Water sampling – Turon River near Sunny Corner, 2023 to 2025
We have completed a surface water and sediment sampling program in the creeks and rivers downstream of the former Sunny Corner mine site.
The purpose of the sampling program was to assess whether groundwater, discharging from the former mine site, is likely to have an impact on the health of recreational users, including campers, downstream of Sunny Corner and to provide general commentary on the potential impacts on aquatic ecosystem health.
Snapshot of sampling results and guidance
Recreational
- Daylight Creek: not suitable for recreational uses, such as swimming or wading, because it is acidic and has high concentrations of some metals
- The camping grounds in the Turon National Park and the private camping ground along the Williwa Creek, are suitable for recreational use.
Acquatic ecosystems
- Daylight Creek: potential risks to aquatic animals and plants due to elevated dissolved metals concentrations
The influence of the former Sunny Corner mine site on the quality of downstream waters diminishes with distance.
Sunny Corner is an historic silver, lead and zinc mining site located between Lithgow and Bathurst, 180 km west of Sydney, NSW.
Mining commenced at Sunny Corner in 1875 and continued until 1949. During mining and post closure acid mine drainage has discharged into Daylight Creek.
Further information on the history of mining at Sunny Corner can be found in the book written by Vicki Powys and found at Sunny Corner: A silver town of the 1880s.
During mining and post closure acid mine drainage has discharged into the nearby Daylight Creek. Acid mine drainage occurs when mining activities expose rocks, containing sulphides, to air and water which in turn leads to the formation of sulphuric acid which can lead to very low pH (i.e. acidic) runoff or drainage. In addition to low pH water, typical contaminants associated with former mine sites such as Sunny Corner include arsenic, cadmium, copper, lead and zinc.
The Department of Regional NSW has invested $ 1.2 million on remediation work at Sunny Corner which has included earthworks to reduce the generation of acid mine discharge from the historical mining site.
Sampling
Sample locations
We undertook a survey of the Turon River and its tributaries downstream of the Sunny Corner mine site in 2023 to identify suitable sampling locations. Sampling sites were biased towards areas used for camping and where there was safe access for staff to collect water samples. Seven locations were selected which encompassed creeks close to the former Sunny Corner Mine, a private camping area on Williwa Creek and 3 camping areas within the Turon National Park on the Turon River.
Water samples have been collected from three monitoring rounds to date (spring 2023 and autumn and winter 2024) from the following sites downstream of the former mine:
| Point Number | Location | Distance from Sunny Corner mine | Latitude | Longitude |
|---|---|---|---|---|
| 1 | Upper Daylight Creek | 1.437 km | -33.358361 | 149.897028 |
| 2 | Lower Daylight Creek | 5.810 km | -33.336528 | 149.926028 |
| 3 | Williwa Creek (private campground) | 23.414 km | -33.246131 | 149.973733 |
| 4 | Jews Creek | (NA – background sample location) | -33.234169 | 149.980942 |
| 5 | Woolshed Flat Campground | 35.371 km | -33.200499 | 149.958311 |
| 6 | The Diggings Campground | 38.260 km | -33.183816 | 149.954221 |
| 7 | Turon River Campground | 39.696 km | -33.189694 | 149.946861 |
The map below shows the sampling locations.
Sampling approach
Water and surficial sediment samples were collected from each of the 7 sampling locations across multiple seasons to provide an indication of whether there are any seasonal influences on water and sediment quality. Samples were collected on the following dates:
- Spring 2023 – Water samples only were collected on 5 September 2023
- Autumn 2024 – Water and sediment samples collected on 5 and 6 March 2024
- Winter 2024 – Water and sediment samples collected on 7 and 8 August 2024
- Spring 2024 – Water and sediment samples collected on 5 November 2024
- Summer 2024/25 – Water and sediment samples collected on 17 February 2025.
Water samples were collected from within the top 15–30 cm of the creeks and rivers in laboratory prepared sample containers. Sediment samples were collected from surficial sediments (top 0–10 cm) within the creeks and rivers (i.e. not from the adjacent banks).
A water quality meter was utilised during the sampling process to measure key field water quality parameters including pH, electrical conductivity (EC), dissolved oxygen, temperature, and turbidity.
Samples were sent to the NSW Environmental Forensics laboratory in Lidcombe and analysed for a suite of metals, nutrients, miscellaneous inorganic chemicals and water quality parameters (pH and EC).
Results
Field and laboratory results are evaluated against the relevant Australian guideline values for water and sediment quality. Guideline values represent the level of a pollutant where there is a low risk to the environmental value (e.g. recreational uses; aquatic ecosystems).
| Item | Guideline | Action | Results |
|---|---|---|---|
| Recreational exposure | National Health and Medical Research Council’s (NHMRC) Guidelines for Managing Risks in Recreational Water (2008) |
| Table 1 |
| Potential risks to aquatic ecosystems | Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZG 2018; ANZECC, 2000) |
| Table 2 |
| Sediment sampling | sediment quality guideline values set out in ANZG (2018) |
| Table 3 |
General observations
Samples were collected over all 4 seasons including 2 sampling rounds in spring. No significant differences were observed in the size of the flow within the creeks and rivers at each location from season to season.
Sediment samples were often hard to collect on account of the rocky creek and river beds and relatively limited amounts of readily available surficial sediment.
Physicochemical
Water at all 7 locations was typically clear with turbidity below 10 NTU (nephelometric testing units) across all seasons. Water temperatures were significantly cooler in winter compared with the warmer months with the difference typically being over 10°C.
