Daily Archives: August 13, 2011

Voice et al 2011: Field Deployable Method for Arsenic Speciation in Water

Field sampling of drinking water for arsenic is complicated by the fact that it can exist in several different forms. These authors have developed a method that reportedly can satisfactorily distinguish between As (III), As (V), monomethylarsonic acid (MMA) and dimethylarsenic acid (DMA).

Voice, T.C., L.V. Flores Del Pino, I. Havezov, and D.T. Long. 2011. Field Deployable Method for Arsenic Speciation in Water. Phys Chem Earth. 2011;36(9-11):436-441.

Abstract is below. Click here to obtain the full paper (fee).

Abstract (National Library of Medicine)

Contamination of drinking water supplies by arsenic is a world-wide problem. Total arsenic measurements are commonly used to investigate and regulate arsenic in water, but it is well understood that arsenic occurs in several chemical forms, and these exhibit different toxicities. It is problematic to use laboratory-based speciation techniques to assess exposure as it has been suggested that the distribution of species is not stable during transport in some types of samples. A method was developed in this study for the on-site speciation of the most toxic dissolved arsenic species: As (III), As (V), monomethylarsonic acid (MMA) and dimethylarsenic acid (DMA). Development criteria included ease of use under field conditions, applicable at levels of concern for drinking water, and analytical performance.The approach is based on selective retention of arsenic species on specific ion-exchange chromatography cartridges followed by selective elution and quantification using graphite furnace atomic absorption spectroscopy. Water samples can be delivered to a set of three cartridges using either syringes or peristaltic pumps. Species distribution is stable at this point, and the cartridges can be transported to the laboratory for elution and quantitative analysis. A set of ten replicate spiked samples of each compound, having concentrations between 1 and 60 µg/L, were analyzed. Arsenic recoveries ranged from 78-112 % and relative standard deviations were generally below 10%. Resolution between species was shown to be outstanding, with the only limitation being that the capacity for As (V) was limited to approximately 50 µg/L. This could be easily remedied by changes in either cartridge design, or the extraction procedure. Recoveries were similar for two spiked hard groundwater samples indicating that dissolved minerals are not likely to be problematic. These results suggest that this methodology can be use for analysis of the four primary arsenic species of concern in drinking water supplies.

Iron-Fortified Drinking Water Studies for the Prevention of Children’s Anemia in Developing Countries

This is an interesting review article that discusses adding iron to drinking water to prevent childhood anemia in different situations, including preschool children in a day care center, low socioeconomic families in Brazil, and implementation at the community level. In the United States, the US Environmental Protection Agency (USEPA) is specifically prohibited from requiring public water system to add substances to achieve health benefits.

Dutra-de-Oliveira, J.E., J.S. Marchini, J. Lamounier, and C.A. Almeida. Iron-Fortified Drinking Water Studies for the Prevention of Children’s Anemia in Developing Countries. Anemia. 2011;2011:815194. Epub 2011 Aug 4.

Department of Internal Medicine, Ribeirão Preto School of Medicine, University of São Paulo, Av Bandeirantes 3900, 14049-900 Ribeirao Preto, SP, Brazil.

Abstract is below. Click here for the full study (open source).

Abstract (National Library of Medicine)

Anemia and iron deficiency should receive special attention considering their high prevalence and serious consequences. For prevention, globally it is recommended to increase dietary iron intake, iron fortification of industrialized foods, and medical iron supplementation. Food fortification for the prevention of iron deficiency in developing countries should consider carriers locally available and consumed daily, requiring limited infrastructure and technology. Drinking water is the iron carrier we have been working for years for the prevention of iron deficiency and anemia in small children in Brazil. It was shown that studies with iron-fortified drinking water were proved to be effective on children’s anemia prevention. Water is found everywhere, consumed daily by everyone may be easily fortified with simple technology, is low priced and was effective on the prevention of children’s anemia. Fortification of drinking water with iron was locally implemented with the direct participation of the government and community. Government authorities, health personnel and population were part of the project and responsible for its community implementation. The mayor/municipality permitted and supported the proposal to supply it to children at their day-care centers. To keep the children drinking water iron fortified supply an officially authorized legislation was also approved.