Year 2013 STATE OF THE DERWENT Report Card POLLUTION SOURCES, LOADS AND TRENDS

SEDIMENT: total suspended sediment (TSS) Pollution enters the Derwent from Industries have historically been the THE DERWENT ESTUARY MANAGEMENT AND ENVIRONMENTAL estimated cumulative loads 2003-12 RESTORATION MONITORING AND 30000 many sources, commonly referred to as largest point sources of organic matter The Derwent estuary lies at the heart of REPORTING 25000 ‘point sources’ and ‘diffuse sources’. Point and heavy metals to the estuary; however the metropolitan area and is a The Derwent Estuary Program (DEP) 20000 Industry sources include sewage treatment plants inputs of these pollutants have declined 15000 waterway of great natural beauty and was established in 1999 as a partnership A fundamental requirement for WWTPs 10000 Stormwater and large industries, such as the Norske significantly in recent years. Since 2007, diversity. Named after the Celtic word to restore and protect the Derwent effective natural resource management tonnes/year 5000 Skog paper mill at Boyer and Nyrstar organic loads from the Norske Skog ‘clear water’ in 1794, the Derwent is estuary. The program has been is an on-going and reliable source of 0 Hobart smelter at Lutana. paper mill have fallen by over 95%. At the an integral part of ’s cultural, successful in bringing together a wide environmental data. This principle 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Nyrstar Hobart smelter, projects to collect economic and natural heritage. The range of stakeholders – firstly to build forms the basis of the DEP’s cooperative Diffuse sources include stormwater and treat contaminated groundwater estuary is an important and productive a common understanding, vision and monitoring program between the runoff from urban areas and the ORGANIC MATTER: biochemical oxygen demand (BOD) captured 105 tonnes of zinc and other ecosystem and supports a wide range of management framework – and secondly state government, councils, industries estimated cumulative loads 2003-12 larger catchment inputs carried by 10000 heavy metals in 2012, and all stormwater habitats and species. to progressively implement this vision and research institutes. Formerly the Derwent and Jordan . Other discharges from the site were successfully through partnership agreements and independent monitoring programs are Industry diffuse pollutant sources include landfills 5000 WWTPs intercepted and treated. practical actions. now coordinated so as to provide better and contaminated sites, air pollution, tonnes/year information on the estuary as a whole, aquaculture operations, and wastes Urban stormwater contributes the The program was initially designed to 0 and to report annually on environmental 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 associated with shipping, ports and majority of faecal bacteria to the estuary, address environmental quality issues such conditions and trends in the Derwent. marinas. Sediments within the estuary derived from animal droppings, aging as industrial and urban water pollution, itself may also release pollutants into the infrastructure, sewage overflows, and contaminated sediments, introduced NUTRIENTS: total nitrogen (TN) overlying waters under certain conditions. cross connections between the sewage species and loss of estuarine ecosystems. estimated cumulative loads 2003-12 1800 and stormwater systems. Stormwater is More recently, foreshore issues have 1600 Contaminants released or transported 1400 also the main source of litter. 1200 Approximately 40% of Tasmania’s also been included within the program. Industry into the Derwent from these various 1000 WWTPs population - 216,000 people - live around Key aspects of implementation include 800 sources include pathogens, nutrients, Catchment and Channel: Recent studies 600 Stormwater tonnes/year the estuary’s margins. The Derwent is environmental monitoring and reporting, 400 River organic matter, silt, litter and a range of suggest that diffuse inputs of nutrients 200 widely used for recreation, boating, coordination of regional activities, and 0 toxicants including heavy metals, resin from both the catchment 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 fishing, marine transport and