Mark Lund (1), Helen Martin (1),
Historical association of wetlands and rivers in the Perth-Bunbury region
Funding: Water and Rivers Commission (Western Australia)
This is a slightly modified extract from the report – Lund, M.A. and Martin, H.C. (1996) Historical association of wetlands and rivers in the Perth-Bunbury region. Water Resource Technical Series. Water and Rivers Commission Report WRT3. Perth, Western Australia. The full report also includes information on each Shire and Suburb in the Perth-Bunbury region.
The Dutch were the first Europeans to discover Western Australia (WA) in 1616 and over subsequent years mapped the coast and lost many ships to reefs. The Dutch found that the land contained little in terms of accessible supplies and the Aboriginal people were seen as `fierce savages’ (Appleyard & Manford 1979). As a result they made no attempt to claim the land. Between the 1700’s and early 1800’s both French and British explorers mapped the WA coastline, although it was a British explorer (George Vancouver) who found the best natural harbour on the coast which he named King George Sound (in present day Albany). This provided a valuable base for more detailed explorations of the coast. Rivalry between British and French interests allowed Captain James Stirling to persuade Governor Darling of the New South Wales Colony to allow him to explore the Swan River with the intention of determining its suitability as a site for a new colony. His reports led to the eventual establishment of a British colony on the Swan River in 1829.
Sulfidic minerals release acidity and metals as AMD in Collie pit lakes
General History of Early European Colonisation
The early settlement of Perth and other cities/towns within the region has been well documented by historians (eg. Appleyard & Manford 1979; Stannage 1981; Ewers 1971; Barker & Laurie 1992; Richards 1978). Typically in these accounts, the settlers’ use and needs in relation to water has been secondary to the political and social intrigues of the times. The publication of `Water: The abiding challenge’ by Morony (1980) has remedied this situation for Perth. The book provides a comprehensive history of water supply, drainage, and sewage in Perth. No similar histories have been written for the other cities/towns within the study area.
Captain Stirling visited the Swan River in March 1827 and spent 9 days exploring (Markey 1977). He concluded that the area was supplied with a wealth of freshwater sources, including wetlands, streams, springs and accessible groundwater. He also concluded that the climate was moderate. At the beginning of autumn, he was fortunate to find the area with ample water supplies. On his return in 1829, he located the Swan River Colony (later renamed Perth) on the northern banks of the Swan River, just east of Mount Eliza. Why he choose this particular site has been the cause for much speculation (see Markey 1977 and Seddon & Ravine 1986). The colony was surrounded to the north by ten wetlands which at times of high rainfall joined and flowed through Claise Brook to the Swan River (Figure 2). In the colony’s first summer, it became apparent that the wetlands were an unreliable source of water and many settlers resorted to using groundwater extracted from shallow wells. The same situation occurred in Fremantle where the two inland wetlands also proved unreliable as a water resource and were quickly filled in and built over. Once the wetlands lost their importance for a water supply they turned from assets to liabilities restricting further growth of the city and posing drainage problems.
A timeline of water-related events in the history of the region
The following is a summary of major historic events that are related to water in Region, although most of the information concerns Perth (based on information from Ewers 1971; Jarvis 1979; Markey 1977; Morony 1980; Parker 1983; Seddon & Ravine 1986; Tauman 1978; WAWA 1994; WAWRC 1992).
This stage required the compilation of existing data on the chemical, physical and biological aspects of Collie pit lakes from the peer-reviewed and available grey literature. As there was little data publicly available on Collie pit lakes, this data compilation made extensive use of unpublished MiWER data. Project members from the MiWER team have an extensive dataset on water quality of most Collie pit lakes extending back more than a decade and also collected new data specifically for the health study. In addition, existing monitoring data was used to determine concentrations of relevant parameters and their likely health effects. The literature review outlined likely health effects associated with water temperature and other issues such as chemical injury. The data collated in Task 1 were used to identify potential chemical and biological human health risks associated with pit lakes in Collie. A further literature review also examined physical risks such as injury, water temperature and drowning.
