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This background section has common content with Water Quality in Tasmanian Estuaries, however, this section focuses in particular on the sources of pollutants. Unless otherwise stated, the following information is based on an estuarine water quality review prepared by DPIWE (Dowson 2002) for the SoE Report. This updates a similar report prepared for the last SoE Report by DPIWE in 1996. The majority of Tasmanians live within an estuarine catchment, with 84% living within the catchment area and 67% living in the coastal zone. This puts considerable stress on estuarine ecosystems through wastewater and industry discharges, and urban and rural run-off. Pollutants enter an estuary from a variety of sources, which can be divided into two categories, diffuse and point sources. Diffuse source pollution is difficult to measure, however it is probably the chief cause of water quality degradation in terms of organic matter, suspended solids, nutrients and chemical contaminants. Diffuse sources include run-off from urban, agricultural and forestry land, mine sites, landfill and other contaminated sites. Point sources are discharged at a single site from a single source. The scale and effect of point source discharges vary considerably, but large discharges can have marked local impacts and are often the most visible forms of pollution. Point source discharges to Tasmania's estuaries include: Discharges into estuaries can cause a number of adverse affects on the estuarine environment, aquatic organisms and human health. Discharges can lead to poor water quality, stained shorelines, unpleasant odours and colourations, health risks to humans, mutations and mortality in aquatic organisms, loss of recreational value, and the accumulation of toxins in the food chain. Edgar et al. (1999) identifies nine major threats to the ecosystem health of Tasmanian estuaries of which five are caused by discharges to estuaries. These include: Human impacts are only minor on the majority of the Tasmanian estuaries with 68% (61 of 90 estuarine catchment areas) being classified as pristine to low-impact on a naturalness index basis (Edgar et al. 1999). Twenty-four of the estuaries are classified as pristine, 20 as natural and 17 as low impact. Most estuaries are relatively healthy with indicator levels in the low to medium range (Murphy et al. 2003). However, many of the estuaries on the north coast (Boags bioregion) are degraded with relatively high turbidity and nutrient levels (Murphy et al. 2003). The remaining 29 estuaries are classified as moderate (21), high (7) and severe (1) impact (Edgar et al. 1999). In the north of the State, the Tamar River forms the west boundary of the Bell Bay heavy industrial zone, home to Comalco Aluminium, TEMCO and other industries. On the west coast, the Savage River and the King River are associated with mining industries in the Queenstown area. In southern Tasmania, the Derwent Estuary is associated with the Pasminco Hobart zinc smelter at Risdon, and the Norske Skog paper mill at Boyer. A number of Tasmania's heavy industrial facilities are located on the coast. Associated Pulp and Paper Mills (APPM) operates paper mills on the east coast at Triabunna, and on the north-west coast at Burnie and Wesley Vale. The Port Latta heavy industrial site is home to the Australian Bulk Minerals plant, with planning provision now being made for additional industries to be established in the future. Assessing and measuring the current situation The Derwent Estuary Urban effluent in the form of sewage, stormwater, commercial effluent and wastewater from heavy industry has been discharged into the Derwent estuary for more than 175 years. Although there have been significant improvements in the treatment of sewage and industrial wastes over the past decade, the estuary remains significantly degraded. Major problems caused by discharges into the Derwent estuary include: During 2001, point source discharges included 10 sewage treatment plants and two large industries (Norske Skog paper mill and Pasminco Hobart zinc smelter). Diffuse sources include urban run-off, run-off from tips and contaminated sites, inputs from the Derwent and Jordan River catchment areas and wastes associated with shipping, ports and marinas. A review of the various sources discharged to the Derwent in 2001 indicated that: According to the National Pollutant Inventory (National Pollutant Inventory 2003) the Macquarie Point WWTP discharged the most total nitrogen (TN) and total phosphorus (TP), releasing 120 and 27 tonnes respectively into the Derwent estuary during 2001-02. The Prince of Wales Bay WWTP, and Rosny and Blackmans Bay STPs also discharged significant