The global roots of pre-1900 legacy mercury.

During the nineteenth century, a major change took place in the trade, production, and use of mercury that altered its nearly exclusive link to silver refining in the Hispanic New World. We track the global expansion of mercury markets in chronological detail from 1511 to 1900 using historical archives on production and trade, a detailed country-by-country accounting of the pool of anthropogenic mercury from which legacy mercury was ultimately generated. The nature and profile of pre-1900 legacy mercury extends beyond silver refining, mercury production, and gold extraction, and includes alternate sources (vermilion, felt, mercury fulminate) and new regions that were not major silver or gold producers (China, India, United Kingdom, France, among others), that accounted for approximately 50% of total mercury consumed in the nineteenth century. The nature of the pre-1900 mercury market requires a quantitative distinction between legacy mercury and historic anthropogenic mercury production and use, since the chemistry of its end-uses determines the pathways and timelines for its incorporation into the global biogeochemical cycle. We thus introduce the concept of a mercury source pool to account for total historic anthropogenic mercury within and outside this cycle. Together with a critical review of previous assumptions used to reconstruct the historical use and loss of mercury, a much lower level of emissions of pre-1900 legacy mercury is proposed. A coordinated effort across disciplines is needed, to complete a historically accurate scenario that can guide the multilateral policies adopted under the United Nations Minamata Convention to control mercury in the environment.

Anthropometric deficits and the associated risk of death by age and sex in children aged 6-59 months: A meta-analysis.

Risk of death from undernutrition is thought to be higher in younger than in older children, but evidence is mixed. Research also demonstrates sex differences whereby boys have a higher prevalence of undernutrition than girls. This analysis described mortality risk associated with anthropometric deficits (wasting, underweight and stunting) in children 6-59 months by age and sex. We categorised children into younger (6-23 months) and older (24-59 months) age groups. Age and sex variations in near-term (within 6 months) mortality risk, associated with individual anthropometric deficits were assessed in a secondary analysis of multi-country cohort data. A random effects meta-analysis was performed. Data from seven low-or-middle-income-countries collected between 1977 and 2013 were analysed. One thousand twenty deaths were recorded for children with anthropometric deficits. Pooled meta-analysis estimates showed no differences by age in absolute mortality risk for wasting (RR 1.08, p = 0.826 for MUAC < 125 mm; RR 1.35, p = 0.272 for WHZ < -2). For underweight and stunting, absolute risk of death was higher in younger (RR 2.57, p < 0.001) compared with older children (RR 2.83, p < 0.001). For all deficits, there were no differences in mortality risk for girls compared with boys. There were no differences in the risk of mortality between younger and older wasted children, supporting continued inclusion of all children under-five in wasting treatment programmes. The risk of mortality associated with underweight and stunting was higher among younger children, suggesting that prevention programmes might be justified in focusing on younger children where resources are limited. There were no sex differences by age in mortality risk for all deficits.

Effectiveness of management of severe acute malnutrition (SAM) through community health workers as compared to a traditional facility-based model: a cluster randomized controlled trial.

PURPOSE: We compared the impact of management of severe acute malnutrition (SAM) by lady health workers (LHWs) at a community level with the standard CMAM program provided at the health facility. METHODS: A two-arm cluster randomised controlled trial was conducted in a rural district in sindh Pakistan. The primary outcome was recovery from SAM and secondary outcomes were relapse, defaulter and mortality rate. RESULTS: A total of 829 children were recruited in the trial (430 in intervention and 399 in control groups). No significant difference was noted in recovery rate between the intervention and control groups (79.2% vs 85.6%, p = 0.276). Similarly, no significant differences were noted in relapse (p = 0.757), weight gain (p = 0.609), deaths (p = 0.775) and defaulter rate (p = 0.324) across the groups. Compliance of RUTF was significantly higher in the control group (93%) than in the intervention group (87%), p < 0.000. CONCLUSION: Our results showed no impact of SAM treatment on performance indicators of CMAM (recovery, relapse, death and default) between the standard CMAM programme performed at the health facility by the government and NGO staff and the programme performed at health house level by the LHWs in Pakistan. We recommend further robust trials in other settings to confirm our results.

