Sea level rise from climate change is expected to increase the release of arsenic into Bangladesh's drinking well water by reduction and by the salt effect.

BACKGROUND: Over 165,000,000 people live in Bangladesh; approximately 97% of Bangladeshis drink well water. Approximately 49% of Bangladesh's area has drinking well water with arsenic (As) concentrations that exceed the 10 micrograms per liter (µg/L) World Health Organization (WHO) guideline. This exposure to a potent carcinogen is a significant threat to public health. About 21% of Bangladesh is flooded each year during a typical monsoon season. As climate change progresses, sea levels will continue to rise, and the area and duration of these annual floods will increase. We hypothesize that these consequences of climate change can increase the release of arsenic from sediments into Bangladesh's drinking well water. METHODS: Drinking well water samples were collected during a national-scale survey in Bangladesh. The dissolved oxygen concentration, oxidation-reduction potential, specific conductance, pH, and temperature were measured at sampling with calibrated portable electronic sensors. The arsenic concentration was measured by the silver diethyldithiocarbamate method. RESULTS: As the concentration of dissolved oxygen decreases, the concentration of arsenic increases (p-value = 0.0028). Relatedly, as the oxidation-reduction potential decreases, the concentration of arsenic increases (p-value = 1.3×10-5). This suggests that arsenic is released from sediments into Bangladesh's drinking well drinking water by reduction. As the specific conductance increases, the concentration of arsenic increases (p-value = 0.023). This suggests that arsenic is also released from sediments into water by the salt effect. CONCLUSIONS: Rising sea levels can cause a decrease in the dissolved oxygen concentration and oxidation-reduction potential of the underlying aquifer; this should increase the dissolution of insoluble arsenate (H3-xAs(V)O4x-) in sediments by reduction. This, in turn, should release soluble arsenite (H3-xAs(III)O3x-) into the drinking well water. Rising sea levels can cause an increase in the salt concentration of the underlying aquifer; this should increase the release of arsenic from sediments into the drinking well water by the salt effect.

A comprehensive survey and analysis of international drinking water regulations for inorganic chemicals with comparisons to the World Health Organization's drinking-water guidelines.

BACKGROUND: The World Health Organization (WHO) has published criteria for determining the quality of drinking water since 1958. Since 1984, these criteria were termed "guidelines" to emphasize that they are not national standards, but rather guidelines for nations to develop their own national standards, which may take into account local environmental, social, economic, and cultural conditions. When calculating guideline values (GVs), the WHO reviews the toxicological literature, calculates a health-based value (HBV), and determines whether the HBV should be adopted as a GV. The WHO also considers aesthetic aspects of drinking water quality, such as taste and the staining of plumbing fixtures, and additionally supplies aesthetic values (AVs) for certain drinking water contaminants. There is no central registry for national drinking water standards, so the degree of variation of national drinking water standards is not known. METHODS: We examined standards, guidelines, and background documents for all inorganic contaminants published by the WHO from 1958-2022. We also searched for national drinking water standards for all independent countries. RESULTS: We found the WHO currently has 16 GVs, six HBVs without GVs, and six AVs without HBVs or GVs for inorganic drinking water contaminants, excluding disinfection agents and their byproducts. More than half of the point of departure studies used to support these values were published in 2005 or earlier. Ninety-eight percent of the world's population lives in jurisdictions with drinking water standards, and 14 countries directly link their national standards to the current WHO's drinking water guidelines. Lack of transparency (standards available only through purchase) and typographical errors are common problems, especially for resource-limited countries. CONCLUSIONS: The WHO drinking water guidelines are crucially important for drinking water safety; they are used for guidance or as official standards throughout the world. It is crucial that they be based on the best available science.

Arsenic in drinking water: An analysis of global drinking water regulations and recommendations for updates to protect public health.

Evidence-based public health policy often comes years or decades after the underlying scientific breakthrough. The World Health Organization's (WHO's) provisional 10 µg/L arsenic (As) drinking water guideline was set in 1993 based on "analytical achievability." In 2011, an additional proviso of "treatment performance" was added; a health-based risk assessment would lead to a lower and more protective guideline. Since the WHO does not require United Nations member states to submit copies of national drinking water regulations, there is no complete database of national drinking water standards or guidelines. In this study, we collated and analyzed all drinking water regulations for As from national governments worldwide. We found regulations for 176 countries. Of these countries, 136 have drinking water regulations that specify 10 µg/L As or less, while 40 have regulations that allow more than 10 µg/L of As; we could not find any evidence of regulations for 19 countries. The number of people living in countries that do not meet the WHO's guideline constitutes 32% of the global population. Global As regulations are also strongly tied to national income, with high income countries more likely to meet the WHO's guideline. In this study, we examined the health risk assessments that show a clear need for reducing As exposure to levels far below the current WHO provisional guideline. We also show that advances in analytical chemistry, drinking water treatment, and the possibility of accessing alternative drinking water supplies without As suggest that both low-income countries with limited resources and high-income countries with adequate resources can adopt a lower and more protective national drinking water standards or guidelines for As. Thus, we recommend that regulators and stake holders of all nations reassess the possibilities for improving public health and reducing health care expenses by adopting more stringent regulations for As in drinking water.

