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 | Colouration (after filtration) | mg Pt/1 | A discharge affecting shellfish waters must not cause the colour of the waters after filtration to deviate by more than 10mg Pt/1 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/1 | A discharge affecting shellfish waters must not cause the suspended solid 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 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. | Conductmetry. | 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 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 one sample representative of low oxygen conditions on the day of the 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:
| Visual examination. | Quarterly | |
| 8 | Organohalogenated 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 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. |