(b) an annual compliance audit to check that Cleary Bros has properly implemented and is complying with its EMS including undertaking appropriate site specific risk assessments. The first audit is due to be carried out during June 2006.
122 Ms Sage is in the process of updating the landfill EMP to incorporate the recent infrastructure changes that have occurred at the landfill in consultation with Cleary Bros. A revised landfill EMP will be completed by August 2006.
Environmental impact of pollution incident
123 Dr Pablo, an ecotoxicologist called by the prosecutor, and Mr Anink, an aquatic ecologist called by the defendant, provided affidavit evidence on the environmental harm caused by the pollution of Mill Creek.
124 Dr Pablo first described the environment of Mill Creek in the following terms:
"Mill Creek generally consists of a series of small to large ponds separated by shallow areas lined with bedrocks and occasionally with soft sediment. The volume of water in the creek depended on the size and depth of the ponds, with water flowing extremely slowly between ponds through crevices on rocks or over sediments in riffle areas. During dry weather when flows are extremely low, the creek would have a high capacity for storing in-channel water. The bottom and sides of the creek is mainly soft silty sediment, which is a good habitat for macroinvertebrate fauna. The banks of the creek had riparian vegetation consisting of various shrubs, trees and patchy areas covered with grass. During our site visit, we heard the croaking of frogs along the length of Mill Creek we visited, however we observed numerous mosquito fish ( Gumbusia ) with size up to 2 cm, swimming around only in the downstream portion of Mill Creek that we visited."
125 Dr Pablo sampled and analysed surface sediments along the edge of the bank of the creek just below the water surface to identify the macro invertebrate fauna to family level. Dr Pablo summarised her analysis as follows:
"All of these sediment samples collected during my site visit were analysed and showed the presence of moderately sensitive insect species such as mayflies, dragonflies, caddisflies, damselflies, crane flies, midge fly larvae; crustacean species, copepods and ostracods; and an introduced mollusc species snail. The samples also showed a relatively huge number of tolerant worm species and chironomid non-biting midges, which can better withstand the presence of pollutants. Overall, the species composition indicates that the creek is a typical urban creek perhaps leaning more towards a moderately disturbed system. "
126 Dr Pablo then discussed the pollutant, namely the leachate from the landfill:
"Leachate is that liquid formed within a landfill site that is comprised of the liquids that enter the site (including rainwater) and the material that is leached from the wastes as the infiltrating liquids percolate downwards through the waste. When leachate is produced, the liquid picks up dissolved materials from the decomposing wastes. Generally leachate has a high Biochemical Oxygen Demand (BOD)* and high concentrations of organic carbon, nitrogen (N), chloride (C1-), iron (Fe), manganese (Mn) and phenols. Many other chemicals may be present including pesticides, solvents and heavy metals. Depending on characteristics of the landfill, the wastes it contains, and the stages in the decomposition process occurring within the wastes, the leachate composition will vary with waste constituents and their solubilities, and leachate quality will change with time. Hence the leachate may be relatively harmless to extremely toxic. [*BOD measures the oxygen utilised during a specified incubation period for the biochemical degradation of organics and oxidation of inorganic materials.]"
127 Dr Pablo carried out a chemical analysis of the leachate material spilt into Mill Creek during the incident by the defendant and by the prosecutor. Both sets of samples were collected on 10 January 2005.
128 The defendant's sample was collected from the leachate collection dam while the EPA sample was collected from the bunded area of leachate storage tanks. Some differences in chemical analysis results could be expected. Dr Pablo summarised the results as follows:
"30. Nitrogen-containing compounds. Both WSN and EPA measured high ammonia (NH3) concentration of approximately 1400 mg/L in the leachate, and low nitrite/nitrates (NOx). The high Total Kjeldahl Nitrogen (TKN) measured by EPA is consistent with the high nitrogen levels in ammonia. High ammonia levels are consistent with a progressing decomposition of leachate components in an environment of diminishing levels of oxygen. High levels of ammonia contaminating the waterway is a concern because it has adverse effects on aquatic life.
31. Phosphorus and sulfur-containing compounds . WSN measured 250 mg/L sulphate while EPA measured 12 mg/L total phosphorus in the respective samples. These values are typical in leachate materials.
