7728ddac-7920-488b-bb08-62bbebe6d0ea

MSFD: Key Contaminants in Shellfish

This dataset was created as part of the MSFD article 8, 9 10 reporting.

Key for contaminants in shellfish

Background:
As shellfish can accumulate many contaminants, concentrations of contaminants in shellfish provide a good indicator of water quality with respect to the contaminants. These data represent the assessment outputs for contaminants in bivalve molluscs (Mytilus edulis, Ostrea edulis and Crassostrea gigas from the OSPAR Coordinated Environmental Monitoring Programme (CEMP) Assessment 2012 (data to 2010?). This involves statistical assessment of contaminant status and, where sufficient data are available, temporal trends. A weighted regression model is fitted to the annual contaminant indices. The type of model depends on the number of years of data:
• 1-2 years: no model
• 3-4 years: mean
• 5-6 years: linear trend
• 7+ years: smoother
The fitted models are used to assess environmental status against available assessment criteria and evidence of temporal change in contaminant levels in the last ten years.

Indicative parameters included in Atlas:

Metals
? Cd – Cadmium
? Hg – Mercury
? Pb – Lead

Polyaromatic hydrocarbons (PAH)

? BaP - Benzo(a)pyrene
? Flu – Fluoranthene

Organochlorine substances

? CB153 – polychlorinated biphenylcongener 153
? DDEpp – p,p’-DDE: breakdown product of pesticide DDT (Dichloro-diphenyl-trichloroethane)


Status Assessment Key– Colour:

Final year upper one-sided 95% confidence intervals are assessed against relevant assessment criteria, specifically

(Blue Circle)
Below Background Assessment Concentrations (BACs): contaminant concentrations are “close to zero” for synthetic substances or “near background” for non synthetic substances

(Green Circle)
Above BACs but below OSPAR Environmental Assessment Criteria (EACs).EACs represent a concentration below which it can be assumed there is little or no risk to the marine environment and its living resources . N.B. EACs are not available for mercury, cadmium and lead. In these cases EC food standards for bivalve molluscs are used (Regulation 1881/2006/EC as amended)

(Red Circle)
Above OSPAR EAC and therefore it cannot be assumed that there is little or no risk to the marine environment and its living resources. Potential for negative effects.

(Orange Circle)
As there are no EACs or equivalent used in the OSPAR assessment for DDEpp, values above background are designated as orange, indicating that while concentrations are not designated as “close to zero” , no assessment of environmental risk can be made.

(Black Circle)
No Status Assessment


Trend Assessment Key - Shapes

Temporal trend assessment are carried out where more than 5 years data are available. Linear trends are assessed for 5-6 years data. Loess smoothers are used to assess trends for >6 years.

(Black Upward triangle)
Statistically significant upward trend detected

(Black Downward triangle)
Statistically significant downward trend detected

(Large Black Circle)
No statistically significant trend detected

(Small Black Circle)
Status assessment only (no trend assessment)

(Hollow Large Circle)
Informal status assessment


Note of Caution - Over-interpreting status and trend assessments at local level should be avoided. For instance red attributions could reflect wide uncertainty bands for the individual dataset and there is a statistical probability (albeit low) of detecting a significant trend where none exists. Moreover, the contaminants assessed are globally ubiquitous contaminants due to long range transport pathways and are considered environmentally persistent. For more information on hazardous substances in the marine environment see Chapter 5 the OSPAR Quality Status Report 2010 http://qsr2010.ospar.org/en/ch05.html

More parameters, statistical assessment outputs and information on methodologies is available at http://dome.ices.dk/osparmime/main.html

Marine Institute

2015-06-23 12:58:25

Marine Institute

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