Derwent Estuary Ambient Water Quality monitoring program - Site U3

Site U3 is sampled monthly by Nyrstar Hobart as part of the Derwent Ambient Water Quality monitoring program. Since 2003, ambient water quality monitoring has been carried out on a monthly basis at up to 28 sites throughout the Derwent estuary by Norske Skog Boyer, Nyrstar Hobart and the State Government. Monitoring is carried out by three different boat-based sampling parties, but is co-ordinated to occur on the same day each month. At each site, in-situ field measurements are taken using calibrated sensors for temperature, salinity, pH, dissolved oxygen and turbidity. Water clarity is also measured using a secchi disk. Surface and bottom water samples are collected for analysis of true color, total suspended solids(TSS), total and dissolved nutrients, organic carbon and zinc. at most sites, depth integrated samples are also collected for chlorophyll a using a plastic tube. Bottom samples in the Middle and Outer estuary are collected using a niskin bottle. Pumps are used in the upper estuary site to fill up the bottles. All water samples are analysed at Analytical Service Tasmania, a National Association of Testing Authorities-accredited laboratory. Monitoring site depth is 2 meters