Background

Implications

Regional aspects

Assessing and measuring the current situation

Management responses

Future directions

Related issues

Related case studies

Background

The release of pollutants into the environment can kill organisms outright, change the biogeochemical conditions and processes occurring within a system and result in systemic changes that degrade habitats and make ecological processes dysfunctional. Biodiversity associated with sites intensively used by humans may be most at risk, although the non-point based effects of pollution on biodiversity such as downstream water pollution and downwind air pollution can be significant (Australian State of Environment Committee 2001).

Urban stormwater may contain high levels of contaminants such as faecal bacteria, nutrients, chromium, cadmium, lead, nickel, hydrocarbons and chlorinated hydrocarbons. In rural areas, irrigation run-off from farming activities may sometimes contain insecticides, fertilisers and herbicides that have been applied to crops. This run-off may affect aquatic and marine organisms living in the catchment and its associated estuaries and in-shore marine ecosystems (Australian State of Environment Committee 2001).

Chemicals from pesticides can accumulate in the food chain, particularly in the higher order animals, and can damage non-target populations if applied carelessly. As with pesticides, heavy metals can accumulate in the food chain, especially in the aquatic environment. This can cause health problems for fish and other animals higher in the food chain (including humans). Heavy metals in the Derwent estuary have accumulated in shellfish to levels where the shellfish are unsafe for human consumption.

In the past,atmospheric pollution and acid run off killed mountain vegetation around Queenstown and affected aquatic ecosystems (e.g. 'dead' sections of river systems such as the Queen and King Rivers-see King River Case Study). These examples indicate how pollutants can act synergistically to cause unpredictable long-term effects on biodiversity. These effects are compounded by the cyclical nature of ecosystem processes, which disperse pollutants widely from their sources and may affect biodiversity at considerable distances in a variety of surprising ways.

Oil and fuel spills, such as those from the Iron Baron in 1995, can seriously damage marine biodiversity (see case study on p. 7.36 in the first State of the Environment Report 1997 - Coastal, Estuarine and Marine). Most visibly harmed are those animals that spend time on the surface of the water, such as penguins and cormorants. However, other organisms such as seaweeds and the molluscs and crustaceans of the shoreline can also be devastated by such spills. Similarly, low levels of oil pollution, such as those around large marinas, can harm marine life over longer time periods.

Another form of water pollution is nutrient enrichment. Known as eutrophication, extra nutrients allow some species to thrive and multiply, smothering other inhabitants of the water bodies. The algae in particular, flourish in such conditions. Dense 'blooms' can block out light, reduce water mixing, and at night when they are not photosynthesising, can place such a demand for oxygen in the water that other organisms such as fish are suffocated. There may also be releases of toxic chemicals.

Eutrophication is more likely to occur in summer, when the warmth combined with nutrients from sources such as sewage, fertiliser and detergents encourages excessive growth. In Tasmania, nutrients also accumulate around fish farms (see Marine Farming Issue Report).

In general, potential effects of pollutants on ecosystems include changes in the abundance of species, interruption to energy and nutrient flows, modification of habitats, reduction in soil, water and air quality, and changes to the stability and resilience of ecosystems.

Implications

Pollution and eutrophication can range from the minor where it is more of an aesthetic nuisance, to areas significantly affected where the health of organisms living in the area, and those relying on the area (including humans) can be seriously affected.

Regional aspects

While it is the waterways that are most commonly referred to, there are many terrestrial areas similarly affected. Atmospheric pollution can also have a significant affect. Hence pollution and eutrophication is an issue throughout the State.

Assessing and measuring the current situation

The SoE Report recognises that there is some new information available on the effects of pollutants on Tasmania's biodiversity. However, it was not possible to present a full discussion of this information in this second report within the time available. A limited discussion of some example assessments that have been conducted and relevant indicators that are included in other issue reports, is provided below.

Water Pollution

In Tasmania, measured exceedences of the ANZECC water quality guidelines (ANZECC 2000) for a suite of bacterial and chemical water quality parameters provide information relating to various environmental values, including the protection of aquatic ecosystems. Water quality guidelines are concentrations of a particular water quality variable above which the risk of adverse biological effect is considered unacceptable. The percentage of exceedences of water quality guidelines in Tasmania are presented in indicators for inland waters and coasts and estuaries.

