Summary: Aquatic Ecotoxicology
Professor Amanda Reichelt-Brushett
Ecotoxicology is the study of how organisms respond to contaminants. It requires an understanding of the pathways of uptake of the contaminant within an organism’s body, exposure concentrations, bioavailability and speciation, and the behaviour of contaminates in the environment over time.
Key information that is required to conduct a proper aquatic ecotoxicology assessment of this development proposal and that is missing from the EIS includes:
- A number of newly discovered species have been recorded during the fauna and flora biological surveys; their response to increased contaminants is not known and cannot be predicted.
It is unknown what the aquatic toxicity is for the chemicals used in the floatation reagent and frothing agents. Therefore, it is not possible to determine the impacts of these chemicals on the aquatic environment. More studies are required to ensure these chemicals are safe for use, or to determine required dilution methods.
The EIS focusses on the large construction components (i.e. mine, dam etc.) but fails to examine the impacts of multiple smaller scale projects that could have significant impacts on the environment. For example, 5 major and 16 smaller bridges and airport and road construction.
ISF Water Quality: The water contained in the ISF will be treated and discharged to the downstream catchment via the hydroelectric system. The EIS assumes “suitable water quality” for the water discharged into the downstream catchment system but this does not appropriately consider the risks if water quality does not meet appropriate standards. It is of concern that:
a) The treatment process for this water is not described in the EIS, and therefore can not be evaluated for adequacy or potential adverse impacts.
b) There appears to be no process in place to respond if the water quality is compromised or contaminated during operations.
c) The fact that fine particles will remain suspended in the ISF water column, potentially accumulating contaminants before release and thus transporting contamination downstream has not been adequately considered in the EIS.
This risk requires further investigation to gain a better understanding of contaminant composition and organism responses and to design adequate protocols to ensure the aquatic environment is not compromised. This investigation should be conducted prior to any approval of this project.
Overflow Water at Vanimo Ocean Port: How the treatment and disposal of the overflow water into Vanimo Ocean Port will be conduced is unclear. Appendix 12b states that mechanical or chemical treatment will be employed to ensure dissolved copper (Cu) concentrations meet required guidelines. However, these guidelines are based on a single contaminant, not the multiple contaminants that would be likely to be contained in this effluent, nor the interaction between these contaminants. In addition, the discharged waters will be freshwater that is being discharged into a marine environment at 30°C and a flow rate of 55L/s at a depth of 13m. This freshwater influx has the potential to negatively impact corals and other benthic communities. This potential impact has not been considered.
Ok Binai catchment waste dump: the EIS lacks detail on how this waste dump will be managed. This waste dump will be comprised of the non-acid forming rock (approx. 22%) and organic waste from the pre-strip of the open pit. Manganese, zinc, nickel, cobalt, chromium and cadmium were shown to be above soil background levels in the core samples. Further information is required to understand the risk of contamination of these elements at this site.
325 km pipeline transporting concentrate: this pipeline is long and traverses difficult terrain, as well as ecologically important wetlands and habitats. There is significant risk of rupture or leakage along this pipeline, particularly given the risk of earthquakes or landslides due to the average rainfall of over 8m per year. How these risks have been considered, if at all, is not clear.
Soil Dumps: these sites receive 8m of rainfall per year. As such, they will need careful management to avoid negative impacts from significant sediment loading in the waterways. This does not appear to be addressed in the EIS.
Vanimo Ocean Port reclamation: minimising marine environmental impacts during the bay reclamation process at Vanimo Ocean Port does not seem to have been addressed, nor has the risk of introduced and invasive species from enhanced shipping activity.