industry. implementation of priority projects such acids and hydrocarbons. and the D’Entrecasteaux Channel play a key role in the health of the estuary. Further upstream, the River Derwent as stormwater management, heavy metal Sewage treatment plants are the largest The amount of water released from the supplies the majority of the region’s remediation and conservation of key This ‘Report Card’ summarises monitoring NUTRIENTS: total phosporous (TP) point sources of bioavailable nutrients to drinking water supply and is a major estuarine habitats and species. data collected by the DEP and our estimated cumulative loads 2003-12 catchment is also an important factor 250 the estuary. In 2012, discharges of treated for both water quality and ecosystem source of hydroelectric power. partners, as well as other relevant 200 sewage effluent decreased by about 19%, The DEP is supported by the Tasmanian Industry information collected during 2012 and the 150 health. To better understand current A number of environmental issues affect Government, six councils that border WWTPs and associated nutrients, TSS and BOD 100 Stormwater conditions and trends, a detailed review start of 2013, including: tonnes/year the Derwent estuary, in particular: on the estuary (Brighton, Clarence, River also declined by an estimated 4% to 16%. 50 of D’Entrecasteaux Channel water quality • weekly recreational water quality Effluent reuse to support agriculture and • heavy metal contamination; Derwent Valley, Glenorchy, Hobart and 0 testing during summer months; 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 data was carried out in 2012 (see below). • poor recreational water quality at Kingborough Councils) and five business other beneficial uses increased slightly in • monthly whole-of-estuary water some bays and beaches; partners (Nyrstar Hobart, Norske Skog 2012 to 11% of the total effluent produced quality monitoring; • low oxygen levels in the upper estuary Boyer, Tas Water, TasPorts and Hydro in the metropolitan area. • surveys of heavy metal levels in fish NUTRIENTS: dissolved inorganic nitrogen (DIN) during summer; Tasmania). Other project partners include estimated cumulative loads 2003-12 and shellfish; 700 • locally elevated nutrient levels; the , University 600 D’ENTRECASTEAUX CHANNEL PARTNERSHIP 500 of Tasmania, CSIRO, NRM South, local • biological surveys (little penguins, Industry The D’Entrecasteaux Channel and Huon Estuary are areas of great beauty and biodiversity, and • low summer flows and barriers to fish 400 WWTPs businesses and community groups. spotted ) ; and 300 Stormwater an important centre for population growth, marine farming and recreational boating and fishing. migration; tonnes/year 200 River The Channel also has a strong influence on the Derwent estuary, as there is a net flow of seawater • weed surveys and control actions (rice 100 • introduced marine pests and weeds; In 2010, the DEP was awarded ’s from the Channel into the Derwent. In 2012, the D’Entrecasteaux Channel Project was launched grass, karamu). 0 • loss of habitats and species; and National Riverprize for excellence in river 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 as an initiative of Kingborough and Councils, Southern Water, Tassal and Huon Aquaculture, NRM South and the DEP. The DEP’s role in the project is to provide technical and • impacts of climate change, e.g. management. More detailed information is published in financial support, including a $50,000 grant awarded through the International RiverFoundation’s erosion, flooding and habitat loss five-yearly State of the Derwent Estuary Twinning Program. reports, available on our website: HEAVY METALS (Zn and Cd) Although there have been significant The main objectives of the project are to: www.derwentestuary.org.au Capture from groundwater at Nyrstar improvements in the treatment of sewage 140 • Promote the values of the Channel and lower Huon Estuary 120 • Bring together existing science to better understand the waterways and industrial wastes over the past 100 • Improve the availability of information on the waterways to all stakeholders decade, the Derwent still faces a number 80 • Initiate a collaborative approach to managing the Channel and lower Huon Estuary that 60

