Hydrochemical characteristics of rural community groundwater supply in Blantyre, southern Malawi

The Zumbi dos Palmares land reform settlement lacks modern facilities for water and sewage treatment. Local farmers often use shallow wells as alternative source of water supply, because the water table is reasonably high in the region. This work presents a multivariate analysis assessment of physicochemical and bacteriological parameters and pesticide residues in water samples collected from these shallow wells. The physicochemical parameters analyzed were: conductivity, pH, DOC (dissolved organic carbon), nitrate, turbidity, and bacteriological analysis measuring total and fecal coliforms. The results show non-compliance with Brazilian legal standards in most samples where low pH values were found, characterizing the presence of acidic waters. Another example of non-compliance is the presence of total and fecal coliforms in for drinking water in most of the samples and, in some cases, very high values (2,400 CFU). Some wells showed high conductivity values, probably associated with a history of oceanic intrusion. Analyses determining the contamination by pesticides show the presence of ametrine, atrazine, methyl parathion, carbaryl and hexazinone. The concentration for these compounds ranged from 0.14 to 1.17 μg/L. Ordinance No 2914/2011 from the Brazilian Ministry of Health establishes the acceptable limits for atrazine and methyl parathion as 9 μg L −1 and 2 μg L −1 . None of these exceeded the allowable Brazilian and European limits. However, for the other two pesticides, the European Legislation (Council Directive) recommends the maximum allowable concentration of 0.1 μg L −1 and, 0.5 μg L −1 for total pesticides. Our samples that were above the quantifiable limit of 50 ng L −1 , were also above the European limit values. Our results therefore suggest that water gathered from shallow wells at the Zumbi dos Palmares settlement is not proper for consumption without proper disinfection treatments.

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“…2). Similar results were found in shallow wells in Africa [20, 21]. High water conductivity may be also related to soil characteristics.…”

Section: Resultssupporting

confidence: 79%

An integrated assessment of water quality in a land reform settlement in northern Rio de Janeiro state, Brazil

Portal

Pedlowski

Almeida

et al. 2019

Heliyon

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“…The assessment of geochemical properties was estimated by concentration (meq/l) levels of anions (HCO 3 − , SO 4 2− and Cl − ) and cations (Ca 2+ , Mg 2+ , Na +, and K + ) in collected groundwater samples. Several researchers have conducted similar types (Yang et al, 2016;Mapoma et al, 2016;Krishna et al, 2015;Suma et al, 2015). In Fig.…”

Section: Hydro-geochemical Analysismentioning

confidence: 99%

Geochemical and statistical evaluation of groundwater in the Thamirabarani river basin, south India

Chellaiah¹,

Basker²,

Pravin³

et al. 2021

Preprint

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In the present study, an attempt has been made to develop the dictate metrics using a multi-proxy approach, i.e., spatial-temporal analysis, statistical evaluation, and hydrogeochemical analysis for 45 water samples located in the Thamirabarani river basin in Tamil Nadu, India. In order to evaluate the aptness of developed metrics for agriculture and domestic needs, eleven years dataset was analyzed and compared with national and international standards. Monitoring and analysis results revealed that the concentration of calcium and chloride ion was on the higher side in all the selected locations. These higher values may be attributed to the regional point sources such as untreated water disposal and off-peak sources such as agriculture practices. The principal component analysis resulted in 84.2% of the total variance in the post-monsoon season dataset. The major analyzed cations and anions were observed in the following order: Na+> Ca2+> Mg2+> K+ and Cl−> HCO3−> SO42−> NO3−, respectively. Overall, this study revealed that the studied area's groundwater quality was significantly affected by the high salinity in the region, probably due to anthropogenic activities and unprotected river sites.

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“…Nitrate is relatively stable in aerobic conditions; point sources, such as pit latrines, pose a long-term risk 7,29,30 . High nitrate concentrations in groundwater have been recorded in some regions of Malawi 10,[32][33][34] . Prevention of nitrate in groundwater is critical to maintain water quality as nitrate levels do not naturally decrease, even when sources of contamination are removed 29,31 .…”

Section: Introductionmentioning

confidence: 99%

Spatial model of groundwater contamination risks from pit-latrines to 2070: Case Study Malawi

Hinton,

Kalin,

Kanjaye

et al. 2023

Preprint

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Pit-latrines are central to achieving SDG6, “clean water and sanitation for all”. Unless safely managed, pit-latrines result in groundwater contamination, which increases morbidity and mortality. Despite this, there have been no long-term spatial projections of future pit-latrine contamination risks. National survey data of over 100,000 water-points and 260,000 pit-latrines in Malawi was used to generate a novel, high-resolution model of pit-latrines from 2020–2070 under 5 population, and 3 sanitation policy, scenarios. The ‘business as usual’ model predicts a three-fold increase in the number of water-points at risk of microbial pit-latrine contamination between 2020–2070, with a seven-fold increase in the highest contamination risks. Current nitrogen loading into pit-latrines is comparable to national fertiliser application. The model predicts 8.2 mega-tonnes of faecal nitrogen will be disposed of into subsequently abandoned pit-latrines between 2020–2070. Guided intervention is necessary to prevent SDG6’s push for sanitation undermining its goal of clean water.

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Hydrochemical characteristics of rural community groundwater supply in Blantyre, southern Malawi

Cited by 17 publications

References 22 publications

An integrated assessment of water quality in a land reform settlement in northern Rio de Janeiro state, Brazil

An integrated assessment of water quality in a land reform settlement in northern Rio de Janeiro state, Brazil

Geochemical and statistical evaluation of groundwater in the Thamirabarani river basin, south India

Spatial model of groundwater contamination risks from pit-latrines to 2070: Case Study Malawi

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