Quality standards stipulated in the Shellfish Waters Directive

Parameter

Unit

G

I

A. GENERAL PHYSIO-CHEMICAL PARAMETERS
Colour

 

 

(a)

Dissolved oxygen

% sat

>80 T95

>70 TAA(b)

pH

 

 

7-9 T75

Salinity

g/kg

12-38 T95

40 T95(c)

Suspended solids

 

 

(d)

Tainting substances

 

 

(e)

Temperature

 

(f)

 

B. METALS AND INORGANIC ANIONS
Arsenic

 

(g)

(h)

Cadmium

 

(g)

(h)

Chromium

 

(g)

(h)

Copper

 

(g)

(h)

Lead

 

(g)

(h)

Mercury

 

(g)

(h)

Nickel

 

(g)

(h)

Silver

 

(g)

(h)

Zinc

 

(g)

(h)

C. ORGANIC SUBSTANCES
Hydrocarbons

 

 

(i)

Organohalogens

 

(g)

(h)

D. MICROBIOLOGICAL PARAMETER
Faecal coliforms

per 100 ml

300 T75(j)

 

Notes:

G guide value

I imperative (mandatory) value

T total concentration (ie without filtration)

D dissolved concentration ie usually involving filtration through a 0.45-Ám membrane filter before analysis

AA standard defined as annual average

75 standard defined as 75-percentile

95 standard defined as 95-percentile

MA maximum allowable concentration

Pt/l concentration of platinum (Pt) determined photometrically on the Platinum/Cobalt scale as a measure of colour in water

A discharge affecting shellfish waters must not cause an increase in colouration of more than 10 mg Pt/l compared to the waters not so affected (waters filtered in both cases). This standard is expressed as a 75-percentile.

If an individual result indicates a value lower than 70% of saturation, the measurement must be repeated. Concentrations below 60% of saturation are not allowed, unless there are no harmful consequences for the development of shellfish colonies.

A discharge affecting shellfish waters must not cause an increase in salinity of more than 10% compared to the water not so affected. This standard is expressed as a 75-percentile.

A discharge affecting shellfish waters must not cause an increase in the concentration of suspended solids by more than 30% compared to the water not so affected. This standard is expressed as a 75-percentile.

The concentration of substances affecting the taste of shellfish must be lower than that liable to impair the taste of the shellfish.

A discharge affecting shellfish waters must not cause an increase in temperature of more than 2 C compared to the water not so affected. This standard is expressed as a 75-percentile.

The concentration of this substance or group of substances in shellfish flesh must be so limited that it contributes to the high quality of shellfish products.

The concentration of this substance or group of substances in water or in shellfish flesh must not exceed a level which gives rise to harmful effects in the shellfish or their larvae. Synergistic effects must also be taken into account in the case of metal ions.

Hydrocarbons must not be present in water in such quantities as to produce a visible film on the surface of the water and/or a deposit on the shellfish, or to have harmful effects on the shellfish.

In shellfish flesh and intervalvular fluid. However, pending the adoption of a directive on the protection of consumers of shellfish products, it is essential that this value be observed in waters from which shellfish are taken for direct human consumption.

References