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1.
Water Res ; 206: 117734, 2021 Nov 01.
Article in English | MEDLINE | ID: mdl-34655933

ABSTRACT

Faecal indicator organisms (FIOs) are limited in their ability to protect public health from the microbial contamination of drinking water because of their transience and time required to deliver a result. We evaluated alternative rapid, and potentially more resilient, approaches against a benchmark FIO of thermotolerant coliforms (TTCs) to characterise faecal contamination over 14 months at 40 groundwater sources in a Ugandan town. Rapid approaches included: in-situ tryptophan-like fluorescence (TLF), humic-like fluorescence (HLF), turbidity; sanitary inspections; and total bacterial cells by flow cytometry. TTCs varied widely in six sampling visits: a third of sources tested both positive and negative, 50% of sources had a range of at least 720 cfu/100 mL, and a two-day heavy rainfall event increased median TTCs five-fold. Using source medians, TLF was the best predictor in logistic regression models of TTCs ≥10 cfu/100 mL (AUC 0.88) and best correlated to TTC enumeration (ρs 0.81), with HLF performing similarly. Relationships between TLF or HLF and TTCs were stronger in the wet season than the dry season, when TLF and HLF were instead more associated with total bacterial cells. Source rank-order between sampling rounds was considerably more consistent, according to cross-correlations, using TLF or HLF (min ρs 0.81) than TTCs (min ρs 0.34). Furthermore, dry season TLF and HLF cross-correlated more strongly (ρs 0.68) than dry season TTCs (ρs 0.50) with wet season TTCs, when TTCs were elevated. In-situ TLF or HLF are more rapid and resilient indicators of faecal contamination risk than TTCs.


Subject(s)
Drinking Water , Groundwater , Environmental Monitoring , Feces , Spectrometry, Fluorescence , Water Microbiology
3.
Sci Rep ; 10(1): 15379, 2020 09 21.
Article in English | MEDLINE | ID: mdl-32958794

ABSTRACT

Fluorescent natural organic matter at tryptophan-like (TLF) and humic-like fluorescence (HLF) peaks is associated with the presence and enumeration of faecal indicator bacteria in groundwater. We hypothesise, however, that it is predominantly extracellular material that fluoresces at these wavelengths, not bacterial cells. We quantified total (unfiltered) and extracellular (filtered at < 0.22 µm) TLF and HLF in 140 groundwater sources across a range of urban population densities in Kenya, Malawi, Senegal, and Uganda. Where changes in fluorescence occurred following filtration they were correlated with potential controlling variables. A significant reduction in TLF following filtration (ΔTLF) was observed across the entire dataset, although the majority of the signal remained and thus considered extracellular (median 96.9%). ΔTLF was only significant in more urbanised study areas where TLF was greatest. Beneath Dakar, Senegal, ΔTLF was significantly correlated to total bacterial cells (ρs 0.51). No significant change in HLF following filtration across all data indicates these fluorophores are extracellular. Our results suggest that TLF and HLF are more mobile than faecal indicator bacteria and larger pathogens in groundwater, as the predominantly extracellular fluorophores are less prone to straining. Consequently, TLF/HLF are more precautionary indicators of microbial risks than faecal indicator bacteria in groundwater-derived drinking water.


Subject(s)
Feces/microbiology , Fluorescent Dyes/chemistry , Groundwater/microbiology , Tryptophan/chemistry , Africa , Drinking Water/chemistry , Drinking Water/microbiology , Environmental Monitoring/methods , Fluorescence , Groundwater/chemistry , Water Microbiology , Water Supply/methods
4.
Nature ; 572(7768): 230-234, 2019 08.
Article in English | MEDLINE | ID: mdl-31391559

ABSTRACT

Groundwater in sub-Saharan Africa supports livelihoods and poverty alleviation1,2, maintains vital ecosystems, and strongly influences terrestrial water and energy budgets3. Yet the hydrological processes that govern groundwater recharge and sustainability-and their sensitivity to climatic variability-are poorly constrained4,5. Given the absence of firm observational constraints, it remains to be seen whether model-based projections of decreased water resources in dry parts of the region4 are justified. Here we show, through analysis of multidecadal groundwater hydrographs across sub-Saharan Africa, that levels of aridity dictate the predominant recharge processes, whereas local hydrogeology influences the type and sensitivity of precipitation-recharge relationships. Recharge in some humid locations varies by as little as five per cent (by coefficient of variation) across a wide range of annual precipitation values. Other regions, by contrast, show roughly linear precipitation-recharge relationships, with precipitation thresholds (of roughly ten millimetres or less per day) governing the initiation of recharge. These thresholds tend to rise as aridity increases, and recharge in drylands is more episodic and increasingly dominated by focused recharge through losses from ephemeral overland flows. Extreme annual recharge is commonly associated with intense rainfall and flooding events, themselves often driven by large-scale climate controls. Intense precipitation, even during years of lower overall precipitation, produces some of the largest years of recharge in some dry subtropical locations. Our results therefore challenge the 'high certainty' consensus regarding decreasing water resources4 in such regions of sub-Saharan Africa. The potential resilience of groundwater to climate variability in many areas that is revealed by these precipitation-recharge relationships is essential for informing reliable predictions of climate-change impacts and adaptation strategies.