32. BOD and Chemical Oxygen Demand (COD) . There is a large discrepancy in BOD measured by WSN and EPA in their respective samples. WSN measured relatively high BOD of 4100 mg/L of leachate from the dam, while EPA measures 250 mg/L BOD and 2500 mg/L COD in leachate from bunded area around the storage tanks. Leachate materials are expected to have high oxygen demand primarily because the biochemical breakdown of organic and some inorganic materials requires oxygen O2. This was consistently observed in our laboratory when the test solutions prepared from ecotoxicity tests exhibited huge drop in dissolved O2 over 48 hours (see paragraph 52 below). The discrepancy in measured BOD by WSN and EPA may be due to the differences in the source of the samples and their handling until the time of analysis.
33. Metals and conductivity . WSN measured relatively high concentrations of metals calcium Ca, magnesium Mg, sodium Na and potassium K (Table 1), which are soluable and mobile metals easily picked up by the percolating liquid through waste materials. These metals are mainly responsible for the high conductivity (1800 µS/cm, measured by EPA) of the leachate material. The EPA conducted tests on its sample to detect any heavy metals which, if present in the waterway in higher than the ANZECC trigger values, may be of concern. Except for iron at 5.3 mg/L, these metals measured below one mg/L and so they might not be of concern.
34. Organics . Phenols are a common constituent of leachate materials. WSN measured 4.3 mg/L total phenolics in their sample, while EPA identified a trace of bisphenol from its sample. As with the BOD, differences in phenols measured by WSN and EPA could be due to differences in their source of sample. Bis-2-ethylhexyl phthalate was identified in the EPA sample, however this is most likely residual from the plasticizer in plastic bottles used for sampling. Other organics detected by EPA were the last 3 chemicals (all organic acids) under column 3 in Table 1. Organic acids are common intermediate products of the aerobic degradation by hydrolysis of carbohydrates or deamination of proteins in wastes. These organic acids continue to decompose to carbon dioxide, hydrogen, ammonia and other simpler compounds."
129 Dr Pablo noted that of these leachate components:
"…the high concentration of ammonia is clearly the principle chemical-of-concern affecting aquatic life. The high oxygen demand (BOD) of the sample would also be of concern because the leachate components, even upon entering Mill Creek, would continue to decompose required dissolved oxygen from water. This had the potential to deplete O2 levels in Mill Creek water. The high conductivity of the leachate material also had the potential to adversely affect aquatic life."
130 Water samples were collected along Mill Creek. Dr Pablo analysed the results obtained from the samples and concluded as follows:
"37. Where the overflowed leachate entered Mill Creek at the top main pond (site 5), the ammonia concentration, BOD, COD and conductivity were reduced to ~60% of their levels in the raw leachate material. This indicates that during sampling on 10 January 2005, the liquid at the discharge point in the top main pond was dominated by leachate material. In my opinion, the volume of water in Mill Creek during that mid-part of summer would have been low, so that dilution of the overflowed leachate was poor and the flow of liquid through Mill Creek depended on how much leachate spilt into the creek.
…
39. The ammonia concentration, BOD and conductivity of water decreased with increasing distance going downstream from the discharge point. This is consistent with the Mill Creek being contaminated with spilt leachate material from the bunded storage tanks area up to at least site 11, with ammonia levels ranging from 820 to 17 mg/L, BOD of 170 to 6 mg/L and conductivity of 12000 to 770 µS/cm. I note that this is consistent with visual observations made by Ms Burgett (paragraphs 20 to 21 of the affidavit Jane Burgett of 16 December 2005) who attended the incident on 10 January 2006. At the next site, being site 13, ammonia was slightly high at 3.5 mg/L, while BOD and conductivity were typical background levels.
…
41. Towards the upstream direction of Mill Creek from the discharge point, the ammonia levels, BOD and conductivity of waters were significantly lower than at the discharge point. This indicates that there was no source of leachate material above the discharge point from the bunded area of storage tanks. I note that what was called site 6 by DEC staff is not well defined with respect to distance from the discharge point or the main pond; it is likely that it is close to the licensed monitoring point MC1 by WSN. At the headwaters of Mill Creek (site 7), ammonia level, BOD and conductivity were similar to those at MC3 (site 1), the most downstream site inspected by DEC staff on 10 January 2005. I consider these levels typical background levels, upon which I compare levels at other sites.
