From 2005 to 2007, the export of lead carbonate from the Port of Esperance caused lead contamination in Esperance, Western Australia, after lead carbonate dust was deposited across a large part of the town of Esperance. This became a significant environmental and public health hazard, requiring a large-scale cleanup costing millions of dollars, and lasting until 2012. A parliamentary inquiry faulted the Esperance Port Authority, Magellan Metals, and the Department of Environmental Regulation (DER).
Background
editEsperance is a town in the Goldfields-Esperance region of Western Australia. It is a significant export hub due to its deepwater port. Various products are exported from the port, including grain, iron ore and nickel.[1]
Magellan Metals operated a mine at Wiluna. This mine targeted a body of lead ore, in the form of cerussite which is mineral lead carbonate. Once mined, the lead carbonate was first crushed, then concentrated using a flotation process, before being dried for transport. The lead concentrate was loaded into tranport containers, called "kibbles". These are a large container whoch are handled using front-end loaders, and have a semi-closed top design using a sheet anchored at two ends of the container. Once in the kibbles, the lead concentrate was transported via a combination of road and rail transport to the port of Esperance for export.[2]
Contamination event
editBeginning in July 2005, and continuing until March 2007, the lead carbonate concentrate from the Magellan mine in Wiluna was exported via the port of Esperance. The lead carbonate concentrate was moved by rail into Esperance Port, where it was unloaded from the kibbles onto a conveyer system. The concentrate was then moved by conveyer to bulk carriers and loaded.[2][3]
The subsequent inquiry identified numerous areas where lead carbonate dust could escape, falling into several broad areas. It could escape from the kibbles, as whilst they were covered, the covering was only anchored at two opposite ends, allowing dust to escape through the centre. Secondly, it could escape during the handling process at the port, where the lead concentrate was loaded onto conveyers and moved to the berth. This was due to the lack of sufficient covering of the loading points, and the lack of covering of several coveyers involved in handling the lead concentrate. Thirdly, it was able to escape from the ships themselves, before the holds were sealed. The escape of the lead carbonate dust was also facilitated by the strong winds that Esperance experiences, which come off the Southern Ocean.[2][4]
Bird deaths
editBeginning in December 2006, an unusual number of bird deaths occurred in Esperance, drawing attention to a potential health hazard.[3] At the time, the DEC was occupied with the bushfire season, and it was March 2007 before the issue was attended to.[2] The dead birds were tested, and high levels of lead were found in the brains, livers, and kidneys of the birds. As a result, in March 2007 lead exports from the Port of Esperance were stopped.[2][3] Around 4,000 birds died. It was subsequently determined that the lead poisoning, whilst it was not directly the cause of the birds deaths, it had increased the birds susceptibility to a heatwave which was passing through the town.[5]
Human health concerns
editFollowing the discovery of lead in the dead birds, concerns immediately arose about the scale of the issue, and the effects that it could have on human health. Residents were concerned about the impact of the lead contamination on human health, in addition to its environmental impact.[3] There were serious concerns about the safety of rain water. Many houses in Esperance used rainwater collected from the roof for drinking, due to issues with the taste of local groundwater. Dust from the port would collect on the roofs of houses, and would be washed into the rainwater tanks when it rained. This would effectively concentrate the lead in the rainwater tanks.[2] Residents were concerned about the safety of their home grown fruit and vegetables and locally caught seafood[3], as high levels of lead had also been found in the harbour, levels which had not been present in 2004.[2] Parents of young children were especially concerned that the lead contamination of their homes and environment had impacted on the blood lead levels in their children and that it would have a lasting impact on intellectual development of their children.[3]
Lead is a known cumulative toxin that can affect the central nervous system. It is also known that children exposed to levels of lead can experience neuro-developmental issues. Infants and those with impaired kidney or liver function may be particularly at risk. At the time, the World Health Organisation set a limit of 10 micrograms per decilitre as requiring intervention in children. Of the 2,695 individuals (adults and children) who were tested across the Esperance townsite, 31 were found to have blood lead levels above 10 µg/dl. Of these 7 were children under 5 years of age.[3]
Cleanup
editThe cleanup process was overseen by the Department of Transport, and lasted until 2012. It required the cleaning of contaminated areas of 1775 properties,[6] including roofs, gutters, rainwater tanks, roof spaces, interiors, and soil. This involved conducting swabs to determine the extent of contamination, and what cleanup was required. The processes for cleaning included: washing, with the run-off collected and removed for disposal; vacuuming; soil removal; and ongoing monitoring.[7] The total cost of the cleanup was A$27,500,000.[8] Magellan Metals was required to pay $9 million towards the cleanup cost. The cleanup was finally declared complete on 12 August 2012, after a 2 year monitoring program and subsequent independent review found no recurring contamination of the town.[8][9]
Inquiry
editA parliamentary inquiry was launched into the contamination, and released its report on 6 September 2007. The report faulted several parties and identified the sequence of failures that lead to a major lead contamination event, and identified several parties responsible for the failures, including Esperance Port Authority, Magellan Metals, the DEC, and the transport company contracted to deliver the goods to the port, BIS Industrial Logistics.
Role of the Esperance Port Authority
editThe Port Authority was harshly criticised for its role in the contamination.
References
edit- ^ Winters, M. T. (2009). Children's exposure to lead and nickel in Esperance – A case study (Thesis).
- ^ a b c d e f g Education and Health Standing Committee (September 2007). Inquiry Into the Cause and Extent of Lead Pollution in the Esperance Area (PDF). State Law Publisher, for the Legislative Assembly, Parliament of Western Australia. ISBN 978-1-921355-19-6.
- ^ a b c d e f g McCafferty, P. B.; Devenish, M.; Burton, H. M.; Jackson, M.; North, M.; Winchester, W. (2013). "Assessment and Remediation of Lead Contamination in Esperance, Western Australia". E3S Web of Conferences. 1: 10002. doi:10.1051/e3sconf/20130110002.
- ^ Gulson, Brian; Korsch, Michael; Matisons, Martin; Douglas, Charles; Gillam, Lindsay; McLaughlin, Virginia (2009). "Windblown Lead Carbonate as the Main Source of Lead in Blood of Children from a Seaside Community: An Example of Local Birds as "Canaries in the Mine"". Environmental Health Perspectives. 117 (1): 148–154. doi:10.1289/ehp.11577. PMC 2627859. PMID 19165402.
- ^ "Solving the mystery of mass bird deaths – ChemCentre".
- ^ "Esperance's lead poisoning disaster finally cleaned up". 31 May 2012.
- ^ "Esperance Cleanup and Recovery Project, Lead Cleanup and Recovery Plan, An Overview of the Sampling and Cleaning Process" (PDF). Department of Transport. 7 April 2011.
- ^ a b "Media Statements - Esperance lead clean-up complete". 16 August 2012.
- ^ "Esperance lead cleanup complete". 16 August 2012.
This article incorporates text from a scholarly publication published under a copyright license that allows anyone to reuse, revise, remix and redistribute the materials in any form for any purpose: McCafferty, P. B.; Devenish, M.; Burton, H. M.; Jackson, M.; North, M.; Winchester, W. (2013). "Assessment and Remediation of Lead Contamination in Esperance, Western Australia". E3S Web of Conferences. 1: 10002. doi:10.1051/e3sconf/20130110002. Please check the source for the exact licensing terms.