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.

Investigation of bone quality of the first and second sacral segments amongst trauma patients: concerns about iliosacral screw fixation.

BACKGROUND: Iliosacral screw fixation has become a common method for surgical stabilization of acute disruptions of the pelvic ring. Placement of iliosacral screws into the first sacral (S1) body is the preferred method of fixation, but size limitations and sacral dysmorphism may preclude S1 fixation. In these clinical situations, fixation into the second sacral (S2) body has been recommended. The objective of this study was to evaluate the bone quality of the S1 compared to S2 in the described "safe zone" of iliosacral screw fixation in trauma patients. MATERIALS AND METHODS: The pelvic computed tomography scans of 25 consecutive trauma patients, ages 18-49, at a level 1 trauma center were prospectively analyzed. Hounsfield units, a standardized computed tomography attenuation coefficient, was utilized to measure regional cancellous bone mineral density of the S1 and S2. No change in the clinical protocol or treatment occurred as a consequence of inclusion in this study. RESULTS: A statically significant difference in bone quality was found when comparing the first and second sacral segment (p = 0.0001). Age, gender, or smoking status did not independently affect bone quality. CONCLUSION: In relatively young, otherwise healthy trauma patients there is a statistically significant difference in the bone density of the first sacral segment compared to the second sacral segment. This study highlights the need for future biomechanical studies to investigate whether this difference is clinically relevant. Due to the relative osteopenia in the second sacral segment, which may impact the quality of fixation, we feel this technique should be used with caution.

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.

Factors associated with prevalent Mycobacterium tuberculosis infection and disease among adolescents and adults exposed to rifampin-resistant tuberculosis in the household.

BACKGROUND: Understanding factors associated with prevalent Mycobacterium tuberculosis infection and prevalent TB disease in household contacts of patients with drug-resistant tuberculosis (TB) may be useful for TB program staff conducting contact investigations. METHODS: Using data from a cross-sectional study that enrolled index participants with rifampin-resistant pulmonary TB and their household contacts (HHCs), we evaluated HHCs age ≥15 years for factors associated with two outcomes: Mycobacterium tuberculosis infection and TB disease. Among HHCs who were not already diagnosed with current active TB disease by the TB program, Mycobacterium tuberculosis infection was determined by interferon-gamma release assay (IGRA). TB disease was adjudicated centrally. We fitted logistic regression models using generalized estimating equations. RESULTS: Seven hundred twelve HHCs age ≥15 years enrolled from 279 households in eight high-TB burden countries were a median age of 34 years, 63% female, 22% current smokers and 8% previous smokers, 8% HIV-positive, and 11% previously treated for TB. Of 686 with determinate IGRA results, 471 tested IGRA positive (prevalence 68.8% (95% Confidence Interval: 64.6%, 72.8%)). Multivariable modeling showed IGRA positivity was more common in HHCs aged 25-49 years; reporting prior TB treatment; reporting incarceration, substance use, and/or a period of daily alcohol use in the past 12 months; sharing a sleeping room or more evenings spent with the index participant; living with smokers; or living in a home of materials typical of low socioeconomic status. Forty-six (6.5% (95% Confidence Interval: 4.6%, 9.0%)) HHCs age ≥15 years had prevalent TB disease. Multivariable modeling showed higher prevalence of TB disease among HHCs aged ≥50 years; reporting current or previous smoking; reporting a period of daily alcohol use in the past 12 months; and reporting prior TB treatment. CONCLUSION: We identified overlapping and distinct characteristics associated with Mycobacterium tuberculosis infection and TB disease that may be useful for those conducting household TB investigations.

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.

Drinking Water Quality and Public Health in the Kathmandu Valley, Nepal: Coliform Bacteria, Chemical Contaminants, and Health Status of Consumers.

Residents of Nepal's Kathmandu Valley draw drinking water from tube wells, dug wells, and stone spouts, all of which have been reported to have serious water quality issues. In this study, we analyzed drinking water samples from 35 tube wells, dug wells, stone spouts, and municipal tap water for bacterial and chemical contaminants, including total and fecal coliform, aluminum, arsenic, barium, beryllium, boron, cadmium, cobalt, chromium, copper, fluoride, iron, mercury, manganese, molybdenum, nickel, lead, antimony, selenium, thallium, uranium, vanadium, and zinc. We also asked a sampling of households who used these specific water sources to rate the taste of their water, list any waterborne diseases they were aware of, and share basic health information about household members. This survey provided us with information from 146 households and 603 individuals. We found widespread bacterial contamination of water sources, with 94% of sources having detectable total or fecal coliform. Nepal Drinking Water Quality Standards and World Health Organization (WHO) Drinking-Water Guidelines or health-based values were exceeded for aluminum (max = 0.53 mg/L), arsenic (max = 0.071 mg/L), iron (max = 7.22 mg/L), and manganese (max = 3.229 mg/L). The distribution of water sources with high arsenic, iron, and manganese appeared to be associated with floodplain deposits. Mixed effects logistic regression models were used to examine the interactions between social factors and water contaminants and their effects on household members' health. Consumers of water sources with both high and low concentrations of manganese were less likely to have a positive attitude towards school than those whose water sources had moderate concentrations of manganese. Social factors, especially education, played a large role in predicting individual health outcomes. Household taste ratings of drinking water were not correlated with iron or manganese concentrations, suggesting that WHO's reliance on aesthetic criteria for these contaminants instead of formal drinking-water guidelines may not be sufficient to protect public health.

