Creek 2 and Dam 2- Analysis of Samples Taken 16 & 17 August and 26 September 2007- Chemical Testing
223. On 16 August 2007, 17 August 2007, and 26 September 2007 solid and liquid samples were taken from Creek 2 and Dam 2 and were later analysed and compared to samples taken from reference points.
224. The results of chemical testing showed that as a consequence of the negligent disposal of waste by the Corporation:
a. The soil samples taken in the vicinity of Creek 2 had elevated concentrations of arsenic, sulphur, calcium, copper, strontium, tin and zinc.
b. The soil samples taken in the vicinity of Creek 2 had elevated levels of up to 290 mg/kg of molybdenum.
c. The solid samples taken in the vicinity of Creek 2 had elevated levels of sulphur, calcium, strontium and copper.
d. In general, the concentrations of metals in the samples collected in September 2007 were higher than in the corresponding samples collected in August 2007, which may indicate that elements in the overlying aqueous liquids may have been incorporated into the solids as the liquids evaporated
e. There were qualitative and quantitative differences in the concentrations of elements and in the material collected from the creek, suggesting that a variety of materials may have been deposited there.
f. The solid samples taken in the vicinity of Creek 2 contained a range of free fatty acids and fatty acid esters, demonstrating that vegetable oil was present.
g. The solid samples taken in the vicinity of Creek 2 contained a range of organic compounds, including methyl phenol, various hydrocarbons and aldehydes.
h. The solid samples taken in the vicinity of Creek 2 also contained phenols, including tricholorophenol and tetrachlorophenol. Chlorophenols are highly toxic to both terrestrial and aquatic organisms and are commonly used in insecticides, fungicides and bactericides in products such as wood preservatives and disinfectants.
i. The liquid samples taken from Creek 2 had elevated levels of molybdenum.
j. The liquid samples taken from Creek 2 had high levels of BOD (2,300 to 7,000 mg/L), COD (4,000 to 19,000 mg/L) and ammonia (44 to 93 mg/L).
k. The liquid samples taken from Creek 2 contained fatty acids and fatty acid esters.
l. One liquid sample taken from Creek 2 contained DEET.
m. One liquid sample from Creek 2 contained terpin. Terpin is a compound which, like diethyltoluamide, is often found in landfill leachates and was also found in samples of leachate from the Eastern Creek Waste and Recycling Centre.
n. The major waste material in Creek 2 was a sludge material that contained vegetable oil and animal fat. The vegetable oil component contained canola oil as evidenced by the amounts of brassicasterol in the samples. The presence of animal fat was also demonstrated by elevated levels of cholesterol in the samples.
225. All samples taken in Creek 2, apart from the sample from Dam 2, contained high levels of BOD (2300 to 7000 mg/L), COD (4000 to 19000 mg/L) and ammonia (44 to 93 mg/L). These results are consistent with the liquids being derived from waste containing a large amount of organic material such as effluent from food processing, manure waste or landfill leachate.
226. The physical properties and behaviour in the environment of vegetable oil and animal fats are similar to those of petroleum oils. Like petroleum oils, vegetable oils and animal fats can do the following:
a. create slicks on surface water and form emulsions and sludge that can be lethal to wildlife;
b. cause harmful physical effects, such as coating animals and plants with oil and suffocating them by oxygen depletion;
c. be toxic or form toxic products;
d. destroy future and existing food supplies, breeding animals and habitat;
e. produce rancid odours;
f. form products that linger in the environment for many years; and
g. catch fire when ignition sources are present.
227. Spills of vegetable oils and animal fats can have devastating effects on the environment. Ecosystems may take years to recover or may never recover from spills. Because of their insolubility and lower density, oils form a layer on the surface of water such that oxygen exchange between the gas and liquid phases decreases. As a result the water becomes depleted in dissolved oxygen, and aquatic life is potentially smothered. Furthermore, this effect is magnified as a result of the high BOD values when microbial degradation of the oil takes place.
228. Although vegetable oils and animal fats can biodegrade rapidly, in some situations polymerisation can occur and relatively hard intractable material can be produced that forms a persistent, impermeable cap over sediments, reducing the rate of oxygen diffusion into the sediments. One difference between vegetable oils and animal fats and petroleum oils is that most have lower volatility than petroleum oil. As a result, less of the material is removed from a spill by evaporation, however, the combustion and explosive potential of these oils is reduced.
229. The sludge in Creek 2 was rich in vegetable oil and animal fat. This sludge and the free oil that separated from it are likely to have smothered the creek bed and suffocated biota that was not able to move. In addition, the sludge and free oil was likely to have smothered the roots of nearby vegetation, having deleterious effects.
230. In rainfall events, there is potential for oil to be mobilised and to form a film over water bodies in the receiving environment and harm the biota living in these water bodies as well as animals and birds that drink and forage in the water. An additional concern is that toxic chemicals that have been found mixed with the waste will dissolve into the oil and be transported in the oil in an undiluted form to have deleterious ecological effects beyond Creek 2.