Oysters and Discharge points in the UK

The Food Standard Agency in the UK has recently published a "Review of approaches for establishing exclusion zones for shellfish harvesting around sewage discharge points".



As a result of this study came out a possible regulatory approach :

Exclusion zones to limit food
hygiene risks from shellfish harvested in close proximity to potentially
Norovirus-contaminated wastewater discharges.




Overseas examples have been studied, such as :



In Europe : proximity based zoning preclude shellfish production a set distance
from wastewater discharges, ports, marinas and rivers.



In the US : a combination of dilution and time-based
criteria to attain a bacteriological shellfish water quality standard.






Norovirus has a different risk
profile from bacterial Faecal Indicator Organisms (FIOs) used in food
hygiene and environmental management controls, as described in the litterature.

• Seasonal Norovirus loading in crude wastewater reflects the
  variation in ‘catchment health’ of the sewerage connected population.
• Waste Water Treatment Plants (WWTPs) are less effective at removing Norovirus than FIOs.
• UV disinfection efficacy and environmental degradation of Norovirus cannot be demonstrated using current analytical tools.
• Bioaccumulation of Norovirus from water into shellfish flesh has a
  very different mechanism from that of FIOs.  (Literature data suggests
  hyper-accumulation of viruses can occur during the winter.)

Read more about this study (© Food Standard Agency) at : 

Review of approaches for establishing exclusion zones for shellfish harvesting around sewage discharge points | food.gov.uk