The Surface Waters (Shellfish) (Classification) Regulations 1997

Regulations 2, 3 and 4

SCHEDULE CRITERIA FOR CLASSIFICATION OF WATERS AS SHELLFISH WATERS

No. in Annex to 79/923/EEC	Parameter	Units	Requirements to be satisfied	Reference methods of analysis	Minimum sampling and measuring frequency
1	pH	pH unit	≥7 and ≤9	Electrometry Measured in situ at the time of sampling	Quarterly
3	Coloration (after filtration)	mg Pt/l	A discharge affecting shellfish waters must not cause the colour of the waters after filtration to deviate by more than 10 mg Pt/l from the colour of waters not so affected	Filter through a 0.45 μm membrane Photometric method, using the platinum/cobalt scale	Quarterly
4	Suspended solids	mg/l	A discharge affecting shellfish waters must not cause the suspended solid content of the waters to exceed by more than 30% the content of waters not so affected	Filtration through a 0.45 μm membrane, drying at 105°C and weighing Centrifuging (for at least five minutes, with mean acceleration 2,800 to 3,200g), drying at 105°C and weighing	Quarterly
5	Salinity	‰	≤40‰ A discharge affecting shellfish waters must not cause their salinity to exceed by more than 10% the salinity of waters not so affected	Conductimetry	Monthly
6	Dissolved oxygen	Saturation %	≥70% (average value) If an individual measurement indicates a value lower than 70%, measurements shall be repeated An individual measurement may not indicate a value lower than 60% unless there are no harmful consequences for the development of shellfish colonies	Winkler’s method Electrochemical method	Monthly, with a minimum of one sample representative of low oxygen conditions on the day of sampling. However, where major daily variations are suspected, a minimum of two samples in one day shall be taken.
7	Petroleum hydrocarbons		Hydrocarbons must not be present in the shellfish waters in such quantities as to: produce a visible film on the surface of the waters and/or a deposit on the shellfish, have harmful effects on the shellfish	Visual examination	Quarterly
8	Organo-halogenated substances		The concentration of each substance in the shellfish waters or in shellfish flesh must not reach or exceed a level which has harmful effects on the shellfish and their larvae	Gas chromatography after extraction with suitable solvents and purification	Half-yearly
9	Metals Silver Arsenic Cadmium Chromium Copper Mercury Nickel Lead Zinc	mg/l Ag As Cd Cr Cu Hg Ni Pb Zn	The concentration of each substance in the shellfish waters or in the shellfish flesh must not reach or exceed a level which has harmful effects on the shellfish and their larvae The synergic effects of these metals must be taken into consideration	Spectrometry of atomic absorption preceded, where appropriate, by concentration and/or extraction	Half-yearly
11	Substances affecting the taste of the shellfish		Concentration should be lower than that which is liable to impair the taste of the shellfish	Examination of the shellfish by tasting where the presence of one of these substances is presumed