Effects of greywater irrigation on germination, growth and photosynthetic characteristics in selected African leafy vegetables

The reuse of greywater, wastewater from sources other than toilets, could enable low-income  households to save potable water for drinking and cooking. Greywater irrigation of food crops is widely practised but its effects on African leafy vegetables (ALVs), which hold potential for cultivation to improve food security, are unknown. This study investigated the effects of synthetic greywater  irrigation on germination in three ALVs, viz., Amaranthus dubius, Cleome gynandra and Solanum nigrum, and subsequent seedling growth in A. dubius and S. nigrum. Seeds and seedlings were treated with chlorinated and dechlorinated greywater and tap water, supplemented with nutrients. Greywater application decreased germination capacity (by 23–25%) when assessed in Petri dishes in A. dubius only. However, greywater application was less harmful to A. dubius seeds sown in soil. Vigour was compromised in greywater-treated seeds of all three species but greywater can be used to irrigate freshly-sown seeds of A. dubius without reducing percentage seedling production. However, greywater irrigation reduced capacity (by 21–23%) and rate of shoot emergence in S. nigrum, and growth and chlorophyll content in both species. These negative effects were accompanied by increased soil  electrical conductivity (after 21 d) and pH (after 14 d). The reduced growth under greywater irrigation was most likely based on a reduction in light-harvesting capacity and/or nutrient availability. Overall, S. nigrum seedlings were significantly more sensitive to the negative effects of greywater, possibly due to increased transpirational water loss under greywater irrigation. The effects of greywater were largely independent of chlorine content. Applying greywater in excess of plant requirements and/or alternating greywater irrigation events with freshwater watering events could promote leaching of salts found in greywater. The effects of greywater irrigation on soil water and nutrient availability demand further investigation for ALVs.Keywords: African leafy vegetables, greywater irrigation, germination, seedling growt

Development of guidance for sustainable irrigation use of greywater in gardens and small-scale agriculture in South Africa

Greywater is untreated household effluent from baths, showers, kitchen and hand-wash basins and laundry (i.e. all non-toilet uses). More than half of indoor household water is normally used for these purposes and can potentially be intercepted by the householder for additional beneficial uses. Greywater use is practised on an informal basis to supplement irrigation water, either in urban gardens in middle- to upper-income suburbs or in food gardens in lower-income informal, periurban and rural areas. It holds the potential to contribute significantly to food security in poor settlements by providing a source of both irrigation water and nutrients for crop plants. However, there are presently no formal guidelines for the use of greywater in South Africa. This paper presents the rationale and framework of a guidance document for the sustainable use of greywater to irrigate gardens and small-scale agriculture in South Africa, developed under the auspices of the Water Research Commission. The 3 driving principles in developing this guidance were: protection of human health; protection of plants irrigated; and protection of soil and the environment. Risk-management scenarios were developed on the basis of the extent of greywater characterisation. Water-quality constituents for inclusion were selected from among those indicated as presenting a problem in previous studies. Guidance was provided for managing greywater quality, either by mitigation of greywater quality (by practices such as irrigation method, amelioration of soil, leaching of soil and planting of tolerant plant types) or by small-scale biological treatment of greywater. Guidance was also given regarding the volumes of greywaterwhich can be applied, together with factors to adjust these volumes for site-specific conditions.Keywords: greywater, irrigation, food security, sustainable agriculture, health, soil, plant growt

Rectal perforation from colonic irrigation administered by alternative practitioners

The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included.Doug V. Handley, Nick A. Rieger and David J. Rodd

Water security in South Africa: perceptions on public expectations and municipal obligations, governance and water re-use

South Africa is a water-scarce country with increasing pressure on its water resources. Urgent interventions are needed to protect water security within this rapidly developing country. This paper reports on an interdisciplinary Water Security Colloquium, convened by the South African Young Academy of Science in 2014. A selected group of water professionals from academia, civil society and local government was brought together to discuss water security under three focus themes: ‘public expectations and municipal obligations’, ‘water security and governance: challenges and advances’, and ‘water re-use: health and infrastructural considerations’. Participant perceptions were generated using a focus group methodology, combined with participatory data collection methods. Under each theme, inputs were categorised as ‘challenges’, ‘gaps in knowledge’, and ‘solutions/recommendations’ and these inputs were thereafter ranked in order of importance via a ‘voting’ process. Major challenges perceived included a lack of both skills and political will in government, a need to restore citizen trust in government intention and capability to deliver water-related services, and a failure to up-scale existing water re-use technology. Participants identified understanding of the process and implications of the Green and Blue Drop Programmes, knowledge transfer to the public, and the role of educators as major knowledge gaps. The top suggestions proposed included creating public awareness around and buy-in to initiatives to improve water security, accessible and user-friendly conversion of research results to implementation, and ensuring an active role for educators in creating awareness around water security. In view of the concerns identified, participants suggested as potential solutions: improving government and public understanding around water issues, incentivising water re-use and conservation, introducing rising block tariffs and improving human capacity development in the water sector. Developing the ecological infrastructure that protects both quantity and quality of water and building strong partnerships among all stakeholders were also recognised as key.Keywords: capacity development, education, governance, water security, water re-use, water conservation, local governmen

Microbial quality of drinking water from groundtanks and tankers at source and point-of-use in eThekwini Municipality, South Africa, and its relationship to health outcomes

Drinking water quality was investigated at source and corresponding point-of-use in 2 peri-urban areas receiving drinking water either by communal water tanker or by delivery directly from the distribution system to household-based groundtanks with taps. Water quality variables measured were heterotrophic bacteria, total coliforms, E. coli, conductivity, turbidity, pH, and total and residual chlorine. Water quality data were analysed together with an existing epidemiological database to investigate links between microbial quality of drinking water, household demographics, health outcomes, socio-economic status, hygiene and sanitation practices. Groundtank households had better quality drinking water than households using storage containers filled from communal tankers. Uncovered storage containers had the poorest microbial water quality among all storage containers. All stored water did not meet drinking water standards, although mains water did. Households with children under 5 years and using open-topped containers had the poorest water quality overall. Households with groundtanks had the best water quality at point-of-use, but did not have the lowest occurrence of health effects. Although groundtanks were supplied together with urine diversion (UD) toilets and hygiene education, groundtank households showed overall poorer hygiene practices than tanker-supplied households, and some groundtank households with UD toilets preferred to continue using open defecation. Households that practised open defecation had higher levels of E. coli in their drinking water and higher rates of adverse health outcomes. Poorer socio-economic standing and lower educational standard were associated with poorer water quality, poorer hygiene practices and higher rates of diarrhoea and vomiting.Keywords: drinking water; point of use; water quality; water quantity; hygiene; sanitatio