Anthropogenic impacts on water quality of the lagoonal coast of Fongafale Islet, Funafuti Atoll, Tuvalu

Abstract

Water pollution, evident by negative values of redox potential in waters, occurs at the lagoonal coast located near the densely populated area of Fongafale Islet on Funafuti Atoll, Tuvalu, Central Pacific. Sediment microbial quinone analysis revealed that these coastal sediments exhibit 2.7-10.4 times more microbial biomass, significantly different microbial community structure and low microbial diversity, when compared to an undisturbed natural coastal sediment. Thus, the pollution is chronic. By considering the total land use/coverage on the islet, the situation of septic tank installations, temporal changes in water redox potential and Escherichia coli numbers in the coastal waters and the spatial distribution of acid volatile sulfide in the sediments, we conclude that domestic wastewater is the primary source of pollution. This pollution is proposed to occur via the following mechanism: during ebb tides, domestic wastewater leaking from bottomless septic tanks and pit toilets run off into the lagoonal coast. Tide changes control the pollution load of domestic wastewater.

Temporal and thematic trends in water, sanitation and hygiene (WaSH) research in Pacific Island Countries: a systematic review

“…Most public health studies fit into four categories: linking disease prevalence with animal husbandry and zoonotic pathogens (Owen 2005;Berlioz-Arthaud et al 2007;Guerrier et al 2013), personal hygiene (Larsen 1995;Tran et al 2006;Greenwell et al 2013), seasonal variability (Warner et al 2007;Perez et al 2011;Choudhary et al 2012), and poor sanitation (Bukenya & Nwokolo 1991;Horwood & Greenhill 2012;Fujita et al 2013). …”

“…Papers discussing the link between freshwater lenses and WaSH focused on excessive or inappropriate methods of water extraction (Ghassemi et al 1990;Griggs & Peterson 1993;Koda et al 2013), climate change (Storey & Hunter 2010;Terry & Falkland 2010;Nakada et al 2012), drought (Terry et al 2001;White et al 2007;) and saline intrusion (Ghassemi et al 1990;Griggs & Peterson 1993;Koda et al 2013). Given Environmental pollution, especially from sanitation (Duwig et al 1998;Wen 2011;Fujita et al 2013) and solid waste management (Carden 2003), received some attention in the literature. Bottomless septic tanks and pit toilets have been implicated in faecal pollution (Fujita et al 2013;Fujita et al 2014), although 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 there was little research on the environmental impacts of open defecati...…”

Social–ecological change and implications for food security in Funafuti, Tuvalu

“…Finally, secondary sources relevant to both social and ecological factors were analyzed. The Government of Tuvalu's Household Income of Expenditure Survey (2010) provided insights on household food purchasing and production, and the academic articles from environment science disciplines (e.g., Fujita et al 2013) provided insight into the way in which domestic wastewater pollution is impacting the condition of the reef fishery in the Funafuti lagoon.…”

“…Subsistence fishing is conducted primarily inshore using nets, spears, and rods, and 64% of respondents said that a member of their household went fishing at least once monthly in the past year. Yet the quality of the inshore fishery has declined in recent years owing to pollution from the discharge of domestic wastewater and leaching from open-pit dumping (Fujita et al 2013(Fujita et al , 2014, as well as overfishing (Sauni and Fay-Sauni 2005).…”

“…The condition of the Funafuti lagoon has declined dramatically in recent years. Ecological factors such as domestic wastewater pollution (Fujita et al 2013) and overfishing (Key Informant 16, personal communication, 10 October 2013), together with climatic conditions like sea-surface temperature and ocean acidification, have already negatively affected reef fisheries (Kuchinke et al 2014), as is evident by the decreased availability, size, and quality (i.e., ciguatera contamination) of fish from the lagoon. One key informant, a fisherman who has been fishing in Funafuti since 1983, described that there are much fewer fish in the lagoon than in past: Fishermen and household survey respondents alike also described that fish from the lagoon are much smaller than they were in the past, and that fish are more frequently contaminated with ciguatera.…”