2. A large-scale soil column test with a depth of 80×80cm 180cm was carried out in the field. Plant crops on the soil surface. The analysis results of irrigation water and seepage at the depth of 175cm are as follows:
Hydrogeochemical basis
The average value of water seepage in the first 20 days after the start of the test is listed in the table, and R-N is organic nitrogen. After water permeates the soil column, what kind of hydrogeochemical action changes the component concentration?
3. A phreatic aquifer, the upper part of which is coarse sand with a thickness of 10m, and the lower part is medium-fine sand with clay lenses, with a water level of 4.5m Exploration and sampling analysis show that the upper water flows to the lower part, and the DO in the upper water is 2-6 mg/30-50 mg/L, which proves that the water comes from fertilizers. Do in the lower water is 0 mg/L, which is a trace. Diving is mainly supplied by atmospheric precipitation. Try to explain why water drops sharply when it flows from the upper aquifer to the lower aquifer.
4. Assuming that sewage containing NH4-N50mg/L, Ca2+=60mg/L and Mg2+= 12mg/L is used for irrigation, the groundwater depth in the irrigation area is 2m, the CEC of unsaturated soil is 7.2meq/ 100g, and the paddy field is continuously irrigated 100 days. Assuming that all sewage is adsorbed by the vadose zone soil layer, what is the adsorption capacity of the vadose zone soil layer under 100m2 irrigation area? Is the groundwater polluted? (Hint: refer to Example L in this chapter; Answer: The adsorption capacity of soil layer in vadose zone is 89.64kg. )
5. Why is Cr easier to pollute groundwater than Hg, Pb and Cd?
6. The pH value of acid pit drainage in a lead-zinc mine is 3, and Pb2+ is 4 mg/L. When the acid pit drainage flows through limestone, the following reactions will occur:
Hydrogeochemical basis
As a result, the pH value increased to 7.8, and Pb2+ decreased to 0.3 mg/L. Eh changed little during the flow. Describe the reasons for the increase of pH value and the decrease of Pb2+, and list the corresponding chemical reaction formulas.
7. The adsorption equilibrium test of F- was carried out in the laboratory, and the following data were obtained: the equilibrium concentration of C and F- in the solution; Fluorine is adsorbed in soil.
Hydrogeochemical basis
Please use graphical method (or regression method) to get Langmuir isothermal adsorption equation and Sm. (Answer: Langm-uir isothermal adsorption equation, C/S = 0.0 184+0.00439c, R = 0.9980, SM = 227.8mg/kg).
8. In a certain place in Germany, diving was polluted by arsenic-containing flue flushing. 197 1 year, the average As in groundwater is 22.7 mg/L, and Fe2+ is 0.2-140 mg/l; During the period of1976.10-1977.5, water with KMnO4 concentration of 2000mg/L was injected into the aquifer through 17 water injection hole, and KMnSO429kg was injected. Results The concentration of arsenic in groundwater dropped rapidly to 0.06 mg/L. Q: (1) The existing forms of arsenic in groundwater before treatment (197 1 year); (2) The existing forms of arsenic in groundwater and the reasons for the rapid decline of arsenic concentration in groundwater after KMnO4 injection.
9. It is known that F0C in sediments is 0.0 1, and lgK0wc values of trichloroethylene, tetrachloroethylene, lindane and DDT are 2.29, 2.60, 3.72 and 6. 19 respectively. Calculate the K0c and Kd values of these four organic compounds, and explain which organic compounds are the easiest to migrate in sediments and which are the most difficult to migrate. [Hint: Use formulas 5.23 and 5.15; Answer: The values of K0c and Kd of trichloroethylene, tetrachloroethylene, lindane and DDT are (L/kg):4 19.5, 6 18.5, 25 15.8, 55508. 1 and 4.20, 6 respectively.
10. Why don't microorganisms (bacteria and viruses) form a large area of groundwater pollution? Why does microbial pollution of groundwater often appear after rain?
1 1. The following are the background values (or background interval values) of the study area and the measured concentrations of water samples A, B and C. Please evaluate the pollution levels of the three water samples (by comprehensive pollution index method).
12. What are the similarities and differences between groundwater pollution assessment and groundwater environmental quality assessment?
13. What are the similarities and differences between the principles and methods of dividing the first-class protection zone and the second-class protection zone in the underground water source protection zone?
14. What effect does the abundance of elements in geological environment have on human health? And give an example.
Hydrogeochemical basis
The unit is lmg/l.