All bathing water in the UK is tested and assessed by the Environment Agency from May to September.
Weekly assessments check the water quality and daily pollution risk forecasts are issued. Marine algae include seaweeds and microscopic plants called phytoplankton. A bloom is usually made up of one species and occurs when conditions for growth are ideal, often in the summer.
Some algae can harm marine creatures by producing toxins or clogging the gills of fish. Blooms of toxic algae are rare in English coastal waters. Some non-toxic blooms can be mistaken for sewage pollution. One of the most common bloom-forming algae in English coastal waters forms a brown, frothy scum. This is often blown onto the shore where it breaks down into an unpleasant brown slime that smells like sewage. This soon breaks down and disappears.
Here are some commonly asked questions regarding algae and other substances seen in the water:
Q. I can see a brown, frothy scum on the water surface and it smells like sewage. Is it safe to swim?
This is the most common type of algae in British coastal waters, Phaeocystis pouchetii. The blooms form a brown, frothy scum on the water’s surface and it is non-toxic, so it is safe to swim.
Q. I’ve noticed the water has turned orange, is this something to worry about?
This is nothing to worry about. The algae Noctiluca scintillans produces an orange discoloration of the water and is non-toxic.
Q. The tide has turned red. Should I make anyone aware?
If the entire water surface has turned red this can be toxic to marine creatures. Please contact the Environment Agency with any concerns on 0800 80 70 60.
Q. The water looks thick, sludgy and oily. Is this harmful to marine creatures?
If the water looks black and oily it could be an oil spill. This can be toxic to people, animals and marine creatures. If you think the water may be polluted please contact the Environment Agency immediately on 0800 80 70 60.
Q. I can see lots of litter in the sea and on the beach. Who do I report this to?
You can report this online at https://www.southend.gov.uk/MySouthend
Page last updated: 02/10/2019