. These deaths occur mostly in the rural areas of the deltaic country, with 75 per cent of them in natural water bodies less than 20 metres from the home.

Mahfuzar Rahman, lead author of the study - published in October by Global Health Action - and programme head of the research and evaluation division of BRAC, tells SciDev.Net that arsenic contamination might “impair intrauterine programming and foetal neurodevelopment which ultimately raises the risk of drowning among children.”

Rahman says: “In our five-year research it was found that 73 per cent of drowning deaths occurred among children of women who were exposed to arsenic during their pregnancy.” The study focused on the Matlab sub-district, about 55 kilometres from Dhaka, which is known to be highly arsenic-contaminated and where there is demographic surveillance data gathered by the iccdr,b.

Source: SciDevNet

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• Public Health
• Arsenic
• Human Rights

1 Comment

1. Below is a simple method to remove Arsenic from water.
   It can be done by a simple manual method to keep costs down. If anyone on this Network is interested, we can put forth a proposal that could be made under license in India or Bangladesh.
   Fact sheet: removal of iron, manganese and arsenic from ground water

   Chemical parameterSoluble fractionInsolublePermitted concentration in
   drinking waterTypical performance at
   5 - 10m/hr filtration velocity

   Manganese	Mn2+	Mn4+	50 ug/l	>80%
   Ferric	Fe2+	Fe3+	200 ug/l	>95%
   Arsenic	As3+	As5+	10ug/l	>90%

   Iron, manganese and arsenic are often found in borehole / tube wells and ground water at varying concentrations depending upon the geology of the ground. The technique used by Dryden Aqua to remove the chemicals is as is as follows;

   Process

   1. Oxidation reactions to convert metals from soluble ionic form to insoluble oxidized precipitate, pH correction and redox correction.
   2. Decantation may be required if the concentrations are above 5 mg/l, if not proceed to AFM® filtration
   3. AFM® filtration to remove the suspended metal oxide solids, there will also be adsorption reactions and surface oxidation reactions.

   Procedure

   Oxidation;
   This is achieved through aeration of the water. The water is aerated for a period of no less than 60 minutes. If water flow is 50 m3/hr the aeration level is 100m3/hr of air and tank volume is 50m3 of water. Dryden Aqua manufacture fine bubble drop in air diffusers for this application.

   pH;
   The pH of the water should be increased to a value over pH 7.5

   Redox;
   The aeration system should increase the redox potential of the water. It is important to raise the potential to as high a value as possible. Certainly it should be over 200mv.

   1. Manganese oxidation requires a high oxidation potential, in some cases if there is a high BOD or organic content in the water it may be required to add additional oxidizing agent such as hypochlorite, chlorine dioxide, hydrogen peroxide or ozone. As an option to using an oxidizing agent ferric may be injected into the water to act as a catalysts to co-precipitate Manganese. If this strategy is used the amount of ferric equates with 2 x the molar quantity of manganese, e.g. for 0.1mg/l of manganese add 0.2 mg/l of ferric.
   2. Ferric oxidation is simple, the aeration system will more than suffice.
   3. Arsenic oxidation also benefits from the addition of ferric to the water. Arsenic is removed by oxidation and co-precipitation with ferric, example 0.1 mg/l As requires up to 1 mg/l of ferric (as ferric chloride)

   AFM® filtration

   Pretreatment of the water prior to filtration by AFM® is very important. AFM® will remove the metals and metalloid by the following mechanisms;

   • Oxidation and adsorption (similar to greensands and ferric media)
   • Adsorption of sub-micron metal oxide particles
   • Physical filtration of most particles down to 1 micron.