amounts of TN and TP into the Derwent in this period. Pasminco discharged around 3,100 tonnes of sulphuric acid and 30 tonnes of fluoride and Norske Skog around 84 tonnes of TN in the same period (National Pollutant Inventory 2003). Trends since 1996 indicate a decrease in many of the indicators, but there has been a slight increase in nutrient loads discharged into the estuary. Records show a sharp decrease in faecal bacterial loads (>90%) and heavy metal loads (>50%) and a decrease in total suspended solids (TSS) (17%). An increase has occurred in discharged dissolved inorganic nitrogen (DIN) (8%), TP (17%) and biochemical oxygen demand (BOD) (15%) (Dowson 2002). Management Responses Significant changes in discharged pollutant loads have occurred as a result of better management and treatment practices and processing changes. Pasminco has decreased heavy metal loads through recent management actions and structural changes. Pasminco has constructed an effluent treatment plant to reduce wastes and wetlands to treat onsite stormwater. They have also constructed an innovative deep horizontal extraction well to intercept polluted groundwater before reaching the Derwent estuary. Long-term data sets for heavy metals suggest significant decreases in water column concentrations of zinc, cadmium and other metals over the past thirty years, but zinc levels in mid-estuary sites are still above recommended standards. Norske Skog paper mill has reduced discharged pollutant loads through structural and process changes. The mill has reduced the discharge of TSS (38%), resin acids (22%) and BOD (5%) as well as reducing the toxicity of effluent. An increase has occurred in the discharge of nutrient loads from STPs, however two have initiated secondary treatment processes (Selfs Point and Rokeby). Another two STPs (Brighton and Bridgewater) have ceased discharges to the Derwent under normal operations and commenced a full effluent reuse program. Brighton Council is also capturing and reusing some of its stormwater. The water is assisting in the economic viability of 1000ha of farmland used for growing vegetable seeds, poppies, fodder crops and other specialist products (DPIWE 2000). Some other significant management actions initiated or completed over the last 5 years include: The DEP has been highly successful in incorporating a wide range of stakeholders to build a common understanding, vision and management framework, and implementation of the program has occurred through formal partnership agreements and practical actions. Key aspects of the DEP Environmental Management Plan include: In 2000 the State Government, six local councils and three industrial/commercial partners (Norske Skog paper mills, Pasminco Hobart Smelter and Hobart Water) signed the Derwent Estuary Management Agreement. The agreement requires the coordination of independent monitoring to provide better information on the state of the estuary, and to report annually on environmental conditions and trends in the Derwent. Tamar River The major environmental concerns in the Tamar estuary are contaminations caused by sediments and biota containing pathogens, hydrocarbons, heavy metals and other pollutants such as fluoride, cyanide and phenols. Discharges from point sources include ten STPs (six located in the upper estuary) and several industrial sources in the lower estuary. Major industries in the lower estuary include two woodchip mills at Long Reach (Gunns Ltd), gold mining at Beaconsfield, and two metal processing industries at Bell Bay (Tasmanian Electro Metallurgical Company (TEMCO) and Comalco Aluminium (Bell Bay) Limited). According to the NPI (2003), the Beaconsfield Gold Mine discharged around 210 tonnes of chlorine into the Tamar estuary in 2001-02. Diffuse sources include sediment, organic and nutrient loads from the North Esk and South Esk Rivers (derived primarily from agricultural run-off from crop lands and pastures), heavy metals leaching from several closed mines in the South Esk River catchment, and urban run-off. Other potential diffuse sources include atmospheric fallout and pollutants leached from contaminated sediments within or adjacent to the estuary. The Launceston sewage system is thought to be a major contributor, especially during wet weather due to the sewage/stormwater combined system. Illegal connections feed rainwater into the sewers instead of the stormwater drains. High flows during heavy rainfall mean that STPs can become overloaded and end up discharging raw sewage. Past water contamination caused by pathogens has been derived from sewage and abattoir activities, however all STPs have now been upgraded to include secondary treatment with disinfection and the abattoir has since