In order to investigate the mechanism of arsenic release to anoxic ground water in alluvial aquifers, we sampled ground waters from three piezometer nests, 79 shallow (< 45m) wells, and 6 deep (> 80m) wells, in an area 750 m by 450 m, just north of Barasat, near Kolkata (Calcutta), in southern West Bengal. High concentrations of arsenic (200 -1180 µg l -1 ) are accompanied by high concentrations of iron (3 -13.7 mg l -1 ) and phosphate (1 -6.5 mg l -1 ). Ground water that is rich in manganese (1 -5.3 mg l -1 ) contains < 50 µg l -1 of arsenic. The composition of shallow ground water varies at the 100m-scale laterally and the metre-scale vertically, with vertical gradients in arsenic concentration reaching 200 µg l -1 m -1 . The arsenic is supplied by reductive dissolution of FeOOH and release of the sorbed arsenic to solution. The process is driven by natural organic matter in peaty strata both within the aquifer sands and in the overlying confining unit. In well waters, thermo-tolerant coliforms, a proxy for faecal contamination, are not present in high numbers (< 10 cfu/100 ml in 85% of wells) showing that faecally-derived organic matter does not enter the aquifer, does not drive reduction of FeOOH, and so does not release arsenic to ground water.Arsenic concentrations are high (>> 50 µg l -1 ) where reduction of FeOOH oxide is complete and its entire load of sorbed arsenic is released to solution, at which point the aquifer sediments become grey in colour as FeOOH vanishes. Where reduction incomplete, the sediments are brown in colour and resorption of arsenic to residual FeOOH keeps arsenic concentrations below 10 µg l -1 in the presence of dissolved iron. Sorbed arsenic released by reduction of manganese oxides does not release arsenic to ground water because the arsenic resorbs to FeOOH. Arsenic pollution of ground water is common in the alluvial aquifers of the Bengal Basin because Himalayan erosion supplies immature sediments, with low surface-loadings of FeOOH on mineral grains, to a depositional environment that is rich in organic mater so that complete reduction of FeOOH is common.

BackgroundStunting in early life has considerable human and economic costs. The purpose of the study was to identify factors associated with stunting among children aged 0-23 months in Indonesia to inform the design of appropriate policy and programme responses.MethodsDeterminants of child stunting, including severe stunting, were examined in three districts in Indonesia using data from a cross-sectional survey conducted in 2011. A total of 1366 children were included. The analysis used multiple logistic regression to determine unadjusted and adjusted odds ratios.ResultsThe prevalence of stunting and severe stunting was 28.4 % and 6.7 %, respectively. The multivariate analysis on determinants of stunting identified a significant interaction between household sanitary facility and household water treatment (P for interaction = 0.007) after controlling for potential covariates: in households that drank untreated water, the adjusted odds on child stunting was over three times higher if the household used a unimproved latrine (adjusted odds ratio 3.47, 95 % confidence interval 1.73-7.28, P <0.001); however, in households that drank treated water, the adjusted odds on child stunting was not significantly higher if the household used an unimproved latrine (adjusted odds ratio 1.27, 95 % confidence interval 0.99-1.63, P = 0.06). Other significant risk factors included male sex, older child age and lower wealth quintile. The risk factors for severe stunting included male sex, older child age, lower wealth quintile, no antenatal care in a health facility, and mother’s participation in decisions on what food was cooked in the household.ConclusionsThe combination of unimproved latrines and untreated drinking water was associated with an increased odds on stunting in Indonesia compared with improved conditions. Policies and programmes to address child stunting in Indonesia must consider water, sanitation and hygiene interventions. Operational research is needed to determine how best to converge and integrate water, sanitation and hygiene interventions into a broader multisectoral approach to reduce stunting in Indonesia.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-3339-8) contains supplementary material, which is available to authorized users.

