Pit latrines and their impacts on groundwater quality: a systematic review.

BackgroundPit latrines are one of the most common human excreta disposal systems in low-income countries, and their use is on the rise as countries aim to meet the sanitation-related target of the Millennium Development Goals. There is concern, however, that discharges of chemical and microbial contaminants from pit latrines to groundwater may negatively affect human health.ObjectivesOur goals were to a) calculate global pit latrine coverage, b) systematically review empirical studies of the impacts of pit latrines on groundwater quality, c) evaluate latrine siting standards, and d) identify knowledge gaps regarding the potential for and consequences of groundwater contamination by latrines.MethodsWe used existing survey and population data to calculate global pit latrine coverage. We reviewed the scientific literature on the occurrence of contaminants originating from pit latrines and considered the factors affecting transport of these contaminants. Data were extracted from peer-reviewed articles, books, and reports identified using Web of ScienceSM, PubMed, Google, and document reference lists.DiscussionWe estimated that approximately 1.77 billion people use pit latrines as their primary means of sanitation. Studies of pit latrines and groundwater are limited and have generally focused on only a few indicator contaminants. Although groundwater contamination is frequently observed downstream of latrines, contaminant transport distances, recommendations based on empirical studies, and siting guidelines are variable and not well aligned with one another.ConclusionsIn order to improve environmental and human health, future research should examine a larger set of contextual variables, improve measurement approaches, and develop better criteria for siting pit latrines

Incidence of hypertension in people with HIV who are treated with integrase inhibitors versus other antiretroviral regimens in the RESPOND cohort consortium.

OBJECTIVE To compare the incidence of hypertension in people living with HIV receiving integrase strand transfer inhibitor (INSTI)-based antiretroviral therapy (ART) versus non-nucleoside reverse transcriptase inhibitors (NNRTIs) or boosted protease inhibitors (PIs) in the RESPOND consortium of HIV cohorts. METHODS Eligible people with HIV were aged ≥18 years who initiated a new three-drug ART regimen for the first time (baseline), did not have hypertension, and had at least two follow-up blood pressure (BP) measurements. Hypertension was defined as two consecutive systolic BP measurements ≥140 mmHg and/or diastolic BP ≥90 mmHg or initiation of antihypertensives. Multivariable Poisson regression was used to determine adjusted incidence rate ratios (aIRRs) of hypertension, overall and in those who were ART naïve or experienced at baseline. RESULTS Overall, 4606 people living with HIV were eligible (INSTIs 3164, NNRTIs 807, PIs 635). The median baseline systolic BP, diastolic BP, and age were 120 (interquartile range [IQR] 113-130) mmHg, 78 (70-82) mmHg, and 43 (34-50) years, respectively. Over 8380.4 person-years (median follow-up 1.5 [IQR 1.0-2.7] years), 1058 (23.0%) participants developed hypertension (incidence rate 126.2/1000 person-years, 95% confidence interval [CI] 118.9-134.1). Participants receiving INSTIs had a higher incidence of hypertension than those receiving NNRTIs (aIRR 1.76; 95% CI 1.47-2.11), whereas the incidence was no different in those receiving PIs (aIRR 1.07; 95% CI 0.89-1.29). The results were similar when the analysis was stratified by ART status at baseline. CONCLUSION Although unmeasured confounding and channelling bias cannot be excluded, INSTIs were associated with a higher incidence of hypertension than were NNRTIs, but rates were similar to those of PIs overall, in ART-naïve and ART-experienced participants within RESPOND

Soil Change: Impacts and Responses

Peer reviewe

Hyperimmune immunoglobulin for hospitalised patients with COVID-19 (ITAC): a double-blind, placebo-controlled, phase 3, randomised trial

