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Well‐switching programs in Bangladesh have successfully lowered arsenic exposure. In these programs, households switch from wells that are labeled "unsafe" to nearby wells labeled "safe," but these designations are usually based on inherently inaccurate field kit measurements. Here, we (a) compare the efficacy of field‐kit measurements to accurate laboratory measurements for well switching, (b) investigate the potential impact on well switching of the chosen "safe" threshold, and (c) consider the possible benefits of providing more detailed concentration information than just "safe" and "unsafe." We explore different hypothetical mitigation scenarios by combining two extensive data sets from Araihazar Bangladesh: a blanket survey of 6595 wells over 25 km2 based on laboratory measurements and 943 paired kit and laboratory measurements from the same area. The results indicate that the decline in average arsenic exposure from relying on kit rather than laboratory data is modest in relation to the logistical and financial challenge of delivering exclusively laboratory data. The analysis further indicates that the 50 μg/L threshold used in Bangladesh to distinguish safe and unsafe wells, rather than the WHO guideline of 10 μg/L, is close to optimal in terms of average exposure reduction. We also show that providing kit data at the maximum possible resolution rather than merely classifying wells as unsafe or safe would be even better. These findings are relevant as the government of Bangladesh is about to launch a new blanket testing campaign of millions of wells using field kits. Plain Language Summary: Arsenic contaminates groundwater across much of Bangladesh, poisoning millions of people who rely on well water for drinking. Well‐switching programs have proved useful for lowering arsenic exposures. In well‐switching programs, households with high‐arsenic wells switch to nearby wells with low arsenic for drinking. However, several important questions remain for designing future well‐switching programs: Do inexpensive field kits provide sufficiently accurate arsenic concentration measurements for determining which wells are safe and which are unsafe? What arsenic concentration is the best threshold for designating wells as safe? In this analysis, we use two large datasets from Ariahazar Bangladesh, a district where the arsenic problem has been extensively studied. Our results indicate that the average decline in arsenic exposure for a switching program that is based on cheap kit measurements is comparable to that of a program that uses more accurate, but expensive and logistically challenging, laboratory measurements. We also show that the 50 μg/L threshold used in Bangladesh to distinguish safe and unsafe wells is close to the optimal value for reducing arsenic exposure. These findings will be useful to the government of Bangladesh that is about to launch a new blanket testing campaign of millions of wells using field kits. Key Points: Well‐switching based on kit or laboratory measurements produces similar reductions in arsenic exposureThe optimal well switching threshold for reducing arsenic exposure is near 50 μg/L, higher than the WHO guideline of 10 μg/LProviding actual kit readings instead of classifying wells as just "unsafe" or "safe" could lead to a higher reduction in arsenic exposure [ABSTRACT FROM AUTHOR]

Abstract Well‐switching programs in Bangladesh have successfully lowered arsenic exposure. In these programs, households switch from wells that are labeled “unsafe” to nearby wells labeled “safe,” but these designations are usually based on inherently inaccurate field kit measurements. Here, we (a) compare the efficacy of field‐kit measurements to accurate laboratory measurements for well switching, (b) investigate the potential impact on well switching of the chosen “safe” threshold, and (c) consider the possible benefits of providing more detailed concentration information than just “safe” and “unsafe.” We explore different hypothetical mitigation scenarios by combining two extensive data sets from Araihazar Bangladesh: a blanket survey of 6595 wells over 25 km2 based on laboratory measurements and 943 paired kit and laboratory measurements from the same area. The results indicate that the decline in average arsenic exposure from relying on kit rather than laboratory data is modest in relation to the logistical and financial challenge of delivering exclusively laboratory data. The analysis further indicates that the 50 μg/L threshold used in Bangladesh to distinguish safe and unsafe wells, rather than the WHO guideline of 10 μg/L, is close to optimal in terms of average exposure reduction. We also show that providing kit data at the maximum possible resolution rather than merely classifying wells as unsafe or safe would be even better. These findings are relevant as the government of Bangladesh is about to launch a new blanket testing campaign of millions of wells using field kits.

