... at the beginning of the cultivation period in all provinces, but fell to within the recommended range in Ha Tinh and Nghe An towards the end of the period, An increase in alkalinity in Ha Tinh ... sources in TT-Hue, and for inlets and ponds in Ha Tinh and Nghe An (Figure 10) Sulphide levels were higher than recommended in the outlets in Nghe An, and in Ha Tinh at the beginning of the season Toxic ... 7.94 8. 10 7.11 7.49 8. 36 8. 00 8. 18 8.50 8. 00 8. 19 8. 50 7.94 8. 15 8. 45 7.23 7 .83 8. 65 7.90 8. 23 8. 60 7.75 8. 37 8. 06 7.77 7.93 8. 43 7.99 8. 23 8. 45 7.39 7.79 5.61 5.16 5.41 5.21 4. 38 4.74 5.07 4.71...