Stage 2: Community Survey
To assess the use and perceived issues of using pit lakes a community survey was undertaken via administration of a postal questionnaire. The questionnaire was focussed on finding out how many people use the pit lakes, the purposes for which they use the lake, how often they use the lakes and for how long they have used the lakes and how they would like to use the lakes. We also obtained data on health issues that may be associated with pit lake water and other potential confounding factors. The questionnaire was designed based on the literature review. The population of Collie and surrounds is 7,194 persons and we aimed to obtain information from approximately 10% of the population. As response fractions are often low 1,500 questionnaires were posted to a random sample of residents of Collie. The selection was based on the electoral roll. A reply paid envelope was provided. The data collected via questionnaire was analysed and the information informed the screening health risk assessment in Stage 3. A report on the questionnaire was then developed and provided the Department with a variety of information on actual and perceived issues associated with pit lakes in the area.
Stage 3: Screening Health Risk Assessment.
Health risk assessment is a systematic, transparent process of assessing the potential risks associated with exposure to environmental and physical parameters. It uses a standard methodology which is routinely accepted worldwide and provides managers with good information on how to prevent and minimise both actual and perceived risks. Based on Stages 1 and 2 human health risks were determined based on the likelihood of them occurring, the consequence if they occur and therefore an assessment of the significance of the risk. This process also enabled the development of triggers to manage issues to prevent risks from occurring. This stage also identified any issues that required further investigation.
- The potential for health impacts from recreational pit lakes use in the Collie Basin was assessed by a review of available literature; the results of a community-based questionnaire and a screening-level risk assessment. Three pit lakes were the subject of the assessment, Black Diamond, Lake Stockton and Lake Kepwari. Results of this assessment need to be considered in light of a small response to the questionnaire (20% of the survey population) and a paucity of good quality water quality characteristics. Some recommendations have been made to address the shortfall in the information.
- A review of the literature reveals that there is limited information on recreational use of pit lakes. Nothing was found on the potential for health impacts other than injury. Results from health studies of the effects of pH, temperature, clarity and water quality (both biological and chemical) in other settings suggest these can have a significant impact on health depending on the type of activities an individual undertakes and their underlying health status.
- Sixty-two percent of respondents to the community-based questionnaire used the lakes for recreational purposes. Most respondents were male aged >50 years and spent an average of 2 days per month at the lakes in the warmer months of the year. There were few respondents who recreated at the lakes all year round. A fifth of respondents had young children who visited the lakes. Most respondents who visited the lakes visited Black Diamond and Lake Stockton and while Lake Kepwari was closed to the public, nearly 30% reported visiting and undertaking water-based activities at the Lake. Most respondents reported swimming, wading and picnicking as the most popular recreational pursuits.
- Thirty eight percent of respondents reported one or more health effects following use of the pit lakes. It must be noted that no information was collected on pre-existing health status. Of the symptoms reported, sore eyes were the most common followed by skin rashes and irritations. Only 3% of respondents reported symptoms every time they used the lakes and this was reported most often in relation to Black Diamond. Acidity could lead to such symptoms and potentially affect sensitivity to metals from skin barrier disruption caused by low pH.
- Water quality of the pit lakes is variable with most parameters measured at detection limits well above current ANZECC/ARMCANZ (2000) recreational water quality guidelines for swimming. To date, assessment of water quality at the lakes has been undertaken with an environmental focus. Water samples have been used to assess remediation techniques and ecological values. This has reduced the ability to comment on whether water quality parameters do or do not present health risks. An ad hoc collection of water samples in 2010 with analysis using detection limits below ANZECC/ARMCANZ (2000) guidelines was undertaken during the preparation of this report. These results differed from existing data with fewer metals at elevated concentrations. It is recommended that future monitoring should be undertaken using detection limits suitable for assessing health. These can be found for each physical and chemical parameter in the Australian Drinking Water Guidelines (ANZECC/ARMCANZ 2000).
