The Surface Waters (Dangerous Substances) (Classification) Regulations 1997 No. 2560

Regulation 2

SCHEDULE 1 CRITERIA FOR CLASSIFICATION DS4

1.  Subject to paragraph 2 below, the requirements for the classification DS4 are that—

(a) 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 above does not exceed the relevant limit shown in column (2); and

(b) the concentration of each substance listed in column (1) of Table 2 in each sample so taken does not exceed the relevant limit shown in column (2).

2.  Where samples are taken in accordance with regulation 4 above from more than one sampling point in relation to the waters in question, the requirement in paragraph 1(a) above must be satisfied in relation to the samples from each sampling point.

Table 1

(1)	(2)
Dangerous substance	Limit (in microgrammes per litre) (annual mean)
Arsenic	50
Atrazine and Simazine	2 (for the two substances in total)
Azinphos-methyl	0.01
Dichlorvos	0.001
Endosulphan	0.003
Fenitrothion	0.01
Malathion	0.01
Trifluralin	0.1

Table 2

(1)	(2)
Dangerous substance	Limit (in microgrammes per litre)
Tributyltin	0.02
Triphenyltin and its derivatives	0.02