The Assessment of Impacts from Mining Wastes on Water Quality and Aquatic Ecosystems Using Freshwater Macroinvertebrate Communities and Novel Bio-Assay Tests
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7th Australian Stream Management Conference - Full Paper The assessment of impacts from mining wastes on water quality and aquatic ecosystems using freshwater macroinvertebrate communities and novel bio-assay tests. 1 2 3 4 Rebecca Sullivan , Dr Ian Wright , Dr Adrian Renshaw , and Mitchell Wilks 1. School of Science and Health, University of Western Sydney, Locked Bag 1797, South PenrithDC, 1797. [email protected] 2. School of Science and Health, University of Western Sydney, Locked Bag 1797, South PenrithDC, 1797. [email protected] 3. School of Science and Health, University of Western Sydney, Locked Bag 1797, South PenrithDC, 1797. [email protected] 4. School of Science and Health, University of Western Sydney, Locked Bag 1797, South PenrithDC, 1797. [email protected] Key Points • The water quality and macroinvertebrate assemblages from two sites in the Lithgow area were strongly modified by two different types of mining (mixed metal and coal). • The extent and severity of these modifications differs from site to site. • Both sites have demonstrated a continual decline of macroinvertebrate abundance, family richness and modifications of water quality above ANZECC ecosystem protection guidelines. • Novel international bio-assays (not previously used in Australian waters) using New Zealand mudsnail (P.antipodarum) were most successful when tested in the contaminated waters of Daylight creek (mixed metal waste) and moderately successful with downstream waters of Wollangambe River (coal mine waste). Abstract The water quality and macroinvertebrate assemblages from two sites in the Lithgow area were strongly modified by two different types of mining (mixed metals and coal).The extent and severity of these modifications differ from site to site. The abandoned Sunny Corner mixed metal mine site impacted on Daylight creek significantly more than Clarence colliery on Wollangambe River. Both sites demonstrated a decline of macroinvertebrate abundance, family richness and degradation of water quality in comparison to ANZECC ecosystem protection guidelines. A novel bio-assay (not previously used in Australian) using the introduced New Zealand Mudsnail (P.antipodarum) provided a rapid indication of the mining wastewaters impact on macroinvertebrate communities. Keywords Wastewater, Mining, Lithgow, Daylight Creek, Wollangambe River, New Zealand Mudsnail, macroinvertebrates, water quality Introduction Coal and metaliferous mining generates large volumes of contaminated wastewater (Johnson 2003). Wright et. al., (2011) found that often in NSW this wastewater is disposed of directly into adjacent rivers and streams. Waste water from coal mining is often chemically characterized by elevated levels of salts (salinity), low pH (acid mine drainage) and elevated metal loads (Wright et al., 2011). Additionally due to acid mine drainage (a phenomenon often associated with mine waste) acidic wastewater reacts with the surrounding environment making soil metals bioavailable to freshwater ecosystem (Wright et al., 2011). Management of mining wastewater is a global concern. Metal pollution is persistent in the environment, can be present at levels toxic to survival of organisms and bio-accumulates throughout the food web. Chapmen (1983) found evidence to suggest that contaminated mining wastewater can impact the environment up to 20km (dependent on flow) downstream of the discharge. This is of particularly concern in high conservation geographical regions such as those in this study (Chapmen et al., 1983). Active mine sites such as Clarence Colliery, Lithgow NSW, are regulated by the NSW Environmental Protection Agency using Environmental Protection License 726 (Centennial Coal 2012). This license regulates the disposal of mine waste water including permitted volumes and pollutant concentrations to manage the impact from mining on the environment (Davies and Wright 2014). Sunny Corner’s historic mining area is an abandoned mine site (“a mine where no mining lease or title presently exists”: McKay et. al. 2012). Management of these areas falls on local, state, territory governments and sometimes land owners and/or industry on a basis of proven “significant liability” (Minerals Council Australia 2011). Potamopyrgus antipodarum the invasive New Zealand Mudsnail has previously been used in the northern hemisphere to assess the effects of salinity and mining metal pollution (Duff et. al 2003; Gust et al., 2010, Gust et. al. 2011).This species is highly invasive, tolerant of abiotic and polluted conditions and is similar in characteristics (sessile animals, that can Sullivan, R., Wright, I., Renshaw, A. & Wilks, M. (2014). The assessment of impacts from mining wastes on water quality and aquatic ecosystems using freshwater macroinvertebrate communities and novel bio-assay tests, in Vietz, G; Rutherfurd, I.D, and Hughes, R. (editors), Proceedings of the 7th Australian Stream Management Conference. Townsville, Queensland, Pages 269-276. 