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Listen to this siteWednesday 15 June 2005
This research project developed a database of domoic acid levels in king scallops in Scottish offshore waters, and investigated the time taken for potentially hazardous levels to fall below the regulatory limit.
Study Duration : October 2003 to November 2004
Contractor : Environ International Corporation
At the time this study was commissioned, the legislation required FSAS to close offshore king scallop fishing grounds (known as offshore boxes) when levels of the biotoxin domoic acid (DA) were at or exceeded the 20mg/kg regulatory level. In order to re-open these offshore boxes FSAS required two negative samples (i.e. below 20mg/kg) at least seven days apart. In order that the re-sampling of closed boxes could be targeted to periods when the DA concentrations were likely to have decreased below the regulatory level, a risk assessment was carried out.
This project looked at the DA patterns over time in each individual offshore box or groups of boxes to establish the time taken for potentially hazardous levels of DA in king scallops to fall below the regulatory limit. The work was conducted in parallel with FSAS-funded project S02020, which employed an alternative risk based approach to the Scottish offshore monitoring programme for DA in king scallops.
A database was created using the FSAS offshore monitoring data for DA levels in king scallops from July 1998 to March 2004. Data on episodes where DA concentrations exceeded the regulatory level of 20mg/kg were reviewed to attempt to correlate environmental variables. The aim of this study was to develop a time-course model to predict the levels of DA in scallops over time, based on other empirical variables, allowing the development of a decision tool to inform future monitoring and end product testing of DA in king scallops.
This research project developed a database of domoic acid (DA) concentrations in King Scallops in Scottish offshore waters, which was used to determine the time taken for levels in closed areas to fall below the regulatory limit.
At the time this study was commissioned, the legislation required FSAS to close offshore King Scallop fishing grounds (known as offshore boxes) when levels of the biotoxin Domoic Acid (DA) were at or exceeded the 20mg/kg regulatory level. In order to re-open these offshore boxes FSAS required two negative samples (ie below 20 mg/kg) at least seven days apart. In order that the re-sampling of closed boxes could be targeted to periods when the DA concentrations were likely to have decreased below the regulatory level, a risk assessment was carried out. This project looked at the DA patterns over time in each individual offshore box or groups of boxes to establish the time taken for potentially hazardous levels of DA in King Scallops to fall below the regulatory limit.. This work was conducted in parallel with FSAS funded project S02020, which employed an alternative risk based approach to the Scottish offshore monitoring programme for DA in King Scallops.
A database was created using the Scottish offshore monitoring data for DA levels in King Scallops from July 1998 -March 2004. This database was then used to investigate the time-course of DA concentrations in boxes that had been closed due to the detection of DA concentrations exceeding the regulatory level of 20 mg/kg. For each offshore box, the probability of obtaining a low concentration sample at different time periods following closure was determined, taking into account the following factors:
The magnitude of their effects, and the specific effect on the time-course probability predictions was determined by finding the best-fitting logistic regression models that included some function of time after closure. Models that provided a satisfactory fit to the data were found; the predictions (in both graphical and tabular form) of those best fitting models were displayed in an Excel spreadsheet. This spreadsheet provides a tool to indicate when high concentrations of DA in King Scallops in particular offshore boxes are likely to have decreased below the regulatory level.
The final report is available from the FSA Library and Information centre.
To obtain a copy, please contact the Enquiry Desk,
Dr Elsie Widdowson Library and Information Services, Food Standards Agency (tel: 020 7276 8181/8182 or email:
infocentre@foodstandards.gsi.gov.uk
).
Contact
: For any enquiries concerning this research project, please contact the relevant Programme contact or email
science@foodstandards.gsi.gov.uk
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