Evaluation of the cost-effectiveness of the treatment of uncomplicated severe acute malnutrition by lady health workers as compared to an outpatient therapeutic feeding programme in Sindh Province, Pakistan.

BACKGROUND: Due to the limited evidence of the cost-effectiveness of Community Health Workers (CHW) delivering treatment for severe acute malnutrition (SAM), there is a need to better understand the costs incurred by both implementing institutions and beneficiary households. This study assessed the costs and cost-effectiveness of treatment for cases of SAM without complications delivered by government-employed Lady Health Workers (LHWs) and complemented with non-governmental organisation (NGO) delivered outpatient facility-based care compared with NGO delivered outpatient facility-based care only alongside a two-arm randomised controlled trial conducted in Sindh Province, Pakistan. METHODS: An activity-based cost model was used, employing a societal perspective to include costs incurred by beneficiaries and the wider community. Costs were estimated through accounting records, interviews and informal group discussions. Cost-effectiveness was assessed for each arm relative to no intervention, and incrementally between the two interventions, providing information on both absolute and relative costs and effects. RESULTS: The cost per child recovered in outpatient facility-based care was similar to LHW-delivered care, at 363 USD and 382 USD respectively. An additional 146 USD was spent per additional child recovered by outpatient facilities compared to LHWs. Results of sensitivity analyses indicated considerable uncertainty in which strategy was most cost-effective due to small differences in cost and recovery rates between arms. The cost to the beneficiary household of outpatient facility-based care was double that of LHW-delivered care. CONCLUSIONS: Outpatient facility-based care was found to be slightly more cost-effective compared to LHW-delivered care, despite the potential for cost-effectiveness of CHWs managing SAM being demonstrated in other settings. The similarity of cost-effectiveness outcomes between the two models resulted in uncertainty as to which strategy was the most cost-effective. Similarity of costs and effectiveness between models suggests that whether it is appropriate to engage LHWs in substituting or complementing outpatient facilities may depend on population needs, including coverage and accessibility of existing services, rather than be purely a consideration of cost. Future research should assess the cost-effectiveness of LHW-delivered care when delivered solely by the government. TRIAL REGISTRATION: NCT03043352 , ClinicalTrials.gov. Retrospectively registered.

Interactions between thermoregulatory behavior and physiological acclimatization in a wild lizard population.

Although the importance of thermoregulation and plasticity as compensatory mechanisms for climate change has long been recognized, they have largely been studied independently. Thus, we know comparatively little about how they interact to shape physiological variation in natural populations. Here, we test the hypothesis that behavioral thermoregulation and thermal acclimatization interact to shape physiological phenotypes in a natural population of the diurnal lizard, Sceloporus torquatus. Every month for one year we examined thermoregulatory effectiveness and changes in the population mean in three physiological parameters: cold tolerance (Ctmin), heat tolerance (Ctmax), and the preferred body temperature (Tpref), to indirectly assess thermal acclimatization in population means. We discovered that S. torquatus is an active thermoregulator throughout the year, with body temperature varying little despite strong seasonal temperature shifts. Although we did not observe a strong signal of acclimatization in Ctmax, we did find that Ctmin shifts in parallel with nighttime temperatures throughout the year. This likely occurs, at least in part, because thermoregulation is substantially less effective at buffering organisms from selection on lower physiological limits than upper physiological limits. Active thermoregulation is effective at limiting exposure to extreme temperatures during the day, but is less effective at night, potentially contributing to greater plasticity in Ctmin than Ctmax. Importantly, however, Tpref tracked seasonal changes in temperature, which is one the factors contributing to highly effective thermoregulation throughout the year. Thus, behavior and physiological plasticity do not always operate independently, which could impact how organisms can respond to rising temperatures.

Can community health workers manage uncomplicated severe acute malnutrition? A review of operational experiences in delivering severe acute malnutrition treatment through community health platforms.