Poisoning by organophosphorus compounds (OP) still poses a major medical challenge. Diagnosis of clinical signs of OP poisoning is still the most important parameter for the initiation of specific treatment. However, in case of unspecific signs and of delayed onset of cholinergic crisis a rapid, reliable and on-site analysis of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity would be of great value. Recently the ChE check mobile, a CE-certified ready to use kit for the determination of whole blood AChE and BChE activities, was developed. Here, we evaluated whole blood AChE and BChE reference values with samples taken from 181 male and 61 female volunteers and analyzed them on-site with the ChE check mobile test kit. The analysis of the data revealed a large inter-individual variability (BChE > AChE), only a small sex difference for AChE but a significant difference for BChE activities. The now available normal range values enable an evaluation of determined AChE and BChE activities in case of suspected exposure to OP nerve agents and pesticides. However, the large inter-individual variability of AChE and BChE activities calls for the determination of pre-exposure values in specific subpopulations in order to enable the diagnosis of low-level OP exposure. [ABSTRACT FROM AUTHOR]

Regular monitoring of salt at consumption level is very important for the control of iodine deficiency disorders through iodine fortified salt. A simple and inexpensive single solution field kit, specific to iodate, was developed for this purpose. The kit showed reproducible results for the target range of 0-50 parts per million (ppm) of iodine. The minimum detectable iodine level was 1.02 ± 0.012 ppm (mean ± 2SD, 95 % CI). The shelf-life of the kit was more than 2 years. The cost of one kit that monitors 100-150 salt samples was 7 cents (0.07$). Instructions for preparing the field kit are presented. The performance of the kit was evaluated against laboratory iodometric titration. About 2,32,000 salt samples in the field and 1,224 samples in the laboratory were tested. Excellent agreement was observed between the results of the kit and iodometric titration (R = 0.999). The intake of adequately iodated salt determined by the kit and iodometric titration was 43 % and 44 % respectively. There were no false positive results when bromate or bleaching powder was substituted in place of iodate in salt. [ABSTRACT FROM AUTHOR]

Arsenic, a common contaminant of groundwater, affects human health adversely. According to the World Health Organization (WHO), the maximum recommended contamination level of arsenic in drinking water is 10 μg/L. The purpose of this research was to develop user-friendly kits for detection of arsenic to measure at least up to 10 μg/L in drinking water, so that a preventive measure could be taken. Two different kits for detection of total arsenic in water are reported here. First, the arsenic in drinking water was converted to arsine gas by a strong reducing agent. The arsine produced was then detected by paper strips via generation of color due to reaction with either mercuric bromide (KIT-1) or silver nitrate (KIT-2). These were previously immobilized on the detector strip. The first one gave a yellow color and the second one grey. Both of these kits could detect arsenic contamination within a range of 10 μg/L–250 μg/L. The detection time for both the kits was only 7 min. The kits exhibited excellent performance compared to other kits available in the market with respect to detection time, ease of operation, cost and could be easily handled by a layman. The field trials with these kits gave very satisfactory results. A study on interference revealed that these kits could be used in the presence of 24 common ions present in the arsenic contaminated water. Though the kits were meant for qualitative assay, the results with unknown concentrations of real samples, when compared with atomic absorption spectrophotometer (AAS) were in good agreement as revealed by thet-test. [ABSTRACT FROM AUTHOR]

Recognizing the enormity and severity of the problem of arsenic poisoning in ground water, the capabilities of commercially available arsenic detection field kits were critically evaluated. In the light of findings of the evaluation of these kits, their merits and limitations; a simple, efficient, prudent, userfriendly, indigenous field kit has been developed. The kit can be used for rapid on-site screening of arsenic contaminated water sources and is capable of detecting arsenic concentration as low as 0.01 mg L-1, the guideline value for arsenic set by the WHO. The kit has been subjected to extensive laboratory and field testing. The details of development of the kit and its salient features are presented in the paper. [ABSTRACT FROM AUTHOR]

Abstract Background In many areas of Bangladesh, it has been more than six years since a national campaign to test tubewells for arsenic (As) was conducted. Many households therefore draw their water for drinking and cooking from untested wells. Methods A household drinking water survey of 6646 households was conducted in Singair upazilla of Bangladesh. A subset of 795 untested wells used by 1000 randomly selected households was tested in the field by trained village workers with the Hach EZ kit, using an extended reaction time of 40 min, and in the laboratory by high-resolution inductively-coupled plasma-mass spectrometry (HR ICP-MS). Results The household survey shows that more than 80% of the wells installed since the national testing campaign in this area were untested. Less than 13% of the households with untested wells knew where a low-As well was located near their home. Village workers using the Hach EZ kit underestimated the As content of only 4 out of 795 wells relative to the Bangladesh standard. However, the As content of 168 wells was overestimated relative to the same threshold. Conclusion There is a growing need for testing tubewells in areas of Bangladesh where As concentrations in groundwater are elevated. This could be achieved by village workers trained to use a reliable field kit. Such an effort would result in a considerable drop in As exposure as it increases the opportunities for well switching by households.

