William Scott

An early analysis of data for Acid Sulphate Soil ASS detection uses field based measurements of pH and laboratory based measurements of Cl/SO4 and SPOCAS at Ashfield, Western Australia. Statistically, no test is outstanding and the tests are not necessarily the same. Field pH testing is inexpensive and worth doing but statisti¬cally Field pH and Cl/SO4 are insignificantly related (P = 0.045) Fisherʼs Exact Test. Cl/SO4 testing rarely gives a negative result. When the Field pH gives a negative result, Cl/SO4 is unlikely to confirm it. Field pH and SPOCAS are significantly re¬lated (P = 0.022, Fisherʼs Exact Test); large numbers of positive and negative results lend power to this statement. It is particularly concerning that when the Field pH and Cl/SO4 agree, the SPOCAS only gives a positive result 68% of the time, a figure not statistically different to 50%. The follow-up suggests numerical readjustments of the cutoff for the tests and the protocol for ASS in Western Australia, in the shape of a decision tree.

Looks at the ways catalysis can occur through the action of bacteria. With billions of years of evolution, bacteria have taken every opportunity to direct and optimise the reaction coordinate. One model is a staircase with step sizes, shapes, and direction such that there is piecewise control over the whole reaction. Steps of a single size are appropriate; the effect of a series of reactions of smaller activation energies is explored; an optimal number of steps is found, with an individual step being RT. Specific data on Fe(II) oxidation and inoculation with ochre sludge were mined (from Stevenson, 1991); the data are for a controlled pH of 5.8, oxygen at 0.023atms and without nutrient limitations. It seems that 3 to 5 steps are involved in increasing the oxidation rate 3.3 to 7.6 times. A catalytic kinetic model involving protein as a surrogate for cells is used to fit the data. Two simultaneous differential equations evolve and are fitted to the initial and final concentrations of Fe(II) and protein. The observed trends are incompletely fit by the model but the parametric values give some insight into bacterial catalysis. The fractional mass increase in oxidation

I want to report to you the results of my calculations on the step-drawdown test that Andrew com¬pleted before they pulled the pump out. The pump you saw yesterday failed early this week. I believe it was an electrical fault. There was no problem with the hole. They put a new pump in the hole. The question is whether or not we can sense the presence of bacteria. I have done a number of standard tests on wells, through studentsʼ activities over the past 20 years or so, and some specially for this workshop. In addition, Murdoch has commissioned step-drawdown tests or simplest specific capac¬ity tests including outlet pressure and current to the well equipment on irregular occasions through many years with several different consultants. Andrew Ogden of Western Irrigation has completed a number of them, including a recent test on this particular bore hole, in November of last year, and now a step drawdown test with a new pump.

Scripts are presented for slapstick scenes that can allow greater student anticipation, pleasant repetition and teaching enjoyment. This may seem a 'waste' of time but they allow objective, friendly and critical reflection. It is not for every personality and requires a 'tough hide'. This is to present a few teaching scenarios that receive good responses from students, add flavour and have impact on both students and staff. We found this 'happening' in 1995 and 1996, mostly in the first year course, Introduction to Environmental Sciences.

Surface ripping affected the downward movement of water and solutes within a saline dewatered duplex soil profile near Kellerberrin. Prior to ripping, 63% of the total rainfall ended up as runoff and there was little evidence from tensiometric measurements and soil solution samples of significant downward flows of water below a depth of 0.3m. Following ripping to a depth of 0.2m to break a near surface hard layer: runoff was reduced to around 13%; there was some change in soil matrix potential; some leaching of the surface soil occurred; and several preferred water fluxes were intercepted at a depth of 1.5m. These intercepted fluxes were recorded shortly after (<1hr) high intensity rainfall greater than 20mm, suggesting post ripping flow through macropores. The initial chloride storage in the profile was 162t ha-1, approximately 5t ha-1 chloride was leached during the field study (3%). The main leaching mechanism before ripping was runoff (0.5t ha-1). After ripping, flow through macropores and mesopores accounted for 0.5t ha-1 , runoff 0.09t ha-1 with the rest redistributed through the soil matrix.