Indicator: CO-64 Quantity of various substances discharged by offshore extraction activities

Data

The following tables show:

  • change in the number of offshore facilities reporting emissions under the NPI from 1998 to 2004;
  • change in emissions of the top six substances (in terms of quantity only) from offshore facilities;
  • change in average of these emission across offshore facilities (to take into account increasing numbers of facilities reporting).

The emissions data includes only emissions to water, not to air or land. (“Emissions to land” from offshore facilities means emissions to beneath the sea bottom.)

Number of offshore facilities reporting emissions to the NPI
Number of facilities 2003-2004 2002-2003 2001-2002 2000-2001 1999-2000 1998-1999
Total number offshore NPI facilities 32 36 37 33 23 10
Quantities (kg) of substances emitted from offshore facilities by years
Year Volatile organic compounds Hydrogen sulphide Boron and compounds Total nitrogen Manganese and compounds Total phosphorus Total number facilities reporting
1998-1999 793 0.0 0.0 60,300 0.0 17,900 10
1999-2000 22,709 0.0 64,110 232,341 0.0 52,088 23
2000-2001 21,080 0.0 62,491 239,494 0.0 8,070,982 33
2001-2002 238,812 243,000 74,487 130,895 66,839 56,739 37
2002-2003 267,328 238,000 74,092 60,528 66,178 22,650 36
2003-2004 346,955 231,000 69,411 64,797 64,686 15,743 32
Average of substance (kg) emitted across offshore facilities
Year Volatile organic compounds Hydrogen sulfide Boron and compounds Total nitrogen Manganese and compounds Total phosphorus
1998-1999 79.3 0 0 6,030 0 1,790
1999-2000 787.35 0 2,787.39 10,101.78 0 2,264.7
2000-2001 638.79 0 1,893.67 7,257.39 0 244,575.21
2001-2002 6,454.38 6,567.57 2,013.16 3,537.7 1,806.46 1,533.49
2002-2003 7,425.78 6,611.11 2,058.11 1,681.33 1,838.28 629.17
2003-2004 10,842.34 7,218.75 2,169.09 2,024.91 2,027 491.97

Source: National Pollutant Inventory 2006, Australia's national database of pollutant emissions, viewed 8 Jun 2006, http://www.npi.gov.au/

For more detail on number of facilities and quantities of substances emitted by facilities: offshore; within 10 kilometres of the coast; within 10 to 50 kilometres of the coast; and total see:

The following maps from the National Marine Atlas show the locations of offshore or and gas wells, exploration sites and infrastructure.

In relation specifically to oil spills, the Australian Maritime Safety Authority (AMSA) keeps a record of sightings and serious spills. Most of these are from shipping but some are from offshore extraction facilities. See indicator CO_27 Number, frequency, extent and volume of oil spills from all sources .

What the data mean

The total number of offshore facilities reporting emissions to water, under the NPI, has increased from 10 in 1998-99 to 32 in 2003-2004. (Note: this does not necessarily mean facilities in these locations have commenced or increased discharges during this period, only that they have commenced reporting those discharges under the NPI.)

Since 1998, the substances being discharged from offshore facilities in the largest quantities are:

  • Volatile organic compounds
  • Hydrogen sulfide
  • Boron and compounds
  • Total nitrogen
  • Manganese and compounds
  • Phosphorus

Total reported emissions of these substances seem to be increasing, with minor variations, since 1998.

Averaged over number of facilities reporting, emissions of volatile organic compounds, hydrogen sulphide and manganese and its compound have increased since emissions of these substances from offshore facilities were first reported. Average emissions of boron and its compounds, total nitrogen and total phosphorus have decreased. (Emissions of more than 8 million kilograms of phosphorus in 2000-2001 appear to be anomalous.)

Data Limitations

At this stage the apparent steady increase in reported emissions from offshore activities over the years of the NPI is probably more indicative of facilities coming on board with reporting than of actual increases in emissions. This also means that the emissions data currently reported to the NPI are likely to be a very substantial underestimate of actual emissions.

A reduction in average emissions may reflect that smaller facilities whose emissions are generally lower are the ones that have commenced reporting more recently. However, an increase in average as well as total emissions suggests that it is emissions as well as number of facilities reporting, that are increasing.

Ultimately, however, it is expected that the trends in reported emissions will be indicative of changes in actual emissions.

The data relate only to emissions from facilities that emit sufficient quantities of pollutants to be required to report under the NPI.

The table derived from the NPI shows substances by quantity, but does not show the relative harmfulness of substances by weight, for humans, other species or ecosystems. (Most is not necessarily worst.)

Data for the NPI are compiled from facility reports and are only as good as the data provided. Apparent anomalies may be due to errors in the data, or to unusual events at the facilities during the reporting year. Only the emissions, not the activities or events responsible for them, are reported to the NPI.

Issues for which this is an indicator and why

Coasts and Oceans — Direct pressure of human activities on coasts and oceans - Direct pressures of harvesting non-living materials 

Substances vary enormously in terms of what quantities are dangerous to human health and the environment. Therefore a breakdown, as far as possible, of quantities of all substances discharged from offshore exploration and extraction activities directly into marine waters is required to give an indication of the scale of this pressure.

Other indicators for this issue:

Biodiversity — Pressures on biodiversity - Pressures on marine biodiversity: pressures of energy and mineral exploration and extraction 

Discharges of pollution from off shore oil and gas facilities are a pressure on marine biodiversity. Substances vary enormously in terms of what quantities are dangerous to human health and the environment. Therefore a breakdown, as far as possible, of quantities of all substances discharged from offshore exploration and extraction activities directly into marine waters is required to give an indication of the scale of this pressure.

Other indicators for this issue:

Further Information

The National Marine Atlas (Maps 24 to 30) provides data on locations and quantities of various pollutants as at 2004: National Marine Atlas 

The National Pollutant Inventory is a web-based system that provides information about emissions of a range of substances to air, land and water. Sources include both industry facilities and diffuse sources such as motor vehicles: Australia's national database of pollutant emissions