Pollution in the form of nutrient enrichment can lead to eutrophication and, for example, increased levels of algae or algal blooms, which can be harmful to the biodiversity of the aquatic system. The concentration of the photosynthetic pigment chlorophyll a (referred to as chlorophyll) in marine waters is a proven indicator of the biomass of microscopic plants such as unicellular algae. Increases in the annual median concentrations of chlorophyll in individual waterbodies may be related to changes in nutrients, and to increasing eutrophication (see Chlorophyll Concentrations In Tasmanian Estuaries Indicator).

The ANZECC (2000) default trigger levels for estuarine water quality contain no Tasmanian nutrient or chlorophyll data. Therefore, draft indicator levels of nitrogen (key nutrient) and chlorophyll in Tasmanian estuaries, referenced against the baseline values from a Tasmanian Aquaculture and Fisheries Institute study (Murphy et al. 2003), have been used as surrogates in the Water Nutrients (Nitrogen) In Tasmanian Estuaries and Chlorophyll Concentrations In Tasmanian Estuaries Indicators. Not only can high levels of nitrogen lead to eutrophication, but in less severe circumstances, excess levels of nitrogen cause initially subtle but eventually chronic changes to marine ecosystem structure.

The frequency of algal blooms is usually related to land based sources of nutrients. Data are collected by Department of Health and Human Services (DHHS) as part of the Tasmanian Shellfish Quality Assurance Programme, which assesses shell fish growing areas for public health risk. Therefore, data collection is limited to estuaries with marine farming taking place. However, investigation of the data available in Tasmania indicate high variability between the different sites both over space and time. Because of difficulties in clearly defining a harmful algal bloom (e.g. number of cells defining a bloom varies between species-see Algal Blooms In Estuarine and Marine Environments Indicator Report), it is impossible to say if such variability is a function of natural fluctuations in algal levels or if variations are indicative of significant ecosystem imbalance due the impact of human activities.

Atmospheric Pollution

Tasmania's biodiversity has been severely impacted in the past through atmospheric pollution (e.g. pollution from the past smelting activities at Queenstown). There may be some atmospheric pollutants (e.g. air toxics) that are affecting the State's biodiversity in the present. Emissions of air pollutants are being measured through the National Pollution Inventory (NPI), including emissions from facilities, diffuse pollution sources, and emissions from Hobart and Launceston airsheds (see Emission of Air Pollutants). The potential environmental effects (e.g. to fauna) of various pollutants is reported on by the NPI. For example, links to NPI background information for five key air toxics including their potential environmental toxicity to flora and fauna are listed below:

• Benzene
• Polycyclic aromatic hydrocarbons
• Formaldehyde
• Toluene
• Xylene

The enhanced greenhouse effect is the outcome of pollution at global scales through the release of greenhouse gases. Climate change has potential consequences for many native species in Tasmania.

For further information on the causes of pollution refer to the issues relating to pollution listed in the Atmosphere, Land, Inland Waters and Wetlands, Coastal, Estuarine and Marine and Settlements Chapters.

Management responses

Pollutants released into Tasmania's inland waters and wetlands; terrestrial or coastal, estuarine and marine environments; or into the atmosphere are a threat to the State's biodiversity. There have been various management responses to this issue, many of which are discussed in the Atmosphere, Inland Waters and Wetlands, and Coastal, Estuarine and Marine Chapters, while some examples are presented below.

Inland waters and wetlands pollution

• The State Policy on Water Quality Management 1997 encapsulates the water quality management approach recommended by the National Water Quality Management Strategy (NWQMS). Two of the key objectives of this policy include:
   
• Ensure that pollution discharged from point sources (such as industrial or sewage treatment plant discharges) and diffuse source (such as runoff from urban areas, farms, forest harvesting, roads etc) does not prejudice the achievement of water quality objectives, and that pollutants discharged into waterways are reduced as far as possible by the use of best practice environmental management;
• Ensure that efficient and effective water quality monitoring programs are carried out and that the responsibility for monitoring is shared by those who use and benefit from the resource, including polluters, who should bear an appropriate share of the costs arising from their activities, water resource managers and the community.
• A Draft Tasmanian Water Quality Monitoring Strategy has been developed as one of the responses to the State Policy on Water Quality Management 1997. The Strategy allows for the more efficient integration of water quality monitoring and data management across the State. Water quality data is essential for water resource management, e.g. to assess land use effects and monitor improvements in the land and water management policies and practices.
   