5-(4-Nitrophenyl)-2,4-pentadien-1-al (NPPD) can be used for chemical tracking in crime scene investigations. A color test kit for NPPD was developed for use by non-scientists, such as police officers, in the field. However, this kit had problems, including contact with concentrated HCl, and instability of the reagent (naphthoresorcinol methanol solution) used in the first step of color development. To overcome these problems, in the present study, a field kit was developed with the concentrated HCl sealed in a vial so it did not contact the operator. A glass tube with two compartments was used to separate the naphthoresorcinol and methanol before use. When the color test was conducted, a cotton swab was inserted into the tube. Before insertion, the cotton was used to collect a sample from a suspect that had been in contact with a surface sprayed with a 1% NPPD methanol solution. Insertion of the cotton swab broke the thin glass that separated the methanol and naphthoresorcinol, and any NPPD on the swab reacted with the naphthoresorcinol methanol solution. The cotton swab was then pushed further to break the glass separating the concentrated HCl. A red color then developed if NPPD was present on the cotton swab. For testing the kit, NPPD was sprayed in an area where a crime was expected to occur. This kit will be useful for detecting a contact with or near a crime scene, because samples do not require analysis in a forensic science laboratory. Instead, the results can be confirmed at the scene of crime. [ABSTRACT FROM AUTHOR]

• Concentrations of As in soil irrigated with high-As water vary across a range of spatial scales. • Mean As concentrations measured for a dozen samples with a field kit and by XRF are well correlated. • Farmers could use a field kit to decide whether to grow rice or switch to another crop. Rice is the primary crop in Bangladesh and rice yield is diminished due to the buildup of arsenic (As) in soil from irrigation with high-As groundwater. Soil testing with an inexpensive kit could help farmers target high-As soil for mitigation or decide to switch to a different crop that is less sensitive to As in soil. A total of 3240 field kit measurements of As in 0.5 g of fresh soil added to 50 mL of water were compared with total soil As concentrations measured on oven-dried homogenized soil by X-ray fluorescence (XRF). For sets of 12 soil samples collected within a series of rice fields, the average of kit As measurements was a linear function of the average of XRF measurements (r2 = 0.69). Taking into account that the kit overestimates water As concentrations by about a factor of two, the relationship suggests that about a quarter of the As in paddy soil is released in the kit's reaction vessel. Using the relationship and considering XRF measurements as the reference, the 12-sample average determined correctly whether soil As was above or below a 30 mg/kg threshold in 86% of cases where soil As was above the threshold and in 79% of cases where soil As was below the threshold. We also used a Bayesian approach using 12 kit measurements to estimate the probability that soil As was above a given threshold indicated by XRF measurements. The Bayesian approach is theoretically optimal but was only slightly more accurate than the linear regression. These results show that rice farmers can identify high-As portions of their fields for mitigation using a dozen field kit measurements on fresh soil and base their decisions on this information. [ABSTRACT FROM AUTHOR]

Arsenic field test kits are widely used to measure arsenic levels in drinking water sources, especially in countries like Bangladesh, where water supply is highly decentralized and water quality testing infrastructure is limited. From a public health perspective, the ability of a measurement technique to distinguish samples above and below relevant and actionable drinking water standards is paramount. In this study, the performance of eight commercially available field test kits was assessed by comparing kit estimates to hydride generation atomic absorption spectroscopy (HG-AAS) analyses. The results of tests that control for user-dependent color matching errors showed that two kits (LaMotte and Quick II kits) provided accurate and precise estimates of arsenic, four kits (Econo-Quick, Quick, Wagtech and Merck kits) were either accurate or precise, but not both, and two kits (Hach and Econo-Quick II kits) were neither accurate nor precise. Tests were performed for arsenic concentration ranges commonly found in natural waters and treated waters (such as community drinking water filter systems), and also on laboratory generated arsenic standards in DI water. For those kits that did not perform well, test strips often produced colors too light compared to manufacturer-provided arsenic color calibration charts. Based on these results, we recommend stakeholders carefully re-consider the use of poorly performing field test kits until better quality control of components of these kits is implemented. In addition, we recommend that field test kit manufacturers provide suitable internal standards in every kit box for users to verify the veracity of manufacturer provided color charts. Image 1 • Portable color scanners were used for a tester-independent evaluation of test kits. • Kit performance ranged from under-estimating arsenic to over-estimating arsenic. • Recalibration can improve accuracy but not precision of field kits. • Manufacturers can improve field kit design and facilitate quality assurance testing. • Stakeholders are urged to review their use of field kits for arsenic testing. [ABSTRACT FROM AUTHOR]