1.

pH

pH unit

≥7 and ≤9

— electrometry

Measured in situ at the time of sampling

Quarterly

3.

Coloration (after filtration)

mg Pt/1

A discharge affecting shell- fish waters must not cause the colour of the waters after filtration to deviate by more than 10 mg Pt/1 from the colour of waters not so affected.

— Filter through a 0.45 um membrane

Photometric method, using the platinum/cobalt scale

Quarterly

4.

Suspended solids

mg/1

A discharge affecting shell- fish waters must not cause the suspended solids content of the water 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 5 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

Conductivity

Monthly

6.

Dissolved oxygen

saturation %

≥70% (average value) Should an individual measurement indicate a value lower than 70%, measurements shall be repeated

An individual measurement may not indicate a value of less than 60% unless there are no harmful consequences for the development of shellfish colonies

— Winkler’s method

— Electrochemical method

Monthly, with a minimum of 1 sample represent- ative of low oxygen conditions on the day of sampling. However, where major daily variations are suspected, a minimum of 2 samples in 1 day shall be taken

7.

Petroleum hydrocarbons

Hydrocarbons must not be present in the shellfish water in such quantities as to:

• produce a visible film on the surface of the water and/ or a deposit on the shellfish

• have harmful effects on shellfish

Visual examination

Quarterly

8.

Organohalo- genated 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 Ag

• Arsenic As

• Cadmium Cd

• Chromium Cr

• Copper Cu

• Mercury Hg

• Nickel Ni

• Lead Pb

• Zinc Zn

mg/1

The concentration of each substance in the shellfish waters or in the shellfish flesh must not exceed a level which gives rise to 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 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