# Surface Waters (Dangerous Substances) (Classification) Regulations (Northern Ireland) 1998, Schedule 3: Criteria for Classification DS3


The criteria for the classification DS3 are that the annual mean concentration of each substance listed in column (1) of Table 3 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.
TABLE 3
(1)
(2)
(3)
Substance
Concentration in microgrammes per litre (annual mean)
Reference method of measurement
Note The accuracy and precision of the method must be plus or minus 50% at a concentration which represents twice the value of the limit of determination.
1,2-Dichloroethane
10
Gas chromatography with electron capture detection after extraction by means of an appropriate solvent or gas chromatography following isolation by means of the “purge and trap” process and trapping by using a cryogenically cooled capillary trap. The limit of determination is 1 µg/litre. (see Note)
Trichloroethylene
Perchloroethylene
10
10
Gas chromatography with electron capture detection after extraction by means of an appropriate solvent. The limit of determination is 0.1 µg/litre. (see Note)
Trichlorobenzene
0.4 (but there must be no significant increase over time in the concentration of trichlorobenzene in sediments and/or molluscs and/or shellfish and/or fish)
Gas chromatography with electron capture detection after extraction by means of an appropriate solvent or, when used to determine the concentration in sediments and organisms, after appropriate preparation of the sample. The limit of determination for each isomer separately is 10 ng/1 for the water environment and 1 µg/kg of dry matter for sediments and organisms. (see Note)

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Source: https://www.legislation.gov.uk/nisr/1998/397/schedule/3 (the official version)
Page: https://openlegislation.uk/surface-waters-dangerous-substances-classification-regulations-northern-ireland-1998/schedule-3
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.