How much manganese is safe for infants? A review of the scientific basis of intake guidelines and regulations relevant to the manganese content of infant formulas.

BACKGROUND: Recent research has uncovered the potential for excess manganese (Mn) intakes causing significant neurotoxic effects for early brain development. METHODS: We identified the Mn tolerable intakes (TI) published by the U.S. Institute of Medicine (IOM), World Health Organization (WHO), Agence nationale de sécurité sanitaire (ANSES), and U.S. Environmental Protection Agency (US EPA) and examined the primary studies on which regulatory TIs are based. We converted the TIs to µg of Mn/kg/day using standard assumptions specific to each agency. We estimated µg of Mn/kg/day intakes due to formulas. Using our estimates for formula intakes, weights, and kcal content, we converted regulatory maxima and minima from µg of Mn/100 kcals to estimates of µg of Mn/kg/day. RESULTS: Except for the proposed ANSES TI for drinking water, none of the primary studies on which Mn intake guidelines and regulations are based measured health outcomes. Some infant formulas may exceed the regulatory TIs, especially if prepared with water containing considerable concentrations of Mn (e.g. 250 µg/L), even while meeting national and international regulatory standards or guidelines. CONCLUSIONS: Infant formula regulations must be revised to reduce the potential for excess manganese intakes and the practice of manganese supplementation of infant formulas should be ceased.

Estimating daily intakes of manganese due to breast milk, infant formulas, or young child nutritional beverages in the United States and France: Comparison to sufficiency and toxicity thresholds.

BACKGROUND: Although manganese (Mn) is an essential nutrient, recent research has revealed that excess Mn in early childhood may have adverse effects on neurodevelopment. METHODS: We estimated daily total Mn intake due to breast milk at average body weights by reviewing reported concentrations of breast milk Mn and measurements of body weight and breast milk intake at 3 weeks, 4.25 months, 7 months, and 18 months. We compared these figures to the Mn content measured in 44 infant, follow-up, and toddler formulas purchased in the United States and France. We calculated Mn content of formula products made with ultra-trace elemental analysis grade water (0 µg Mn/L) and with water containing 250 µg Mn/L, a concentration which is relatively high but less than the World Health Organization Health-based value of 400 µg Mn/L or the United States Environmental Protection Agency Health Advisory of 350 µg Mn/L. RESULTS: Estimated mean daily Mn intake from breast milk ranged from 1.2 µg Mn/kg/day (3 weeks) to 0.16 µg Mn/kg/day (18 months), with the highest intakes at the youngest age stage we considered, 3 weeks. Estimated daily Mn intake from formula products reconstituted with 0 µg Mn/L water ranged from 130 µg Mn/kg/day (3 weeks) to 4.8 µg Mn/kg/day (18 months) with the highest intakes at 3 weeks. Formula products provided 28-520 times greater than the mean daily intake of Mn from breast milk for the 4 age stages that we considered. Estimated daily Mn intake from formula products reconstituted with water containing 250 µg Mn/L ranged from 12 µg Mn/kg/day to 170 µg Mn/kg/day, which exceeds the United States Environmental Protection Agency Reference Dose of 140 µg Mn/kg/day for adults. CONCLUSIONS: Mn deficiency is highly unlikely with exclusive breast milk or infant formula feeding, but established tolerable daily intake levels for Mn may be surpassed by some of these products when following labeled instructions.

An accurate, precise, and affordable light emitting diode spectrophotometer for drinking water and other testing with limited resources.