Community health workers (CHWs) play an important role in the detection and referral of children with severe acute malnutrition (SAM) in many countries. However, distance to health facilities remains a significant obstacle for caregivers to attend treatment services, resulting in SAM treatment coverage rates below 40% in most areas of intervention. The inclusion of SAM treatment into the current curative tasks of CHWs has been proposed as an approach to increase coverage. A literature review of operational experiences was conducted to identify opportunities and challenges associated with this model. A total of 18 studies providing evidence on coverage, clinical outcomes, quality of care, and/or cost-effectiveness were identified. The studies demonstrate that CHWs can identify and treat uncomplicated cases of SAM, achieving cure rates above the minimum standards and reducing default rates to less than 8%. Although the evidence is limited, these findings suggest that early detection and treatment in the community can increase coverage of SAM in a cost-effective manner. Adequate training and close supervision were found to be essential to ensure high-quality performance of CHWs. Motivation through financial compensation and other incentives, which improve their social recognition, was also found to be an important factor contributing to high-quality performance. Another common challenge affecting performance is insufficient stock of key commodities (i.e., ready-to-use therapeutic food). The review of the evidence ultimately demonstrates that the successful delivery of SAM treatment via CHWs will require adaptations in nutrition and health policy and practice.

Cost-effectiveness of the treatment of uncomplicated severe acute malnutrition by community health workers compared to treatment provided at an outpatient facility in rural Mali.

BACKGROUND: The Malian Nutrition Division of the Ministry of Health and Action Against Hunger tested the feasibility of integrating treatment of severe acute malnutrition (SAM) into the existing Integrated Community Case Management package delivered by community health workers (CHWs). This study assessed costs and cost-effectiveness of CHW-delivered care compared to outpatient facility-based care. METHODS: Activity-based costing methods were used, and a societal perspective employed to include all relevant costs incurred by institutions, beneficiaries and communities. The intervention and control arm enrolled different numbers of children so a modelled scenario sensitivity analysis was conducted to assess the cost-effectiveness of the two arms, assuming equal numbers of children enrolled. RESULTS: In the base case, with unequal numbers of children in each arm, for CHW-delivered care, the cost per child treated was 244 USD and cost per child recovered was 259 USD. Outpatient facility-based care was less cost-effective at 442 USD per child and 501 USD per child recovered. The conclusions of the analysis changed in the modelled scenario sensitivity analysis, with outpatient facility-based care being marginally more cost-effective (cost per child treated is 188 USD, cost per child recovered is 214 USD), compared to CHW-delivered care. This suggests that achieving good coverage is a key factor influencing cost-effectiveness of CHWs delivering treatment for SAM in this setting. Per week of treatment, households receiving CHW-delivered care spent half of the time receiving treatment and three times less money compared with those receiving treatment from the outpatient facility. CONCLUSIONS: This study supports existing evidence that the delivery of treatment by CHWs is a cost-effective intervention, provided that good coverage is achieved. A major benefit of this strategy was the lower cost incurred by the beneficiary household when treatment is available in the community. Further research is needed on the implementation costs that would be incurred by the government to increase the operability of these results.

Quality of care of treatment for uncomplicated severe acute malnutrition provided by lady health workers in Pakistan.

OBJECTIVE: To assess the quality of care provided by lady health workers (LHW) managing cases of uncomplicated severe acute malnutrition (SAM) in the community. DESIGN: Cross-sectional quality-of-care study. SETTING: The feasibility of the implementation of screening and treatment for uncomplicated SAM in the community by LHW was tested in Sindh Province, Pakistan. An observational, clinical prospective multicentre cohort study compared the LHW-delivered care with the existing outpatient health facility model. SUBJECTS: LHW implementing treatment for uncomplicated SAM in the community. RESULTS: Oedema was diagnosed conducted correctly for 87·5 % of children; weight and mid upper-arm circumference were measured correctly for 60·0 % and 57·4 % of children, respectively. The appetite test was conducted correctly for 42·0 % of cases. Of all cases of SAM without complications assessed during the study, 68·0 % received the correct medical and nutrition treatment. The proportion of cases that received the correct medical and nutrition treatment and key counselling messages was 4·0 %. CONCLUSIONS: This quality-of-care study supports existing evidence that LHW are able to identify uncomplicated SAM, and a majority can provide appropriate nutrition and medical treatment in the community. However, the findings also show that their ability to provide the complete package with an acceptable level of care is not assured. Additional evidence on the impact of supervision and training on the quality of SAM treatment and counselling provided by LHW to children with SAM is required. The study has also shown that, as in other sectors, it is essential that operational challenges are addressed in a timely manner and that implementers receive appropriate levels of support, if SAM is to be treated successfully in the community.