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.

Fourteen polymorphic microsatellite markers for the widespread Labrador tea (Rhododendron groenlandicum).

PREMISE: Microsatellite markers were developed for Labrador tea (Rhododendron groenlandicum, Ericaceae) to facilitate downstream genetic investigation of this species and the extremely closely related, circumboreal Rhododendron subsect. Ledum. METHODS AND RESULTS: Forty-eight primer pairs were designed using Illumina data and screened for excellent amplification. Sixteen successful pairs were developed as microsatellite markers using fluorescently labeled amplification to generate chromatogram data. These data were evaluated for intrapopulation and interpopulation variability in three populations from Alaska and Maine, USA, and the Northwest Territories, Canada. Fourteen polymorphic markers genotyped reliably, each with one to eight alleles. Cluster analysis indicates that across the range, populations can be easily discriminated. Cross-amplification in other Rhododendron subsect. Ledum species shows broad application of the developed markers within this small, well-supported clade. CONCLUSIONS: These microsatellite markers exhibit significant variability and will be useful in population genetics within R. groenlandicum and for investigation of species boundaries across Rhododendron subsect. Ledum.

Fifteen microsatellite markers for the Appalachian rockcap fern, Polypodium appalachianum (Polypodiaceae), and its relatives.

PREMISE OF THE STUDY: Microsatellite markers were developed for Polypodium appalachianum (Polypodiaceae) to facilitate investigation of species boundaries between P. appalachianum and its putative hybrid, P. virginianum, and potentially among other members of the Miocene-age P. vulgare species complex. METHODS AND RESULTS: Forty-eight primer pairs were designed from Illumina data and screened for successful amplification. Sixteen pairs were genotyped and evaluated for variability within and among three populations in North Carolina, Vermont, and New Hampshire. Twelve of these primer pairs were reliable and polymorphic, exhibiting one to 10 alleles per locus. Cross-species amplification experiments were conducted for P. virginianum and four additional close relatives from the P. vulgare complex in order to maximize information about likely utility within a phylogenetic context. CONCLUSIONS: These microsatellite markers will be useful in population genetics and species boundaries studies of P. appalachianum and P. virginianum, and likely in other species within the P. vulgare complex.

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.

Multiple inorganic toxic substances contaminating the groundwater of Myingyan Township, Myanmar: arsenic, manganese, fluoride, iron, and uranium.

In South Asia, the technological and societal shift from drinking surface water to groundwater has resulted in a great reduction of acute diseases due to water borne pathogens. However, arsenic and other naturally occurring inorganic toxic substances present in groundwater in the region have been linked to a variety of chronic diseases, including cancers, heart disease, and neurological problems. Due to the highly specific symptoms of chronic arsenic poisoning, arsenic was the first inorganic toxic substance to be noticed at unsafe levels in the groundwater of West Bengal, India and Bangladesh. Subsequently, other inorganic toxic substances, including manganese, uranium, and fluoride have been found at unsafe levels in groundwater in South Asia. While numerous drinking water wells throughout Myanmar have been tested for arsenic, relatively little is known about the concentrations of other inorganic toxic substances in Myanmar groundwater. In this study, we analyzed samples from 18 drinking water wells (12 in Myingyan City and 6 in nearby Tha Pyay Thar Village) and 2 locations in the Ayeyarwaddy River for arsenic, boron, barium, beryllium, cadmium, cobalt, chromium, copper, fluoride, iron, mercury, manganese, molybdenum, nickel, lead, antimony, selenium, thallium, uranium, vanadium, and zinc. Concentrations of arsenic, manganese, fluoride, iron, or uranium exceeded health-based reference values in most wells. In addition, any given well usually contained more than one toxic substance at unsafe concentrations. While water testing and well sharing could reduce health risks, none of the wells sampled provide water that is entirely safe with respect to inorganic toxic substances. It is imperative that users of these wells, and users of other wells that have not been tested for multiple inorganic toxic substances throughout the region, be informed of the need for drinking water testing and the health consequences of drinking water contaminated with inorganic toxic substances.

The effect of gamma radiation sterilization on the fatigue crack propagation resistance of human cortical bone.