Spectrophotometers are commonly used to measure the concentrations of a wide variety of analytes in drinking water and other matrixes; however, many laboratories with limited resources cannot afford to buy these very useful instruments. To meet this need, an accurate, precise, and affordable light emitting diode (LED) spectrophotometer was designed and built using best engineering practices and modern circuit design. The cost and performance of this LED spectrophotometer was compared against 4 common commercial spectrophotometers. More specifically, the performance of these spectrophotometers was evaluated from the upper limits of linear range, upper limits of operational range, calibration sensitivities, R2 values, precisions of standards, estimated limits of detection, and percent calibration check standard recoveries for the determinations of iron (Fe), manganese (Mn), and fluoride (F-) in drinking water. This evaluation was done in the United States (U.S.) and India. Our LED spectrophotometer costs $63 United States Dollars (USD) for parts. The 4 commercial spectrophotometers ranged in cost from $2,424 to $7,644 USD. There are no practical differences in the upper limits of linear range, upper limits of operational range, R2 values, precisions of standards, and estimated limits of detection for our LED spectrophotometer and the 4 commercial spectrophotometers. For 2 of the 3 analytes, there is a practical difference in the calibration sensitivities our LED spectrophotometer and the 4 commercial spectrophotometers. More specifically, the calibration sensitivities for Mn and F- using our LED spectrophotometer were 65.2% and 67.0% of those using the 4 commercial spectrophotometers, respectively. In conclusion, this paper describes the design, use, and performance of an accurate, precise, and extremely affordable LED spectrophotometer for drinking water and other testing with limited resources.

Manganese levels in infant formula and young child nutritional beverages in the United States and France: Comparison to breast milk and regulations.

Exposure to high levels of manganese (Mn) in children has recently been associated with adverse neurodevelopmental effects. Current infant formula regulations for Mn content were set between 1981 (United States), 2006 (European Union, France), and 2007 (Codex Alimentarius) prior to the publication of much of the growing body of research on the developmental neurotoxicity of Mn. In this study, we sought to measure the concentrations of Mn in some infant formulas and young child nutritional beverages available on the United States (US) and French markets using ion beam analysis by particle induced X-ray emission (PIXE) spectrometry and then compare the analytical results to concentrations reported in the literature for breast milk and applicable infant formula regulations and guidelines. We were particularly interested in measuring Mn concentrations in product types for which there is very little data from previous surveys, especially soy-based, rice-based, goat-milk based, chocolate-flavored, and nutritional beverages for young children that are not regulated as infant or follow-on formulas (e.g. "toddler formulas" and "toddler powders"). We purchased 44 infant formulas and young child nutritional beverage products in the US and France with varying protein sources (cow-milk, goat-milk, soy, rice) labelled for birth to 3 years. We selected these samples using maximum variation sampling to explore market extremes to facilitate comparisons to regulatory limits. Since this sampling method is non-probabilistic, other inferences cannot be made beyond this set of samples to the overall markets. We used ion beam analysis to measure the concentrations of Mn in each product. The range of measured Mn concentrations in the products is 160-2,800 µg/L, substantially higher than the 3-6 µg/L mean Mn concentration reported in human breast milk. All products satisfied national and Codex Alimentarius Commission (CAC) international standards for minimum Mn content in infant formulas; however, 7/25 of the products purchased in the US exceeded the CAC Guidance Upper Level of 100 µg Mn/kcal for infant formula.

Rapid drinking water safety estimation in cities: Piloting a globally scalable method in Cochabamba, Bolivia.

BACKGROUND: Systematically collected and comparable data on drinking water safety at city-scale is currently unavailable, despite the stated importance of water safety monitoring at scale under the United Nations Sustainable Development Goals (SDGs). We developed a rapid drinking water quality assessment methodology intended to be replicable across all cities and useful for monitoring towards achieving SDG 6 (Clean Water and Sanitation). METHODS: We collected drinking water samples at the point-of-consumption for basic microbial, physical and chemical water quality analysis and conducted household surveys on drinking water, sanitation, and hygiene access from 80 households in the city of Cochabamba over 1 week. We categorized the household's water service level according to the SDG 6 framework. RESULTS: We estimated an average time requirement of 6.4 person-hours and a consumable cost of US $51 per household (n = 80). In this cross-sectional study, 71% of drinking water samples met World Health Organization (WHO) microbiological safety criteria, 96% met WHO chemical quality criteria, and all met WHO aesthetic quality criteria. However, only 18% of the households were categorized as having safely managed drinking water services. None met the criteria for having safely managed sanitation services; nonetheless, 81% had basic sanitation services and 78% had basic hygiene facilities. CONCLUSIONS: This method can generate basic water safety data for a city at a relatively low cost in terms of person-time and materials, yielding useful information for inter-city analyses. Because 29% of samples did not meet microbiological safety criteria, 22% of the households did not have access to handwashing facilities and none had safe sanitation services, we concluded that Cochabamba did not meet normative SDG 6 targets when surveyed. Our study further suggests that water quality at point-of-use more accurately characterizes drinking water safety than infrastructure type.

