In this paper, we investigate the current water quality of the densely populated lagoonal coasts in Fongafale Islet, Central Pacific and the occurrence of water pollution. Ricolinostat We then compare them with less populated natural coast in the islet. The primary pollution sources and pollution mechanism are identified. Through this investigation, we demonstrate the need for effective water quality control measures for coastal conservation. Materials and methods Study area Field surveys were conducted on Fongafale Islet (8°31′S, 179°12′E) in April and August 2010, and January and August 2011. The islet is located on Funafuti Atoll, Tuvalu, a lagoon of ~18 km

in diameter (Fig. 1a, b). Fongafale Islet is the capital of Tuvalu and the largest settlement in this country. Approximately 4,492 people live on Funafuti Atoll and 9,561 live in Tuvalu (Secretariat of the Pacific Community 2005). Six sampling points were selected on the lagoon side of Fongafale Islet (Fig. 1c). Site 1 is near the southern

tip, where there are no nearby inhabitants. Thus, this site is considered to be very close to an undisturbed natural environment. Sites 2-1, 2-2, 2-3 and 2-4 are along a densely populated area (Yamano et al. 2007). Site 3 is a medium populated area, which is located ~5 km north of site 2-2. All sites are ~15 m from the shore of the lagoonal coast. Surface current flows north-ward along Fongafale Islet at both neap https://www.selleckchem.com/products/Vorinostat-saha.html and spring tides and the current speed is less than 0.1 m/s (Damlamian 2008). Fig. 1 Maps of the study area. a Tuvalu, b Funafuti Atoll, c observation

sites in Fongafale Islet Seawater analyses Water quality measurements A water quality sonde (Model 6600V2, YSI/Nanotech, Kawasaki, Japan) was installed at ~20 cm from the reef-flat sediment and at 40–60 cm water depth at sites 1, 2-2 and 3, on 5, 3 and 4 April 2010, respectively. Water temperature, electrical conductivity (EC), salinity, dissolved oxygen (DO), pH and redox potential PRKACG (Eh) were observed routinely at intervals of 10 min for around 1 day on the same days. Further observation was conducted at site 2-2 from 6 to 10 August 2010 at the same intervals for 4 days, in order to investigate the behavior of domestic wastewater runoff. Escherichia coli Escherichia coli is a coliform bacterium found most commonly in fecal material, more so than other fecal coliform genera (Metcalf and Eddy 2003). Surface waters were sampled in selleck products triplicate (250 mL) at all sites at about 0930 hours (low tide) and at about 1530 hours (high tide) on 27 August 2011. To understand wastewater runoff mechanisms, continuous observation of E. coli was performed every 1–2 h in a similar way at site 2-2 on 7 August 2010 and 29 August 2011. The former observation date was between neap tide and the following spring tide, and the latter was just after spring tide (Fig. 2).