Quality of care for treatment of uncomplicated severe acute malnutrition delivered by community health workers in a rural area of Mali.

An alternative Community-based Management of Acute Malnutrition model with community health workers (CHWs) delivering treatment for uncomplicated severe acute malnutrition (SAM) was piloted in Mali. The capacity of the CHWs to evaluate, classify, and treat cases of uncomplicated SAM, to provide nutritional counselling to caretakers of children receiving treatment for SAM, malaria, pneumonia or diarrhoea and to correctly refer cases of complicated SAM, was assessed. This was done using direct observation by trained enumerators of the management of SAM cases using checklists, re-diagnosing the cases admitted for treatment and reviewing admissions cards and registers. One hundred twenty-five cases, assessed and treated by the CHWs, were observed. The majority of children were correctly assessed for the presence of major clinical signs (cough, diarrhoea, fever, and vomiting; 97.6%), and similarly most children were checked for the presence of danger signs (95.2%). Mid-upper arm circumference was correctly assessed in 96.8% of children and oedema was correctly assessed in 78.4% (The composite indicator, which includes all essential tasks to provide high-quality treatment, was achieved in 79.5% of cases. This paper concludes that well-trained and supervised CHWs are capable of managing cases of uncomplicated SAM. This suggests that such a strategy is an opportunity to increase access to quality treatment in Mali for SAM cases. However, further evidence is required to ensure that this level of care can be achieved at scale.

Barriers to access for severe acute malnutrition treatment services in Pakistan and Ethiopia: a comparative qualitative analysis.

OBJECTIVE: To understand and compare the primary barriers households face when accessing treatment for cases of childhood severe acute malnutrition (SAM) in different cultural settings with different types of implementing agencies. DESIGN: The study presents a comparative qualitative analysis of two SAM treatment services, selected to include: (i) one programme implemented by a non-governmental organization and one by a Ministry of Health; and (ii) programmes considered to be successful, defined as either coverage level achieved or extent of integration within government infrastructure. Results from individual interviews and group discussions were recorded and analysed for themes in barriers to access. SETTING: Sindh Province, Pakistan; Tigray Region, Ethiopia. SUBJECTS: Beneficiary communities and staff of SAM treatment services in two countries. RESULTS: Common barriers were related to distance, high opportunity costs, knowledge of services, knowledge of malnutrition and child's refusal of ready-to-use foods. While community sensitization mechanisms were generally strong in these well-performing programmes, in remote areas with less programme exposure, beneficiaries experienced barriers to remaining in the programme until their children recovered. CONCLUSIONS: Households experienced a number of barriers when accessing SAM treatment services. Integration of SAM treatment with other community-based interventions, as the UN recommends, can improve access to life-saving services. Efforts to integrate SAM treatment into national health systems should not neglect the community component of health systems and dedicated funding for the community component is needed to ensure access. Further research and policy efforts should investigate feasible mechanisms to effectively reduce barriers to access and ensure equitable service delivery.

Effectiveness of decentralizing outpatient acute malnutrition treatment with community health workers and a simplified combined protocol: a cluster randomized controlled trial in emergency settings of Mali.