Urgent need to reevaluate the latest World Health Organization guidelines for toxic inorganic substances in drinking water.

The World Health Organization (WHO) has established guidelines for drinking-water quality that cover biological and chemical hazards from both natural and anthropogenic sources. In the most recent edition of Guidelines for Drinking-water Quality (2011), the WHO withdrew, suspended, did not establish, or raised guidelines for the inorganic toxic substances manganese, molybdenum, nitrite, aluminum, boron, nickel, uranium, mercury, and selenium. In this paper, we review these changes to the WHO drinking-water guidelines, examining in detail the material presented in the WHO background documents for each of these toxic substances. In some cases, these WHO background documents use literature reviews that do not take into account scientific research published within the last 10 or more years. In addition, there are instances in which standard WHO practices for deriving guidelines are not used; for example, rounding and other mathematical errors are made. According to published meeting reports from the WHO Chemical Aspects Working Group, the WHO has a timetable for revising some of its guidelines for drinking-water quality, but for many of these toxic substances the planned changes are minimal or will be delayed for as long as 5 years. Given the limited nature of the planned WHO revisions to the inorganic toxic substances and the extended timetable for these revisions, we suggest that governments, researchers, and other stakeholders might establish independent recommendations for inorganic toxic substances and possibly other chemicals to proactively protect public health, or at the very least, revert to previous editions of the Guidelines for Drinking-water Quality, which were more protective of public health.

World Health Organization increases its drinking-water guideline for uranium.

The World Health Organization (WHO) released the fourth edition of Guidelines for Drinking-water Quality in July, 2011. In this edition, the drinking-water guideline for uranium (U) was increased to 30 µg L(-1) despite the conclusion that "deriving a guideline value for uranium in drinking-water is complex, because the data [from exposures to humans] do not provide a clear no-effect concentration" and "Although some minor biochemical changes associated with kidney function have been reported to be correlated with uranium exposure at concentrations below 30 µg L(-1), these findings are not consistent between studies" (WHO, Uranium in Drinking-water, Background document for development of WHO Guidelines for Drinking-water Quality, available: , accessed 13 October 2011). This paper reviews the WHO drinking-water guideline for U, from its introduction as a 2 µg L(-1) health-based guideline in 1998 through its increase to a 30 µg L(-1) health-based guideline in 2011. The current 30 µg L(-1) WHO health-based drinking-water guideline was calculated using a "no-effect group" with "no evidence of renal damage [in humans] from 10 renal toxicity indicators". However, this nominal "no-effect group" was associated with increased diastolic blood pressure, systolic blood pressure, and glucose excretion in urine. In addition, the current 30 µg L(-1) guideline may not protect children, people with predispositions to hypertension or osteoporosis, pre-existing chronic kidney disease, and anyone with a long exposure. The toxic effects of U in drinking water on laboratory animals and humans justify a re-evaluation by the WHO of its decision to increase its U drinking-water guideline.

World Health Organization discontinues its drinking-water guideline for manganese.

BACKGROUND: The World Health Organization (WHO) released the fourth edition of Guidelines for Drinking-Water Quality in July 2011. In this edition, the 400-µg/L drinking-water guideline for manganese (Mn) was discontinued with the assertion that because "this health-based value is well above concentrations of manganese normally found in drinking water, it is not considered necessary to derive a formal guideline value." OBJECTIVE: In this commentary, we review the WHO guideline for Mn in drinking water--from its introduction in 1958 through its discontinuation in 2011. METHODS: For the primary references, we used the WHO publications that documented the Mn guidelines. We used peer-reviewed journal articles, government reports, published conference proceedings, and theses to identify countries with drinking water or potential drinking-water supplies exceeding 400 µg/L Mn and peer-reviewed journal articles to summarize the health effects of Mn. DISCUSSION: Drinking water or potential drinking-water supplies with Mn concentrations > 400 µg/L are found in a substantial number of countries worldwide. The drinking water of many tens of millions of people has Mn concentrations > 400 µg/L. Recent research on the health effects of Mn suggests that the earlier WHO guideline of 400 µg/L may have been too high to adequately protect public health. CONCLUSIONS: The toxic effects and geographic distribution of Mn in drinking-water supplies justify a reevaluation by the WHO of its decision to discontinue its drinking-water guideline for Mn.

Public health strategies for western Bangladesh that address arsenic, manganese, uranium, and other toxic elements in drinking water.

