Effectiveness and Reliability of Arsenic Field Testing Kits:  Are the Million Dollar Screening Projects Effective or Not?

Abstract

The exposure of millions to arsenic contaminated water from hand tube wells is a major concern in many Asiatic countries. Field kits are currently used to classify tube wells as delivering arsenic below 50 microg/L (the recommended limit in developing countries) as safe, painted green or above 50 microg/L, unsafe and painted red. More than 1.3 million tube wells in Bangladesh alone have been tested by field kits. A few million U.S. dollars have already been spent and millions are waiting for the ongoing projects. However, the reliability of the data generated through field kits is now being questioned. Samples from 290 wells were tested by field kits and by a reliable laboratory technique to ascertain the reliability of field kits. False negatives were as high as 68% and false positives up to 35%. A statistical analysis of data from 240 and 394 other wells yielded similar rates. We then analyzed 2866 samples from previously labeled wells and found 44.9% mislabeling in the lower range (<50 microg/L) although mislabeling was considerably reduced in the higher range. Variation of analytical results due to analysts and replicates were pointed out adopting analysis of variance (ANOVA) technique. Millions of dollars are being spent without scientific validation of the field kit method. Facts and figures demand improved, environmentally friendly laboratory techniques to produce reliable data.

Food for Thought: A Critical Overview of Current Practical and Conceptual Challenges in Trace Element Analysis in Natural Waters

“…Table 1 lists some problems identified and corresponding improvements. Certain widely-used commercial field tests have been criticized for insufficient sensitivity and high rates of false-positives and false-negatives [66]. It is also clear that a method that produces a toxic gas such as arsine, uses toxic and difficult-to-dispose-of reagents (e.g., mercury, lead, tin, etc.…”

Environmental Irony: Summoning Death in Bangladesh

“…Rahman et al (2002) have written a particularly damning assessment of the four most commonly used FTKs. When calibrated against laboratory-based flow injection hydride generation atomic absorption spectrometry (FIHGAAS), they were reliable only at high concentrations (>0.10 mg/l) and correctly identified the binary status (acceptable or contaminated) of the water in only 49.3 per cent of the 2,866 tubewells tested.…”

“…Professor Dipankar Chakraborti, for instance, is Director of the School of Environmental Sciences at Jadavpur University, Kolkata, and he has made a major contribution to debates about testing water to determine the extent of the pollution, and also on the remedial technologies that could be used either to remove the poison or provide safe surface water supplies. He and his team (Chakraborti et al, 2002;2003; are pessimistic in their assessment of the health effects, suggesting that the number of patients identified so far is just 'the tip of the iceberg'. They report over 300,000 cases of visible skin lesions in the Indian state of West Bengal alone, and suggest that there are likely to be many more in neighbouring Bangladesh.…”

Field based speciation of arsenic in UK and Argentinean water samples

“…Poor correlation between field kits employing arsine generation and laboratory-based measurements of 'total' arsenic are reportedly common (Hussam et al, 1999;Rahman et al, 2002;Arora et al, 2009). This method presents health and safety risks to the operator from the generation of arsine gas, of which up to 50 % can escape from reaction cells (Hussam et al, 1999), handling of HCl in the field and resultant mercury solid wastes (Melamed, 2004) or oxalic acid when used for arsine generation (Baghel et al, 2007).…”