• A Draft State Stormwater Strategy has been developed to provide a consistent Statewide approach to stormwater management planning and the adoption of management measures by local councils, such as:
   
• Code of Practice for control of runoff from land development sites;
• 'at source' pollution control strategies developed;
• stormwater reuse strategies developed for urban areas where annual rainfall is less than 700 mm or otherwise under the stormwater management planning process;
• sewage/stormwater cross connection management programs developed; and
• site remediation programs developed for areas of urban bushland that currently receive stormwater discharge.
• The Managing Dairy Farm Effluent in Tasmania Code of Practice, August 1997.
   
• The development of Emission Limit Guidelines for sewage treatment plants, fruit and vegetable processing activities, meat premises and pet food works, and intensive animal husbandry activities.
   
• RiverWorks Tasmania is a major program launched in 1997 with the aim of reducing pollution in Tasmanian rivers, concentrating on wastewater treatment plant discharges.
   

Coastal, esturaine and marine pollution

• On 16 April 2003 the State Coastal Policy Validation Act 2003 came into effect. This Act replaces the former definition of the Coastal Zone in the State Coastal Policy 1996 and reinstates the Policy. The Act also validates all previous decisions made under the Policy.
   
• There is an established ongoing monitoring program in place for water quality testing in shellfish growing areas. The Tasmanian Shellfish Quality Assurance Programme (TSQAP) was set up in the mid-1980s to evaluate and classify all commercial shellfish farming areas in the State by way of routine bacteriological, chemical and biotoxin monitoring.
   
• Research has been conducted on the effects of organic enrichment of the sea bed due the deposition of faeces and waste food from salmon cages (TAFI 2000).
   

Atmospheric pollution

• According to Tasmania's Air NEPM monitoring plan (DPIWE 2000), daily monitoring of particles (as PM10) will be conducted in both Hobart and Launceston. The National Environment Protection Council is also currently developing a variation to the NEPM on Ambient Air Quality to extend it's coverage to PM2.5 (particulate matter 2.5 micrometres or less in size).
   
• The National Pollutant Inventory (NPI) is providing good information on the scale of emissions in Tasmania. The NPI requires reporting from industrial facilities that trip certain thresholds of pollutant emission to DPIWE. Reporting has been formally made mandatory in Tasmania as from 2002 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 Draft Environment Protection Policy (Air Quality) and Regulatory Impact Statement (DPIWE 2001), which is expected to be in operation by mid 2003, requires point sources of air emissions to be managed in accordance with the following principles:
   
• accepted modern technology should be applied to reduce emissions to the greatest extent practicable;
• a reserve capacity should be maintained for airsheds, so that future additional emission sources will not prejudice compliance with the Air NEPM standards, and;
• emissions of a pollutant should not cause specified ambient criteria to be exceeded.
• A draft Ambient Air Toxics NEPM and impact statement has been released (May 2003) for public comment. An Ambient Air Toxics Discussion Paper is also available. Air toxics are gaseous, aerosol or particulate pollutants which are present in the air in low concentrations with characteristics such as toxicity or persistence so as to be a hazard to human, plant or animal life.
   

Future directions

Indicators that would be useful to report on in the future include:

• Bio-accumulation of pollutants (the levels of major contaminants in biological accumulators in the estuaries, lagoons, bays and continental shelves of the mainland and offshore islands);
   
• Control over the impacts of pollution on biological diversity (amount of funding for, and number of, research programs into the effects of pollution on biological diversity and how to alleviate them, and number of State and local laws or regulations that explicitly deal with the impacts of pollution on biological diversity);
   
• Chemical residues (chemical residues in aquatic biota or foodstuffs);
   
• Pesticide exposure (estimated contamination by pesticides in the riverine environment, per drainage division); and
   
• Pollution point sources (inventory of licensed point sources of pollution, as measured by number of point sources by source type per drainage division).
   

Tasmania Together and the RMPS

Relevant Tasmania Together goals and standards for 'Biodiversity' 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.

Related issues

Related case studies