269 7ASM Full Paper Sullivan et.al. - Water quality and macroinvertebrate impacts of mining in LithgowCity bioaccumulate toxins in their tissues) to bivalve molluscs such as oysters and mussels which are already proven to be valuable indicators (Alonso 2008, Gust 2010, Gust 2011). Potamopyrgus antipodarum were chosen to be used as bio- monitoring species as they are common in urban streams in the Hawkesbury-Nepean catchment and the Sydney basin. These bio-assay tests are novel because they have not been used to test in Australian freshwater conditions. This study aimed to assess, using a multidisciplinary approach, the impact of mining waste discharge on freshwater ecosystems in the Marrangaroo district, Lithgow, NSW Australia. It also aimed to compare two different mining types (coal and mixed metal) in the same district area. Another aim was to assess if a novel bio-assay method currently in use in the Northern hemisphere can demonstrate the effects of these impacts on macroinvertebrates. This research is significant because its compares coal mine and metal mine waste impacts in a relatively undisturbed area. It will also fill knowledge gaps about the conditions of the area and highlight the existing need of proper management for conservation of the ecosystems. Methods Site Description Field-work was carried out on September 2013 and January 2014 in the district of rural-north Marrangaroo, a part of Lithgow City LGA (approximately 112-200km North-West of Sydney Metropolitan Area and 20km west of Lithgow). Three sample sites were studied across two waterways (Wollangambe River and Daylight Creek) and two different catchments (Upper Wollangambe River Catchment and Turon River Catchment). Two sampling sites were waterways receiving mining effluent (WD, SC Figure: 1). A third site was a reference site (WU) upstream of mining activity on Wollangambe River. A reference site for Daylight creek was omitted due to the headwaters of this creek receiving mining effluent. Figure1. A: Geographical location of sample sites in NSW. B: Wollangambe River Downstream of the mine site; C: Daylight Creek; D: Reference Site upstream of the mine Site Wollangambe River. All three sites were flowing and were typical of dry weather flow conditions. The exception is Wollangambe River downstream site (WD) as flow is increased significantly by treated effluent discharge averaging 457ML per a month (Centennial Coal 2012;2013). This treated effluent is from Centennial Coals and SK Energy Australia PTY Ltd.’s, active Clarence Colliery (Centennial Coal 2012; 2013). Daylight Creek receives effluent from a number of highly eroded old workings from the non-active Sunny Corner mining area. These contribute to the loading of a large variety of trace metals as acid drainage leaches into Daylight Creek (Haynes, Chaudhury, Buckney, & Khan, 2003) causing pollution for 20km downstream (Chapmen et al., 1983). Previous studies (Haynes, Chaudhury, Buckney, & Khan, 2003; Chapmen et al., 1983) have described Daylight Creek as an extremely polluted creek where green algae flourishes and fauna of the creek is largely non-existent. Both sites are surrounded by state forest and the upper Wollangambe River is located just outside the boundaries of The Blue Mountains National Park. Sullivan, R., Wright, I., Renshaw, A. & Wilks, M. (2014). The assessment of impacts from mining wastes on water quality and aquatic ecosystems using freshwater macroinvertebrate communities and novel bio-assay tests, in Vietz, G; Rutherfurd, I.D, and Hughes, R. (editors), Proceedings of the 7th Australian Stream Management Conference. Townsville, Queensland, Pages 269-276. 270 7ASM Full Paper Sullivan et.al. - Water quality and macroinvertebrate impacts of mining in LithgowCity Water Sample Collection and Analysis Physical sampling methods followed those of Wright & Burgin 2009 in a similar study conducted on the Grose River. Water samples were collected immediately prior to the collection of macroinvertebrates to minimise disturbance due to kick- sampling. At each site, water quality (electrical conductivity and pH) was monitored in situ at the center of the waterway using a portable calibrated field chemistry meter according to manufacturer’s instructions (TPS Aqua pH-Conductivity Meter). Replicated measurements (n = 10 at each site) of water quality samples were conducted on each sampling occasion. Upstream reference sampling was not possible at Daylight Creek due to mining activity (Sunny Corner Mining Area) occurring at the headwaters of the creek. An adjacent stream was proposed