Solomontown, Port Pirie
Soil vapour tests conducted in December 2010 and January 2011 found elevated levels of chemicals underground in road verges and footpaths. These chemicals have the potential to migrate through the soil and into homes.
The chemicals found were those typically associated with old gasworks activities and include benzene, total petroleum hydrocarbons, naphthalene and ammonia. These chemicals can present a risk to human health if they migrate into, and build up within, the air within houses.
The EPA conducted a doorknocking exercise to about 100 homes in Solomontown.
Results of air sampling in homes by the EPA and assessment by SA Health have found evidence of soil vapour intrusion. SA Health has concluded that, overall, at the time of sample collection, there were no contaminants reported that indicated acute risks to human health.
SA Health also concluded that in some locations levels of benzene were above World Health Organization (WHO) guideline values.
The EPA has installed indoor air purification equipment in the five homes where benzene was detected at levels exceeding or approaching the WHO guideline value, and will continue to monitor benzene levels.
Technical reports on this investigation are available on the public register.
- Media release, 19 May 2011 | 1 March 2011
- Letters to residents, 18 May 2011 | 1 March 2011
- SA Health Fact Sheet, Benzene
- Map of area under investigation | 1 March 2011 | 23 December 2010
Frequently asked questions
What are the results of the indoor air testing undertaken in March?
In March 2011 the EPA sought consent from residents in Solomontown to undertake air sampling within their homes. This testing was required to determine if chemical substances found within the soil at some nearby locations had migrated into houses and posed a risk.
As a result 38 homes were identified in the area bounded by King Street, Alpha Terrace, Albert Street and Parks Street Solomontown for voluntary indoor air testing.
The results of this sampling and assessment by the EPA and SA Health have identified there is evidence of soil vapour intrusion, with chemical substances detected in a small number of homes at near or above guideline levels. Two homes recorded levels of benzene above World Health Organization recommended guidelines and three homes recorded levels near the guidelines.
What is being done to improve air quality in these homes?
The EPA and SA Health are talking directly with owners/residents of homes where chemical substances were detected near or above the guideline levels, regarding the results. The EPA and SA Health will also be taking immediate action to improve air quality in these homes.
Portable indoor air purifying equipment was temporarily provided to the five affected homes with the agreement of residents and closely monitored by the EPA and SA Health while more permanent management options could be explored in consultation with the residents and owners.
I live nearby a house where indoor air quality testing was done. How can I be sure my house is clear?
The EPA and SA Health will develop an expanded air sampling program for Solomontown, including re-offering inhome testing to residents who had previously declined. We will notify you when this additional sampling will be available and let you know how you can participate.
How did the EPA become aware of the contamination?
Origin Energy Pty Ltd (Origin) as current owners of the site, as part of their ongoing assessment process identified benzene in the air voids within the soil (soil vapour) on-site. This information was provided to the EPA, and subsequently after consultation with the Department of Health, an EPA assessment was undertaken at off-site locations surrounding the former gasworks site to determine if the chemical substances were also present off-site.
Prior to this, Origin had informed the EPA in 2004 of site contamination of groundwater at the former gasworks site and at off-site locations in Solomontown. Testing of the groundwater bores found benzene, toluene, ethylbenzene, xylenes (BTEX), total petroleum hydrocarbons (TPH), ammonia and naphthalene in the groundwater. As a result a Groundwater Exclusion Zone (GEZ) was established by the Department of Water, Land, Biodiversity and Conservation for the impacted area in 2006.
There is no evidence at this time that the former gasworks site is the source of the contamination.
What sampling has the EPA undertaken to date?
In late December 2010 the EPA undertook shallow soil vapour sampling on council property (the road verges) within the residential area to determine whether the chemical substances of concern were present. The EPA received the results of this sampling in late January 2011. The results showed that toluene, ethylbenzene, xylenes and other related chemical substances were present in soil vapour on the road verges surrounding the former gasworks site.
The EPA liaised with SA Health and determined that it was appropriate to test the indoor air quality in houses in the area as a precaution. This indoor air quality testing was undertaken in March 2011. The testing enabled SA Health to undertake a human health risk assessment to determine whether there is any health risk to people living in the area.
Why is it necessary to sample the air quality within houses?
The results of the EPA’s initial sampling on council property in December 2010 only informed us that toluene, ethylbenzene, xylenes and other related chemical substances are present underground in soil vapour near the ground surface on the road verges. The indoor air quality sampling determines whether people are being exposed to these chemical substances, and if so, at what level.
In the event that these chemical substances are found in the air in houses, the results from the indoor air sampling are used by SA Health to conduct an exposure assessment for people living within the area. This assessment then determines any health risk that may be present.