BACKGROUND: Passive immunotherapy using hyperimmune intravenous immunoglobulin (hIVIG) to SARS-CoV-2, derived from recovered donors, is a potential rapidly available, specific therapy for an outbreak infection such as SARS-CoV-2. Findings from randomised clinical trials of hIVIG for the treatment of COVID-19 are limited. METHODS: In this international randomised, double-blind, placebo-controlled trial, hospitalised patients with COVID-19 who had been symptomatic for up to 12 days and did not have acute end-organ failure were randomly assigned (1:1) to receive either hIVIG or an equivalent volume of saline as placebo, in addition to remdesivir, when not contraindicated, and other standard clinical care. Randomisation was stratified by site pharmacy; schedules were prepared using a mass-weighted urn design. Infusions were prepared and masked by trial pharmacists; all other investigators, research staff, and trial participants were masked to group allocation. Follow-up was for 28 days. The primary outcome was measured at day 7 by a seven-category ordinal endpoint that considered pulmonary status and extrapulmonary complications and ranged from no limiting symptoms to death. Deaths and adverse events, including organ failure and serious infections, were used to define composite safety outcomes at days 7 and 28. Prespecified subgroup analyses were carried out for efficacy and safety outcomes by duration of symptoms, the presence of anti-spike neutralising antibodies, and other baseline factors. Analyses were done on a modified intention-to-treat (mITT) population, which included all randomly assigned participants who met eligibility criteria and received all or part of the assigned study product infusion. This study is registered with ClinicalTrials.gov, NCT04546581. FINDINGS: From Oct 8, 2020, to Feb 10, 2021, 593 participants (n=301 hIVIG, n=292 placebo) were enrolled at 63 sites in 11 countries; 579 patients were included in the mITT analysis. Compared with placebo, the hIVIG group did not have significantly greater odds of a more favourable outcome at day 7; the adjusted OR was 1·06 (95% CI 0·77–1·45; p=0·72). Infusions were well tolerated, although infusion reactions were more common in the hIVIG group (18·6% vs 9·5% for placebo; p=0·002). The percentage with the composite safety outcome at day 7 was similar for the hIVIG (24%) and placebo groups (25%; OR 0·98, 95% CI 0·66–1·46; p=0·91). The ORs for the day 7 ordinal outcome did not vary for subgroups considered, but there was evidence of heterogeneity of the treatment effect for the day 7 composite safety outcome: risk was greater for hIVIG compared with placebo for patients who were antibody positive (OR 2·21, 95% CI 1·14–4·29); for patients who were antibody negative, the OR was 0·51 (0·29–0·90; pinteraction=0·001). INTERPRETATION: When administered with standard of care including remdesivir, SARS-CoV-2 hIVIG did not demonstrate efficacy among patients hospitalised with COVID-19 without end-organ failure. The safety of hIVIG might vary by the presence of endogenous neutralising antibodies at entry. FUNDING: US National Institutes of Health

Understanding Sources of Zinc Contamination in Waterways of Eugene-Springfield, OR

1 page.Data from Amazon Creek, Willow Creek, Spring Creek and the Willamette River through Eugene, Oregon indicate that concentrations of zinc in stormwater runoff and in receiving streams have been increasing over the past 20 years. As such, the causes and extent of elevated zinc levels within the Eugene-Springfield Metro Area are the focus of this study. Preliminary research identified zinc-based moss control products, tire and brake wear, industrial discharges, and more, as likely sources of zinc to the environment. Further efforts, including spatial and temporal analysis through the construction of a series of maps is ongoing. Results aim to make clearer primary sources of zinc contamination within the study area, add to our understanding of the extent of zinc contamination within the area, and inform regulatory guidance for minimizing zinc loading to the environment

Pit latrines and their impacts on groundwater quality: a systematic review.

BackgroundPit latrines are one of the most common human excreta disposal systems in low-income countries, and their use is on the rise as countries aim to meet the sanitation-related target of the Millennium Development Goals. There is concern, however, that discharges of chemical and microbial contaminants from pit latrines to groundwater may negatively affect human health.ObjectivesOur goals were to a) calculate global pit latrine coverage, b) systematically review empirical studies of the impacts of pit latrines on groundwater quality, c) evaluate latrine siting standards, and d) identify knowledge gaps regarding the potential for and consequences of groundwater contamination by latrines.MethodsWe used existing survey and population data to calculate global pit latrine coverage. We reviewed the scientific literature on the occurrence of contaminants originating from pit latrines and considered the factors affecting transport of these contaminants. Data were extracted from peer-reviewed articles, books, and reports identified using Web of ScienceSM, PubMed, Google, and document reference lists.DiscussionWe estimated that approximately 1.77 billion people use pit latrines as their primary means of sanitation. Studies of pit latrines and groundwater are limited and have generally focused on only a few indicator contaminants. Although groundwater contamination is frequently observed downstream of latrines, contaminant transport distances, recommendations based on empirical studies, and siting guidelines are variable and not well aligned with one another.ConclusionsIn order to improve environmental and human health, future research should examine a larger set of contextual variables, improve measurement approaches, and develop better criteria for siting pit latrines