- Of the small amount of data available (from the MiWER database) to assess the potential for health effects, mercury concentrations at Black Diamond are significantly higher than recreational water quality guidelines. Arsenic concentrations at Lake Stockton were also elevated and aluminium is above ANZECC/ARMCANZ (2000) recreational water quality guidelines at all three lakes. Iron and manganese were above recreational water guidelines at Lake Kepwari. The limited data from the analysis undertaken in April 2010 indicates that current mercury and arsenic concentrations are below ANZECC/ARMCANZ guidelines. Aluminium concentrations are elevated and above guidelines values at all three lakes.
- No vector-borne disease potential has been identified and the presence of the nuisance midge Ceratopogonidae is not viewed as a significant health risk. Respondents to the questionnaire did not indicate this was an issue of concern. The potential exists however for biological factors and in particular microbial contamination to be an issue with the pit lakes. Future monitoring and management should address this issue.
- A screening-level health risk assessment was conducted for mercury, aluminium, manganese and arsenic concentrations in surface water. It found that the frequency of recreational use was too low to result in significant health effects despite the elevated concentrations. The potential for health impacts from exposure to mercury increases significantly if seafood is consumed. Because of the low response fraction to the survey, we cannot estimate the true frequency and duration of use of the lakes with any certainty. These results must also be treated with caution due to the lack of information on other parameters such as dermal absorption rates and inhalation of water whilst swimming or a comprehensive water quality data set. Children would be a sensitive subgroup and it is felt that measures to reduce exposures in this group should be considered. Further, the metals concentrations in surface water are above acceptable recreational water quality guidelines and hence management may be required once this is confirmed by more comprehensive and targeted monitoring This will be important if the potential exists for marron farms or aquaculture where the risks of metals uptake are high.
- There are still many questions about the potential for health risks. To clarify whether current concentrations are impacting on health it is recommended a comprehensive water quality monitoring program be implemented with appropriate detection limits for metals and includes testing for micro-organisms, biological pathogens, and vector-borne diseases. To ensure that exposure to metals is not a significant issue, a short term human exposure study could assist in assessing human health risks and firm up the results of the screening health risk assessment.
- If further monitoring of the water quality in the pit lakes confirms elevated mercury, we advise the Department of Water to develop a communication plan to advise users of the potential issues. As noted, the recent samples analysed in April 2010 for mercury and arsenic concentrations are below recreational water guidelines
- Respondents to the survey were concerned about the management of the pit lakes with sixty percent wanting some form of active management by the placement of facilities such as toilets. Nearly eighty percent want the lakes used for water-based recreational areas.
- Of urgent attention is the need to address management of the lakes with the provision of appropriate facilities such as toilet blocks with cleaning and rubbish bins and collection. This would reduce the risks of injury from broken glass bottles and other wastes left in the areas. Installation of toilet facilities would reduce the potential for health effects from faecal contamination.
- Hinwood, A., Heyworth, J., Tanner, H., McCullough, C., and Lund, M. (2011) Water Quality of Mine Void Pit Lakes Used for Recreation. Epidemiology 22 (1), S296 link
- Hinwood, A.; Heyworth, J.; Tanner, H. & McCullough, C. D. (2012). Recreational use of acidic pit lakes – human health considerations for post closure planning. Journal of Water Resource and Protection. 4: 1,061-1,070. link
- Hinwood, A. L.; Heyworth, J.; Tanner, H. & McCullough, C. D. (2010). Mine Voids Management Strategy (II): Review of potential health risks associated with Collie pit lakes. Department of Water Project Report MiWER/Centre for Ecosystem Management Report 2010-11, Edith Cowan University, Perth, Australia. 111pp. Unpublished report to Department of Water. PDF