closed. Contamination by pathogens is indicated by elevated levels of faecal coliforms, and is caused by sewage/stormwater system and pumping station overflows, and agricultural run-off after heavy rainfall events. Nutrient inputs from STPs and agricultural and urban run-off are potentially significant, but the Tamar is not presently known to experience algal blooms. The Newnham WWTP discharges the highest quantities of nutrients with 55 tonnes of TN, 17 tonnes of TP and 35 tonnes of ammonia being recorded by the NPI in 2001-02 (Dowson 2002). The levels of TN and TP recorded over the last few years in the upper estuary are above the default trigger values set by the ANZECC 2000 guidelines, although there has been a significant drop in the bacterial levels since 1994. Historic activities have left their mark in the Tamar through the contamination of estuarine sediments and groundwater. Heavy metals, particularly zinc, cadmium, lead and copper have been recorded at elevated levels in several areas, notably the upper estuary around Launceston and the lower estuary around Deceitful Cove and Middle Arm. Historic point sources such as the South Esk catchment and diffuse sources such as run-off from contaminated sites forms the bulk of this contamination. Huon River To date, sewage and industrial discharges have not adversely affected the long-term water quality of the estuary. This is supported by the healthy shellfish industry of the estuary. Recent surveys undertaken as part of the Huon Estuary Study 2000 indicated that trace metal levels in the sediments and water were below the national guidelines, except for copper, cadmium, lead and zinc in Hospital Bay and Port Cygnet. Discharge point sources include STPs, tip leachates, and agricultural activities such as dairies. Diffuse sources are generally derived from natural sources (the weathering of rocks, land run-off, soil leaching, and plant material breakdown) and human activities (agricultural and urban stormwater run-off). Other inputs include marine farms and forestry run-off. Forestry and agricultural run-off can transport topsoil, fertilisers, soil conditioners and other chemicals into the estuary. Elements such as copper and iron occur naturally in high concentrations in some of the streams entering the estuary. Three STPS discharge effluent into the estuary (Port Cygnet, Geeveston and Ranelagh), however all now perform secondary treatment with disinfection prior to release. The town of Franklin previously discharged untreated wastewater into the estuary, but it has since been connected to the Ranelagh WWTP. In general, all three STPs have been found to be discharging BOD, suspended solids and thermotolerant coliforms in excess of their permit limits. Port Cygnet has complied with the performance requirements since late 1998 on the majority of occasions, Geeveston has had several non-compliance occasions, while Ranelagh has very rarely complied with the required levels for thermotolerant coliforms. Studies completed by Wotherspoon et al. (1994) estimated the current rates of nutrient inputs into the river and compared them with estimates from before European settlement. No significant change in nitrogen input has occurred, but phosphorus inputs have trebled. It is thought that elevated phosphorus levels are caused by the salmon aquaculture industry (about 70%), but the increase is localised in the form of faeces under the sea cages. Slow population growth and marginal changes in land use, improved stormwater management practices and upgrades to sewage systems mean that future municipal and agricultural waste inputs are unlikely to pose a threat to water quality in the Huon estuary. Macquarie Harbour Macquarie Harbour is Tasmania's largest and one of Australia's largest estuarine systems. The catchment is sparsely populated with the two major centres of Strahan and Queenstown. National Parks and conservation areas, tourism, mining, forestry, port operations, aquaculture and hydro-electric power generation are the major uses of the catchment. The two major inputs into the harbour are the Gordon and King Rivers. The water quality of the Gordon River is of a high standard compared to the King River. With the exception of iron and manganese, there is no measurable input of trace metals from the Gordon River. The iron and manganese levels are typical of the water body type and are not regarded as toxic. The King River is highly impacted by the inflow of acid mine drainage from the Mt Lyell copper mine in Queenstown. Mine drainage and run-off from waste rock discharges acidic, metal rich water into the Queen River, which flows into the King River and eventually into the harbour. Tailings from the Mt Lyell mine are no longer