Near-Surface Wetland Sediments as a Source of Arsenic Release to Ground Water in Asia

Tens of millions of people in south and southeast Asia routinely consume ground water that has unsafe arsenic levels1, 2. Arsenic is naturally derived from eroded Himalayan sediments, and is believed to enter solution following reductive release from solid phases under anaerobic conditions. However, the processes governing aqueous concentrations and locations of arsenic release to pore water remain unresolved, limiting our ability to predict arsenic concentrations spatially (between wells) and temporally (future concentrations) and to assess the impact of human activities on the arsenic problem3, 4, 5, 6, 7, 8, 9. This uncertainty is partly attributed to a poor understanding of groundwater flow paths altered by extensive irrigation pumping in the Ganges-Brahmaputra delta10, where most research has focused. Here, using hydrologic and (bio)geochemical measurements, we show that on the minimally disturbed Mekong delta of Cambodia, arsenic is released from near-surface, river-derived sediments and transported, on a centennial timescale, through the underlying aquifer back to the river. Owing to similarities in geologic deposition, aquifer source rock and regional hydrologic gradients11, 12, 13, 14, 15, our results represent a model for understanding pre-disturbance conditions for other major deltas in Asia. Furthermore, the observation of strong hydrologic influence on arsenic behaviour indicates that release and transport of arsenic are sensitive to continuing and impending anthropogenic disturbances. In particular, groundwater pumping for irrigation, changes in agricultural practices, sediment excavation, levee construction and upstream dam installations will alter the hydraulic regime and/or arsenic source material and, by extension, influence groundwater arsenic concentrations and the future of this health problem

Spatial statistical modeling of arsenic accumulation in microsites of diverse soils

Determining reaction mechanisms that control the mobility of nutrients and toxic elements in soil matrices is confounded by complex assemblages of minerals, non-crystalline solids, organic matter, and biota. Our objective was to infer the chemical elements and solids that contribute to As binding in matrices of soil samples from different pedogenic environments at the micrometer spatial scale. Arsenic was reacted with and imaged in thin weathering coatings on eight quartz sand grains separated from soils of different drainage classes to vary contents of Fe and Al (hydr)oxides, organic carbon (OC), and other elements. The grains were analyzed using X-ray fluorescence microprobe (µ-XRF) imaging and microscale X-ray absorption near edge structure (μ-XANES) spectroscopy before and after treatment with 0.1 mM As(V) solution. Partial correlation analyses and regression models developed from multi-element µ-XRF signals collected across 100 × 100 µm2 areas of sand-grain coatings inferred augmenting effects of Fe, Zn, Ti, Mn, or Cu on As retention. Significant partial correlations (r′ > 0.11) between Fe and Al from time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis of most samples suggested that Fe and Al (hydr)oxides were partially co-localized at the microscale. Linear combination fitting (LCF) results for As K-edge μ-XANES spectra collected across grain coatings typically included >80% of As(V) adsorbed on goethite, along with varying proportions of standards of As(V) adsorbed on boehmite, As(V) or As(III) bound to Fe(III)-treated peat, and dimethylarsinic acid. Complementary fits for Fe K-edge μ-XANES spectra included ≥50% of the Fe(III)-treated peat standard for all samples, along with goethite. Our collective results inferred a dominance of Fe and possibly Al (hydr)oxides in controlling As immobilization, with variable contributions from Zn, Ti, Cu, or Mn, both across the coating of a single sand grain and between grains from soils developed under different pedogenic environments. Overall, these results highlight the extreme heterogeneity of soils on the microscale and have implications on soil management for mitigating the adverse environmental impacts of As