It should also be noted that people are exposed to 'background exposures' in our everyday life (Are we exposed to BTEX associated chemical substances in the community?)
How is the indoor air sampling in houses undertaken?
Indoor air quality is tested by using special air samplers (radiello tubes) that collect air through the tube. The air samplers are left in the residential properties for up to two weeks to collect a sufficient sample. The air samplers are sent to an accredited laboratory to be analysed.
The radiello air sampling technique is used because it is very sensitive in detecting chemicals associated with former gasworks activities in the air, while causing little disturbance to households. The samplers are a small device approximately 60 mm long that can be attached to a curtain rail, etc.
Samples are collected from different locations in houses, including living and sleeping areas.
As part of the sampling program, the EPA also tests the ambient (outdoor) air in the area, for comparison with the air inside the houses. The air in one or two houses located away from the affected area is also tested to provide further background information.
How long does it take to get results from the air sampling within houses?
Once the samples are collected they are immediately sent to an accredited laboratory for analysis. Results are typically received about a month later. Assessment of the results to determine their significance for health risks to human health is then undertaken by SA Health and the EPA. This assessment may take a further few weeks.
What if I don’t want the air in my house sampled?
Written permission is sought from owners and occupiers prior to the commencement of indoor air sampling. The final say as to whether the testing is carried out rests with the owner/occupier.
It is necessary to seek the owner’s permission to sample because information relating to the properties will be placed on the EPA Public Register as a result of the testing. Owners will also have obligations to identify the information and results through Regulations under the Land & Business (Sale and Conveyancing Act 1994) when the property is sold. The EPA and SA Health strongly recommend that the sampling be undertaken, however the final say as to whether the testing is undertaken rests with the vendor.
What is BTEX?
BTEX is an acronym that stands for a group of chemicals comprising benzene, toluene, ethylbenzene and xylenes. These compounds are some of the lighter aromatic (ring-shaped molecules of low molecular weight) volatile organic compounds found in petrol and petroleum derived products. They are also typically associated with gasworks operations.
What is TPH?
TPH is an acronym that stands for total petroleum hydrocarbons, a term used to describe a vast (several hundreds) family of chemicals originating from crude oil, and present in oil derived products, such as petroleum products. They are called hydrocarbons because almost all of them are made entirely of hydrogen and carbon. TPH are distributed widely throughout the environment. TPH exist as a mixture and the composition of the mixture varies depending on the original composition of the crude oil and the products derived from it. The term 'total' refers to the fact that it is most practical to measure these chemicals as a group when screening for environmental contamination.
What is ammonia?
Ammonia is a compound of nitrogen and hydrogen. It is a caustic (high pH), colourless liquid with a characteristic pungent smell. Ammonia is a naturally occurring chemical compound and is an important source of nutrition for plants. It is used widely in chemical and pharmaceutical synthesis and cleaning products, including household cleaners. Ammonia is a common contaminant at old gasworks sites.
What is naphthalene?
Naphthalene is an aromatic (ring-shaped) polycyclic aromatic hydrocarbon with distinctive odour. It is one of the traditional primary ingredients used in mothballs. Naphthalene is used in the production of plasticisers, pharmaceuticals, insect repellents and other products. It is made from coal tar or during petroleum refining. Cigarette smoke contains naphthalene. Naphthalene is a common contaminant found at former gas works sites.
What is the EPA doing to determine the source of the contamination?
The EPA is investigating potential sources of contamination in the area. This investigation includes a study of historical activities undertaken in the area and having discussions with local landowners whose sites may be potential sources.
How can contact with chemical substances occur if they are present in the vapours within the soil?
Exposure can occur if the chemicals migrate through the soil pore spaces to the ground surface, and then find their way through cracks and holes in the slab, floor or walls of the building. If ventilation is low, vapours may then accumulate within building spaces and be inhaled by anyone in the building.
How can contact with chemical substances occur if they are in groundwater (bore water)?
Exposure can occur if contaminated groundwater is used for drinking or cooking and in showers, swimming pools and gardens (via ingestion, inhalation or through the skin).
What does the government do if chemical substances are found in the indoor air in houses?
If chemical substances are found in the indoor air in houses, the appropriate action to be taken depends on which chemicals are found and at what levels. The human health risk assessment conducted by SA Health is used to determine what action is appropriate.
The appropriate actions may include:
- No action, as the chemicals are considered to be present at safe levels.
- Periodic monitoring to check variation in the levels of the chemicals in air over time.
- Temporary relocation to other accommodation.
- Remediation measures to reduce the level of the chemicals in indoor air to safe levels. For example, this could include modifications to the ventilation in affected houses, the installation of a subsoil gas extraction network, source treatment/removal, etc.
It is not possible to know prior to the results of testing being available, what management actions, if any, may be required.