discharged into the Queen River, however acid water laden with heavy metals still drain into the King River system. Since the mine closed in 1994, the amount of sediment reaching the harbour has reduced, but recorded concentrations of copper at the mouth of the King River have been as high as 2000ppb. The ANZECC guidelines recommend a maximum copper concentration of 1.3ppb in marine waters. In regions where 100-200ppb was normal before 1994, concentrations have reached 400-500ppb. The situation corresponds with the termination of mine tailings discharges into the Queen River. The tailings had previously acted as a neutralising agent for the acid water and reduced the precipitation of heavy metals. The acid water also remobilises the heavy metals previously deposited in the sediments on the river banks and the delta. Virtually all water samples taken from harbour exceed the ANZECC 2000 water quality guidelines for copper in marine ecosystems. The northern harbour has been affected by heavy metals discharged from the Mt Lyell copper mine for over 100 years, and this continues to be the primary source of copper, aluminium, zinc and other metals entering the harbour. Copper concentrations in the surface and middle depths at station 14 have shown a gradual decline since 1995, but a peak occurred in July-September 2001. Near record rainfall in June and further rain in the following months caused high flows containing heavy metals derived from mine drainage. Unless effective remedial action is taken, acid and heavy metal drainage will continue to be discharged from Mt Lyell for many hundreds of years. There are also two level 2 STPs that discharge into Macquarie Harbour at Strahan and Queenstown. The Strahan plant discharges into Macquarie Harbour while the Queenstown plant discharges into the Queen River. Both plants do not comply with microbiological discharge limits and on many occasions the Strahan STP discharges excessive BOD and suspended solids. With the present degraded status of the Queen River, upgrading the Queenstown plant is not considered a high priority. Pollution from marine farming and activities in the Strahan area have yet to be quantified, however any such pollution is likely to add to the stresses of the northern harbour. North-West Coast Estuaries The north west coast marine environments have a history of contamination from municipal and industrial wastewater discharges, spills from pump stations and wharves, urban stormwater run-off and heavy metal laden run-off from mining areas. Rivers and streams in the north west are also naturally high in minerals, derived from weathered rock and soils. Major sources of pollutant discharges originate from the waste water treatment plant WWTPs and industries associated with the major centres of Burnie, Devonport, Ulverstone, Wynyard, Somerset and Smithton. The Pardoe (Devonport), Pelican Point (Smithton) and Ulverstone WWTPs discharged the highest levels of TN and ammonia in 2001-02 (National Pollutant Inventory 2003). Major industries, particularly mining, discharge large amounts of heavy metals as point and diffuse sources. Goldamere P/L runs an iron ore pelletising plant at Port Latta and an open cut magnetite mine at Savage River. The Savage River mine discharges large quantities of heavy metals into the Savage River, which eventually flow into the Pieman River on the west coast. Major pollutants include manganese (870 tonnes in 2001-02), cobalt (11 tonnes in 2001-02), copper, fluoride, arsenic, nickel, zinc, lead, mercury, chromium and cadmium. The mine also discharged around 95 tonnes of TN in the year 2001-02. Major pollutants from the pelletising plant at Port Latta include fluoride (36 tonnes in 2001-02), arsenic, nickel and chromium (National Pollutant Inventory 2003). Burnie Coastal Waters Emu Bay, off the coast of Burnie, is classified as moderately impacted on an estuarine catchment area basis and severely impacted on an estuarine drainage area basis (Edgar et al., 1999). Historically, the waters off Burnie have been the discharge point for three large industries: Other inputs include two WWTPs (Cooee and Round Hill), BP Australia Burnie Terminal and Mooreville Road Landfill. The Round Hill WWTP discharges the most TN and ammonia, and BP Australia discharges low amounts of petroleum hydrocarbons. According to the National Pollutant Inventory (NPI) (2003), Mooreville Road Landfill releases small amounts of a number of pollutants mainly through run-off and soil leaching. The iron-rich solution discharged from the Tioxide factory has significantly reduced to leachate and drainage from the site since its closure in 1996. In 1994 and 1996 marine surveys detected elevated levels of mercury in the vicinity of