What are some of the adverse effects of industrial emission

Question

Hydrogeology

Question 1a. Explain the ¹⁴C method of dating groundwater. Include in your answer an explanation of the age range that ¹⁴C is useful for, the form and origins of C in groundwater systems, the complications and uncertainties inherent in using this technique for dating groundwater, and an example of a study that has used ¹⁴C to date groundwater.

Question 1b. You have been asked to carry out a study of recharge in a semi-arid low relief area with little runoff.

Existing data include:

a) a set of shallow bores with screens close to the water table and hydrograph records for the last 20 years;

b) some deeper bores with screens several metres to tens of metres below the water table that also have hydrograph records; and

c) basic major ion geochemistry. You also have the opportunity to measure concentrations of ³⁶Cl, ¹⁴C, and ³H in the groundwater.

Briefly outline how you would use these data to estimate recharge in this area, including the timescales and distance scales over which the various techniques give you information.

Question 1c. Explain how ²²²Rn allows us to estimate groundwater inflows to a river. Include in your answer an explanation of why Rn is a suitable tracer, the factors that control the ²²²Rn activities in a river, the parameters that we need to estimate or measure to calculate the groundwater inflows, and any problems or uncertainties with this technique.

Question 1d. Hydrocarbons are common groundwater contaminants. Explain: some of the sources of hydrocarbon contamination, in what state do we find the contaminants, the factors that control the rate of contaminant migration, and how the contaminants might degrade naturally in the environment.

Question 1e. The hydrogeology of the Freshwater Lenses along the River Murray was used as an example of a groundwater recharge from a losing stream. Explain how a) the bore hydrograph data; b) the radiogenic isotope data; and c) the stable isotope data were used to determine that recharge occurred largely through the river bank and not via the floodplain

Question 1f. Figures 1a and 1b show stable isotope, ¹⁴C, and ³H data for groundwater from three aquifers from an area of ~10km x 20km. The area has subdued topography and there is little variation in annual rainfall across the area. Modern rainfall has a 3H activity of 4.2 TU and the soil zone CO₂ has an a¹⁴C of 105 pMC. The global meteoric water and the stable isotope values of average modern rainfall are also shown. Use these data to explain the relative ages of the groundwater in the different aquifers and hydrological processes that have affected the groundwater. Integrate as much of the data as possible.

Environmental Geoscience

Question 2a. The Big BadgerCarbonate-hosted Lead-ZincMine was closed 20 years ago. Your department at the State Government has been monitoring the geochemistry of these tailings ever since the mine closed.

The mine does not have an acid drainage problem because it is carbonate hosted; however, mine waters have elevated concentrations of toxic metals: Pb, Zn and cadmium (Cd). Since mine closure, extensive hardpans rich in gypsum, CaSO₄·2H₂O, have formed at the surface of the tailings.

Your department is under pressure to form commercial partnerships to help fund rehabilitation of old mine sties. An entrepreneur has approached your department with a proposal to mine the tailings for gypsum (gypsum is used as a fertiliser, an additive in food processing and the primary ingredient in plasterboard). You have been asked by the director of your departmentto approve or reject this proposal. You must make your decision on the basis of whether or not the gypsum is safe to use for these purposes.

Use the recent quantitative XRD data available to you in Figure 1 and the information in Table 1 to make your decision and to justify your answer.

Figure 2: Quantitative X-ray diffraction data for selected minerals at Big Badger Mine

Table 1: Comparison of ionic radii for elements in Big Badger tailings minerals

Ion	Atomic radius, rion [Å]	100%×|rion - rCa|/rCa
Ca2+(VI)	1.14	----
Pb2+(VI)	1.33	16.7%
Cd2+(VI)	1.09	4.4%
Zn2+(VI)	0.88	22.8%
Fe2+(VI)	0.92	19.3%

Question 2b. (i) What are some of the adverse effects of industrial emission of SO₂ into the atmosphere?

(ii) Use either (1) SO₂ pollution from the Inco Superstackor (2) SO₂ pollution in Antwerp, Belgium to describe how SO₂ concentration and stable sulfur isotopes in the atmosphere, plants and minerals can be used to trace the source of SO₂.

Be sure to use diagrams to explain the graphing techniques that can be used to trace SO₂ pollution. Make reference to the spatial scale over which these techniques may be used to trace pollution.

Question 2c. Explain how oxygen and carbon stable isotope data, as well as radiocarbon data, can be used to trace the source of CO₂ and H₂O in carbonate minerals. Also explain how ¹⁴C data can be used to estimate the date of formation for carbonate minerals produced during the 20th and 21st centuries (using the "Bomb Spike"). Use diagrams as appropriate.

Question 2d. Give a specific example of how mineral-microbe interactions can be employed for contaminant mitigation and environmental remediation. Be sure to identify:

a) which micro-organism(s) and mineral(s) are involved in the process,

b) the chemical/metabolic reactions used by these organisms (including which elements are used as electron donors and acceptors), and

c) how the mineral-microbe interaction leads to the desired outcome for remediation.

Question 2e. You were given several examples of how the relationships between minerals and microbes can be used to sequester toxic heavy metals. Describe one of the case studies covered in lecture. Specifically, identify a) the contaminant metal, b) the micro-organism employed in remediation, and c) the mineral produced by the micro-organism. Finally, give a brief description of how the micro-organism changes geochemical conditions to sequester the contaminant metal in a mineral.

Question 2f. You have been asked to determine the source of carbon in minerals forming within the mine tailings at the Fantastic Bling Diamond Mine. You have been provided with stable C and O isotope data and ¹⁴C data on DIC, atmospheric CO₂, mine camp sewage (which is disposed of in the tailings), and carbonate minerals from fresh ore and tailings. You also have the opportunity to collect X-ray diffraction data and to do scanning electron microscope imaging on any of these samples. Briefly outline how you would use these data to identify the source of carbon in tailings minerals at Fantastic Bling.

Question 2g. Chemical weathering is a critical step in Earth's biogeochemical element cycles. Describe (i) some common mechanisms of chemical weathering, (ii) how silica polymerisation and metal cation size control the rates at whichdifferent silicate minerals weather, and (iii) the role that bacteria can play in enhancing chemical weathering.

Question 2h. Draw a generalised box model of one of Earth's biogeochemical cycles, including the four spheres of the Earth System. Define the terms (i) reservoir, (ii) flux, (iii) source and (iv) sink and use your box model to provide examples of each.