SCHEDULE 1Criteria for Classification DS1
The criteria for the classification DS1 are that the annual mean concentration of each substance listed in column (1) of Table 1 in samples taken from the sampling point for the waters in question in accordance with regulation 4 does not exceed the relevant limit specified in column (2) of that Table.
(1) | (2) | (3) |
---|---|---|
Substance | Concentration in microgrammes per litre (annual mean) | Reference method of measurement |
Aldrin Dieldrin Endrin Isodrin | 0.01 0.01 0.005 0.005 | Gas chromatography with electron capture detection after extraction by means of an appropriate solvent with a limit of determination of 2.5 ng/1(1). |
Cadmium and its compounds | 5 (total cadmium: both soluble and insoluble forms) | Atomic absorption spectrophotometry after preservation and suitable treatment of the sample. The limit of determination is .25 µg/litre(2). |
Carbon tetrachloride | 12 | Gas chromatography. The limit of determination is 0.1 µg/litre(1). |
Chloroform | 12 | Gas chromatography. The limit of determination is 0.1 µg/1itre(1). |
DDT (all isomers) | 0.025 | Gas chromatography with electron capture detection after extraction by means of a suitable solvent. The limit of determination for total DDT is approximately 4 ng/l, depending on the number of extraneous substances present in the sample(1). |
para-para-DDT | 0.01 | Gas chromatography with electron capture detection after extraction by means of a suitable solvent. The limit of determination for total DDT is approximately 4 ng/l, depending on the number of extraneous substances present in the sample(1). |
Hexachlorobenzene | 0.03 | Gas chromatography with electron capture after extraction by means of an appropriate solvent. The limit of determination shall be within the range 1 to 10 ng/1 depending on the number of extraneous substances present in the sample(1). |
Hexachlorobutadiene | 0.1 | Gas chromatography with electron capture detection after extraction by means of an appropriate solvent. The limit of determination shall be within the range 1 to 10 ng/1, depending on the number of extraneous substances present in the sample(1). |
Hexachlorocyclohexane (all isomers) | 0.1 | Gas chromatography with electron capture detection after extraction by means of an appropriate solvent. The limit of determination shall be within the range 1 to 10 ng/1 depending on the number of extraneous substances present in the sample(1). |
Mercury and its compounds | 1 (total mercury: both soluble and insoluble forms) | Flameless atomic absorption spectrophotometry after suitable pre-treatment of the sample which takes account in particular of pre-oxidation of the mercury and of successive reduction of the mercury ions Hg(II). The limit of detection must be 0.1 µg/litre(2). |
Pentachlorophenol and its compounds | 2 | High pressure liquid chromatography or gas chromatography with electron capture detection after extraction by means of a suitable solvent. The limit of determination is 0.1 µg/litre(1). |
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