Subject(s)
Groundwater/analysis , Rain , Africa South of the Sahara , Desert Climate , Droughts/statistics & numerical data
5.
Int J Environ Health Res ; 29(4): 457-478, 2019 Aug.
Article in English | MEDLINE | ID: mdl-30545246

ABSTRACT

Tackling global inequalities in access to Water, Sanitation and Hygiene (WASH) remains an urgent issue - 58% of annual diarrhoeal deaths are caused by inadequate WASH provision. A global context of increasing urbanisation, changing demographics and health transitions demands an understanding and impact of WASH on a broad set of health outcomes. We examine the literature, in terms of health outcomes, considering WASH access and interventions in urban sub-Saharan Africa from 2000 to 2017. Our review of studies which evaluate the effectiveness of specific WASH interventions, reveals an emphasis of WASH research on acute communicable diseases, particularly diarrhoeal diseases. In contrast, chronic communicable and non-communicable health outcomes were notable gaps in the literature as well as a lack of focus on cross-cutting issues, such as ageing, well-being and gender equality. We recommend a broader focus of WASH research and interventions in urban Africa to better reflect the demographic and health transitions happening. Abbreviations: CBA: Controlled Before and After; GSD: Government Service Delivery; IWDSSD: International Drinking-Water, Supply and Sanitation Decade (IDWSSD); KAP: Knowledge, Attitudes and Practices; IBD: Irritable Bowel Diseases; MDG: Millennium Development Goals; NTD: Neglected Tropical Diseases; PSSD: Private Sector Service Delivery; SDG: Sustainable Development Goals; SSA: Sub Saharan Africa; SODIS: Solar Disinfection System; STH: Soil Transmitted Helminths; RCT: Randomised Control Trial; WASH: Water Sanitation and Hygiene; WHO: World Health Organization.


Subject(s)
Hygiene/standards , Sanitation/standards , Urban Health , Water Supply/standards , Africa South of the Sahara , Communicable Disease Control , Health Behavior , Humans , Noncommunicable Diseases/prevention & control , Urban Health/trends
6.
BMC Pregnancy Childbirth ; 16: 83, 2016 Apr 21.
Article in English | MEDLINE | ID: mdl-27101821

ABSTRACT

BACKGROUND: Beneficial newborn care practices can improve newborn survival. However, little is known about the factors that affect adoption of these practices. METHODS: Cross-sectional study conducted among 1,616 mothers who had delivered in the past year in two health sub-districts (Luuka and Buyende) in Eastern Uganda. Data collection took place between November and December 2011. Data were collected on socio-demographic and economic characteristics, antenatal care visits, skilled delivery attendance, parity, distance to health facility and early newborn care knowledge and practices. Descriptive statistics were computed to determine the proportion of mothers who adopted beneficial newborn care practices (optimal thermal care; good feeding practices; weighing and immunizing the baby immediately after birth; and good cord care) during the neonatal period. We conducted multivariable logistic regression to assess the covariates of adoption of all beneficial newborn care practices. Analysis was done using STATA statistical software, version 12.1. RESULTS: Of the 1,616 mothers enrolled, 622 (38.5%) were aged 25-34; 1,472 (91.1%) were married; 1,096 (67.8%) had primary education; while 1,357 (84%) were laborers or peasants. Utilization of all beneficial newborn care practices was 11.7%; lower in Luuka (9.4%, n = 797) than in Buyende health sub-district (13.9%, n = 819; p = 0.005). Good cord care (83.6% in Luuka; 95% in Buyende) and immunization of newborn (80.7% in Luuka; 82.5% in Buyende) were the most prevalent newborn care practices reported by mothers. At the multivariable analysis, number of ANC visits (3-4 vs. 1-2: Adjusted (Adj.) Odds Ratio (OR) = 1.69, 95% CI = 1.13, 2.52), skilled delivery (Adj. OR = 2.66, 95% CI = 1.92, 3.69), socio-economic status (middle vs. low: Adj. OR = 1.57, 95% CI = 1.09, 2.26) were positively associated with adoption of all beneficial newborn care practices among mothers. CONCLUSION: Adoption of all beneficial newborn care practices was low, although associated with higher ANC visits; middle-level socio-economic status and skilled delivery attendance. These findings suggest a need for interventions to improve quality ANC and skilled delivery attendance as well as targeting of women with low and high socio-economic status with newborn care health educational messages, improved work conditions for breastfeeding, and supportive policies at national level for uptake of newborn care practices.


Subject(s)
Health Knowledge, Attitudes, Practice , Infant Care/psychology , Mothers/psychology , Rural Population , Adult , Cross-Sectional Studies , Delivery, Obstetric/methods , Delivery, Obstetric/psychology , Female , Humans , Infant Care/methods , Infant, Newborn , Odds Ratio , Pregnancy , Prenatal Care/psychology , Prenatal Care/statistics & numerical data , Socioeconomic Factors , Uganda
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