Background: Outpatient treatment of acute malnutrition is usually centralized in health centers and separated into different programs according to case severity. This complicates case detection, care delivery, and supply chain management, making it difficult for families to access treatment. This study assessed the impact of treating severe and moderate cases in the same program using a simplified protocol and decentralizing treatment outside health centers through community health workers (CHWs). Methods: A three-armed cluster randomized controlled trial under a non-inferiority hypothesis was conducted in the Gao region of Mali involving 2,038 children between 6 and 59 months of age with non-complicated acute malnutrition. The control arm consisted of 549 children receiving standard treatment in health centers from nursing staff. The first intervention arm consisted of 800 children treated using the standard protocol with CHWs added as treatment providers. The second intervention arm consisted of 689 children treated by nurses and CHWs under the ComPAS simplified protocol, considering mid-upper arm circumference as the sole anthropometric criterion for admission and discharge and providing a fixed dose of therapeutic food for severe and moderate cases. Coverage was assessed through cross-sectional surveys using the sampling evaluation of access and coverage (SLEAC) methodology for a wide area involving several service delivery units. Results: The recovery rates were 76.3% in the control group, 81.8% in the group that included CHWs with the standard protocol, and 92.9% in the group that applied the simplified protocol, confirming non-inferiority and revealing a significant risk difference among the groups. No significant differences were found in the time to recovery (6 weeks) or in anthropometric gain, whereas the therapeutic food expenditure was significantly lower with the simplified combined program in severe cases (43 sachets fewer than the control). In moderate cases, an average of 35 sachets of therapeutic food were used. With the simplified protocol, the CHWs had 6% discharge errors compared with 19% with the standard protocol. The treatment coverage increased significantly with the simplified combined program (SAM +42.5%, MAM +13.8%). Implications: Implementing a simplified combined treatment program and adding CHWs as treatment providers can improve coverage while maintaining non-inferior effectiveness, reducing the expenditure on nutritional intrants, and ensuring the continuum of care for the most vulnerable children.

Viviparity imparts a macroevolutionary signature of ecological opportunity in the body size of female Liolaemus lizards.

Viviparity evolved ~115 times across squamate reptiles, facilitating the colonization of cold habitats, where oviparous species are scarce or absent. Whether the ecological opportunity furnished by such colonization reconfigures phenotypic diversity and accelerates evolution is unclear. We investigated the association between viviparity and patterns and rates of body size evolution in female Liolaemus lizards, the most species-rich tetrapod genus from temperate regions. Here, we discover that viviparous species evolve ~20% larger optimal body sizes than their oviparous relatives, but exhibit similar rates of body size evolution. Through a causal modeling approach, we find that viviparity indirectly influences body size evolution through shifts in thermal environment. Accordingly, the colonization of cold habitats favors larger body sizes in viviparous species, reconfiguring body size diversity in Liolaemus. The catalyzing influence of viviparity on phenotypic evolution arises because it unlocks access to otherwise inaccessible sources of ecological opportunity, an outcome potentially repeated across the tree of life.

Comparison of hydric and thermal physiology in an environmentally diverse clade of Caribbean anoles.

As the world becomes warmer and precipitation patterns less predictable, organisms will experience greater heat and water stress. It is crucial to understand the factors that predict variation in thermal and hydric physiology among species. This study focuses on investigating the relationships between thermal and hydric diversity, and their environmental predictors, in a clade of Hispaniolan anole lizards, which are part of a broader Caribbean adaptive radiation. This clade, the 'cybotoid' anoles, occupies a wide range of thermal habitats (from sea level to several kilometers above it) and hydric habitats (such as xeric scrub, broadleaf forest, and pine forest), setting up the possibility for ecophysiological specialization among species. Among the thermal traits only cold tolerance is correlated with environmental temperature, and none of our climate variables were correlated with hydric physiology. Nevertheless, we found a negative relationship between heat tolerance (critical thermal maximum) and evaporative water loss at higher temperatures such that more heat tolerant lizards are also more desiccation tolerant at higher temperatures. This finding hints at shared thermal and hydric specialization at higher temperatures, underscoring the importance of considering the interactive effects of temperature and water balance in ecophysiological studies. While ecophysiological differentiation is a core feature of the anole adaptive radiation, our results suggest that close relatives in this lineage do not diverge in hydric physiology and only diverge partially in thermal physiology.

