Statutory considerations
14 Section 241 of the POEO Act prescribes matters which, so far as they are of relevance, must be considered in imposing a penalty for the offence. I deal with each in turn.
15 (a) the extent of the harm caused or likely to be caused to the environment by the commission of the offence
The prosecutor submitted that there are two ways in which harm was caused to the environment or was likely to be caused by the commission of the offence. The first is the impact of the pH value of the wastewater that was discharged, and the second is the impact from concrete sediments that were likely to be contained in that wastewater.
16 Dealing first with the pH value, samples of the discharge were taken. The pH of the water discharging from the stormwater outlet into the Alexandra Canal was 12.3. The water in the channel leading to the stormwater pit also had a pH of 12.3, and the water channel adjacent to the washout pits had a pH of 12.1. A sample of the water in the Alexandra Canal in the vicinity of the stormwater outlet showed a pH of 8.5.
17 The term "water pollution" is defined in the Dictionary to the POEO Act to include, in par (c), placing in waters any matter that is of a prescribed nature, description or class. Clause 52 of the Protection of the Environment Operations (General) Regulation 1998 provides that the matter described in sch 3 is prescribed for the purposes of par (c). Item 17 on the list of matters described in sch 3 is "[a]ny matter that has a pH value of less than 6.5 or more than 8.5".
18 It is agreed that approximately 600 litres of water discharged into the Alexandra Canal between 4 pm and 6:30 pm on the day of the incident. The prosecutor submitted that, as it is agreed that the discharge continued until 8:30 pm, it is likely that the total discharge from the site was closer to 1000 litres.
19 Evidence as to the harm or likely harm caused by the discharge was given by Mr M J Root, an environmental scientist employed by the prosecutor. His opinion was that the pH of the wastewater discharged into the Alexandra Canal was high, and had the potential to adversely affect the aquatic communities in it. However, it was unlikely that there was actual harm from the pH levels because, as demonstrated by the pH value of 8.5 in waters near the stormwater outlet, the tidal water in the Alexandra Canal was likely to have been sufficient to dilute and mitigate the effect of the high pH wastewater.
20 As to the impact from concrete sediments likely to be contained in the wastewater discharge, it is an agreed fact that, on the day after the incident, a plume of sediment estimated at around 10 metres long and extending around 5 metres across the Alexandra Canal was visible from its shore.
21 On 7 June 2001, nine core samples of the sediment on the floor of the Alexandra Canal were taken from locations adjacent to the stormwater outlet and upstream and downstream of the site. All were analysed and reported on by Dr J A Cattle, a soil chemist employed by the prosecutor. All samples contained elements which are major constituents of cement. However, Dr Cattle concluded that only one of the samples (taken from a location adjacent to the stormwater outlet) had similar characteristics to the sample of solid material from the discharge point into the Alexandra Canal, and she said that this suggested a common origin. Three other samples which she analysed had similar characteristics, but to a lesser degree. The remainder did not have similar characteristics.
22 The other piece of relevant evidence was a report prepared for the defendant by Johnstone Environmental Technology Pty Ltd. The opinion expressed in that report was that a white deposit of material on the floor of the Alexandra Canal was likely to be cement, but it had built up over a period of time and was not the product of one event, but rather of long term accretion.
23 Given that a plume of sediment had been observed on the day following the incident, and having regard to the evidence I have outlined, I find that sediments likely to contain cement material were contained in the wastewater that discharged from the site.
24 Mr Root's opinion was that, during the period that the sediment plume was present in the water in the Alexandra Canal, the sediment contained in the wastewater discharge was likely to have smothered any small sessile or sedentary macroinvertebrates that were living in the area directly affected by the plume, and there was a possibility that it rendered that area unsuitable for re-colonisation by aquatic species until it was dissipated by the tides, currents or other actions. However, there is some doubt that any aquatic species existed in the Alexandra Canal at the time of the discharge. Mr Root thought there were, although characterised by low diversity and being hardy, pollution tolerant or transient species. On the other hand, Mr W S Rooney, whose area of expertise is aquatic ecology and water quality, was of the opinion that little if any benthic macroinvertebrate life was present in the sediments in the Alexandra Canal, and virtually nothing would live in the sediment deposits adjacent to the stormwater outlet. He thought that, if there were any fish present at the time of the incident, they could have avoided the plume, and, furthermore, the chemical reaction of the slurry with seawater would render it benign almost immediately.
25 From all this evidence, I find that no actual harm to the environment was caused by the commission of the offence, and that, although there was a likelihood of harm, it was, in all the circumstances of the incident and its impact, of a minor degree.
26 (b) the practical measures that may be taken to prevent, control, abate or mitigate that harm
As set out in par 13, I have found, on the balance of probabilities, that the deposit of concrete material in the eastern end of the dish drain was a deliberate act and not a consequence of 'poor housekeeping'. Nevertheless, it is significant that the discharge commenced at a time after 3pm when the defendant's maintenance personnel had left the site. Mr Farah stated, in the incident report prepared by him on 22 June 2001, that he believed the yardman to have "… left the wash out pit system in such a state that it would have adequately coped with the activities of the night shift". Despite the comfort the defendant derived from this belief, the fact is that there was no employee available to monitor the operations on the site to ensure there was no risk of harm to the environment. The practical measure which the defendant could have taken was to ensure that such an employee was on site and available during the 24 hour operation of the plant to monitor and supervise the operation of the plant. Such monitoring and supervision would have been likely to have prevented the discharge of the wastewater. Whilst there is no evidence to establish that such a procedure could have prevented the deposit of concrete in the eastern end of the dish drain, I am prepared to accept that a yardman or supervisor could have acted to control the damming of the wastewater in the dish drain and to avoid or mitigate its discharge into the stormwater pit.
27 (c) the extent to which the person who committed the offence could reasonably have foreseen the harm caused or likely to be caused to the environment by the commission of the offence
The prosecutor relied upon three matters to establish that the defendant could reasonably have foreseen the harm caused or likely to be caused to the environment by the discharge of wastewater with a high pH level and containing concrete sediment. They were as follows:
i. The potential for harm was identified by the defendant in several of its "plant daily reports". For example, in the report for 5 March 2001, the defendant stated that "[d]esign of washout pit. Amount of slurry build up may lead to a environmental problem" and in the report of 6 March 2001, it stated "[p]it design. Washout pits leading to overflow stormwater";
ii. Tendered in evidence was a copy of a document created by the defendant in January or February 2001 entitled "Summary of Environmental Issues for Metro Sydney up to 2005". Under the heading "water", and in respect of the site (as distinct from other properties of the defendant referred to in the document) it stated:
Issue -
*Severe ponding near storm water outlet. High risk of discharge to Alexandria Canal. (R)
Solution -
*Rectify levels and modify recycle water system
Est. Costs -
*$50K - budgeted 01/02
The legend to the document stated: "Red - High risk requiring immediate attention". I infer that (R) refers to "Red".
iii. As I have already mentioned in par 10(iv), Mr Kolic had observed wastewater flowing into the stormwater pit "a couple of times".
28 I am prepared to accept the matters set out in par 27(i) and (ii) as establishing that the defendant had foreseen that water was likely to discharge to the Alexandra Canal, and that it would have an environment consequence.
29 (d) the extent to which the person who committed the offence had control over the causes that gave rise to the offence
Despite my finding that the concrete material in the eastern end of the dish drain was placed there by deliberate act, I find that the defendant had full control of how the plant was operated and managed on the site. It was within its control to monitor and supervise the operation of the washout pits, and it did not do so at the relevant time.