BACKGROUND: More than 60,000,000 Bangladeshis are drinking water with unsafe concentrations of one or more elements. OBJECTIVES: Our aims in this study were to evaluate and improve the drinking water testing and treatment plans for western Bangladesh. METHODS: We sampled groundwater from four neighborhoods in western Bangladesh to determine the distributions of arsenic, boron, barium, chromium, iron, manganese, molybdenum, nickel, lead, antimony, selenium, uranium, and zinc, and to determine pH. RESULTS: The percentages of tube wells that had concentrations exceeding World Health Organization (WHO) health-based drinking water guidelines were 78% for Mn, 48% for U, 33% for As, 1% for Pb, 1% for Ni, and 1% for Cr. Individual tube wells often had unsafe concentrations of both Mn and As or both Mn and U. They seldom had unsafe concentrations of both As and U. CONCLUSIONS: These results suggest that the ongoing program of identifying safe drinking water supplies by testing every tube well for As only will not ensure safe concentrations of Mn, U, Pb, Ni, Cr, and possibly other elements. To maximize efficiency, drinking water testing in Bangladesh should be completed in three steps: 1) all tube wells must be sampled and tested for As; 2) if a sample meets the WHO guideline for As, then it should be retested for Mn and U; 3) if a sample meets the WHO guidelines for As, Mn, and U, then it should be retested for B, Ba, Cr, Mo, Ni, and Pb. All safe tube wells should be considered for use as public drinking water supplies.

The development and use of an innovative laboratory method for measuring arsenic in drinking water from western Bangladesh.

All of Bangladesh's approximately 10 million drinking-water tube wells must be periodically tested for arsenic. The magnitude of this task and the limited resources of Bangladesh have led to the use of low-cost, semiquantitative field kits that measure As to a relatively high 50 microg/L national drinking water standard. However, there is an urgent need to supplement and ultimately replace these field kits with an inexpensive laboratory method that can measure As to the more protective 10 microg/L World Health Organization (WHO) health-based drinking water guideline. Unfortunately, Bangladesh has limited access to atomic absorption spectrometers or other expensive instruments that can measure As to the WHO guideline of 10 microg/L. In response to this need, an inexpensive and highly sensitive laboratory method for measuring As has been developed. This new method is the only accurate, precise, and safe way to quantify As < 10 microg/L without expensive or highly specialized laboratory equipment. In this method, As is removed from the sample by reduction to arsine gas, collected in an absorber by oxidation to arsenic acid, colorized by a sequential reaction to arsenomolybdate, and quantified by spectrophotometry. We compared this method with the silver diethyldithiocarbamate [AgSCSN(CH2CH3)2] and graphite furnace atomic absorption spectroscopy (GFAAS) methods for measuring As. Our method is more accurate, precise, and environmentally safe than the AgSCSN(CH2CH3)2 method, and it is more accurate and affordable than GFAAS. Finally, this study suggests that Bangladeshis will readily share drinking water with their neighbors to meet the more protective WHO guideline for As of 10 microg/L.

The concentrations of arsenic and other toxic elements in Bangladesh's drinking water.

For drinking water, the people of Bangladesh used to rely on surface water, which was often contaminated with bacteria causing diarrhea, cholera, typhoid, and other life-threatening diseases. To reduce the incidences of these diseases, millions of tubewells were installed in Bangladesh since independence in 1971. This recent transition from surface water to groundwater has significantly reduced deaths from waterborne pathogens; however, new evidence suggests disease and death from arsenic (As) and other toxic elements in groundwater are affecting large areas of Bangladesh. In this evaluation, the areal and vertical distribution of As and 29 other inorganic chemicals in groundwater were determined throughout Bangladesh. This study of 30 analytes per sample and 112 samples suggests that the most significant health risk from drinking Bangladesh's tubewell water is chronic As poisoning. The As concentration ranged from < 0.0007 to 0.64 mg/L, with 48% of samples above the 0.01 mg/L World Health Organization drinking water guideline. Furthermore, this study reveals unsafe levels of manganese (Mn), lead (Pb), nickel (Ni), and chromium (Cr). Our survey also suggests that groundwater with unsafe levels of As, Mn, Pb, Ni, and Cr may extend beyond Bangladesh's border into the four adjacent and densely populated states in India. In addition to the health risks from individual toxins, possible multimetal synergistic and inhibitory effects are discussed. Antimony was detected in 98% of the samples from this study and magnifies the toxic effects of As. In contrast, Se and Zn were below our detection limits in large parts of Bangladesh and prevent the toxic effects of As.