❓ A parliamentary question addresses concerns about the environmental impact of biowaste sludge disposal from wastewater treatment plants onto the Harvey Pines in Myalup, focusing on nutrient levels, potential harm to market gardens and water sources, and effects on nearby horse studs. The response provides data and assurances regarding safety measures.
AnsweredQoN 6033Legislative Assembly
QuestionView source ↗
Given that in 2008 the Department of Environment issued a license to the Forest Products Commission to allow it to annually dump 15,000 dry tonnes of biowaste sludge from Waterman and Beenyup waste-water treatment plants onto the Harvey Pines in Myalup:
(a) what are the nutrient levels in monitoring bores east of Old Coast Road, Myalup;
(b) what effect will a spike in nitrogen levels have on the market gardens in the area;
(c) can the people of Western Australia have confidence that Escherichia coli (E. coli) bacteria is not being pumped onto crops;
(d) what is being done to protect from nutrient run-off into Lake Preston and the Myalla Water mound; and
(e) what effect does dumping of bio-solids have on nearby horse studs, given the recent discovery of a new fly species?
(a) what are the nutrient levels in monitoring bores east of Old Coast Road, Myalup;
(b) what effect will a spike in nitrogen levels have on the market gardens in the area;
(c) can the people of Western Australia have confidence that Escherichia coli (E. coli) bacteria is not being pumped onto crops;
(d) what is being done to protect from nutrient run-off into Lake Preston and the Myalla Water mound; and
(e) what effect does dumping of bio-solids have on nearby horse studs, given the recent discovery of a new fly species?
AnswerView source ↗
Answered
27 September 2011
Responded by
Minister for Environment; Water
Response time
28 days
a) Nutrients levels from monitoring bores located east of Old Coast Road in the Lake Preston South Subarea of the South West Coastal Groundwater Area in the locality of Myalup show a range of <0.01 milligrams per litre (mg/L) to 19.51mg/L with a median value of 1.7mg/L from March/April 2010.
(b) The application rate for biosolids, as specified in the licence conditions, is set at a level so that nitrogen will be taken up by the plantations, thereby limiting the entry of nitrogen into the groundwater. Provided that the application of biosolids to the plantations conforms with the levels set in the licence conditions, they should not cause a spike in nitrogen levels in groundwater used by market gardeners.
(c) Several studies have been completed examining the risk of pathogen contamination to soil, water resources and crops from the application of biosolids to plantations. An initial study, titled '
Application of Biosolids to the Pine Plantations of the Swan
Coastal Plain - Final Report of a Three Year Study to the Water Corporation of
Western Australia
'
2003
,by the then Department of Conservation and LandManagement specific to the Myalup plantation biosolids disposal area, reported that no nutrients, pathogens or metals above acceptable limits were detected over the three years of monitoring groundwater at Myalup.
The study reported that, during the initial years of monitoring, all indictor pathogens (including E. coli) were observed to be at low levels of risk to public health. Based on this study, the public can be confident that biosolids applied to the Myalup plantation pose minimal risk to groundwater and public health when application rates are managed according to the licence conditions.
(d) Lake Preston and the Myalla Water Mound are protected from nutrient leaching by the vertical separation of the biosolids from the water table, and licence conditions that match the rate of application to the rate of absorption of nutrients by the plantation. The soils in the plantations are not conducive to surface nutrient 'run-off'.
(e) This question should be referred to the Minister for Agriculture and Food.
The Department of Environment and Conservation has advised that fly emergence from biosolids applied at the Myalup plantation is monitored by the Water Corporation periodically during the application program. Monitoring began in June 2011, with no flies emerging from samples up to and including 20
July 2011.
Biosolids are applied at Myalup during the cooler months of the year when there is typically no fly emergence.
Notice: This document is created or edited using unregistered or evaluation copy of rtLib valid for testing or development purposes only. To use it for productive or any other purposes please register it. You may purchase the license on
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(b) The application rate for biosolids, as specified in the licence conditions, is set at a level so that nitrogen will be taken up by the plantations, thereby limiting the entry of nitrogen into the groundwater. Provided that the application of biosolids to the plantations conforms with the levels set in the licence conditions, they should not cause a spike in nitrogen levels in groundwater used by market gardeners.
(c) Several studies have been completed examining the risk of pathogen contamination to soil, water resources and crops from the application of biosolids to plantations. An initial study, titled '
Application of Biosolids to the Pine Plantations of the Swan
Coastal Plain - Final Report of a Three Year Study to the Water Corporation of
Western Australia
'
2003
,by the then Department of Conservation and LandManagement specific to the Myalup plantation biosolids disposal area, reported that no nutrients, pathogens or metals above acceptable limits were detected over the three years of monitoring groundwater at Myalup.
The study reported that, during the initial years of monitoring, all indictor pathogens (including E. coli) were observed to be at low levels of risk to public health. Based on this study, the public can be confident that biosolids applied to the Myalup plantation pose minimal risk to groundwater and public health when application rates are managed according to the licence conditions.
(d) Lake Preston and the Myalla Water Mound are protected from nutrient leaching by the vertical separation of the biosolids from the water table, and licence conditions that match the rate of application to the rate of absorption of nutrients by the plantation. The soils in the plantations are not conducive to surface nutrient 'run-off'.
(e) This question should be referred to the Minister for Agriculture and Food.
The Department of Environment and Conservation has advised that fly emergence from biosolids applied at the Myalup plantation is monitored by the Water Corporation periodically during the application program. Monitoring began in June 2011, with no flies emerging from samples up to and including 20
July 2011.
Biosolids are applied at Myalup during the cooler months of the year when there is typically no fly emergence.
Notice: This document is created or edited using unregistered or evaluation copy of rtLib valid for testing or development purposes only. To use it for productive or any other purposes please register it. You may purchase the license on
http://www.rtlib.com
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