# The Surface Waters (Classification) (Scotland) Regulations 1990, Schedule: Criteria for the classification of waters


The limits set out below are maxima
(1)
(2)
(3)
(4)
(5)
No. in Annex II to 75/440/EEC
Parameters
DW1
DW2
DW3
Note
(1) The value is an upper limit set in relation to the mean annual temperature (high and low).
2
Coloration (after simple filtration)
mg/1 Pt Scale
20
100
200
4
Temperature
°C
25
25
25
7
Nitrates
mg/1 NO3
50
50
50
8(1)
Fluorides
mg/1 F
1.5
10
Dissolved iron
mg/1 Fe
0.3
2
12
Copper
mg/1 Cu
0.05
13
Zinc
mg/1 Zn
3
5
5
19
Arsenic
mg/1 As
0.05
0.05
0.1
20
Cadmium
mg/1 Cd
0.005
0.005
0.005
21
Total chromium
mg/1 Cr
0.05
0.05
0.05
22
Lead
mg/1 Pb
0.05
0.05
0.05
23
Selenium
mg/1 Se
0.01
0.01
0.01
24
Mercury
mg/1 Hg
0.001
0.001
0.001
25
Barium
mg/1 Ba
0.1
1
1
26
Cyanide
mg/1 Cn
0.05
0.05
0.05
27
Sulphates
mg/1 SO4
250
250
250
31
Phenols (phenol index) paranitraniline 4 aminoantipyrine
mg/1 C6H5OH
0.001
0.005
0.1
32
Dissolved or emulsified hydrocarbons (after extraction by petroleum ether)
mg/1
0.05
0.2
1
33
Polycyclic aromatic hydrocarbons
mg/1
0.0002
0.0002
0.001
34
Total pesticides (parathion, BHC, dieldrin)
mg/1
0.001
0.0025
0.005
39
Ammonia
mg/1 NH4
1.5
4

---
Source: https://www.legislation.gov.uk/uksi/1990/121/schedule (the official version)
Page: https://openlegislation.uk/surface-waters-classification-scotland-regulations-1990/schedule
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.