ObjectivesIncreasing evidence suggests that water, sanitation and hygiene (WASH) practices affect linear growth in early childhood. We determined the association between household access to water, sanitation and personal hygiene practices with stunting among children aged 0–23 months in rural India.SettingIndia.ParticipantsA total of 10 364, 34 639 and 1282 under-2s who participated in the 2005–2006 National Family Health Survey (NFHS-3), the 2011 Hunger and Malnutrition Survey (HUNGaMA) and the 2012 Comprehensive Nutrition Survey in Maharashtra (CNSM), respectively, were included in the analysis.Primary outcome measuresThe association between WASH indicators and child stunting was assessed using logistic regression models.ResultsThe prevalence of stunting ranged from 25% to 50% across the three studies. Compared with open defecation, household access to toilet facility was associated with a 16–39% reduced odds of stunting among children aged 0–23 months, after adjusting for all potential confounders (NHFS-3 (OR=0.84, 95% CI 0.71 to 0.99); HUNGaMA (OR=0.84, 95% CI 0.78 to 0.91); CNSM (OR=0.61, 95% CI 0.44 to 0.85)). Household access to improved water supply or piped water was not in itself associated with stunting. The caregiver's self-reported practices of washing hands with soap before meals (OR=0.85, 95% CI 0.76 to 0.94) or after defecation (OR=0.86, 95% CI 0.80 to 0.93) were inversely associated with child stunting. However, the inverse association between reported personal hygiene practices and stunting was stronger among households with access to toilet facility or piped water (all interaction terms, p<0.05).ConclusionsImproved conditions of sanitation and hygiene practices are associated with reduced prevalence of stunting in rural India. Policies and programming aiming to address child stunting should encompass WASH interventions, thus shifting the emphasis from nutrition-specific to nutrition-sensitive programming. Future randomised trials are warranted to validate the causal association.

Objective To assess the prevalence of menstrual hygiene management (MHM) knowledge and practices among adolescent schoolgirls in Indonesia, and assess factors associated with poor MHM and school absenteeism due to menstruation. Methods A cross‐sectional survey enrolled a representative sample of urban and rural school‐going girls aged 12–19 years in four provinces of Indonesia. A semi‐structured, self‐administered questionnaire obtained socio‐demographic characteristics, knowledge, practices and attitudes related to menstruation, MHM and school absenteeism. School water, sanitation and hygiene (WASH) facilities were also assessed. Univariate weighted population prevalence was estimated and multivariable logit regression analyses applied to explore associations. Results A total of 1159 adolescent girls with a mean age of 15 years (SD = 1.8) participated. Most girls (90.8%, 95% confidence interval (95% CI) = 79.7–96.1) had reached menarche. Over half (64.1%, 95% CI = 49.9–76.2) reported poor MHM practices, and 11.1% (95% CI = 8.1–15.2) had missed one or more days of school during their most recent menstrual period. Poor MHM practices were associated with rural residence (Adjusted odds ratio (AOR) = 1.73, 95% CI = 1.13–2.64), province (various AOR), lower school grade (AOR = 1.69, 95% CI = 1.05–2.74) and low knowledge of menstruation (AOR = 3.49, 95% CI = 1.61–7.58). Absenteeism was associated with living in rural areas (AOR = 3.96, 95% CI = 3.02–5.18), province (various AOR), higher school grade (AOR = 3.02, 95% CI = 2.08–4.38), believing menstruation should be kept secret (AOR = 1.47, 95% CI = 1.03–2.11), experiencing serious menstrual pain (AOR = 1.68, 95% CI = 1.06–2.68) and showed mixed associations with school WASH facilities. Conclusions High prevalence of poor MHM and considerable school absenteeism due to menstruation among Indonesian girls highlight the need for improved interventions that reach girls at a young age and address knowledge, shame and secrecy, acceptability of WASH infrastructure and menstrual pain management.

Current strategies to protect groundwater sources from microbial contamination (e.g., wellhead protection areas) rely upon natural attenuation of microorganisms between wells or springs and potential sources of contamination and are determined using average (macroscopic) groundwater flow velocities defined by Darcy's Law. However, field studies of sewage contamination and microbial transport using deliberately applied tracers provide evidence of groundwater flow paths that permit the transport of microorganisms by rapid, statistically extreme velocities. These paths can be detected because of (i) the high concentrations of bacteria and viruses that enter near-surface environments in sewage or are deliberately applied as tracers (e.g., bacteriophage); and (ii) low detection limits of these microorganisms in water. Such paths must comprise linked microscopic pathways (sub-paths) that are biased toward high groundwater velocities. In media where microorganisms may be excluded from the matrix (pores and fissures), the disparity between the average linear velocity of groundwater flow and flow velocities transporting released or applied microorganisms is intensified. It is critical to recognise the limited protection afforded by source protection measures that disregard rapid, statistically extreme groundwater velocities transporting pathogenic microorganisms, particularly in areas dependent upon untreated groundwater supplies.