Electrical conductivity (EC), a de facto measurement of the concentration of ions and salts (or ‘saltiness’) in water, was measured in the field. EC is reported in micro Siemens/cm (µS/cm).
| Point | Location | Range (µS/cm) |
|---|---|---|
| 1, 2 | 2 locations closest to Sunny Corner | 170–440 |
| 3 | Williwa Creek 23km downstream of Sunny Corner | 310–510 |
| 4 | Jews Creek | 1,100–1,500 |
| 5, 6, 7 | 3 campgrounds on Turon River | 530–970 |
Notes
- Point 4, Jews Creek: not influenced by the former Sunny Corner mine site
- Points 5, 6 and 7: influenced by the higher concentrations from Jews Creek.
There is no guideline for recreational users, however the Australian and New Zealand Guidelines for Fresh and Marine Water Quality, 2000 provides a default value for EC in ‘upland rivers’ of 30 to 350 µS/cm.
Measurements of pH in the field were typically within or close to the recreational guideline range of 6.5 to 8.5. The exception was pH measurements made in Upper Daylight Creek which ranged from 3.7 to 6.0 at Point 1 and 5.0 to 6.5 at Point 2.
Metals
There were exceedances of the recreational guideline values at Points 1 and 2 (the sites closest to the legacy Sunny Corner mine), where aluminium, lead, nickel and zinc concentrations were consistently above these guideline values (Table 2 of guidelines). There were no exceedances of these guideline values at the other monitoring sites including the campground sites.
Dissolved concentrations of aluminium, cadmium, cobalt, copper, lead, nickel, silver and zinc were consistently above the relevant aquatic ecosystem health guideline values at Point 1 (as summarised in Table 3 of guidelines). These concentrations and the number of exceedances of these guideline values decreased substantially downstream of Point 1 (Upper Daylight Creek). For example
- the mean dissolved aluminium concentration was 4.5 mg/L at Point 1, well above the relevant guideline value (0.0008 mg/L where pH<6.5; 0.055 mg/L where pH>6.5), whereas concentrations were below the laboratory limit of detection or the guideline value in all samples from other sites (Table 3).
- The mean dissolved cadmium concentration decreased from 0.095 mg/L at Point 1 to 0.0006 mg/L at Point 3 and concentrations were below the aquatic ecosystems guideline value (0.002 mg/L) in all samples from points 4, 5, 6 and 7 (Table 3).
Similar decreasing concentrations were observed for dissolved cobalt, copper, lead, nickel, silver and zinc, although dissolved copper concentrations remained above the aquatic ecosystems guideline value in two samples from Point 6 and zinc concentrations in all samples from the 3 Turon River sites (Points 5, 6 and 7). There were no exceedances of metals guideline values in samples from Jews Creek.
Analytical results for selected metals from the sediment samples collected at the seven monitoring locations are summarised in Table 4 of the guidelines. Generally, concentrations of metals in sediments also followed a decreasing trend, with the highest concentrations and greatest number of exceedances of the guideline values at Points 1 and decreasing substantially with distance downstream. Some samples from Point 3 (Williwa Creek) contained concentrations of arsenic, cadmium and lead in excess of the default guideline values, and zinc concentrations above the upper sediment guideline value. Most sediment samples from the 3 camping site locations in the Turon National Park (Points 5, 6 and 7) contained zinc concentrations greater than the default guideline value and the concentrations of 2 samples were above the upper guideline value. There were no exceedances in the sediment samples collected from within Jews Creek.
Findings
Recreational contact
Daylight Creek, near the legacy Sunny Corner Mine, is not suitable for recreational uses, such as swimming or wading, because it is acidic and has high concentrations of some metals.
The camping grounds in the Turon National Park and the private camping ground along the Williwa Creek, are suitable for recreational use. The pH is generally in the neutral range and metals concentrations are consistently below guideline values further downstream in the Turon River at these camping grounds. As such, these pollutants do not pose risks to swimmers or other recreational users at these downstream sites.
The EPA will share the results from this monitoring program with the NSW Department of Primary Industries and Regional Development and recommend that historical signs warning of the hazards in Daylight Creek be reinstated.
Aquatic ecosystems
The elevated dissolved metals concentrations in Daylight Creek indicate potential risks to aquatic animals and plants. These results are consistent with, although lower than, those reported in published literature (e.g. Hayes et al. 2003) for the Sunny Corner mine.
The influence of the former Sunny Corner mine site on the quality of downstream waters diminishes with distance as is evident from the zinc concentrations at the Williwa Creek and Turon River monitoring sites where there is an order of magnitude drop from Daylight Creek to Williwa Creek and again to the Turon River locations.
Sediment
The highest concentrations and greatest number of exceedences of sediment quality guideline values were at Point 1 (Upper Daylight Creek), with concentrations generally decreasing with distance downstream. Some metals were still above the sediment guideline values in samples collected at Williwa Creek (Point 4), approximately 23 km downstream of Sunny Corner. Zinc remained above the sediment guideline value in most samples from the 3 Turon River camping ground sites (Points 5, 6 and 7) approximately 38 km downstream of the former mine.
The former Sunny Corner mine site, the source of elevated pH in surface waters and heavy metals within large stretches of receiving waters, is progressively being improved. There are ongoing works proposed by the Legacy Mines Program run by the NSW Department of Primary Industries and Regional Development.
Private industry is playing a part in the rehabilitation of sites like Sunny Corner with, for example, a proposed project by Broula King Enterprises to remove the former slag and mullock heaps at Sunny Corner and ultimately rehabilitate these areas of the site.