Open Cut » Environment
This project was undertaken to address improvement in water quality of pit and recycled mine waters in the Bowen Basin and included a detailed study of issues related to the toxicity and management of blue-green algae. The work was presented in three sections.
PART A - USE OF AQUAPONICS FOR IMPROVEMENT OF DRINKING WATER QUALITY
Aquaponic units (floating pontoons containing selected plants) were installed and tested in Calverts Dam, Norwich Park Mine, as part of a collaborative research project between BMA, ACARP and CQU. These units were designed to reduce macro and micro nutrients required for the growth of blue-green algae.
Tomato, silverbeet and basil plants grew successfully in the floating pontoons, even during summer. These plants removed compounds from the water column including phosphorus and molybdenum, nutrients required for the growth of nitrogen fixing bluegreen algae.
Trace elements were analysed and compared between aquaponic plants and fruit, and between harvested aquaponic tomato fruit and purchased table-market fruit. Molybdenum was present in higher concentrations in the tomato plants than in the silverbeet. In addition, molybdenum concentrations were marginally higher in the tomato fruit than the tomato plants. Molybdenum concentration in the aquaponic tomato fruit was much higher than that in the purchased table-market fruit.
PART B - INVESTIGATION OF BLUE-GREEN ALBAL POPULATIONS IN PITWATER AND THE USE OF MIXING AS A CONTROL TECHNIQUE
This project sought to address the improvement of water quality and management of problems associated with blue-green algae and the reuse and recycling of pit and plant waters. It sought to identify, where possible, the wider water quality elements that selected for the dominance of blue-green algae at mine sites. In addition and more importantly, it sought to isolate those factors associated with toxin producing blooms and investigate mixing and other techniques available.
Blue-green algal blooms were detected in relatively clear alkaline pitwater. An algal bloom is defined as a cell concentration exceeding 15,000 cells mL-1 (Bowling 1992).
Mixing of various pitwater sources in a shallow dam can result in changing conditions within the receiving environment. Critical modification occurs in various physical and chemical variables,- in particular the turbidity and subsequently the blue-green algal species assemblage. The increased exposure of the surface layer to light and ultraviolet radiation may also facilitate toxin breakdown. This technique may prove a useful control measure with respect to C. raciborskii blooms within the Bowen basin as this toxin producing species dominates in stratified water columns of
low turbidity.
PART C - ASSESSMENT OF IMMULOGOGICAL TECHNIQUES FOR THE DETERMINATION OF HUMAN AND ANIMAL IMPACTS RESULTING FROM CONTACT WITH CONTAMINATED WATERS
The ability of cyanobacterial species to contaminate water sources is quite well documented, as is the capacity for different species/strains of these micro-organisms to produce toxins that may affect those that ingest or come in contact with these waters. As part of a larger study to address mechanisms to improve water quality of pit and recycled mine waters in the Bowen Basin, a scoping study was performed to assess the suitability of immunological assays to a) detect immunostimulatory agents present in mine water samples and b) shed light on the nature of the immune effect that was elicited by such factors on human and animal cells that may be exposed to these waters.
Findings from the application of two tetrazolium-based in-vitro assays suggest that the MTT Proliferation Assay, a colourimetric technique used to assess bioactivity in cells of humans and other animals, was successful in identifying water samples that have the capacity to potentiate immune responses. In addition, the NBT Test yielded results that confirmed that water samples collected from a variety of sites contained factors that promoted oxidative burst responses in human and bovine blood cells. The NBT Test was originally proposed since it had the potential to be modified for use in field tests. Results from this study suggest however that this test is not appropriate for such a purpose, as water samples collected from the field contain a variety of micro-organisms that render this test unsuitable for the intended application in this work.
In contrast, the MTT Assay appears to be suitable for laboratory detection of potential immune effects that may develop from contact with contaminated waters. Specifically, this study found that at least two sources of water samples require further investigation with regard to their immunostimulatory properties. Recommendations that arise from this work include further investigation of the nature of the stimulation response obtained from mine waters, together with a more detailed study of the mechanism of such responses. Information gathered by investigation of these two parameters will assist stakeholders to develop strategies to better manage the quality of water sources, particularly those that are associated with direct human contacts.