Question

1.            Discuss the likely primary sources of these ions in the Cedar Creek stream water in relation to types of the weathering reactions investigated in the Earth Science practical (100 words).

2.            What are some other possible sources of these ions (100 words)?

	Cations (ppm/mg/L)
Stream Transect	Al	Ca	Fe	K	Mg	Na	S	Si
Transect 1	0.007	8.49	0.17	1.77	17.17	5.28	0.86	9.44
Transect 5	0.007	8.15	0.14	1.71	16.36	5.04	0.85	9.01
Transect 8	0.007	8.12	0.21	1.69	16.09	5.01	0.82	8.84
Transect 10	0.007	8.92	0.21	2.32	17.93	5.47	0.95	9.63
Transect 12	0.007	8.49	0.26	1.86	16.64	5.25	0.86	9.15
		Anions (ppm/mg/L)
	Fl	Cl	NO₂	SO₄	Br	NO₃
Transect 1	0.00	21.51	0.17	2.56	0.12	0.31
Transect 5	0.00	21.34	0.23	2.51	0.12	0.32
Transect 8	0.00	21.84	0.24	2.54	0.12	0.32
Transect 10	0.00	25.01	0.29	2.91	0.13	0.32
Transect 12	0.00	24.66	0.28	2.87	0.13	0.37

Answer 1

1) The likely sources of different Cations and Anions in the Cedar Creek stream water in relation to weathering are physical weathering of rocks and soils (due to variation in temperature or by air, wind, etc.) from where this river passes. Similarly, the chemical weathering of different rocks, soils, sands get mixed into river water (or reacts with acids or gases or rainwater in the atmosphere) and gets separate into ions. Similarly, biological weathering is caused mainly by living organisms such as plants, animals and human beings. The plants may grow on the rock/soil and weathering causes, similarly, animals, human beings and their remainings after their death also cause weathering in rocks, soils, fossils causing exposure to different ions on the river system.

2) Apart from different types of weathering, there are many other ways that cause ions to occur in the river water such as disposal of solid/liquid wastes to the river water. Similarly, the different gases such as CO₂, O₂, N₂O, etc get to react with river water while flowing through different channels forming different cations and anions. Also, rain water, ice, snow, etc. get dissolve or precipitate and mixes with river water to form different ions. In the same way, flooding and land/soil erosion cause the ions to a mix-up with river water. Whereas, the mixing of groundwater, natural contaminations, anthropogenic activities can also help in the mixing of different ions in the Cedar Creek stream water.