of environmental challenges. A strategic tonnes/year 40 addresses the full range of uses and issues and coordinated planning approach 20 The Project was formally launched in December 2012, followed by publication of the State of the 0 D’Entrecasteaux and lower Huon Estuary 2012. This report provides a comprehensive review of across all levels of government, industry 2006-072007-08 2008-09 2009-102010-112011-122012-13 environmental data for the period from 1999 to 2012, and is a valuable resource for managers, and the community is our best hope for a scientists and the community. For more information about the project, including reports, see clean and healthy estuary in the future. www.kingborough.tas.gov.au/page.aspx?u=660

DERWENT WATER AND SEDIMENT QUALITY DERWENT HABITAT AND SPECIES

CLIMATE IN 2012 WATER QUALITY Although nutrient enrichment and HEAVY METALS IN ESTUARINE HABITAT & MARINE PESTS AND WEEDS INDICATORS nuisance algal blooms have not been a SEAFOOD SPECIES Hobart rainfall in 2012 was 15% lower The Derwent estuary is extensively significant issue in the Derwent to date, than average, resulting in lower river and The DEP coordinates a whole-of-estuary Oysters and mussels from the Derwent Surveys of estuarine habitats indicate that colonised by introduced marine species. there are some indications of increasing stormwater flows, and consequently, monitoring program that integrates contain high levels of heavy metals, unvegetated, soft-bottom habitats are At least 79 introduced species have been bioavailable nutrients in the upper lower levels of faecal bacteria, sediments, sampling carried out by the DEP and EPA particularly zinc, lead and cadmium. by far the most abundant habitats in the recorded, including 4 that have National estuary. This may be related to changes nutrients and litter. Division, Nyrstar Hobart, Norske Skog While levels appear to have declined estuary (86%), followed by seagrass and Control Plans: northern Pacific seastar, in river flows and catchment land use, as and TasWater. Water quality is monitored since 2003 in some areas (i.e. above the macrophytes (7%; primarily in the upper European green crab, Japanese seaweed, well as point and diffuse nutrient sources. SWIMMING IN THE each month at 27 sites for indicators ), they are still far in excess estuary), tidal sandflats (6%; primarily and European clam. A number of other Continued monitoring of water quality, DERWENT such as temperature, salinity, dissolved of national food standards. in Ralphs Bay) and rocky reefs (1%; species (e.g. New Zealand half crab, New and seagrass/macrophyte beds oxygen, suspended solids, nutrients, primarily in the lower estuary). Zealand seastar, and New Zealand screw Each summer, recreational water quality are recommended to better understand Mercury levels exceed national food organic carbon, chlorophyll a and zinc. shell) also pose a significant threat to the is monitored at about 35 beaches and and prevent adverse impacts. standards in several species of Derwent- This information is used to document ecology of the estuary. bays around the estuary through a caught fish – particularly black bream – conditions and trends over time and to collaborative State and Local Government and to a lesser degree flathead and trout. Rice grass – an invasive intertidal weed provide data for estuarine modelling and program. Sampling is conducted weekly Limited sampling suggests that levels are – has been successfully managed in the process studies. from December through March, at the lower in other recreationally-targeted fish Derwent through annual surveys and locations shown on the map overleaf. Dissolved oxygen levels in the Derwent (e.g. whiting, Australian salmon, mullet, control actions, and the area of infestation To describe the risk level to swimmers a are generally high except periodically in cod and flounder). had been reduced from two hectares in colour coded system is used based on 5 the area between Bridgewater and New 1995 to zero in 2009 and 2010. However Median mercury levels in Derwent-caught years of monitoring data: green indicates Norfolk. During summer months when the 2011 and 2012 surveys found several flathead decreased slightly in 2012; good, yellow indicates fair and red water temperatures are high and river small patches in the middle estuary region. however there is considerable variability Surveys of several Derwent estuary indicates poor water quality. flows are low, the deeper channels in this These have been treated, and will continue CONTAMINATED from year to year. A recent PhD study colonies continued in area tend to be oxygen poor, with adverse to be monitored. Eight of the Derwent’s 18 swimming SEDIMENTS at the suggests 2012, with varied results. In particular, impacts on bottom-dwelling organisms. sites are classified as having good water that much of this variability is related the number of handfish at the Battery During 2012, the DEP also continued to Low oxygen levels can also result in the Levels of heavy metals in Derwent estuary quality, seven are fair and three are poor. to fish length, age and regional growth Point site appeared to be stable or survey and treat a major infestation of release of nutrients and heavy metals sediments are among the highest in The highest rated sites are at Opossum rates, and that changes to the monitoring increasing, while numbers at Sandy Bay karamu – a recently introduced woody from underlying sediments. Australia. Derwent sediments tend to Bay, Hinsby, , Kingston beach design may be warranted. may have declined. Numbers of juvenile weed from New Zealand. Karamu is be fine-grained and organic-rich and (middle), and Little Howrah New Norfolk fish at all sites are critically low and over a serious threat to the upper Derwent Dissolved Oxygen at Depth significantly exceed national sediment There has been no change in current beach. Windermere beach, the western 16 2000 artificial spawning substrates have wetlands, and had spread 5 km down-river 14 quality guidelines for zinc, copper, health advice, which is outlined in the end of Nutgrove beach and middle of 12 been planted out at key sites to improve from New Norfolk. A containment line has mercury, lead, cadmium and arsenic. The DEP’s information pamphlet Should I Eat Howrah beach received poor water 10 breeding success. now been established near Boyer and over 8 DEP’s ten-yearly sediment survey was Shellfish and Fish from the Derwent? Key quality ratings. 6 2000 karamu plants were treated in Nov/

