International Photojournalist and Photographer

A slick of bubbling brown detritus flowing in a tributary of the river Conwy in North Wales is a possible cause of the deaths of  hundreds of small seawater crabs observed in the area around the pollution.

The slick, clearly visible and trapped  by the high tide, was washed into the mouth of the Conwy estuary as the tide ebbed.

At low tide today, the weeping storm outflow pipe and culverts for the small streams which flow into the area were clearly visible.

The estuary into which the tributary flows is an important mussel bed area.

Mussels have been harvested in the Conwy estuary for hundreds of years and they are quickly rendered unfit for human consumption in microbial polluted waters.

Trevor Jones from the Conwy mussel fishery informs me that: “For the last two years we have had no problem with pollution of the mussel beds. They have been classified safe to eat [after treatment] at level B.”

For mussels to be marketed for human consumption, the beds from which they are harvested must be classified according to criteria specified in the Food Safety (Fishery Products and Live Shellfish) (Hygiene) Regulations 1998. The classifications of designated mussel beds are determined by the level bacterial – ecoli – contamination present in the shellfish. Samples from the mussel beds are tested monthly. Class A beds produce shellfish which can be sold live for human consumption without any further treatment.  In the case of Class C beds, the shellfish have high contamination  levels and must either be heat-treated, or relaid in an approved area for at least 2 months before purification.

A level  B clasification means that mussels cannot be used for human consumption without tratment to kill any ecoli bacteria present in them. This treatment process takes place in closed sterile tanks on Conwy Quay during which the mussels are exposed to UV light for 48 hours.

“We did have problems over two years ago with ecoli in the mussels but since then they have been perfectly safe to eat,” Mr Jones stresses to me again.

Ecoli bacterial contamination in mussels arises from faecal – human, animal or bird – discharges into the water flow.

Chris Starr, a local mussel fisherman, told me that: “A yellow boat from Bangor University goes up and down the river testing the water.”

A joint Conwy council and  Bangor University team are currently investigating possible pollution sources in the river Conwy.

I was requested by the Environment Agency Wales to add this comment to my article:

Statement from Environment Agency Wales 08/06/11:

A spokesperson for Environment Agency Wales said: “We believe the photographs taken are probably of an algal scum not sewage or ‘a bubbling brown effluent’ as reported. We  visited and sampled water in the area on Tuesday and no algae or sewage was found but there have been a number of  recent reports of  naturally-occuring algae along the coast which has been mistaken for sewage. The weekend’s tides were significant and any dead organisms along the coast could easily have been picked up by the incoming tide and deposited. Should any member of the public wish to report pollution, they can contact us via our 24 hour emergency hotline on 0800 80 70 60.”