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National Rivers Authority*
Water Analysis Report

The chemical analysis of a water sample. This sample was taken from a pond at the Woodland Education Centre. 
For an explanation of some of the terms used in the report, click here.

NRA Exeter Regional Laboratory

Automatic Sample Analysis Report Production

Sampling Point : RPL/02B

Date/Time Report Last Run : 08 March 1992 04:20

Date/Time Taken: 25th February 1992 16:00hrs

Pollution Incidents in Catchment 02b

Address: Pond at Offwell Woodland & Wildlife Trust Reserve. (The Woodland Education Centre)

Laboratory Reference: E54281

Samplers Comments: (Mr AF Sweetapple) - "Slight froth"
 

Det. Code

Description

Result

Units/Measure

61

pH

7.5

pH

76

Temperature

No Result

 

81

Oxygen Dissolved % Saturation

107

%

82

Oxygen Dissolved

No Result

 

85

Bod Atu

1.2

mg/l

111

Ammonia expressed as Nitrogen

0.03

mg/l  N

116

Nitrogen Total Oxidised expressed as Nitrate AND Nitrite

1.4

mg/l  N

117

Nitrate

1.39

mg/l

118

Nitrite

0.01

mg/l

135

Suspended Solids 105c

<2

mg/l

143

Solids Non-Volatile 500c

No Result

 

172

Chloride Ion

19

mg/l

180

Ortho-Phosphate

0.02

mg/l

1181

Weather Present - Temperature

 

Misc.

1183

Weather Present - Precipitation

 

Misc.

3106

Analysis By Mass-Spectrometer

Report Filed - Nothing Significant Found.

Misc.

3267

Type of Flow As Description

 

Misc.

 

INTERPRETATION OF ANALYTICAL RESULTS

Dissolved Oxygen D.O. 

Shows the concentration of oxygen dissolved in the water. Generally the more oxygen present the less polluted the water.

Dissolved Oxygen Percent Saturation D.O.%

Shows the concentration of Oxygen present as a percentage of the saturation level at that particular temperature.

Ammonia NH3

This generally arises as a result of the decomposition of organic nitrogenous waste and is usually found in substantial quantities in crude sewage and farm wastes.

Nitrate NO3

Nitrates can originate from compound fertilizers application to farmland or the oxidation of ammonia by bacteria, the process which occurs at a sewage treatment works.

pH

pH is a measure of the degree of acidity or alkalinity of the water.  A pH value of 7 is neutral with values less than 7 being acidic while values in excess of 7 are alkaline.

Biochemical Oxygen Demand B.O.D.

This shows the amount of oxygen that is used by the bacteria in digesting any organic pollutants present in the sample.  Expected levels of B.O.D. are:

Clean River    1-3 mg/l
Treated Sewage   20 mg/l
Crude Sewage   200-300 mg/l
Farm Yard Runoff   1,500-2,000 mg/l
Silage Liquor   60,000 mg/l

Suspended Solids S.S.

Shows the amount of solids that are present in the sample, measured in mg/l.

  * The National Rivers Authority is now part of The Environment Agency

 

 

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