Environmental harm: s 241(1)(a) of the POEO Act
41Section 241(1)(a) requires that in imposing a penalty for the present offence, the Court is required to take into account the extent of the harm caused or likely to be caused to the environment by the commission of that offence. The expression "harm to the environment" is defined in the Dictionary to the POEO Act to include:
"any direct or indirect alteration of the environment that has the effect of degrading the environment and, without limiting the generality of the above, includes any act or omission that results in pollution".
The word "likely" has been determined to mean a real or not remote chance or possibility.
42The Defendant accepts that the commission of the present offence did cause harm to the environment and also accepts that it was likely to have caused harm to the environment. However, it is the nature and extent of that harm that needs to be addressed.
43It is accepted by both parties that there are two events that found the source of harm or likely harm to the environment in the present case. Obviously enough, the first event is the discharge of tailings across the Mine site and into Creek A in the manner earlier described. The second event is the clean-up and remediation action, appropriately but necessarily taken by the Defendant to address the tailings discharge on 20 June. The latter action involved not only the use of hand tools but the use of heavy equipment to remove the tailings that had spread across the site as well as the use of equipment in the bed of Creek A to remove the tailings that had flowed into the Creek. In undertaking the clean-up or remediation action, not only was there surface disturbance but also some trees were removed.
44I have earlier described the Mine site as being located in a semi-arid environment with low average rainfall. Creeks A and B only carried water for short periods throughout the year. It is agreed that immediately prior to 20 June 2013, Creek A had a natural looking bed-form with banks and trees in the riparian zone. However, the Creek had been subject to disturbance for more than a century from exploration and mining activities as well as grazing. At numerous locations the Creek banks were highly eroded and largely devoid of aquatic vegetation. Erosion is accepted as being a natural phenomenon in this environment.
45At the time of the incident, it is also agreed that aquatic flora in the form of macrophytes were present in that part of Creek A that is downstream of the Pybar Culvert, being the section of the Creek otherwise referred to as the diversion drain. However, the evidence does not enable me to conclude beyond reasonable doubt that at the time of the incident there was aquatic vegetation upstream of the pool at the Pybar Culvert.
46The impact upon or harm to the environment occasioned both by the tailings discharge and remediation action taken by the Defendant has been the subject of expert assessment by an eco-toxicologist, two ecologists and an environmental auditor. These four experts have prepared a joint report that forms part of Exhibit A. There is minimal disagreement among them.
47They agree that although additional sediment entered Creek A as a result of the clean-up and remediation, there was no evidence that it caused harm to aquatic fauna and that high sediment levels and erosion are a typical feature of this semi-arid environment. Historical water sampling shows high sediment levels above ANZECC Guidelines trigger values after rainfall.
48While it is accepted as a fact that some trees were removed as a result of the clean-up actions by the Defendant, the extent of harm by reason of that tree removal is, according to the experts, unquantifiable. In so saying, they identified the fact that some trees had been removed prior to the incident to accommodate a power line easement. Further, they agree that such tree removal as did occur in the course of clean-up had "negligible" impact upon aquatic biota.
49The tailings that spilled from the Tailings Line and entered Creek A contained metals at concentrations far exceeding ANZECC Guidelines trigger values. The weighted average metal concentrations in the tailings pumped through the Tailings Line at the time of the incident were 4.2 ppm cadmium, 1580 ppm copper, 230 ppm manganese and 1800 ppm zinc.
50Investigators from the Prosecutor attended the Mine site on 21 June when a number of water samples were taken. Analysis of these samples showed that the surface water in the section of Creek A into which the tailings had flowed was potentially toxic to some aquatic organisms for the following reasons:
(i)concentrations of dissolved metals, particularly zinc and cadmium, far exceeded ANZECC water quality guidelines trigger values for the protection of fresh water aquatic eco-systems at the 95% level of protection; and
(ii)pH and conductivity values were outside the ANZECC default trigger values for the protection of aquatic eco-systems in south-eastern Australia.
51The experts agree that high mineralisation could be expected in both water and soil on the Mine site before 20 June 2013, given the duration of mining activities at the site. They acknowledge, from such pre-incident data as was available, that water upstream of the area affected by the discharge of tailings into Creek A historically had concentrations of cadmium, copper and zinc above "unadjusted" ANZECC 95% protection level trigger values. While the view was expressed that high concentrations of metals in sediments in the impacted area of Creek A would be expected, no opinion could be expressed as to the extent to which those concentrations were higher than background.
52As part of the measures undertaken by the Defendant to validate the clean-up and remediation of the site, its consultants gathered a number of water samples on 19 July 2013. Having regard to test results for those samples, the experts agree that water in Creek A had returned to its pre-spill condition by 19 July.
53I have earlier described the clean-up action taken by the Defendant involving the use of an excavator and hand tools to remove the top layer of soil and vegetation from the bed of the Creek and from the areas over which the tailings had flowed before reaching that Creek. While the site disturbance caused by this action had an environmental impact, the experts accept that the removal of tailings solids effectively prevented any significant contamination of the underlying soils.
54The flow of tailings across sections of the Mine site, resulting in about 94 cubic metres of tailings entering Creek A, clearly occasioned environmental harm. Settlement of tailings and their chemical composition which exceeded water quality guidelines potentially had an immediate impact. It is the location and extent of that impact that must be addressed.
55There are two components of the Mine site environment upon which the evidence focuses. First is the environment of Creek A itself and second is the environment referred to in the evidence as the "flood plain habitat", being the physical environment, including trees, that were located in the area beside the Creek and over which the Creek water surcharged on the relatively rare occasions on which there was a flow of water in the Creek. As the Defendant submitted, to assess the actual and likely harm from the discharge of tailings, it is necessary to understand each of these receiving environments as they were at the time of the discharge of tailings.