42. The progress reports that WSN submitted to NSW EPA showed that the ammonia and conductivity measured at the monitoring point MC1 were extremely high (499-716 mg/L ammonia; 7752-8950 µS/cm) for at lease 2 days following the incident…For 4 weeks from 18 January 2005, ammonia significantly decreased from 12.3 to 3.3 mg/L.
43. At MC3, the ammonia and conductivity were at background levels following the incident on 10 January 2005 to 15 February 2005.
45. I note that the measured results for ammonia on 10 January 2005 in Mill Creek (820 mg/L to 17 mg/L) are approximately 328 to 7 times the licence limit for ammonia and the highest concentration from the ANZECC (2000) guideline for ammonia. Similarly, for conductivity, the measured results (12000 to 770 µg/L) are 8 to 0.5 times the licence limit and the 1992 ANZECC guideline."
131 Dr Pablo conducted toxicity tests whereby organisms were exposed to a range of concentrations of samples containing the chemical components. The results were as follows:
"50. The results of C. dubia and V. fischeri toxicity tests agree in showing the following:
(i) The sample from the leachate storage tanks (sample 4.2) was very toxic to the test organisms, confirming the toxic nature of the leachate that overflowed into Mill Creek.
(ii) The samples taken at Mill Creek (samples 3.2, 12.2, 1) exhibited decreasing toxicity as the sample was collected father downstream from the discharge point. This is consistent with the toxicity being due to leachate material spilt into the Creek. The most downstream sample (site 1), collected from MC3, did not exhibit toxicity.
(iii) The sample taken at the headwaters of Mill Creek (sample 7) was not toxic to the test organisms, indicating the absence of source of toxic material above the discharge point."
132 Dr Pablo also noted the effect of dissolved oxygen:
"52. …One of the parameters measured was DO which I note from test reports were low at the start of tests, being 72% and 68% saturation respectively for 30% dilution of leachate from inside the bund (site 4) and 50% dilution of Mill Creek water sample collected downstream of discharge point (site 3). Further, I note that the DO decreased significantly over the 48 hours of C . dubia tests. This is a clear indication of the presence of leachate chemicals in solution whose biodegradation utilised oxygen in solution. In my opinion, when leachate material is spilt into Mill Creek, a similar consumption of oxygen from water would occur to support the aerobic decomposition of leachate components. In effect, depending on the volume of overflowed leachate and available oxygen in water, the DO in Mill Creek waters would have reduced significantly."
133 Having regard to these results, Dr Pablo drew the following conclusions in relation to the environmental harm caused by the pollution incident:
"53. The spill of leachate material from WSN storage tanks into Mill Creek caused the increase in ammonia concentration, conductivity and BOD in at least 800-metre length of the Creek downstream of the discharge point immediately following the incident on 10 January 2005. At MC1, ammonia was extremely high for the next 2-7 days, then decreased the following 4 weeks but still exceeding the ANZECC (2000) WQG. Below I address the harm caused by ammonia, conductivity and decreased DO in water.
54. Ammonia . Ammonia is a non-persistent and non-culmulative toxicant to aquatic life. It consists of 2 chemical forms that are in equilibrium in water: the un-ionised ammonia, NH3, and the ionised ammonia, NH4+. Typically the concentration is expressed as 'total NH3-N' which is the sum of concentrations of the two forms expressed as mass of nitrogen N. Of the 2 forms of ammonia, the un-ionised NH3 is the principal toxic form because it is able to cross epithelial membranes of aquatic organisms more readily that NH4+. The toxicity of ammonia is dependant on pH such that at higher pH, the un-ionised NH3 contributes greater proportion to the toxicity and the ionised NH4+ is more important at lower pH. Ammonia is acutely toxic to freshwater organisms at concentrations ranging from 0.5 to 23 mg/L for invertebrate species and from 0.88 to 4.6 mg/L for fish species. Generally, the sensitivity to ammonia increases in the order: phytoplankton < invertebrates < fish. Acute toxicity to fish and invertebrates may cause loss of equilibrium, hyperexcitability; increased breathing rate, cardiac output and oxygen output; and in extreme cases, convulsions, coma and death. Chronic effect include a reduction in breathing process, reduction in growth rate and morphological development, and pathological changes in gill, liver and kidney tissue.
