The pit latrine paradox in low-income settings: A sanitation technology of choice or a pollution hotspot?

• Published in: The Science of the total environment 2023-06, Vol.879, p.163179-163179, Article 163179
• Main Authors: Gwenzi, Willis, Marumure, Jerikias, Makuvara, Zakio, Simbanegavi, Tinoziva T., Njomou-Ngounou, Emma Laureane, Nya, Esther Laurentine, Kaetzl, Korbinian, Noubactep, Chicgoua, Rzymski, Piotr
• Format: Article
• Language: English
• Subjects: Conventional contaminants; COVID-19; Emerging contaminants; Future research directions; Greenhouse gas emissions; Human pathogens; Humans; Hygiene; Menstruation; Pesticides; Pharmaceutical Preparations; Sanitation; Toilet Facilities; ‘Catch-all’ disposal receptacle
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.163179

Pit latrines are widely promoted to improve sanitation in low-income settings, but their pollution and health risks receive cursory attention. The present narrative review presents the pit latrine paradox; (1) the pit latrine is considered a sanitation technology of choice to safeguard human health, and (2) conversely, pit latrines are pollution and health risk hotspots. Evidence shows that the pit latrine is a ‘catch-all’ receptacle for household disposal of hazardous waste, including; (1) medical wastes (COVID-19 PPE, pharmaceuticals, placenta, used condoms), (2) pesticides and pesticide containers, (3) menstrual hygiene wastes (e.g., sanitary pads), and (4) electronic wastes (batteries). Pit latrines serve as hotspot reservoirs that receive, harbour, and then transmit the following into the environment; (1) conventional contaminants (nitrates, phosphates, pesticides), (2) emerging contaminants (pharmaceuticals and personal care products, antibiotic resistance), and (3) indicator organisms, and human bacterial and viral pathogens, and disease vectors (rodents, houseflies, bats). As greenhouse gas emission hotspots, pit latrines contribute 3.3 to 9.4 Tg/year of methane, but this could be an under-estimation. Contaminants in pit latrines may migrate into surface water, and groundwater systems serving as drinking water sources and pose human health risks. In turn, this culminates into the pit latrine-groundwater-human continuum or connectivity, mediated via water and contaminant migration. Human health risks of pit latrines, a critique of current evidence, and current and emerging mitigation measures are presented, including isolation distance, hydraulic liners/ barriers, ecological sanitation, and the concept of a circular bioeconomy. Finally, future research directions on the epidemiology and fate of contaminants in pit latrines are presented. The pit latrine paradox is not meant to downplay pit latrines' role or promote open defaecation. Rather, it seeks to stimulate discussion and research to refine the technology to enhance its functionality while mitigating pollution and health risks. [Display omitted] •History and use of pit latrines as a low-cost sanitation technology are discussed.•Pit latrines are hotspots for legacy and emerging pollutants and greenhouse gases.•Water and pollutant flows create a pit latrine-groundwater connectivity/continuum.•Human exposure and health risks, risk factors, and high-risk settings are discussed.•Current and emerging