BACKGROUND: Clinical evidence has suggested that the rate of fracture in allografts sterilized with gamma radiation may be higher than that in controls. Gamma radiation sterilization has been shown to affect the post-yield properties of bone but not the elastic modulus. Since most allograft fractures occur with subcritical loads during activities of daily living, it may be that the fatigue properties of irradiated allografts are diminished. In this study, the fatigue crack propagation behavior of cortical bone sterilized with gamma radiation was compared with that of gender and age-matched controls. We hypothesized that gamma radiation significantly reduces the resistance of cortical bone to fatigue crack growth. METHODS: Specimens for fatigue crack propagation testing were machined from four pairs of fresh-frozen human femora obtained from four individuals (a younger male, younger female, older male, and older female donor). Half of the specimens were sterilized with 31.7 kGy of gamma radiation. The specimens were cyclically loaded to failure in a servohydraulic testing system, and crack growth was monitored. The cyclic stress intensity factor and the fatigue crack growth rate were calculated to examine the kinetics of fatigue crack growth. Following testing, the damage zone around the fracture plane was analyzed histologically. RESULTS: The morphology and kinetics of crack growth in irradiated specimens differed from the control data. Overall, the irradiated bone was significantly less resistant to fatigue crack growth than was control tissue (p < 0.05). There was less microdamage associated with fracture in the irradiated specimens than in the control specimens, with the exception of the bone from the older female donor. CONCLUSIONS: Gamma radiation sterilization significantly reduces the fatigue crack propagation resistance of cortical bone. Irradiated specimens also demonstrate a smaller amount of microdamage along the fracture plane. These findings may be due to ultrastructural alterations in the collagen matrix caused by radiation. CLINICAL RELEVANCE: This study suggests that, despite having pre-yield mechanical properties that are similar to those of nonirradiated bone, gamma-radiation-sterilized allograft may be more predisposed to fracture even under the subcritical loads that occur during the activities of daily living.

Variability in Accreditation Council for Graduate Medical Education Resident Case Log System practices among orthopaedic surgery residents.

BACKGROUND: The Accreditation Council for Graduate Medical Education (ACGME) Resident Case Log System is designed to be a reflection of residents' operative volume and an objective measure of their surgical experience. All operative procedures and manipulations in the operating room, Emergency Department, and outpatient clinic are to be logged into the Resident Case Log System. Discrepancies in the log volumes between residents and residency programs often prompt scrutiny. However, it remains unclear if such disparities truly represent differences in operative experiences or if they are reflections of inconsistent logging practices. The purpose of this study was to investigate individual recording practices among orthopaedic surgery residents prior to August 1, 2011. METHODS: Orthopaedic surgery residents received a questionnaire on case log practices that was distributed through the Council of Orthopaedic Residency Directors list server. Respondents were asked to respond anonymously about recording practices in different clinical settings as well as types of cases routinely logged. Hypothetical scenarios of common orthopaedic procedures were presented to investigate the differences in the Current Procedural Terminology codes utilized. RESULTS: Two hundred and ninety-eight orthopaedic surgery residents completed the questionnaire; 37% were fifth-year residents, 22% were fourth-year residents, 18% were third-year residents, 15% were second-year residents, and 8% were first-year residents. Fifty-six percent of respondents reported routinely logging procedures performed in the Emergency Department or urgent care setting. Twenty-two percent of participants routinely logged procedures in the clinic or outpatient setting, 20% logged joint injections, and only 13% logged casts or splints applied in the office setting. There was substantial variability in the Current Procedural Terminology codes selected for the seven clinical scenarios. CONCLUSIONS: There has been a lack of standardization in case-logging practices among orthopaedic surgery residents prior to August 1, 2011. ACGME case log data prior to this date may not be a reliable measure of residents' procedural experience.

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.

A survey of arsenic, manganese, boron, thorium, and other toxic metals in the groundwater of a West Bengal, India neighbourhood.

Around 150 million people are at risk from arsenic-contaminated groundwater in India and Bangladesh. Multiple metal analysis in Bangladesh has found other toxic elements above the World Health Organization (WHO) health-based drinking water guidelines which significantly increases the number of people at risk due to drinking groundwater. In this study, drinking water samples from the Bongaon area (North 24 Parganas district, West Bengal, India) were analyzed for multiple metal contamination in order to evaluate groundwater quality on the neighbourhood scale. Each sample was analyzed for arsenic (As), boron (B), barium (Ba), chromium (Cr), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), and uranium (U). Arsenic was found above the WHO health-based drinking water guideline in 50% of these tubewells. Mn and B were found at significant concentrations in 19% and 6% of these tubewells, respectively. The maps of As, Mn, and B concentrations suggest that approximately 75% of this area has no safe tubewells. The concentrations of As, Mn, B, and many other toxic elements are independent of each other. The concentrations of Pb and U were not found above WHO health-based drinking water guidelines but they were statistically related to each other (p-value = 0.001). An analysis of selected isotopes in the Uranium, Actinium, and Thorium Radioactive Decay Series revealed the presence of thorium (Th) in 31% of these tubewells. This discovery of Th, which does not have a WHO health-based drinking water guideline, is a potential public health challenge. In sum, the widespread presence and independent distribution of other metals besides As must be taken into consideration for drinking water remediation strategies involving well switching or home-scale water treatment.