56The semi-arid nature of the Mine site environment and the infrequency with which water flowed in Creek A is relevant when considering the impact upon that Creek. So also is the circumstance that the Mine site has been the subject of disturbance from mining for over 100 years.
57Having made the latter observation, the Defendant accepts that the disturbed or degraded state of the Mine site does not identify a circumstance that, of itself, mitigates the consequence of the tailings discharge that occurred on 20 June 2013. However, the condition and state of the receiving environment is relevant to the assessment of the extent of harm or likely harm caused by the commission of the offence (Environment Protection Authority v Orica Australia Pty Ltd (The Nitric Acid Air Lift Incident) [2014] NSWLEC 103 at [119]).
58As I have earlier recorded, apart from the pool at the Pybar Culvert, there were only small pools of water in the Creek on 20 June, being remnants of the creek flow that had occurred the previous week, and those small pools were expected to remain for only "a short time". Prior to the rainfall that occurred in the proceeding week, there had only been one other rainfall event in 2013 sufficient to cause the Creek to flow.
59It is accepted by the Prosecutor that at numerous places the banks of the Creek were highly eroded and largely devoid of aquatic vegetation (Exhibit A at [29]). Having regard to the condition of the Mine site at the time of the tailings discharge, I am not satisfied beyond reasonable doubt that there was aquatic flora in Creek A that was harmed by that discharge. So to conclude does not address the likelihood of harm, an impact to which I will turn shortly.
60I accept that the removal of some trees in the course of carrying out the clean-up of the flood plain area as a consequence of the tailings discharge is a loss that itself identifies environmental harm. The experts accept that the habitat has not recovered to its pre-offence condition, with natural re-establishment expected to take further time, possibly several years. The slow recovery of the flood plain habitat is not only a consequence of the semi-arid state of the site but also a consequence of top soil and vegetation removal that occurred when the spilled tailings were scraped and removed.
61Also relevant to a consideration of the harm to the flood plain environment is the fact that in the flood plain area in which the clean-up occurred, some trees had recently been removed in conjunction with the creation and use of an electricity easement. The reference to the long recovery time for the flood plain area is partly due to the loss of vegetation in the area affected by the easement clearing.
62As I have earlier recorded, the Prosecutor accepts that the clean-up of tailings was completed by 28 August 2013. By reason of this action, the experts accept that no contaminants from the tailings discharge remain on the flood plain or in the Creek so as to have any residual environmental impact. In short, the impact upon the flood plain area was the immediate effect upon existing ground cover and the loss of that ground cover and some trees as a consequence of the clean-up. The long term effect is in the slow recovery of vegetation in this area consequent upon the remedial action taken by the Defendant.
63It is next necessary to return to the likely and potential impacts upon Creek A. Not only are those likely impacts required to be considered by s 241(1)(a) but the potential or risk of harm must be considered when considering the objective seriousness of an offence of the present kind (Environment Protection Authority v Waste Recycling and Processing Corporation [2006] NSWLEC 419; 148 LGERA 299 at [145] - [149]).
64The critical component of Creek A for the purpose of considering likely environmental harm is the pool at Pybar Culvert. The Defendant accepts that unlike other pools that held water for only a short time following rainfall, water in the Pybar pool remained for a longer period of time. The experts agree and I accept that organisms such as micro and macro invertebrates and frogs were likely to have been present in that pool immediately prior to the tailings discharge on 20 June. As a consequence of that discharge, the experts agreed and I accept that "mortality of any aquatic fauna present in Pybar pool would have occurred due to the spill and remediation." When the area was visited in August 2014, aquatic invertebrates including diving beetles, water scavenger beetles, biting midges, aphids, water striders and stick caddis flies were collected from the area. These observations confirmed the likelihood that such species inhabited Pybar pool at the time of the tailings discharge and therefore are likely to have been harmed in the manner described by the experts.
65I have earlier identified the circumstance that the debris and vegetation at the Pybar pool largely blocked the tailings from being flushed through that pool into that section of the Creek formed by the diversion drain. To the extent to which the very fine fragment of the tailings flowed through the pool into the diversion drain, the experts agreed, and I accept, that it was "most unlikely" that any harm was caused by smothering in the diversion channel. The experts do, however, state that the concentration of zinc and cadmium in the tailings water, being at a level that was an order of magnitude higher than previous data had indicated for those minerals in creek water, was sufficiently great to have caused harm to some aquatic fauna, assuming they were present.
66When this area of the Creek was visited in August 2014, frogs were heard in the rushes that were growing in the diversion drain. While there is no evidence to support a finding that frogs were, in fact, present in the diversion drain at the time at which tailings were discharged on 20 June 2013, the observations made in 2014 identify the potential for some aquatic fauna to have been present. By reason of the elevated levels of zinc and cadmium, I am satisfied that the potential for harm in the diversion drain is to be recognised, albeit, as the experts acknowledged, that the degree of harm could not be quantified.
67In summary, there was an environmental impact upon the aquatic environment in Creek A. Having regard to the evidence that I have accepted, this impact was limited. So far as water quality was impacted, this impact was of short duration, it being accepted that pre-discharge water quality had been restored by 19 July 2012, thereby limiting the impact to about one month. There was potential for the impact to be more significant had the discharge of tailings taken place during a period of high rainfall and high biological activity.
68I accept the submission of the Defendant that the harm caused or likely to be caused to the environment by the commission of the offence was material and not trivial. Overall, I am satisfied beyond reasonable doubt that the harm is in the range of low to moderate.