55. The ammonia measured in Mill Creek of 500-820 mg/L in the main pond for 2 to 7 days following the incident on 10 January 2005, have severe impact on aquatic life in the area. These concentrations were sufficient to cause death of most invertebrates, including crustaceans like crayfish in the main pond and the organisims identified in the sediments during my site visit. The dead crayfish and other invertebrates observed at the main pond of Mill Creek on the second and third days after the incident (see paragraph 14(ii) and 14(iii)) would have been due to the high ammonia in waters. If mosquito fish Gambusia and tadpoles were present in the main pond during the incident, they would have very likely died as well.
56. The high ammonia in the main pond over a period of 2-7 days would consequently have serious impact on the ecosystem structure and function. As for frogs if present, they would have likely escaped the polluted water and gone either upstream or far downstream to find unpolluted habitat.
57. In the next approximately 800-metre length of the creek (up to what DEC staff call site 11), the toxicity test results and ammonia levels measured on 10 January 2005, indicate that invertebrates and micro-organisms would have been adversely affected by the presence of ammonia in the water. The few hours following the incident would still have high ammonia, and would have acute toxicity to both moderately-sensitive and sensitive invertebrates. With time, the ammonia in this part of the creek would have gradually decreased because of the non-persistent characteristic of ammonia, hence there would be decreasing impact to aquatic life.
58. Conductivity . Conductivity increases in water is brought about by increase in ion concentrations such as metals Na, K, Mg, Ca (see paragraph 33) and negative ions such as chloride. High conductivity directly affects the osmotic regulation by aquatic organisms. It disrupts the salt balance across cell membranes, resulting in intracellular chemicals to increase concentration. Consequently, it has adverse implications on the physiological processes of the organism. Invertebrates, particularly those in early stages in the life cycle, are among the most sensitive species to increased conductivity, with adverse effects apparent for some species to as low as 1500 mg/L dissolved salts (~3000 µS/cm) [Hart BT, Lake PS, Webb JA and Grace MR (2003) Ecological risk to aquatic systems from salinity increases. Australian Journal of Botany, 51, 689-702]. The high conductivity of water at Mill Creek main pond for 2 to 7 days following the incident on 10 January 2005 (7700 - 12000 µS/cm), would have affected the invertebrates present, including those mentioned in paragraph 20. In addition to ammonia, high conductivity would have contributed to the death of crayfish and invertebrates in the main pond.
59. Reduced DO . Low DO concentrations in water can result in adverse effects on many aquatic organisms which depend upon oxygen for their efficient functioning. There are few data on the oxygen concentration tolerance range of Australian freshwater invertebrate species, however literature suggests that DL below 5 mg/L are stressful to many species and should be prevented where possible. As mentioned in paragraph 52, waters at Mill Creek which have been contaminated with the spilt leachate material would have the DO reduced significantly due to high O2 demand of the leachate decomposition during the first few days following the incident. Particular in the mid-summer dry weather temperatures during the incident, the transfer of oxygen from the atmosphere to the water would have been very slow. This would have been serious impact on the invertebrates in the creek. Low DO had very likely contributed to the death of crayfish and invertebrates in the main pond of Mill Creek. If tadpoles were present at the main pond, they would have definitely been affected because they require greater oxygen to survive.
60. In summary, the extremely high ammonia at the main pond, and moderately high ammonia in at least 800-metre length of Mill Creek downstream of the discharge point of the spill, for 2 to 7 days following the incident, were sufficient to cause serious adverse effects on invertebrates, and tadpoles if present. The dead crayfish and other invertebrates was evidence of the impact of ammonia. Further, it would have effects on the ecosystem structure and functioning. Effects would have continued but decreased in the next 4 weeks when ammonia concentrations were decreasing. Ammonia levels exceeded the ANZECC (2000) WQG.
61. High conductivity for 2 days following the incident, would have contributed to the death of crayfish and also adversely affected invertebrates.
