Fluoride Variations in Rivers on the Slopes of Mount Meru in Tanzania

Table 6

The pH dependence of fluoride leaching from igneous rocks at 25°C.

Tengeru (Solomu)		Nduruma		Maksoro (M1)		Jamera (M2)
pH		pH		pH		pH
3.72	0.26	3.82	0.28	3.85	0.43	3.75	1.28
4.20	0.29	4.17	0.31	4.32	0.49	4.00	1.44
5.34	0.33	5.44	0.72	5.63	0.46	4.05	1.77
6.95	1.37	6.37	0.97	6.76	0.64	4.33	2.15
7.22	2.83	7.47	1.74	7.49	0.68	4.6	2.15
8.51	3.86	8.82	2.73	8.03	1.21	5.69	2.17
9.72	3.95	9.49	2.53	9.17	3.71	6.24	2.28
10.21	3.95	10.73	2.53	10.6	5.95	7.07	2.79
11.94	3.94	10.99	2.53	11.3	6.20	8.25	9.05
12.64	3.94	12.01	2.53	12.34	26.60	9.48	10.3
13.08	3.94	13.37	2.53	13.17	26.85	10.85	18.75
13.55	3.94	-	-	13. 35	26.89	11.07	29.55
-	-	-	-	-	-	12.61	72.5
-	-	-	-	-	-	12.79	73.95
-	-	-	-	-	-	13.17	74.3

in mg/l.