Silver refining in the New World: A singularity in the history of useful knowledge.

Historians have thoroughly documented the development of mercury-based silver refining in Spanish America in the late sixteenth century, and its use for over 300 years on an industrial scale unknown in Europe. However, we currently lack any consensus about the significance of this technology in the global history of knowledge. This article critically reassesses the invention and improvement of this refining method with the aim of addressing two interrelated issues. Firstly, how experiential knowledge and practical skills in silver refining were deliberately harnessed to solve a specific technical problem. Secondly, how economic incentives and patronage set the stage for empirical practices and a collaborative culture that facilitated the widespread use of this novel technique. In so doing, this article places silver refining within the theoretical constructs and historiography of useful knowledge, and bridges narratives that have remained largely isolated.

A synthesis of mercury research in the Southern Hemisphere, part 2: Anthropogenic perturbations.

Environmental mercury (Hg) contamination is a global concern requiring action at national scales. Scientific understanding and regulatory policies are underpinned by global extrapolation of Northern Hemisphere Hg data, despite historical, political, and socioeconomic differences between the hemispheres that impact Hg sources and sinks. In this paper, we explore the primary anthropogenic perturbations to Hg emission and mobilization processes that differ between hemispheres and synthesize current understanding of the implications for Hg cycling. In the Southern Hemisphere (SH), lower historical production of Hg and other metals implies lower present-day legacy emissions, but the extent of the difference remains uncertain. More use of fire and higher deforestation rates drive re-mobilization of terrestrial Hg, while also removing vegetation that would otherwise provide a sink for atmospheric Hg. Prevalent Hg use in artisanal and small-scale gold mining is a dominant source of Hg inputs to the environment in tropical regions. Meanwhile, coal-fired power stations continue to be a significant Hg emission source and industrial production of non-ferrous metals is a large and growing contributor. Major uncertainties remain, hindering scientific understanding and effective policy formulation, and we argue for an urgent need to prioritize research activities in under-sampled regions of the SH.

Effectiveness and Coverage of Severe Acute Malnutrition Treatment with a Simplified Protocol in a Humanitarian Context in Diffa, Niger.

BACKGROUND: the aim of this study is to evaluate the effectiveness and coverage of a simplified protocol that is implemented in health centers (HCs) and health posts (HPs) for children who are suffering from severe acute malnutrition (SAM) in the humanitarian context of Diffa. METHODS: We conducted a non-randomized community-controlled trial. The control group received outpatient treatment for SAM, without medical complications, at HCs and HPs with the standard protocol of community management of acute malnutrition (CMAM). Meanwhile, with respect to the intervention group, the children with SAM received treatment at the HCs and HPs through a simplified protocol wherein the mid-upper arm circumference (MUAC) and the presence of edema were used as the admission criteria, and the children with SAM were administered doses of fixed ready-to-use therapeutic food (RUTF). RESULTS: A total of 508 children, who were all under 5 years and had SAM, were admitted into the study. The cured proportion was 87.4% in the control group versus 96.6% in the intervention group (p value = 0.001). There was no difference between the groups in the length of stay, which was 35 days, but the intervention group used a lower quantity of RUTF-70 sachets versus 90 sachets, per child cured. Coverage increases were observed in both groups. DISCUSSION: the simplified protocol used at the HCs and HPs did not result in worse recovery and resulted in fewer discharge errors compared to the standard protocol.

A qualitative investigation of adherence to nutritional therapy in malnourished adult AIDS patients in Kenya.