62. The presence of leachate material in about 800-metre length of Mill Creek immediately following the incident, most likely reduced the DO significantly. Laboratory tests indicated that the DO levels were most likely lower than the WSN licence limit. Low DO would have contributed to the adverse effects on invertebrates and tadpoles if present.
63. The overflow caused a change in the chemical composition of the Creek waters. The visual observations made by DEC staff who inspected Mill Creek at various times after the incident and the results of chemical analysis of both NSW EPA Chemistry laboratories and WSN, gave clear evidence to this. The presence of leachate in 800-metre length of Mill Creek had most likely also reduced the DO significantly.
64. The results of toxicity tests by the EPA Ecotoxicology Section and comparison with ANZECC WQGs gave evidence that the spilt leachate material had serious adverse effects on organisms in approximately 800-metre length of Mill Creek for 2-7 days following the incident. The factors that contributed to this were high ammonia and conductivity, and the likely reduced DO in leachate-contaminated waters. The ANZECC WQG for ammonia and recommended guideline for conductivity, were exceeded for 5 weeks and 2-7 days respectively. Extremely high ammonia concentrations were sufficient to cause the death of crayfish and other invertebrates observed by witnesses at the main pond of Mill Creek. Adverse effects on organisms at the main pond would have continued for 5 weeks following the incident."
134 Mr Anink inspected Mill Creek on 14 January 2005, some 4 days after the pollution incident. He inspected the creek pools downstream of the spill entry. He made the following observations:
"11…I observed that impacted pools had a dark brown-black colour sometimes with a sheen on the surface and with a distinct odour including that of ammonia…I noted the lack of swimming (submerged) macroinvertebrate fauna (although there were a few water striders observed in some pools) and the presence of dead or dying freshwater crayfish (mostly juvenile Euastacus sp ., and most probably the Sydney crayfish, E. spinifer ). These observations were made of pools downstream to a long natural rock bar in the creek line."
135 He concluded:
"14. Based on the observations of contrasting water appearance, contrasting water odours, presence or absence of aquatic macroinvertebrate fauna including the observations of dead or dying crayfish, I concluded that, as at 14 January:
(i) The initial spill had been contained in creek ponds within Mill Creek for a distance of about 800 m downstream of the discharge point, above a natural rock-bar section. I estimated this distance by reference to the first downstream tributary draining into Mill Creek from the east (some 40 to 50 m further downstream).
(ii) The section of Mill Creek upstream of the discharge point was not impacted by the spill.
(iii) The section of Mill Creek, from the rock-bar referred to in 14(i) above through to MC3, was not impacted by the leachate spill, at least to the extent that there was no obvious dark or discoloured water colour, no ammonia odour, no dead or dying aquatic fauna observed plus live aquatic macroinvertebrates (including live juvenile crayfish) observed in and on the water.
(iv) Based on similar observations outlined in 14(iii) above I concluded that the section of Mill Creek observed below the coffer dam at MC3 was not impacted by the leachate spill".
136 Mr Anink made recommendations for clean-up operations. Mr Anink designed and supervised an aquatic macroinvertebrate monitoring program. The monitoring was undertaken on 18 and 19 January 2005 (8-9 days after the pollution event). A repeat aquatic sampling program was undertaken on 12 May 2005. Mr Anink compared the results obtained from these surveys. Mr Anink summarised the comparison as follows:
"26…The results confirm that sites Refill Pond and Impact Pond were impacted by the spill of leachate on 18 January 2005 and that Impact Pond had recovered sufficiently to support a diverse range of aquatic macroinvertebrate to a level comparable with Reference sites by May 2005. The fauna included several taxa with SIGNAL scores of 5 and 6 (i.e., mildly pollution intolerant taxa) which were not found during the January 2005 sampling.
27. Crayfish had not re-colonised the impact section of the creek by May 2005 but, given the intact population upstream, colonisation from upstream (at least) could be expected during the next summer. Tadpoles were observed U/S Ref and D/S Ref at the 'During' surveys and at U/S Ref plus Impact Pond at the May survey. The Plague minnow (a listed pest species) was observed at D/S Ref at both surveys and at LH15 in May 05."