Concentration (mg/L) 4 carried out in 2011 – see text box below advice from the Director of Public Health 2 Dec, pushing the containment line further Of the 19 bays, coves and other sites for key findings. is as follows: 0 upstream. monitored, six have good water quality, 01/01/06 13/02/08 27/06/09 09/11/1023/03/12 • Don’t eat shellfish collected from four are fair and nine are poor (in the Derwent (including Ralphs Bay) particular at , Marieville DERWENT ESTUARY SEDIMENT QUALITY SURVEY • Don’t eat any bream from the CLIMATE CHANGE Esplanade, Lindisfarne Bay, In 2011 the DEP completed a survey of Derwent estuary sediments to assess any changes, as Derwent and Browns River and Geilston Bay). Regional risks associated with climate compared to a similar survey carried out in 2000. Samples were collected at 123 sites between • Limit consumption of other change include inundation of low-lying Several investigations commenced in New Norfolk and the Iron Pot Light and surface sediments were analysed for levels of heavy Derwent-caught fish to no Antonia Cooper coastal communities and infrastructure, 2012/13 to identify pollution sources metals and organic matter. The results suggest that while levels remain high, there has been more than 2 meals/week, or 1 as well as the loss of critical estuarine at beaches with poor water quality, Monitoring of Derwent little penguin a decrease in some of the extreme levels of zinc, lead, cadmium and mercury at mid estuary meal/week for pregnant and ecosystems. Areas of particular with a focus on stormwater run-off and colonies suggests an improvement in the sites. For example, the maximum recorded level of zinc in the 2000 survey was 59,000 mg/ breastfeeding women, women vulnerability in the Derwent area include sewerage infrastructure, and further work number of breeding pairs with at least 111 kg as compared to 14,600 mg/kg in 2011. There have also been some slight shifts in the areas planning to become pregnant and coastal roads, sewerage and stormwater is planned in 2013/14. pairs recorded, an improvement on 2010, of contamination, with lower levels found in the upper estuary and Ralphs Bay areas, and young children systems, and low-lying rubbish tips and and particularly 2011, when 25 birds were Most urban areas experience poor somewhat higher levels in Elwick Bay. It important to note that reductions in sediment metal landfills. Estuarine habitats are also at killed in a single dog attack. Councils, water quality after heavy rain. levels probably reflect a combination of improved site practices (e.g. covering or reprocessing of NO BREAM NO SHELLFISH risk from sea level rise, particularly tidal community groups and DEP staff have Swimming is not recommended in stockpiles at Nyrstar) together with the on-going natural burial of contaminated sediments with wetlands, saltmarshes and tidal flats, along continued to enhance key sites through the Derwent for several days after relatively cleaner sediments. Sediment cores collected at sites around the Derwent have shown with the birds, fish and other fauna that revegetation, fencing and signage, as well heavy rain and never in the vicinity of that the highest metal levels are now typically found at a depth of 20 or more centimetres. This depend on these habitats. as installation of artificial burrows. stormwater drains or urban rivulets. is an important consideration in managing any proposed projects in the Derwent that involve dredging or other sediment disturbance. RECENT MANAGEMENT ACTIONS, Program partners: SAMPLING SITES AND DISCHARGE POINTS TasWater

