Risk assessment to groundwater of pit latrine rural sanitation policy in developing country settings

Jan O. Back, Michael O. Rivett, Laura B. Hinz, Nyree Mackay, Gift J. Wanangwa, Owen L. Phiri, Chrispine Emmanuel Songola, Mavuto A.S. Thomas, Steve Kumwenda, Muthi Nhlema, Alexandra V.M. Miller, Robert M. Kalin

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Parallel global rise in pit-latrine sanitation and groundwater-supply provision is of concern due to the frequent spatial proximity of these activities. Study of such an area in Malawi has allowed understanding of risks posed to groundwater from the recent implementation of a typical developing-country pit-latrine sanitation policy to be gained. This has assisted the development of a risk-assessment framework approach pragmatic to regulatory-practitioner management of this issue. The framework involves water-supply and pit-latrine mapping, monitoring of key groundwater contamination indicators and surveys of possible environmental site-condition factors and culminates in an integrated statistical evaluation of these datasets to identify the significant factors controlling risks posed. Our approach usefully establishes groundwater-quality baseline conditions of a potentially emergent issue for the study area. Such baselines are foundational to future trend discernment and contaminant natural attenuation verification critical to policies globally. Attribution of borehole contamination to pit-latrine loading should involve, as illustrated, the use of the range of contamination (chemical, microbiological) tracers available recognising none are ideal and several radial and capture-zone metrics that together may provide a weight of evidence. Elevated, albeit low-concentration, nitrate correlated with some radial metrics and was tentatively suggestive of emerging latrine influences. Longer term monitoring is, however, necessary to verify that the commonly observed latrine-borehole separation distances (29–58 m), alongside statutory guidelines, do not constitute significant risk. Borehole contamination was limited and correlation with various environmental-site condition factors also limited. This was potentially ascribed to effectiveness of attenuation to date, monitoring of an emergent problem yet to manifest, or else contamination from other sources. High borehole usage and protective wall absence correlated with observed microbiological contamination incidence, but could relate to increased human/animal activity close to these poorly protected boreholes. Additional to factors assessed, a groundwater-vulnerability factor is recommended that critically relies upon improved proactive securing of underpinning data during borehole/latrine installations. On-going concerns are wide ranging, including poorly constrained pit-latrine input, difficulties in assessing in-situ plume natural attenuation and possible disposal of used motor oils to latrines.

LanguageEnglish
Pages592-610
Number of pages19
JournalScience of the Total Environment
Volume613-614
Early online date26 Sep 2017
DOIs
Publication statusPublished - 1 Feb 2018

Fingerprint

Sanitation
Boreholes
sanitation
Developing countries
Risk assessment
Groundwater
risk assessment
borehole
developing world
Contamination
groundwater
Natural attenuation
natural attenuation
condition factor
Monitoring
monitoring
Chemical contamination
baseline conditions
Water supply
Nitrates

Keywords

  • pit latrine
  • Malawi
  • risk
  • groundwater quality
  • sanitation
  • Millennium development goals

Cite this

Back, Jan O. ; Rivett, Michael O. ; Hinz, Laura B. ; Mackay, Nyree ; Wanangwa, Gift J. ; Phiri, Owen L. ; Songola, Chrispine Emmanuel ; Thomas, Mavuto A.S. ; Kumwenda, Steve ; Nhlema, Muthi ; Miller, Alexandra V.M. ; Kalin, Robert M. / Risk assessment to groundwater of pit latrine rural sanitation policy in developing country settings. In: Science of the Total Environment. 2018 ; Vol. 613-614. pp. 592-610.
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Back, JO, Rivett, MO, Hinz, LB, Mackay, N, Wanangwa, GJ, Phiri, OL, Songola, CE, Thomas, MAS, Kumwenda, S, Nhlema, M, Miller, AVM & Kalin, RM 2018, 'Risk assessment to groundwater of pit latrine rural sanitation policy in developing country settings' Science of the Total Environment, vol. 613-614, pp. 592-610. https://doi.org/10.1016/j.scitotenv.2017.09.071

Risk assessment to groundwater of pit latrine rural sanitation policy in developing country settings. / Back, Jan O.; Rivett, Michael O.; Hinz, Laura B.; Mackay, Nyree; Wanangwa, Gift J.; Phiri, Owen L.; Songola, Chrispine Emmanuel; Thomas, Mavuto A.S.; Kumwenda, Steve; Nhlema, Muthi; Miller, Alexandra V.M.; Kalin, Robert M.

In: Science of the Total Environment, Vol. 613-614, 01.02.2018, p. 592-610.

Research output: Contribution to journalArticle

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AU - Back, Jan O.

AU - Rivett, Michael O.

AU - Hinz, Laura B.

AU - Mackay, Nyree

AU - Wanangwa, Gift J.

AU - Phiri, Owen L.

AU - Songola, Chrispine Emmanuel

AU - Thomas, Mavuto A.S.

AU - Kumwenda, Steve

AU - Nhlema, Muthi

AU - Miller, Alexandra V.M.

AU - Kalin, Robert M.

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KW - risk

KW - groundwater quality

KW - sanitation

KW - Millennium development goals

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