Inland Waters Theme Report

Australia State of the Environment Report 2001 (Theme Report)
Prepared by: Jonas Ball, Sinclair Knight Merz Pty Limited, Authors
Published by CSIRO on behalf of the Department of the Environment and Heritage, 2001
ISBN 0 643 06750 7

Water quality and sources of pollution (continued)

Groundwater pollution (continued)

Condition: The quality of groundwater resources

  • Contamination of groundwater by nitrates
  • Contamination of groundwater by pesticides
  • Other groundwater pollutants
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    Contamination of groundwater by nitrates

    Nitrate contamination of groundwater (indicated by >10 mg/L nitrate) in Australia is widespread and occurs over regional and local scales (LWRRDC 1999). In many areas, the concentration is greater than the recently revised Australian Drinking Water Guidelines (NHMRC /ARMCANZ 1996) level of 50 mg/L nitrate (as nitrate), resulting in groundwater that is unfit for drinking. In some of the more contaminated areas, the concentration is in excess of 100 mg/L (LWRRDC 1999).

    Figure 22 shows the distribution of bores across the nation, with nitrate levels greater than 10 mg/L. The map shows that nitrate concentrations above 10 mg/L (as nitrate) are widespread throughout each state and territory and are found both in undisturbed areas and those affected by human activities.

    Figure 22: Distribution of bores across Australia, with nitrate levels greater than 10 mg/L

     Distribution of bores across Australia, with nitrate levels greater than 10 mg/L

    Source: LWRRDC 1999.

    The most effective way of minimising nitrate loads to groundwater is to carefully manage the application of fertilisers for cropping or pasture (LWRRDC 1999). It should be noted that other sources of nitrate contamination are grazing and clearfelling (LWRRDC 1999), and that these are more difficult to manage. There is also potential to reduce nitrate pollution from point sources. Point-source pollution from manufacturing facilities, agricultural processors, landfills and sewage treatment plants can be managed and reduced through licensing and development approval.

    Contamination of groundwater by pesticides [IW Indicator 3.5]

    Systematic monitoring of pesticide contamination of groundwater in Australia is limited. Recent incidences of reported pesticide contamination of groundwater are listed in Table 26. In most affected areas, pesticides were detected in at least 20% of samples, indicating significant contamination.

    Table 26: Documented cases of (diffuse) pesticide contamination of groundwater in Australia
    State or territory Area Principal contaminant Percentage of groundwater samples contaminated
    Victoria Shepparton EastC Atrazine and Simazine 50
      Goulburn-Broken catchment:D
    Shepparton East
    Atrazine and Simazine
    Atrazine and Simazine
    Atrazine and Simazine
    Atrazine and Simazine
      ArdmonaF Dieldrin, Chlorpyriphos and Amitrol n/sA
      GirgarreF No pesticides above ANZECC criteria  
      Ky ValleyF No pesticides above ANZECC criteria  
    Western Australia Kwinana industrial area near PerthK Herbicides 2,4-D and 2,4,5-T n/s
    NSW Lower Namoi ValleyB Atrazine 4
      Murray-Riverina catchment:
    Berriquin Denimein areaD
    Atrazine and Simazine 16
      Liverpool PlainsE Atrazine
    Isolated detections of Simazine, Metolachlor, Trifluraline and Diuron
    Queensland Burdekin DeltaC Atrazine
    To a lesser extent the Atrazine Degradation
      Logan-Albert catchment (SE Qld)J No pesticides detected  
      Border Rivers catchment:
    Western and MacIntyre sectorsD
    Atrazine and Simazine 16
    South Australia PadthawayC Atrazine and Simazine
    To a lesser extent the DEA
      Piccadilly Valley, near AdelaideI Atrazine 5
      Lower south-east of SAG Dieldrin, Lindane, Chlorpyrifos and Alachlor 15
    Northern Territory Darwin rural regionH No pesticides detected  

    A n/s - not stated;B Jiwan and Gates, 1994;C Bauld, 1994;D Bauld et al. 1998;E Timms & Cooper 1998; F Wenig & Lawrence 1998;G Schmidt et al. 1996;H Radke et al. 1998;
    I Ivkovic et al. 1998;J Please et al. 1996;K Appleyard 1993.

    A 1996 review of pesticides in the Australian environment (Schofield & Simpson 1996) concluded that there were inadequate data on the quantities, locations and types of pesticides used, as well as knowledge gaps in the fate of pesticides in local environments.

    Other groundwater pollutants [IW Indicator 3.6]

    There is very little publicly available information on groundwater contamination for pollutants other than nitrates and pesticides. It is likely that groundwater contamination is considerably worse than reported below; however, most information is held by private companies or government organisations and is confidential.

    Municipal landfills are primarily located in urban areas throughout Australia. Most of the information on groundwater contamination from landfills is contained in private consultants' reports and for this reason, the extent of contamination from landfills is largely unknown. However, waste containment design practices in Australia are continuing to evolve, and with increasing regulatory control and greater scientific understanding and public awareness, landfill designs have improved and the potential for leachates to contaminate groundwater has markedly reduced.

    There are many other sources of groundwater contamination and these are listed in Table 30. Groundwater pollutants can take between 10 to 100 years or more to contaminate an aquifer and be detected. The time lag between contamination and its detection is a major issue for the management of groundwater, as often contamination may not be detected until long after the polluting land use has ceased.

