River Ouzel chemical quality

Physical and chemical measurements on the River Ouzel old A5 Road bridge in Bletchley.
Name Units 25/1/95 20/2/95 22/3/95 24/4/95 19/5/95 21/6/95 17/7/95 17/8/95 19/9/95 16/10/95 8/11/95 6/12/95
pH pH units 8 8.2 8.5 8.2 8.4 8.6 8.3 8.4 8 8.2 8.1 8.1
Turbidity FTU 28 8.3 4.2 5.9 3.3 5.3 4.5 10.3 5.3 6.7 6.2 20.9
Temperature °C 6 7 8.5 9 12 20 19 23 16 15 8 4
Conductivity at 25 °C µsie/cm 771 775 793 930 747 770 780 880 770 892 1000 970
Dissolved Oxygen % saturation AE 106 165 123 122 148 112 150 99 108 81 93
Dissolved Oxygen mg/l AE 12.9 19.3 13 13.1 13.4 10.4 12.8 9.78 10.9 9.62 12.2
Biochemical oxygen demand+ATU.5days T mg/l O 1 <1 AE 6.8 3.1 3.4 2.3 <1.5 2.3 1 4.9 3.9
Ammonia N mg/l N 0.26 0.16 0.06 <.03 <.03 <.03 0.05 0.08 0.03 0.13 0.22 0.2
Total oxidised nitrogen as N mg/l N 12 9.6 9.4 9.3 7.5 7.9 5.2 5.6 11.9 8.8 8.9 12.4
Alkalinity CaCO3 mg/l CaCO3 204 234 216 200 190 200 180 200 170 200 200 200
Chloride mg/l Cl 42 43 47 62 55 59 57 68 54 83 81 60
Phosphate sol.react mg/l P 0.27 0.32 0.67 1.2 1.16 1.5 1.8 1.8 1.1 2.8 3.6 1.2
Sulphate mg/l SO4 100 115 106 100 91 100 90 140 110 108 160 140
Cadmium total µg/l Cd 0.1 <.1 <.1 0.1 <.1 <.1 <.1 <.1 0.1 <.1 <.1 0.1
Selenium µg/l Se <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1
Chromium µg/l Cr 2 2 2 2 <1 <1 <1 1 1 <2 3 2
Copper µg/l Cu 6.1 6.3 4.5 5.3 4.1 4 3.8 3.5 3.9 3.9 4.5 7.3
Lead µg/l Pb 6.5 4.9 2.2 2.8 1.5 1 1.2 1.4 1 1 1.3 6.2
Nickel µg/l Ni 6 <5 <5 5 <5 <5 <5 <5 <5 <5 <5 <5
Zinc µg/l Zn 31 32 17 24 12 10 11 10 7 14 20 55
Flow rate m3/second 7.874 3.598 1.903 1.386 1.032 0.678* 0.663 0.513 0.856 0.662 0.525 1.348

Notes: FTU = formazin turbidity units. Standard suspensions of formazin are used to compare with river water. µsie/cm = microsiemens/cm. Biochemical oxygen demand+ATU.5days T = uptake of oxygen from a sample of river water over 5 days. * flow rate measured at Willen rather than Bletchley (which had been vandalised). [Willen and Bletchley flow rates were similar at other dates]


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