the Tioxide outfall, but further surveys in 1998 found no detectable mercury. In 1997 a 1300m long ocean outfall was constructed to help reduce the effect of the paper mill effluent on the near shore water quality. In October 1998, Amcor shut down part of the Australian Paper Mill. This has significantly increased the quality and reduced the quantity of wastewater emitted by the operation. From 2000, the mill has continually improved its operation and management in accordance with accreditation within ISO 9001 (Quality Control) and 14001 (Environmental Management Systems). Since the closure of Tioxide Australia and part of the Australian Paper Burnie mill the marine environment is returning to background status. Mill effluent no longer influences the water quality of the shoreline, and water clarity has improved substantially since this time with surveys recording indicator levels that are typical of coastal waters. The Burnie Port activities, municipal wastewater and stormwater, and inputs from Emu River and Romaine Creek still potentially affect coastal water quality. Mersey River The Mersey Estuary is classified as lowly impacted on an estuarine catchment basis and severely impacted on an estuarine drainage area basis (Edgar et al., 1999). General catchment and stormwater impacts on the Mersey Estuary are high, both from upstream and in the local catchment. A number of creeks that flow into the Mersey Estuary are degraded, namely the Kings, Horsehead, Cockers and Figure of Eight Creeks. The Latrobe STP has caused water quality problems in the past, however effluent is now being diverted to the Devonport ocean outfall. The NPI (2003) indicates that the Pardoe WWTP introduced the most TN (170 tonnes), TP (34 tonnes) and ammonia (86 tonnes) into the estuary in 2001-02. |
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Industry Responses Tasmania's heavy industries have great socio-economic value to the State, providing direct employment to over 5,000 people, indirect employment for numerous other businesses, and producing raw material for the manufacturing sector. However, environmental regulations and community expectations are such that these industries must now operate without compromising the quality of the State's inland and coastal waters. These waters support recreational activities such as sailing and swimming, support commercial activities such as fishing and aquaculture, are home to many species with conservation significance, and are a major tourist attraction. Inland waters also provide drinking water for communities, and irrigation for agriculture, and the importance of conserving and managing these resources is increasing as climate change concerns grow. Waste water treatment systems enable industrial facilities to continue operating while respecting the need to conserve and manage our water resources. Without appropriate waste water treatment systems, most heavy industrial facilities would be associated with water quality standard non-compliance issues, and would not be permitted to operate in Tasmania. The adverse impact of industries operating without waste water treatment systems has been documented in numerous case studies around the world, and problems can sometimes persist long after the source of the pollution is removed. Tasmanian heavy industries are licensed by the State Government, and operate according to regularly reviewed environmental management plans, which address waste water emissions, and whose commitments are usually incorporated into the facility's operating permit conditions. In addition, most heavy industries have established environmental management systems based on the ISO 14001 standard, and underpinned by the philosophies of self-regulation and continual improvement. Most Tasmanian heavy industries can point to a series of waste water treatment initiatives since the 1980s, and the investment in these is providing on-going environmental benefits. The industry-specific nature of waste water streams means that a wide variety of treatment systems have been devised. Examples of waste water treatment systems built and commissioned over the past decade or so, are shown in the following photographs.