    Table 27: Known occurrences or documented cases of point-source pesticide contamination of groundwater
    State or territory Area Source
    Victoria Gisbourne
    8 sites
    6 sites
    Cattle / sheep dips
    Western Australia Residential area of PerthA Effluent from pest control operators - Fenamiphos and Atrazine
      Kwinana industrial area near PerthB Effluent from an agrochemical manufacturing plant
    NSWC Mullumbimby
    Lismore: Goonellabah
    Lismore: Astenville and Newrybar
    Rozelle and Hopefield Siding
    Liverpool PlainsD
    Cattle / sheep dips
    Cattle / sheep dips
    Cattle / sheep dips
    Abandoned chemical drums
    ACT No known pesticide contaminated sites  
    QueenslandE Unknown  
    Northern TerritoryF Darwin Rural area Manufacturing - Aldrin spill
    Tasmania Exeter, Land II Manufacturing - Dieldrin spill

    A Davis & Appleyard 1996; B Appleyard 1993;C 1603 other cattle/sheep dip sites in NSW have been identified between 1991-92, however, the relationship to these groundwaters has not been assessed (Knight 1993);D Timms & Cooper 1998;E Queensland's 1500 cattle / sheep dip sites are thought to be contaminating soil only. Rarely have groundwater studies been undertaken (Knight 1993); F The Northern Territory is thought to have a number of cattle / sheep dip sites, however, documentation is lacking (Knight 1993).

    Source: Adapted from Knight 1993.

    Table 28: Known occurrences of hydrocarbon contamination of groundwater
    State or territory Area Source
    Victoria 9 sites
    2 sites in Melbourne - Geelong region
    1 site
    Industrial / manufacturing / storage facilities
    Fuel station
    Western Australia 8 sites, including 2 sites on the Swan Coastal PlainA Fuel stations
    NSW 5 sites, including Anna Bay, Botany and Matraville
    1 site
    Industrial / manufacturing / storage facilities
    ACT 3 sites Fuel stations
    Queensland 1 site in Cairns Fuel station
    South Australia 6 sites: Mt Gambier (2 sites), Bordertown, Jamestown, Fregon and Minlayton Fuel stations
    Northern Territory 1 site: Croker Island Fuel station
    Tasmania Several (number and locations unknown) Fuel stations

    A The two sites on the Swan Coastal Plain are documented in Davis et al. 1993.

    Source: Adapted from Knight 1993.

    Table 29: Known occurrences of gasworks site contamination of groundwaterA
    State or Territory Area
    Victoria Port Melbourne, West Melbourne, South Melbourne, Melbourne
    Echuca, Morwell, Heidelberg, Geelong North, Ballarat
    Western Australia East Perth
    2 sites unidentified
    NSW Newcastle and Mortlake
    Waverton, Little Manly Point, WoollstoncraftB
    Sydney (5 sites) and Armidale, Tamworth, Casino, Albury, Cootamundra, Goulburn, Lithgow, Bathurst and Orange.
    Queensland 6 sites (including 2 in Brisbane)

    A The 17 sites with some documented public record are a small fraction of the total number of gas works sites (>100).
    B Groundwater contamination is reported to be minimal at each of the three sites.

    Source: Adapted from Knight 1993.

    Table 30: Other point sources of contamination
    Activity Source / type of contamination
    Monitoring, exploration and production bores Potential for cross contamination of aquifers.
    Contaminants can be introduced into the groundwater during drilling of production bores.
    Improperly constructed bores, corroded bore casings and improperly abandoned bores.
    Injection bores Injection wells are used to discharge liquid wastes and other liquids into subsurface zones below the water table. Liquids that are injected include: hazardous wastes, brine from oil wells, agricultural and urban run-off, municipal sewerage, air-conditioning return water, heat pump return water, liquids used for enhanced oil recovery from oil fields, treated water intended for artificial aquifer recharge and fluids used in solution mining.
    Atmospheric pollutants Sources include automobile emissions, power plant smokestacks, incinerators and other industrial processes.
    Pollutants from these sources include; hydrocarbons, organic chemicals, heavy metals, sulfur and nitrogen compounds. Infiltration may carry these compounds to the groundwater.
    Urban run-off High amounts of dissolved and suspended solids from auto emissions, fluid leaks from vehicles, home use of fertilisers/pesticides, refuse and pet faeces can infiltrate groundwater from leaking storm sewers.
    Material transport and transfer Spills during material transport and transfer may result from accidents, and leaks can occur due to faulty equipment.
    A wide variety of materials can be released and infiltrate groundwater from these processes.
    Fire-fighting Disposal and seepage of contaminated fire fighting water.
    Pipelines Pipelines (i.e. sewers, natural gas, petroleum products etc) have the potential to leak and release contaminants to the groundwater.
    Old pipelines and steel pipelines subjected to corrosion are particularly of concern.
    CemeteriesA Common groundwater contaminants sourced from cemeteries include nitrate, ammonia, bacteria and a range of inorganic substances.
    In 1996 the National Survey of Cemetery Groundwaters began to assess general hydrogeochemical and microbiological conditions at 9 cemeteries across Australia.

    A Dent & Knight 1998.

    Source: Adapted from Fetter 1992.