137 Mr Anink assessed the impact of the pollution to be as follows:
"28. Based on the combined chemical and biological data contained in the affidavits and from my own observations and measurements I conclude that the spill of leachate to Mill Creek on 10 January 2005 caused a spike of toxic but non persistent chemicals to be deposited in the waters of the creek, which caused a pulse impact on the aquatic biota of the creek. The pulse had the form of a sharp peak with a long tail recovery. There was most likely a sharp and immediate rise in toxicity during the leachate spill with high levels of toxicity remaining for about a week, followed by a gradual decrease in toxicity over the next four weeks.
29. Based on the combined chemical analysis results produced by WSN, NSW EPA, this report and CES (2006), it is apparent, as concluded by Dr Pablo in her affidavit at paragraph 35, that ammonia was "clearly the principal chemical-of-concern affecting aquatic life" exacerbated by high BOD and resulting low Dissolved Oxygen concentrations.
30. I also agree with Dr Pablo that the creek length directly impacted by the leachate spill was around 800 m downstream from the discharge point and was contained by a rock bar at that point.
31. My aquatic biota monitoring also confirms Dr Pablo's opinion that the chemical impacts in terms of ammonia, BOD and dissolved oxygen were probably most severe at the discharge pond (at MC1) with a gradual decrease downstream for 800 m. Adverse effects on aquatic biota within this creek length would have continued for up to five weeks following the incident.
32. I also note that aquatic ecological impacts were confined to the area of the creek above MC3 and most likely confined to the jointly agreed immediate creek impact length of 800 m, by the combined imposition of a coffer dam at site MC3 and by the prompt commencement of the clean-up procedure.
…
35. The aquatic ecological monitoring undertaken in May 2005 confirmed that recovery in the main section of the impacted creek section had proceeded to a sufficient degree such that the ponds supported a diverse range of macroinvertebrate taxa, with a community structure similar to that found at reference sites within Mill Creek and at a site in a reference creek.
36. It is concluded that as the main constituents of the leachate spill were degradable there is unlikely to have been any further intermediate impacts and no long-term impacts of the leachate spill on the aquatic ecology of Mill Creek, Lucas Heights."
Sentencing considerations
138 The sentence imposed by the Court must reflect (be proportionate to) both the objective gravity or seriousness of the offence and the personal or subjective circumstances of the defendant: Veen v R (No 1) (1979) 143 CLR 458 at 490; Veen v R (No 2) (1998) 164 CLR 465 at 472; R v Scott [2005] NSWCCA 152 (18 April 2005) at [15].
Objective gravity of the offence
139 The primary factor to consider is the objective gravity or seriousness of the offence: Lawrenson Diecasting Pty Limited v WorkCover Authority of New South Wales (Inspector Ch'ng) (1999) 90 IR 464 at 474, 475 and Fletcher Construction Australia Limited v WorkCover Authority of New South Wales (Inspector Fisher) (1999) 91 IR 66 at 77-80.
140 The objective gravity or seriousness of the crime fixes both the upper and lower limits of proportionate punishment. It fixes the upper limit because a sentence should never exceed that which can be justified as appropriate or proportionate to the gravity of the crime considered in light of its objective circumstances: Veen v R (No 2) (1988) 164 CLR 465 at 472, 485-486, 490-491 and 496; Baumer v R (1988) 166 CLR 51 at 57-58; Hoare v R (1989) 167 CLR 348 at 354. It fixes the lower limit because allowance for the subjective factors of the case, particularly of the offender, cannot produce a sentence which fails to reflect the objective gravity or seriousness of the offence (R v Dodd (1991) 57 A Crim R 349 at 354; R v Nicols (1991) 57 A Crim R 391 at 395; R v Allpass (1993) 72 A Crim R 561 at 563; R v Murray (unreported, NSW Court of Criminal Appeal, 22 October 1997) at pp 6-7 per Barr J with whom Newman J agreed; and R v Scott [2005] NSWCCA 152 (18 April 2005) at [15]), or the objectives of punishment such as retribution and general and individual deterrence (R v McGourty [2002] NSWCCA 335 (13 August 2002) at [34] and [35]).
141 In determining the objective gravity or seriousness of the offence the Court may have regard to a number of factors, many of which are required to be considered by the Act. I will deal with those relevant to the circumstances of this offence and the defendant.