Table 1 . Samples collected from different provinces from south to the north of Iran .

Province from north to south	Number of sample	Δ32/wt frequency	Δ32/Δ32 frequency
Gilan	20	1	0
Azarbaijan-e- sharghy	50	1	0
Azarbaijan-e-gharbi	50	1	0
Ghazvin	45	1	0
Tehran	100	2	1
Semnan	30	0	0
Kurdistan	35	0	0
Ghom	30	0	0
Isfahan	40	0	0
Khorasan	40	0	0
Yazd	30	0	0
Lorestan	30	0	0
Hormozgan	30	0	0
Total	530	6	1