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National Pollutant Inventory

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Tracking NPI substances

The NPI contains data on 93 substances that are emitted to the environment - our air, water or land.
The substances included in the NPI have been identified as important because of their possible health and environmental effects.
In 2007-08, 87 substances were reported to the NPI from 4116 facilities.

• 49 of the 87 NPI substances reported by facilities showed a decrease compared with 2006-07.
• The 2007-08 dataset includes new information as a result of the variation to the NPI NEPM. This covers reporting of new substances acrolein and particulate matter 2.5 (PM2.5) and the reporting of mercury at the recently reduced threshold level of 5kg.
• Acrolein has been included in the NPI reporting list owing to its toxicity, usage and potential for exposure. Acrolein is present as a product of burning or fuel combustion activities, and it is also used as a chemical intermediate for the manufacture of plastics or colloidal forms of metals. Acrolein is an algal control agent, and has been found in hazardous waste sites.
• The PM2.5 data is now included due to increasing concern over the effects of smaller particles on human health, and will help establish the contribution of smaller particles from industrial combustion sources at a local level. The majority of PM2.5 emissions come from the electricity generation and mining sectors.
• Given that environmental contamination with mercury is an ongoing concern and adverse effects may occur from relatively low levels of mercury, the new data also reflect more detailed reporting on mercury, with a reduced threshold level of 5kg.
• Reporting of polychlorinated biphenyls (PCBs) is also required for the first time. While PCBs are not likely to be a major environmental emission, their management as transfers to a final destination will be important. Transfers are the movement of NPI substances on-site or off-site for containment, destruction or reuse. It is now a requirement for industry to collect data on the transfer of waste, and this data will begin to be published in March 2010.
• Air pollutants, such as oxides of nitrogen and particulate matter 10 (PM10) showed little change, while reported sulfur dioxide emissions across the nation showed an 8% increase. Carbon monoxide and lead and compounds emissions also showed a small increase of 3%.
• Air toxic pollutants, such as benzene and toluene, showed a decrease in reported emissions in 2007-08. There was a 48% decrease in emissions of polycyclic aromatic hydrocarbons, while this year reported emissions of formaldehyde rose by 41%.
• Substances that had a significant decrease in reported emissions and a similar number of reporting facilities as last year include a 16% decrease in benzene mainly from basic ferrous metal manufacturing and petroleum refining.
• Substances that had a significant increase in reported emissions and a similar number of reporting facilities as last year include formaldehyde mainly from petroleum refining, and cadmium and its compounds mainly from basic non-ferrous metal manufacturing.

The following examples show the type of substance information you can find on the NPI web site.

Sulfur dioxide emissions

• Australian Environment Ministers have formally listed sulfur dioxide as a criterion air pollutant under the National Environment Protection Measure for Ambient Air Quality. Australia has set national standards for sulfur dioxide in outdoor (ambient) air.
• Sulfur dioxide can be harmful to human health when it is inhaled. People living in cities may be exposed to low levels of sulfur dioxide every day by living in or near industrial areas, or near freeways and busy roads. The Australian Government is taking steps to manage and reduce the amount of sulfur dioxide produced by implementing national fuel quality standards.
• The main source of sulfur dioxide in the air is industrial activity that processes materials that contain sulfur, such as the generation of electricity from coal, oil or gas that contains sulfur. Metal smelting of ores containing sulfides, such as lead, silver and zinc, also emit sulfur dioxide when they are processed.
• The largest industry source of sulfur dioxide in 2007-08 was electricity generation.
• 1826 facilities emitted 1.4 million tonnes of sulfur dioxide during the 2007-08 reporting year.
• Emissions increased by 8% compared with the previous year.
• Emissions were mainly to air, with minimal amounts to water and land.
• Sulfur dioxide also emitted from non-industry sources, particularly from fuel combustion in small facilities that are not required to report to the NPI because they do not trip the threshold.

This graph shows the emissions of sulfur dioxide for each reporting year and the number of facilities reporting the substance to the NPI.

Chlorine emissions

• Chlorine is used in the manufacture of chlorinated organic chemicals, plastics and chlorinated lime. Other uses include water purification, as a bleaching agent in pulp and paper manufacturing, and as a disinfectant in human drinking water treatment systems, swimming pool water systems, industrial ponds and sewage systems. Chlorine also maybe used as an algaecide in commercial and industrial water-cooling tower systems.
• Exposure to chlorine can cause burning of the eyes, nose and mouth; as the concentration increases, the effects become more severe including nausea and vomiting, difficulty breathing and burning chest pain.
• The dominant exposure for the general public is likely to be from drinking chlorinated drinking water and using household chemicals, such as bleach and pool chemicals, that may release chlorine during use.
• The largest industry source of chlorine is waste treatment, disposal and remediation services.
• 316 facilities emitted 120 000 kilograms of chlorine during the 2007-08 reporting year. Emissions decreased by 20% compared with the previous year.
• Chlorine is also emitted from non-industry sources such as swimming pools and bushfires.
• Chlorine is emitted mainly to water and land, with a small amount to air.

This graph shows the emissions of chlorine for each reporting year and the number of facilities reporting the substance to the NPI. It was not mandatory for industry to report chlorine emissions until the 2001-02 reporting year.

Total Nitrogen emissions

• Nitrogen is an essential nutrient for all forms of life. Total Nitrogen is defined for the NPI as compounds that give rise to nitrate and nitrite ions. This is a very broad group including many natural and man-made substances, either containing nitrates or nitrites or decomposing into either or both of them.
• A general concern in relation to Total Nitrogen is its environmental effects, where elevated levels of nitrogen (and phosphorus) can cause enhanced algal growth. This may eventually manifest itself as blue-green algal blooms which can affect human health through contact or consumption.
• The biggest industry source of Total Nitrogen emissions this reporting year is water supply, sewerage and drainage services.
• 241 facilities emitted 34 million kilograms of Total Nitrogen during the 2007-08 reporting year.
• Emissions increased by 5% compared with the previous year.
• Emissions were to water only.
• The major diffuse source of Total Nitrogen is from catchment runoff and is typically derived from soil, plant and animal material associated with agricultural land uses.

This graph shows the emissions of Total Nitrogen for each reporting year and the number of facilities reporting the substance to the NPI.

Using the NPI data

• When using NPI data it is important that the emissions of different substances are not added together as this provides misleading information.
• The NPI comprises estimated emissions. The techniques used to estimate emissions have been approved by Australian Government, and state and territory environment agencies but it should be noted that the accuracy of these estimates is likely to vary according to the technique used.
• The 93 NPI substances span a wide range of toxicities. A small amount of a highly toxic substance may be of more concern than a larger emission of a less toxic substance.

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