OBJECTIVE: To understand factors affecting the compliance of malnourished, HIV-positive adults with a nutritional protocol using ready-to-use therapeutic food (RUTF; Plumpy'nut®). DESIGN: Qualitative study using key informant interviews, focus group discussions and direct observations. SETTING: Ministry of Health HIV/programme supported by Médecins Sans Frontièrs (MSF) in Nyanza Province, Kenya. SUBJECTS: Adult patients (n 46) currently or previously affected by HIV-associated wasting and receiving anti-retroviral therapy, their caregivers (n 2) and MoH/MSF medical employees (n 8). RESULTS: Thirty-four out of forty-six patients were receiving RUTF (8360 kJ/d) at the time of the study and nineteen of them were wasted (BMI < 17 kg/m2). Six of the thirteen wasted out-patients came to the clinic without a caregiver and were unable to carry their monthly provision (12 kg) of RUTF home because of physical frailty. Despite the patients' enthusiasm about their weight gain and rapid resumption of labour activities, the taste of the product, diet monotony and clinical conditions associated with HIV made it impossible for half of them to consume the daily prescription. Sharing the RUTF with other household members and mixing with other foods were common. Staff training did not include therapeutic dietetic counselling. CONCLUSIONS: The level of reported compliance with the prescribed dose of RUTF was low. An improved approach to treating malnourished HIV-positive adults in limited resource contexts is needed and must consider strategies to support patients without a caregiver, development of therapeutic foods more suited to adult taste, specific dietetic training for health staff and the provision of liquid therapeutic foods for severely ill patients.

Child wasting before and after age two years: A cross-sectional study of 94 countries.

Background: Wasting reflects infections and poor nutrition and affects almost 50 million children at any given time. Wasting comes with immediate risk of mortality and increased risks for long-term negative consequences for development. Children under two are particularly sensitive to undernutrition and infections. We estimated the age patterning in wasting prevalence. Methods: We calculated wasting prevalence and used Poisson regression models to estimate prevalence ratios comparing prevalence in children under and over two years using data from Demographic and Health Surveys and Multiple Indicator Cluster Surveys from 94 mostly low- and middle-income countries, including 804,172 children under five, born to a nationally representative sample of women 15-49 years old. Wasting prevalence was defined as the percentage of children with weight-for-height below -2 z-score from the median of the WHO 2006 growth standard. Findings: Wasting prevalence for children under two was 14% (95% CI: 13, 14) while it was 9% (95% CI: 9, 9) for children 2-4 years old-leading to a prevalence ratio of 0·66 (95% CI: 0·64, 0·67) in our pooled sample. Prevalence ratios were less than one, indicating lower prevalence in children over two, in 87 countries and statistically significantly lower than one at a 5% level (non-adjusted) in 68 countries. Wasting prevalence was generally lower in children under two for males and females and the wealthiest and poorest households. Interpretation: Since wasting prevalence was observed to be greater among children 0-2 years, and adverse exposure to undernutrition and infections are particularly harmful and interventions are more effective during the 1000 days from conception until age two, nutrition interventions should ensure coverage of children under two through programmatic measures to increase detection and enrollment in wasting programs. Funding: UNICEF, Nutrition Section, Programme Division in New York.

Widespread elevated concentrations of gaseous elemental mercury in Guanajuato, Mexico, centuries after historical silver refining by mercury amalgamation.

Silver (Ag) production in Hispanic America between the 16th and 19th centuries is thought to be one of the largest sources of anthropogenic mercury (Hg) emissions in history. Recent reviews of the chemistry behind the patio process, which used Hg amalgamation to extract Ag from ore, reveal that a large amount of the Hg may not have been immediately released to the atmosphere; instead, it may have been captured in the form of calomel (Hg2Cl2, in which Hg exists as monovalent HgI) and remained in the local environment. Here we show that Hg used in the patio process centuries ago in the Guanajuato Mining District of Mexico continues to elevate present-day concentrations of gaseous elemental mercury (GEM) throughout the region. In the ground-level air, GEM ranged from 8 to 454 ng m-3, exceeding the Northern Hemispheric average (~1.4 ng m-3) by up to two orders of magnitude. Much higher concentrations, up to 44,700 ng m-3, were found in the interstitial air of reprocessed mineral wastes, sediment, and soil. These highly elevated present-day GEM values are due, at least in part, to the disproportionation of legacy calomel, as supported by the presence of HgI in the reprocessed wastes and by the GEM release pattern from calomel disproportionation. Our results imply that the contribution of historical Ag refining to atmospheric Hg emissions must be re-evaluated to account for calomel and its subsequent disproportionation and releases of GEM to the present-day.