Adopting cleaner production methods has solved water pollution problems for some industries. The best known example of this is the Pasminco Hobart smelter's process changes since the last SoE Report. These changes enabled the smelter to cease the production of jarosite, instead producing a product that is shipped to Pasminco's lead smelter at Port Pirie in South Australia, where it is processed into a vitreous slag that is acceptable for land disposal. This change of process allowed Pasminco Hobart to cease ocean dumping of jarosite waste, in compliance with the London Sea Dumping Convention. In addition to waste water treatment, other approaches by heavy industry to mitigating water pollution problems include engineering groundwater intercept systems, covering stockpiles to avoid leachate production, and improving site stormwater controls. A suite of studies was carried out in the 1990s as a major cooperative venture between the State and Commonwealth governments, and recommended a remediation strategy that aims to undo the damage of past mining, while preserving the benefits of ongoing mining. For example, the Mount Lyell Remediation Final Report (1997) is available from the State Government. Reporting on industry emissions through the National Pollutant Inventory is mandatory in Tasmania (under Section 43 of the Environmental Management and Pollution Control Act 1994), and from July 2001 reporting against 90 substances has been required (an increase from the original 36 substances) (DPIWE 2002). The Derwent Estuary Monitoring Agreement was signed in August 2000 by the state government, six local councils and three industrial/commercial partners (Norske Skog Paper Mills, Pasminco Hobart Smelter and Hobart Water). The signatories agreed to coordinate their independent monitoring programs to provide better information on the estuary as a whole, and to report annually on environmental conditions and trends in the Derwent. The State of the Derwent Year 2000 Report Card (DPIWE 2000) was the first annual report for this estuary monitoring process, and provided a summary of monitoring data and an update of conditions for the year 2000. Much study work has been carried out over the past decade to assess the environmental impact of waste water discharges from Tasmania's heavy industry. The work has been aided by improved procedures for sampling and chemical analysis that have developed to be able to detect trace chemical components at concentrations significantly lower than was possible in the 1980s. In addition, a major step forward in our ability to assess water quality has been the emergence of computer dispersion models as credible tools for predicting how contaminants in waste water disperse into the receiving water. There has been much progress over the past decade towards agreement on the process of setting water quality objectives, and on best-practice industrial waste water treatment expectations. In some ways, the challenge for industry and regulators alike has been greater than for air pollution control, requiring catchment-by-catchment consideration of aquatic ecosystems, water usage, and water quality objectives. The work to engineer effective waste water treatment systems has required much study to understand the chemistry and flow characteristics of industrial waste water streams, and to understand the transport dynamics of residual contaminants discharged to a receiving water. This ongoing process defines the main direction of work over the coming years, as industries direct their resources to continuing to monitor effluent dispersal and receiving water quality, and to working with government and local communities to refine water quality objectives and waste water treatment systems if need be. Future assessment and monitoring of Tasmania's estuaries requires clearly defined sampling sites and sampling protocols to provide baseline data for meaningful and long-term comparisons. In 1999-2000, the first detailed assessment of Tasmanian estuaries was undertaken to monitor the water quality in 22 estuaries (Murphy and Crawford 2002). The assessment was aimed at providing baseline water quality data, determining water indicator levels and proposing appropriate monitoring protocols for Tasmania's estuaries. Comparative assessments should be conducted at least every five years and should correspond with the SoE Reporting cycle. Murphy and Crawford (2002) suggest that acquiring funding for broad scale and long-term estuarine water quality monitoring is likely to be the greatest challenge. Tasmania Together and the RMPS Relevant Tasmania Together goals and standards for 'Coastal, Estuarine and Marine' are listed in the linked file. The Tasmania Together Progress Board reported on progress toward targets for benchmarks set (Tasmania Together Progress Board 2003). Indicators, targets and baseline data are available in the latest Progress Report June 2003. Further information, including progress report updates, is available from Tasmania Together. Involvement of the community, and the fair and orderly use of resources are also fundamental principles of the RMPS. The RMPS objectives have been developed to advance the principles of sustainable development.
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