- Title
- Contaminant transport in surface and groundwaters from wastewater systems in a coastal catchment
- Creator
- Geary, Phillip; Lucas, Steven; Shah, Vikaskumar; Dunstan, Hugh; Coombes, Peter
- Relation
- On-site ’07 Conference. Innovation and Technology for On-site Systems: Proceedings of On-site ’07 Conference (Armidale, NSW 25-27 September, 2007) p. 153-160
- Relation
- http://www.lanfaxlabs.com.au/onsite07
- Publisher
- Lanfax Laboratories
- Resource Type
- conference paper
- Date
- 2007
- Description
- The contamination of estuaries in many cases is often attributed to agricultural and urban runoff, as well as failing on-site wastewater systems. The evidence for off-site environmental impacts from large numbers of failing wastewater systems is generally ad-hoc and sparse. Data collected are often ambiguous because the currently used faecal indicators cannot be used on their own to distinguish between human and agriculturally derived faecal matter. In addition, there is difficulty in identifying direct linkages between failing systems and widespread contamination due to effluent dilution, tidal influences and the complex hydraulic connections between surface and groundwaters in estuarine catchments. Part of the Tilligerry Creek estuary along the NSW coastline was closed to shellfish harvesting in mid 2005 as monitoring by SafeFoods NSW had shown human enteric viral contamination of oyster tissues on a number of occasions. The affected part of the estuary remains closed as surveys of drainage channels have regularly detected high numbers of faecal coliform bacteria, particularly following rainfall. In 2006 further investigations were undertaken to distinguish contaminant contributions from various sources (including on-site wastewater systems) in the catchment. Rainfall, drain levels, groundwater levels and water samples were continuously monitored in an unsewered subdivision to determine its contribution to contamination in the estuary. Water samples at three surface drains and a number of groundwater bores were collected and analysed during low flow and wet weather conditions in order to establish firstly, whether there was still contamination in surface and groundwaters, and secondly, if the contaminants were present, whether they had the potential to reach the estuary and be present in estuarine waters. Faecal sterols along with other chemical and microbiological indicators were used to distinguish sources of contamination in the samples collected. These investigations did not indicate that on-site wastewater systems were contributing to contamination in the estuary and that the majority of faecal contaminants found were from agricultural runoff and domestic animals.
- Subject
- contamination; coprostanol; faecal bacteria; faecal sterols; on-site wastewater systems
- Identifier
- http://hdl.handle.net/1959.13/30459
- Identifier
- uon:2679
- Identifier
- ISBN:9780957943834
- Language
- eng
- Full Text
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