River

New New OIL SPILL PREVENTION AT HYDRO DAMS Norfolk Bridgewater Norfolk Norske Skog is progressively implementing oil management plans Paper Bridgewater at power stations across the state to minimise the risk of oil loss from Causeway their infrastructure, and any impacts as a result of a spill. Planning and Jordan site preparation are now underway at Meadowbank Power Station Bridgewater (on the Derwent River above New Norfolk), where the design and GREATER HOBART TRAILS WEBSITE operation of the 40 year old Kaplan turbine would make trapping Keen for a walk, bike or horse ride around Hobart? Not sure where to go, or would like to try something new? The new Greater spilled oil difficult. The turbine is undergoing a major refurbishment Hobart Trails website, which is smart phone and ipad friendly, lists 79 trails in the Hobart region to help you do just that. The and will be upgraded to an innovative oil-less design which will website, containing content generously provided by Hobart, Kingborough, Clarence, Derwent Valley, Glenorchy and Clarence significantly reduce the risk of an oil spill. Other oil management City Councils, can be used in a number of ways. There is an interactive map if you’re interested in finding a walk in your local improvements include; improved bunding around transformers; an area, or if you have limited time, you can choose a walk based on its duration. Search options also cater for people looking for upgrade of site specific equipment to support oil spill response; and walks with dogs, prams, wheelchairs, or trails for bicycles, mountain bikes or horses. Another key feature is weather information, replacing aged or inadequate oil pipe supports, valves or fittings to as each track has a real-time link to the closest weather station – provided by the Bureau of Meteorology. reduce failure risk. Site specific oil spill response plans are now in place www.greaterhobarttrails.com.au for all Hydro Tasmania’s power stations. Austins Ferry Derwent River Catchment NEW SEAFOOD SAFETY SIGNS Is it safe to eat fishand shellfish from the Derwent estuary, FOR THE DERWENT Old Beach including Ralphs Bay and Browns River? New signs installed around the Derwent

DO NOT EAT ANY BREAM DO NOT EAT ANY SHELLFISH reiterate health advice about eating fish and Claremont by Peter Gouldthorpe BL10724 Fish illustrations shellfish from the Derwent estuary. The signs at 32 locations from New Norfolk to South Arm National Agriculture Parks and Tinderbox remind members of the public

LIMIT CONSUMPTION of FLATHEAD not to eat bream or shellfish from the Derwent, Dogshear and OTHER DERWENT-CAUGHT FISH Point and to limit consumption of other Derwent Fish caught fish. See the seafood safety section Farming For details see R E V I R Cameron www.derwentestuary.org.au/seafood-safety (overleaf) for further details about current

Agriculture For more information: Bay Public and Environmental Health public health advice on Derwent caught fish www.publichealthalerts.tas.gov.au Public Health Hotline 1800 671 738 and shellfish.

Logging STORMWATER POLLUTION REMOVAL AT WINDERMERE BAY Bowen In 2012/13 a new stormwater treatment system was Bridge Water Treatment built at the Windermere Bay foreshore reserve based Plant on water sensitive urban design principles. The system was designed to remove litter, sediments, heavy metals, East Area 4 Upper Estuary oils and nutrients from a 10 hectare catchment that GLENORCHY includes the nearby Claremont shopping centre, while Risdon also improving the amenity of the foreshore park. Prince Of Wales Bay Features of the system include a gross pollutant trap, Nyrstar DUCKHOLE DAM BOOSTS RECYCLED permeable rock walls and areas populated with Hobart Smelter Factory Catchment WATER SUPPLIES runoff native plants. The stormwater is filtered through this Septic The South East Tasmania Recycled Water Scheme – Wetlands runoff ‘treatment train’ where plants and microscopic animals Moonah currently operated by TasWater – was designed to reduce AY in the soil provide additional treatment before it is Stormwater Sewage outfalls the discharge of treated sewage effluent into the Derwent. outfall released to the Derwent. This project was funded through Industrial Selfs Point effluent Swimming The scheme is supplied mainly from the Rosny and Mudflats Recreational the Australian Government’s Caring for Our Country TER CAUSEW (outfall at Sandy Bay) fishing Rokeby sewage treatment plants and currently supplies 27 Hydraulic Water sports program with additional support by the Glenorchy City Swimming links New Town Lindisfarne NEW NORFOL K Council. Consultants Syrinx designed and constructed the customers including golf courses, broad-acre cropping and BRIDGE WA INPUTS Freshwater Cornelian River Plankton and vineyards. Demand for the water now exceeds supply, so in • sediment stormwater treatment system, and volunteers from the flow Resident and natural bacteria • litter migratory fish Exchange with Bay 2012/13 the 1000 megalitre Duckhole Dam was constructed • nutrients mid estuary Understorey Network grew 6000 native plants for the site. • oil Seagrass near Richmond to act as a winter storage. The new dam (modified) • heavy metals • faecal bacteria Seawater Fresh river water will complement the existing 650ML of on-farm storage and

mixing Salt water assist in improving the reliability of supply to customers Microscopic sediment Area Tasman water algae and natural bacteria 4 during peak irrigation periods. The dam will also reduce • nutrients 3 HOBART Bridge • organic matter cycling • heavy metals Oxygen depletion the impacts of salt water infiltration in the Rosny Sewage sediment Bottom 2 1 Macquarie Sulpherous gas dwelling Sludge and organic organisms Poin t Treatment Plant catchment, providing a higher quality rich sediments Rosny recycled water supply.