Is it safe to breathe the outdoor air in the area?
As these chemicals are likely to be emitted at a very low rate from the soils and quickly dispersed in the outdoor air, EPA and SA Health has no concerns about the outdoor air quality in the area.
This has been confirmed by the results of outdoor air testing.
How were the houses to be sampled chosen?
Houses sampled in March 2011 fall within the area where chemical substances were detected during the sampling conducted on public land during December 2010.
I live in the area adjacent to the area where the houses are being sampled – what testing is being done to prove that my house is safe to live in?
The EPA holds no information about the presence of chemicals in the residential area outside of the area where indoor air sampling is being conducted (ie the area bounded by Alpha Terrace, King Street, Parks Street and Albert Terrace).
How can BTEX, TPH, ammonia and naphthalene affect health?
SA Health advises that the effects on human health depend on a number of factors, such as how long people may be exposed, and how much of each chemical is present. Other factors include a person’s health and age.
Breathing very high levels of benzene can cause drowsiness, dizziness, rapid heart rates, headaches, tremors, confusion and unconsciousness, and can result in death. Eating or drinking foods containing high levels of benzene can cause vomiting, irritation of the stomach, dizziness, sleepiness, convulsions, rapid heart rates, and death. The major effect of benzene from long-term exposure is on the blood. Benzene causes harmful effects on the bone marrow and can lead to a decrease in red blood cells resulting in anaemia. It can also cause excessive bleeding and affect the immune system, increasing the chance for infection. Benzene is classified as known human carcinogen. Long-term exposure to high levels of benzene in the air can cause leukaemia, particularly acute myeloid leukaemia, often referred to as AML.
Toluene may affect the nervous system. Low to moderate levels can cause tiredness, confusion, weakness, drunken-type actions, memory loss, nausea, loss of appetite, and hearing and colour vision loss. Inhaling high levels of toluene in a short time can make a person feel light-headed, dizzy or sleepy. It can also cause unconsciousness and even death. Exposure to high levels of toluene over sufficient time may affect the kidneys.
Exposure to high levels of ethylbenzene in air for short periods can cause eye and throat irritation. Exposure to higher levels can result in dizziness. Exposure to relatively low concentrations of ethylbenzene in air for several weeks to years causes inner ear and kidney damage in animals.
High levels of exposure for short or long periods can cause headaches, lack of muscle coordination, dizziness, confusion and changes in ones's sense of balance. Exposure of people to high levels of xylene for short periods can also cause irritation of the skin, eyes, nose and throat, difficulty in breathing, problems with the lungs, delayed reaction time, memory difficulties, stomach discomfort, and possibly changes in the liver and kidneys. It can cause unconsciousness and even death at very high levels. No health effects have been noted at the background levels that people are exposed to on a daily basis.
TPH is a vast group of chemicals and the health effects may vary depending on what compounds comprise TPH that a person is exposed to. Some of the TPH compounds can affect the central nervous system at high levels in the air. They can cause headaches and dizziness as well as a nerve disorder called 'peripheral neuropathy' consisting of numbness in the feet and legs. Other TPH compounds can cause effects on the blood, immune system, lungs, skin and eyes. Animal studies have shown effects on the lungs, central nervous system, liver, and kidney from exposure to TPH compounds. Some TPH compounds have also been shown to affect reproduction and the developing foetus in animals.
Exposure to high levels of ammonia in air may be irritating to skin, eyes, throat, and lungs and cause coughing and burns. Lung damage and death may occur after exposure to very high concentrations of ammonia. Some people with asthma may be more sensitive to breathing ammonia than others.
Exposure to large amounts of naphthalene may damage or destroy some of the red blood cells. This could cause a condition is called haemolytic anaemia. Some symptoms of haemolytic anaemia are fatigue, lack of appetite, restlessness and pale skin. Exposure to large amounts of naphthalene may also cause nausea, vomiting, diarrhoea, blood in the urine and a yellow colour to the skin. Naphthalene is classified as possible human carcinogen.
Exposures to these chemicals may occur in the general community, for example, BTEX and TPH are compounds of petrol and BTEX and naphthalene are found in cigarette smoke in small amounts.
Ammonia can be found in some household products such as bleach and other cleaning products. Naphthalene can also be found in some household products and is best known as the traditional, primary ingredient of mothballs.
These types of exposures are referred to as 'background exposures'. As exposures to chemicals occur from many sources in our everyday life, it is desirable that action is taken to reduce or eliminate exposure where possible.
It needs to be recognised that exposure to any one chemical often occurs from multiple sources to varying degrees and it is important to reduce total exposures to the lowest amount possible. This is to ensure total exposure levels are below those that may produce effects on health.