Bellerive Area 3 Middle Estuary T N E W R E D

Residential

NEW COMMUNITY SURVEY RESULTS Sandy Sewage Howrah Factory treatment Bay plant A telephone survey of 200 residents across the greater Hobart Oil Wetlands and Catchment tanks area revealed that the Derwent estuary and its health are mudflats Recreational runoff fishing AY very important to the majority of people living here (83% of respondents) with many reporting that they thought that the

Stormwater health of the estuary had improved in the last five years (48%). TER CAUSEW outfalls Rowing

SMAN BRIDGE People use the estuary regularly for swimming (31%), boating/ Boating TA Sandy Bay BRIDGE WA rowing/sailing (31%) and fishing (29%). Walking beside the

Fresh INPUTS Exchange with (outfall from Tranmere water Oil lower estuary estuary was by far the most popular activity (69%). Compared mixing • sediment Selfs Point) • litter Plankton Underwater with a similar survey in 2007 there was a large increase in the Salt water • nutrients and natural sewage and • oil bacteria industrial • heavy metals outfalls physical activity associated with the estuary. What were the major • faecal bacteria Seawater environmental concerns for the Derwent estuary? The survey Rokeby Seagrass Shellfish and bottom dwelling water Marine pests Area results indicated that people in greater Hobart are most concerned organisms cycling Sludge and 4 Rokeby organic rich Heavy metal 3 about industry, litter, sewage and stormwater pollution. These sediment sediments deposits • nutrients 2 1 findings will inform the DEP’s communication efforts. See the • organic matter Microscopic • heavy metals sediment algae and executive summary on the DEP website for details. Taroona natural bacteria Lauderdale

Taroona Area 2 Lower Estuary

Garden waste, fertilizers, sediment Sewage Roads, land clearing, deforestation, treatment NO Beach sediment loss plant SWIMMING Kingston Stormwater drain Oil Swimming Oil

Stormwater outfalls Recreational

SMAN BRIDGE Ballast & commercial Oil Ralphs Bay

TA water Boating fishing

Mid estuary INPUTS exchange Plankton • sediment Underwater Oceanic Blackmans and natural • litter sewage exchange bacteria • nutrients outfalls • oil Bay • heavy metals Seagrass Kelp and Endangered • faecal bacteria other species seaweed Opossum Microscopic sediment algae and Marine pests Area natural bacteria Shellfish and water 4 Bay bottom dwelling 3 cycling organisms Heavy metal Rocky reef deposits sediment habitat 2 1 • nutrients Blackmans Bay • organic matter • heavy metals

Area 1 Ralphs Bay

WATER QUALITY MONITORING SITES IN 2012 RALPHS NORTH Beach monitoring site (enterococci) Sewage Good water quality treatment plant Catchment runoff Intermediate water quality Septic Tip site runoff Wetlands and BAY Poor water quality saltmarsWESTh Oil Ambient moitoring site (temperature, salinity, pH, Tinderbox N dissolved oxygen, nutrients, chlorophyll a, metals)

Recreational BAY 04 Stormwater fishing SEWAGE TREATMENT PLANT DISCHARGES IN 2012 Sailboarding outfall kilometres South < 2500 kL/d INPUTS Mudflats Arm 2500 - 5000 kL/d • sediment Plankton • litter and natural Exchange Microscopic sediment algae > 5000 kL/d • nutrients bacteria with and natural bacteria • oil estuary • heavy metals Shellfish and bottom • faecal bacteria dwelling organisms INDUSTRIAL DISCHARGES IN 2012 Area Heavy metal deposits 4 > 50 000 kL/d water 3 cycling Marine pests sediment 2 1 Iron Pot • nutrients • organic matter • heavy metals Betsey Island www.tasmap.tas.gov.au 10839BL